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codeql/python/ql/lib/semmle/python/frameworks/Stdlib.qll
Taus df0f2f8ce4 Python: Simple dataflow annotations 
None of these required any changes to the dataflow libraries, so it
seemed easiest to put them in their own commit.
2026-02-16 13:48:32 +00:00

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/**
* Provides classes modeling security-relevant aspects of the standard libraries.
* Note: some modeling is done internally in the dataflow/taint tracking implementation.
*/
overlay[local?]
module;
private import python
private import semmle.python.dataflow.new.DataFlow
private import semmle.python.dataflow.new.TaintTracking
private import semmle.python.dataflow.new.RemoteFlowSources
private import semmle.python.Concepts
private import semmle.python.ApiGraphs
private import semmle.python.dataflow.new.FlowSummary
private import semmle.python.frameworks.PEP249
private import semmle.python.frameworks.internal.PoorMansFunctionResolution
private import semmle.python.frameworks.internal.SelfRefMixin
private import semmle.python.frameworks.internal.InstanceTaintStepsHelper
// modeling split over multiple files to keep this file from becoming too big
private import semmle.python.frameworks.Stdlib.Urllib
private import semmle.python.frameworks.Stdlib.Urllib2
private import semmle.python.frameworks.data.ModelsAsData
/** Provides models for the Python standard library. */
module Stdlib {
/**
* Provides models for file-like objects,
* mostly to define standard set of extra taint-steps.
*
* See
* - https://docs.python.org/3.9/glossary.html#term-file-like-object
* - https://docs.python.org/3.9/library/io.html#io.IOBase
*/
module FileLikeObject {
/**
* A source of a file-like object, extend this class to model new instances.
*
* This can include instantiations of the class, return values from function
* calls, or a special parameter that will be set when functions are called by an external
* library.
*
* Use the predicate `like::instance()` to get references to instances of `file.like`.
*/
abstract class InstanceSource extends DataFlow::LocalSourceNode { }
/** Gets a reference to a file-like object. */
private DataFlow::TypeTrackingNode instance(DataFlow::TypeTracker t) {
t.start() and
result instanceof InstanceSource
or
exists(DataFlow::TypeTracker t2 | result = instance(t2).track(t2, t))
}
/** Gets a reference to a file-like object. */
DataFlow::Node instance() { instance(DataFlow::TypeTracker::end()).flowsTo(result) }
/**
* Taint propagation for file-like objects.
*/
private class InstanceTaintSteps extends InstanceTaintStepsHelper {
InstanceTaintSteps() { this = "<file-like object>" }
override DataFlow::Node getInstance() { result = instance() }
override string getAttributeName() { none() }
override string getMethodName() { result in ["read", "readline", "readlines"] }
override string getAsyncMethodName() { none() }
}
/**
* Extra taint propagation for file-like objects, not covered by `InstanceTaintSteps`.",
*/
private class AdditionalTaintStep extends TaintTracking::AdditionalTaintStep {
override predicate step(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {
// taint-propagation back to instance from `foo.write(tainted_data)`
exists(DataFlow::AttrRead write, DataFlow::CallCfgNode call, DataFlow::Node instance_ |
instance_ = instance() and
write.accesses(instance_, "write")
|
nodeTo.(DataFlow::PostUpdateNode).getPreUpdateNode() = instance_ and
call.getFunction() = write and
nodeFrom = call.getArg(0)
)
}
}
}
/**
* Provides models for the `http.client.HTTPMessage` class
*
* Has no official docs, but see
* https://github.com/python/cpython/blob/64f54b7ccd49764b0304e076bfd79b5482988f53/Lib/http/client.py#L175
* and https://docs.python.org/3.9/library/email.compat32-message.html#email.message.Message
*/
module HttpMessage {
/**
* A source of instances of `http.client.HTTPMessage`, extend this class to model new instances.
*
* This can include instantiations of the class, return values from function
* calls, or a special parameter that will be set when functions are called by an external
* library.
*
* Use the predicate `HTTPMessage::instance()` to get references to instances of `http.client.HTTPMessage`.
*/
abstract class InstanceSource extends DataFlow::LocalSourceNode { }
/** Gets a reference to an instance of `http.client.HttpMessage`. */
private DataFlow::TypeTrackingNode instance(DataFlow::TypeTracker t) {
t.start() and
result instanceof InstanceSource
or
exists(DataFlow::TypeTracker t2 | result = instance(t2).track(t2, t))
}
/** Gets a reference to an instance of `http.client.HttpMessage`. */
DataFlow::Node instance() { instance(DataFlow::TypeTracker::end()).flowsTo(result) }
/**
* Taint propagation for `http.client.HTTPMessage`.
*/
private class InstanceTaintSteps extends InstanceTaintStepsHelper {
InstanceTaintSteps() { this = "http.client.HTTPMessage" }
override DataFlow::Node getInstance() { result = instance() }
override string getAttributeName() { none() }
override string getMethodName() { result in ["get_all", "as_bytes", "as_string", "keys"] }
override string getAsyncMethodName() { none() }
}
}
/**
* Provides models for the `http.cookies.Morsel` class
*
* See https://docs.python.org/3.9/library/http.cookies.html#http.cookies.Morsel.
*/
module Morsel {
/**
* A source of instances of `http.cookies.Morsel`, extend this class to model new instances.
*
* This can include instantiations of the class, return values from function
* calls, or a special parameter that will be set when functions are called by an external
* library.
*
* Use the predicate `Morsel::instance()` to get references to instances of `http.cookies.Morsel`.
*/
abstract class InstanceSource extends DataFlow::LocalSourceNode { }
/** Gets a reference to an instance of `http.cookies.Morsel`. */
private DataFlow::TypeTrackingNode instance(DataFlow::TypeTracker t) {
t.start() and
result instanceof InstanceSource
or
exists(DataFlow::TypeTracker t2 | result = instance(t2).track(t2, t))
}
/** Gets a reference to an instance of `http.cookies.Morsel`. */
DataFlow::Node instance() { instance(DataFlow::TypeTracker::end()).flowsTo(result) }
/**
* Taint propagation for `http.cookies.Morsel`.
*/
private class InstanceTaintSteps extends InstanceTaintStepsHelper {
InstanceTaintSteps() { this = "http.cookies.Morsel" }
override DataFlow::Node getInstance() { result = instance() }
override string getAttributeName() { result in ["key", "value", "coded_value"] }
override string getMethodName() { result in ["output", "js_output"] }
override string getAsyncMethodName() { none() }
}
}
/**
* Provides models for the `urllib.parse.SplitResult` class
*
* See https://docs.python.org/3.9/library/urllib.parse.html#urllib.parse.SplitResult.
*/
module SplitResult {
/** Gets a reference to the `urllib.parse.SplitResult` class. */
API::Node classRef() {
result = API::moduleImport("urllib").getMember("parse").getMember("SplitResult")
or
result = ModelOutput::getATypeNode("urllib.parse.SplitResult~Subclass").getASubclass*()
}
/**
* A source of instances of `urllib.parse.SplitResult`, extend this class to model new instances.
*
* This can include instantiations of the class, return values from function
* calls, or a special parameter that will be set when functions are called by an external
* library.
*
* Use the predicate `SplitResult::instance()` to get references to instances of `urllib.parse.SplitResult`.
*/
abstract class InstanceSource extends DataFlow::LocalSourceNode { }
/** A direct instantiation of `urllib.parse.SplitResult`. */
private class ClassInstantiation extends InstanceSource, DataFlow::CallCfgNode {
ClassInstantiation() { this = classRef().getACall() }
}
/** Gets a reference to an instance of `urllib.parse.SplitResult`. */
private DataFlow::TypeTrackingNode instance(DataFlow::TypeTracker t) {
t.start() and
result instanceof InstanceSource
or
exists(DataFlow::TypeTracker t2 | result = instance(t2).track(t2, t))
}
/** Gets a reference to an instance of `urllib.parse.SplitResult`. */
DataFlow::Node instance() { instance(DataFlow::TypeTracker::end()).flowsTo(result) }
/**
* Taint propagation for `urllib.parse.SplitResult`.
*/
private class InstanceTaintSteps extends InstanceTaintStepsHelper {
InstanceTaintSteps() { this = "urllib.parse.SplitResult" }
override DataFlow::Node getInstance() { result = instance() }
override string getAttributeName() {
result in [
"netloc", "path", "query", "fragment", "username", "password", "hostname", "port"
]
}
override string getMethodName() { none() }
override string getAsyncMethodName() { none() }
}
/**
* Extra taint propagation for `urllib.parse.SplitResult`, not covered by `InstanceTaintSteps`.
*/
private class AdditionalTaintStep extends TaintTracking::AdditionalTaintStep {
override predicate step(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {
// TODO
none()
}
}
}
/**
* Provides models for the `urllib.parse.ParseResult` class
*
* See https://docs.python.org/3.9/library/urllib.parse.html#urllib.parse.ParseResult.
*/
module ParseResult {
/** Gets a reference to the `urllib.parse.ParseResult` class. */
API::Node classRef() {
result = API::moduleImport("urllib").getMember("parse").getMember("ParseResult")
or
result = ModelOutput::getATypeNode("urllib.parse.ParseResult~Subclass").getASubclass*()
}
/**
* A source of instances of `urllib.parse.ParseResult`, extend this class to model new instances.
*
* This can include instantiations of the class, return values from function
* calls, or a special parameter that will be set when functions are called by an external
* library.
*
* Use the predicate `ParseResult::instance()` to get references to instances of `urllib.parse.ParseResult`.
*/
abstract class InstanceSource extends DataFlow::LocalSourceNode { }
/** A direct instantiation of `urllib.parse.ParseResult`. */
private class ClassInstantiation extends InstanceSource, DataFlow::CallCfgNode {
ClassInstantiation() { this = classRef().getACall() }
}
/** Gets a reference to an instance of `urllib.parse.ParseResult`. */
private DataFlow::TypeTrackingNode instance(DataFlow::TypeTracker t) {
t.start() and
result instanceof InstanceSource
or
exists(DataFlow::TypeTracker t2 | result = instance(t2).track(t2, t))
}
/** Gets a reference to an instance of `urllib.parse.ParseResult`. */
DataFlow::Node instance() { instance(DataFlow::TypeTracker::end()).flowsTo(result) }
/**
* Taint propagation for `urllib.parse.ParseResult`.
*/
private class InstanceTaintSteps extends InstanceTaintStepsHelper {
InstanceTaintSteps() { this = "urllib.parse.ParseResult" }
override DataFlow::Node getInstance() { result = instance() }
override string getAttributeName() {
result in [
"netloc", "path", "params", "query", "fragment", "username", "password", "hostname",
"port"
]
}
override string getMethodName() { none() }
override string getAsyncMethodName() { none() }
}
}
// ---------------------------------------------------------------------------
// logging
// ---------------------------------------------------------------------------
/**
* Provides models for the `logging.Logger` class and subclasses.
*
* See https://docs.python.org/3.9/library/logging.html#logging.Logger.
*/
module Logger {
private import semmle.python.dataflow.new.internal.DataFlowDispatch as DD
/** Gets a reference to the `logging.Logger` class or any subclass. */
API::Node subclassRef() {
result = API::moduleImport("logging").getMember("Logger").getASubclass*()
or
result = API::moduleImport("logging").getMember("getLoggerClass").getReturn().getASubclass*()
or
result = ModelOutput::getATypeNode("logging.Logger~Subclass").getASubclass*()
}
/**
* A source of instances of `logging.Logger`, extend this class to model new instances.
*
* This can include instantiations of the class, return values from function
* calls, or a special parameter that will be set when functions are called by an external
* library.
*
* Use the predicate `Logger::instance()` to get references to instances of `logging.Logger`.
*/
abstract class InstanceSource extends DataFlow::LocalSourceNode { }
/** A direct instantiation of `logging.Logger`. */
private class ClassInstantiation extends InstanceSource, DataFlow::CfgNode {
ClassInstantiation() {
this = subclassRef().getACall()
or
this =
DD::selfTracker(subclassRef()
.getAValueReachableFromSource()
.asExpr()
.(ClassExpr)
.getInnerScope())
or
this = API::moduleImport("logging").getMember("root").asSource()
or
this = API::moduleImport("logging").getMember("getLogger").getACall()
}
}
/** Gets a reference to an instance of `logging.Logger`. */
private DataFlow::TypeTrackingNode instance(DataFlow::TypeTracker t) {
t.start() and
result instanceof InstanceSource
or
exists(DataFlow::TypeTracker t2 | result = instance(t2).track(t2, t))
}
/** Gets a reference to an instance of `logging.Logger`. */
DataFlow::Node instance() { instance(DataFlow::TypeTracker::end()).flowsTo(result) }
}
}
/**
* INTERNAL: Do not use.
*
* Provides models for the Python standard library.
*
* This module is marked private as exposing it means committing to 1-year deprecation
* policy, and the code is not in a polished enough state that we want to do so -- at
* least not without having convincing use-cases for it :)
*/
module StdlibPrivate {
// ---------------------------------------------------------------------------
// os
// ---------------------------------------------------------------------------
/** Gets a reference to the `os` module. */
API::Node os() { result = API::moduleImport("os") }
/** Provides models for the `os` module. */
module OS {
/** Gets a reference to the `os.path` module. */
API::Node path() {
result = os().getMember("path")
or
// although the following modules should not be used directly, they certainly can.
// Each one doesn't expose the full `os.path` API, so this is an overapproximation
// that made implementation easy. See
// - https://github.com/python/cpython/blob/b567b9d74bd9e476a3027335873bb0508d6e450f/Lib/posixpath.py#L31-L38
// - https://github.com/python/cpython/blob/b567b9d74bd9e476a3027335873bb0508d6e450f/Lib/ntpath.py#L26-L32
// - https://github.com/python/cpython/blob/b567b9d74bd9e476a3027335873bb0508d6e450f/Lib/genericpath.py#L9-L11
result = API::moduleImport(["posixpath", "ntpath", "genericpath"])
}
/** Provides models for the `os.path` module */
module OsPath {
/** Gets a reference to the `os.path.join` function. */
API::Node join() { result = path().getMember("join") }
}
}
/**
* Modeling of path related functions in the `os` module.
* Wrapped in QL module to make it easy to fold/unfold.
*/
module OsFileSystemAccessModeling {
/**
* A call to the `os.fsencode` function.
*
* See https://docs.python.org/3/library/os.html#os.fsencode
*/
private class OsFsencodeCall extends Encoding::Range, DataFlow::CallCfgNode {
OsFsencodeCall() { this = os().getMember("fsencode").getACall() }
override DataFlow::Node getAnInput() {
result in [this.getArg(0), this.getArgByName("filename")]
}
override DataFlow::Node getOutput() { result = this }
override string getFormat() { result = "filesystem" }
}
/**
* A call to the `os.fsdecode` function.
*
* See https://docs.python.org/3/library/os.html#os.fsdecode
*/
private class OsFsdecodeCall extends Decoding::Range, DataFlow::CallCfgNode {
OsFsdecodeCall() { this = os().getMember("fsdecode").getACall() }
override DataFlow::Node getAnInput() {
result in [this.getArg(0), this.getArgByName("filename")]
}
override DataFlow::Node getOutput() { result = this }
override string getFormat() { result = "filesystem" }
override predicate mayExecuteInput() { none() }
}
/**
* Additional taint step from a call to the `os.fspath` function.
*
* See https://docs.python.org/3/library/os.html#os.fspath
*/
private class OsFspathCallAdditionalTaintStep extends TaintTracking::AdditionalTaintStep {
override predicate step(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {
exists(DataFlow::CallCfgNode call |
call = os().getMember("fspath").getACall() and
nodeFrom in [call.getArg(0), call.getArgByName("path")] and
nodeTo = call
)
}
}
/**
* A call to the `os.open` function.
*
* See https://docs.python.org/3/library/os.html#os.open
*/
class OsOpenCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsOpenCall() { this = os().getMember("open").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.access` function.
*
* See https://docs.python.org/3/library/os.html#os.access
*/
private class OsAccessCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsAccessCall() { this = os().getMember("access").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.chdir` function.
*
* See https://docs.python.org/3/library/os.html#os.chdir
*/
private class OsChdirCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsChdirCall() { this = os().getMember("chdir").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.chflags` function.
*
* See https://docs.python.org/3/library/os.html#os.chflags
*/
private class OsChflagsCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsChflagsCall() { this = os().getMember("chflags").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.chmod` function.
*
* See https://docs.python.org/3/library/os.html#os.chmod
*/
private class OsChmodCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsChmodCall() { this = os().getMember("chmod").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.chown` function.
*
* See https://docs.python.org/3/library/os.html#os.chown
*/
private class OsChownCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsChownCall() { this = os().getMember("chown").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.chroot` function.
*
* See https://docs.python.org/3/library/os.html#os.chroot
*/
private class OsChrootCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsChrootCall() { this = os().getMember("chroot").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.lchflags` function.
*
* See https://docs.python.org/3/library/os.html#os.lchflags
*/
private class OsLchflagsCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsLchflagsCall() { this = os().getMember("lchflags").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.lchmod` function.
*
* See https://docs.python.org/3/library/os.html#os.lchmod
*/
private class OsLchmodCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsLchmodCall() { this = os().getMember("lchmod").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.lchown` function.
*
* See https://docs.python.org/3/library/os.html#os.lchown
*/
private class OsLchownCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsLchownCall() { this = os().getMember("lchown").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.link` function.
*
* See https://docs.python.org/3/library/os.html#os.link
*/
private class OsLinkCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsLinkCall() { this = os().getMember("link").getACall() }
override DataFlow::Node getAPathArgument() {
result in [
this.getArg(0), this.getArgByName("src"), this.getArg(1), this.getArgByName("dst")
]
}
}
/**
* A call to the `os.listdir` function.
*
* See https://docs.python.org/3/library/os.html#os.listdir
*/
private class OsListdirCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsListdirCall() { this = os().getMember("listdir").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.lstat` function.
*
* See https://docs.python.org/3/library/os.html#os.lstat
*/
private class OsLstatCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsLstatCall() { this = os().getMember("lstat").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.mkdir` function.
*
* See https://docs.python.org/3/library/os.html#os.mkdir
*/
private class OsMkdirCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsMkdirCall() { this = os().getMember("mkdir").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.makedirs` function.
*
* See https://docs.python.org/3/library/os.html#os.makedirs
*/
private class OsMakedirsCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsMakedirsCall() { this = os().getMember("makedirs").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("name")]
}
}
/**
* A call to the `os.mkfifo` function.
*
* See https://docs.python.org/3/library/os.html#os.mkfifo
*/
private class OsMkfifoCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsMkfifoCall() { this = os().getMember("mkfifo").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.mknod` function.
*
* See https://docs.python.org/3/library/os.html#os.mknod
*/
private class OsMknodCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsMknodCall() { this = os().getMember("mknod").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.pathconf` function.
*
* See https://docs.python.org/3/library/os.html#os.pathconf
*/
private class OsPathconfCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsPathconfCall() { this = os().getMember("pathconf").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.readlink` function.
*
* See https://docs.python.org/3/library/os.html#os.readlink
*/
private class OsReadlinkCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsReadlinkCall() { this = os().getMember("readlink").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.remove` function.
*
* See https://docs.python.org/3/library/os.html#os.remove
*/
private class OsRemoveCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsRemoveCall() { this = os().getMember("remove").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.removedirs` function.
*
* See https://docs.python.org/3/library/os.html#os.removedirs
*/
private class OsRemovedirsCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsRemovedirsCall() { this = os().getMember("removedirs").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("name")]
}
}
/**
* A call to the `os.rename` function.
*
* See https://docs.python.org/3/library/os.html#os.rename
*/
private class OsRenameCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsRenameCall() { this = os().getMember("rename").getACall() }
override DataFlow::Node getAPathArgument() {
result in [
this.getArg(0), this.getArgByName("src"), this.getArg(1), this.getArgByName("dst")
]
}
}
/**
* A call to the `os.renames` function.
*
* See https://docs.python.org/3/library/os.html#os.renames
*/
private class OsRenamesCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsRenamesCall() { this = os().getMember("renames").getACall() }
override DataFlow::Node getAPathArgument() {
result in [
this.getArg(0), this.getArgByName("old"), this.getArg(1), this.getArgByName("new")
]
}
}
/**
* A call to the `os.replace` function.
*
* See https://docs.python.org/3/library/os.html#os.replace
*/
private class OsReplaceCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsReplaceCall() { this = os().getMember("replace").getACall() }
override DataFlow::Node getAPathArgument() {
result in [
this.getArg(0), this.getArgByName("src"), this.getArg(1), this.getArgByName("dst")
]
}
}
/**
* A call to the `os.rmdir` function.
*
* See https://docs.python.org/3/library/os.html#os.rmdir
*/
private class OsRmdirCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsRmdirCall() { this = os().getMember("rmdir").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.scandir` function.
*
* See https://docs.python.org/3/library/os.html#os.scandir
*/
private class OsScandirCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsScandirCall() { this = os().getMember("scandir").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.stat` function.
*
* See https://docs.python.org/3/library/os.html#os.stat
*/
private class OsStatCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsStatCall() { this = os().getMember("stat").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.statvfs` function.
*
* See https://docs.python.org/3/library/os.html#os.statvfs
*/
private class OsStatvfsCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsStatvfsCall() { this = os().getMember("statvfs").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.symlink` function.
*
* See https://docs.python.org/3/library/os.html#os.symlink
*/
private class OsSymlinkCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsSymlinkCall() { this = os().getMember("symlink").getACall() }
override DataFlow::Node getAPathArgument() {
result in [
this.getArg(0), this.getArgByName("src"), this.getArg(1), this.getArgByName("dst")
]
}
}
/**
* A call to the `os.truncate` function.
*
* See https://docs.python.org/3/library/os.html#os.truncate
*/
private class OsTruncateCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsTruncateCall() { this = os().getMember("truncate").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.unlink` function.
*
* See https://docs.python.org/3/library/os.html#os.unlink
*/
private class OsUnlinkCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsUnlinkCall() { this = os().getMember("unlink").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.utime` function.
*
* See https://docs.python.org/3/library/os.html#os.utime
*/
private class OsUtimeCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsUtimeCall() { this = os().getMember("utime").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.walk` function.
*
* See https://docs.python.org/3/library/os.html#os.walk
*/
private class OsWalkCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsWalkCall() { this = os().getMember("walk").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("top")]
}
}
/**
* A call to the `os.fwalk` function.
*
* See https://docs.python.org/3/library/os.html#os.fwalk
*/
private class OsFwalkCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsFwalkCall() { this = os().getMember("fwalk").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("top")]
}
}
/**
* A call to the `os.getxattr` function.
*
* See https://docs.python.org/3/library/os.html#os.getxattr
*/
private class OsGetxattrCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsGetxattrCall() { this = os().getMember("getxattr").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.listxattr` function.
*
* See https://docs.python.org/3/library/os.html#os.listxattr
*/
private class OsListxattrCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsListxattrCall() { this = os().getMember("listxattr").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.removexattr` function.
*
* See https://docs.python.org/3/library/os.html#os.removexattr
*/
private class OsRemovexattrCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsRemovexattrCall() { this = os().getMember("removexattr").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.setxattr` function.
*
* See https://docs.python.org/3/library/os.html#os.setxattr
*/
private class OsSetxattrCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsSetxattrCall() { this = os().getMember("setxattr").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.add_dll_directory` function.
*
* See https://docs.python.org/3/library/os.html#os.add_dll_directory
*/
private class OsAdd_dll_directoryCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsAdd_dll_directoryCall() { this = os().getMember("add_dll_directory").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `os.startfile` function.
*
* See https://docs.python.org/3/library/os.html#os.startfile
*/
private class OsStartfileCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsStartfileCall() { this = os().getMember("startfile").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
}
/**
* The `os.path` module offers a number of methods for checking if a file exists and/or has certain
* properties, leading to a file system access.
* A call to `os.path.exists` or `os.path.lexists` will check if a file exists on the file system.
* (Although, on some platforms, the check may return `false` due to missing permissions.)
* A call to `os.path.getatime` will raise `OSError` if the file does not exist or is inaccessible.
* See:
* - https://docs.python.org/3/library/os.path.html#os.path.exists
* - https://docs.python.org/3/library/os.path.html#os.path.lexists
* - https://docs.python.org/3/library/os.path.html#os.path.isfile
* - https://docs.python.org/3/library/os.path.html#os.path.isdir
* - https://docs.python.org/3/library/os.path.html#os.path.islink
* - https://docs.python.org/3/library/os.path.html#os.path.ismount
* - https://docs.python.org/3/library/os.path.html#os.path.getatime
* - https://docs.python.org/3/library/os.path.html#os.path.getmtime
* - https://docs.python.org/3/library/os.path.html#os.path.getctime
* - https://docs.python.org/3/library/os.path.html#os.path.getsize
* - https://docs.python.org/3/library/os.path.html#os.path.realpath
*/
private class OsPathProbingCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
string name;
OsPathProbingCall() {
name in [
// these check if the file exists
"exists", "lexists", "isfile", "isdir", "islink", "ismount",
// these raise errors if the file does not exist
"getatime", "getmtime", "getctime", "getsize"
] and
this = OS::path().getMember(name).getACall()
}
override DataFlow::Node getAPathArgument() {
not name = "isdir" and
result in [this.getArg(0), this.getArgByName("path")]
or
// although the Python docs say the parameter is called `path`, the implementation
// actually uses `s`.
name = "isdir" and
result in [this.getArg(0), this.getArgByName("s")]
}
}
/**
* A call to `os.path.samefile` will raise an exception if an `os.stat()` call on either pathname fails.
*
* See https://docs.python.org/3.10/library/os.path.html#os.path.samefile
*/
private class OsPathSamefileCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
OsPathSamefileCall() { this = OS::path().getMember("samefile").getACall() }
override DataFlow::Node getAPathArgument() {
result in [
// note that the f1/f2 names doesn't match the documentation, but is what actually works (tested on 3.8.10)
this.getArg(0), this.getArgByName("f1"), this.getArg(1), this.getArgByName("f2")
]
}
}
// Functions with non-standard arguments:
// - os.path.join(path, *paths)
// - os.path.relpath(path, start=os.curdir)
// these functions need special treatment when computing `getPathArg`.
//
// Functions that excluded because they can act as sanitizers:
// - os.path.commonpath(paths): takes a sequence
// - os.path.commonprefix(list): takes a list argument
// unless the user control all arguments, we are comparing with a known value.
private string pathComputation() {
result in [
"abspath", "basename", "commonpath", "dirname", "expanduser", "expandvars", "join",
"normcase", "normpath", "realpath", "relpath", "split", "splitdrive", "splitext"
]
}
/**
* The `os.path` module offers a number of methods for computing new paths from existing paths.
* These should all propagate taint.
*/
private class OsPathComputation extends DataFlow::CallCfgNode {
string methodName;
OsPathComputation() {
methodName = pathComputation() and
this = OS::path().getMember(methodName).getACall()
}
DataFlow::Node getPathArg() {
result in [this.getArg(0), this.getArgByName("path")]
or
methodName = "join" and result = this.getArg(_)
or
methodName = "relpath" and result in [this.getArg(1), this.getArgByName("start")]
}
}
/** An additional taint step for path computations. */
private class OsPathComputationAdditionalTaintStep extends TaintTracking::AdditionalTaintStep {
override predicate step(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {
exists(OsPathComputation call |
nodeTo = call and
nodeFrom = call.getPathArg()
)
}
}
/**
* A call to `os.path.normpath`.
* See https://docs.python.org/3/library/os.path.html#os.path.normpath
*/
private class OsPathNormpathCall extends Path::PathNormalization::Range, DataFlow::CallCfgNode {
OsPathNormpathCall() { this = OS::path().getMember("normpath").getACall() }
override DataFlow::Node getPathArg() { result in [this.getArg(0), this.getArgByName("path")] }
}
/**
* A call to `os.path.abspath`.
* See https://docs.python.org/3/library/os.path.html#os.path.abspath
*/
private class OsPathAbspathCall extends Path::PathNormalization::Range, DataFlow::CallCfgNode {
OsPathAbspathCall() { this = OS::path().getMember("abspath").getACall() }
override DataFlow::Node getPathArg() { result in [this.getArg(0), this.getArgByName("path")] }
}
/**
* A call to `os.path.realpath`.
* See https://docs.python.org/3/library/os.path.html#os.path.realpath
*/
private class OsPathRealpathCall extends Path::PathNormalization::Range, DataFlow::CallCfgNode {
OsPathRealpathCall() { this = OS::path().getMember("realpath").getACall() }
override DataFlow::Node getPathArg() { result in [this.getArg(0), this.getArgByName("path")] }
}
/**
* A call to `os.system`.
* See https://docs.python.org/3/library/os.html#os.system
*/
private class OsSystemCall extends SystemCommandExecution::Range, DataFlow::CallCfgNode {
OsSystemCall() { this = os().getMember("system").getACall() }
override DataFlow::Node getCommand() {
result in [this.getArg(0), this.getArgByName("command")]
}
override predicate isShellInterpreted(DataFlow::Node arg) { arg = this.getCommand() }
}
/**
* A call to any of the `os.popen*` functions
* See https://docs.python.org/3/library/os.html#os.popen
*
* Note that in Python 2, there are also `popen2`, `popen3`, and `popen4` functions.
* Although deprecated since version 2.6, they still work in 2.7.
* See https://docs.python.org/2.7/library/os.html#os.popen2
*/
private class OsPopenCall extends SystemCommandExecution::Range, API::CallNode {
string name;
OsPopenCall() {
name in ["popen", "popen2", "popen3", "popen4"] and
this = os().getMember(name).getACall()
}
override DataFlow::Node getCommand() {
result = this.getArg(0)
or
not name = "popen" and
result = this.getArgByName("cmd")
}
override predicate isShellInterpreted(DataFlow::Node arg) { arg = this.getCommand() }
}
/**
* A call to any of the `os.exec*` functions
* See https://docs.python.org/3.8/library/os.html#os.execl
*/
private class OsExecCall extends SystemCommandExecution::Range, FileSystemAccess::Range,
DataFlow::CallCfgNode
{
OsExecCall() {
exists(string name |
name in ["execl", "execle", "execlp", "execlpe", "execv", "execve", "execvp", "execvpe"] and
this = os().getMember(name).getACall()
)
}
override DataFlow::Node getCommand() { result = this.getArg(0) }
override DataFlow::Node getAPathArgument() { result = this.getCommand() }
override predicate isShellInterpreted(DataFlow::Node arg) {
none() // this is a safe API.
}
}
/**
* A call to any of the `os.spawn*` functions
* See https://docs.python.org/3.8/library/os.html#os.spawnl
*/
private class OsSpawnCall extends SystemCommandExecution::Range, FileSystemAccess::Range,
DataFlow::CallCfgNode
{
OsSpawnCall() {
exists(string name |
name in [
"spawnl", "spawnle", "spawnlp", "spawnlpe", "spawnv", "spawnve", "spawnvp", "spawnvpe"
] and
this = os().getMember(name).getACall()
)
}
override DataFlow::Node getCommand() {
result = this.getArg(1)
or
// `file` keyword argument only valid for the `v` variants, but this
// over-approximation is not hurting anyone, and is easy to implement.
result = this.getArgByName("file")
}
override DataFlow::Node getAPathArgument() { result = this.getCommand() }
override predicate isShellInterpreted(DataFlow::Node arg) {
none() // this is a safe API.
}
}
/**
* A call to any of the `os.posix_spawn*` functions
* See https://docs.python.org/3.8/library/os.html#os.posix_spawn
*/
private class OsPosixSpawnCall extends SystemCommandExecution::Range, FileSystemAccess::Range,
DataFlow::CallCfgNode
{
OsPosixSpawnCall() { this = os().getMember(["posix_spawn", "posix_spawnp"]).getACall() }
override DataFlow::Node getCommand() { result in [this.getArg(0), this.getArgByName("path")] }
override DataFlow::Node getAPathArgument() { result = this.getCommand() }
override predicate isShellInterpreted(DataFlow::Node arg) {
none() // this is a safe API.
}
}
/** An additional taint step for calls to `os.path.join` */
private class OsPathJoinCallAdditionalTaintStep extends TaintTracking::AdditionalTaintStep {
override predicate step(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {
exists(CallNode call |
nodeTo.asCfgNode() = call and
call = OS::OsPath::join().getACall().asCfgNode() and
call.getAnArg() = nodeFrom.asCfgNode()
)
// TODO: Handle pathlib (like we do for os.path.join)
}
}
// ---------------------------------------------------------------------------
// subprocess
// ---------------------------------------------------------------------------
/** Gets a reference to the `subprocess` module. */
API::Node subprocess() { result = API::moduleImport("subprocess") }
/**
* A call to `subprocess.Popen` or helper functions (call, check_call, check_output, run, getoutput, getstatusoutput)
* See https://docs.python.org/3.8/library/subprocess.html#subprocess.Popen
* ref: https://docs.python.org/3/library/subprocess.html#legacy-shell-invocation-functions
*/
private class SubprocessPopenCall extends SystemCommandExecution::Range, API::CallNode {
SubprocessPopenCall() {
exists(string name |
name in [
"Popen", "call", "check_call", "check_output", "run", "getoutput", "getstatusoutput"
] and
this = subprocess().getMember(name).getACall()
)
}
/** Gets the API-node for the `args` argument, if any. */
private API::Node get_args_arg() { result = this.getParameter(0, "args") }
/** Gets the API-node for the `shell` argument, if any. */
private API::Node get_shell_arg() { result = this.getParameter(8, "shell") }
private boolean get_shell_arg_value() {
not exists(this.get_shell_arg()) and
result = false
or
result =
this.get_shell_arg().getAValueReachingSink().asExpr().(ImmutableLiteral).booleanValue()
or
not this.get_shell_arg().getAValueReachingSink().asExpr() instanceof ImmutableLiteral and
result = false // defaults to `False`
}
/** Gets the API-node for the `executable` argument, if any. */
private API::Node get_executable_arg() { result = this.getParameter(2, "executable") }
override DataFlow::Node getCommand() {
// TODO: Track arguments ("args" and "shell")
// TODO: Handle using `args=["sh", "-c", <user-input>]`
result = this.get_executable_arg().asSink()
or
exists(DataFlow::Node arg_args, boolean shell |
arg_args = this.get_args_arg().asSink() and
shell = this.get_shell_arg_value()
|
// When "executable" argument is set, and "shell" argument is `False`, the
// "args" argument will only be used to set the program name and arguments to
// the program, so we should not consider any of them as command execution.
not (
exists(this.get_executable_arg()) and
shell = false
) and
(
// When the "args" argument is an iterable, first element is the command to
// run, so if we're able to, we only mark the first element as the command
// (and not the arguments to the command).
//
result.asCfgNode() = arg_args.asCfgNode().(SequenceNode).getElement(0)
or
// Either the "args" argument is not a sequence (which is valid) or we where
// just not able to figure it out. Simply mark the "args" argument as the
// command.
//
not arg_args.asCfgNode() instanceof SequenceNode and
result = arg_args
)
)
}
override predicate isShellInterpreted(DataFlow::Node arg) {
arg = [this.get_executable_arg(), this.get_args_arg()].asSink() and
this.get_shell_arg_value() = true
}
}
// ---------------------------------------------------------------------------
// marshal
// ---------------------------------------------------------------------------
/**
* A call to `marshal.load`
* See https://docs.python.org/3/library/marshal.html#marshal.load
*/
private class MarshalLoadCall extends Decoding::Range, DataFlow::CallCfgNode {
MarshalLoadCall() { this = API::moduleImport("marshal").getMember("load").getACall() }
override predicate mayExecuteInput() { any() }
override DataFlow::Node getAnInput() { result = this.getArg(0) }
override DataFlow::Node getOutput() { result = this }
override string getFormat() { result = "marshal" }
}
/**
* A call to `marshal.loads`
* See https://docs.python.org/3/library/marshal.html#marshal.loads
*/
private class MarshalLoadsCall extends Decoding::Range, DataFlow::CallCfgNode {
MarshalLoadsCall() { this = API::moduleImport("marshal").getMember("loads").getACall() }
override predicate mayExecuteInput() { any() }
override DataFlow::Node getAnInput() { result = this.getArg(0) }
override DataFlow::Node getOutput() { result = this }
override string getFormat() { result = "marshal" }
}
// ---------------------------------------------------------------------------
// pickle
// ---------------------------------------------------------------------------
/** Gets a reference to any of the `pickle` modules. */
API::Node pickle() {
result = API::moduleImport(["pickle", "cPickle", "_pickle"])
or
result = ModelOutput::getATypeNode("pickle~Alias")
}
/**
* Gets a reference to `pickle.load`
*/
API::Node pickle_load() {
result = pickle().getMember("load")
or
result = ModelOutput::getATypeNode("pickle.load~Alias")
}
/**
* Gets a reference to `pickle.loads`
*/
API::Node pickle_loads() {
result = pickle().getMember("loads")
or
result = ModelOutput::getATypeNode("pickle.loads~Alias")
}
/**
* A call to `pickle.load`
* See https://docs.python.org/3/library/pickle.html#pickle.load
*/
private class PickleLoadCall extends Decoding::Range, API::CallNode {
PickleLoadCall() { this = pickle_load().getACall() }
override predicate mayExecuteInput() { any() }
override DataFlow::Node getAnInput() { result in [this.getArg(0), this.getArgByName("file")] }
override DataFlow::Node getOutput() { result = this }
override string getFormat() { result = "pickle" }
}
/**
* A call to `pickle.loads`
* See https://docs.python.org/3/library/pickle.html#pickle.loads
*/
private class PickleLoadsCall extends Decoding::Range, API::CallNode {
PickleLoadsCall() { this = pickle_loads().getACall() }
override predicate mayExecuteInput() { any() }
override DataFlow::Node getAnInput() { result in [this.getArg(0), this.getArgByName("data")] }
override DataFlow::Node getOutput() { result = this }
override string getFormat() { result = "pickle" }
}
/**
* A construction of a `pickle.Unpickler`
* See https://docs.python.org/3/library/pickle.html#pickle.Unpickler
*/
private class PickleUnpicklerCall extends Decoding::Range, DataFlow::CallCfgNode {
PickleUnpicklerCall() { this = pickle().getMember("Unpickler").getACall() }
override predicate mayExecuteInput() { any() }
override DataFlow::Node getAnInput() { result in [this.getArg(0), this.getArgByName("file")] }
override DataFlow::Node getOutput() { result = this.getAMethodCall("load") }
override string getFormat() { result = "pickle" }
}
// ---------------------------------------------------------------------------
// shelve
// ---------------------------------------------------------------------------
/**
* A call to `shelve.open`
* See https://docs.python.org/3/library/shelve.html#shelve.open
*
* Claiming there is decoding of the input to `shelve.open` is a bit questionable, since
* it's not the filename, but the contents of the file that is decoded.
*
* However, we definitely want to be able to alert if a user is able to control what
* file is used, since that can lead to code execution (even if that file is free of
* path injection).
*
* So right now the best way we have of modeling this seems to be to treat the filename
* argument as being deserialized...
*/
private class ShelveOpenCall extends Decoding::Range, FileSystemAccess::Range,
DataFlow::CallCfgNode
{
ShelveOpenCall() { this = API::moduleImport("shelve").getMember("open").getACall() }
override predicate mayExecuteInput() { any() }
override DataFlow::Node getAnInput() {
result in [this.getArg(0), this.getArgByName("filename")]
}
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("filename")]
}
override DataFlow::Node getOutput() { result = this }
override string getFormat() { result = "pickle" }
}
// ---------------------------------------------------------------------------
// popen2
// ---------------------------------------------------------------------------
/** Gets a reference to the `popen2` module (only available in Python 2). */
API::Node popen2() { result = API::moduleImport("popen2") }
/**
* A call to any of the `popen.popen*` functions, or instantiation of a `popen.Popen*` class.
* See https://docs.python.org/2.7/library/popen2.html
*/
private class Popen2PopenCall extends SystemCommandExecution::Range, DataFlow::CallCfgNode {
Popen2PopenCall() {
exists(string name |
name in ["popen2", "popen3", "popen4", "Popen3", "Popen4"] and
this = popen2().getMember(name).getACall()
)
}
override DataFlow::Node getCommand() { result in [this.getArg(0), this.getArgByName("cmd")] }
override predicate isShellInterpreted(DataFlow::Node arg) { arg = this.getCommand() }
}
// ---------------------------------------------------------------------------
// platform
// ---------------------------------------------------------------------------
/** Gets a reference to the `platform` module. */
API::Node platform() { result = API::moduleImport("platform") }
/**
* A call to the `platform.popen` function.
* See https://docs.python.org/2.7/library/platform.html#platform.popen
*/
private class PlatformPopenCall extends SystemCommandExecution::Range, DataFlow::CallCfgNode {
PlatformPopenCall() { this = platform().getMember("popen").getACall() }
override DataFlow::Node getCommand() { result in [this.getArg(0), this.getArgByName("cmd")] }
override predicate isShellInterpreted(DataFlow::Node arg) { arg = this.getCommand() }
}
// ---------------------------------------------------------------------------
// builtins
// ---------------------------------------------------------------------------
/**
* A call to the builtin `exec` function.
* See https://docs.python.org/3/library/functions.html#exec
*/
private class BuiltinsExecCall extends CodeExecution::Range, DataFlow::CallCfgNode {
BuiltinsExecCall() { this = API::builtin("exec").getACall() }
override DataFlow::Node getCode() { result = this.getArg(0) }
}
/**
* A call to the builtin `eval` function.
* See https://docs.python.org/3/library/functions.html#eval
*/
private class BuiltinsEvalCall extends CodeExecution::Range, DataFlow::CallCfgNode {
override CallNode node;
BuiltinsEvalCall() { this = API::builtin("eval").getACall() }
override DataFlow::Node getCode() { result = this.getArg(0) }
}
/** An additional taint step for calls to the builtin function `compile` */
private class BuiltinsCompileCallAdditionalTaintStep extends TaintTracking::AdditionalTaintStep {
override predicate step(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {
exists(DataFlow::CallCfgNode call |
nodeTo = call and
call = API::builtin("compile").getACall() and
nodeFrom in [call.getArg(0), call.getArgByName("source")]
)
}
}
/** Gets a reference to the builtin `open` function */
private API::Node getOpenFunctionRef() {
result = API::builtin("open")
or
// io.open is a special case, since it is an alias for the builtin `open`
result = API::moduleImport("io").getMember("open")
or
// similarly, coecs.open calls the builtin `open`: https://github.com/python/cpython/blob/3.12/Lib/codecs.py#L918
result = API::moduleImport("codecs").getMember("open")
}
/**
* A call to the builtin `open` function.
* See https://docs.python.org/3/library/functions.html#open
*/
private class OpenCall extends FileSystemAccess::Range, Stdlib::FileLikeObject::InstanceSource,
ThreatModelSource::Range, DataFlow::CallCfgNode
{
OpenCall() {
this = getOpenFunctionRef().getACall() and
// when analyzing stdlib code for os.py we wrongly assume that `os.open` is an
// alias of the builtins `open` function
not this instanceof OsFileSystemAccessModeling::OsOpenCall
}
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("file")]
}
override string getThreatModel() { result = "file" }
override string getSourceType() { result = "open()" }
}
/**
* A call to the `io.FileIO` constructor.
* See https://docs.python.org/3/library/io.html#io.FileIO
*/
private class FileIOCall extends FileSystemAccess::Range, API::CallNode {
FileIOCall() { this = API::moduleImport("io").getMember("FileIO").getACall() }
override DataFlow::Node getAPathArgument() { result = this.getParameter(0, "file").asSink() }
}
/**
* A call to the `io.open_code` function.
* See https://docs.python.org/3.11/library/io.html#io.open_code
*/
private class OpenCodeCall extends FileSystemAccess::Range, API::CallNode {
OpenCodeCall() { this = API::moduleImport("io").getMember("open_code").getACall() }
override DataFlow::Node getAPathArgument() { result = this.getParameter(0, "path").asSink() }
}
/** Gets a reference to an open file. */
private DataFlow::TypeTrackingNode openFile(DataFlow::TypeTracker t, FileSystemAccess openCall) {
t.start() and
result = openCall and
(
openCall instanceof OpenCall and
// don't include the open call inside of Path.open in pathlib.py since
// the call to `path_obj.open` is covered by `PathLibOpenCall`.
not exists(Module mod, Class cls, Function func |
openCall.(OpenCall).asCfgNode().getScope() = func and
func.getName() = "open" and
func.getScope() = cls and
cls.getName() = "Path" and
cls.getScope() = mod and
mod.getName() = "pathlib" and
// do allow this call if we're analyzing pathlib.py as part of CPython though
not exists(mod.getFile().getRelativePath())
)
or
openCall instanceof PathLibOpenCall
)
or
exists(DataFlow::TypeTracker t2 | result = openFile(t2, openCall).track(t2, t))
}
/** Gets a reference to an open file. */
private DataFlow::Node openFile(FileSystemAccess openCall) {
openFile(DataFlow::TypeTracker::end(), openCall).flowsTo(result)
}
/** Gets a reference to the `write` or `writelines` method on an open file. */
private DataFlow::TypeTrackingNode writeMethodOnOpenFile(
DataFlow::TypeTracker t, FileSystemAccess openCall
) {
t.startInAttr(["write", "writelines"]) and
result = openFile(openCall)
or
exists(DataFlow::TypeTracker t2 | result = writeMethodOnOpenFile(t2, openCall).track(t2, t))
}
/** Gets a reference to the `write` or `writelines` method on an open file. */
private DataFlow::Node writeMethodOnOpenFile(FileSystemAccess openCall) {
writeMethodOnOpenFile(DataFlow::TypeTracker::end(), openCall).flowsTo(result)
}
/** A call to the `write` or `writelines` method on an opened file, such as `open("foo", "w").write(...)`. */
private class WriteCallOnOpenFile extends FileSystemWriteAccess::Range, DataFlow::CallCfgNode {
FileSystemAccess openCall;
WriteCallOnOpenFile() { this.getFunction() = writeMethodOnOpenFile(openCall) }
override DataFlow::Node getAPathArgument() {
// best effort attempt to give the path argument, that was initially given to the
// `open` call.
result = openCall.getAPathArgument()
}
override DataFlow::Node getADataNode() { result in [this.getArg(0), this.getArgByName("data")] }
}
/**
* An exec statement (only Python 2).
* See https://docs.python.org/2/reference/simple_stmts.html#the-exec-statement.
*/
private class ExecStatement extends CodeExecution::Range {
ExecStatement() {
// since there are no DataFlow::Nodes for a Statement, we can't do anything like
// `this = any(Exec exec)`
this.asExpr() = any(Exec exec).getBody()
}
override DataFlow::Node getCode() { result = this }
}
// ---------------------------------------------------------------------------
// base64
// ---------------------------------------------------------------------------
/** Gets a reference to the `base64` module. */
API::Node base64() { result = API::moduleImport("base64") }
/** A call to any of the encode functions in the `base64` module. */
private class Base64EncodeCall extends Encoding::Range, DataFlow::CallCfgNode {
string name;
Base64EncodeCall() {
name in [
"b64encode", "standard_b64encode", "urlsafe_b64encode", "b32encode", "b16encode",
"encodestring", "a85encode", "b85encode", "encodebytes", "b32hexencode"
] and
this = base64().getMember(name).getACall()
}
override DataFlow::Node getAnInput() { result = this.getArg(0) }
override DataFlow::Node getOutput() { result = this }
override string getFormat() {
name in [
"b64encode", "standard_b64encode", "urlsafe_b64encode", "encodestring", "encodebytes"
] and
result = "Base64"
or
name in ["b32encode", "b32hexencode"] and result = "Base32"
or
name = "b16encode" and result = "Base16"
or
name = "a85encode" and result = "Ascii85"
or
name = "b85encode" and result = "Base85"
}
}
/** A call to any of the decode functions in the `base64` module. */
private class Base64DecodeCall extends Decoding::Range, DataFlow::CallCfgNode {
string name;
Base64DecodeCall() {
name in [
"b64decode", "standard_b64decode", "urlsafe_b64decode", "b32decode", "b16decode",
"decodestring", "a85decode", "b85decode", "decodebytes", "b32hexdecode"
] and
this = base64().getMember(name).getACall()
}
override predicate mayExecuteInput() { none() }
override DataFlow::Node getAnInput() { result = this.getArg(0) }
override DataFlow::Node getOutput() { result = this }
override string getFormat() {
name in [
"b64decode", "standard_b64decode", "urlsafe_b64decode", "decodestring", "decodebytes"
] and
result = "Base64"
or
name in ["b32decode", "b32hexdecode"] and result = "Base32"
or
name = "b16decode" and result = "Base16"
or
name = "a85decode" and result = "Ascii85"
or
name = "b85decode" and result = "Base85"
}
}
// ---------------------------------------------------------------------------
// json
// ---------------------------------------------------------------------------
/** Gets a reference to the `json` module. */
API::Node json() { result = API::moduleImport("json") }
/**
* A call to `json.loads`
* See https://docs.python.org/3/library/json.html#json.loads
*/
private class JsonLoadsCall extends Decoding::Range, DataFlow::CallCfgNode {
JsonLoadsCall() { this = json().getMember("loads").getACall() }
override predicate mayExecuteInput() { none() }
override DataFlow::Node getAnInput() { result in [this.getArg(0), this.getArgByName("s")] }
override DataFlow::Node getOutput() { result = this }
override string getFormat() { result = "JSON" }
}
/**
* A call to `json.load`
* See https://docs.python.org/3/library/json.html#json.load
*/
private class JsonLoadCall extends Decoding::Range, DataFlow::CallCfgNode {
JsonLoadCall() { this = json().getMember("load").getACall() }
override predicate mayExecuteInput() { none() }
override DataFlow::Node getAnInput() { result in [this.getArg(0), this.getArgByName("fp")] }
override DataFlow::Node getOutput() { result = this }
override string getFormat() { result = "JSON" }
}
/**
* A call to `json.dumps`
* See https://docs.python.org/3/library/json.html#json.dumps
*/
private class JsonDumpsCall extends Encoding::Range, DataFlow::CallCfgNode {
JsonDumpsCall() { this = json().getMember("dumps").getACall() }
override DataFlow::Node getAnInput() { result in [this.getArg(0), this.getArgByName("obj")] }
override DataFlow::Node getOutput() { result = this }
override string getFormat() { result = "JSON" }
}
/**
* A call to `json.dump`
* See https://docs.python.org/3/library/json.html#json.dump
*/
private class JsonDumpCall extends Encoding::Range, DataFlow::CallCfgNode {
JsonDumpCall() { this = json().getMember("dump").getACall() }
override DataFlow::Node getAnInput() { result in [this.getArg(0), this.getArgByName("obj")] }
override DataFlow::Node getOutput() {
result.(DataFlow::PostUpdateNode).getPreUpdateNode() in [
this.getArg(1), this.getArgByName("fp")
]
}
override string getFormat() { result = "JSON" }
}
// ---------------------------------------------------------------------------
// cgi
// ---------------------------------------------------------------------------
/** Gets a reference to the `cgi` module. */
API::Node cgi() { result = API::moduleImport("cgi") }
/** Provides models for the `cgi` module. */
module Cgi {
/**
* Provides models for the `cgi.FieldStorage` class
*
* See https://docs.python.org/3/library/cgi.html.
*/
module FieldStorage {
/** Gets a reference to the `cgi.FieldStorage` class or any subclass. */
API::Node subclassRef() {
result = API::moduleImport("cgi").getMember("FieldStorage").getASubclass*()
or
result = ModelOutput::getATypeNode("cgi.FieldStorage~Subclass").getASubclass*()
}
/**
* A source of instances of `cgi.FieldStorage`, extend this class to model new instances.
*
* This can include instantiations of the class, return values from function
* calls, or a special parameter that will be set when functions are called by an external
* library.
*
* Use the predicate `FieldStorage::instance()` to get references to instances of `cgi.FieldStorage`.
*/
abstract class InstanceSource extends DataFlow::Node { }
/**
* A direct instantiation of `cgi.FieldStorage`.
*
* We currently consider ALL instantiations to be `RemoteFlowSource`. This seems
* reasonable since it's used to parse form data for incoming POST requests, but
* if it turns out to be a problem, we'll have to refine.
*/
private class ClassInstantiation extends InstanceSource, RemoteFlowSource::Range,
DataFlow::CallCfgNode
{
ClassInstantiation() { this = subclassRef().getACall() }
override string getSourceType() { result = "cgi.FieldStorage" }
}
/** Gets a reference to an instance of `cgi.FieldStorage`. */
API::Node instance() { result = subclassRef().getReturn() }
/** Gets a reference to the `getvalue` method on a `cgi.FieldStorage` instance. */
API::Node getvalueRef() { result = instance().getMember("getvalue") }
/** Gets a reference to the result of calling the `getvalue` method on a `cgi.FieldStorage` instance. */
API::Node getvalueResult() { result = getvalueRef().getReturn() }
/** Gets a reference to the `getfirst` method on a `cgi.FieldStorage` instance. */
API::Node getfirstRef() { result = instance().getMember("getfirst") }
/** Gets a reference to the result of calling the `getfirst` method on a `cgi.FieldStorage` instance. */
API::Node getfirstResult() { result = getfirstRef().getReturn() }
/** Gets a reference to the `getlist` method on a `cgi.FieldStorage` instance. */
API::Node getlistRef() { result = instance().getMember("getlist") }
/** Gets a reference to the result of calling the `getlist` method on a `cgi.FieldStorage` instance. */
API::Node getlistResult() { result = getlistRef().getReturn() }
/** Gets a reference to a list of fields. */
API::Node fieldList() {
result = getlistResult()
or
result = getvalueResult()
or
result = instance().getASubscript()
}
/** Gets a reference to a field. */
API::Node field() {
result = getfirstResult()
or
result = getvalueResult()
or
result = [instance(), fieldList()].getASubscript()
}
private class AdditionalTaintStep extends TaintTracking::AdditionalTaintStep {
override predicate step(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {
// Methods
nodeFrom = nodeTo.(DataFlow::AttrRead).getObject() and
nodeFrom = instance().getAValueReachableFromSource() and
nodeTo = [getvalueRef(), getfirstRef(), getlistRef()].getAValueReachableFromSource()
or
nodeFrom.asCfgNode() = nodeTo.asCfgNode().(CallNode).getFunction() and
(
nodeFrom = getvalueRef().getAValueReachableFromSource() and
nodeTo = getvalueResult().asSource()
or
nodeFrom = getfirstRef().getAValueReachableFromSource() and
nodeTo = getfirstResult().asSource()
or
nodeFrom = getlistRef().getAValueReachableFromSource() and
nodeTo = getlistResult().asSource()
)
or
// Indexing
nodeFrom in [
instance().getAValueReachableFromSource(), fieldList().getAValueReachableFromSource()
] and
nodeTo.asCfgNode().(SubscriptNode).getObject() = nodeFrom.asCfgNode()
or
// Attributes on Field
nodeFrom = field().getAValueReachableFromSource() and
exists(DataFlow::AttrRead read | nodeTo = read and read.getObject() = nodeFrom |
read.getAttributeName() in ["value", "file", "filename"]
)
}
}
}
}
// ---------------------------------------------------------------------------
// BaseHTTPServer (Python 2 only)
// ---------------------------------------------------------------------------
// ---------------------------------------------------------------------------
// SimpleHTTPServer (Python 2 only)
// ---------------------------------------------------------------------------
// ---------------------------------------------------------------------------
// CGIHTTPServer (Python 2 only)
// ---------------------------------------------------------------------------
// ---------------------------------------------------------------------------
// http (Python 3 only)
// ---------------------------------------------------------------------------
/**
* Provides models for the `BaseHTTPRequestHandler` class and subclasses.
*
* See
* - https://docs.python.org/3.9/library/http.server.html#http.server.BaseHTTPRequestHandler
* - https://docs.python.org/2.7/library/basehttpserver.html#BaseHTTPServer.BaseHTTPRequestHandler
*/
module BaseHttpRequestHandler {
/** Gets a reference to the `BaseHttpRequestHandler` class or any subclass. */
API::Node subclassRef() {
result =
[
// Python 2
API::moduleImport("BaseHTTPServer").getMember("BaseHTTPRequestHandler"),
API::moduleImport("SimpleHTTPServer").getMember("SimpleHTTPRequestHandler"),
API::moduleImport("CGIHTTPServer").getMember("CGIHTTPRequestHandler"),
// Python 3
API::moduleImport("http").getMember("server").getMember("BaseHTTPRequestHandler"),
API::moduleImport("http").getMember("server").getMember("SimpleHTTPRequestHandler"),
API::moduleImport("http").getMember("server").getMember("CGIHTTPRequestHandler"),
].getASubclass*()
or
result =
ModelOutput::getATypeNode("http.server.BaseHTTPRequestHandler~Subclass").getASubclass*()
}
/** A HttpRequestHandler class definition (most likely in project code). */
class HttpRequestHandlerClassDef extends Class {
HttpRequestHandlerClassDef() { this.getParent() = subclassRef().asSource().asExpr() }
}
/**
* A source of instances of the `BaseHTTPRequestHandler` class or any subclass, extend this class to model new instances.
*
* This can include instantiations of the class, return values from function
* calls, or a special parameter that will be set when functions are called by an external
* library.
*
* Use the predicate `classname::instance()` to get references to instances of the `BaseHTTPRequestHandler` class or any subclass.
*/
abstract class InstanceSource extends DataFlow::Node { }
/** The `self` parameter in a method on the `BaseHttpRequestHandler` class or any subclass. */
private class SelfParam extends InstanceSource, RemoteFlowSource::Range, DataFlow::ParameterNode
{
SelfParam() {
exists(HttpRequestHandlerClassDef cls | cls.getAMethod().getArg(0) = this.getParameter())
}
override string getSourceType() { result = "stdlib HTTPRequestHandler" }
}
/** Gets a reference to an instance of the `BaseHttpRequestHandler` class or any subclass. */
private DataFlow::TypeTrackingNode instance(DataFlow::TypeTracker t) {
t.start() and
result instanceof InstanceSource
or
exists(DataFlow::TypeTracker t2 | result = instance(t2).track(t2, t))
}
/** Gets a reference to an instance of the `BaseHttpRequestHandler` class or any subclass. */
DataFlow::Node instance() { instance(DataFlow::TypeTracker::end()).flowsTo(result) }
/** A call to a method that writes to a response header. */
private class HeaderWriteCall extends Http::Server::ResponseHeaderWrite::Range,
DataFlow::MethodCallNode
{
HeaderWriteCall() { this.calls(instance(), "send_header") }
override DataFlow::Node getNameArg() { result = this.getArg(0) }
override DataFlow::Node getValueArg() { result = this.getArg(1) }
override predicate nameAllowsNewline() { any() }
override predicate valueAllowsNewline() { any() }
}
private class AdditionalTaintStep extends TaintTracking::AdditionalTaintStep {
override predicate step(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {
nodeFrom = instance() and
exists(DataFlow::AttrRead read | nodeTo = read and read.getObject() = nodeFrom |
read.getAttributeName() in [
// str
"requestline", "path",
// by default dict-like http.client.HTTPMessage, which is a subclass of email.message.Message
// see https://docs.python.org/3.9/library/email.compat32-message.html#email.message.Message
// TODO: Implement custom methods (at least `get_all`, `as_bytes`, `as_string`)
"headers",
// file-like
"rfile"
]
)
}
}
/** An `HttpMessage` instance that originates from a `BaseHttpRequestHandler` instance. */
private class BaseHttpRequestHandlerHeadersInstances extends Stdlib::HttpMessage::InstanceSource
{
BaseHttpRequestHandlerHeadersInstances() {
this.(DataFlow::AttrRead).accesses(instance(), "headers")
}
}
/** A file-like object that originates from a `BaseHttpRequestHandler` instance. */
private class BaseHttpRequestHandlerFileLikeObjectInstances extends Stdlib::FileLikeObject::InstanceSource
{
BaseHttpRequestHandlerFileLikeObjectInstances() {
this.(DataFlow::AttrRead).accesses(instance(), "rfile")
}
}
/**
* The entry-point for handling a request with a `BaseHTTPRequestHandler` subclass.
*
* Not essential for any functionality, but provides a consistent modeling.
*/
private class RequestHandlerFunc extends Http::Server::RequestHandler::Range {
RequestHandlerFunc() {
this = any(HttpRequestHandlerClassDef cls).getAMethod() and
this.getName() = "do_" + Http::httpVerb()
}
override Parameter getARoutedParameter() { none() }
override string getFramework() { result = "Stdlib" }
}
}
// ---------------------------------------------------------------------------
// wsgiref.simple_server
// ---------------------------------------------------------------------------
/** Provides models for the `wsgiref.simple_server` module. */
module WsgirefSimpleServer {
API::Node subclassRef() {
result =
API::moduleImport("wsgiref")
.getMember("simple_server")
.getMember("WSGIServer")
.getASubclass*()
or
result =
ModelOutput::getATypeNode("wsgiref.simple_server.WSGIServer~Subclass").getASubclass*()
}
class WsgiServerSubclass extends Class, SelfRefMixin {
WsgiServerSubclass() { this.getParent() = subclassRef().asSource().asExpr() }
}
/**
* A function that was passed to the `set_app` method of a
* `wsgiref.simple_server.WSGIServer` instance.
*
* See https://docs.python.org/3.10/library/wsgiref.html#wsgiref.simple_server.WSGIServer.set_app
*
* See https://github.com/python/cpython/blob/b567b9d74bd9e476a3027335873bb0508d6e450f/Lib/wsgiref/handlers.py#L137
* for how a request is processed and given to an application.
*/
class WsgirefSimpleServerApplication extends Http::Server::RequestHandler::Range {
boolean validator;
WsgirefSimpleServerApplication() {
exists(DataFlow::Node appArg, DataFlow::CallCfgNode setAppCall |
(
setAppCall =
WsgirefSimpleServer::subclassRef().getReturn().getMember("set_app").getACall() and
validator = false
or
setAppCall
.(DataFlow::MethodCallNode)
.calls(any(WsgiServerSubclass cls).getASelfRef(), "set_app") and
validator = false
or
// assume an application that is passed to `wsgiref.validate.validator` is eventually passed to `set_app`
setAppCall =
API::moduleImport("wsgiref").getMember("validate").getMember("validator").getACall() and
validator = true
) and
appArg in [setAppCall.getArg(0), setAppCall.getArgByName("application")]
or
// `make_server` calls `set_app`
setAppCall =
API::moduleImport("wsgiref")
.getMember("simple_server")
.getMember("make_server")
.getACall() and
appArg in [setAppCall.getArg(2), setAppCall.getArgByName("app")] and
validator = false
|
appArg = poorMansFunctionTracker(this)
)
}
override Parameter getARoutedParameter() { none() }
override string getFramework() { result = "Stdlib: wsgiref.simple_server application" }
/** Holds if this simple server application was passed to `wsgiref.validate.validator`. */
predicate isValidated() { validator = true }
}
/**
* The parameter of a `WsgirefSimpleServerApplication` that takes the WSGI environment
* when processing a request.
*
* See https://docs.python.org/3.10/library/wsgiref.html#wsgiref.simple_server.WSGIRequestHandler.get_environ
*/
class WsgiEnvirontParameter extends RemoteFlowSource::Range, DataFlow::ParameterNode {
WsgiEnvirontParameter() {
exists(WsgirefSimpleServerApplication func |
if func.isMethod()
then this.getParameter() = func.getArg(1)
else this.getParameter() = func.getArg(0)
)
}
override string getSourceType() {
result = "Stdlib: wsgiref.simple_server application: WSGI environment parameter"
}
}
/**
* Gets a reference to the parameter of a `WsgirefSimpleServerApplication` that
* takes the `start_response` function.
*
* See https://github.com/python/cpython/blob/b567b9d74bd9e476a3027335873bb0508d6e450f/Lib/wsgiref/handlers.py#L225-L252
*/
private DataFlow::TypeTrackingNode startResponse(DataFlow::TypeTracker t) {
t.start() and
exists(WsgirefSimpleServerApplication func |
if func.isMethod()
then result.(DataFlow::ParameterNode).getParameter() = func.getArg(2)
else result.(DataFlow::ParameterNode).getParameter() = func.getArg(1)
)
or
exists(DataFlow::TypeTracker t2 | result = startResponse(t2).track(t2, t))
}
/**
* Gets a reference to the parameter of a `WsgirefSimpleServerApplication` that
* takes the `start_response` function.
*
* See https://github.com/python/cpython/blob/b567b9d74bd9e476a3027335873bb0508d6e450f/Lib/wsgiref/handlers.py#L225-L252
*/
DataFlow::Node startResponse() { startResponse(DataFlow::TypeTracker::end()).flowsTo(result) }
/**
* Gets a reference to the `write` function (that will write data to the response),
* which is the return value from calling the `start_response` function.
*
* See https://github.com/python/cpython/blob/b567b9d74bd9e476a3027335873bb0508d6e450f/Lib/wsgiref/handlers.py#L225-L252
*/
private DataFlow::TypeTrackingNode writeFunction(DataFlow::TypeTracker t) {
t.start() and
result.(DataFlow::CallCfgNode).getFunction() = startResponse()
or
exists(DataFlow::TypeTracker t2 | result = writeFunction(t2).track(t2, t))
}
/**
* Gets a reference to the `write` function (that will write data to the response),
* which is the return value from calling the `start_response` function.
*
* See https://github.com/python/cpython/blob/b567b9d74bd9e476a3027335873bb0508d6e450f/Lib/wsgiref/handlers.py#L225-L252
*/
DataFlow::Node writeFunction() { writeFunction(DataFlow::TypeTracker::end()).flowsTo(result) }
/**
* A call to the `write` function.
*
* See https://github.com/python/cpython/blob/b567b9d74bd9e476a3027335873bb0508d6e450f/Lib/wsgiref/handlers.py#L276
*/
class WsgirefSimpleServerApplicationWriteCall extends Http::Server::HttpResponse::Range,
DataFlow::CallCfgNode
{
WsgirefSimpleServerApplicationWriteCall() { this.getFunction() = writeFunction() }
override DataFlow::Node getBody() { result in [this.getArg(0), this.getArgByName("data")] }
override DataFlow::Node getMimetypeOrContentTypeArg() { none() }
override string getMimetypeDefault() { none() }
}
/**
* A return from a `WsgirefSimpleServerApplication`, which is included in the response body.
*/
class WsgirefSimpleServerApplicationReturn extends Http::Server::HttpResponse::Range,
DataFlow::CfgNode
{
WsgirefSimpleServerApplicationReturn() {
exists(WsgirefSimpleServerApplication requestHandler |
node = requestHandler.getAReturnValueFlowNode()
)
}
override DataFlow::Node getBody() { result = this }
override DataFlow::Node getMimetypeOrContentTypeArg() { none() }
override string getMimetypeDefault() { none() }
}
/**
* Provides models for the `wsgiref.headers.Headers` class
*
* See https://docs.python.org/3/library/wsgiref.html#module-wsgiref.headers.
*/
module Headers {
/** Gets a reference to the `wsgiref.headers.Headers` class. */
API::Node classRef() {
result = API::moduleImport("wsgiref").getMember("headers").getMember("Headers")
or
result = ModelOutput::getATypeNode("wsgiref.headers.Headers~Subclass").getASubclass*()
}
/** Gets a reference to an instance of `wsgiref.headers.Headers`. */
private DataFlow::TypeTrackingNode instance(DataFlow::TypeTracker t) {
t.start() and
result = classRef().getACall()
or
exists(DataFlow::TypeTracker t2 | result = instance(t2).track(t2, t))
}
/** Gets a reference to an instance of `wsgiref.headers.Headers`. */
DataFlow::Node instance() { instance(DataFlow::TypeTracker::end()).flowsTo(result) }
/** Holds if there exists an application that is validated by `wsgiref.validate.validator`. */
private predicate existsValidatedApplication() {
exists(WsgirefSimpleServerApplication app | app.isValidated())
}
/** A class instantiation of `wsgiref.headers.Headers`, conidered as a write to a response header. */
private class WsgirefHeadersInstantiation extends Http::Server::ResponseHeaderBulkWrite::Range,
DataFlow::CallCfgNode
{
WsgirefHeadersInstantiation() { this = classRef().getACall() }
override DataFlow::Node getBulkArg() {
result = [this.getArg(0), this.getArgByName("headers")]
}
// TODO: These checks perhaps could be made more precise.
override predicate nameAllowsNewline() { not existsValidatedApplication() }
override predicate valueAllowsNewline() { not existsValidatedApplication() }
}
/** A call to a method that writes to a response header. */
private class HeaderWriteCall extends Http::Server::ResponseHeaderWrite::Range,
DataFlow::MethodCallNode
{
HeaderWriteCall() {
this.calls(instance(), ["add_header", "set", "setdefault", "__setitem__"])
}
override DataFlow::Node getNameArg() { result = this.getArg(0) }
override DataFlow::Node getValueArg() { result = this.getArg(1) }
// TODO: These checks perhaps could be made more precise.
override predicate nameAllowsNewline() { not existsValidatedApplication() }
override predicate valueAllowsNewline() { not existsValidatedApplication() }
}
/** A dict-like write to a response header. */
private class HeaderWriteSubscript extends Http::Server::ResponseHeaderWrite::Range,
DataFlow::Node
{
DataFlow::Node name;
DataFlow::Node value;
HeaderWriteSubscript() {
exists(SubscriptNode subscript |
this.asCfgNode() = subscript and
value.asCfgNode() = subscript.(DefinitionNode).getValue() and
name.asCfgNode() = subscript.getIndex() and
subscript.getObject() = instance().asCfgNode()
)
}
override DataFlow::Node getNameArg() { result = name }
override DataFlow::Node getValueArg() { result = value }
// TODO: These checks perhaps could be made more precise.
override predicate nameAllowsNewline() { not existsValidatedApplication() }
override predicate valueAllowsNewline() { not existsValidatedApplication() }
}
/**
* A call to a `start_response` function that sets the response headers.
*/
private class WsgirefSimpleServerSetHeaders extends Http::Server::ResponseHeaderBulkWrite::Range,
DataFlow::CallCfgNode
{
WsgirefSimpleServerSetHeaders() { this.getFunction() = startResponse() }
override DataFlow::Node getBulkArg() {
result = [this.getArg(1), this.getArgByName("headers")]
}
// TODO: These checks perhaps could be made more precise.
override predicate nameAllowsNewline() { not existsValidatedApplication() }
override predicate valueAllowsNewline() { not existsValidatedApplication() }
}
}
}
// ---------------------------------------------------------------------------
// http.client (Python 3)
// httplib (Python 2)
// ---------------------------------------------------------------------------
/**
* Provides models for the `http.client.HTTPConnection` and `HTTPSConnection` classes
*
* See
* - https://docs.python.org/3.10/library/http.client.html#http.client.HTTPConnection
* - https://docs.python.org/3.10/library/http.client.html#http.client.HTTPSConnection
* - https://docs.python.org/2.7/library/httplib.html#httplib.HTTPConnection
* - https://docs.python.org/2.7/library/httplib.html#httplib.HTTPSConnection
*/
module HttpConnection {
/** Gets a reference to the `http.client.HttpConnection` class. */
API::Node classRef() {
exists(string className | className in ["HTTPConnection", "HTTPSConnection"] |
// Python 3
result = API::moduleImport("http").getMember("client").getMember(className)
or
// Python 2
result = API::moduleImport("httplib").getMember(className)
or
result =
API::moduleImport("six").getMember("moves").getMember("http_client").getMember(className)
)
or
result = ModelOutput::getATypeNode("http.client.HTTPConnection~Subclass").getASubclass*()
}
/**
* A source of instances of `http.client.HTTPConnection`, extend this class to model new instances.
*
* This can include instantiations of the class, return values from function
* calls, or a special parameter that will be set when functions are called by an external
* library.
*
* Use the predicate `HTTPConnection::instance()` to get references to instances of `http.client.HTTPConnection`.
*/
abstract class InstanceSource extends DataFlow::LocalSourceNode {
/** Gets the argument that specified the host, if any. */
abstract DataFlow::Node getHostArgument();
}
/** A direct instantiation of `http.client.HttpConnection`. */
private class ClassInstantiation extends InstanceSource, DataFlow::CallCfgNode {
ClassInstantiation() { this = classRef().getACall() }
override DataFlow::Node getHostArgument() {
result in [this.getArg(0), this.getArgByName("host")]
}
}
/**
* Gets a reference to an instance of `http.client.HTTPConnection`,
* that was instantiated with host argument `hostArg`.
*/
private DataFlow::TypeTrackingNode instance(DataFlow::TypeTracker t, DataFlow::Node hostArg) {
t.start() and
hostArg = result.(InstanceSource).getHostArgument()
or
exists(DataFlow::TypeTracker t2 | result = instance(t2, hostArg).track(t2, t))
}
/**
* Gets a reference to an instance of `http.client.HTTPConnection`,
* that was instantiated with host argument `hostArg`.
*/
DataFlow::Node instance(DataFlow::Node hostArg) {
instance(DataFlow::TypeTracker::end(), hostArg).flowsTo(result)
}
/** A method call on a HttpConnection that sends off a request */
private class RequestCall extends Http::Client::Request::Range instanceof DataFlow::MethodCallNode
{
RequestCall() { this.calls(instance(_), ["request", "_send_request", "putrequest"]) }
DataFlow::Node getUrlArg() { result in [super.getArg(1), super.getArgByName("url")] }
override DataFlow::Node getAUrlPart() {
result = this.getUrlArg()
or
super.getObject() = instance(result)
}
override string getFramework() { result = "http.client.HTTP[S]Connection" }
override predicate disablesCertificateValidation(
DataFlow::Node disablingNode, DataFlow::Node argumentOrigin
) {
// TODO: Proper alerting of insecure verification settings on SSLContext.
// Because that is not restricted to HTTP[S]Connection usage, we need something
// more general, and I would like to tackle that in future PR.
none()
}
}
/** A call to the `getresponse` method. */
private class HttpConnectionGetResponseCall extends DataFlow::MethodCallNode,
HttpResponse::InstanceSource
{
HttpConnectionGetResponseCall() { this.calls(instance(_), "getresponse") }
}
/**
* Extra taint propagation for `http.client.HTTPConnection`,
* to ensure that responses to user-controlled URL are tainted.
*/
private class AdditionalTaintStep extends TaintTracking::AdditionalTaintStep {
override predicate step(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {
// constructor
exists(InstanceSource instanceSource |
nodeFrom = instanceSource.getHostArgument() and
nodeTo = instanceSource
)
or
// a request method
exists(RequestCall call |
nodeFrom = call.getUrlArg() and
nodeTo.(DataFlow::PostUpdateNode).getPreUpdateNode() =
call.(DataFlow::MethodCallNode).getObject()
)
or
// `getresponse` call
exists(HttpConnectionGetResponseCall call |
nodeFrom = call.getObject() and
nodeTo = call
)
}
}
}
/**
* Provides models for the `http.client.HTTPResponse` class
*
* See
* - https://docs.python.org/3.10/library/http.client.html#httpresponse-objects
* - https://docs.python.org/3/library/http.client.html#http.client.HTTPResponse.
*/
module HttpResponse {
/** Gets a reference to the `http.client.HttpResponse` class. */
API::Node classRef() {
result = API::moduleImport("http").getMember("client").getMember("HTTPResponse")
or
result = ModelOutput::getATypeNode("http.client.HTTPResponse~Subclass").getASubclass*()
}
/**
* A source of instances of `http.client.HTTPResponse`, extend this class to model new instances.
*
* A `http.client.HTTPResponse` is itself a file-like object.
*
* This can include instantiations of the class, return values from function
* calls, or a special parameter that will be set when functions are called by an external
* library.
*
* Use the predicate `HTTPResponse::instance()` to get references to instances of `http.client.HTTPResponse`.
*/
abstract class InstanceSource extends Stdlib::FileLikeObject::InstanceSource,
DataFlow::LocalSourceNode
{ }
/** A direct instantiation of `http.client.HttpResponse`. */
private class ClassInstantiation extends InstanceSource, DataFlow::CallCfgNode {
ClassInstantiation() { this = classRef().getACall() }
}
/** Gets a reference to an instance of `http.client.HttpResponse`. */
private DataFlow::TypeTrackingNode instance(DataFlow::TypeTracker t) {
t.start() and
result instanceof InstanceSource
or
exists(DataFlow::TypeTracker t2 | result = instance(t2).track(t2, t))
}
/** Gets a reference to an instance of `http.client.HttpResponse`. */
DataFlow::Node instance() { instance(DataFlow::TypeTracker::end()).flowsTo(result) }
/**
* Taint propagation for `http.client.HTTPResponse`.
*/
private class InstanceTaintSteps extends InstanceTaintStepsHelper {
InstanceTaintSteps() { this = "http.client.HTTPResponse" }
override DataFlow::Node getInstance() { result = instance() }
override string getAttributeName() { result in ["headers", "msg", "reason", "url"] }
override string getMethodName() { result in ["getheader", "getheaders", "info", "geturl",] }
override string getAsyncMethodName() { none() }
}
/** An attribute read that is a HttpMessage instance. */
private class HttpMessageInstances extends Stdlib::HttpMessage::InstanceSource {
HttpMessageInstances() {
this.(DataFlow::AttrRead).accesses(instance(), ["headers", "msg"])
or
this.(DataFlow::MethodCallNode).calls(instance(), "info")
}
}
}
// ---------------------------------------------------------------------------
// sqlite3
// ---------------------------------------------------------------------------
/**
* A model of sqlite3 as a module that implements PEP 249, providing ways to execute SQL statements
* against a database.
*
* See https://devdocs.io/python~3.9/library/sqlite3
* https://github.com/python/cpython/blob/3.11/Lib/sqlite3/dbapi2.py
*/
class Sqlite3 extends PEP249::PEP249ModuleApiNode {
Sqlite3() {
this = API::moduleImport("sqlite3")
or
this = API::moduleImport("sqlite3").getMember("dbapi2")
}
}
// ---------------------------------------------------------------------------
// pathlib
// ---------------------------------------------------------------------------
/** Gets a reference to the `pathlib` module. */
private API::Node pathlib() { result = API::moduleImport("pathlib") }
/**
* Gets a name of a constructor for a `pathlib.Path` object.
* We include the pure paths, as they can be "exported" (say with `as_posix`) and then used to access the underlying file system.
*/
private string pathlibPathConstructor() {
result in ["Path", "PurePath", "PurePosixPath", "PureWindowsPath", "PosixPath", "WindowsPath"]
}
/**
* Gets a name of an attribute of a `pathlib.Path` object that is also a `pathlib.Path` object.
*/
private string pathlibPathAttribute() { result = "parent" }
/**
* Gets a name of a method of a `pathlib.Path` object that returns a `pathlib.Path` object.
*/
private string pathlibPathMethod() {
result in ["absolute", "relative_to", "rename", "replace", "resolve"]
}
/**
* Gets a name of a method of a `pathlib.Path` object that modifies a `pathlib.Path` object based on new data.
*/
private string pathlibPathInjection() {
result in ["joinpath", "with_name", "with_stem", "with_suffix"]
}
/**
* Gets a name of an attribute of a `pathlib.Path` object that exports information about the `pathlib.Path` object.
*/
private string pathlibPathAttributeExport() {
result in ["drive", "root", "anchor", "name", "suffix", "stem"]
}
/**
* Gets a name of a method of a `pathlib.Path` object that exports information about the `pathlib.Path` object.
*/
private string pathlibPathMethodExport() { result in ["as_posix", "as_uri"] }
/**
* Flow for attributes and methods that return a `pathlib.Path` object.
*/
private predicate pathlibPathStep(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {
exists(DataFlow::AttrRead returnsPath |
(
// attribute access
returnsPath.getAttributeName() = pathlibPathAttribute() and
nodeTo = returnsPath
or
// method call
returnsPath.getAttributeName() = pathlibPathMethod() and
returnsPath
.(DataFlow::LocalSourceNode)
.flowsTo(nodeTo.(DataFlow::CallCfgNode).getFunction())
) and
nodeFrom = returnsPath.getObject()
)
}
/**
* Gets a reference to a `pathlib.Path` object.
* This type tracker makes the monomorphic API use assumption.
*/
private DataFlow::TypeTrackingNode pathlibPath(DataFlow::TypeTracker t) {
// Type construction
t.start() and
result = pathlib().getMember(pathlibPathConstructor()).getACall()
or
// Type-preserving step
exists(DataFlow::Node nodeFrom, DataFlow::TypeTracker t2 |
pathlibPath(t2).flowsTo(nodeFrom) and
t2.end()
|
t.start() and
pathlibPathStep(nodeFrom, result)
)
or
// Data injection
// Special handling of the `/` operator
exists(BinaryExprNode slash, DataFlow::Node pathOperand, DataFlow::TypeTracker t2 |
slash.getOp() instanceof Div and
pathOperand.asCfgNode() = slash.getAnOperand() and
pathlibPath(t2).flowsTo(pathOperand) and
t2.end()
|
t.start() and
result.asCfgNode() = slash
)
or
// standard case
exists(DataFlow::AttrRead returnsPath, DataFlow::TypeTracker t2 |
returnsPath.getAttributeName() = pathlibPathInjection() and
pathlibPath(t2).flowsTo(returnsPath.getObject()) and
t2.end()
|
t.start() and
result.(DataFlow::CallCfgNode).getFunction() = returnsPath
)
or
// Track further
exists(DataFlow::TypeTracker t2 | result = pathlibPath(t2).track(t2, t))
}
/** Gets a reference to a `pathlib.Path` object. */
DataFlow::LocalSourceNode pathlibPath() { result = pathlibPath(DataFlow::TypeTracker::end()) }
/** A file system access from a `pathlib.Path` method call. */
private class PathlibFileAccess extends FileSystemAccess::Range, DataFlow::CallCfgNode {
DataFlow::AttrRead fileAccess;
string attributeName;
PathlibFileAccess() {
attributeName = fileAccess.getAttributeName() and
attributeName in [
"stat", "chmod", "exists", "expanduser", "glob", "group", "is_dir", "is_file", "is_mount",
"is_symlink", "is_socket", "is_fifo", "is_block_device", "is_char_device", "iter_dir",
"lchmod", "lstat", "mkdir", "open", "owner", "read_bytes", "read_text", "readlink",
"rename", "replace", "resolve", "rglob", "rmdir", "samefile", "symlink_to", "touch",
"unlink", "link_to", "write_bytes", "write_text", "hardlink_to"
] and
pathlibPath().flowsTo(fileAccess.getObject()) and
fileAccess.(DataFlow::LocalSourceNode).flowsTo(this.getFunction())
}
override DataFlow::Node getAPathArgument() { result = fileAccess.getObject() }
}
/** A file system write from a `pathlib.Path` method call. */
private class PathlibFileWrites extends PathlibFileAccess, FileSystemWriteAccess::Range {
PathlibFileWrites() { attributeName in ["write_bytes", "write_text"] }
override DataFlow::Node getADataNode() { result in [this.getArg(0), this.getArgByName("data")] }
}
/** A call to the `open` method on a `pathlib.Path` instance. */
private class PathLibOpenCall extends PathlibFileAccess, Stdlib::FileLikeObject::InstanceSource {
PathLibOpenCall() { attributeName = "open" }
}
/**
* A call to the `link_to`, `hardlink_to`, or `symlink_to` method on a `pathlib.Path` instance.
*
* See
* - https://docs.python.org/3/library/pathlib.html#pathlib.Path.link_to
* - https://docs.python.org/3/library/pathlib.html#pathlib.Path.hardlink_to
* - https://docs.python.org/3/library/pathlib.html#pathlib.Path.symlink_to
*/
private class PathLibLinkToCall extends PathlibFileAccess, API::CallNode {
PathLibLinkToCall() { attributeName in ["link_to", "hardlink_to", "symlink_to"] }
override DataFlow::Node getAPathArgument() {
result = super.getAPathArgument()
or
result = this.getParameter(0, "target").asSink()
}
}
/**
* A call to the `replace` or `rename` method on a `pathlib.Path` instance.
*
* See
* - https://docs.python.org/3/library/pathlib.html#pathlib.Path.replace
* - https://docs.python.org/3/library/pathlib.html#pathlib.Path.rename
*/
private class PathLibReplaceCall extends PathlibFileAccess, API::CallNode {
PathLibReplaceCall() { attributeName in ["replace", "rename"] }
override DataFlow::Node getAPathArgument() {
result = super.getAPathArgument()
or
result = this.getParameter(0, "target").asSink()
}
}
/**
* A call to the `samefile` method on a `pathlib.Path` instance.
*
* See https://docs.python.org/3/library/pathlib.html#pathlib.Path.samefile
*/
private class PathLibSameFileCall extends PathlibFileAccess, API::CallNode {
PathLibSameFileCall() { attributeName = "samefile" }
override DataFlow::Node getAPathArgument() {
result = super.getAPathArgument()
or
result = this.getParameter(0, "other_path").asSink()
}
}
/** An additional taint steps for objects of type `pathlib.Path` */
private class PathlibPathTaintStep extends TaintTracking::AdditionalTaintStep {
override predicate step(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {
// Type construction
nodeTo = pathlib().getMember(pathlibPathConstructor()).getACall() and
nodeFrom = nodeTo.(DataFlow::CallCfgNode).getArg(_)
or
// Type preservation
pathlibPath().flowsTo(nodeFrom) and
pathlibPathStep(nodeFrom, nodeTo)
or
// Data injection
pathlibPath().flowsTo(nodeTo) and
(
// Special handling of the `/` operator
exists(BinaryExprNode slash, DataFlow::Node pathOperand |
slash.getOp() instanceof Div and
pathOperand.asCfgNode() = slash.getAnOperand() and
pathlibPath().flowsTo(pathOperand)
|
nodeTo.asCfgNode() = slash and
// Taint can flow either from the left or the right operand as long as one of them is a path.
nodeFrom.asCfgNode() = slash.getAnOperand()
)
or
// standard case
exists(DataFlow::AttrRead augmentsPath |
augmentsPath.getAttributeName() = pathlibPathInjection()
|
augmentsPath
.(DataFlow::LocalSourceNode)
.flowsTo(nodeTo.(DataFlow::CallCfgNode).getFunction()) and
(
// type-preserving call
nodeFrom = augmentsPath.getObject()
or
// data injection
nodeFrom = nodeTo.(DataFlow::CallCfgNode).getArg(_)
)
)
)
or
// Export data from type
pathlibPath().flowsTo(nodeFrom) and
exists(DataFlow::AttrRead exportPath |
// exporting attribute
exportPath.getAttributeName() = pathlibPathAttributeExport() and
nodeTo = exportPath
or
// exporting method
exportPath.getAttributeName() = pathlibPathMethodExport() and
exportPath.(DataFlow::LocalSourceNode).flowsTo(nodeTo.(DataFlow::CallCfgNode).getFunction())
|
nodeFrom = exportPath.getObject()
)
}
}
// ---------------------------------------------------------------------------
// hashlib
// ---------------------------------------------------------------------------
/** Gets a call to `hashlib.new` with `algorithmName` as the first argument. */
private API::CallNode hashlibNewCall(string algorithmName) {
algorithmName =
result.getParameter(0, "name").getAValueReachingSink().asExpr().(StringLiteral).getText() and
result = API::moduleImport("hashlib").getMember("new").getACall()
}
/**
* A hashing operation by supplying initial data when calling the `hashlib.new` function.
*/
class HashlibNewCall extends Cryptography::CryptographicOperation::Range instanceof API::CallNode {
string hashName;
HashlibNewCall() {
this = hashlibNewCall(hashName) and
// we only want to consider it as an cryptographic operation if the input is available
exists(this.getParameter(1, "data"))
}
override DataFlow::Node getInitialization() { result = this }
override Cryptography::CryptographicAlgorithm getAlgorithm() { result.matchesName(hashName) }
override DataFlow::Node getAnInput() { result = super.getParameter(1, "data").asSink() }
override Cryptography::BlockMode getBlockMode() { none() }
}
/**
* A hashing operation by using the `update` method on the result of calling the `hashlib.new` function.
*/
class HashlibNewUpdateCall extends Cryptography::CryptographicOperation::Range instanceof API::CallNode
{
API::CallNode init;
string hashName;
HashlibNewUpdateCall() {
init = hashlibNewCall(hashName) and
this = init.getReturn().getMember("update").getACall()
}
override DataFlow::Node getInitialization() { result = init }
override Cryptography::CryptographicAlgorithm getAlgorithm() { result.matchesName(hashName) }
override DataFlow::Node getAnInput() { result = super.getArg(0) }
override Cryptography::BlockMode getBlockMode() { none() }
}
/** Helper predicate for the `HashLibGenericHashOperation` charpred, to prevent a bad join order. */
pragma[nomagic]
private API::Node hashlibMember(string hashName) {
result = API::moduleImport("hashlib").getMember(hashName) and
hashName != "new"
}
/**
* A hashing operation from the `hashlib` package using one of the predefined classes
* (such as `hashlib.md5`). `hashlib.new` is not included, since it is handled by
* `HashlibNewCall` and `HashlibNewUpdateCall`.
*/
abstract class HashlibGenericHashOperation extends Cryptography::CryptographicOperation::Range instanceof DataFlow::CallCfgNode
{
string hashName;
API::Node hashClass;
bindingset[this]
HashlibGenericHashOperation() { hashClass = hashlibMember(hashName) }
override Cryptography::CryptographicAlgorithm getAlgorithm() { result.matchesName(hashName) }
override Cryptography::BlockMode getBlockMode() { none() }
}
/**
* A hashing operation from the `hashlib` package using one of the predefined classes
* (such as `hashlib.md5`), by calling its' `update` method.
*/
class HashlibHashClassUpdateCall extends HashlibGenericHashOperation {
API::CallNode init;
HashlibHashClassUpdateCall() {
init = hashClass.getACall() and
this = hashClass.getReturn().getMember("update").getACall()
}
override DataFlow::Node getInitialization() { result = init }
override DataFlow::Node getAnInput() { result = this.(DataFlow::CallCfgNode).getArg(0) }
}
/**
* A hashing operation from the `hashlib` package using one of the predefined classes
* (such as `hashlib.md5`), by passing data to when instantiating the class.
*/
class HashlibDataPassedToHashClass extends HashlibGenericHashOperation {
HashlibDataPassedToHashClass() {
// we only want to model calls to classes such as `hashlib.md5()` if initial data
// is passed as an argument
this = hashClass.getACall() and
exists(
[
this.(DataFlow::CallCfgNode).getArg(0),
this.(DataFlow::CallCfgNode).getArgByName("string")
]
)
}
override DataFlow::Node getInitialization() { result = this }
override DataFlow::Node getAnInput() {
result = this.(DataFlow::CallCfgNode).getArg(0)
or
// in Python 3.9, you are allowed to use `hashlib.md5(string=<bytes-like>)`.
result = this.(DataFlow::CallCfgNode).getArgByName("string")
}
}
// ---------------------------------------------------------------------------
// hmac
// ---------------------------------------------------------------------------
abstract class HmacCryptographicOperation extends Cryptography::CryptographicOperation::Range instanceof API::CallNode
{
abstract API::Node getDigestArg();
override Cryptography::CryptographicAlgorithm getAlgorithm() {
exists(string algorithmName | result.matchesName(algorithmName) |
this.getDigestArg().asSink() = hashlibMember(algorithmName).asSource()
or
this.getDigestArg().getAValueReachingSink().asExpr().(StringLiteral).getText() =
algorithmName
)
}
override Cryptography::BlockMode getBlockMode() { none() }
}
API::CallNode getHmacConstructorCall(API::Node digestArg) {
result = API::moduleImport("hmac").getMember(["new", "HMAC"]).getACall() and
digestArg = result.getParameter(2, "digestmod")
}
/**
* A call to `hmac.new`/`hmac.HMAC`.
*
* See https://docs.python.org/3.11/library/hmac.html#hmac.new
*/
class HmacNewCall extends HmacCryptographicOperation {
API::Node digestArg;
HmacNewCall() {
this = getHmacConstructorCall(digestArg) and
// we only want to consider it as an cryptographic operation if the input is available
exists(this.(API::CallNode).getParameter(1, "msg").asSink())
}
override DataFlow::Node getInitialization() { result = this }
override API::Node getDigestArg() { result = digestArg }
override DataFlow::Node getAnInput() {
result = this.(API::CallNode).getParameter(1, "msg").asSink()
}
}
/**
* A call to `.update` on an HMAC object.
*
* See https://docs.python.org/3.11/library/hmac.html#hmac.HMAC.update
*/
class HmacUpdateCall extends HmacCryptographicOperation {
API::CallNode init;
API::Node digestArg;
HmacUpdateCall() {
init = getHmacConstructorCall(digestArg) and
this = init.getReturn().getMember("update").getACall()
}
override DataFlow::Node getInitialization() { result = init }
override API::Node getDigestArg() { result = digestArg }
override DataFlow::Node getAnInput() {
result = this.(API::CallNode).getParameter(0, "msg").asSink()
}
}
/**
* A call to `hmac.digest`.
*
* See https://docs.python.org/3.11/library/hmac.html#hmac.digest
*/
class HmacDigestCall extends HmacCryptographicOperation {
HmacDigestCall() { this = API::moduleImport("hmac").getMember("digest").getACall() }
override DataFlow::Node getInitialization() { result = this }
override API::Node getDigestArg() { result = this.(API::CallNode).getParameter(2, "digest") }
override DataFlow::Node getAnInput() {
result = this.(API::CallNode).getParameter(1, "msg").asSink()
}
}
// ---------------------------------------------------------------------------
// logging
// ---------------------------------------------------------------------------
/**
* A call to one of the logging methods from `logging` or on a `logging.Logger`
* subclass.
*
* See:
* - https://docs.python.org/3.9/library/logging.html#logging.debug
* - https://docs.python.org/3.9/library/logging.html#logging.Logger.debug
*/
class LoggerLogCall extends Logging::Range, DataFlow::CallCfgNode {
/** The argument-index where the message is passed. */
int msgIndex;
LoggerLogCall() {
exists(string method |
method in ["critical", "fatal", "error", "warning", "warn", "info", "debug", "exception"] and
msgIndex = 0
or
method = "log" and
msgIndex = 1
|
this.(DataFlow::MethodCallNode).calls(Stdlib::Logger::instance(), method)
or
this = API::moduleImport("logging").getMember(method).getACall()
)
}
override DataFlow::Node getAnInput() {
result = this.getArgByName(["msg", "extra"])
or
result = this.getArg(any(int i | i >= msgIndex))
}
}
// ---------------------------------------------------------------------------
// re
// ---------------------------------------------------------------------------
/**
* List of methods in the `re` module immediately executing a regular expression.
*
* See https://docs.python.org/3/library/re.html#module-contents
*/
private class RegexExecutionMethod extends string {
RegexExecutionMethod() {
this in ["match", "fullmatch", "search", "split", "findall", "finditer", "sub", "subn"]
}
/** Gets the index of the argument representing the string to be searched by a regex. */
int getStringArgIndex() {
this in ["match", "fullmatch", "search", "split", "findall", "finditer"] and
result = 1
or
this in ["sub", "subn"] and
result = 2
}
}
/**
* A a call to a method from the `re` module immediately executing a regular expression.
*
* See `RegexExecutionMethods`
*/
private class DirectRegexExecution extends DataFlow::CallCfgNode, RegexExecution::Range {
RegexExecutionMethod method;
DirectRegexExecution() { this = API::moduleImport("re").getMember(method).getACall() }
override DataFlow::Node getRegex() { result in [this.getArg(0), this.getArgByName("pattern")] }
override DataFlow::Node getString() {
result in [this.getArg(method.getStringArgIndex()), this.getArgByName("string")]
}
override string getName() { result = "re." + method }
}
API::Node compiledRegex(API::Node regex) {
exists(API::CallNode compilation |
compilation = API::moduleImport("re").getMember("compile").getACall()
|
result = compilation.getReturn() and
regex = compilation.getParameter(0, "pattern")
)
}
/**
* A call on compiled regular expression (obtained via `re.compile`) executing a
* regular expression.
*
* Given the following example:
*
* ```py
* pattern = re.compile(input)
* pattern.match(s)
* ```
*
* This class will identify that `re.compile` compiles `input` and afterwards
* executes `re`'s `match`. As a result, `this` will refer to `pattern.match(s)`
* and `this.getRegexNode()` will return the node for `input` (`re.compile`'s first argument).
*
*
* See `RegexExecutionMethods`
*
* See https://docs.python.org/3/library/re.html#regular-expression-objects
*/
private class CompiledRegexExecution extends DataFlow::MethodCallNode, RegexExecution::Range {
DataFlow::Node regexNode;
RegexExecutionMethod method;
CompiledRegexExecution() {
exists(API::Node regex | regexNode = regex.asSink() |
this.calls(compiledRegex(regex).getAValueReachableFromSource(), method)
)
}
override DataFlow::Node getRegex() { result = regexNode }
override DataFlow::Node getString() {
result in [this.getArg(method.getStringArgIndex() - 1), this.getArgByName("string")]
}
override string getName() { result = "re." + method }
}
/**
* A flow summary for compiled regex objects
*
* See https://docs.python.org/3.11/library/re.html#re-objects
*/
class RePatternSummary extends SummarizedCallable::Range {
RePatternSummary() { this = "re.Pattern" }
override DataFlow::CallCfgNode getACall() {
result = API::moduleImport("re").getMember("compile").getACall()
}
override DataFlow::ArgumentNode getACallback() {
result = API::moduleImport("re").getMember("compile").getAValueReachableFromSource()
}
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
input in ["Argument[0]", "Argument[pattern:]"] and
(
output = "ReturnValue.Attribute[pattern]" and
preservesValue = true
or
output = "ReturnValue" and
preservesValue = false
)
}
}
/**
* A base API node for regular expression functions.
* Either the `re` module or a compiled regular expression.
*/
private API::Node re(boolean compiled) {
result = API::moduleImport("re") and
compiled = false
or
result = any(RePatternSummary c).getACall().(API::CallNode).getReturn() and
compiled = true
}
/**
* A flow summary for methods returning a `re.Match` object
*
* See https://docs.python.org/3/library/re.html#re.Match
*/
class ReMatchSummary extends SummarizedCallable::Range {
ReMatchSummary() { this = ["re.Match", "compiled re.Match"] }
override DataFlow::CallCfgNode getACall() {
exists(API::Node re, boolean compiled |
re = re(compiled) and
(
compiled = false and
this = "re.Match"
or
compiled = true and
this = "compiled re.Match"
)
|
result = re.getMember(["match", "search", "fullmatch"]).getACall()
)
}
override DataFlow::ArgumentNode getACallback() { none() }
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
exists(string arg |
this = "re.Match" and arg = "Argument[1]"
or
this = "compiled re.Match" and arg = "Argument[0]"
|
input in [arg, "Argument[string:]"] and
(
output = "ReturnValue.Attribute[string]" and
preservesValue = true
or
// indexing such as `match[g]` is the same as `match.group(g)`
// since you can index with both integers and strings, we model it as
// both list element and dictionary... a bit of a hack, but no way to model
// subscript operators directly with flow-summaries :|
output in ["ReturnValue.ListElement", "ReturnValue.DictionaryElementAny"] and
preservesValue = false
)
)
or
// regex pattern
(
this = "re.Match" and input in ["Argument[0]", "Argument[pattern:]"]
or
// for compiled regexes, this it is already stored in the `pattern` attribute
this = "compiled re.Match" and input = "Argument[self].Attribute[pattern]"
) and
output = "ReturnValue.Attribute[re].Attribute[pattern]" and
preservesValue = true
}
}
/** An API node for a `re.Match` object */
private API::Node match() {
result = any(ReMatchSummary c).getACall().(API::CallNode).getReturn()
or
result = re(_).getMember("finditer").getReturn().getASubscript()
}
/**
* A flow summary for methods on a `re.Match` object
*
* See https://docs.python.org/3/library/re.html#re.Match
*/
class ReMatchMethodsSummary extends SummarizedCallable::Range {
string methodName;
ReMatchMethodsSummary() {
this = "re.Match." + methodName and
methodName in ["expand", "group", "groups", "groupdict"]
}
override DataFlow::CallCfgNode getACall() { result = match().getMember(methodName).getACall() }
override DataFlow::ArgumentNode getACallback() { none() }
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
methodName = "expand" and
preservesValue = false and
(
input = "Argument[0]" and output = "ReturnValue"
or
input = "Argument[self].Attribute[string]" and
output = "ReturnValue"
)
or
methodName = "group" and
input = "Argument[self].Attribute[string]" and
output in ["ReturnValue", "ReturnValue.ListElement"] and
preservesValue = false
or
methodName = "groups" and
input = "Argument[self].Attribute[string]" and
output = "ReturnValue.ListElement" and
preservesValue = false
or
methodName = "groupdict" and
input = "Argument[self].Attribute[string]" and
output = "ReturnValue.DictionaryElementAny" and
preservesValue = false
}
}
/**
* A flow summary for `re` methods not returning a `re.Match` object
*
* See https://docs.python.org/3/library/re.html#functions
*/
class ReFunctionsSummary extends SummarizedCallable::Range {
string methodName;
ReFunctionsSummary() {
methodName in ["split", "findall", "finditer", "sub", "subn"] and
this = ["re.", "compiled re."] + methodName
}
override DataFlow::CallCfgNode getACall() {
this = "re." + methodName and
result = API::moduleImport("re").getMember(methodName).getACall()
or
this = "compiled re." + methodName and
result =
any(RePatternSummary c)
.getACall()
.(API::CallNode)
.getReturn()
.getMember(methodName)
.getACall()
}
override DataFlow::ArgumentNode getACallback() { none() }
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
exists(int offset |
// for non-compiled regex the first argument is the pattern, so we need to
// account for this difference
this = "re." + methodName and offset = 0
or
this = "compiled re." + methodName and offset = 1
|
// flow from input string to results
exists(int arg | arg = methodName.(RegexExecutionMethod).getStringArgIndex() - offset |
preservesValue = false and
input in ["Argument[" + arg + "]", "Argument[string:]"] and
(
methodName in ["split", "findall", "finditer"] and
output = "ReturnValue.ListElement"
or
// TODO: Since we currently model iterables as tainted when their elements
// are, the result of findall, finditer, split needs to be tainted
methodName in ["split", "findall", "finditer"] and
output = "ReturnValue"
or
methodName = "sub" and
output = "ReturnValue"
or
methodName = "subn" and
output = "ReturnValue.TupleElement[0]"
)
)
or
// flow from replacement value for substitution
exists(string argumentSpec |
argumentSpec in ["Argument[" + (1 - offset) + "]", "Argument[repl:]"] and
// `repl` can also be a function
input = [argumentSpec, argumentSpec + ".ReturnValue"]
|
(
methodName = "sub" and output = "ReturnValue"
or
methodName = "subn" and output = "ReturnValue.TupleElement[0]"
) and
preservesValue = false
)
or
// flow from input string to attribute on match object
exists(int arg | arg = methodName.(RegexExecutionMethod).getStringArgIndex() - offset |
input in ["Argument[" + arg + "]", "Argument[string:]"] and
methodName = "finditer" and
output = "ReturnValue.ListElement.Attribute[string]" and
preservesValue = true
)
)
}
}
/**
* A call to 're.escape'.
* See https://docs.python.org/3/library/re.html#re.escape
*/
private class ReEscapeCall extends Escaping::Range, DataFlow::CallCfgNode {
ReEscapeCall() { this = API::moduleImport("re").getMember("escape").getACall() }
override DataFlow::Node getAnInput() {
result in [this.getArg(0), this.getArgByName("pattern")]
}
override DataFlow::Node getOutput() { result = this }
override string getKind() { result = Escaping::getRegexKind() }
}
/**
* A node interpreted as a regular expression.
* Speficically nodes where string values are interpreted as regular expressions.
*/
private class StdLibRegExpInterpretation extends RegExpInterpretation::Range {
StdLibRegExpInterpretation() {
this =
API::moduleImport("re").getMember("compile").getACall().getParameter(0, "pattern").asSink()
}
}
// ---------------------------------------------------------------------------
// urllib
// ---------------------------------------------------------------------------
/**
* A call to `urllib.parse.urlsplit`
*
* See https://docs.python.org/3.9/library/urllib.parse.html#urllib.parse.urlsplit
*/
class UrllibParseUrlsplitCall extends Stdlib::SplitResult::InstanceSource, DataFlow::CallCfgNode {
UrllibParseUrlsplitCall() {
this = API::moduleImport("urllib").getMember("parse").getMember("urlsplit").getACall()
}
/** Gets the argument that specifies the URL. */
DataFlow::Node getUrl() { result in [this.getArg(0), this.getArgByName("url")] }
}
/** Extra taint-step such that the result of `urllib.parse.urlsplit(tainted_string)` is tainted. */
private class UrllibParseUrlsplitCallAdditionalTaintStep extends TaintTracking::AdditionalTaintStep
{
override predicate step(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {
nodeTo.(UrllibParseUrlsplitCall).getUrl() = nodeFrom
}
}
// ---------------------------------------------------------------------------
// tempfile
// ---------------------------------------------------------------------------
/**
* A call to `tempfile.mkstemp`.
*
* See https://docs.python.org/3/library/tempfile.html#tempfile.mkstemp
*/
private class TempfileMkstempCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
TempfileMkstempCall() { this = API::moduleImport("tempfile").getMember("mkstemp").getACall() }
override DataFlow::Node getAPathArgument() {
result in [
this.getArg(0), this.getArgByName("suffix"), this.getArg(1), this.getArgByName("prefix"),
this.getArg(2), this.getArgByName("dir")
]
}
}
/**
* A call to `tempfile.NamedTemporaryFile`.
*
* See https://docs.python.org/3/library/tempfile.html#tempfile.NamedTemporaryFile
*/
private class TempfileNamedTemporaryFileCall extends FileSystemAccess::Range,
DataFlow::CallCfgNode
{
TempfileNamedTemporaryFileCall() {
this = API::moduleImport("tempfile").getMember("NamedTemporaryFile").getACall()
}
override DataFlow::Node getAPathArgument() {
result in [
this.getArg(4), this.getArgByName("suffix"), this.getArg(5), this.getArgByName("prefix"),
this.getArg(6), this.getArgByName("dir")
]
}
}
/**
* A call to `tempfile.TemporaryFile`.
*
* See https://docs.python.org/3/library/tempfile.html#tempfile.TemporaryFile
*/
private class TempfileTemporaryFileCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
TempfileTemporaryFileCall() {
this = API::moduleImport("tempfile").getMember("TemporaryFile").getACall()
}
override DataFlow::Node getAPathArgument() {
result in [
this.getArg(4), this.getArgByName("suffix"), this.getArg(5), this.getArgByName("prefix"),
this.getArg(6), this.getArgByName("dir")
]
}
}
/**
* A call to `tempfile.SpooledTemporaryFile`.
*
* See https://docs.python.org/3/library/tempfile.html#tempfile.SpooledTemporaryFile
*/
private class TempfileSpooledTemporaryFileCall extends FileSystemAccess::Range,
DataFlow::CallCfgNode
{
TempfileSpooledTemporaryFileCall() {
this = API::moduleImport("tempfile").getMember("SpooledTemporaryFile").getACall()
}
override DataFlow::Node getAPathArgument() {
result in [
this.getArg(5), this.getArgByName("suffix"), this.getArg(6), this.getArgByName("prefix"),
this.getArg(7), this.getArgByName("dir")
]
}
}
/**
* A call to `tempfile.mkdtemp`.
*
* See https://docs.python.org/3/library/tempfile.html#tempfile.mkdtemp
*/
private class TempfileMkdtempCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
TempfileMkdtempCall() { this = API::moduleImport("tempfile").getMember("mkdtemp").getACall() }
override DataFlow::Node getAPathArgument() {
result in [
this.getArg(0), this.getArgByName("suffix"), this.getArg(1), this.getArgByName("prefix"),
this.getArg(2), this.getArgByName("dir")
]
}
}
/**
* A call to `tempfile.TemporaryDirectory`.
*
* See https://docs.python.org/3/library/tempfile.html#tempfile.TemporaryDirectory
*/
private class TempfileTemporaryDirectoryCall extends FileSystemAccess::Range,
DataFlow::CallCfgNode
{
TempfileTemporaryDirectoryCall() {
this = API::moduleImport("tempfile").getMember("TemporaryDirectory").getACall()
}
override DataFlow::Node getAPathArgument() {
result in [
this.getArg(0), this.getArgByName("suffix"), this.getArg(1), this.getArgByName("prefix"),
this.getArg(2), this.getArgByName("dir")
]
}
}
// ---------------------------------------------------------------------------
// shutil
// ---------------------------------------------------------------------------
/** Gets a reference to the `shutil` module. */
private API::Node shutil() { result = API::moduleImport("shutil") }
/**
* A call to the `shutil.rmtree` function.
*
* See https://docs.python.org/3/library/shutil.html#shutil.rmtree
*/
private class ShutilRmtreeCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
ShutilRmtreeCall() { this = shutil().getMember("rmtree").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* The `shutil` module provides methods to copy, move files or copy file attributes.
* See:
* - https://docs.python.org/3/library/shutil.html#shutil.copyfile
* - https://docs.python.org/3/library/shutil.html#shutil.copymode
* - https://docs.python.org/3/library/shutil.html#shutil.copystat
* - https://docs.python.org/3/library/shutil.html#shutil.copy
* - https://docs.python.org/3/library/shutil.html#shutil.copy2
* - https://docs.python.org/3/library/shutil.html#shutil.copytree
* - https://docs.python.org/3/library/shutil.html#shutil.move
*/
private class ShutilCopyCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
ShutilCopyCall() {
this =
shutil()
.getMember([
// these are used to copy files
"copyfile", "copy", "copy2", "copytree",
// these are used to move files
"move",
// these are used to copy some attributes of the file
"copymode", "copystat"
])
.getACall()
}
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("src"), this.getArg(1), this.getArgByName("dst")]
}
}
// TODO: once we have flow summaries, model `shutil.copyfileobj` which copies the content between its' file-like arguments.
// See https://docs.python.org/3/library/shutil.html#shutil.copyfileobj
private class ShutilCopyfileobjCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
ShutilCopyfileobjCall() { this = shutil().getMember("copyfileobj").getACall() }
override DataFlow::Node getAPathArgument() { none() }
}
/**
* A call to the `shutil.disk_usage` function.
*
* See https://docs.python.org/3/library/shutil.html#shutil.disk_usage
*/
private class ShutilDiskUsageCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
ShutilDiskUsageCall() { this = shutil().getMember("disk_usage").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
/**
* A call to the `shutil.chown` function.
*
* See https://docs.python.org/3/library/shutil.html#shutil.chown
*/
private class ShutilChownCall extends FileSystemAccess::Range, DataFlow::CallCfgNode {
ShutilChownCall() { this = shutil().getMember("chown").getACall() }
override DataFlow::Node getAPathArgument() {
result in [this.getArg(0), this.getArgByName("path")]
}
}
// ---------------------------------------------------------------------------
// io
// ---------------------------------------------------------------------------
/**
* Provides models for the `io.StringIO`/`io.BytesIO` classes
*
* See https://docs.python.org/3.10/library/io.html#io.StringIO.
*/
module StringIO {
/** Gets a reference to the `io.StringIO` class. */
API::Node classRef() {
result = API::moduleImport("io").getMember(["StringIO", "BytesIO"])
or
result = ModelOutput::getATypeNode("io.StringIO~Subclass").getASubclass*()
}
/**
* A source of instances of `io.StringIO`/`io.BytesIO`, extend this class to model new instances.
*
* This can include instantiations of the class, return values from function
* calls, or a special parameter that will be set when functions are called by an external
* library.
*
* Use the predicate `StringIO::instance()` to get references to instances of `io.StringIO`.
*/
abstract class InstanceSource extends Stdlib::FileLikeObject::InstanceSource { }
/** A direct instantiation of `io.StringIO`/`io.BytesIO`. */
private class ClassInstantiation extends InstanceSource, DataFlow::CallCfgNode {
ClassInstantiation() { this = classRef().getACall() }
DataFlow::Node getInitialValue() {
result = this.getArg(0)
or
// `initial_value` for StringIO, `initial_bytes` for BytesIO
result = this.getArgByName(["initial_value", "initial_bytes"])
}
}
/** Gets a reference to an instance of `io.StringIO`/`io.BytesIO`. */
private DataFlow::TypeTrackingNode instance(DataFlow::TypeTracker t) {
t.start() and
result instanceof InstanceSource
or
exists(DataFlow::TypeTracker t2 | result = instance(t2).track(t2, t))
}
/** Gets a reference to an instance of `io.StringIO`/`io.BytesIO`. */
DataFlow::Node instance() { instance(DataFlow::TypeTracker::end()).flowsTo(result) }
/**
* Extra taint propagation for `io.StringIO`/`io.BytesIO`.
*/
private class AdditionalTaintStep extends TaintTracking::AdditionalTaintStep {
override predicate step(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {
nodeTo.(ClassInstantiation).getInitialValue() = nodeFrom
}
}
}
// ---------------------------------------------------------------------------
// xml.etree.ElementTree
// ---------------------------------------------------------------------------
/** Gets a reference to the `xml.etree.ElementTree` class */
API::Node elementTreeClassRef() {
result = API::moduleImport("xml").getMember("etree").getMember("ElementTree").getASubclass*() or
result = ModelOutput::getATypeNode("xml.etree.ElementTree~Subclass").getASubclass*()
}
/**
* An instance of `xml.etree.ElementTree.ElementTree`.
*
* See https://docs.python.org/3.10/library/xml.etree.elementtree.html#xml.etree.ElementTree.ElementTree
*/
private API::Node elementTreeInstance() {
//parse to a tree
result = elementTreeClassRef().getMember("parse").getReturn()
or
// construct a tree without parsing
result = elementTreeClassRef().getMember("ElementTree").getReturn()
}
/**
* An instance of `xml.etree.ElementTree.Element`.
*
* See https://docs.python.org/3.10/library/xml.etree.elementtree.html#xml.etree.ElementTree.Element
*/
private API::Node elementInstance() {
// parse or go to the root of a tree
result = elementTreeInstance().getMember(["parse", "getroot"]).getReturn()
or
// parse directly to an element
result = elementTreeClassRef().getMember(["fromstring", "fromstringlist", "XML"]).getReturn()
or
result = elementTreeClassRef().getMember("XMLParser").getReturn().getMember("close").getReturn()
}
/**
* A call to a find method on a tree or an element will execute an XPath expression.
*/
private class ElementTreeFindCall extends XML::XPathExecution::Range, DataFlow::CallCfgNode {
ElementTreeFindCall() {
exists(string methodName | methodName in ["find", "findall", "findtext"] |
this = elementTreeInstance().getMember(methodName).getACall()
or
this = elementInstance().getMember(methodName).getACall()
)
}
override DataFlow::Node getXPath() { result in [this.getArg(0), this.getArgByName("match")] }
override string getName() { result = "xml.etree" }
}
/**
* Provides models for `xml.etree` parsers
*
* See
* - https://docs.python.org/3.10/library/xml.etree.elementtree.html#xml.etree.ElementTree.XMLParser
* - https://docs.python.org/3.10/library/xml.etree.elementtree.html#xml.etree.ElementTree.XMLPullParser
*/
module XmlParser {
/**
* A source of instances of `xml.etree` parsers, extend this class to model new instances.
*
* This can include instantiations of the class, return values from function
* calls, or a special parameter that will be set when functions are called by an external
* library.
*
* Use the predicate `XmlParser::instance()` to get references to instances of `xml.etree` parsers.
*/
abstract class InstanceSource extends DataFlow::LocalSourceNode { }
/** A direct instantiation of `xml.etree` parsers. */
private class ClassInstantiation extends InstanceSource, DataFlow::CallCfgNode {
ClassInstantiation() {
this = elementTreeClassRef().getMember(["XMLParser", "XMLPullParser"]).getACall()
}
}
/** Gets a reference to an `xml.etree` parser instance. */
private DataFlow::TypeTrackingNode instance(DataFlow::TypeTracker t) {
t.start() and
result instanceof InstanceSource
or
exists(DataFlow::TypeTracker t2 | result = instance(t2).track(t2, t))
}
/** Gets a reference to an `xml.etree` parser instance. */
DataFlow::Node instance() { instance(DataFlow::TypeTracker::end()).flowsTo(result) }
/**
* A call to the `feed` method of an `xml.etree` parser.
*/
private class XmlEtreeParserFeedCall extends DataFlow::MethodCallNode, XML::XmlParsing::Range {
XmlEtreeParserFeedCall() { this.calls(instance(), "feed") }
override DataFlow::Node getAnInput() { result in [this.getArg(0), this.getArgByName("data")] }
override predicate vulnerableTo(XML::XmlParsingVulnerabilityKind kind) { kind.isXmlBomb() }
override predicate mayExecuteInput() { none() }
override DataFlow::Node getOutput() {
exists(DataFlow::Node objRef |
DataFlow::localFlow(this.getObject(), objRef) and
result.(DataFlow::MethodCallNode).calls(objRef, "close")
)
}
}
}
/**
* A call to either of:
* - `xml.etree.ElementTree.fromstring`
* - `xml.etree.ElementTree.fromstringlist`
* - `xml.etree.ElementTree.XML`
* - `xml.etree.ElementTree.XMLID`
* - `xml.etree.ElementTree.parse`
* - `xml.etree.ElementTree.iterparse`
* - `parse` method on an `xml.etree.ElementTree.ElementTree` instance
*
* See
* - https://docs.python.org/3/library/xml.etree.elementtree.html#xml.etree.ElementTree.fromstring
* - https://docs.python.org/3/library/xml.etree.elementtree.html#xml.etree.ElementTree.fromstringlist
* - https://docs.python.org/3/library/xml.etree.elementtree.html#xml.etree.ElementTree.XML
* - https://docs.python.org/3/library/xml.etree.elementtree.html#xml.etree.ElementTree.XMLID
* - https://docs.python.org/3/library/xml.etree.elementtree.html#xml.etree.ElementTree.parse
* - https://docs.python.org/3/library/xml.etree.elementtree.html#xml.etree.ElementTree.iterparse
*/
private class XmlEtreeParsing extends DataFlow::CallCfgNode, XML::XmlParsing::Range {
XmlEtreeParsing() {
this =
elementTreeClassRef()
.getMember(["fromstring", "fromstringlist", "XML", "XMLID", "parse", "iterparse"])
.getACall()
or
this = elementTreeInstance().getMember("parse").getACall()
}
override DataFlow::Node getAnInput() {
result in [
this.getArg(0),
// fromstring / XML / XMLID
this.getArgByName("text"),
// fromstringlist
this.getArgByName("sequence"),
// parse / iterparse
this.getArgByName("source"),
]
}
override predicate vulnerableTo(XML::XmlParsingVulnerabilityKind kind) {
// note: it does not matter what `xml.etree` parser you are using, you cannot
// change the security features anyway :|
kind.isXmlBomb()
}
override predicate mayExecuteInput() { none() }
override DataFlow::Node getOutput() {
// Note: for `XMLID` the result of the call is a tuple with `(root, dict)`, so
// maybe we should not just say that the entire tuple is the decoding output... my
// gut feeling is that THIS instance doesn't matter too much, but that it would be
// nice to be able to do this in general. (this is a problem for both `lxml.etree`
// and `xml.etree`)
result = this
}
}
/**
* A call to `xml.etree.ElementTree.parse` or `xml.etree.ElementTree.iterparse`, which
* takes either a filename or a file-like object as argument. To capture the filename
* for path-injection, we have this subclass.
*
* See
* - https://docs.python.org/3/library/xml.etree.elementtree.html#xml.etree.ElementTree.parse
* - https://docs.python.org/3/library/xml.etree.elementtree.html#xml.etree.ElementTree.iterparse
*/
private class FileAccessFromXmlEtreeParsing extends XmlEtreeParsing, FileSystemAccess::Range {
FileAccessFromXmlEtreeParsing() {
this = elementTreeClassRef().getMember(["parse", "iterparse"]).getACall()
or
this = elementTreeInstance().getMember("parse").getACall()
// I considered whether we should try to reduce FPs from people passing file-like
// objects, which will not be a file system access (and couldn't cause a
// path-injection).
//
// I suppose that once we have proper flow-summary support for file-like objects,
// we can make the XXE/XML-bomb sinks allow an access-path, while the
// path-injection sink wouldn't, and then we will not end up with such FPs.
}
override DataFlow::Node getAPathArgument() { result = this.getAnInput() }
}
// ---------------------------------------------------------------------------
// xml.sax
// ---------------------------------------------------------------------------
/**
* A call to the `setFeature` method on a XML sax parser.
*
* See https://docs.python.org/3.10/library/xml.sax.reader.html#xml.sax.xmlreader.XMLReader.setFeature
*/
private class SaxParserSetFeatureCall extends API::CallNode, DataFlow::MethodCallNode {
SaxParserSetFeatureCall() {
this =
API::moduleImport("xml")
.getMember("sax")
.getMember("make_parser")
.getReturn()
.getMember("setFeature")
.getACall()
}
// The keyword argument names does not match documentation. I checked (with Python
// 3.9.5) that the names used here actually works.
API::Node getFeatureArg() { result = this.getParameter(0, "name") }
API::Node getStateArg() { result = this.getParameter(1, "state") }
}
/**
* Gets a reference to a XML sax parser that has `feature_external_ges` turned on.
*
* See https://docs.python.org/3/library/xml.sax.handler.html#xml.sax.handler.feature_external_ges
*/
private DataFlow::Node saxParserWithFeatureExternalGesTurnedOn(DataFlow::TypeTracker t) {
t.start() and
exists(SaxParserSetFeatureCall call |
call.getFeatureArg().asSink() =
API::moduleImport("xml")
.getMember("sax")
.getMember("handler")
.getMember("feature_external_ges")
.getAValueReachableFromSource() and
call.getStateArg().getAValueReachingSink().asExpr().(BooleanLiteral).booleanValue() = true and
result = call.getObject()
)
or
exists(DataFlow::TypeTracker t2 |
t = t2.smallstep(saxParserWithFeatureExternalGesTurnedOn(t2), result)
) and
// take account of that we can set the feature to False, which makes the parser safe again
not exists(SaxParserSetFeatureCall call |
call.getObject() = result and
call.getFeatureArg().asSink() =
API::moduleImport("xml")
.getMember("sax")
.getMember("handler")
.getMember("feature_external_ges")
.getAValueReachableFromSource() and
call.getStateArg().getAValueReachingSink().asExpr().(BooleanLiteral).booleanValue() = false
)
}
/**
* Gets a reference to a XML sax parser that has `feature_external_ges` turned on.
*
* See https://docs.python.org/3/library/xml.sax.handler.html#xml.sax.handler.feature_external_ges
*/
DataFlow::Node saxParserWithFeatureExternalGesTurnedOn() {
result = saxParserWithFeatureExternalGesTurnedOn(DataFlow::TypeTracker::end())
}
/**
* A call to the `parse` method on a SAX XML parser.
*
* See https://docs.python.org/3/library/xml.sax.reader.html#xml.sax.xmlreader.XMLReader.parse
*/
private class XmlSaxInstanceParsing extends DataFlow::MethodCallNode, XML::XmlParsing::Range,
FileSystemAccess::Range
{
XmlSaxInstanceParsing() {
this =
API::moduleImport("xml")
.getMember("sax")
.getMember("make_parser")
.getReturn()
.getMember("parse")
.getACall()
}
override DataFlow::Node getAnInput() { result in [this.getArg(0), this.getArgByName("source")] }
override predicate vulnerableTo(XML::XmlParsingVulnerabilityKind kind) {
// always vuln to these
kind.isXmlBomb()
or
// can be vuln to other things if features has been turned on
this.getObject() = saxParserWithFeatureExternalGesTurnedOn() and
(kind.isXxe() or kind.isDtdRetrieval())
}
override predicate mayExecuteInput() { none() }
override DataFlow::Node getOutput() {
// note: the output of parsing with SAX is that the content handler gets the
// data... but we don't currently model this (it's not trivial to do, and won't
// really give us any value, at least not as of right now).
none()
}
override DataFlow::Node getAPathArgument() {
// I considered whether we should try to reduce FPs from people passing file-like
// objects, which will not be a file system access (and couldn't cause a
// path-injection).
//
// I suppose that once we have proper flow-summary support for file-like objects,
// we can make the XXE/XML-bomb sinks allow an access-path, while the
// path-injection sink wouldn't, and then we will not end up with such FPs.
result = this.getAnInput()
}
}
/**
* A call to either `parse` or `parseString` from `xml.sax` module.
*
* See:
* - https://docs.python.org/3.10/library/xml.sax.html#xml.sax.parse
* - https://docs.python.org/3.10/library/xml.sax.html#xml.sax.parseString
*/
private class XmlSaxParsing extends DataFlow::CallCfgNode, XML::XmlParsing::Range {
XmlSaxParsing() {
this =
API::moduleImport("xml").getMember("sax").getMember(["parse", "parseString"]).getACall()
}
override DataFlow::Node getAnInput() {
result in [
this.getArg(0),
// parseString
this.getArgByName("string"),
// parse
this.getArgByName("source"),
]
}
override predicate vulnerableTo(XML::XmlParsingVulnerabilityKind kind) {
// always vuln to these
kind.isXmlBomb()
}
override predicate mayExecuteInput() { none() }
override DataFlow::Node getOutput() {
// note: the output of parsing with SAX is that the content handler gets the
// data... but we don't currently model this (it's not trivial to do, and won't
// really give us any value, at least not as of right now).
none()
}
}
/**
* A call to `xml.sax.parse`, which takes either a filename or a file-like object as
* argument. To capture the filename for path-injection, we have this subclass.
*
* See
* - https://docs.python.org/3/library/xml.etree.elementtree.html#xml.etree.ElementTree.parse
* - https://docs.python.org/3/library/xml.etree.elementtree.html#xml.etree.ElementTree.iterparse
*/
private class FileAccessFromXmlSaxParsing extends XmlSaxParsing, FileSystemAccess::Range {
FileAccessFromXmlSaxParsing() {
this = API::moduleImport("xml").getMember("sax").getMember("parse").getACall()
// I considered whether we should try to reduce FPs from people passing file-like
// objects, which will not be a file system access (and couldn't cause a
// path-injection).
//
// I suppose that once we have proper flow-summary support for file-like objects,
// we can make the XXE/XML-bomb sinks allow an access-path, while the
// path-injection sink wouldn't, and then we will not end up with such FPs.
}
override DataFlow::Node getAPathArgument() { result = this.getAnInput() }
}
// ---------------------------------------------------------------------------
// xml.dom.*
// ---------------------------------------------------------------------------
/**
* A call to the `parse` or `parseString` methods from `xml.dom.minidom` or `xml.dom.pulldom`.
*
* Both of these modules are based on SAX parsers.
*
* See
* - https://docs.python.org/3/library/xml.dom.minidom.html#xml.dom.minidom.parse
* - https://docs.python.org/3/library/xml.dom.pulldom.html#xml.dom.pulldom.parse
*/
private class XmlDomParsing extends DataFlow::CallCfgNode, XML::XmlParsing::Range {
XmlDomParsing() {
this =
API::moduleImport("xml")
.getMember("dom")
.getMember(["minidom", "pulldom"])
.getMember(["parse", "parseString"])
.getACall()
}
override DataFlow::Node getAnInput() {
result in [
this.getArg(0),
// parseString
this.getArgByName("string"),
// minidom.parse
this.getArgByName("file"),
// pulldom.parse
this.getArgByName("stream_or_string"),
]
}
DataFlow::Node getParserArg() { result in [this.getArg(1), this.getArgByName("parser")] }
override predicate vulnerableTo(XML::XmlParsingVulnerabilityKind kind) {
this.getParserArg() = saxParserWithFeatureExternalGesTurnedOn() and
(kind.isXxe() or kind.isDtdRetrieval())
or
kind.isXmlBomb()
}
override predicate mayExecuteInput() { none() }
override DataFlow::Node getOutput() { result = this }
}
/**
* A call to the `parse` or `parseString` methods from `xml.dom.minidom` or
* `xml.dom.pulldom`, which takes either a filename or a file-like object as argument.
* To capture the filename for path-injection, we have this subclass.
*
* See
* - https://docs.python.org/3/library/xml.dom.minidom.html#xml.dom.minidom.parse
* - https://docs.python.org/3/library/xml.dom.pulldom.html#xml.dom.pulldom.parse
*/
private class FileAccessFromXmlDomParsing extends XmlDomParsing, FileSystemAccess::Range {
FileAccessFromXmlDomParsing() {
this =
API::moduleImport("xml")
.getMember("dom")
.getMember(["minidom", "pulldom"])
.getMember("parse")
.getACall()
// I considered whether we should try to reduce FPs from people passing file-like
// objects, which will not be a file system access (and couldn't cause a
// path-injection).
//
// I suppose that once we have proper flow-summary support for file-like objects,
// we can make the XXE/XML-bomb sinks allow an access-path, while the
// path-injection sink wouldn't, and then we will not end up with such FPs.
}
override DataFlow::Node getAPathArgument() { result = this.getAnInput() }
}
// ---------------------------------------------------------------------------
// Flow summaries for functions contructing containers
// ---------------------------------------------------------------------------
/**
* A flow summary for `dict`.
*
* see https://docs.python.org/3/library/stdtypes.html#dict
*/
class DictSummary extends SummarizedCallable::Range {
DictSummary() { this = "builtins.dict" }
override DataFlow::CallCfgNode getACall() { result = API::builtin("dict").getACall() }
override DataFlow::ArgumentNode getACallback() {
result = API::builtin("dict").getAValueReachableFromSource()
}
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
// The positional argument contains a mapping.
// TODO: these values can be overwritten by keyword arguments
// - dict mapping
exists(DataFlow::DictionaryElementContent dc, string key | key = dc.getKey() |
input = "Argument[0].DictionaryElement[" + key + "]" and
output = "ReturnValue.DictionaryElement[" + key + "]" and
preservesValue = true
)
or
// - list-of-pairs mapping
input = "Argument[0].ListElement.TupleElement[1]" and
output = "ReturnValue.DictionaryElementAny" and
preservesValue = true
or
// The keyword arguments are added to the dictionary.
exists(DataFlow::DictionaryElementContent dc, string key | key = dc.getKey() |
input = "Argument[" + key + ":]" and
output = "ReturnValue.DictionaryElement[" + key + "]" and
preservesValue = true
)
or
// Imprecise content in the first argument ends up on the container itself.
input = "Argument[0]" and
output = "ReturnValue" and
preservesValue = false
}
}
/** A flow summary for `list`. */
class ListSummary extends SummarizedCallable::Range {
ListSummary() { this = "builtins.list" }
override DataFlow::CallCfgNode getACall() { result = API::builtin("list").getACall() }
override DataFlow::ArgumentNode getACallback() {
result = API::builtin("list").getAValueReachableFromSource()
}
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
(
input = "Argument[0].ListElement"
or
input = "Argument[0].SetElement"
or
exists(DataFlow::TupleElementContent tc, int i | i = tc.getIndex() |
input = "Argument[0].TupleElement[" + i.toString() + "]"
)
// TODO: Once we have DictKeyContent, we need to transform that into ListElementContent
) and
output = "ReturnValue.ListElement" and
preservesValue = true
or
input = "Argument[0]" and
output = "ReturnValue" and
preservesValue = false
}
}
/** A flow summary for tuple */
class TupleSummary extends SummarizedCallable::Range {
TupleSummary() { this = "builtins.tuple" }
override DataFlow::CallCfgNode getACall() { result = API::builtin("tuple").getACall() }
override DataFlow::ArgumentNode getACallback() {
result = API::builtin("tuple").getAValueReachableFromSource()
}
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
exists(DataFlow::TupleElementContent tc, int i | i = tc.getIndex() |
input = "Argument[0].TupleElement[" + i.toString() + "]" and
output = "ReturnValue.TupleElement[" + i.toString() + "]" and
preservesValue = true
)
or
// TODO: We need to also translate iterable content such as list element
// but we currently lack TupleElementAny
input = "Argument[0]" and
output = "ReturnValue" and
preservesValue = false
}
}
/** A flow summary for set */
class SetSummary extends SummarizedCallable::Range {
SetSummary() { this = "builtins.set" }
override DataFlow::CallCfgNode getACall() { result = API::builtin("set").getACall() }
override DataFlow::ArgumentNode getACallback() {
result = API::builtin("set").getAValueReachableFromSource()
}
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
(
input = "Argument[0].ListElement"
or
input = "Argument[0].SetElement"
or
exists(DataFlow::TupleElementContent tc, int i | i = tc.getIndex() |
input = "Argument[0].TupleElement[" + i.toString() + "]"
)
// TODO: Once we have DictKeyContent, we need to transform that into ListElementContent
) and
output = "ReturnValue.SetElement" and
preservesValue = true
or
input = "Argument[0]" and
output = "ReturnValue" and
preservesValue = false
}
}
/** A flow summary for frozenset */
class FrozensetSummary extends SummarizedCallable::Range {
FrozensetSummary() { this = "builtins.frozenset" }
override DataFlow::CallCfgNode getACall() { result = API::builtin("frozenset").getACall() }
override DataFlow::ArgumentNode getACallback() {
result = API::builtin("frozenset").getAValueReachableFromSource()
}
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
any(SetSummary s).propagatesFlow(input, output, preservesValue)
}
}
// ---------------------------------------------------------------------------
// Flow summaries for functions operating on containers
// ---------------------------------------------------------------------------
/** A flow summary for `reversed`. */
class ReversedSummary extends SummarizedCallable::Range {
ReversedSummary() { this = "builtins.reversed" }
override DataFlow::CallCfgNode getACall() { result = API::builtin("reversed").getACall() }
override DataFlow::ArgumentNode getACallback() {
result = API::builtin("reversed").getAValueReachableFromSource()
}
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
(
input = "Argument[0].ListElement"
or
input = "Argument[0].SetElement"
or
exists(DataFlow::TupleElementContent tc, int i | i = tc.getIndex() |
input = "Argument[0].TupleElement[" + i.toString() + "]"
)
// TODO: Once we have DictKeyContent, we need to transform that into ListElementContent
) and
output = "ReturnValue.ListElement" and
preservesValue = true
or
input = "Argument[0]" and
output = "ReturnValue" and
preservesValue = false
}
}
/** A flow summary for `sorted`. */
class SortedSummary extends SummarizedCallable::Range {
SortedSummary() { this = "builtins.sorted" }
override DataFlow::CallCfgNode getACall() { result = API::builtin("sorted").getACall() }
override DataFlow::ArgumentNode getACallback() {
result = API::builtin("sorted").getAValueReachableFromSource()
}
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
exists(string content |
content = "ListElement"
or
content = "SetElement"
or
exists(DataFlow::TupleElementContent tc, int i | i = tc.getIndex() |
content = "TupleElement[" + i.toString() + "]"
)
|
// TODO: Once we have DictKeyContent, we need to transform that into ListElementContent
input = "Argument[0]." + content and
output = "ReturnValue.ListElement" and
preservesValue = true
)
or
input = "Argument[0]" and
output = "ReturnValue" and
preservesValue = false
}
}
/** A flow summary for `iter`. */
class IterSummary extends SummarizedCallable::Range {
IterSummary() { this = "builtins.iter" }
override DataFlow::CallCfgNode getACall() { result = API::builtin("iter").getACall() }
override DataFlow::ArgumentNode getACallback() {
result = API::builtin("iter").getAValueReachableFromSource()
}
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
(
input = "Argument[0].ListElement"
or
input = "Argument[0].SetElement"
or
exists(DataFlow::TupleElementContent tc, int i | i = tc.getIndex() |
input = "Argument[0].TupleElement[" + i.toString() + "]"
)
// TODO: Once we have DictKeyContent, we need to transform that into ListElementContent
) and
output = "ReturnValue.ListElement" and
preservesValue = true
or
input = "Argument[0]" and
output = "ReturnValue" and
preservesValue = false
}
}
/** A flow summary for `next`. */
class NextSummary extends SummarizedCallable::Range {
NextSummary() { this = "builtins.next" }
override DataFlow::CallCfgNode getACall() { result = API::builtin("next").getACall() }
override DataFlow::ArgumentNode getACallback() {
result = API::builtin("next").getAValueReachableFromSource()
}
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
(
input = "Argument[0].ListElement"
or
input = "Argument[0].SetElement"
or
exists(DataFlow::TupleElementContent tc, int i | i = tc.getIndex() |
input = "Argument[0].TupleElement[" + i.toString() + "]"
)
// TODO: Once we have DictKeyContent, we need to transform that into ListElementContent
) and
output = "ReturnValue" and
preservesValue = true
or
input = "Argument[1]" and
output = "ReturnValue" and
preservesValue = true
}
}
/** A flow summary for `map`. */
class MapSummary extends SummarizedCallable::Range {
MapSummary() { this = "builtins.map" }
override DataFlow::CallCfgNode getACall() { result = API::builtin("map").getACall() }
override DataFlow::ArgumentNode getACallback() {
result = API::builtin("map").getAValueReachableFromSource()
}
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
exists(int i | exists(any(Call c).getArg(i)) |
(
input = "Argument[" + (i + 1).toString() + "].ListElement"
or
input = "Argument[" + (i + 1).toString() + "].SetElement"
or
// We reduce generality slightly by not tracking tuple contents on list arguments beyond the first, for performance.
// TODO: Once we have TupleElementAny, this generality can be increased.
i = 0 and
exists(DataFlow::TupleElementContent tc, int j | j = tc.getIndex() |
input = "Argument[1].TupleElement[" + j.toString() + "]"
)
// TODO: Once we have DictKeyContent, we need to transform that into ListElementContent
) and
output = "Argument[0].Parameter[" + i.toString() + "]" and
preservesValue = true
)
or
input = "Argument[0].ReturnValue" and
output = "ReturnValue.ListElement" and
preservesValue = true
}
}
/** A flow summary for `filter`. */
class FilterSummary extends SummarizedCallable::Range {
FilterSummary() { this = "builtins.filter" }
override DataFlow::CallCfgNode getACall() { result = API::builtin("filter").getACall() }
override DataFlow::ArgumentNode getACallback() {
result = API::builtin("filter").getAValueReachableFromSource()
}
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
(
input = "Argument[1].ListElement"
or
input = "Argument[1].SetElement"
or
exists(DataFlow::TupleElementContent tc, int i | i = tc.getIndex() |
input = "Argument[1].TupleElement[" + i.toString() + "]"
)
// TODO: Once we have DictKeyContent, we need to transform that into ListElementContent
) and
(output = "Argument[0].Parameter[0]" or output = "ReturnValue.ListElement") and
preservesValue = true
}
}
/**A summary for `enumerate`. */
class EnumerateSummary extends SummarizedCallable::Range {
EnumerateSummary() { this = "builtins.enumerate" }
override DataFlow::CallCfgNode getACall() { result = API::builtin("enumerate").getACall() }
override DataFlow::ArgumentNode getACallback() {
result = API::builtin("enumerate").getAValueReachableFromSource()
}
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
(
input = "Argument[0].ListElement"
or
input = "Argument[0].SetElement"
or
exists(DataFlow::TupleElementContent tc, int i | i = tc.getIndex() |
input = "Argument[0].TupleElement[" + i.toString() + "]"
)
// TODO: Once we have DictKeyContent, we need to transform that into ListElementContent
) and
output = "ReturnValue.ListElement.TupleElement[1]" and
preservesValue = true
}
}
/** A flow summary for `zip`. */
class ZipSummary extends SummarizedCallable::Range {
ZipSummary() { this = "builtins.zip" }
override DataFlow::CallCfgNode getACall() { result = API::builtin("zip").getACall() }
override DataFlow::ArgumentNode getACallback() {
result = API::builtin("zip").getAValueReachableFromSource()
}
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
exists(int i | exists(any(Call c).getArg(i)) |
(
input = "Argument[" + i.toString() + "].ListElement"
or
input = "Argument[" + i.toString() + "].SetElement"
or
// We reduce generality slightly by not tracking tuple contents on arguments beyond the first two, for performance.
// TODO: Once we have TupleElementAny, this generality can be increased.
i in [0 .. 1] and
exists(DataFlow::TupleElementContent tc, int j | j = tc.getIndex() |
input = "Argument[" + i.toString() + "].TupleElement[" + j.toString() + "]"
)
// TODO: Once we have DictKeyContent, we need to transform that into ListElementContent
) and
output = "ReturnValue.ListElement.TupleElement[" + i.toString() + "]" and
preservesValue = true
)
}
}
// ---------------------------------------------------------------------------
// Flow summaries for container methods
// ---------------------------------------------------------------------------
/** A flow summary for `copy`. */
class CopySummary extends SummarizedCallable::Range {
CopySummary() { this = "collection.copy" }
override DataFlow::CallCfgNode getACall() {
result.(DataFlow::MethodCallNode).getMethodName() = "copy"
}
override DataFlow::ArgumentNode getACallback() { none() }
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
exists(DataFlow::Content c |
input = "Argument[self]." + c.getMaDRepresentation() and
output = "ReturnValue." + c.getMaDRepresentation() and
preservesValue = true
)
or
input = "Argument[self]" and
output = "ReturnValue" and
preservesValue = true
}
}
/** A flow summary for `copy.replace`. */
class ReplaceSummary extends SummarizedCallable::Range {
ReplaceSummary() { this = "copy.replace" }
override DataFlow::CallCfgNode getACall() {
result = API::moduleImport("copy").getMember("replace").getACall()
}
override DataFlow::ArgumentNode getACallback() {
result = API::moduleImport("copy").getMember("replace").getAValueReachableFromSource()
}
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
exists(CallNode c, string name, ControlFlowNode n, DataFlow::AttributeContent ac |
c.getFunction().(NameNode).getId() = "replace" or
c.getFunction().(AttrNode).getName() = "replace"
|
n = c.getArgByName(name) and
ac.getAttribute() = name and
input = "Argument[" + name + ":]" and
output = "ReturnValue." + ac.getMaDRepresentation() and
preservesValue = true
)
}
}
/**
* A flow summary for `pop` either for list or set.
* This ignores the index if given, since content is
* imprecise anyway.
*
* I also handles the default value when `pop` is called
* on a dictionary, since that also does not depend on the key.
*/
class PopSummary extends SummarizedCallable::Range {
PopSummary() { this = "collection.pop" }
override DataFlow::CallCfgNode getACall() {
result.(DataFlow::MethodCallNode).getMethodName() = "pop"
}
override DataFlow::ArgumentNode getACallback() { none() }
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
input = "Argument[self].ListElement" and
output = "ReturnValue" and
preservesValue = true
or
input = "Argument[self].SetElement" and
output = "ReturnValue" and
preservesValue = true
or
// default value for dictionary
input = "Argument[1]" and
output = "ReturnValue" and
preservesValue = true
or
// transfer taint on self to return value
input = "Argument[self]" and
output = "ReturnValue" and
preservesValue = false
}
}
/** A flow summary for `dict.pop` */
class DictPopSummary extends SummarizedCallable::Range {
string key;
DictPopSummary() {
this = "dict.pop(" + key + ")" and
exists(DataFlow::DictionaryElementContent dc | key = dc.getKey())
}
override DataFlow::CallCfgNode getACall() {
result.(DataFlow::MethodCallNode).getMethodName() = "pop" and
result.getArg(0).getALocalSource().asExpr().(StringLiteral).getText() = key
}
override DataFlow::ArgumentNode getACallback() { none() }
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
input = "Argument[self].DictionaryElement[" + key + "]" and
output = "ReturnValue" and
preservesValue = true
}
}
/** A flow summary for `dict.get` at specific content. */
class DictGetSummary extends SummarizedCallable::Range {
string key;
DictGetSummary() {
this = "dict.get(" + key + ")" and
exists(DataFlow::DictionaryElementContent dc | key = dc.getKey())
}
override DataFlow::CallCfgNode getACall() {
result.(DataFlow::MethodCallNode).getMethodName() = "get" and
result.getArg(0).getALocalSource().asExpr().(StringLiteral).getText() = key
}
override DataFlow::ArgumentNode getACallback() { none() }
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
input = "Argument[self].DictionaryElement[" + key + "]" and
output = "ReturnValue" and
preservesValue = true
or
// optional default value
input = "Argument[1]" and
output = "ReturnValue" and
preservesValue = true
}
}
/** A flow summary for `dict.get` disregarding content. */
class DictGetAnySummary extends SummarizedCallable::Range {
DictGetAnySummary() { this = "dict.get" }
override DataFlow::CallCfgNode getACall() {
result.(DataFlow::MethodCallNode).getMethodName() = "get"
}
override DataFlow::ArgumentNode getACallback() { none() }
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
// default value
input = "Argument[1]" and
output = "ReturnValue" and
preservesValue = true
or
// transfer taint from self to return value
input = "Argument[self]" and
output = "ReturnValue" and
preservesValue = false
}
}
/** A flow summary for `dict.popitem` */
class DictPopitemSummary extends SummarizedCallable::Range {
DictPopitemSummary() { this = "dict.popitem" }
override DataFlow::CallCfgNode getACall() {
result.(DataFlow::MethodCallNode).getMethodName() = "popitem"
}
override DataFlow::ArgumentNode getACallback() { none() }
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
exists(DataFlow::DictionaryElementContent dc, string key | key = dc.getKey() |
input = "Argument[self].DictionaryElement[" + key + "]" and
output = "ReturnValue.TupleElement[1]" and
preservesValue = true
// TODO: put `key` into "ReturnValue.TupleElement[0]"
)
}
}
/**
* A flow summary for `dict.setdefault`.
*
* See https://docs.python.org/3.10/library/stdtypes.html#dict.setdefault
*/
class DictSetdefaultSummary extends SummarizedCallable::Range {
DictSetdefaultSummary() { this = "dict.setdefault" }
override DataFlow::CallCfgNode getACall() {
result.(DataFlow::MethodCallNode).calls(_, "setdefault")
}
override DataFlow::ArgumentNode getACallback() {
result.(DataFlow::AttrRead).getAttributeName() = "setdefault"
}
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
// store/read steps with dictionary content of this is modeled in DataFlowPrivate
input = "Argument[1]" and
output = "ReturnValue" and
preservesValue = true
}
}
/**
* A flow summary for `dict.setdefault` at specific content.
* See https://docs.python.org/3.10/library/stdtypes.html#dict.setdefault
* This summary handles read and store steps. See `DictSetdefaultSummary`
* for the dataflow steps.
*/
class DictSetdefaultKeySummary extends SummarizedCallable::Range {
string key;
DictSetdefaultKeySummary() {
this = "dict.setdefault(" + key + ")" and
exists(DataFlow::DictionaryElementContent dc | key = dc.getKey())
}
override DataFlow::CallCfgNode getACall() {
result.(DataFlow::MethodCallNode).getMethodName() = "setdefault" and
result.getArg(0).getALocalSource().asExpr().(StringLiteral).getText() = key
}
override DataFlow::ArgumentNode getACallback() { none() }
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
// If key is in the dictionary, return its value.
input = "Argument[self].DictionaryElement[" + key + "]" and
output = "ReturnValue" and
preservesValue = true
or
// If not, insert key with a value of default.
input = "Argument[1]" and
output = "ReturnValue.DictionaryElement[" + key + "]" and
preservesValue = true
}
}
/**
* A flow summary for `dict.values`.
*
* See https://docs.python.org/3.10/library/stdtypes.html#dict.values
*/
class DictValues extends SummarizedCallable::Range {
DictValues() { this = "dict.values" }
override DataFlow::CallCfgNode getACall() {
result.(DataFlow::MethodCallNode).calls(_, "values")
}
override DataFlow::ArgumentNode getACallback() {
result.(DataFlow::AttrRead).getAttributeName() = "values"
}
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
exists(DataFlow::DictionaryElementContent dc, string key | key = dc.getKey() |
input = "Argument[self].DictionaryElement[" + key + "]" and
output = "ReturnValue.ListElement" and
preservesValue = true
)
or
input = "Argument[self]" and
output = "ReturnValue" and
preservesValue = false
}
}
/**
* A flow summary for `dict.keys`.
*
* See https://docs.python.org/3.10/library/stdtypes.html#dict.keys
*/
class DictKeys extends SummarizedCallable::Range {
DictKeys() { this = "dict.keys" }
override DataFlow::CallCfgNode getACall() { result.(DataFlow::MethodCallNode).calls(_, "keys") }
override DataFlow::ArgumentNode getACallback() {
result.(DataFlow::AttrRead).getAttributeName() = "keys"
}
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
// TODO: Once we have DictKeyContent, we need to transform that into ListElementContent
input = "Argument[self]" and
output = "ReturnValue" and
preservesValue = false
}
}
/**
* A flow summary for `dict.items`.
*
* See https://docs.python.org/3.10/library/stdtypes.html#dict.items
*/
class DictItems extends SummarizedCallable::Range {
DictItems() { this = "dict.items" }
override DataFlow::CallCfgNode getACall() {
result.(DataFlow::MethodCallNode).calls(_, "items")
}
override DataFlow::ArgumentNode getACallback() {
result.(DataFlow::AttrRead).getAttributeName() = "items"
}
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
exists(DataFlow::DictionaryElementContent dc, string key | key = dc.getKey() |
input = "Argument[self].DictionaryElement[" + key + "]" and
output = "ReturnValue.ListElement.TupleElement[1]" and
preservesValue = true
)
or
// TODO: Add the keys to output list
input = "Argument[self]" and
output = "ReturnValue" and
preservesValue = false
}
}
/**
* A flow summary for `list.append`.
*
* See https://docs.python.org/3.10/library/stdtypes.html#typesseq-mutable
*/
class ListAppend extends SummarizedCallable::Range {
ListAppend() { this = "list.append" }
override DataFlow::CallCfgNode getACall() {
result.(DataFlow::MethodCallNode).calls(_, "append")
}
override DataFlow::ArgumentNode getACallback() {
result.(DataFlow::AttrRead).getAttributeName() = "append"
}
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
// newly added element added to this
input = "Argument[0]" and
output = "Argument[self].ListElement" and
preservesValue = true
or
// transfer taint from new element to this (TODO: remove in future when taint-handling is more in line with other languages)
input = "Argument[0]" and
output = "Argument[self]" and
preservesValue = false
}
}
/**
* A flow summary for `set.add`.
*
* See https://docs.python.org/3.10/library/stdtypes.html#frozenset.add
*/
class SetAdd extends SummarizedCallable::Range {
SetAdd() { this = "set.add" }
override DataFlow::CallCfgNode getACall() { result.(DataFlow::MethodCallNode).calls(_, "add") }
override DataFlow::ArgumentNode getACallback() {
result.(DataFlow::AttrRead).getAttributeName() = "add"
}
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
// newly added element added to this
input = "Argument[0]" and
output = "Argument[self].SetElement" and
preservesValue = true
or
// transfer taint from new element to this (TODO: remove in future when taint-handling is more in line with other languages)
input = "Argument[0]" and
output = "Argument[self]" and
preservesValue = false
}
}
/**
* A flow summary for `os.getenv` / `os.getenvb`
*
* See https://devdocs.io/python~3.11/library/os#os.getenv
*/
class OsGetEnv extends SummarizedCallable::Range {
OsGetEnv() { this = "os.getenv" }
override DataFlow::CallCfgNode getACall() {
result = API::moduleImport("os").getMember(["getenv", "getenvb"]).getACall()
}
override DataFlow::ArgumentNode getACallback() {
result =
API::moduleImport("os").getMember(["getenv", "getenvb"]).getAValueReachableFromSource()
}
override predicate propagatesFlow(string input, string output, boolean preservesValue) {
input in ["Argument[1]", "Argument[default:]"] and
output = "ReturnValue" and
preservesValue = true
}
}
// ---------------------------------------------------------------------------
// asyncio
// ---------------------------------------------------------------------------
/** Provides models for the `asyncio` module. */
module AsyncIO {
/**
* A call to the `asyncio.create_subprocess_exec` function (also accessible via the `subprocess` module of `asyncio`)
*
* See https://docs.python.org/3/library/asyncio-subprocess.html#creating-subprocesses
*/
private class CreateSubprocessExec extends SystemCommandExecution::Range,
FileSystemAccess::Range, API::CallNode
{
CreateSubprocessExec() {
this = API::moduleImport("asyncio").getMember("create_subprocess_exec").getACall()
or
this =
API::moduleImport("asyncio")
.getMember("subprocess")
.getMember("create_subprocess_exec")
.getACall()
}
override DataFlow::Node getCommand() { result = this.getParameter(0, "program").asSink() }
override DataFlow::Node getAPathArgument() { result = this.getCommand() }
override predicate isShellInterpreted(DataFlow::Node arg) {
none() // this is a safe API.
}
}
/**
* A call to the `asyncio.create_subprocess_shell` function (also accessible via the `subprocess` module of `asyncio`)
*
* See https://docs.python.org/3/library/asyncio-subprocess.html#asyncio.create_subprocess_shell
*/
private class CreateSubprocessShell extends SystemCommandExecution::Range,
FileSystemAccess::Range, API::CallNode
{
CreateSubprocessShell() {
this = API::moduleImport("asyncio").getMember("create_subprocess_shell").getACall()
or
this =
API::moduleImport("asyncio")
.getMember("subprocess")
.getMember("create_subprocess_shell")
.getACall()
}
override DataFlow::Node getCommand() { result = this.getParameter(0, "cmd").asSink() }
override DataFlow::Node getAPathArgument() { result = this.getCommand() }
override predicate isShellInterpreted(DataFlow::Node arg) { arg = this.getCommand() }
}
/**
* Get an asyncio event loop (an object with basetype `AbstractEventLoop`).
*
* See https://docs.python.org/3/library/asyncio-eventloop.html
*/
private API::Node getAsyncioEventLoop() {
result = API::moduleImport("asyncio").getMember("get_running_loop").getReturn()
or
result = API::moduleImport("asyncio").getMember("get_event_loop").getReturn() // deprecated in Python 3.10.0 and later
or
result = API::moduleImport("asyncio").getMember("new_event_loop").getReturn()
}
/**
* A call to `subprocess_exec` on an event loop instance.
*
* See https://docs.python.org/3/library/asyncio-eventloop.html#asyncio.loop.subprocess_exec
*/
private class EventLoopSubprocessExec extends API::CallNode, SystemCommandExecution::Range,
FileSystemAccess::Range
{
EventLoopSubprocessExec() {
this = getAsyncioEventLoop().getMember("subprocess_exec").getACall()
}
override DataFlow::Node getCommand() { result = this.getArg(1) }
override DataFlow::Node getAPathArgument() { result = this.getCommand() }
override predicate isShellInterpreted(DataFlow::Node arg) {
none() // this is a safe API.
}
}
/**
* A call to `subprocess_shell` on an event loop instance.
*
* See https://docs.python.org/3/library/asyncio-eventloop.html#asyncio.loop.subprocess_shell
*/
private class EventLoopSubprocessShell extends API::CallNode, SystemCommandExecution::Range,
FileSystemAccess::Range
{
EventLoopSubprocessShell() {
this = getAsyncioEventLoop().getMember("subprocess_shell").getACall()
}
override DataFlow::Node getCommand() { result = this.getParameter(1, "cmd").asSink() }
override DataFlow::Node getAPathArgument() { result = this.getCommand() }
override predicate isShellInterpreted(DataFlow::Node arg) { arg = this.getCommand() }
}
}
// ---------------------------------------------------------------------------
// html
// ---------------------------------------------------------------------------
/**
* A call to 'html.escape'.
* See https://docs.python.org/3/library/html.html#html.escape
*/
private class HtmlEscapeCall extends Escaping::Range, API::CallNode {
HtmlEscapeCall() {
this = API::moduleImport("html").getMember("escape").getACall() and
// if quote escaping is disabled, that might lead to XSS if the result is inserted
// in the attribute value of a tag, such as `<foo bar="escape_result">`. Since we
// don't know how values are being inserted, and we don't want to lose these
// results (FNs), we require quote escaping to be enabled. This might lead to some
// FPs, so we might need to revisit this in the future.
not this.getParameter(1, "quote")
.getAValueReachingSink()
.asExpr()
.(ImmutableLiteral)
.booleanValue() = false
}
override DataFlow::Node getAnInput() { result = this.getParameter(0, "s").asSink() }
override DataFlow::Node getOutput() { result = this }
override string getKind() { result = Escaping::getHtmlKind() }
}
// ---------------------------------------------------------------------------
// argparse
// ---------------------------------------------------------------------------
/**
* if result of `parse_args` is tainted (because it uses command-line arguments),
* then the parsed values accesssed on any attribute lookup is also tainted.
*/
private class ArgumentParserAnyAttributeStep extends TaintTracking::AdditionalTaintStep {
override predicate step(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {
nodeFrom =
API::moduleImport("argparse")
.getMember("ArgumentParser")
.getReturn()
.getMember("parse_args")
.getReturn()
.getAValueReachableFromSource() and
nodeTo.(DataFlow::AttrRead).getObject() = nodeFrom
}
}
// ---------------------------------------------------------------------------
// sys
// ---------------------------------------------------------------------------
/**
* An access of `sys.stdin`/`sys.stdout`/`sys.stderr`, to get additional FileLike
* modeling.
*/
private class SysStandardStreams extends Stdlib::FileLikeObject::InstanceSource, DataFlow::Node {
SysStandardStreams() {
this = API::moduleImport("sys").getMember(["stdin", "stdout", "stderr"]).asSource()
}
}
}
// ---------------------------------------------------------------------------
// OTHER
// ---------------------------------------------------------------------------
/**
* A call to the `startswith` method on a string.
* See https://docs.python.org/3.9/library/stdtypes.html#str.startswith
*/
private class StartswithCall extends Path::SafeAccessCheck::Range {
StartswithCall() { this.(CallNode).getFunction().(AttrNode).getName() = "startswith" }
override predicate checks(ControlFlowNode node, boolean branch) {
node = this.(CallNode).getFunction().(AttrNode).getObject() and
branch = true
}
}
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