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2 Commits

Author SHA1 Message Date
Max Schaefer
7767a2951e Update qhelp for py/path-injection. 2023-11-16 14:13:45 +00:00
Max Schaefer
51f7645729 Update qhelp for js/path-injection. 2023-11-16 14:13:45 +00:00
3258 changed files with 93307 additions and 208851 deletions

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@@ -31,12 +31,3 @@ updates:
- "golang.org/x/*"
reviewers:
- "github/codeql-go"
- package-ecosystem: "gomod"
directory: "go/ql/test"
schedule:
interval: "monthly"
ignore:
- dependency-name: "*"
reviewers:
- "github/codeql-go"

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@@ -9,42 +9,26 @@ on:
- "*/ql/lib/**/*.ql"
- "*/ql/lib/**/*.qll"
- "*/ql/lib/**/*.yml"
- "shared/**/*.ql"
- "shared/**/*.qll"
- "!**/experimental/**"
- "!ql/**"
- ".github/workflows/check-change-note.yml"
jobs:
check-change-note:
env:
REPO: ${{ github.repository }}
PULL_REQUEST_NUMBER: ${{ github.event.number }}
GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
runs-on: ubuntu-latest
steps:
- name: Fail if no change note found. To fix, either add one, or add the `no-change-note-required` label.
if: |
github.event.pull_request.draft == false &&
!contains(github.event.pull_request.labels.*.name, 'no-change-note-required')
env:
GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
run: |
change_note_files=$(gh api "repos/$REPO/pulls/$PULL_REQUEST_NUMBER/files" --paginate --jq '.[].filename | select(test("/change-notes/.*[.]md$"))')
if [ -z "$change_note_files" ]; then
echo "No change note found. Either add one, or add the 'no-change-note-required' label."
exit 1
fi
echo "Change notes found:"
echo "$change_note_files"
gh api 'repos/${{github.repository}}/pulls/${{github.event.number}}/files' --paginate --jq 'any(.[].filename ; test("/change-notes/.*[.]md$"))' |
grep true -c
- name: Fail if the change note filename doesn't match the expected format. The file name must be of the form 'YYYY-MM-DD.md', 'YYYY-MM-DD-{title}.md', where '{title}' is arbitrary text, or released/x.y.z.md for released change-notes
env:
GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
run: |
bad_change_note_file_names=$(gh api "repos/$REPO/pulls/$PULL_REQUEST_NUMBER/files" --paginate --jq '[.[].filename | select(test("/change-notes/.*[.]md$"))][] | select((test("/change-notes/[0-9]{4}-[0-9]{2}-[0-9]{2}.*[.]md$") or test("/change-notes/released/[0-9]*[.][0-9]*[.][0-9]*[.]md$")) | not)')
if [ -n "$bad_change_note_file_names" ]; then
echo "The following change note file names are invalid:"
echo "$bad_change_note_file_names"
exit 1
fi
gh api 'repos/${{github.repository}}/pulls/${{github.event.number}}/files' --paginate --jq '[.[].filename | select(test("/change-notes/.*[.]md$"))] | all(test("/change-notes/[0-9]{4}-[0-9]{2}-[0-9]{2}.*[.]md$") or test("/change-notes/released/[0-9]*[.][0-9]*[.][0-9]*[.]md$"))' |
grep true -c

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@@ -91,7 +91,7 @@ jobs:
run: |
# Generate (Asp)NetCore stubs
STUBS_PATH=stubs_output
python3 scripts/stubs/make_stubs_nuget.py webapp Swashbuckle.AspNetCore.Swagger 6.5.0 "$STUBS_PATH"
python3 ql/src/Stubs/make_stubs_nuget.py webapp Swashbuckle.AspNetCore.Swagger 6.5.0 "$STUBS_PATH"
rm -rf ql/test/resources/stubs/_frameworks
# Update existing stubs in the repo with the freshly generated ones
mv "$STUBS_PATH/output/stubs/_frameworks" ql/test/resources/stubs/

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@@ -89,32 +89,9 @@ jobs:
- name: Save PR number
run: |
mkdir -p pr
echo ${PR_NUMBER} > pr/NR
env:
PR_NUMBER: ${{ github.event.pull_request.number }}
echo ${{ github.event.pull_request.number }} > pr/NR
- name: Upload PR number
uses: actions/upload-artifact@v3
with:
name: pr
path: pr/
- name: Save comment ID (if it exists)
run: |
# Find the latest comment starting with COMMENT_PREFIX
COMMENT_PREFIX=":warning: The head of this PR and the base branch were compared for differences in the framework coverage reports."
COMMENT_ID=$(gh api "repos/${GITHUB_REPOSITORY}/issues/${PR_NUMBER}/comments" --paginate | jq --arg prefix "${COMMENT_PREFIX}" 'map(select(.body|startswith($prefix)) | .id) | max // empty')
if [[ -z ${COMMENT_ID} ]]
then
echo "Comment not found. Not uploading 'comment/ID' artifact."
else
mkdir -p comment
echo ${COMMENT_ID} > comment/ID
fi
env:
GITHUB_TOKEN: ${{ github.token }}
PR_NUMBER: ${{ github.event.pull_request.number }}
- name: Upload comment ID (if it exists)
uses: actions/upload-artifact@v3
with:
name: comment
path: comment/
if-no-files-found: ignore

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@@ -6,7 +6,7 @@ provide:
- "*/ql/consistency-queries/qlpack.yml"
- "*/ql/automodel/src/qlpack.yml"
- "*/ql/automodel/test/qlpack.yml"
- "shared/**/qlpack.yml"
- "shared/*/qlpack.yml"
- "cpp/ql/test/query-tests/Security/CWE/CWE-190/semmle/tainted/qlpack.yml"
- "go/ql/config/legacy-support/qlpack.yml"
- "go/build/codeql-extractor-go/codeql-extractor.yml"
@@ -29,7 +29,6 @@ provide:
- "swift/extractor-pack/codeql-extractor.yml"
- "swift/integration-tests/qlpack.yml"
- "ql/extractor-pack/codeql-extractor.yml"
- ".github/codeql/extensions/**/codeql-pack.yml"
versionPolicies:
default:

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@@ -145,9 +145,9 @@ namespace Semmle.Autobuild.Cpp.Tests
bool IBuildActions.IsMacOs() => IsMacOs;
public bool IsRunningOnAppleSilicon { get; set; }
public bool IsArm { get; set; }
bool IBuildActions.IsRunningOnAppleSilicon() => IsRunningOnAppleSilicon;
bool IBuildActions.IsArm() => IsArm;
string IBuildActions.PathCombine(params string[] parts)
{

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@@ -1,19 +0,0 @@
class BuiltinType extends @builtintype {
string toString() { none() }
}
from BuiltinType type, string name, int kind, int kind_new, int size, int sign, int alignment
where
builtintypes(type, name, kind, size, sign, alignment) and
if
type instanceof @fp16 or
type instanceof @std_bfloat16 or
type instanceof @std_float16 or
type instanceof @complex_std_float32 or
type instanceof @complex_float32x or
type instanceof @complex_std_float64 or
type instanceof @complex_float64x or
type instanceof @complex_std_float128
then kind_new = 2
else kind_new = kind
select type, name, kind_new, size, sign, alignment

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@@ -1,3 +0,0 @@
description: Introduce new floating-point types from C23 and C++23
compatibility: backwards
builtintypes.rel: run builtintypes.qlo

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@@ -1,2 +0,0 @@
description: Removed @assignpaddexpr and @assignpsubexpr from @assign_bitwise_expr
compatibility: full

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@@ -1,3 +0,0 @@
description: Introduce extractor version numbers
compatibility: breaking
extractor_version.rel: delete

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@@ -1,25 +1,3 @@
## 0.11.0
### Breaking Changes
* The `Container` and `Folder` classes now derive from `ElementBase` instead of `Locatable`, and no longer expose the `getLocation` predicate. Use `getURL` instead.
### New Features
* Added a new class `AdditionalCallTarget` for specifying additional call targets.
### Minor Analysis Improvements
* More field accesses are identified as `ImplicitThisFieldAccess`.
* Added support for new floating-point types in C23 and C++23.
## 0.10.1
### Minor Analysis Improvements
* Deleted the deprecated `AnalysedString` class, use the new name `AnalyzedString`.
* Deleted the deprecated `isBarrierGuard` predicate from the dataflow library and its uses, use `isBarrier` and the `BarrierGuard` module instead.
## 0.10.0
### Minor Analysis Improvements

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@@ -1,6 +1,5 @@
## 0.10.1
### Minor Analysis Improvements
---
category: minorAnalysis
---
* Deleted the deprecated `AnalysedString` class, use the new name `AnalyzedString`.
* Deleted the deprecated `isBarrierGuard` predicate from the dataflow library and its uses, use `isBarrier` and the `BarrierGuard` module instead.

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@@ -1,4 +0,0 @@
---
category: minorAnalysis
---
* Added taint models for `realloc` and related functions.

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@@ -1,4 +0,0 @@
---
category: breaking
---
* The expressions `AssignPointerAddExpr` and `AssignPointerSubExpr` are no longer subtypes of `AssignBitwiseOperation`.

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@@ -1,4 +0,0 @@
---
category: minorAnalysis
---
* Added SQL API models for `ODBC`.

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@@ -1,4 +0,0 @@
---
category: minorAnalysis
---
* Added models for the `sprintf` variants from the `StrSafe.h` header.

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@@ -1,4 +0,0 @@
---
category: minorAnalysis
---
* Added models for `strlcpy` and `strlcat`.

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@@ -1,4 +0,0 @@
---
category: minorAnalysis
---
* The "Returning stack-allocated memory" (`cpp/return-stack-allocated-memory`) query now also detects returning stack-allocated memory allocated by calls to `alloca`, `strdupa`, and `strndupa`.

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@@ -1,14 +0,0 @@
## 0.11.0
### Breaking Changes
* The `Container` and `Folder` classes now derive from `ElementBase` instead of `Locatable`, and no longer expose the `getLocation` predicate. Use `getURL` instead.
### New Features
* Added a new class `AdditionalCallTarget` for specifying additional call targets.
### Minor Analysis Improvements
* More field accesses are identified as `ImplicitThisFieldAccess`.
* Added support for new floating-point types in C23 and C++23.

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@@ -1,2 +1,2 @@
---
lastReleaseVersion: 0.11.0
lastReleaseVersion: 0.10.0

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@@ -1,5 +1,5 @@
name: codeql/cpp-all
version: 0.11.1-dev
version: 0.10.1-dev
groups: cpp
dbscheme: semmlecode.cpp.dbscheme
extractor: cpp
@@ -7,7 +7,6 @@ library: true
upgrades: upgrades
dependencies:
codeql/dataflow: ${workspace}
codeql/rangeanalysis: ${workspace}
codeql/ssa: ${workspace}
codeql/tutorial: ${workspace}
codeql/util: ${workspace}

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@@ -32,7 +32,7 @@ private module Input implements InputSig {
private module Impl = Make<Input>;
/** A file or folder. */
class Container extends ElementBase, Impl::Container {
class Container extends Locatable, Impl::Container {
override string toString() { result = Impl::Container.super.toString() }
}
@@ -47,6 +47,11 @@ class Container extends ElementBase, Impl::Container {
* To get the full path, use `getAbsolutePath`.
*/
class Folder extends Container, Impl::Folder {
override Location getLocation() {
result.getContainer() = this and
result.hasLocationInfo(_, 0, 0, 0, 0)
}
override string getAPrimaryQlClass() { result = "Folder" }
}
@@ -62,7 +67,7 @@ class Folder extends Container, Impl::Folder {
* The base name further decomposes into the _stem_ and _extension_ -- see
* `getStem` and `getExtension`. To get the full path, use `getAbsolutePath`.
*/
class File extends Container, Locatable, Impl::File {
class File extends Container, Impl::File {
override string getAPrimaryQlClass() { result = "File" }
override Location getLocation() {

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@@ -819,30 +819,6 @@ private predicate floatingPointTypeMapping(
or
// _Complex _Float16
kind = 53 and base = 2 and domain = TComplexDomain() and realKind = 52 and extended = false
or
// __fp16
kind = 54 and base = 2 and domain = TRealDomain() and realKind = 54 and extended = false
or
// __bf16
kind = 55 and base = 2 and domain = TRealDomain() and realKind = 55 and extended = false
or
// std::float16_t
kind = 56 and base = 2 and domain = TRealDomain() and realKind = 56 and extended = false
or
// _Complex _Float32
kind = 57 and base = 2 and domain = TComplexDomain() and realKind = 45 and extended = false
or
// _Complex _Float32x
kind = 58 and base = 2 and domain = TComplexDomain() and realKind = 46 and extended = true
or
// _Complex _Float64
kind = 59 and base = 2 and domain = TComplexDomain() and realKind = 47 and extended = false
or
// _Complex _Float64x
kind = 60 and base = 2 and domain = TComplexDomain() and realKind = 48 and extended = true
or
// _Complex _Float128
kind = 61 and base = 2 and domain = TComplexDomain() and realKind = 49 and extended = false
}
/**

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@@ -306,13 +306,15 @@ private predicate exprHasReferenceConversion(Expr e) { referenceConversion(e.get
* }
* };
* ```
* Note: the C++ front-end often automatically desugars `field` to
* `this->field`, so most accesses of `this->field` are instances
* of `PointerFieldAccess` (with `ThisExpr` as the qualifier), not
* `ImplicitThisFieldAccess`.
*/
class ImplicitThisFieldAccess extends FieldAccess {
override string getAPrimaryQlClass() { result = "ImplicitThisFieldAccess" }
ImplicitThisFieldAccess() {
this.getQualifier().(ThisExpr).isCompilerGenerated() or not exists(this.getQualifier())
}
ImplicitThisFieldAccess() { not exists(this.getQualifier()) }
}
/**
@@ -330,7 +332,7 @@ class PointerToFieldLiteral extends ImplicitThisFieldAccess {
// access without a qualifier. The only other unqualified field accesses it
// emits are for compiler-generated constructors and destructors. When we
// filter those out, there are only pointer-to-field literals left.
not this.isCompilerGenerated() and not exists(this.getQualifier())
not this.isCompilerGenerated()
}
override predicate isConstant() { any() }

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@@ -1,15 +0,0 @@
/**
* INTERNAL: Do not use. Provides predicates for getting the CodeQL and frontend
* version used during database extraction.
*/
/** Get the extractor CodeQL version */
string getExtractorCodeQLVersion() { extractor_version(result, _) }
/** Get the extractor frontend version */
string getExtractorFrontendVersion() { extractor_version(_, result) }
predicate isExtractorFrontendVersion65OrHigher() {
// Version numbers we not included in the database before 6.5.
exists(getExtractorCodeQLVersion())
}

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@@ -31,11 +31,6 @@ abstract class MustFlowConfiguration extends string {
*/
abstract predicate isSink(Operand sink);
/**
* Holds if data flow through `instr` is prohibited.
*/
predicate isBarrier(Instruction instr) { none() }
/**
* Holds if the additional flow step from `node1` to `node2` must be taken
* into account in the analysis.
@@ -53,21 +48,18 @@ abstract class MustFlowConfiguration extends string {
*/
final predicate hasFlowPath(MustFlowPathNode source, MustFlowPathSink sink) {
this.isSource(source.getInstruction()) and
source.getASuccessor*() = sink
source.getASuccessor+() = sink
}
}
/** Holds if `node` flows from a source. */
pragma[nomagic]
private predicate flowsFromSource(Instruction node, MustFlowConfiguration config) {
not config.isBarrier(node) and
(
config.isSource(node)
or
exists(Instruction mid |
step(mid, node, config) and
flowsFromSource(mid, pragma[only_bind_into](config))
)
config.isSource(node)
or
exists(Instruction mid |
step(mid, node, config) and
flowsFromSource(mid, pragma[only_bind_into](config))
)
}

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@@ -7,12 +7,9 @@ private import DataFlowImplCommon as DataFlowImplCommon
/**
* Gets a function that might be called by `call`.
*
* This predicate does not take additional call targets
* from `AdditionalCallTarget` into account.
*/
cached
DataFlowCallable defaultViableCallable(DataFlowCall call) {
DataFlowCallable viableCallable(DataFlowCall call) {
DataFlowImplCommon::forceCachingInSameStage() and
result = call.getStaticCallTarget()
or
@@ -32,17 +29,6 @@ DataFlowCallable defaultViableCallable(DataFlowCall call) {
result = call.(VirtualDispatch::DataSensitiveCall).resolve()
}
/**
* Gets a function that might be called by `call`.
*/
cached
DataFlowCallable viableCallable(DataFlowCall call) {
result = defaultViableCallable(call)
or
// Additional call targets
result = any(AdditionalCallTarget additional).viableTarget(call.getUnconvertedResultExpression())
}
/**
* Provides virtual dispatch support compatible with the original
* implementation of `semmle.code.cpp.security.TaintTracking`.

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@@ -81,14 +81,6 @@ class Node0Impl extends TIRDataFlowNode0 {
/** Gets the operands corresponding to this node, if any. */
Operand asOperand() { result = this.(OperandNode0).getOperand() }
/** Gets the location of this node. */
final Location getLocation() { result = this.getLocationImpl() }
/** INTERNAL: Do not use. */
Location getLocationImpl() {
none() // overridden by subclasses
}
/** INTERNAL: Do not use. */
string toStringImpl() {
none() // overridden by subclasses
@@ -139,15 +131,9 @@ abstract class InstructionNode0 extends Node0Impl {
override DataFlowType getType() { result = getInstructionType(instr, _) }
override string toStringImpl() {
if instr.(InitializeParameterInstruction).getIRVariable() instanceof IRThisVariable
then result = "this"
else result = instr.getAst().toString()
}
override Location getLocationImpl() {
if exists(instr.getAst().getLocation())
then result = instr.getAst().getLocation()
else result instanceof UnknownDefaultLocation
// This predicate is overridden in subclasses. This default implementation
// does not use `Instruction.toString` because that's expensive to compute.
result = instr.getOpcode().toString()
}
final override predicate isGLValue() { exists(getInstructionType(instr, true)) }
@@ -187,17 +173,7 @@ abstract class OperandNode0 extends Node0Impl {
override DataFlowType getType() { result = getOperandType(op, _) }
override string toStringImpl() {
if op.getDef().(InitializeParameterInstruction).getIRVariable() instanceof IRThisVariable
then result = "this"
else result = op.getDef().getAst().toString()
}
override Location getLocationImpl() {
if exists(op.getDef().getAst().getLocation())
then result = op.getDef().getAst().getLocation()
else result instanceof UnknownDefaultLocation
}
override string toStringImpl() { result = op.toString() }
final override predicate isGLValue() { exists(getOperandType(op, true)) }
}
@@ -656,20 +632,20 @@ predicate jumpStep(Node n1, Node n2) {
v = globalUse.getVariable() and
n1.(FinalGlobalValue).getGlobalUse() = globalUse
|
globalUse.getIndirection() = 1 and
globalUse.getIndirectionIndex() = 1 and
v = n2.asVariable()
or
v = n2.asIndirectVariable(globalUse.getIndirection())
v = n2.asIndirectVariable(globalUse.getIndirectionIndex())
)
or
exists(Ssa::GlobalDef globalDef |
v = globalDef.getVariable() and
n2.(InitialGlobalValue).getGlobalDef() = globalDef
|
globalDef.getIndirection() = 1 and
globalDef.getIndirectionIndex() = 1 and
v = n1.asVariable()
or
v = n1.asIndirectVariable(globalDef.getIndirection())
v = n1.asIndirectVariable(globalDef.getIndirectionIndex())
)
)
}

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@@ -14,7 +14,6 @@ private import DataFlowPrivate
private import ModelUtil
private import SsaInternals as Ssa
private import DataFlowImplCommon as DataFlowImplCommon
private import codeql.util.Unit
/**
* The IR dataflow graph consists of the following nodes:
@@ -44,12 +43,11 @@ private newtype TIRDataFlowNode =
TIndirectArgumentOutNode(ArgumentOperand operand, int indirectionIndex) {
Ssa::isModifiableByCall(operand, indirectionIndex)
} or
TRawIndirectOperand0(Node0Impl node, int indirectionIndex) {
Ssa::hasRawIndirectOperand(node.asOperand(), indirectionIndex)
TRawIndirectOperand(Operand op, int indirectionIndex) {
Ssa::hasRawIndirectOperand(op, indirectionIndex)
} or
TRawIndirectInstruction0(Node0Impl node, int indirectionIndex) {
not exists(node.asOperand()) and
Ssa::hasRawIndirectInstruction(node.asInstruction(), indirectionIndex)
TRawIndirectInstruction(Instruction instr, int indirectionIndex) {
Ssa::hasRawIndirectInstruction(instr, indirectionIndex)
} or
TFinalParameterNode(Parameter p, int indirectionIndex) {
exists(Ssa::FinalParameterUse use |
@@ -432,10 +430,6 @@ private class Node0 extends Node, TNode0 {
override Declaration getFunction() { result = node.getFunction() }
override Location getLocationImpl() { result = node.getLocation() }
override string toStringImpl() { result = node.toString() }
override DataFlowType getType() { result = node.getType() }
override predicate isGLValue() { node.isGLValue() }
@@ -452,6 +446,18 @@ class InstructionNode extends Node0 {
/** Gets the instruction corresponding to this node. */
Instruction getInstruction() { result = instr }
override Location getLocationImpl() {
if exists(instr.getAst().getLocation())
then result = instr.getAst().getLocation()
else result instanceof UnknownDefaultLocation
}
override string toStringImpl() {
if instr.(InitializeParameterInstruction).getIRVariable() instanceof IRThisVariable
then result = "this"
else result = instr.getAst().toString()
}
}
/**
@@ -465,6 +471,18 @@ class OperandNode extends Node, Node0 {
/** Gets the operand corresponding to this node. */
Operand getOperand() { result = op }
override Location getLocationImpl() {
if exists(op.getDef().getAst().getLocation())
then result = op.getDef().getAst().getLocation()
else result instanceof UnknownDefaultLocation
}
override string toStringImpl() {
if op.getDef().(InitializeParameterInstruction).getIRVariable() instanceof IRThisVariable
then result = "this"
else result = op.getDef().getAst().toString()
}
}
/**
@@ -899,146 +917,48 @@ Type getTypeImpl(Type t, int indirectionIndex) {
result instanceof UnknownType
}
private module RawIndirectNodes {
/**
* INTERNAL: Do not use.
*
* A node that represents the indirect value of an operand in the IR
* after `index` number of loads.
*/
private class RawIndirectOperand0 extends Node, TRawIndirectOperand0 {
Node0Impl node;
int indirectionIndex;
/**
* INTERNAL: Do not use.
*
* A node that represents the indirect value of an operand in the IR
* after `index` number of loads.
*/
class RawIndirectOperand extends Node, TRawIndirectOperand {
Operand operand;
int indirectionIndex;
RawIndirectOperand0() { this = TRawIndirectOperand0(node, indirectionIndex) }
RawIndirectOperand() { this = TRawIndirectOperand(operand, indirectionIndex) }
/** Gets the underlying instruction. */
Operand getOperand() { result = node.asOperand() }
/** Gets the underlying instruction. */
Operand getOperand() { result = operand }
/** Gets the underlying indirection index. */
int getIndirectionIndex() { result = indirectionIndex }
/** Gets the underlying indirection index. */
int getIndirectionIndex() { result = indirectionIndex }
override Declaration getFunction() {
result = this.getOperand().getDef().getEnclosingFunction()
}
override Declaration getFunction() { result = this.getOperand().getDef().getEnclosingFunction() }
override Declaration getEnclosingCallable() { result = this.getFunction() }
override Declaration getEnclosingCallable() { result = this.getFunction() }
override DataFlowType getType() {
exists(int sub, DataFlowType type, boolean isGLValue |
type = getOperandType(this.getOperand(), isGLValue) and
if isGLValue = true then sub = 1 else sub = 0
|
result = getTypeImpl(type.getUnspecifiedType(), indirectionIndex - sub)
)
}
final override Location getLocationImpl() {
if exists(this.getOperand().getLocation())
then result = this.getOperand().getLocation()
else result instanceof UnknownDefaultLocation
}
override string toStringImpl() {
result = operandNode(this.getOperand()).toStringImpl() + " indirection"
}
override DataFlowType getType() {
exists(int sub, DataFlowType type, boolean isGLValue |
type = getOperandType(operand, isGLValue) and
if isGLValue = true then sub = 1 else sub = 0
|
result = getTypeImpl(type.getUnspecifiedType(), indirectionIndex - sub)
)
}
/**
* INTERNAL: Do not use.
*
* A node that represents the indirect value of an instruction in the IR
* after `index` number of loads.
*/
private class RawIndirectInstruction0 extends Node, TRawIndirectInstruction0 {
Node0Impl node;
int indirectionIndex;
RawIndirectInstruction0() { this = TRawIndirectInstruction0(node, indirectionIndex) }
/** Gets the underlying instruction. */
Instruction getInstruction() { result = node.asInstruction() }
/** Gets the underlying indirection index. */
int getIndirectionIndex() { result = indirectionIndex }
override Declaration getFunction() { result = this.getInstruction().getEnclosingFunction() }
override Declaration getEnclosingCallable() { result = this.getFunction() }
override DataFlowType getType() {
exists(int sub, DataFlowType type, boolean isGLValue |
type = getInstructionType(this.getInstruction(), isGLValue) and
if isGLValue = true then sub = 1 else sub = 0
|
result = getTypeImpl(type.getUnspecifiedType(), indirectionIndex - sub)
)
}
final override Location getLocationImpl() {
if exists(this.getInstruction().getLocation())
then result = this.getInstruction().getLocation()
else result instanceof UnknownDefaultLocation
}
override string toStringImpl() {
result = instructionNode(this.getInstruction()).toStringImpl() + " indirection"
}
final override Location getLocationImpl() {
if exists(this.getOperand().getLocation())
then result = this.getOperand().getLocation()
else result instanceof UnknownDefaultLocation
}
/**
* INTERNAL: Do not use.
*
* A node that represents the indirect value of an operand in the IR
* after a number of loads.
*/
class RawIndirectOperand extends Node {
int indirectionIndex;
Operand operand;
RawIndirectOperand() {
exists(Node0Impl node | operand = node.asOperand() |
this = TRawIndirectOperand0(node, indirectionIndex)
or
this = TRawIndirectInstruction0(node, indirectionIndex)
)
}
/** Gets the operand associated with this node. */
Operand getOperand() { result = operand }
/** Gets the underlying indirection index. */
int getIndirectionIndex() { result = indirectionIndex }
}
/**
* INTERNAL: Do not use.
*
* A node that represents the indirect value of an instruction in the IR
* after a number of loads.
*/
class RawIndirectInstruction extends Node {
int indirectionIndex;
Instruction instr;
RawIndirectInstruction() {
exists(Node0Impl node | instr = node.asInstruction() |
this = TRawIndirectOperand0(node, indirectionIndex)
or
this = TRawIndirectInstruction0(node, indirectionIndex)
)
}
/** Gets the instruction associated with this node. */
Instruction getInstruction() { result = instr }
/** Gets the underlying indirection index. */
int getIndirectionIndex() { result = indirectionIndex }
override string toStringImpl() {
result = operandNode(this.getOperand()).toStringImpl() + " indirection"
}
}
import RawIndirectNodes
/**
* INTERNAL: do not use.
*
@@ -1100,6 +1020,48 @@ class UninitializedNode extends Node {
LocalVariable getLocalVariable() { result = v }
}
/**
* INTERNAL: Do not use.
*
* A node that represents the indirect value of an instruction in the IR
* after `index` number of loads.
*/
class RawIndirectInstruction extends Node, TRawIndirectInstruction {
Instruction instr;
int indirectionIndex;
RawIndirectInstruction() { this = TRawIndirectInstruction(instr, indirectionIndex) }
/** Gets the underlying instruction. */
Instruction getInstruction() { result = instr }
/** Gets the underlying indirection index. */
int getIndirectionIndex() { result = indirectionIndex }
override Declaration getFunction() { result = this.getInstruction().getEnclosingFunction() }
override Declaration getEnclosingCallable() { result = this.getFunction() }
override DataFlowType getType() {
exists(int sub, DataFlowType type, boolean isGLValue |
type = getInstructionType(instr, isGLValue) and
if isGLValue = true then sub = 1 else sub = 0
|
result = getTypeImpl(type.getUnspecifiedType(), indirectionIndex - sub)
)
}
final override Location getLocationImpl() {
if exists(this.getInstruction().getLocation())
then result = this.getInstruction().getLocation()
else result instanceof UnknownDefaultLocation
}
override string toStringImpl() {
result = instructionNode(this.getInstruction()).toStringImpl() + " indirection"
}
}
private module GetConvertedResultExpression {
private import semmle.code.cpp.ir.implementation.raw.internal.TranslatedExpr
private import semmle.code.cpp.ir.implementation.raw.internal.InstructionTag
@@ -1637,29 +1599,26 @@ private module Cached {
predicate localFlowStep(Node nodeFrom, Node nodeTo) { simpleLocalFlowStep(nodeFrom, nodeTo) }
private predicate indirectionOperandFlow(RawIndirectOperand nodeFrom, Node nodeTo) {
nodeFrom != nodeTo and
(
// Reduce the indirection count by 1 if we're passing through a `LoadInstruction`.
exists(int ind, LoadInstruction load |
hasOperandAndIndex(nodeFrom, load.getSourceAddressOperand(), ind) and
nodeHasInstruction(nodeTo, load, ind - 1)
)
or
// If an operand flows to an instruction, then the indirection of
// the operand also flows to the indirection of the instruction.
exists(Operand operand, Instruction instr, int indirectionIndex |
simpleInstructionLocalFlowStep(operand, instr) and
hasOperandAndIndex(nodeFrom, operand, pragma[only_bind_into](indirectionIndex)) and
hasInstructionAndIndex(nodeTo, instr, pragma[only_bind_into](indirectionIndex))
)
or
// If there's indirect flow to an operand, then there's also indirect
// flow to the operand after applying some pointer arithmetic.
exists(PointerArithmeticInstruction pointerArith, int indirectionIndex |
hasOperandAndIndex(nodeFrom, pointerArith.getAnOperand(),
pragma[only_bind_into](indirectionIndex)) and
hasInstructionAndIndex(nodeTo, pointerArith, pragma[only_bind_into](indirectionIndex))
)
// Reduce the indirection count by 1 if we're passing through a `LoadInstruction`.
exists(int ind, LoadInstruction load |
hasOperandAndIndex(nodeFrom, load.getSourceAddressOperand(), ind) and
nodeHasInstruction(nodeTo, load, ind - 1)
)
or
// If an operand flows to an instruction, then the indirection of
// the operand also flows to the indirection of the instruction.
exists(Operand operand, Instruction instr, int indirectionIndex |
simpleInstructionLocalFlowStep(operand, instr) and
hasOperandAndIndex(nodeFrom, operand, pragma[only_bind_into](indirectionIndex)) and
hasInstructionAndIndex(nodeTo, instr, pragma[only_bind_into](indirectionIndex))
)
or
// If there's indirect flow to an operand, then there's also indirect
// flow to the operand after applying some pointer arithmetic.
exists(PointerArithmeticInstruction pointerArith, int indirectionIndex |
hasOperandAndIndex(nodeFrom, pointerArith.getAnOperand(),
pragma[only_bind_into](indirectionIndex)) and
hasInstructionAndIndex(nodeTo, pointerArith, pragma[only_bind_into](indirectionIndex))
)
}
@@ -1685,7 +1644,6 @@ private module Cached {
private predicate indirectionInstructionFlow(
RawIndirectInstruction nodeFrom, IndirectOperand nodeTo
) {
nodeFrom != nodeTo and
// If there's flow from an instruction to an operand, then there's also flow from the
// indirect instruction to the indirect operand.
exists(Operand operand, Instruction instr, int indirectionIndex |
@@ -2279,43 +2237,3 @@ module InstructionBarrierGuard<instructionGuardChecksSig/3 instructionGuardCheck
)
}
}
/**
* A unit class for adding additional call steps.
*
* Extend this class to add additional call steps to the data flow graph.
*
* For example, if the following subclass is added:
* ```ql
* class MyAdditionalCallTarget extends DataFlow::AdditionalCallTarget {
* override Function viableTarget(Call call) {
* call.getTarget().hasName("f") and
* result.hasName("g")
* }
* }
* ```
* then flow from `source()` to `x` in `sink(x)` is reported in the following example:
* ```cpp
* void sink(int);
* int source();
* void f(int);
*
* void g(int x) {
* sink(x);
* }
*
* void test() {
* int x = source();
* f(x);
* }
* ```
*
* Note: To prevent reevaluation of cached dataflow-related predicates any
* subclass of `AdditionalCallTarget` must be imported in all dataflow queries.
*/
class AdditionalCallTarget extends Unit {
/**
* Gets a viable target for `call`.
*/
abstract DataFlowCallable viableTarget(Call call);
}

View File

@@ -31,35 +31,26 @@ DataFlow::Node callInput(CallInstruction call, FunctionInput input) {
)
}
/**
* Gets the node that represents the output of `call` with kind `output` at
* indirection index `indirectionIndex`.
*/
private Node callOutputWithIndirectionIndex(
CallInstruction call, FunctionOutput output, int indirectionIndex
) {
// The return value
simpleOutNode(result, call) and
output.isReturnValue() and
indirectionIndex = 0
or
// The side effect of a call on the value pointed to by an argument or qualifier
exists(int index |
result.(IndirectArgumentOutNode).getArgumentIndex() = index and
result.(IndirectArgumentOutNode).getIndirectionIndex() = indirectionIndex - 1 and
result.(IndirectArgumentOutNode).getCallInstruction() = call and
output.isParameterDerefOrQualifierObject(index, indirectionIndex - 1)
)
or
result = getIndirectReturnOutNode(call, indirectionIndex) and
output.isReturnValueDeref(indirectionIndex)
}
/**
* Gets the instruction that holds the `output` for `call`.
*/
Node callOutput(CallInstruction call, FunctionOutput output) {
result = callOutputWithIndirectionIndex(call, output, _)
// The return value
simpleOutNode(result, call) and
output.isReturnValue()
or
// The side effect of a call on the value pointed to by an argument or qualifier
exists(int index, int indirectionIndex |
result.(IndirectArgumentOutNode).getArgumentIndex() = index and
result.(IndirectArgumentOutNode).getIndirectionIndex() = indirectionIndex and
result.(IndirectArgumentOutNode).getCallInstruction() = call and
output.isParameterDerefOrQualifierObject(index, indirectionIndex)
)
or
exists(int ind |
result = getIndirectReturnOutNode(call, ind) and
output.isReturnValueDeref(ind)
)
}
DataFlow::Node callInput(CallInstruction call, FunctionInput input, int d) {
@@ -85,15 +76,19 @@ private IndirectReturnOutNode getIndirectReturnOutNode(CallInstruction call, int
*/
bindingset[d]
Node callOutput(CallInstruction call, FunctionOutput output, int d) {
exists(DataFlow::Node n, int indirectionIndex |
n = callOutputWithIndirectionIndex(call, output, indirectionIndex) and d > 0
|
exists(DataFlow::Node n | n = callOutput(call, output) and d > 0 |
// The return value
result = callOutputWithIndirectionIndex(call, output, indirectionIndex + d)
result = getIndirectReturnOutNode(n.asInstruction(), d)
or
// If there isn't an indirect out node for the call with indirection `d` then
// we conflate this with the underlying `CallInstruction`.
not exists(getIndirectReturnOutNode(call, indirectionIndex + d)) and
not exists(getIndirectReturnOutNode(call, d)) and
n = result
or
// The side effect of a call on the value pointed to by an argument or qualifier
exists(Operand operand, int indirectionIndex |
Ssa::outNodeHasAddressAndIndex(n, operand, indirectionIndex) and
Ssa::outNodeHasAddressAndIndex(result, operand, indirectionIndex + d)
)
)
}

View File

@@ -113,12 +113,22 @@ private newtype TDefOrUseImpl =
TGlobalUse(GlobalLikeVariable v, IRFunction f, int indirectionIndex) {
// Represents a final "use" of a global variable to ensure that
// the assignment to a global variable isn't ruled out as dead.
isGlobalUse(v, f, _, indirectionIndex)
exists(VariableAddressInstruction vai, int defIndex |
vai.getEnclosingIRFunction() = f and
vai.getAstVariable() = v and
isDef(_, _, _, vai, _, defIndex) and
indirectionIndex = [0 .. defIndex] + 1
)
} or
TGlobalDefImpl(GlobalLikeVariable v, IRFunction f, int indirectionIndex) {
// Represents the initial "definition" of a global variable when entering
// a function body.
isGlobalDefImpl(v, f, _, indirectionIndex)
exists(VariableAddressInstruction vai |
vai.getEnclosingIRFunction() = f and
vai.getAstVariable() = v and
isUse(_, _, vai, _, indirectionIndex) and
not isDef(_, _, vai.getAUse(), _, _, _)
)
} or
TIteratorDef(
Operand iteratorDerefAddress, BaseSourceVariableInstruction container, int indirectionIndex
@@ -140,27 +150,6 @@ private newtype TDefOrUseImpl =
)
}
private predicate isGlobalUse(
GlobalLikeVariable v, IRFunction f, int indirection, int indirectionIndex
) {
exists(VariableAddressInstruction vai |
vai.getEnclosingIRFunction() = f and
vai.getAstVariable() = v and
isDef(_, _, _, vai, indirection, indirectionIndex)
)
}
private predicate isGlobalDefImpl(
GlobalLikeVariable v, IRFunction f, int indirection, int indirectionIndex
) {
exists(VariableAddressInstruction vai |
vai.getEnclosingIRFunction() = f and
vai.getAstVariable() = v and
isUse(_, _, vai, indirection, indirectionIndex) and
not isDef(_, _, _, vai, _, indirectionIndex)
)
}
private predicate unspecifiedTypeIsModifiableAt(Type unspecified, int indirectionIndex) {
indirectionIndex = [1 .. getIndirectionForUnspecifiedType(unspecified).getNumberOfIndirections()] and
exists(CppType cppType |
@@ -449,7 +438,7 @@ class GlobalUse extends UseImpl, TGlobalUse {
override FinalGlobalValue getNode() { result.getGlobalUse() = this }
override int getIndirection() { isGlobalUse(global, f, result, ind) }
override int getIndirection() { result = ind + 1 }
/** Gets the global variable associated with this use. */
GlobalLikeVariable getVariable() { result = global }
@@ -471,9 +460,7 @@ class GlobalUse extends UseImpl, TGlobalUse {
)
}
override SourceVariable getSourceVariable() {
sourceVariableIsGlobal(result, global, f, this.getIndirection())
}
override SourceVariable getSourceVariable() { sourceVariableIsGlobal(result, global, f, ind) }
final override Cpp::Location getLocation() { result = f.getLocation() }
@@ -514,18 +501,16 @@ class GlobalDefImpl extends DefOrUseImpl, TGlobalDefImpl {
/** Gets the global variable associated with this definition. */
override SourceVariable getSourceVariable() {
sourceVariableIsGlobal(result, global, f, this.getIndirection())
sourceVariableIsGlobal(result, global, f, indirectionIndex)
}
int getIndirection() { result = indirectionIndex }
/**
* Gets the type of this use after specifiers have been deeply stripped
* and typedefs have been resolved.
*/
Type getUnspecifiedType() { result = global.getUnspecifiedType() }
override string toString() { result = "Def of " + this.getSourceVariable() }
override string toString() { result = "GlobalDef" }
override Location getLocation() { result = f.getLocation() }
@@ -995,7 +980,7 @@ class GlobalDef extends TGlobalDef, SsaDefOrUse {
final override Location getLocation() { result = global.getLocation() }
/** Gets a textual representation of this definition. */
override string toString() { result = global.toString() }
override string toString() { result = "GlobalDef" }
/**
* Holds if this definition has index `index` in block `block`, and
@@ -1005,9 +990,6 @@ class GlobalDef extends TGlobalDef, SsaDefOrUse {
global.hasIndexInBlock(block, index, sv)
}
/** Gets the indirection index of this definition. */
int getIndirection() { result = global.getIndirection() }
/** Gets the indirection index of this definition. */
int getIndirectionIndex() { result = global.getIndirectionIndex() }

View File

@@ -228,7 +228,7 @@ private class PointerWrapperTypeIndirection extends Indirection instanceof Point
override predicate isAdditionalDereference(Instruction deref, Operand address) {
exists(CallInstruction call |
operandForFullyConvertedCall(getAUse(deref), call) and
this = call.getStaticCallTarget().getClassAndName(["operator*", "operator->", "get"]) and
this = call.getStaticCallTarget().getClassAndName("operator*") and
address = call.getThisArgumentOperand()
)
}

View File

@@ -1,6 +1,5 @@
private import cpp
import semmle.code.cpp.ir.implementation.raw.IR
private import semmle.code.cpp.internal.ExtractorVersion
private import semmle.code.cpp.ir.IRConfiguration
private import semmle.code.cpp.ir.implementation.Opcode
private import semmle.code.cpp.ir.implementation.internal.OperandTag
@@ -362,12 +361,6 @@ predicate ignoreLoad(Expr expr) {
or
expr instanceof FunctionAccess
or
// The load is duplicated from the operand.
isExtractorFrontendVersion65OrHigher() and expr instanceof ParenthesisExpr
or
// The load is duplicated from the right operand.
isExtractorFrontendVersion65OrHigher() and expr instanceof CommaExpr
or
expr.(PointerDereferenceExpr).getOperand().getFullyConverted().getType().getUnspecifiedType()
instanceof FunctionPointerType
or

View File

@@ -1,5 +1,4 @@
private import cpp
private import semmle.code.cpp.internal.ExtractorVersion
private import semmle.code.cpp.ir.implementation.IRType
private import semmle.code.cpp.ir.implementation.Opcode
private import semmle.code.cpp.ir.implementation.internal.OperandTag
@@ -650,9 +649,7 @@ class TranslatedPrefixCrementOperation extends TranslatedCrementOperation {
override PrefixCrementOperation expr;
override Instruction getResult() {
// The following distinction is needed to work around extractor limitations
// in old versions of the extractor.
if expr.isPRValueCategory() and not isExtractorFrontendVersion65OrHigher()
if expr.isPRValueCategory()
then
// If this is C, then the result of a prefix crement is a prvalue for the
// new value assigned to the operand. If this is C++, then the result is
@@ -1507,9 +1504,7 @@ class TranslatedAssignExpr extends TranslatedNonConstantExpr {
}
final override Instruction getResult() {
// The following distinction is needed to work around extractor limitations
// in old versions of the extractor.
if expr.isPRValueCategory() and not isExtractorFrontendVersion65OrHigher()
if expr.isPRValueCategory()
then
// If this is C, then the result of an assignment is a prvalue for the new
// value assigned to the left operand. If this is C++, then the result is
@@ -1647,9 +1642,7 @@ class TranslatedAssignOperation extends TranslatedNonConstantExpr {
}
final override Instruction getResult() {
// The following distinction is needed to work around extractor limitations
// in old versions of the extractor.
if expr.isPRValueCategory() and not isExtractorFrontendVersion65OrHigher()
if expr.isPRValueCategory()
then
// If this is C, then the result of an assignment is a prvalue for the new
// value assigned to the left operand. If this is C++, then the result is
@@ -2198,16 +2191,8 @@ abstract class TranslatedConditionalExpr extends TranslatedNonConstantExpr {
not this.elseIsVoid() and tag = ConditionValueFalseStoreTag()
) and
opcode instanceof Opcode::Store and
if isExtractorFrontendVersion65OrHigher()
then
not expr.hasLValueToRValueConversion() and
resultType = this.getResultType()
or
expr.hasLValueToRValueConversion() and
resultType = getTypeForPRValue(expr.getType())
else resultType = this.getResultType()
resultType = this.getResultType()
or
(not expr.hasLValueToRValueConversion() or not isExtractorFrontendVersion65OrHigher()) and
tag = ConditionValueResultLoadTag() and
opcode instanceof Opcode::Load and
resultType = this.getResultType()
@@ -2237,16 +2222,8 @@ abstract class TranslatedConditionalExpr extends TranslatedNonConstantExpr {
)
or
tag = ConditionValueResultTempAddressTag() and
if isExtractorFrontendVersion65OrHigher()
then
not expr.hasLValueToRValueConversion() and
result = this.getInstruction(ConditionValueResultLoadTag())
or
expr.hasLValueToRValueConversion() and
result = this.getParent().getChildSuccessor(this)
else result = this.getInstruction(ConditionValueResultLoadTag())
result = this.getInstruction(ConditionValueResultLoadTag())
or
(not expr.hasLValueToRValueConversion() or not isExtractorFrontendVersion65OrHigher()) and
tag = ConditionValueResultLoadTag() and
result = this.getParent().getChildSuccessor(this)
)
@@ -2275,24 +2252,18 @@ abstract class TranslatedConditionalExpr extends TranslatedNonConstantExpr {
result = this.getElse().getResult()
)
or
(not expr.hasLValueToRValueConversion() or not isExtractorFrontendVersion65OrHigher()) and
tag = ConditionValueResultLoadTag() and
operandTag instanceof AddressOperandTag and
result = this.getInstruction(ConditionValueResultTempAddressTag())
(
operandTag instanceof AddressOperandTag and
result = this.getInstruction(ConditionValueResultTempAddressTag())
)
)
}
final override predicate hasTempVariable(TempVariableTag tag, CppType type) {
not this.resultIsVoid() and
tag = ConditionValueTempVar() and
if isExtractorFrontendVersion65OrHigher()
then
not expr.hasLValueToRValueConversion() and
type = this.getResultType()
or
expr.hasLValueToRValueConversion() and
type = getTypeForPRValue(expr.getType())
else type = this.getResultType()
type = this.getResultType()
}
final override IRVariable getInstructionVariable(InstructionTag tag) {
@@ -2307,14 +2278,7 @@ abstract class TranslatedConditionalExpr extends TranslatedNonConstantExpr {
final override Instruction getResult() {
not this.resultIsVoid() and
if isExtractorFrontendVersion65OrHigher()
then
expr.hasLValueToRValueConversion() and
result = this.getInstruction(ConditionValueResultTempAddressTag())
or
not expr.hasLValueToRValueConversion() and
result = this.getInstruction(ConditionValueResultLoadTag())
else result = this.getInstruction(ConditionValueResultLoadTag())
result = this.getInstruction(ConditionValueResultLoadTag())
}
override Instruction getChildSuccessor(TranslatedElement child) {
@@ -3274,18 +3238,10 @@ predicate exprNeedsCopyIfNotLoaded(Expr expr) {
expr instanceof AssignExpr
or
expr instanceof AssignOperation and
(
not expr.isPRValueCategory() // is C++
or
isExtractorFrontendVersion65OrHigher()
)
not expr.isPRValueCategory() // is C++
or
expr instanceof PrefixCrementOperation and
(
not expr.isPRValueCategory() // is C++
or
isExtractorFrontendVersion65OrHigher()
)
not expr.isPRValueCategory() // is C++
or
// Because the load is on the `e` in `e++`.
expr instanceof PostfixCrementOperation

View File

@@ -19,7 +19,6 @@ private import implementations.Strtok
private import implementations.Strset
private import implementations.Strcrement
private import implementations.Strnextc
private import implementations.Strtol
private import implementations.StdContainer
private import implementations.StdPair
private import implementations.StdMap
@@ -35,7 +34,6 @@ private import implementations.Accept
private import implementations.Poll
private import implementations.Select
private import implementations.MySql
private import implementations.ODBC
private import implementations.SqLite3
private import implementations.PostgreSql
private import implementations.System

View File

@@ -5,7 +5,6 @@
*/
import semmle.code.cpp.models.interfaces.Allocation
import semmle.code.cpp.models.interfaces.Taint
/**
* An allocation function (such as `malloc`) that has an argument for the size
@@ -122,7 +121,7 @@ private class CallocAllocationFunction extends AllocationFunction {
* An allocation function (such as `realloc`) that has an argument for the size
* in bytes, and an argument for an existing pointer that is to be reallocated.
*/
private class ReallocAllocationFunction extends AllocationFunction, TaintFunction {
private class ReallocAllocationFunction extends AllocationFunction {
int sizeArg;
int reallocArg;
@@ -152,10 +151,6 @@ private class ReallocAllocationFunction extends AllocationFunction, TaintFunctio
override int getSizeArg() { result = sizeArg }
override int getReallocPtrArg() { result = reallocArg }
override predicate hasTaintFlow(FunctionInput input, FunctionOutput output) {
input.isParameterDeref(this.getReallocPtrArg()) and output.isReturnValueDeref()
}
}
/**

View File

@@ -49,11 +49,10 @@ private class FgetsFunction extends DataFlowFunction, TaintFunction, ArrayFuncti
}
override predicate hasRemoteFlowSource(FunctionOutput output, string description) {
(
output.isParameterDeref(0) or
output.isReturnValue() or
output.isReturnValueDeref()
) and
output.isParameterDeref(0) and
description = "string read by " + this.getName()
or
output.isReturnValue() and
description = "string read by " + this.getName()
}

View File

@@ -157,7 +157,7 @@ private class Getaddrinfo extends TaintFunction, ArrayFunction, RemoteFlowSource
override predicate hasArrayWithNullTerminator(int bufParam) { bufParam in [0, 1] }
override predicate hasRemoteFlowSource(FunctionOutput output, string description) {
output.isParameterDeref(3, 2) and
output.isParameterDeref(3) and
description = "address returned by " + this.getName()
}
}

View File

@@ -9,17 +9,18 @@ import semmle.code.cpp.models.interfaces.DataFlow
import semmle.code.cpp.models.interfaces.Alias
import semmle.code.cpp.models.interfaces.SideEffect
private class MemsetFunctionModel extends ArrayFunction, DataFlowFunction, AliasFunction,
/**
* The standard function `memset` and its assorted variants
*/
private class MemsetFunction extends ArrayFunction, DataFlowFunction, AliasFunction,
SideEffectFunction
{
MemsetFunctionModel() {
MemsetFunction() {
this.hasGlobalOrStdOrBslName("memset")
or
this.hasGlobalOrStdName("wmemset")
or
this.hasGlobalName([
bzero(), "__builtin_memset", "__builtin_memset_chk", "RtlZeroMemory", "RtlSecureZeroMemory"
])
this.hasGlobalName([bzero(), "__builtin_memset", "__builtin_memset_chk"])
}
override predicate hasArrayOutput(int bufParam) { bufParam = 0 }
@@ -59,8 +60,3 @@ private class MemsetFunctionModel extends ArrayFunction, DataFlowFunction, Alias
}
private string bzero() { result = ["bzero", "explicit_bzero"] }
/**
* The standard function `memset` and its assorted variants
*/
class MemsetFunction extends Function instanceof MemsetFunctionModel { }

View File

@@ -1,28 +0,0 @@
/**
* Provides implementation classes modeling the ODBC C/C++ API.
* See `semmle.code.cpp.models.Models` for usage information.
*/
private import semmle.code.cpp.models.interfaces.Sql
private import semmle.code.cpp.models.interfaces.FunctionInputsAndOutputs
/**
* The `SQLExecDirect`, and `SQLPrepare` from the ODBC C/C++ API:
* https://learn.microsoft.com/en-us/sql/odbc/reference/syntax/sqlexecdirect-function?view=sql-server-ver16
* https://learn.microsoft.com/en-us/sql/odbc/reference/syntax/sqlprepare-function?view=sql-server-ver16
*
* Note, `SQLExecute` is not included because it operates on a SQLHSTMT type, not a string.
* The SQLHSTMT parameter for `SQLExecute` is set through a `SQLPrepare`, which is modeled.
* The other source of input to a `SQLExecute` is via a `SQLBindParameter`, which sanitizes user input,
* and would be considered a barrier to SQL injection.
*/
private class ODBCExecutionFunction extends SqlExecutionFunction {
ODBCExecutionFunction() { this.hasGlobalName(["SQLExecDirect", "SQLPrepare"]) }
override predicate hasSqlArgument(FunctionInput input) { input.isParameterDeref(1) }
}
// NOTE: no need to define a barrier explicitly.
// `SQLBindParameter` is the typical means for sanitizing user input.
// https://learn.microsoft.com/en-us/sql/odbc/reference/syntax/sqlbindparameter-function?view=sql-server-ver16
// First a query is establisehed via `SQLPrepare`, then parameters are bound via `SQLBindParameter`, before
// the query is executed via `SQLExecute`. We are not modeling SQLExecute, so we do not need to model SQLBindParameter.

View File

@@ -147,32 +147,19 @@ private class SnprintfImpl extends Snprintf {
/**
* The Microsoft `StringCchPrintf` function and variants.
* See: https://learn.microsoft.com/en-us/windows/win32/api/strsafe/
* and
* https://learn.microsoft.com/en-us/previous-versions/windows/embedded/ms860435(v=msdn.10)
*/
private class StringCchPrintf extends FormattingFunction {
StringCchPrintf() {
this instanceof TopLevelFunction and
exists(string baseName |
baseName in [
"StringCchPrintf", //StringCchPrintf(pszDest, cchDest, pszFormat, ...)
"StringCchPrintfEx", //StringCchPrintfEx(pszDest,cchDest, ppszDestEnd, pcchRemaining, dwFlags, pszFormat, ...)
"StringCchPrintf_l", //StringCchPrintf_l(pszDest, cbDest, pszFormat, locale, ...)
"StringCchPrintf_lEx", //StringCchPrintf_lEx(pszDest, cchDest, ppszDestEnd, pcchRemaining, dwFlags, pszFormat, locale, ...)
"StringCbPrintf", //StringCbPrintf(pszDest, cbDest, pszFormat, ...)
"StringCbPrintfEx", //StringCbPrintfEx(pszDest, cbDest, ppszDestEnd, pcbRemaining, dwFlags, pszFormat, ...)
"StringCbPrintf_l", //StringCbPrintf_l(pszDest, cbDest, pszFormat, locale, ...)
"StringCbPrintf_lEx" //StringCbPrintf_lEx(pszDest, cbDest, ppszDestEnd, pcbRemaining, dwFlags, pszFormat, locale, ...)
]
|
this.hasGlobalName(baseName + ["", "A", "W"])
) and
this.hasGlobalName([
"StringCchPrintf", "StringCchPrintfEx", "StringCchPrintf_l", "StringCchPrintf_lEx",
"StringCbPrintf", "StringCbPrintfEx", "StringCbPrintf_l", "StringCbPrintf_lEx"
]) and
not exists(this.getDefinition().getFile().getRelativePath())
}
override int getFormatParameterIndex() {
if this.getName().matches("%Ex" + ["", "A", "W"]) then result = 5 else result = 2
if this.getName().matches("%Ex") then result = 5 else result = 2
}
override int getOutputParameterIndex(boolean isStream) { result = 0 and isStream = false }

View File

@@ -13,7 +13,7 @@ private class PureStrFunction extends AliasFunction, ArrayFunction, TaintFunctio
PureStrFunction() {
this.hasGlobalOrStdOrBslName([
atoi(), "strcasestr", "strchnul", "strchr", "strchrnul", "strstr", "strpbrk", "strrchr",
"strspn", strrev(), strcmp(), strlwr(), strupr()
"strspn", strtol(), strrev(), strcmp(), strlwr(), strupr()
])
}
@@ -70,6 +70,8 @@ private class PureStrFunction extends AliasFunction, ArrayFunction, TaintFunctio
private string atoi() { result = ["atof", "atoi", "atol", "atoll"] }
private string strtol() { result = ["strtod", "strtof", "strtol", "strtoll", "strtoq", "strtoul"] }
private string strlwr() {
result = ["_strlwr", "_wcslwr", "_mbslwr", "_strlwr_l", "_wcslwr_l", "_mbslwr_l"]
}

View File

@@ -58,7 +58,7 @@ private class Send extends AliasFunction, ArrayFunction, SideEffectFunction, Rem
override ParameterIndex getParameterSizeIndex(ParameterIndex i) { i = 1 and result = 2 }
override predicate hasRemoteFlowSink(FunctionInput input, string description) {
input.isParameterDeref(1, 1) and description = "buffer sent by " + this.getName()
input.isParameterDeref(1) and description = "buffer sent by " + this.getName()
}
override predicate hasSocketInput(FunctionInput input) { input.isParameter(0) }

View File

@@ -10,8 +10,6 @@ import semmle.code.cpp.models.interfaces.SideEffect
/**
* The standard function `strcat` and its wide, sized, and Microsoft variants.
*
* Does not include `strlcat`, which is covered by `StrlcatFunction`
*/
class StrcatFunction extends TaintFunction, DataFlowFunction, ArrayFunction, SideEffectFunction {
StrcatFunction() {
@@ -92,64 +90,3 @@ class StrcatFunction extends TaintFunction, DataFlowFunction, ArrayFunction, Sid
buffer = true
}
}
/**
* The `strlcat` function.
*/
class StrlcatFunction extends TaintFunction, ArrayFunction, SideEffectFunction {
StrlcatFunction() {
this.hasGlobalName("strlcat") // strlcat(dst, src, dst_size)
}
/**
* Gets the index of the parameter that is the size of the copy (in characters).
*/
int getParamSize() { result = 2 }
/**
* Gets the index of the parameter that is the source of the copy.
*/
int getParamSrc() { result = 1 }
/**
* Gets the index of the parameter that is the destination to be appended to.
*/
int getParamDest() { result = 0 }
override predicate hasTaintFlow(FunctionInput input, FunctionOutput output) {
(
input.isParameter(2)
or
input.isParameterDeref(0)
or
input.isParameterDeref(1)
) and
output.isParameterDeref(0)
}
override predicate hasArrayInput(int param) {
param = 0 or
param = 1
}
override predicate hasArrayOutput(int param) { param = 0 }
override predicate hasArrayWithNullTerminator(int param) { param = 1 }
override predicate hasArrayWithUnknownSize(int param) { param = 0 }
override predicate hasOnlySpecificReadSideEffects() { any() }
override predicate hasOnlySpecificWriteSideEffects() { any() }
override predicate hasSpecificWriteSideEffect(ParameterIndex i, boolean buffer, boolean mustWrite) {
i = 0 and
buffer = true and
mustWrite = false
}
override predicate hasSpecificReadSideEffect(ParameterIndex i, boolean buffer) {
(i = 0 or i = 1) and
buffer = true
}
}

View File

@@ -32,8 +32,7 @@ class StrcpyFunction extends ArrayFunction, DataFlowFunction, TaintFunction, Sid
"wcsxfrm_l", // _strxfrm_l(dest, src, max_amount, locale)
"_mbsnbcpy", // _mbsnbcpy(dest, src, max_amount)
"stpcpy", // stpcpy(dest, src)
"stpncpy", // stpncpy(dest, src, max_amount)
"strlcpy" // strlcpy(dst, src, dst_size)
"stpncpy" // stpcpy(dest, src, max_amount)
])
or
(
@@ -54,11 +53,6 @@ class StrcpyFunction extends ArrayFunction, DataFlowFunction, TaintFunction, Sid
*/
private predicate isSVariant() { this.getName().matches("%\\_s") }
/**
* Holds if the function returns the total length the string would have had if the size was unlimited.
*/
private predicate returnsTotalLength() { this.getName() = "strlcpy" }
/**
* Gets the index of the parameter that is the maximum size of the copy (in characters).
*/
@@ -66,7 +60,7 @@ class StrcpyFunction extends ArrayFunction, DataFlowFunction, TaintFunction, Sid
if this.isSVariant()
then result = 1
else (
this.getName().matches(["%ncpy%", "%nbcpy%", "%xfrm%", "strlcpy"]) and
this.getName().matches(["%ncpy%", "%nbcpy%", "%xfrm%"]) and
result = 2
)
}
@@ -106,7 +100,6 @@ class StrcpyFunction extends ArrayFunction, DataFlowFunction, TaintFunction, Sid
input.isParameterDeref(this.getParamSrc()) and
output.isReturnValueDeref()
or
not this.returnsTotalLength() and
input.isParameter(this.getParamDest()) and
output.isReturnValue()
}
@@ -117,9 +110,8 @@ class StrcpyFunction extends ArrayFunction, DataFlowFunction, TaintFunction, Sid
exists(this.getParamSize()) and
input.isParameterDeref(this.getParamSrc()) and
(
output.isParameterDeref(this.getParamDest())
or
not this.returnsTotalLength() and output.isReturnValueDeref()
output.isParameterDeref(this.getParamDest()) or
output.isReturnValueDeref()
)
}

View File

@@ -32,8 +32,6 @@ private class Strtok extends ArrayFunction, AliasFunction, TaintFunction, SideEf
override predicate hasTaintFlow(FunctionInput input, FunctionOutput output) {
input.isParameter(0) and output.isReturnValue()
or
input.isParameterDeref(0) and output.isReturnValueDeref()
}
override predicate hasOnlySpecificReadSideEffects() { none() }

View File

@@ -1,54 +0,0 @@
import semmle.code.cpp.models.interfaces.ArrayFunction
import semmle.code.cpp.models.interfaces.Taint
import semmle.code.cpp.models.interfaces.Alias
import semmle.code.cpp.models.interfaces.SideEffect
private string strtol() { result = ["strtod", "strtof", "strtol", "strtoll", "strtoq", "strtoul"] }
/**
* The standard function `strtol` and its assorted variants
*/
private class Strtol extends AliasFunction, ArrayFunction, TaintFunction, SideEffectFunction {
Strtol() { this.hasGlobalOrStdOrBslName(strtol()) }
override predicate hasArrayInput(int bufParam) {
// All the functions given by `strtol()` takes a `const char*` input as the first parameter
bufParam = 0
}
override predicate hasArrayWithNullTerminator(int bufParam) { bufParam = 0 }
override predicate hasTaintFlow(FunctionInput input, FunctionOutput output) {
(
input.isParameter(0)
or
input.isParameterDeref(0)
) and
output.isReturnValue()
or
input.isParameter(0) and
output.isParameterDeref(1)
}
override predicate parameterNeverEscapes(int i) {
// Parameter 0 does escape into parameter 1.
i = 1
}
override predicate parameterEscapesOnlyViaReturn(int i) { none() }
override predicate parameterIsAlwaysReturned(int i) { none() }
override predicate hasOnlySpecificReadSideEffects() { any() }
override predicate hasOnlySpecificWriteSideEffects() { any() }
override predicate hasSpecificReadSideEffect(ParameterIndex i, boolean buffer) {
i = 0 and
buffer = true
}
override predicate hasSpecificWriteSideEffect(ParameterIndex i, boolean buffer, boolean mustWrite) {
i = 1 and buffer = false and mustWrite = false
}
}

View File

@@ -8,7 +8,7 @@ import semmle.code.cpp.Parameter
private newtype TFunctionInput =
TInParameter(ParameterIndex i) or
TInParameterDeref(ParameterIndex i, int indirectionIndex) { indirectionIndex = [1, 2] } or
TInParameterDeref(ParameterIndex i) or
TInQualifierObject() or
TInQualifierAddress() or
TInReturnValueDeref()
@@ -245,18 +245,15 @@ class InParameter extends FunctionInput, TInParameter {
*/
class InParameterDeref extends FunctionInput, TInParameterDeref {
ParameterIndex index;
int indirectionIndex;
InParameterDeref() { this = TInParameterDeref(index, indirectionIndex) }
InParameterDeref() { this = TInParameterDeref(index) }
override string toString() { result = "InParameterDeref " + index.toString() }
/** Gets the zero-based index of the parameter. */
ParameterIndex getIndex() { result = index }
override predicate isParameterDeref(ParameterIndex i, int indirection) {
i = index and indirectionIndex = indirection
}
override predicate isParameterDeref(ParameterIndex i) { i = index }
}
/**
@@ -324,10 +321,10 @@ class InReturnValueDeref extends FunctionInput, TInReturnValueDeref {
}
private newtype TFunctionOutput =
TOutParameterDeref(ParameterIndex i, int indirectionIndex) { indirectionIndex = [1, 2] } or
TOutParameterDeref(ParameterIndex i) or
TOutQualifierObject() or
TOutReturnValue() or
TOutReturnValueDeref(int indirections) { indirections = [1, 2] }
TOutReturnValueDeref()
/**
* An output from a function. This can be:
@@ -501,16 +498,17 @@ class FunctionOutput extends TFunctionOutput {
*/
class OutParameterDeref extends FunctionOutput, TOutParameterDeref {
ParameterIndex index;
int indirectionIndex;
OutParameterDeref() { this = TOutParameterDeref(index, indirectionIndex) }
OutParameterDeref() { this = TOutParameterDeref(index) }
override string toString() { result = "OutParameterDeref " + index.toString() }
ParameterIndex getIndex() { result = index }
override predicate isParameterDeref(ParameterIndex i) { i = index }
override predicate isParameterDeref(ParameterIndex i, int ind) {
i = index and ind = indirectionIndex
this.isParameterDeref(i) and ind = 1
}
}
@@ -574,8 +572,4 @@ class OutReturnValueDeref extends FunctionOutput, TOutReturnValueDeref {
override string toString() { result = "OutReturnValueDeref" }
override predicate isReturnValueDeref() { any() }
override predicate isReturnValueDeref(int indirectionIndex) {
this = TOutReturnValueDeref(indirectionIndex)
}
}

View File

@@ -17,7 +17,9 @@ private import semmle.code.cpp.valuenumbering.GlobalValueNumbering
* `upper` is true, and can be traced back to a guard represented by `reason`.
*/
predicate bounded(Expr e, Bound b, float delta, boolean upper, Reason reason) {
exists(SemanticExprConfig::Expr semExpr | semExpr.getUnconvertedResultExpression() = e |
exists(SemanticExprConfig::Expr semExpr |
semExpr.getUnconverted().getUnconvertedResultExpression() = e
|
semBounded(semExpr, b, delta, upper, reason)
)
}
@@ -28,7 +30,9 @@ predicate bounded(Expr e, Bound b, float delta, boolean upper, Reason reason) {
* The `Expr` may be a conversion.
*/
predicate convertedBounded(Expr e, Bound b, float delta, boolean upper, Reason reason) {
exists(SemanticExprConfig::Expr semExpr | semExpr.getConvertedResultExpression() = e |
exists(SemanticExprConfig::Expr semExpr |
semExpr.getConverted().getConvertedResultExpression() = e
|
semBounded(semExpr, b, delta, upper, reason)
)
}

View File

@@ -100,7 +100,7 @@ predicate exprMightOverflowNegatively(Expr expr) {
lowerBound(expr) < exprMinVal(expr)
or
exists(SemanticExprConfig::Expr semExpr |
semExpr.getAst() = expr and
semExpr.getUnconverted().getAst() = expr and
ConstantStage::potentiallyOverflowingExpr(false, semExpr) and
not ConstantStage::initialBounded(semExpr, _, _, false, _, _, _)
)
@@ -126,7 +126,7 @@ predicate exprMightOverflowPositively(Expr expr) {
upperBound(expr) > exprMaxVal(expr)
or
exists(SemanticExprConfig::Expr semExpr |
semExpr.getAst() = expr and
semExpr.getUnconverted().getAst() = expr and
ConstantStage::potentiallyOverflowingExpr(true, semExpr) and
not ConstantStage::initialBounded(semExpr, _, _, true, _, _, _)
)

View File

@@ -12,6 +12,9 @@ class SemBasicBlock extends Specific::BasicBlock {
/** Holds if this block (transitively) dominates `otherblock`. */
final predicate bbDominates(SemBasicBlock otherBlock) { Specific::bbDominates(this, otherBlock) }
/** Holds if this block has dominance information. */
final predicate hasDominanceInformation() { Specific::hasDominanceInformation(this) }
/** Gets an expression that is evaluated in this basic block. */
final SemExpr getAnExpr() { result.getBasicBlock() = this }

View File

@@ -4,7 +4,6 @@
private import Semantic
private import SemanticExprSpecific::SemanticExprConfig as Specific
private import SemanticType
/**
* An language-neutral expression.
@@ -242,21 +241,8 @@ class SemConvertExpr extends SemUnaryExpr {
SemConvertExpr() { opcode instanceof Opcode::Convert }
}
private import semmle.code.cpp.ir.IR as IR
/** A conversion instruction which is guaranteed to not overflow. */
private class SafeConversion extends IR::ConvertInstruction {
SafeConversion() {
exists(SemType tFrom, SemType tTo |
tFrom = getSemanticType(super.getUnary().getResultIRType()) and
tTo = getSemanticType(super.getResultIRType()) and
conversionCannotOverflow(tFrom, tTo)
)
}
}
class SemCopyValueExpr extends SemUnaryExpr {
SemCopyValueExpr() { opcode instanceof Opcode::CopyValue or this instanceof SafeConversion }
SemCopyValueExpr() { opcode instanceof Opcode::CopyValue }
}
class SemNegateExpr extends SemUnaryExpr {

View File

@@ -12,10 +12,87 @@ private import semmle.code.cpp.ir.ValueNumbering
module SemanticExprConfig {
class Location = Cpp::Location;
/** A `ConvertInstruction` or a `CopyValueInstruction`. */
private class Conversion extends IR::UnaryInstruction {
Conversion() {
this instanceof IR::CopyValueInstruction
or
this instanceof IR::ConvertInstruction
}
/** Holds if this instruction converts a value of type `tFrom` to a value of type `tTo`. */
predicate converts(SemType tFrom, SemType tTo) {
tFrom = getSemanticType(this.getUnary().getResultIRType()) and
tTo = getSemanticType(this.getResultIRType())
}
}
/**
* Gets a conversion-like instruction that consumes `op`, and
* which is guaranteed to not overflow.
*/
private IR::Instruction safeConversion(IR::Operand op) {
exists(Conversion conv, SemType tFrom, SemType tTo |
conv.converts(tFrom, tTo) and
conversionCannotOverflow(tFrom, tTo) and
conv.getUnaryOperand() = op and
result = conv
)
}
/** Holds if `i1 = i2` or if `i2` is a safe conversion that consumes `i1`. */
private predicate idOrSafeConversion(IR::Instruction i1, IR::Instruction i2) {
not i1.getResultIRType() instanceof IR::IRVoidType and
(
i1 = i2
or
i2 = safeConversion(i1.getAUse()) and
i1.getBlock() = i2.getBlock()
)
}
module Equiv = QlBuiltins::EquivalenceRelation<IR::Instruction, idOrSafeConversion/2>;
/**
* The expressions on which we perform range analysis.
*/
class Expr = IR::Instruction;
class Expr extends Equiv::EquivalenceClass {
/** Gets the n'th instruction in this equivalence class. */
private IR::Instruction getInstruction(int n) {
result =
rank[n + 1](IR::Instruction instr, int i, IR::IRBlock block |
this = Equiv::getEquivalenceClass(instr) and block.getInstruction(i) = instr
|
instr order by i
)
}
/** Gets a textual representation of this element. */
string toString() { result = this.getUnconverted().toString() }
/** Gets the basic block of this expression. */
IR::IRBlock getBlock() { result = this.getUnconverted().getBlock() }
/** Gets the unconverted instruction associated with this expression. */
IR::Instruction getUnconverted() { result = this.getInstruction(0) }
/**
* Gets the final instruction associated with this expression. This
* represents the result after applying all the safe conversions.
*/
IR::Instruction getConverted() {
exists(int n |
result = this.getInstruction(n) and
not exists(this.getInstruction(n + 1))
)
}
/** Gets the type of the result produced by this instruction. */
IR::IRType getResultIRType() { result = this.getConverted().getResultIRType() }
/** Gets the location of the source code for this expression. */
Location getLocation() { result = this.getUnconverted().getLocation() }
}
SemBasicBlock getExprBasicBlock(Expr e) { result = getSemanticBasicBlock(e.getBlock()) }
@@ -62,12 +139,12 @@ module SemanticExprConfig {
predicate stringLiteral(Expr expr, SemType type, string value) {
anyConstantExpr(expr, type, value) and
expr instanceof IR::StringConstantInstruction
expr.getUnconverted() instanceof IR::StringConstantInstruction
}
predicate binaryExpr(Expr expr, Opcode opcode, SemType type, Expr leftOperand, Expr rightOperand) {
exists(IR::BinaryInstruction instr |
instr = expr and
instr = expr.getUnconverted() and
type = getSemanticType(instr.getResultIRType()) and
leftOperand = getSemanticExpr(instr.getLeft()) and
rightOperand = getSemanticExpr(instr.getRight()) and
@@ -77,14 +154,14 @@ module SemanticExprConfig {
}
predicate unaryExpr(Expr expr, Opcode opcode, SemType type, Expr operand) {
exists(IR::UnaryInstruction instr | instr = expr |
exists(IR::UnaryInstruction instr | instr = expr.getUnconverted() |
type = getSemanticType(instr.getResultIRType()) and
operand = getSemanticExpr(instr.getUnary()) and
// REVIEW: Merge the two operand types.
opcode.toString() = instr.getOpcode().toString()
)
or
exists(IR::StoreInstruction instr | instr = expr |
exists(IR::StoreInstruction instr | instr = expr.getUnconverted() |
type = getSemanticType(instr.getResultIRType()) and
operand = getSemanticExpr(instr.getSourceValue()) and
opcode instanceof Opcode::Store
@@ -93,13 +170,13 @@ module SemanticExprConfig {
predicate nullaryExpr(Expr expr, Opcode opcode, SemType type) {
exists(IR::LoadInstruction load |
load = expr and
load = expr.getUnconverted() and
type = getSemanticType(load.getResultIRType()) and
opcode instanceof Opcode::Load
)
or
exists(IR::InitializeParameterInstruction init |
init = expr and
init = expr.getUnconverted() and
type = getSemanticType(init.getResultIRType()) and
opcode instanceof Opcode::InitializeParameter
)
@@ -122,6 +199,8 @@ module SemanticExprConfig {
dominator.dominates(dominated)
}
predicate hasDominanceInformation(BasicBlock block) { any() }
private predicate id(Cpp::Locatable x, Cpp::Locatable y) { x = y }
private predicate idOf(Cpp::Locatable x, int y) = equivalenceRelation(id/2)(x, y)
@@ -130,7 +209,17 @@ module SemanticExprConfig {
newtype TSsaVariable =
TSsaInstruction(IR::Instruction instr) { instr.hasMemoryResult() } or
TSsaOperand(IR::PhiInputOperand op) { op.isDefinitionInexact() }
TSsaOperand(IR::Operand op) { op.isDefinitionInexact() } or
TSsaPointerArithmeticGuard(ValueNumber instr) {
exists(Guard g, IR::Operand use |
use = instr.getAUse() and use.getIRType() instanceof IR::IRAddressType
|
g.comparesLt(use, _, _, _, _) or
g.comparesLt(_, use, _, _, _) or
g.comparesEq(use, _, _, _, _) or
g.comparesEq(_, use, _, _, _)
)
}
class SsaVariable extends TSsaVariable {
string toString() { none() }
@@ -139,7 +228,9 @@ module SemanticExprConfig {
IR::Instruction asInstruction() { none() }
IR::PhiInputOperand asOperand() { none() }
ValueNumber asPointerArithGuard() { none() }
IR::Operand asOperand() { none() }
}
class SsaInstructionVariable extends SsaVariable, TSsaInstruction {
@@ -154,8 +245,20 @@ module SemanticExprConfig {
final override IR::Instruction asInstruction() { result = instr }
}
class SsaPointerArithmeticGuard extends SsaVariable, TSsaPointerArithmeticGuard {
ValueNumber vn;
SsaPointerArithmeticGuard() { this = TSsaPointerArithmeticGuard(vn) }
final override string toString() { result = vn.toString() }
final override Location getLocation() { result = vn.getLocation() }
final override ValueNumber asPointerArithGuard() { result = vn }
}
class SsaOperand extends SsaVariable, TSsaOperand {
IR::PhiInputOperand op;
IR::Operand op;
SsaOperand() { this = TSsaOperand(op) }
@@ -163,7 +266,7 @@ module SemanticExprConfig {
final override Location getLocation() { result = op.getLocation() }
final override IR::PhiInputOperand asOperand() { result = op }
final override IR::Operand asOperand() { result = op }
}
predicate explicitUpdate(SsaVariable v, Expr sourceExpr) {
@@ -186,29 +289,97 @@ module SemanticExprConfig {
)
}
Expr getAUse(SsaVariable v) { result.(IR::LoadInstruction).getSourceValue() = v.asInstruction() }
Expr getAUse(SsaVariable v) {
result.getUnconverted().(IR::LoadInstruction).getSourceValue() = v.asInstruction()
or
result.getUnconverted() = v.asPointerArithGuard().getAnInstruction()
}
SemType getSsaVariableType(SsaVariable v) {
result = getSemanticType(v.asInstruction().getResultIRType())
or
result = getSemanticType(v.asOperand().getUse().getResultIRType())
}
BasicBlock getSsaVariableBasicBlock(SsaVariable v) {
result = v.asInstruction().getBlock()
or
result = v.asOperand().getAnyDef().getBlock()
result = v.asOperand().getUse().getBlock()
}
/** Holds if `inp` is an input to the phi node along the edge originating in `bb`. */
predicate phiInputFromBlock(SsaVariable phi, SsaVariable inp, BasicBlock bb) {
private newtype TReadPosition =
TReadPositionBlock(IR::IRBlock block) or
TReadPositionPhiInputEdge(IR::IRBlock pred, IR::IRBlock succ) {
exists(IR::PhiInputOperand input |
pred = input.getPredecessorBlock() and
succ = input.getUse().getBlock()
)
}
class SsaReadPosition extends TReadPosition {
string toString() { none() }
Location getLocation() { none() }
predicate hasRead(SsaVariable v) { none() }
}
private class SsaReadPositionBlock extends SsaReadPosition, TReadPositionBlock {
IR::IRBlock block;
SsaReadPositionBlock() { this = TReadPositionBlock(block) }
final override string toString() { result = block.toString() }
final override Location getLocation() { result = block.getLocation() }
final override predicate hasRead(SsaVariable v) {
exists(IR::Operand operand |
operand.getDef() = v.asInstruction() or
operand.getDef() = v.asPointerArithGuard().getAnInstruction()
|
not operand instanceof IR::PhiInputOperand and
operand.getUse().getBlock() = block
)
}
}
private class SsaReadPositionPhiInputEdge extends SsaReadPosition, TReadPositionPhiInputEdge {
IR::IRBlock pred;
IR::IRBlock succ;
SsaReadPositionPhiInputEdge() { this = TReadPositionPhiInputEdge(pred, succ) }
final override string toString() { result = pred.toString() + "->" + succ.toString() }
final override Location getLocation() { result = succ.getLocation() }
final override predicate hasRead(SsaVariable v) {
exists(IR::PhiInputOperand operand |
operand.getDef() = v.asInstruction() or
operand.getDef() = v.asPointerArithGuard().getAnInstruction()
|
operand.getPredecessorBlock() = pred and
operand.getUse().getBlock() = succ
)
}
}
predicate hasReadOfSsaVariable(SsaReadPosition pos, SsaVariable v) { pos.hasRead(v) }
predicate readBlock(SsaReadPosition pos, BasicBlock block) { pos = TReadPositionBlock(block) }
predicate phiInputEdge(SsaReadPosition pos, BasicBlock origBlock, BasicBlock phiBlock) {
pos = TReadPositionPhiInputEdge(origBlock, phiBlock)
}
predicate phiInput(SsaReadPosition pos, SsaVariable phi, SsaVariable input) {
exists(IR::PhiInputOperand operand |
bb = operand.getPredecessorBlock() and
pos = TReadPositionPhiInputEdge(operand.getPredecessorBlock(), operand.getUse().getBlock())
|
phi.asInstruction() = operand.getUse() and
(
inp.asInstruction() = operand.getDef()
input.asInstruction() = operand.getDef()
or
inp.asOperand() = operand
input.asOperand() = operand
)
)
}
@@ -262,7 +433,7 @@ module SemanticExprConfig {
}
/** Gets the expression associated with `instr`. */
SemExpr getSemanticExpr(IR::Instruction instr) { result = instr }
SemExpr getSemanticExpr(IR::Instruction instr) { result = Equiv::getEquivalenceClass(instr) }
}
predicate getSemanticExpr = SemanticExprConfig::getSemanticExpr/1;

View File

@@ -35,4 +35,32 @@ predicate semImplies_v2(SemGuard g1, boolean b1, SemGuard g2, boolean b2) {
Specific::implies_v2(g1, b1, g2, b2)
}
/**
* Holds if `guard` directly controls the position `controlled` with the
* value `testIsTrue`.
*/
pragma[nomagic]
predicate semGuardDirectlyControlsSsaRead(
SemGuard guard, SemSsaReadPosition controlled, boolean testIsTrue
) {
guard.directlyControls(controlled.(SemSsaReadPositionBlock).getBlock(), testIsTrue)
or
exists(SemSsaReadPositionPhiInputEdge controlledEdge | controlledEdge = controlled |
guard.directlyControls(controlledEdge.getOrigBlock(), testIsTrue) or
guard.hasBranchEdge(controlledEdge.getOrigBlock(), controlledEdge.getPhiBlock(), testIsTrue)
)
}
/**
* Holds if `guard` controls the position `controlled` with the value `testIsTrue`.
*/
predicate semGuardControlsSsaRead(SemGuard guard, SemSsaReadPosition controlled, boolean testIsTrue) {
semGuardDirectlyControlsSsaRead(guard, controlled, testIsTrue)
or
exists(SemGuard guard0, boolean testIsTrue0 |
semImplies_v2(guard0, testIsTrue0, guard, testIsTrue) and
semGuardControlsSsaRead(guard0, controlled, testIsTrue0)
)
}
SemGuard semGetComparisonGuard(SemRelationalExpr e) { result = Specific::comparisonGuard(e) }

View File

@@ -8,18 +8,6 @@ class SemLocation instanceof Location {
*/
string toString() { result = super.toString() }
/** Gets the 1-based line number (inclusive) where this location starts. */
int getStartLine() { result = super.getStartLine() }
/** Gets the 1-based column number (inclusive) where this location starts. */
int getStartColumn() { result = super.getStartColumn() }
/** Gets the 1-based line number (inclusive) where this location ends. */
int getEndLine() { result = super.getEndLine() }
/** Gets the 1-based column number (inclusive) where this location ends. */
int getEndColumn() { result = super.getEndColumn() }
/**
* Holds if this element is at the specified location.
* The location spans column `startcolumn` of line `startline` to

View File

@@ -22,15 +22,75 @@ class SemSsaExplicitUpdate extends SemSsaVariable {
SemSsaExplicitUpdate() { Specific::explicitUpdate(this, sourceExpr) }
final SemExpr getDefiningExpr() { result = sourceExpr }
final SemExpr getSourceExpr() { result = sourceExpr }
}
class SemSsaPhiNode extends SemSsaVariable {
SemSsaPhiNode() { Specific::phi(this) }
final SemSsaVariable getAPhiInput() { result = Specific::getAPhiInput(this) }
final predicate hasInputFromBlock(SemSsaVariable inp, SemBasicBlock bb) {
Specific::phiInputFromBlock(this, inp, bb)
}
}
class SemSsaReadPosition instanceof Specific::SsaReadPosition {
final string toString() { result = super.toString() }
final Specific::Location getLocation() { result = super.getLocation() }
final predicate hasReadOfVar(SemSsaVariable var) { Specific::hasReadOfSsaVariable(this, var) }
}
class SemSsaReadPositionPhiInputEdge extends SemSsaReadPosition {
SemBasicBlock origBlock;
SemBasicBlock phiBlock;
SemSsaReadPositionPhiInputEdge() { Specific::phiInputEdge(this, origBlock, phiBlock) }
predicate phiInput(SemSsaPhiNode phi, SemSsaVariable inp) { Specific::phiInput(this, phi, inp) }
SemBasicBlock getOrigBlock() { result = origBlock }
SemBasicBlock getPhiBlock() { result = phiBlock }
}
class SemSsaReadPositionBlock extends SemSsaReadPosition {
SemBasicBlock block;
SemSsaReadPositionBlock() { Specific::readBlock(this, block) }
SemBasicBlock getBlock() { result = block }
SemExpr getAnExpr() { result = this.getBlock().getAnExpr() }
}
/**
* Holds if `inp` is an input to `phi` along a back edge.
*/
predicate semBackEdge(SemSsaPhiNode phi, SemSsaVariable inp, SemSsaReadPositionPhiInputEdge edge) {
edge.phiInput(phi, inp) and
// Conservatively assume that every edge is a back edge if we don't have dominance information.
(
phi.getBasicBlock().bbDominates(edge.getOrigBlock()) or
irreducibleSccEdge(edge.getOrigBlock(), phi.getBasicBlock()) or
not edge.getOrigBlock().hasDominanceInformation()
)
}
/**
* Holds if the edge from b1 to b2 is part of a multiple-entry cycle in an irreducible control flow
* graph.
*
* An ireducible control flow graph is one where the usual dominance-based back edge detection does
* not work, because there is a cycle with multiple entry points, meaning there are
* mutually-reachable basic blocks where neither dominates the other. For such a graph, we first
* remove all detectable back-edges using the normal condition that the predecessor block is
* dominated by the successor block, then mark all edges in a cycle in the resulting graph as back
* edges.
*/
private predicate irreducibleSccEdge(SemBasicBlock b1, SemBasicBlock b2) {
trimmedEdge(b1, b2) and trimmedEdge+(b2, b1)
}
private predicate trimmedEdge(SemBasicBlock pred, SemBasicBlock succ) {
pred.getASuccessor() = succ and
not succ.bbDominates(pred)
}

View File

@@ -14,7 +14,7 @@ private predicate constantIntegerExpr(SemExpr e, int val) {
// Copy of another constant
exists(SemSsaExplicitUpdate v, SemExpr src |
e = v.getAUse() and
src = v.getDefiningExpr() and
src = v.getSourceExpr() and
constantIntegerExpr(src, val)
)
or

View File

@@ -1,7 +1,5 @@
private import RangeAnalysisStage
private import RangeAnalysisImpl
private import codeql.rangeanalysis.RangeAnalysis
private import semmle.code.cpp.rangeanalysis.new.internal.semantic.SemanticExpr
private import semmle.code.cpp.rangeanalysis.new.internal.semantic.SemanticType
module FloatDelta implements DeltaSig {
class Delta = float;
@@ -22,7 +20,7 @@ module FloatDelta implements DeltaSig {
Delta fromFloat(float f) { result = f }
}
module FloatOverflow implements OverflowSig<Sem, FloatDelta> {
module FloatOverflow implements OverflowSig<FloatDelta> {
predicate semExprDoesNotOverflow(boolean positively, SemExpr expr) {
exists(float lb, float ub, float delta |
typeBounds(expr.getSemType(), lb, ub) and

View File

@@ -0,0 +1,29 @@
private import RangeAnalysisStage
module IntDelta implements DeltaSig {
class Delta = int;
bindingset[d]
bindingset[result]
float toFloat(Delta d) { result = d }
bindingset[d]
bindingset[result]
int toInt(Delta d) { result = d }
bindingset[n]
bindingset[result]
Delta fromInt(int n) { result = n }
bindingset[f]
Delta fromFloat(float f) {
result =
min(float diff, float res |
diff = (res - f) and res = f.ceil()
or
diff = (f - res) and res = f.floor()
|
res order by diff
)
}
}

View File

@@ -0,0 +1,326 @@
/**
* Provides inferences of the form: `e` equals `b + v` modulo `m` where `e` is
* an expression, `b` is a `Bound` (typically zero or the value of an SSA
* variable), and `v` is an integer in the range `[0 .. m-1]`.
*/
/*
* The main recursion has base cases in both `ssaModulus` (for guarded reads) and `semExprModulus`
* (for constant values). The most interesting recursive case is `phiModulusRankStep`, which
* handles phi inputs.
*/
private import ModulusAnalysisSpecific::Private
private import semmle.code.cpp.rangeanalysis.new.internal.semantic.Semantic
private import ConstantAnalysis
private import RangeUtils
private import RangeAnalysisStage
module ModulusAnalysis<DeltaSig D, BoundSig<D> Bounds, UtilSig<D> U> {
pragma[nomagic]
private predicate valueFlowStepSsaEqFlowCond(
SemSsaReadPosition pos, SemSsaVariable v, SemExpr e, int delta
) {
exists(SemGuard guard, boolean testIsTrue |
guard = U::semEqFlowCond(v, e, D::fromInt(delta), true, testIsTrue) and
semGuardDirectlyControlsSsaRead(guard, pos, testIsTrue)
)
}
/**
* Holds if `e + delta` equals `v` at `pos`.
*/
pragma[nomagic]
private predicate valueFlowStepSsa(SemSsaVariable v, SemSsaReadPosition pos, SemExpr e, int delta) {
U::semSsaUpdateStep(v, e, D::fromInt(delta)) and pos.hasReadOfVar(v)
or
pos.hasReadOfVar(v) and
valueFlowStepSsaEqFlowCond(pos, v, e, delta)
}
/**
* Holds if `add` is the addition of `larg` and `rarg`, neither of which are
* `ConstantIntegerExpr`s.
*/
private predicate nonConstAddition(SemExpr add, SemExpr larg, SemExpr rarg) {
exists(SemAddExpr a | a = add |
larg = a.getLeftOperand() and
rarg = a.getRightOperand()
) and
not larg instanceof SemConstantIntegerExpr and
not rarg instanceof SemConstantIntegerExpr
}
/**
* Holds if `sub` is the subtraction of `larg` and `rarg`, where `rarg` is not
* a `ConstantIntegerExpr`.
*/
private predicate nonConstSubtraction(SemExpr sub, SemExpr larg, SemExpr rarg) {
exists(SemSubExpr s | s = sub |
larg = s.getLeftOperand() and
rarg = s.getRightOperand()
) and
not rarg instanceof SemConstantIntegerExpr
}
/** Gets an expression that is the remainder modulo `mod` of `arg`. */
private SemExpr modExpr(SemExpr arg, int mod) {
exists(SemRemExpr rem |
result = rem and
arg = rem.getLeftOperand() and
rem.getRightOperand().(SemConstantIntegerExpr).getIntValue() = mod and
mod >= 2
)
or
exists(SemConstantIntegerExpr c |
mod = 2.pow([1 .. 30]) and
c.getIntValue() = mod - 1 and
result.(SemBitAndExpr).hasOperands(arg, c)
)
}
/**
* Gets a guard that tests whether `v` is congruent with `val` modulo `mod` on
* its `testIsTrue` branch.
*/
private SemGuard moduloCheck(SemSsaVariable v, int val, int mod, boolean testIsTrue) {
exists(SemExpr rem, SemConstantIntegerExpr c, int r, boolean polarity |
result.isEquality(rem, c, polarity) and
c.getIntValue() = r and
rem = modExpr(v.getAUse(), mod) and
(
testIsTrue = polarity and val = r
or
testIsTrue = polarity.booleanNot() and
mod = 2 and
val = 1 - r and
(r = 0 or r = 1)
)
)
}
/**
* Holds if a guard ensures that `v` at `pos` is congruent with `val` modulo `mod`.
*/
private predicate moduloGuardedRead(SemSsaVariable v, SemSsaReadPosition pos, int val, int mod) {
exists(SemGuard guard, boolean testIsTrue |
pos.hasReadOfVar(v) and
guard = moduloCheck(v, val, mod, testIsTrue) and
semGuardControlsSsaRead(guard, pos, testIsTrue)
)
}
/** Holds if `factor` is a power of 2 that divides `mask`. */
bindingset[mask]
private predicate andmaskFactor(int mask, int factor) {
mask % factor = 0 and
factor = 2.pow([1 .. 30])
}
/** Holds if `e` is evenly divisible by `factor`. */
private predicate evenlyDivisibleExpr(SemExpr e, int factor) {
exists(SemConstantIntegerExpr c, int k | k = c.getIntValue() |
e.(SemMulExpr).getAnOperand() = c and factor = k.abs() and factor >= 2
or
e.(SemShiftLeftExpr).getRightOperand() = c and factor = 2.pow(k) and k > 0
or
e.(SemBitAndExpr).getAnOperand() = c and factor = max(int f | andmaskFactor(k, f))
)
}
/**
* Gets the remainder of `val` modulo `mod`.
*
* For `mod = 0` the result equals `val` and for `mod > 1` the result is within
* the range `[0 .. mod-1]`.
*/
bindingset[val, mod]
private int remainder(int val, int mod) {
mod = 0 and result = val
or
mod > 1 and result = ((val % mod) + mod) % mod
}
/**
* Holds if `inp` is an input to `phi` and equals `phi` modulo `mod` along `edge`.
*/
private predicate phiSelfModulus(
SemSsaPhiNode phi, SemSsaVariable inp, SemSsaReadPositionPhiInputEdge edge, int mod
) {
exists(Bounds::SemSsaBound phibound, int v, int m |
edge.phiInput(phi, inp) and
phibound.getAVariable() = phi and
ssaModulus(inp, edge, phibound, v, m) and
mod = m.gcd(v) and
mod != 1
)
}
/**
* Holds if `b + val` modulo `mod` is a candidate congruence class for `phi`.
*/
private predicate phiModulusInit(SemSsaPhiNode phi, Bounds::SemBound b, int val, int mod) {
exists(SemSsaVariable inp, SemSsaReadPositionPhiInputEdge edge |
edge.phiInput(phi, inp) and
ssaModulus(inp, edge, b, val, mod)
)
}
/**
* Holds if all inputs to `phi` numbered `1` to `rix` are equal to `b + val` modulo `mod`.
*/
pragma[nomagic]
private predicate phiModulusRankStep(
SemSsaPhiNode phi, Bounds::SemBound b, int val, int mod, int rix
) {
/*
* base case. If any phi input is equal to `b + val` modulo `mod`, that's a potential congruence
* class for the phi node.
*/
rix = 0 and
phiModulusInit(phi, b, val, mod)
or
exists(SemSsaVariable inp, SemSsaReadPositionPhiInputEdge edge, int v1, int m1 |
mod != 1 and
val = remainder(v1, mod)
|
/*
* Recursive case. If `inp` = `b + v2` mod `m2`, we combine that with the preceding potential
* congruence class `b + v1` mod `m1`. The result will be the congruence class of `v1` modulo
* the greatest common denominator of `m1`, `m2`, and `v1 - v2`.
*/
exists(int v2, int m2 |
rankedPhiInput(pragma[only_bind_out](phi), inp, edge, rix) and
phiModulusRankStep(phi, b, v1, m1, rix - 1) and
ssaModulus(inp, edge, b, v2, m2) and
mod = m1.gcd(m2).gcd(v1 - v2)
)
or
/*
* Recursive case. If `inp` = `phi` mod `m2`, we combine that with the preceding potential
* congruence class `b + v1` mod `m1`. The result will be a congruence class modulo the greatest
* common denominator of `m1` and `m2`.
*/
exists(int m2 |
rankedPhiInput(phi, inp, edge, rix) and
phiModulusRankStep(phi, b, v1, m1, rix - 1) and
phiSelfModulus(phi, inp, edge, m2) and
mod = m1.gcd(m2)
)
)
}
/**
* Holds if `phi` is equal to `b + val` modulo `mod`.
*/
private predicate phiModulus(SemSsaPhiNode phi, Bounds::SemBound b, int val, int mod) {
exists(int r |
maxPhiInputRank(phi, r) and
phiModulusRankStep(phi, b, val, mod, r)
)
}
/**
* Holds if `v` at `pos` is equal to `b + val` modulo `mod`.
*/
private predicate ssaModulus(
SemSsaVariable v, SemSsaReadPosition pos, Bounds::SemBound b, int val, int mod
) {
phiModulus(v, b, val, mod) and pos.hasReadOfVar(v)
or
b.(Bounds::SemSsaBound).getAVariable() = v and pos.hasReadOfVar(v) and val = 0 and mod = 0
or
exists(SemExpr e, int val0, int delta |
semExprModulus(e, b, val0, mod) and
valueFlowStepSsa(v, pos, e, delta) and
val = remainder(val0 + delta, mod)
)
or
moduloGuardedRead(v, pos, val, mod) and b instanceof Bounds::SemZeroBound
}
/**
* Holds if `e` is equal to `b + val` modulo `mod`.
*
* There are two cases for the modulus:
* - `mod = 0`: The equality `e = b + val` is an ordinary equality.
* - `mod > 1`: `val` lies within the range `[0 .. mod-1]`.
*/
cached
predicate semExprModulus(SemExpr e, Bounds::SemBound b, int val, int mod) {
not ignoreExprModulus(e) and
(
e = b.getExpr(D::fromInt(val)) and mod = 0
or
evenlyDivisibleExpr(e, mod) and
val = 0 and
b instanceof Bounds::SemZeroBound
or
exists(SemSsaVariable v, SemSsaReadPositionBlock bb |
ssaModulus(v, bb, b, val, mod) and
e = v.getAUse() and
bb.getAnExpr() = e
)
or
exists(SemExpr mid, int val0, int delta |
semExprModulus(mid, b, val0, mod) and
U::semValueFlowStep(e, mid, D::fromInt(delta)) and
val = remainder(val0 + delta, mod)
)
or
exists(SemConditionalExpr cond, int v1, int v2, int m1, int m2 |
cond = e and
condExprBranchModulus(cond, true, b, v1, m1) and
condExprBranchModulus(cond, false, b, v2, m2) and
mod = m1.gcd(m2).gcd(v1 - v2) and
mod != 1 and
val = remainder(v1, mod)
)
or
exists(Bounds::SemBound b1, Bounds::SemBound b2, int v1, int v2, int m1, int m2 |
addModulus(e, true, b1, v1, m1) and
addModulus(e, false, b2, v2, m2) and
mod = m1.gcd(m2) and
mod != 1 and
val = remainder(v1 + v2, mod)
|
b = b1 and b2 instanceof Bounds::SemZeroBound
or
b = b2 and b1 instanceof Bounds::SemZeroBound
)
or
exists(int v1, int v2, int m1, int m2 |
subModulus(e, true, b, v1, m1) and
subModulus(e, false, any(Bounds::SemZeroBound zb), v2, m2) and
mod = m1.gcd(m2) and
mod != 1 and
val = remainder(v1 - v2, mod)
)
)
}
private predicate condExprBranchModulus(
SemConditionalExpr cond, boolean branch, Bounds::SemBound b, int val, int mod
) {
semExprModulus(cond.getBranchExpr(branch), b, val, mod)
}
private predicate addModulus(SemExpr add, boolean isLeft, Bounds::SemBound b, int val, int mod) {
exists(SemExpr larg, SemExpr rarg | nonConstAddition(add, larg, rarg) |
semExprModulus(larg, b, val, mod) and isLeft = true
or
semExprModulus(rarg, b, val, mod) and isLeft = false
)
}
private predicate subModulus(SemExpr sub, boolean isLeft, Bounds::SemBound b, int val, int mod) {
exists(SemExpr larg, SemExpr rarg | nonConstSubtraction(sub, larg, rarg) |
semExprModulus(larg, b, val, mod) and isLeft = true
or
semExprModulus(rarg, b, val, mod) and isLeft = false
)
}
}

View File

@@ -0,0 +1,8 @@
/**
* C++-specific implementation of modulus analysis.
*/
module Private {
private import semmle.code.cpp.rangeanalysis.new.internal.semantic.Semantic
predicate ignoreExprModulus(SemExpr e) { none() }
}

View File

@@ -3,11 +3,18 @@
*/
private import semmle.code.cpp.rangeanalysis.new.internal.semantic.Semantic
private import RangeAnalysisStage
private import semmle.code.cpp.rangeanalysis.new.internal.semantic.analysis.FloatDelta
private import RangeAnalysisImpl
private import codeql.rangeanalysis.RangeAnalysis
module CppLangImplConstant implements LangSig<Sem, FloatDelta> {
module CppLangImplConstant implements LangSig<FloatDelta> {
/**
* Holds if the specified expression should be excluded from the result of `ssaRead()`.
*
* This predicate is to keep the results identical to the original Java implementation. It should be
* removed once we have the new implementation matching the old results exactly.
*/
predicate ignoreSsaReadCopy(SemExpr e) { none() }
/**
* Ignore the bound on this expression.
*
@@ -16,13 +23,70 @@ module CppLangImplConstant implements LangSig<Sem, FloatDelta> {
*/
predicate ignoreExprBound(SemExpr e) { none() }
/**
* Ignore any inferred zero lower bound on this expression.
*
* This predicate is to keep the results identical to the original Java implementation. It should be
* removed once we have the new implementation matching the old results exactly.
*/
predicate ignoreZeroLowerBound(SemExpr e) { none() }
/**
* Holds if the specified expression should be excluded from the result of `ssaRead()`.
*
* This predicate is to keep the results identical to the original Java implementation. It should be
* removed once we have the new implementation matching the old results exactly.
*/
predicate ignoreSsaReadArithmeticExpr(SemExpr e) { none() }
/**
* Holds if the specified variable should be excluded from the result of `ssaRead()`.
*
* This predicate is to keep the results identical to the original Java implementation. It should be
* removed once we have the new implementation matching the old results exactly.
*/
predicate ignoreSsaReadAssignment(SemSsaVariable v) { none() }
/**
* Adds additional results to `ssaRead()` that are specific to Java.
*
* This predicate handles propagation of offsets for post-increment and post-decrement expressions
* in exactly the same way as the old Java implementation. Once the new implementation matches the
* old one, we should remove this predicate and propagate deltas for all similar patterns, whether
* or not they come from a post-increment/decrement expression.
*/
SemExpr specificSsaRead(SemSsaVariable v, float delta) { none() }
/**
* Holds if `e >= bound` (if `upper = false`) or `e <= bound` (if `upper = true`).
*/
predicate hasConstantBound(SemExpr e, float bound, boolean upper) { none() }
/**
* Holds if `e2 >= e1 + delta` (if `upper = false`) or `e2 <= e1 + delta` (if `upper = true`).
* Holds if `e >= bound + delta` (if `upper = false`) or `e <= bound + delta` (if `upper = true`).
*/
predicate additionalBoundFlowStep(SemExpr e2, SemExpr e1, float delta, boolean upper) { none() }
predicate hasBound(SemExpr e, SemExpr bound, float delta, boolean upper) { none() }
/**
* Holds if the value of `dest` is known to be `src + delta`.
*/
predicate additionalValueFlowStep(SemExpr dest, SemExpr src, float delta) { none() }
/**
* Gets the type that range analysis should use to track the result of the specified expression,
* if a type other than the original type of the expression is to be used.
*
* This predicate is commonly used in languages that support immutable "boxed" types that are
* actually references but whose values can be tracked as the type contained in the box.
*/
SemType getAlternateType(SemExpr e) { none() }
/**
* Gets the type that range analysis should use to track the result of the specified source
* variable, if a type other than the original type of the expression is to be used.
*
* This predicate is commonly used in languages that support immutable "boxed" types that are
* actually references but whose values can be tracked as the type contained in the box.
*/
SemType getAlternateTypeForSsaVariable(SemSsaVariable var) { none() }
}

View File

@@ -1,115 +1,13 @@
private import RangeAnalysisStage
private import RangeAnalysisConstantSpecific
private import RangeAnalysisRelativeSpecific
private import semmle.code.cpp.rangeanalysis.new.internal.semantic.analysis.FloatDelta
private import semmle.code.cpp.rangeanalysis.new.internal.semantic.SemanticExpr
private import semmle.code.cpp.rangeanalysis.new.internal.semantic.SemanticCFG
private import semmle.code.cpp.rangeanalysis.new.internal.semantic.SemanticGuard
private import RangeUtils
private import semmle.code.cpp.rangeanalysis.new.internal.semantic.SemanticBound as SemanticBound
private import semmle.code.cpp.rangeanalysis.new.internal.semantic.SemanticLocation
private import semmle.code.cpp.rangeanalysis.new.internal.semantic.SemanticSSA
private import semmle.code.cpp.rangeanalysis.new.internal.semantic.SemanticType as SemanticType
private import SemanticType
private import codeql.rangeanalysis.RangeAnalysis
private import ConstantAnalysis as ConstantAnalysis
module Sem implements Semantic {
class Expr = SemExpr;
class ConstantIntegerExpr = ConstantAnalysis::SemConstantIntegerExpr;
class BinaryExpr = SemBinaryExpr;
class AddExpr = SemAddExpr;
class SubExpr = SemSubExpr;
class MulExpr = SemMulExpr;
class DivExpr = SemDivExpr;
class RemExpr = SemRemExpr;
class BitAndExpr = SemBitAndExpr;
class BitOrExpr = SemBitOrExpr;
class ShiftLeftExpr = SemShiftLeftExpr;
class ShiftRightExpr = SemShiftRightExpr;
class ShiftRightUnsignedExpr = SemShiftRightUnsignedExpr;
class RelationalExpr = SemRelationalExpr;
class UnaryExpr = SemUnaryExpr;
class ConvertExpr = SemConvertExpr;
class BoxExpr = SemBoxExpr;
class UnboxExpr = SemUnboxExpr;
class NegateExpr = SemNegateExpr;
class PreIncExpr = SemAddOneExpr;
class PreDecExpr = SemSubOneExpr;
class PostIncExpr extends SemUnaryExpr {
PostIncExpr() { none() }
}
class PostDecExpr extends SemUnaryExpr {
PostDecExpr() { none() }
}
class CopyValueExpr extends SemUnaryExpr {
CopyValueExpr() { this instanceof SemCopyValueExpr or this instanceof SemStoreExpr }
}
class ConditionalExpr = SemConditionalExpr;
class BasicBlock = SemBasicBlock;
BasicBlock getABasicBlockSuccessor(BasicBlock bb) { result = bb.getASuccessor() }
int getBlockId1(BasicBlock bb) { result = bb.getUniqueId() }
class Guard = SemGuard;
predicate implies_v2 = semImplies_v2/4;
class Type = SemType;
class IntegerType = SemIntegerType;
class FloatingPointType = SemFloatingPointType;
class AddressType = SemAddressType;
SemType getExprType(SemExpr e) { result = e.getSemType() }
SemType getSsaType(SemSsaVariable var) { result = var.getType() }
class SsaVariable = SemSsaVariable;
class SsaPhiNode = SemSsaPhiNode;
class SsaExplicitUpdate = SemSsaExplicitUpdate;
predicate additionalValueFlowStep(SemExpr dest, SemExpr src, int delta) { none() }
predicate conversionCannotOverflow(Type fromType, Type toType) {
SemanticType::conversionCannotOverflow(fromType, toType)
}
}
module SignAnalysis implements SignAnalysisSig<Sem> {
private import SignAnalysisCommon as SA
import SA::SignAnalysis<FloatDelta>
}
module ConstantBounds implements BoundSig<SemLocation, Sem, FloatDelta> {
module ConstantBounds implements BoundSig<FloatDelta> {
class SemBound instanceof SemanticBound::SemBound {
SemBound() {
this instanceof SemanticBound::SemZeroBound
@@ -127,11 +25,11 @@ module ConstantBounds implements BoundSig<SemLocation, Sem, FloatDelta> {
class SemZeroBound extends SemBound instanceof SemanticBound::SemZeroBound { }
class SemSsaBound extends SemBound instanceof SemanticBound::SemSsaBound {
SemSsaVariable getVariable() { result = this.(SemanticBound::SemSsaBound).getAVariable() }
SemSsaVariable getAVariable() { result = this.(SemanticBound::SemSsaBound).getAVariable() }
}
}
module RelativeBounds implements BoundSig<SemLocation, Sem, FloatDelta> {
module RelativeBounds implements BoundSig<FloatDelta> {
class SemBound instanceof SemanticBound::SemBound {
SemBound() { not this instanceof SemanticBound::SemZeroBound }
@@ -145,40 +43,17 @@ module RelativeBounds implements BoundSig<SemLocation, Sem, FloatDelta> {
class SemZeroBound extends SemBound instanceof SemanticBound::SemZeroBound { }
class SemSsaBound extends SemBound instanceof SemanticBound::SemSsaBound {
SemSsaVariable getVariable() { result = this.(SemanticBound::SemSsaBound).getAVariable() }
SemSsaVariable getAVariable() { result = this.(SemanticBound::SemSsaBound).getAVariable() }
}
}
module AllBounds implements BoundSig<SemLocation, Sem, FloatDelta> {
class SemBound instanceof SemanticBound::SemBound {
string toString() { result = super.toString() }
SemLocation getLocation() { result = super.getLocation() }
SemExpr getExpr(float delta) { result = super.getExpr(delta) }
}
class SemZeroBound extends SemBound instanceof SemanticBound::SemZeroBound { }
class SemSsaBound extends SemBound instanceof SemanticBound::SemSsaBound {
SemSsaVariable getVariable() { result = this.(SemanticBound::SemSsaBound).getAVariable() }
}
}
private module ModulusAnalysisInstantiated implements ModulusAnalysisSig<Sem> {
class ModBound = AllBounds::SemBound;
private import codeql.rangeanalysis.ModulusAnalysis as MA
import MA::ModulusAnalysis<SemLocation, Sem, FloatDelta, AllBounds>
}
module ConstantStage =
RangeStage<SemLocation, Sem, FloatDelta, ConstantBounds, FloatOverflow, CppLangImplConstant,
SignAnalysis, ModulusAnalysisInstantiated>;
RangeStage<FloatDelta, ConstantBounds, FloatOverflow, CppLangImplConstant,
RangeUtil<FloatDelta, CppLangImplConstant>>;
module RelativeStage =
RangeStage<SemLocation, Sem, FloatDelta, RelativeBounds, FloatOverflow, CppLangImplRelative,
SignAnalysis, ModulusAnalysisInstantiated>;
RangeStage<FloatDelta, RelativeBounds, FloatOverflow, CppLangImplRelative,
RangeUtil<FloatDelta, CppLangImplRelative>>;
private newtype TSemReason =
TSemNoReason() or

View File

@@ -3,12 +3,21 @@
*/
private import semmle.code.cpp.rangeanalysis.new.internal.semantic.Semantic
private import RangeAnalysisStage
private import semmle.code.cpp.rangeanalysis.new.internal.semantic.analysis.FloatDelta
private import semmle.code.cpp.rangeanalysis.new.internal.semantic.analysis.IntDelta
private import RangeAnalysisImpl
private import semmle.code.cpp.rangeanalysis.RangeAnalysisUtils
private import codeql.rangeanalysis.RangeAnalysis
module CppLangImplRelative implements LangSig<Sem, FloatDelta> {
module CppLangImplRelative implements LangSig<FloatDelta> {
/**
* Holds if the specified expression should be excluded from the result of `ssaRead()`.
*
* This predicate is to keep the results identical to the original Java implementation. It should be
* removed once we have the new implementation matching the old results exactly.
*/
predicate ignoreSsaReadCopy(SemExpr e) { none() }
/**
* Ignore the bound on this expression.
*
@@ -48,13 +57,70 @@ module CppLangImplRelative implements LangSig<Sem, FloatDelta> {
t instanceof SemFloatingPointType and lb = -(1.0 / 0.0) and ub = 1.0 / 0.0
}
/**
* Ignore any inferred zero lower bound on this expression.
*
* This predicate is to keep the results identical to the original Java implementation. It should be
* removed once we have the new implementation matching the old results exactly.
*/
predicate ignoreZeroLowerBound(SemExpr e) { none() }
/**
* Holds if the specified expression should be excluded from the result of `ssaRead()`.
*
* This predicate is to keep the results identical to the original Java implementation. It should be
* removed once we have the new implementation matching the old results exactly.
*/
predicate ignoreSsaReadArithmeticExpr(SemExpr e) { none() }
/**
* Holds if the specified variable should be excluded from the result of `ssaRead()`.
*
* This predicate is to keep the results identical to the original Java implementation. It should be
* removed once we have the new implementation matching the old results exactly.
*/
predicate ignoreSsaReadAssignment(SemSsaVariable v) { none() }
/**
* Adds additional results to `ssaRead()` that are specific to Java.
*
* This predicate handles propagation of offsets for post-increment and post-decrement expressions
* in exactly the same way as the old Java implementation. Once the new implementation matches the
* old one, we should remove this predicate and propagate deltas for all similar patterns, whether
* or not they come from a post-increment/decrement expression.
*/
SemExpr specificSsaRead(SemSsaVariable v, float delta) { none() }
/**
* Holds if `e >= bound` (if `upper = false`) or `e <= bound` (if `upper = true`).
*/
predicate hasConstantBound(SemExpr e, float bound, boolean upper) { none() }
/**
* Holds if `e2 >= e1 + delta` (if `upper = false`) or `e2 <= e1 + delta` (if `upper = true`).
* Holds if `e >= bound + delta` (if `upper = false`) or `e <= bound + delta` (if `upper = true`).
*/
predicate additionalBoundFlowStep(SemExpr e2, SemExpr e1, float delta, boolean upper) { none() }
predicate hasBound(SemExpr e, SemExpr bound, float delta, boolean upper) { none() }
/**
* Holds if the value of `dest` is known to be `src + delta`.
*/
predicate additionalValueFlowStep(SemExpr dest, SemExpr src, float delta) { none() }
/**
* Gets the type that range analysis should use to track the result of the specified expression,
* if a type other than the original type of the expression is to be used.
*
* This predicate is commonly used in languages that support immutable "boxed" types that are
* actually references but whose values can be tracked as the type contained in the box.
*/
SemType getAlternateType(SemExpr e) { none() }
/**
* Gets the type that range analysis should use to track the result of the specified source
* variable, if a type other than the original type of the expression is to be used.
*
* This predicate is commonly used in languages that support immutable "boxed" types that are
* actually references but whose values can be tracked as the type contained in the box.
*/
SemType getAlternateTypeForSsaVariable(SemSsaVariable var) { none() }
}

View File

@@ -0,0 +1,164 @@
/**
* Provides utility predicates for range analysis.
*/
private import semmle.code.cpp.rangeanalysis.new.internal.semantic.Semantic
private import RangeAnalysisRelativeSpecific
private import RangeAnalysisStage as Range
private import ConstantAnalysis
module RangeUtil<Range::DeltaSig D, Range::LangSig<D> Lang> implements Range::UtilSig<D> {
/**
* Gets an expression that equals `v - d`.
*/
SemExpr semSsaRead(SemSsaVariable v, D::Delta delta) {
// There are various language-specific extension points that can be removed once we no longer
// expect to match the original Java implementation's results exactly.
result = v.getAUse() and delta = D::fromInt(0)
or
exists(D::Delta d1, SemConstantIntegerExpr c |
result.(SemAddExpr).hasOperands(semSsaRead(v, d1), c) and
delta = D::fromFloat(D::toFloat(d1) - c.getIntValue()) and
not Lang::ignoreSsaReadArithmeticExpr(result)
)
or
exists(SemSubExpr sub, D::Delta d1, SemConstantIntegerExpr c |
result = sub and
sub.getLeftOperand() = semSsaRead(v, d1) and
sub.getRightOperand() = c and
delta = D::fromFloat(D::toFloat(d1) + c.getIntValue()) and
not Lang::ignoreSsaReadArithmeticExpr(result)
)
or
result = v.(SemSsaExplicitUpdate).getSourceExpr() and
delta = D::fromFloat(0) and
not Lang::ignoreSsaReadAssignment(v)
or
result = Lang::specificSsaRead(v, delta)
or
result.(SemCopyValueExpr).getOperand() = semSsaRead(v, delta) and
not Lang::ignoreSsaReadCopy(result)
or
result.(SemStoreExpr).getOperand() = semSsaRead(v, delta)
}
/**
* Gets a condition that tests whether `v` equals `e + delta`.
*
* If the condition evaluates to `testIsTrue`:
* - `isEq = true` : `v == e + delta`
* - `isEq = false` : `v != e + delta`
*/
pragma[nomagic]
SemGuard semEqFlowCond(
SemSsaVariable v, SemExpr e, D::Delta delta, boolean isEq, boolean testIsTrue
) {
exists(boolean eqpolarity |
result.isEquality(semSsaRead(v, delta), e, eqpolarity) and
(testIsTrue = true or testIsTrue = false) and
eqpolarity.booleanXor(testIsTrue).booleanNot() = isEq
)
or
exists(boolean testIsTrue0 |
semImplies_v2(result, testIsTrue, semEqFlowCond(v, e, delta, isEq, testIsTrue0), testIsTrue0)
)
}
/**
* Holds if `v` is an `SsaExplicitUpdate` that equals `e + delta`.
*/
predicate semSsaUpdateStep(SemSsaExplicitUpdate v, SemExpr e, D::Delta delta) {
exists(SemExpr defExpr | defExpr = v.getSourceExpr() |
defExpr.(SemCopyValueExpr).getOperand() = e and delta = D::fromFloat(0)
or
defExpr.(SemStoreExpr).getOperand() = e and delta = D::fromFloat(0)
or
defExpr.(SemAddOneExpr).getOperand() = e and delta = D::fromFloat(1)
or
defExpr.(SemSubOneExpr).getOperand() = e and delta = D::fromFloat(-1)
or
e = defExpr and
not (
defExpr instanceof SemCopyValueExpr or
defExpr instanceof SemStoreExpr or
defExpr instanceof SemAddOneExpr or
defExpr instanceof SemSubOneExpr
) and
delta = D::fromFloat(0)
)
}
/**
* Holds if `e1 + delta` equals `e2`.
*/
predicate semValueFlowStep(SemExpr e2, SemExpr e1, D::Delta delta) {
e2.(SemCopyValueExpr).getOperand() = e1 and delta = D::fromFloat(0)
or
e2.(SemStoreExpr).getOperand() = e1 and delta = D::fromFloat(0)
or
e2.(SemAddOneExpr).getOperand() = e1 and delta = D::fromFloat(1)
or
e2.(SemSubOneExpr).getOperand() = e1 and delta = D::fromFloat(-1)
or
Lang::additionalValueFlowStep(e2, e1, delta)
or
exists(SemExpr x | e2.(SemAddExpr).hasOperands(e1, x) |
D::fromInt(x.(SemConstantIntegerExpr).getIntValue()) = delta
)
or
exists(SemExpr x, SemSubExpr sub |
e2 = sub and
sub.getLeftOperand() = e1 and
sub.getRightOperand() = x
|
D::fromInt(-x.(SemConstantIntegerExpr).getIntValue()) = delta
)
}
/**
* Gets the type used to track the specified expression's range information.
*
* Usually, this just `e.getSemType()`, but the language can override this to track immutable boxed
* primitive types as the underlying primitive type.
*/
SemType getTrackedType(SemExpr e) {
result = Lang::getAlternateType(e)
or
not exists(Lang::getAlternateType(e)) and result = e.getSemType()
}
/**
* Gets the type used to track the specified source variable's range information.
*
* Usually, this just `e.getType()`, but the language can override this to track immutable boxed
* primitive types as the underlying primitive type.
*/
SemType getTrackedTypeForSsaVariable(SemSsaVariable var) {
result = Lang::getAlternateTypeForSsaVariable(var)
or
not exists(Lang::getAlternateTypeForSsaVariable(var)) and result = var.getType()
}
}
/**
* Holds if `rix` is the number of input edges to `phi`.
*/
predicate maxPhiInputRank(SemSsaPhiNode phi, int rix) {
rix = max(int r | rankedPhiInput(phi, _, _, r))
}
/**
* Holds if `inp` is an input to `phi` along `edge` and this input has index `r`
* in an arbitrary 1-based numbering of the input edges to `phi`.
*/
predicate rankedPhiInput(
SemSsaPhiNode phi, SemSsaVariable inp, SemSsaReadPositionPhiInputEdge edge, int r
) {
edge.phiInput(phi, inp) and
edge =
rank[r](SemSsaReadPositionPhiInputEdge e |
e.phiInput(phi, _)
|
e order by e.getOrigBlock().getUniqueId()
)
}

View File

@@ -6,16 +6,14 @@
* three-valued domain `{negative, zero, positive}`.
*/
private import codeql.rangeanalysis.RangeAnalysis
private import RangeAnalysisImpl
private import RangeAnalysisStage
private import SignAnalysisSpecific as Specific
private import semmle.code.cpp.rangeanalysis.new.internal.semantic.Semantic
private import ConstantAnalysis
private import RangeUtils
private import Sign
module SignAnalysis<DeltaSig D> {
private import codeql.rangeanalysis.internal.RangeUtils::MakeUtils<Sem, D>
module SignAnalysis<DeltaSig D, UtilSig<D> Utils> {
/**
* An SSA definition for which the analysis can compute the sign.
*
@@ -38,13 +36,13 @@ module SignAnalysis<DeltaSig D> {
/** An SSA definition whose sign is determined by the sign of that definitions source expression. */
private class ExplicitSignDef extends FlowSignDef instanceof SemSsaExplicitUpdate {
final override Sign getSign() { result = semExprSign(super.getDefiningExpr()) }
final override Sign getSign() { result = semExprSign(super.getSourceExpr()) }
}
/** An SSA Phi definition, whose sign is the union of the signs of its inputs. */
private class PhiSignDef extends FlowSignDef instanceof SemSsaPhiNode {
final override Sign getSign() {
exists(SemSsaVariable inp, SsaReadPositionPhiInputEdge edge |
exists(SemSsaVariable inp, SemSsaReadPositionPhiInputEdge edge |
edge.phiInput(this, inp) and
result = semSsaSign(inp, edge)
)
@@ -147,7 +145,7 @@ module SignAnalysis<DeltaSig D> {
not this instanceof ConstantSignExpr and
(
// Only track numeric types.
Sem::getExprType(this) instanceof SemNumericType
Utils::getTrackedType(this) instanceof SemNumericType
or
// Unless the language says to track this expression anyway.
Specific::trackUnknownNonNumericExpr(this)
@@ -169,11 +167,11 @@ module SignAnalysis<DeltaSig D> {
override Sign getSignRestriction() {
// Propagate via SSA
// Propagate the sign from the def of `v`, incorporating any inference from guards.
result = semSsaSign(v, any(SsaReadPositionBlock bb | bb.getBlock().getAnExpr() = this))
result = semSsaSign(v, any(SemSsaReadPositionBlock bb | bb.getAnExpr() = this))
or
// No block for this read. Just use the sign of the def.
// REVIEW: How can this happen?
not exists(SsaReadPositionBlock bb | bb.getBlock().getAnExpr() = this) and
not exists(SemSsaReadPositionBlock bb | bb.getAnExpr() = this) and
result = semSsaDefSign(v)
}
}
@@ -202,7 +200,7 @@ module SignAnalysis<DeltaSig D> {
/** An expression of an unsigned type. */
private class UnsignedExpr extends FlowSignExpr {
UnsignedExpr() { Sem::getExprType(this) instanceof SemUnsignedIntegerType }
UnsignedExpr() { Utils::getTrackedType(this) instanceof SemUnsignedIntegerType }
override Sign getSignRestriction() {
result = TPos() or
@@ -275,7 +273,7 @@ module SignAnalysis<DeltaSig D> {
override SemUnboxExpr cast;
UnboxSignExpr() {
exists(SemType fromType | fromType = Sem::getExprType(cast.getOperand()) |
exists(SemType fromType | fromType = Utils::getTrackedType(cast.getOperand()) |
// Only numeric source types are handled here.
fromType instanceof SemNumericType
)
@@ -289,21 +287,21 @@ module SignAnalysis<DeltaSig D> {
* to only include bounds for which we might determine a sign.
*/
private predicate lowerBound(
SemExpr lowerbound, SemSsaVariable v, SsaReadPosition pos, boolean isStrict
SemExpr lowerbound, SemSsaVariable v, SemSsaReadPosition pos, boolean isStrict
) {
exists(boolean testIsTrue, SemRelationalExpr comp |
pos.hasReadOfVar(v) and
guardControlsSsaRead(semGetComparisonGuard(comp), pos, testIsTrue) and
semGuardControlsSsaRead(semGetComparisonGuard(comp), pos, testIsTrue) and
not unknownSign(lowerbound)
|
testIsTrue = true and
comp.getLesserOperand() = lowerbound and
comp.getGreaterOperand() = ssaRead(v, D::fromInt(0)) and
comp.getGreaterOperand() = Utils::semSsaRead(v, D::fromInt(0)) and
(if comp.isStrict() then isStrict = true else isStrict = false)
or
testIsTrue = false and
comp.getGreaterOperand() = lowerbound and
comp.getLesserOperand() = ssaRead(v, D::fromInt(0)) and
comp.getLesserOperand() = Utils::semSsaRead(v, D::fromInt(0)) and
(if comp.isStrict() then isStrict = false else isStrict = true)
)
}
@@ -313,21 +311,21 @@ module SignAnalysis<DeltaSig D> {
* to only include bounds for which we might determine a sign.
*/
private predicate upperBound(
SemExpr upperbound, SemSsaVariable v, SsaReadPosition pos, boolean isStrict
SemExpr upperbound, SemSsaVariable v, SemSsaReadPosition pos, boolean isStrict
) {
exists(boolean testIsTrue, SemRelationalExpr comp |
pos.hasReadOfVar(v) and
guardControlsSsaRead(semGetComparisonGuard(comp), pos, testIsTrue) and
semGuardControlsSsaRead(semGetComparisonGuard(comp), pos, testIsTrue) and
not unknownSign(upperbound)
|
testIsTrue = true and
comp.getGreaterOperand() = upperbound and
comp.getLesserOperand() = ssaRead(v, D::fromInt(0)) and
comp.getLesserOperand() = Utils::semSsaRead(v, D::fromInt(0)) and
(if comp.isStrict() then isStrict = true else isStrict = false)
or
testIsTrue = false and
comp.getLesserOperand() = upperbound and
comp.getGreaterOperand() = ssaRead(v, D::fromInt(0)) and
comp.getGreaterOperand() = Utils::semSsaRead(v, D::fromInt(0)) and
(if comp.isStrict() then isStrict = false else isStrict = true)
)
}
@@ -339,11 +337,11 @@ module SignAnalysis<DeltaSig D> {
* - `isEq = true` : `v = eqbound`
* - `isEq = false` : `v != eqbound`
*/
private predicate eqBound(SemExpr eqbound, SemSsaVariable v, SsaReadPosition pos, boolean isEq) {
private predicate eqBound(SemExpr eqbound, SemSsaVariable v, SemSsaReadPosition pos, boolean isEq) {
exists(SemGuard guard, boolean testIsTrue, boolean polarity, SemExpr e |
pos.hasReadOfVar(pragma[only_bind_into](v)) and
guardControlsSsaRead(guard, pragma[only_bind_into](pos), testIsTrue) and
e = ssaRead(pragma[only_bind_into](v), D::fromInt(0)) and
semGuardControlsSsaRead(guard, pragma[only_bind_into](pos), testIsTrue) and
e = Utils::semSsaRead(pragma[only_bind_into](v), D::fromInt(0)) and
guard.isEquality(eqbound, e, polarity) and
isEq = polarity.booleanXor(testIsTrue).booleanNot() and
not unknownSign(eqbound)
@@ -354,7 +352,7 @@ module SignAnalysis<DeltaSig D> {
* Holds if `bound` is a bound for `v` at `pos` that needs to be positive in
* order for `v` to be positive.
*/
private predicate posBound(SemExpr bound, SemSsaVariable v, SsaReadPosition pos) {
private predicate posBound(SemExpr bound, SemSsaVariable v, SemSsaReadPosition pos) {
upperBound(bound, v, pos, _) or
eqBound(bound, v, pos, true)
}
@@ -363,7 +361,7 @@ module SignAnalysis<DeltaSig D> {
* Holds if `bound` is a bound for `v` at `pos` that needs to be negative in
* order for `v` to be negative.
*/
private predicate negBound(SemExpr bound, SemSsaVariable v, SsaReadPosition pos) {
private predicate negBound(SemExpr bound, SemSsaVariable v, SemSsaReadPosition pos) {
lowerBound(bound, v, pos, _) or
eqBound(bound, v, pos, true)
}
@@ -372,24 +370,24 @@ module SignAnalysis<DeltaSig D> {
* Holds if `bound` is a bound for `v` at `pos` that can restrict whether `v`
* can be zero.
*/
private predicate zeroBound(SemExpr bound, SemSsaVariable v, SsaReadPosition pos) {
private predicate zeroBound(SemExpr bound, SemSsaVariable v, SemSsaReadPosition pos) {
lowerBound(bound, v, pos, _) or
upperBound(bound, v, pos, _) or
eqBound(bound, v, pos, _)
}
/** Holds if `bound` allows `v` to be positive at `pos`. */
private predicate posBoundOk(SemExpr bound, SemSsaVariable v, SsaReadPosition pos) {
private predicate posBoundOk(SemExpr bound, SemSsaVariable v, SemSsaReadPosition pos) {
posBound(bound, v, pos) and TPos() = semExprSign(bound)
}
/** Holds if `bound` allows `v` to be negative at `pos`. */
private predicate negBoundOk(SemExpr bound, SemSsaVariable v, SsaReadPosition pos) {
private predicate negBoundOk(SemExpr bound, SemSsaVariable v, SemSsaReadPosition pos) {
negBound(bound, v, pos) and TNeg() = semExprSign(bound)
}
/** Holds if `bound` allows `v` to be zero at `pos`. */
private predicate zeroBoundOk(SemExpr bound, SemSsaVariable v, SsaReadPosition pos) {
private predicate zeroBoundOk(SemExpr bound, SemSsaVariable v, SemSsaReadPosition pos) {
lowerBound(bound, v, pos, _) and TNeg() = semExprSign(bound)
or
lowerBound(bound, v, pos, false) and TZero() = semExprSign(bound)
@@ -407,7 +405,7 @@ module SignAnalysis<DeltaSig D> {
* Holds if there is a bound that might restrict whether `v` has the sign `s`
* at `pos`.
*/
private predicate hasGuard(SemSsaVariable v, SsaReadPosition pos, Sign s) {
private predicate hasGuard(SemSsaVariable v, SemSsaReadPosition pos, Sign s) {
s = TPos() and posBound(_, v, pos)
or
s = TNeg() and negBound(_, v, pos)
@@ -420,7 +418,7 @@ module SignAnalysis<DeltaSig D> {
* might be ruled out by a guard.
*/
pragma[noinline]
private Sign guardedSsaSign(SemSsaVariable v, SsaReadPosition pos) {
private Sign guardedSsaSign(SemSsaVariable v, SemSsaReadPosition pos) {
result = semSsaDefSign(v) and
pos.hasReadOfVar(v) and
hasGuard(v, pos, result)
@@ -431,7 +429,7 @@ module SignAnalysis<DeltaSig D> {
* can rule it out.
*/
pragma[noinline]
private Sign unguardedSsaSign(SemSsaVariable v, SsaReadPosition pos) {
private Sign unguardedSsaSign(SemSsaVariable v, SemSsaReadPosition pos) {
result = semSsaDefSign(v) and
pos.hasReadOfVar(v) and
not hasGuard(v, pos, result)
@@ -442,7 +440,7 @@ module SignAnalysis<DeltaSig D> {
* ruled out the sign but does not.
* This does not check that the definition of `v` also allows the sign.
*/
private Sign guardedSsaSignOk(SemSsaVariable v, SsaReadPosition pos) {
private Sign guardedSsaSignOk(SemSsaVariable v, SemSsaReadPosition pos) {
result = TPos() and
forex(SemExpr bound | posBound(bound, v, pos) | posBoundOk(bound, v, pos))
or
@@ -454,7 +452,7 @@ module SignAnalysis<DeltaSig D> {
}
/** Gets a possible sign for `v` at `pos`. */
private Sign semSsaSign(SemSsaVariable v, SsaReadPosition pos) {
private Sign semSsaSign(SemSsaVariable v, SemSsaReadPosition pos) {
result = unguardedSsaSign(v, pos)
or
result = guardedSsaSign(v, pos) and
@@ -470,7 +468,7 @@ module SignAnalysis<DeltaSig D> {
Sign semExprSign(SemExpr e) {
exists(Sign s | s = e.(SignExpr).getSign() |
if
Sem::getExprType(e) instanceof SemUnsignedIntegerType and
Utils::getTrackedType(e) instanceof SemUnsignedIntegerType and
s = TNeg() and
not Specific::ignoreTypeRestrictions(e)
then result = TPos()
@@ -509,16 +507,4 @@ module SignAnalysis<DeltaSig D> {
not semExprSign(e) = TPos() and
not semExprSign(e) = TZero()
}
/**
* Holds if `e` may have positive values. This does not rule out the
* possibility for negative values.
*/
predicate semMayBePositive(SemExpr e) { semExprSign(e) = TPos() }
/**
* Holds if `e` may have negative values. This does not rule out the
* possibility for positive values.
*/
predicate semMayBeNegative(SemExpr e) { semExprSign(e) = TNeg() }
}

View File

@@ -23,7 +23,9 @@
* configuration (see `InvalidPointerToDerefConfig`).
*
* The dataflow traversal defines the set of sources as any dataflow node `n` such that there exists a pointer-arithmetic
* instruction `pai` found by `AllocationToInvalidPointer.qll` and a `n.asInstruction() = pai`.
* instruction `pai` found by `AllocationToInvalidPointer.qll` and a `n.asInstruction() >= pai + deltaDerefSourceAndPai`.
* Here, `deltaDerefSourceAndPai` is the constant difference between the source we track for finding a dereference and the
* pointer-arithmetic instruction.
*
* The set of sinks is defined as any dataflow node `n` such that `addr <= n.asInstruction() + deltaDerefSinkAndDerefAddress`
* for some address operand `addr` and constant difference `deltaDerefSinkAndDerefAddress`. Since an address operand is
@@ -35,8 +37,9 @@
* `deltaDerefSinkAndDerefAddress >= 0`. The load attached to `*p` is the "operation". To ensure that the path makes
* intuitive sense, we only pick operations that are control-flow reachable from the dereference sink.
*
* We use the `deltaDerefSinkAndDerefAddress` to compute how many elements the dereference is beyond the end position of
* the allocation. This is done in the `operationIsOffBy` predicate (which is the only predicate exposed by this file).
* To compute how many elements the dereference is beyond the end position of the allocation, we sum the two deltas
* `deltaDerefSourceAndPai` and `deltaDerefSinkAndDerefAddress`. This is done in the `operationIsOffBy` predicate
* (which is the only predicate exposed by this file).
*
* Handling false positives:
*
@@ -93,7 +96,7 @@ int invalidPointerToDereferenceFieldFlowBranchLimit() { result = 0 }
private module InvalidPointerToDerefBarrier {
private module BarrierConfig implements DataFlow::ConfigSig {
additional predicate isSource(DataFlow::Node source, PointerArithmeticInstruction pai) {
invalidPointerToDerefSource(_, pai, _) and
invalidPointerToDerefSource(_, pai, _, _) and
// source <= pai
bounded2(source.asInstruction(), pai, any(int d | d <= 0))
}
@@ -166,11 +169,11 @@ private module InvalidPointerToDerefBarrier {
*/
private module InvalidPointerToDerefConfig implements DataFlow::StateConfigSig {
class FlowState extends PointerArithmeticInstruction {
FlowState() { invalidPointerToDerefSource(_, this, _) }
FlowState() { invalidPointerToDerefSource(_, this, _, _) }
}
predicate isSource(DataFlow::Node source, FlowState pai) {
invalidPointerToDerefSource(_, pai, source)
invalidPointerToDerefSource(_, pai, source, _)
}
pragma[inline]
@@ -195,17 +198,24 @@ private import DataFlow::GlobalWithState<InvalidPointerToDerefConfig>
/**
* Holds if `allocSource` is dataflow node that represents an allocation that flows to the
* left-hand side of the pointer-arithmetic instruction represented by `derefSource`.
* left-hand side of the pointer-arithmetic `pai`, and `derefSource <= pai + derefSourcePaiDelta`.
*
* For example, if `pai` is a pointer-arithmetic operation `p + size` in an expression such
* as `(p + size) + 1` and `derefSource` is the node representing `(p + size) + 1`. In this
* case `derefSourcePaiDelta` is 1.
*/
private predicate invalidPointerToDerefSource(
DataFlow::Node allocSource, PointerArithmeticInstruction pai, DataFlow::Node derefSource
DataFlow::Node allocSource, PointerArithmeticInstruction pai, DataFlow::Node derefSource,
int deltaDerefSourceAndPai
) {
// Note that `deltaDerefSourceAndPai` is not necessarily equal to `rhsSizeDelta`:
// `rhsSizeDelta` is the constant offset added to the size of the allocation, and
// `deltaDerefSourceAndPai` is the constant difference between the pointer-arithmetic instruction
// and the instruction computing the address for which we will search for a dereference.
AllocToInvalidPointer::pointerAddInstructionHasBounds(allocSource, pai, _, _) and
derefSource.asInstruction() = pai
// derefSource <= pai + deltaDerefSourceAndPai
bounded2(derefSource.asInstruction(), pai, deltaDerefSourceAndPai) and
deltaDerefSourceAndPai >= 0
}
/**
@@ -248,9 +258,11 @@ private Instruction getASuccessor(Instruction instr) {
instr.getBlock().getASuccessor+() = result.getBlock()
}
private predicate paiForDereferenceSink(PointerArithmeticInstruction pai, DataFlow::Node derefSink) {
private predicate paiForDereferenceSink(
PointerArithmeticInstruction pai, DataFlow::Node derefSink, int deltaDerefSourceAndPai
) {
exists(DataFlow::Node derefSource |
invalidPointerToDerefSource(_, pai, derefSource) and
invalidPointerToDerefSource(_, pai, derefSource, deltaDerefSourceAndPai) and
flow(derefSource, derefSink)
)
}
@@ -262,10 +274,10 @@ private predicate paiForDereferenceSink(PointerArithmeticInstruction pai, DataFl
*/
private predicate derefSinkToOperation(
DataFlow::Node derefSink, PointerArithmeticInstruction pai, DataFlow::Node operation,
string description, int deltaDerefSinkAndDerefAddress
string description, int deltaDerefSourceAndPai, int deltaDerefSinkAndDerefAddress
) {
exists(Instruction operationInstr, AddressOperand addr |
paiForDereferenceSink(pai, pragma[only_bind_into](derefSink)) and
paiForDereferenceSink(pai, pragma[only_bind_into](derefSink), deltaDerefSourceAndPai) and
isInvalidPointerDerefSink(derefSink, addr, operationInstr, description,
deltaDerefSinkAndDerefAddress) and
operationInstr = getASuccessor(derefSink.asInstruction()) and
@@ -286,7 +298,11 @@ predicate operationIsOffBy(
DataFlow::Node allocation, PointerArithmeticInstruction pai, DataFlow::Node derefSource,
DataFlow::Node derefSink, string description, DataFlow::Node operation, int delta
) {
invalidPointerToDerefSource(allocation, pai, derefSource) and
flow(derefSource, derefSink) and
derefSinkToOperation(derefSink, pai, operation, description, delta)
exists(int deltaDerefSourceAndPai, int deltaDerefSinkAndDerefAddress |
invalidPointerToDerefSource(allocation, pai, derefSource, deltaDerefSourceAndPai) and
flow(derefSource, derefSink) and
derefSinkToOperation(derefSink, pai, operation, description, deltaDerefSourceAndPai,
deltaDerefSinkAndDerefAddress) and
delta = deltaDerefSourceAndPai + deltaDerefSinkAndDerefAddress
)
}

View File

@@ -372,8 +372,7 @@ private predicate analyzablePointerFieldAccess(PointerFieldAccess access) {
private predicate mk_PointerFieldAccess(HashCons qualifier, Field target, PointerFieldAccess access) {
analyzablePointerFieldAccess(access) and
target = access.getTarget() and
qualifier = hashCons(access.getQualifier().getFullyConverted()) and
not access instanceof ImplicitThisFieldAccess
qualifier = hashCons(access.getQualifier().getFullyConverted())
}
private predicate analyzableImplicitThisFieldAccess(ImplicitThisFieldAccess access) {

View File

@@ -197,11 +197,6 @@ svnchurn(
* C++ dbscheme
*/
extractor_version(
string codeql_version: string ref,
string frontend_version: string ref
)
@location = @location_stmt | @location_expr | @location_default ;
/**
@@ -617,14 +612,6 @@ case @builtintype.kind of
| 51 = @char8_t
| 52 = @float16 // _Float16
| 53 = @complex_float16 // _Complex _Float16
| 54 = @fp16 // __fp16
| 55 = @std_bfloat16 // __bf16
| 56 = @std_float16 // std::float16_t
| 57 = @complex_std_float32 // _Complex _Float32
| 58 = @complex_float32x // _Complex _Float32x
| 59 = @complex_std_float64 // _Complex _Float64
| 60 = @complex_float64x // _Complex _Float64x
| 61 = @complex_std_float128 // _Complex _Float128
;
builtintypes(
@@ -1334,16 +1321,11 @@ funbind(
| @assignxorexpr
| @assignlshiftexpr
| @assignrshiftexpr
;
@assign_pointer_expr = @assignpaddexpr
| @assignpaddexpr
| @assignpsubexpr
;
@assign_op_expr = @assign_arith_expr
| @assign_bitwise_expr
| @assign_pointer_expr
;
@assign_op_expr = @assign_arith_expr | @assign_bitwise_expr
@assign_expr = @assignexpr | @assign_op_expr | @blockassignexpr

File diff suppressed because it is too large Load Diff

View File

@@ -1,2 +0,0 @@
description: Introduce extractor version numbers
compatibility: full

View File

@@ -1,2 +0,0 @@
description: Introduce new floating-point types from C23 and C++23
compatibility: full

View File

@@ -1,2 +0,0 @@
description: Removed @assignpaddexpr and @assignpsubexpr from @assign_bitwise_expr
compatibility: full

View File

@@ -1,15 +1,3 @@
## 0.8.2
No user-facing changes.
## 0.8.1
### New Queries
* The query `cpp/redundant-null-check-simple` has been promoted to Code Scanning. The query finds cases where a pointer is compared to null after it has already been dereferenced. Such comparisons likely indicate a bug at the place where the pointer is dereferenced, or where the pointer is compared to null.
Note: This query was incorrectly noted as being promoted to Code Scanning in CodeQL version 2.14.6.
## 0.8.0
### Query Metadata Changes

View File

@@ -27,26 +27,16 @@ class ReturnStackAllocatedMemoryConfig extends MustFlowConfiguration {
ReturnStackAllocatedMemoryConfig() { this = "ReturnStackAllocatedMemoryConfig" }
override predicate isSource(Instruction source) {
exists(Function func |
// Holds if `source` is a node that represents the use of a stack variable
exists(VariableAddressInstruction var, Function func |
var = source and
func = source.getEnclosingFunction() and
var.getAstVariable() instanceof StackVariable and
// Pointer-to-member types aren't properly handled in the dbscheme.
not var.getResultType() instanceof PointerToMemberType and
// Rule out FPs caused by extraction errors.
not any(ErrorExpr e).getEnclosingFunction() = func and
not intentionallyReturnsStackPointer(func) and
func = source.getEnclosingFunction()
|
// `source` is an instruction that represents the use of a stack variable
exists(VariableAddressInstruction var |
var = source and
var.getAstVariable() instanceof StackVariable and
// Pointer-to-member types aren't properly handled in the dbscheme.
not var.getResultType() instanceof PointerToMemberType
)
or
// `source` is an instruction that represents the return value of a
// function that is known to return stack-allocated memory.
exists(Call call |
call.getTarget().hasGlobalName(["alloca", "strdupa", "strndupa", "_alloca", "_malloca"]) and
source.getUnconvertedResultExpression() = call
)
not intentionallyReturnsStackPointer(func)
)
}
@@ -95,10 +85,10 @@ class ReturnStackAllocatedMemoryConfig extends MustFlowConfiguration {
}
from
MustFlowPathNode source, MustFlowPathNode sink, Instruction instr,
MustFlowPathNode source, MustFlowPathNode sink, VariableAddressInstruction var,
ReturnStackAllocatedMemoryConfig conf
where
conf.hasFlowPath(pragma[only_bind_into](source), pragma[only_bind_into](sink)) and
source.getInstruction() = instr
source.getInstruction() = var
select sink.getInstruction(), source, sink, "May return stack-allocated memory from $@.",
instr.getAst(), instr.getAst().toString()
var.getAst(), var.getAst().toString()

View File

@@ -13,8 +13,7 @@
*/
import cpp
import semmle.code.cpp.ir.IR
import semmle.code.cpp.ir.dataflow.MustFlow
import semmle.code.cpp.controlflow.StackVariableReachability
/**
* Auxiliary predicate: Types that don't require initialization
@@ -34,6 +33,31 @@ predicate allocatedType(Type t) {
allocatedType(t.getUnspecifiedType())
}
/**
* A declaration of a local variable that leaves the
* variable uninitialized.
*/
DeclStmt declWithNoInit(LocalVariable v) {
result.getADeclaration() = v and
not exists(v.getInitializer()) and
/* The type of the variable is not stack-allocated. */
exists(Type t | t = v.getType() | not allocatedType(t))
}
class UninitialisedLocalReachability extends StackVariableReachability {
UninitialisedLocalReachability() { this = "UninitialisedLocal" }
override predicate isSource(ControlFlowNode node, StackVariable v) { node = declWithNoInit(v) }
override predicate isSink(ControlFlowNode node, StackVariable v) { useOfVarActual(v, node) }
override predicate isBarrier(ControlFlowNode node, StackVariable v) {
// only report the _first_ possibly uninitialized use
useOfVarActual(v, node) or
definitionBarrier(v, node)
}
}
pragma[noinline]
predicate containsInlineAssembly(Function f) { exists(AsmStmt s | s.getEnclosingFunction() = f) }
@@ -58,33 +82,8 @@ VariableAccess commonException() {
containsInlineAssembly(result.getEnclosingFunction())
}
predicate isSinkImpl(Instruction sink, VariableAccess va) {
exists(LoadInstruction load |
va = load.getUnconvertedResultExpression() and
not va = commonException() and
sink = load.getSourceValue()
)
}
class MustFlow extends MustFlowConfiguration {
MustFlow() { this = "MustFlow" }
override predicate isSource(Instruction source) {
source instanceof UninitializedInstruction and
exists(Type t | t = source.getResultType() | not allocatedType(t))
}
override predicate isSink(Operand sink) { isSinkImpl(sink.getDef(), _) }
override predicate allowInterproceduralFlow() { none() }
override predicate isBarrier(Instruction instr) { instr instanceof ChiInstruction }
}
from
VariableAccess va, LocalVariable v, MustFlow conf, MustFlowPathNode source, MustFlowPathNode sink
from UninitialisedLocalReachability r, LocalVariable v, VariableAccess va
where
conf.hasFlowPath(source, sink) and
isSinkImpl(sink.getInstruction(), va) and
v = va.getTarget()
r.reaches(_, v, va) and
not va = commonException()
select va, "The variable $@ may not be initialized at this access.", v, v.getName()

View File

@@ -14,47 +14,25 @@
import cpp
import semmle.code.cpp.security.Security
import semmle.code.cpp.security.FlowSources
import semmle.code.cpp.ir.dataflow.TaintTracking
import semmle.code.cpp.ir.IR
import Flow::PathGraph
import semmle.code.cpp.ir.dataflow.internal.DefaultTaintTrackingImpl
import TaintedWithPath
predicate isProcessOperationExplanation(DataFlow::Node arg, string processOperation) {
predicate isProcessOperationExplanation(Expr arg, string processOperation) {
exists(int processOperationArg, FunctionCall call |
isProcessOperationArgument(processOperation, processOperationArg) and
call.getTarget().getName() = processOperation and
call.getArgument(processOperationArg) = [arg.asExpr(), arg.asIndirectExpr()]
call.getArgument(processOperationArg) = arg
)
}
predicate isSource(FlowSource source, string sourceType) {
not source instanceof DataFlow::ExprNode and
sourceType = source.getSourceType()
class Configuration extends TaintTrackingConfiguration {
override predicate isSink(Element arg) { isProcessOperationExplanation(arg, _) }
}
module Config implements DataFlow::ConfigSig {
predicate isSource(DataFlow::Node node) { isSource(node, _) }
predicate isSink(DataFlow::Node node) { isProcessOperationExplanation(node, _) }
predicate isBarrier(DataFlow::Node node) {
isSink(node) and node.asExpr().getUnspecifiedType() instanceof ArithmeticType
or
node.asInstruction().(StoreInstruction).getResultType() instanceof ArithmeticType
}
}
module Flow = TaintTracking::Global<Config>;
from
string processOperation, string sourceType, DataFlow::Node source, DataFlow::Node sink,
Flow::PathNode sourceNode, Flow::PathNode sinkNode
from string processOperation, Expr arg, Expr source, PathNode sourceNode, PathNode sinkNode
where
source = sourceNode.getNode() and
sink = sinkNode.getNode() and
isSource(source, sourceType) and
isProcessOperationExplanation(sink, processOperation) and
Flow::flowPath(sourceNode, sinkNode)
select sink, sourceNode, sinkNode,
isProcessOperationExplanation(arg, processOperation) and
taintedWithPath(source, arg, sourceNode, sinkNode)
select arg, sourceNode, sinkNode,
"The value of this argument may come from $@ and is being passed to " + processOperation + ".",
source, sourceType
source, source.toString()

View File

@@ -15,10 +15,9 @@
*/
import semmle.code.cpp.security.BufferWrite
import semmle.code.cpp.security.FlowSources as FS
import semmle.code.cpp.dataflow.new.TaintTracking
import semmle.code.cpp.controlflow.IRGuards
import Flow::PathGraph
import semmle.code.cpp.security.Security
import semmle.code.cpp.ir.dataflow.internal.DefaultTaintTrackingImpl
import TaintedWithPath
/*
* --- Summary of CWE-120 alerts ---
@@ -48,54 +47,38 @@ predicate isUnboundedWrite(BufferWrite bw) {
not exists(bw.getMaxData(_)) // and we can't deduce an upper bound to the amount copied
}
/*
* predicate isMaybeUnboundedWrite(BufferWrite bw)
* {
* not bw.hasExplicitLimit() // has no explicit size limit
* and exists(bw.getMaxData()) // and we can deduce an upper bound to the amount copied
* and (not exists(getBufferSize(bw.getDest(), _))) // but we can't work out the size of the destination to be sure
* }
*/
/**
* Holds if `e` is a source buffer going into an unbounded write `bw` or a
* qualifier of (a qualifier of ...) such a source.
*/
predicate unboundedWriteSource(Expr e, BufferWrite bw, boolean qualifier) {
isUnboundedWrite(bw) and e = bw.getASource() and qualifier = false
predicate unboundedWriteSource(Expr e, BufferWrite bw) {
isUnboundedWrite(bw) and e = bw.getASource()
or
exists(FieldAccess fa | unboundedWriteSource(fa, bw, _) and e = fa.getQualifier()) and
qualifier = true
exists(FieldAccess fa | unboundedWriteSource(fa, bw) and e = fa.getQualifier())
}
predicate isSource(FS::FlowSource source, string sourceType) { source.getSourceType() = sourceType }
/*
* --- user input reach ---
*/
predicate isSink(DataFlow::Node sink, BufferWrite bw, boolean qualifier) {
unboundedWriteSource(sink.asIndirectExpr(), bw, qualifier)
or
// `gets` and `scanf` reads from stdin so there's no real input.
// The `BufferWrite` library models this as the call itself being
// the source. In this case we mark the output argument as being
// the sink so that we report a path where source = sink (because
// the same output argument is also included in `isSource`).
bw.getASource() = bw and
unboundedWriteSource(sink.asDefiningArgument(), bw, qualifier)
class Configuration extends TaintTrackingConfiguration {
override predicate isSink(Element tainted) { unboundedWriteSource(tainted, _) }
override predicate taintThroughGlobals() { any() }
}
predicate lessThanOrEqual(IRGuardCondition g, Expr e, boolean branch) {
exists(Operand left |
g.comparesLt(left, _, _, true, branch) or
g.comparesEq(left, _, _, true, branch)
|
left.getDef().getUnconvertedResultExpression() = e
)
}
module Config implements DataFlow::ConfigSig {
predicate isSource(DataFlow::Node source) { isSource(source, _) }
predicate isSink(DataFlow::Node sink) { isSink(sink, _, _) }
predicate isBarrierOut(DataFlow::Node node) { isSink(node, _, false) }
predicate isBarrier(DataFlow::Node node) {
// Block flow if the node is guarded by any <, <= or = operations.
node = DataFlow::BarrierGuard<lessThanOrEqual/3>::getABarrierNode()
}
}
module Flow = TaintTracking::Global<Config>;
/*
* --- put it together ---
*/
/*
* An unbounded write is, for example `strcpy(..., tainted)`. We're looking
@@ -104,20 +87,17 @@ module Flow = TaintTracking::Global<Config>;
*
* In the case of `gets` and `scanf`, where the source buffer is implicit, the
* `BufferWrite` library reports the source buffer to be the same as the
* destination buffer. So to report an alert on a pattern like:
* ```
* char s[32];
* gets(s);
* ```
* we define the sink as the node corresponding to the output argument of `gets`.
* This gives us a path where the source is equal to the sink.
* destination buffer. Since those destination-buffer arguments are also
* modeled in the taint-tracking library as being _sources_ of taint, they are
* in practice reported as being tainted because the `security.TaintTracking`
* library does not distinguish between taint going into an argument and out of
* an argument. Thus, we get the desired alerts.
*/
from BufferWrite bw, Flow::PathNode source, Flow::PathNode sink, string sourceType
from BufferWrite bw, Expr inputSource, Expr tainted, PathNode sourceNode, PathNode sinkNode
where
Flow::flowPath(source, sink) and
isSource(source.getNode(), sourceType) and
isSink(sink.getNode(), bw, _)
select bw, source, sink,
"This '" + bw.getBWDesc() + "' with input from $@ may overflow the destination.",
source.getNode(), sourceType
taintedWithPath(inputSource, tainted, sourceNode, sinkNode) and
unboundedWriteSource(tainted, bw)
select bw, sourceNode, sinkNode,
"This '" + bw.getBWDesc() + "' with input from $@ may overflow the destination.", inputSource,
inputSource.toString()

View File

@@ -0,0 +1,24 @@
#include <stdio.h>
char *copy;
void copyArgv(char **argv) {
copy = argv[1];
}
void printWrapper(char *str) {
printf(str);
}
int main(int argc, char **argv) {
copyArgv(argv);
// This should be avoided
printf(copy);
// This should be avoided too, because it has the same effect
printWrapper(copy);
// This is fine
printf("%s", copy);
}

View File

@@ -0,0 +1,36 @@
<!DOCTYPE qhelp PUBLIC
"-//Semmle//qhelp//EN"
"qhelp.dtd">
<qhelp>
<overview>
<p>The program uses input from the user, propagated via a global variable, as a format string for <code>printf</code> style functions.
This can lead to buffer overflows or data representation problems. An attacker can exploit this weakness to crash the program,
disclose information or even execute arbitrary code.</p>
<p>This rule only identifies inputs from the user that are transferred through global variables before being used in <code>printf</code> style functions.
Analyzing the flow of data through global variables is more prone to errors and so this rule may identify some examples of code where
the input is not really from the user. For example, when a global variable is set in two places, one that comes from the user and one that does not.
In this case we would mark all usages of the global variable as input from the user, but the input from the user may always came after the call to the
<code>printf</code> style functions.</p>
<p>The results of this rule should be considered alongside the related rule "Uncontrolled format string" which tracks the flow of the
values input by a user, excluding global variables, until the values are used as the format argument for a <code>printf</code> like function call.</p>
</overview>
<recommendation>
<p>Use constant expressions as the format strings. If you need to print a value from the user, use <code>printf("%s", value_from_user)</code>.</p>
</recommendation>
<example>
<sample src="UncontrolledFormatStringThroughGlobalVar.c" />
</example>
<references>
<li>CERT C Coding
Standard: <a href="https://www.securecoding.cert.org/confluence/display/c/FIO30-C.+Exclude+user+input+from+format+strings">FIO30-C. Exclude
user input from format strings</a>.</li>
</references>
</qhelp>

View File

@@ -0,0 +1,40 @@
/**
* @name Uncontrolled format string (through global variable)
* @description Using externally-controlled format strings in
* printf-style functions can lead to buffer overflows
* or data representation problems.
* @kind path-problem
* @problem.severity warning
* @security-severity 9.3
* @precision high
* @id cpp/tainted-format-string-through-global
* @tags reliability
* security
* external/cwe/cwe-134
*/
import cpp
import semmle.code.cpp.security.FunctionWithWrappers
import semmle.code.cpp.security.Security
import semmle.code.cpp.ir.dataflow.internal.DefaultTaintTrackingImpl
import TaintedWithPath
class Configuration extends TaintTrackingConfiguration {
override predicate isSink(Element tainted) {
exists(PrintfLikeFunction printf | printf.outermostWrapperFunctionCall(tainted, _))
}
override predicate taintThroughGlobals() { any() }
}
from
PrintfLikeFunction printf, Expr arg, PathNode sourceNode, PathNode sinkNode,
string printfFunction, Expr userValue, string cause
where
printf.outermostWrapperFunctionCall(arg, printfFunction) and
not taintedWithoutGlobals(arg) and
taintedWithPath(userValue, arg, sourceNode, sinkNode) and
isUserInput(userValue, cause)
select arg, sourceNode, sinkNode,
"The value of this argument may come from $@ and is being used as a formatting argument to " +
printfFunction + ".", userValue, cause

View File

@@ -14,13 +14,10 @@
import cpp
import semmle.code.cpp.security.Overflow
import semmle.code.cpp.dataflow.new.TaintTracking
import semmle.code.cpp.dataflow.new.DataFlow
import semmle.code.cpp.ir.IR
import semmle.code.cpp.controlflow.IRGuards as IRGuards
import semmle.code.cpp.security.FlowSources as FS
import semmle.code.cpp.security.Security
import semmle.code.cpp.ir.dataflow.internal.DefaultTaintTrackingImpl
import TaintedWithPath
import Bounded
import Flow::PathGraph
bindingset[op]
predicate missingGuard(Operation op, Expr e, string effect) {
@@ -31,90 +28,28 @@ predicate missingGuard(Operation op, Expr e, string effect) {
not e instanceof VariableAccess and effect = "overflow"
}
predicate isSource(FS::FlowSource source, string sourceType) { sourceType = source.getSourceType() }
predicate isSink(DataFlow::Node sink, Operation op, Expr e) {
e = sink.asExpr() and
missingGuard(op, e, _) and
op.getAnOperand() = e and
(
op instanceof UnaryArithmeticOperation or
op instanceof BinaryArithmeticOperation or
op instanceof AssignArithmeticOperation
)
}
predicate hasUpperBoundsCheck(Variable var) {
exists(RelationalOperation oper, VariableAccess access |
oper.getAnOperand() = access and
access.getTarget() = var and
// Comparing to 0 is not an upper bound check
not oper.getAnOperand().getValue() = "0"
)
}
predicate constantInstruction(Instruction instr) {
instr instanceof ConstantInstruction or
constantInstruction(instr.(UnaryInstruction).getUnary())
}
predicate readsVariable(LoadInstruction load, Variable var) {
load.getSourceAddress().(VariableAddressInstruction).getAstVariable() = var
}
predicate nodeIsBarrierEqualityCandidate(DataFlow::Node node, Operand access, Variable checkedVar) {
exists(Instruction instr | instr = node.asInstruction() |
readsVariable(instr, checkedVar) and
any(IRGuards::IRGuardCondition guard).ensuresEq(access, _, _, instr.getBlock(), true)
)
}
module Config implements DataFlow::ConfigSig {
predicate isSource(DataFlow::Node source) { isSource(source, _) }
predicate isSink(DataFlow::Node sink) { isSink(sink, _, _) }
predicate isBarrier(DataFlow::Node node) {
exists(StoreInstruction store | store = node.asInstruction() |
// Block flow to "likely small expressions"
bounded(store.getSourceValue().getUnconvertedResultExpression())
or
// Block flow to "small types"
store.getResultType().getUnspecifiedType().(IntegralType).getSize() <= 1
)
or
// Block flow if there's an upper bound check of the variable anywhere in the program
exists(Variable checkedVar, Instruction instr | instr = node.asInstruction() |
readsVariable(instr, checkedVar) and
hasUpperBoundsCheck(checkedVar)
)
or
// Block flow if the node is guarded by an equality check
exists(Variable checkedVar, Operand access |
nodeIsBarrierEqualityCandidate(node, access, checkedVar) and
readsVariable(access.getDef(), checkedVar)
)
or
// Block flow to any binary instruction whose operands are both non-constants.
exists(BinaryInstruction iTo |
iTo = node.asInstruction() and
not constantInstruction(iTo.getLeft()) and
not constantInstruction(iTo.getRight()) and
// propagate taint from either the pointer or the offset, regardless of constantness
not iTo instanceof PointerArithmeticInstruction
class Configuration extends TaintTrackingConfiguration {
override predicate isSink(Element e) {
exists(Operation op |
missingGuard(op, e, _) and
op.getAnOperand() = e
|
op instanceof UnaryArithmeticOperation or
op instanceof BinaryArithmeticOperation or
op instanceof AssignArithmeticOperation
)
}
override predicate isBarrier(Expr e) {
super.isBarrier(e) or bounded(e) or e.getUnspecifiedType().(IntegralType).getSize() <= 1
}
}
module Flow = TaintTracking::Global<Config>;
from
Expr e, string effect, Flow::PathNode source, Flow::PathNode sink, Operation op, string sourceType
from Expr origin, Expr e, string effect, PathNode sourceNode, PathNode sinkNode, Operation op
where
Flow::flowPath(source, sink) and
isSource(source.getNode(), sourceType) and
isSink(sink.getNode(), op, e) and
taintedWithPath(origin, e, sourceNode, sinkNode) and
op.getAnOperand() = e and
missingGuard(op, e, effect)
select e, source, sink,
select e, sourceNode, sinkNode,
"$@ flows to an operand of an arithmetic expression, potentially causing an " + effect + ".",
source, sourceType
origin, "User-provided value"

View File

@@ -8,6 +8,7 @@
* @id cpp/invalid-pointer-deref
* @tags reliability
* security
* experimental
* external/cwe/cwe-119
* external/cwe/cwe-125
* external/cwe/cwe-193

View File

@@ -15,7 +15,6 @@
import cpp
import semmle.code.cpp.ir.dataflow.TaintTracking
import semmle.code.cpp.models.interfaces.FlowSource
import semmle.code.cpp.models.implementations.Memset
import ExposedSystemData::PathGraph
import SystemData
@@ -29,10 +28,6 @@ module ExposedSystemDataConfig implements DataFlow::ConfigSig {
fc.getArgument(arg).getAChild*() = sink.asIndirectExpr()
)
}
predicate isBarrier(DataFlow::Node node) {
node.asIndirectArgument() = any(MemsetFunction func).getACallToThisFunction().getAnArgument()
}
}
module ExposedSystemData = TaintTracking::Global<ExposedSystemDataConfig>;

View File

@@ -28,7 +28,6 @@ import cpp
import semmle.code.cpp.ir.dataflow.TaintTracking
import semmle.code.cpp.models.interfaces.FlowSource
import semmle.code.cpp.security.OutputWrite
import semmle.code.cpp.models.implementations.Memset
import PotentiallyExposedSystemData::PathGraph
import SystemData
@@ -50,10 +49,6 @@ module PotentiallyExposedSystemDataConfig implements DataFlow::ConfigSig {
else child = sink.asExpr()
)
}
predicate isBarrier(DataFlow::Node node) {
node.asIndirectArgument() = any(MemsetFunction func).getACallToThisFunction().getAnArgument()
}
}
module PotentiallyExposedSystemData = TaintTracking::Global<PotentiallyExposedSystemDataConfig>;

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@@ -4,7 +4,6 @@
* @description The total number of lines of C/C++ code across all files, including system headers, libraries, and auto-generated files. This is a useful metric of the size of a database. For all files that were seen during the build, this query counts the lines of code, excluding whitespace or comments.
* @kind metric
* @tags summary
* telemetry
*/
import cpp

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@@ -1,7 +1,6 @@
## 0.8.1
### New Queries
---
category: newQuery
---
* The query `cpp/redundant-null-check-simple` has been promoted to Code Scanning. The query finds cases where a pointer is compared to null after it has already been dereferenced. Such comparisons likely indicate a bug at the place where the pointer is dereferenced, or where the pointer is compared to null.
Note: This query was incorrectly noted as being promoted to Code Scanning in CodeQL version 2.14.6.

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