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MathiasVPMathiasVP
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Merge pull request #17034 from MathiasVP/more-alias-and-side-effect-models
C++: Add more alias and side effect models
2 parents 5a39610 + 3f5b4a8 commit 032ae9e

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14 files changed

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-1052
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14 files changed

+2299
-1052
lines changed

‎cpp/ql/lib/semmle/code/cpp/models/Models.qll‎

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Original file line numberDiff line numberDiff line change
@@ -27,6 +27,11 @@ private import implementations.StdPair
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private import implementations.StdMap
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private import implementations.StdSet
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private import implementations.StdString
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private import implementations.StdFunction
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private import implementations.StdException
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private import implementations.StdAllocator
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private import implementations.StdAlgorithm
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private import implementations.StdMath
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private import implementations.Swap
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private import implementations.GetDelim
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private import implementations.SmartPointer

‎cpp/ql/lib/semmle/code/cpp/models/implementations/Iterator.qll‎

Lines changed: 62 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -86,6 +86,41 @@ private class StdIterator extends Iterator, Class {
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override Type getValueType() { result = this.getTemplateArgument(1).(Type).getUnderlyingType() }
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}
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private class StdReverseIterator extends Iterator, Class {
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StdReverseIterator() { this.hasQualifiedName(["std", "bsl"], "reverse_iterator") }
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override Type getValueType() { result = this.getTemplateArgument(1).(Type).getUnderlyingType() }
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}
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private class StdIstreamBufIterator extends Iterator, Class {
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StdIstreamBufIterator() { this.hasQualifiedName(["std", "bsl"], "istreambuf_iterator") }
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override Type getValueType() { result = this.getTemplateArgument(1).(Type).getUnderlyingType() }
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}
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private class StdIstreambufIteratorConstructor extends Constructor, SideEffectFunction,
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AliasFunction
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{
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StdIstreambufIteratorConstructor() { this.getDeclaringType() instanceof StdIstreamBufIterator }
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override predicate parameterNeverEscapes(int index) { index = -1 }
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override predicate parameterEscapesOnlyViaReturn(int index) { none() }
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override predicate hasOnlySpecificReadSideEffects() { any() }
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override predicate hasOnlySpecificWriteSideEffects() { any() }
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override predicate hasSpecificWriteSideEffect(ParameterIndex i, boolean buffer, boolean mustWrite) {
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i = -1 and buffer = false and mustWrite = true
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}
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override predicate hasSpecificReadSideEffect(ParameterIndex i, boolean buffer) {
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this.getParameter(i).getUnspecifiedType() instanceof ReferenceType and
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buffer = false
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}
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}
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/**
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* Gets the `FunctionInput` corresponding to an iterator parameter to
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* user-defined operator `op`, at `index`.
@@ -579,31 +614,51 @@ private class IteratorAssignmentMemberOperatorModel extends IteratorAssignmentMe
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override predicate parameterEscapesOnlyViaReturn(int index) { index = -1 }
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}
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private string beginName() {
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result = ["begin", "cbegin", "rbegin", "crbegin", "before_begin", "cbefore_begin"]
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}
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/**
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* A `begin` member function, or a related function, that returns an iterator.
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*/
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class BeginFunction extends MemberFunction {
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class BeginFunction extends Function {
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BeginFunction() {
587-
this.hasName(["begin", "cbegin", "rbegin", "crbegin", "before_begin", "cbefore_begin"]) and
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this.getType().getUnspecifiedType() instanceof Iterator
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this.getUnspecifiedType() instanceof Iterator and
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(
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this.hasName(beginName()) and
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this instanceof MemberFunction
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or
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this.hasGlobalOrStdOrBslName(beginName()) and
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not this instanceof MemberFunction and
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this.getNumberOfParameters() = 1
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)
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}
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}
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private string endName() { result = ["end", "cend", "rend", "crend"] }
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/**
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* An `end` member function, or a related function, that returns an iterator.
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*/
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class EndFunction extends MemberFunction {
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class EndFunction extends Function {
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EndFunction() {
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this.hasName(["end", "cend", "rend", "crend"]) and
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this.getType().getUnspecifiedType() instanceof Iterator
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this.getUnspecifiedType() instanceof Iterator and
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(
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this.hasName(endName()) and
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this instanceof MemberFunction
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or
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this.hasGlobalOrStdOrBslName(endName()) and
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this instanceof MemberFunction and
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this.getNumberOfParameters() = 1
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)
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}
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}
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602657
/**
603658
* A `begin` or `end` member function, or a related member function, that
604659
* returns an iterator.
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*/
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class BeginOrEndFunction extends MemberFunction {
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class BeginOrEndFunction extends Function {
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BeginOrEndFunction() {
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this instanceof BeginFunction or
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this instanceof EndFunction

‎cpp/ql/lib/semmle/code/cpp/models/implementations/Printf.qll‎

Lines changed: 22 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -7,6 +7,7 @@
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import semmle.code.cpp.models.interfaces.FormattingFunction
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import semmle.code.cpp.models.interfaces.Alias
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import semmle.code.cpp.models.interfaces.SideEffect
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/**
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* The standard functions `printf`, `wprintf` and their glib variants.
@@ -96,7 +97,7 @@ private class Sprintf extends FormattingFunction {
9697
/**
9798
* Implements `Snprintf`.
9899
*/
99-
private class SnprintfImpl extends Snprintf {
100+
private class SnprintfImpl extends Snprintf, AliasFunction, SideEffectFunction {
100101
SnprintfImpl() {
101102
this instanceof TopLevelFunction and
102103
(
@@ -143,6 +144,26 @@ private class SnprintfImpl extends Snprintf {
143144
}
144145

145146
override int getSizeParameterIndex() { result = 1 }
147+
148+
override predicate parameterNeverEscapes(int index) {
149+
// We don't know how many parameters are passed to the function since it's varargs, but they also don't escape.
150+
index = this.getFormatParameterIndex()
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}
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override predicate parameterEscapesOnlyViaReturn(int index) { none() }
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override predicate hasOnlySpecificReadSideEffects() { any() }
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override predicate hasOnlySpecificWriteSideEffects() { any() }
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override predicate hasSpecificWriteSideEffect(ParameterIndex i, boolean buffer, boolean mustWrite) {
160+
i = this.getOutputParameterIndex(false) and buffer = true and mustWrite = false
161+
}
162+
163+
override predicate hasSpecificReadSideEffect(ParameterIndex i, boolean buffer) {
164+
// We don't know how many parameters are passed to the function since it's varargs, but they also have read side effects.
165+
i = this.getFormatParameterIndex() and buffer = true
166+
}
146167
}
147168

148169
/**

‎cpp/ql/lib/semmle/code/cpp/models/implementations/StdAlgorithm.qll‎

Lines changed: 115 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,115 @@
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/**
2+
* Provides models for C++ functions from the `algorithms` header.
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*/
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5+
import semmle.code.cpp.models.interfaces.Taint
6+
import semmle.code.cpp.models.interfaces.DataFlow
7+
import semmle.code.cpp.models.interfaces.Iterator
8+
import semmle.code.cpp.models.interfaces.SideEffect
9+
import semmle.code.cpp.models.interfaces.Alias
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11+
private class StdPartialSort extends Function, SideEffectFunction, AliasFunction {
12+
StdPartialSort() { this.hasGlobalOrStdName("partial_sort") }
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14+
override predicate hasOnlySpecificReadSideEffects() { any() }
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override predicate hasOnlySpecificWriteSideEffects() { any() }
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override predicate hasSpecificWriteSideEffect(ParameterIndex i, boolean buffer, boolean mustWrite) {
19+
i = this.getAnIteratorParameterIndex() and buffer = true and mustWrite = false
20+
}
21+
22+
override predicate hasSpecificReadSideEffect(ParameterIndex i, boolean buffer) {
23+
i = this.getAnIteratorParameterIndex() and
24+
buffer = true and
25+
this.getParameter(i).getUnspecifiedType() instanceof ReferenceType and
26+
buffer = false
27+
}
28+
29+
private int getAnIteratorParameterIndex() {
30+
this.getParameter(result).getUnspecifiedType() instanceof Iterator
31+
}
32+
33+
override predicate parameterNeverEscapes(int index) {
34+
index = this.getAnIteratorParameterIndex()
35+
or
36+
this.getParameter(index).getUnspecifiedType() instanceof ReferenceType
37+
}
38+
39+
override predicate parameterEscapesOnlyViaReturn(int index) { none() }
40+
}
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42+
private class StdSortHeap extends Function, SideEffectFunction, AliasFunction {
43+
StdSortHeap() { this.hasGlobalOrStdName("sort_heap") }
44+
45+
override predicate hasOnlySpecificReadSideEffects() { any() }
46+
47+
override predicate hasOnlySpecificWriteSideEffects() { any() }
48+
49+
override predicate hasSpecificWriteSideEffect(ParameterIndex i, boolean buffer, boolean mustWrite) {
50+
i = this.getAnIteratorParameterIndex() and buffer = true and mustWrite = false
51+
}
52+
53+
override predicate hasSpecificReadSideEffect(ParameterIndex i, boolean buffer) {
54+
i = this.getAnIteratorParameterIndex() and
55+
buffer = true
56+
}
57+
58+
private int getAnIteratorParameterIndex() {
59+
this.getParameter(result).getUnspecifiedType() instanceof Iterator
60+
}
61+
62+
override predicate parameterNeverEscapes(int index) { index = this.getAnIteratorParameterIndex() }
63+
64+
override predicate parameterEscapesOnlyViaReturn(int index) { none() }
65+
}
66+
67+
private class StdGenerateN extends Function, SideEffectFunction, AliasFunction {
68+
StdGenerateN() { this.hasGlobalOrStdName("generate_n") }
69+
70+
override predicate hasOnlySpecificReadSideEffects() { any() }
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72+
override predicate hasOnlySpecificWriteSideEffects() { any() }
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override predicate hasSpecificWriteSideEffect(ParameterIndex i, boolean buffer, boolean mustWrite) {
75+
i = this.getAnIteratorParameterIndex() and buffer = true and mustWrite = false
76+
}
77+
78+
override predicate hasSpecificReadSideEffect(ParameterIndex i, boolean buffer) {
79+
this.getParameter(i).getUnspecifiedType() instanceof ReferenceType and buffer = false
80+
}
81+
82+
private int getAnIteratorParameterIndex() {
83+
this.getParameter(result).getUnspecifiedType() instanceof Iterator
84+
}
85+
86+
override predicate parameterNeverEscapes(int index) { index = this.getAnIteratorParameterIndex() }
87+
88+
override predicate parameterEscapesOnlyViaReturn(int index) { none() }
89+
}
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91+
private class StdFindIfOrIfNot extends Function, SideEffectFunction, AliasFunction {
92+
StdFindIfOrIfNot() { this.hasGlobalOrStdName(["find_if", "find_if_not"]) }
93+
94+
override predicate hasOnlySpecificReadSideEffects() { any() }
95+
96+
override predicate hasOnlySpecificWriteSideEffects() { any() }
97+
98+
override predicate hasSpecificReadSideEffect(ParameterIndex i, boolean buffer) {
99+
i = this.getAnIteratorParameterIndex() and buffer = true
100+
or
101+
this.getParameter(i).getUnspecifiedType() instanceof ReferenceType and buffer = false
102+
}
103+
104+
private int getAnIteratorParameterIndex() {
105+
this.getParameter(result).getUnspecifiedType() instanceof Iterator
106+
}
107+
108+
override predicate parameterNeverEscapes(int index) {
109+
this.getParameter(index).getUnspecifiedType() instanceof ReferenceType
110+
}
111+
112+
override predicate parameterEscapesOnlyViaReturn(int index) {
113+
index = this.getAnIteratorParameterIndex()
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}
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}

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