Files
codeql/cpp/ql/lib/semmle/code/cpp/dataflow/ExternalFlow.qll
Mathias Vorreiter Pedersen 5deb9002bf Merge pull request #16665 from geoffw0/yml
C++: Support for extension models (.yml)
2024-06-06 14:21:42 +01:00

568 lines
21 KiB
Plaintext

/**
* INTERNAL use only. This is an experimental API subject to change without notice.
*
* Provides classes and predicates for dealing with flow models specified in CSV format.
*
* The CSV specification has the following columns:
* - Sources:
* `namespace; type; subtypes; name; signature; ext; output; kind`
* - Sinks:
* `namespace; type; subtypes; name; signature; ext; input; kind`
* - Summaries:
* `namespace; type; subtypes; name; signature; ext; input; output; kind`
*
* The interpretation of a row is similar to API-graphs with a left-to-right
* reading.
* 1. The `namespace` column selects a namespace.
* 2. The `type` column selects a type within that namespace.
* 3. The `subtypes` is a boolean that indicates whether to jump to an
* arbitrary subtype of that type. Set this to `false` if leaving the `type`
* blank (for example, a free function).
* 4. The `name` column optionally selects a specific named member of the type.
* 5. The `signature` column optionally restricts the named member. If
* `signature` is blank then no such filtering is done. The format of the
* signature is a comma-separated list of types enclosed in parentheses. The
* types can be short names or fully qualified names (mixing these two options
* is not allowed within a single signature).
* 6. The `ext` column specifies additional API-graph-like edges. Currently
* there is only one valid value: "".
* 7. The `input` column specifies how data enters the element selected by the
* first 6 columns, and the `output` column specifies how data leaves the
* element selected by the first 6 columns. An `input` can be either:
* - "": Selects a write to the selected element in case this is a field.
* - "Argument[n]": Selects an argument in a call to the selected element.
* The arguments are zero-indexed, and `-1` specifies the qualifier object,
* that is, `*this`.
* - one or more "*" can be added in front of the argument index to indicate
* indirection, for example, `Argument[*0]` indicates the first indirection
* of the 0th argument.
* - `n1..n2` syntax can be used to indicate a range of arguments, inclusive
* at both ends. One or more "*"s can be added in front of the whole range
* to indicate that every argument in the range is indirect, for example
* `*0..1` is the first indirection of both arguments 0 and 1.
* - "ReturnValue": Selects a value being returned by the selected element.
* One or more "*" can be added as an argument to indicate indirection, for
* example, "ReturnValue[*]" indicates the first indirection of the return
* value.
*
* An `output` can be either:
* - "": Selects a read of a selected field.
* - "Argument[n]": Selects the post-update value of an argument in a call to
* the selected element. That is, the value of the argument after the call
* returns. The arguments are zero-indexed, and `-1` specifies the qualifier
* object, that is, `*this`.
* - one or more "*" can be added in front of the argument index to indicate
* indirection, for example, `Argument[*0]` indicates the first indirection
* of the 0th argument.
* - `n1..n2` syntax can be used to indicate a range of arguments, inclusive
* at both ends. One or more "*"s can be added in front of the whole range
* to indicate that every argument in the range is indirect, for example
* `*0..1` is the first indirection of both arguments 0 and 1.
* - "Parameter[n]": Selects the value of a parameter of the selected element.
* The syntax is the same as for "Argument", for example "Parameter[0]",
* "Parameter[*0]", "Parameter[0..2]" etc.
* - "ReturnValue": Selects a value being returned by the selected element.
* One or more "*" can be added as an argument to indicate indirection, for
* example, "ReturnValue[*]" indicates the first indirection of the return
* value.
* 8. The `kind` column is a tag that can be referenced from QL to determine to
* which classes the interpreted elements should be added. For example, for
* sources "remote" indicates a default remote flow source, and for summaries
* "taint" indicates a default additional taint step and "value" indicates a
* globally applicable value-preserving step.
*/
import cpp
private import new.DataFlow
private import internal.FlowSummaryImpl
private import internal.FlowSummaryImpl::Public
private import internal.FlowSummaryImpl::Private
private import internal.FlowSummaryImpl::Private::External
private import internal.ExternalFlowExtensions as Extensions
private import codeql.mad.ModelValidation as SharedModelVal
private import codeql.util.Unit
/**
* A unit class for adding additional source model rows.
*
* Extend this class to add additional source definitions.
*/
class SourceModelCsv extends Unit {
/** Holds if `row` specifies a source definition. */
abstract predicate row(string row);
}
/**
* A unit class for adding additional sink model rows.
*
* Extend this class to add additional sink definitions.
*/
class SinkModelCsv extends Unit {
/** Holds if `row` specifies a sink definition. */
abstract predicate row(string row);
}
/**
* A unit class for adding additional summary model rows.
*
* Extend this class to add additional flow summary definitions.
*/
class SummaryModelCsv extends Unit {
/** Holds if `row` specifies a summary definition. */
abstract predicate row(string row);
}
/** Holds if `row` is a source model. */
predicate sourceModel(string row) { any(SourceModelCsv s).row(row) }
/** Holds if `row` is a sink model. */
predicate sinkModel(string row) { any(SinkModelCsv s).row(row) }
/** Holds if `row` is a summary model. */
predicate summaryModel(string row) { any(SummaryModelCsv s).row(row) }
/** Holds if a source model exists for the given parameters. */
predicate sourceModel(
string namespace, string type, boolean subtypes, string name, string signature, string ext,
string output, string kind, string provenance
) {
exists(string row |
sourceModel(row) and
row.splitAt(";", 0) = namespace and
row.splitAt(";", 1) = type and
row.splitAt(";", 2) = subtypes.toString() and
subtypes = [true, false] and
row.splitAt(";", 3) = name and
row.splitAt(";", 4) = signature and
row.splitAt(";", 5) = ext and
row.splitAt(";", 6) = output and
row.splitAt(";", 7) = kind
) and
provenance = "manual"
or
Extensions::sourceModel(namespace, type, subtypes, name, signature, ext, output, kind, provenance,
_)
}
/** Holds if a sink model exists for the given parameters. */
predicate sinkModel(
string namespace, string type, boolean subtypes, string name, string signature, string ext,
string input, string kind, string provenance
) {
exists(string row |
sinkModel(row) and
row.splitAt(";", 0) = namespace and
row.splitAt(";", 1) = type and
row.splitAt(";", 2) = subtypes.toString() and
subtypes = [true, false] and
row.splitAt(";", 3) = name and
row.splitAt(";", 4) = signature and
row.splitAt(";", 5) = ext and
row.splitAt(";", 6) = input and
row.splitAt(";", 7) = kind
) and
provenance = "manual"
or
Extensions::sinkModel(namespace, type, subtypes, name, signature, ext, input, kind, provenance, _)
}
/** Holds if a summary model exists for the given parameters. */
predicate summaryModel(
string namespace, string type, boolean subtypes, string name, string signature, string ext,
string input, string output, string kind, string provenance
) {
exists(string row |
summaryModel(row) and
row.splitAt(";", 0) = namespace and
row.splitAt(";", 1) = type and
row.splitAt(";", 2) = subtypes.toString() and
subtypes = [true, false] and
row.splitAt(";", 3) = name and
row.splitAt(";", 4) = signature and
row.splitAt(";", 5) = ext and
row.splitAt(";", 6) = input and
row.splitAt(";", 7) = output and
row.splitAt(";", 8) = kind
) and
provenance = "manual"
or
Extensions::summaryModel(namespace, type, subtypes, name, signature, ext, input, output, kind,
provenance, _)
}
private predicate relevantNamespace(string namespace) {
sourceModel(namespace, _, _, _, _, _, _, _, _) or
sinkModel(namespace, _, _, _, _, _, _, _, _) or
summaryModel(namespace, _, _, _, _, _, _, _, _, _)
}
private predicate namespaceLink(string shortns, string longns) {
relevantNamespace(shortns) and
relevantNamespace(longns) and
longns.prefix(longns.indexOf("::")) = shortns
}
private predicate canonicalNamespace(string namespace) {
relevantNamespace(namespace) and not namespaceLink(_, namespace)
}
private predicate canonicalNamespaceLink(string namespace, string subns) {
canonicalNamespace(namespace) and
(subns = namespace or namespaceLink(namespace, subns))
}
/**
* Holds if MaD framework coverage of `namespace` is `n` api endpoints of the
* kind `(kind, part)`, and `namespaces` is the number of subnamespaces of
* `namespace` which have MaD framework coverage (including `namespace`
* itself).
*/
predicate modelCoverage(string namespace, int namespaces, string kind, string part, int n) {
namespaces = strictcount(string subns | canonicalNamespaceLink(namespace, subns)) and
(
part = "source" and
n =
strictcount(string subns, string type, boolean subtypes, string name, string signature,
string ext, string output, string provenance |
canonicalNamespaceLink(namespace, subns) and
sourceModel(subns, type, subtypes, name, signature, ext, output, kind, provenance)
)
or
part = "sink" and
n =
strictcount(string subns, string type, boolean subtypes, string name, string signature,
string ext, string input, string provenance |
canonicalNamespaceLink(namespace, subns) and
sinkModel(subns, type, subtypes, name, signature, ext, input, kind, provenance)
)
or
part = "summary" and
n =
strictcount(string subns, string type, boolean subtypes, string name, string signature,
string ext, string input, string output, string provenance |
canonicalNamespaceLink(namespace, subns) and
summaryModel(subns, type, subtypes, name, signature, ext, input, output, kind, provenance)
)
)
}
/** Provides a query predicate to check the CSV data for validation errors. */
module CsvValidation {
private string getInvalidModelInput() {
exists(string pred, AccessPath input, string part |
sinkModel(_, _, _, _, _, _, input, _, _) and pred = "sink"
or
summaryModel(_, _, _, _, _, _, input, _, _, _) and pred = "summary"
|
(
invalidSpecComponent(input, part) and
not part = "" and
not (part = "Argument" and pred = "sink") and
not parseArg(part, _)
or
part = input.getToken(_) and
parseParam(part, _)
) and
result = "Unrecognized input specification \"" + part + "\" in " + pred + " model."
)
}
private string getInvalidModelOutput() {
exists(string pred, string output, string part |
sourceModel(_, _, _, _, _, _, output, _, _) and pred = "source"
or
summaryModel(_, _, _, _, _, _, _, output, _, _) and pred = "summary"
|
invalidSpecComponent(output, part) and
not part = "" and
not (part = ["Argument", "Parameter"] and pred = "source") and
result = "Unrecognized output specification \"" + part + "\" in " + pred + " model."
)
}
private module KindValConfig implements SharedModelVal::KindValidationConfigSig {
predicate summaryKind(string kind) { summaryModel(_, _, _, _, _, _, _, _, kind, _) }
predicate sinkKind(string kind) { sinkModel(_, _, _, _, _, _, _, kind, _) }
predicate sourceKind(string kind) { sourceModel(_, _, _, _, _, _, _, kind, _) }
}
private module KindVal = SharedModelVal::KindValidation<KindValConfig>;
private string getInvalidModelSubtype() {
exists(string pred, string row |
sourceModel(row) and pred = "source"
or
sinkModel(row) and pred = "sink"
or
summaryModel(row) and pred = "summary"
|
exists(string b |
b = row.splitAt(";", 2) and
not b = ["true", "false"] and
result = "Invalid boolean \"" + b + "\" in " + pred + " model."
)
)
}
private string getInvalidModelColumnCount() {
exists(string pred, string row, int expect |
sourceModel(row) and expect = 8 and pred = "source"
or
sinkModel(row) and expect = 8 and pred = "sink"
or
summaryModel(row) and expect = 9 and pred = "summary"
|
exists(int cols |
cols = 1 + max(int n | exists(row.splitAt(";", n))) and
cols != expect and
result =
"Wrong number of columns in " + pred + " model row, expected " + expect + ", got " + cols +
"."
)
)
}
private string getInvalidModelSignature() {
exists(string pred, string namespace, string type, string name, string signature, string ext |
sourceModel(namespace, type, _, name, signature, ext, _, _, _) and pred = "source"
or
sinkModel(namespace, type, _, name, signature, ext, _, _, _) and pred = "sink"
or
summaryModel(namespace, type, _, name, signature, ext, _, _, _, _) and pred = "summary"
|
not namespace.regexpMatch("[a-zA-Z0-9_\\.:]*") and
result = "Dubious namespace \"" + namespace + "\" in " + pred + " model."
or
not type.regexpMatch("[a-zA-Z0-9_<>,\\+]*") and
result = "Dubious type \"" + type + "\" in " + pred + " model."
or
not name.regexpMatch("[a-zA-Z0-9_<>,]*") and
result = "Dubious member name \"" + name + "\" in " + pred + " model."
or
not signature.regexpMatch("|\\([a-zA-Z0-9_<>\\.\\+\\*,\\[\\]]*\\)") and
result = "Dubious signature \"" + signature + "\" in " + pred + " model."
or
not ext.regexpMatch("|Attribute") and
result = "Unrecognized extra API graph element \"" + ext + "\" in " + pred + " model."
)
}
/** Holds if some row in a CSV-based flow model appears to contain typos. */
query predicate invalidModelRow(string msg) {
msg =
[
getInvalidModelSignature(), getInvalidModelInput(), getInvalidModelOutput(),
getInvalidModelSubtype(), getInvalidModelColumnCount(), KindVal::getInvalidModelKind()
]
}
}
private predicate elementSpec(
string namespace, string type, boolean subtypes, string name, string signature, string ext
) {
sourceModel(namespace, type, subtypes, name, signature, ext, _, _, _) or
sinkModel(namespace, type, subtypes, name, signature, ext, _, _, _) or
summaryModel(namespace, type, subtypes, name, signature, ext, _, _, _, _)
}
private string paramsStringPart(Function c, int i) {
i = -1 and result = "(" and exists(c)
or
exists(int n, string p | c.getParameter(n).getType().toString() = p |
i = 2 * n and result = p
or
i = 2 * n - 1 and result = "," and n != 0
)
or
i = 2 * c.getNumberOfParameters() and result = ")"
}
/**
* Gets a parenthesized string containing all parameter types of this callable, separated by a comma.
*
* Returns the empty string if the callable has no parameters.
* Parameter types are represented by their type erasure.
*/
cached
private string paramsString(Function c) {
result = concat(int i | | paramsStringPart(c, i) order by i)
}
bindingset[func]
private predicate matchesSignature(Function func, string signature) {
signature = "" or
paramsString(func) = signature
}
/**
* Gets the element in module `namespace` that satisfies the following properties:
* 1. If the element is a member of a class-like type, then the class-like type has name `type`
* 2. If `subtypes = true` and the element is a member of a class-like type, then overrides of the element
* are also returned.
* 3. The element has name `name`
* 4. If `signature` is non-empty, then the element has a list of parameter types described by `signature`.
*
* NOTE: `namespace` is currently not used (since we don't properly extract modules yet).
*/
pragma[nomagic]
private Element interpretElement0(
string namespace, string type, boolean subtypes, string name, string signature
) {
elementSpec(namespace, type, subtypes, name, signature, _) and
(
// Non-member functions
exists(Function func |
func.hasQualifiedName(namespace, name) and
type = "" and
matchesSignature(func, signature) and
subtypes = false and
not exists(func.getDeclaringType()) and
result = func
)
or
// Member functions
exists(Class namedClass, Class classWithMethod, Function method |
classWithMethod = method.getClassAndName(name) and
namedClass.hasQualifiedName(namespace, type) and
matchesSignature(method, signature) and
result = method
|
// member declared in the named type or a subtype of it
subtypes = true and
classWithMethod = namedClass.getADerivedClass*()
or
// member declared directly in the named type
subtypes = false and
classWithMethod = namedClass
)
or
// Member variables
signature = "" and
exists(Class namedClass, Class classWithMember, MemberVariable member |
member.getName() = name and
member = classWithMember.getAMember() and
namedClass.hasQualifiedName(namespace, type) and
result = member
|
// field declared in the named type or a subtype of it (or an extension of any)
subtypes = true and
classWithMember = namedClass.getADerivedClass*()
or
// field declared directly in the named type (or an extension of it)
subtypes = false and
classWithMember = namedClass
)
or
// Global or namespace variables
signature = "" and
type = "" and
subtypes = false and
result = any(GlobalOrNamespaceVariable v | v.hasQualifiedName(namespace, name))
)
}
/** Gets the source/sink/summary element corresponding to the supplied parameters. */
Element interpretElement(
string namespace, string type, boolean subtypes, string name, string signature, string ext
) {
elementSpec(namespace, type, subtypes, name, signature, ext) and
exists(Element e | e = interpretElement0(namespace, type, subtypes, name, signature) |
ext = "" and result = e
)
}
cached
private module Cached {
/**
* Holds if `node` is specified as a source with the given kind in a CSV flow
* model.
*/
cached
predicate sourceNode(DataFlow::Node node, string kind) {
exists(SourceSinkInterpretationInput::InterpretNode n |
isSourceNode(n, kind, _) and n.asNode() = node // TODO
)
}
/**
* Holds if `node` is specified as a sink with the given kind in a CSV flow
* model.
*/
cached
predicate sinkNode(DataFlow::Node node, string kind) {
exists(SourceSinkInterpretationInput::InterpretNode n |
isSinkNode(n, kind, _) and n.asNode() = node // TODO
)
}
}
import Cached
private predicate interpretSummary(
Function f, string input, string output, string kind, string provenance
) {
exists(
string namespace, string type, boolean subtypes, string name, string signature, string ext
|
summaryModel(namespace, type, subtypes, name, signature, ext, input, output, kind, provenance) and
f = interpretElement(namespace, type, subtypes, name, signature, ext)
)
}
// adapter class for converting Mad summaries to `SummarizedCallable`s
private class SummarizedCallableAdapter extends SummarizedCallable {
SummarizedCallableAdapter() { interpretSummary(this, _, _, _, _) }
private predicate relevantSummaryElementManual(string input, string output, string kind) {
exists(Provenance provenance |
interpretSummary(this, input, output, kind, provenance) and
provenance.isManual()
)
}
private predicate relevantSummaryElementGenerated(string input, string output, string kind) {
exists(Provenance provenance |
interpretSummary(this, input, output, kind, provenance) and
provenance.isGenerated()
)
}
override predicate propagatesFlow(
string input, string output, boolean preservesValue, string model
) {
exists(string kind |
this.relevantSummaryElementManual(input, output, kind)
or
not this.relevantSummaryElementManual(_, _, _) and
this.relevantSummaryElementGenerated(input, output, kind)
|
if kind = "value" then preservesValue = true else preservesValue = false
) and
model = "" // TODO
}
override predicate hasProvenance(Provenance provenance) {
interpretSummary(this, _, _, _, provenance)
}
}
// adapter class for converting Mad neutrals to `NeutralCallable`s
private class NeutralCallableAdapter extends NeutralCallable {
string kind;
string provenance_;
NeutralCallableAdapter() {
// Neutral models have not been implemented for CPP.
none() and
exists(this) and
exists(kind) and
exists(provenance_)
}
override string getKind() { result = kind }
override predicate hasProvenance(Provenance provenance) { provenance = provenance_ }
}