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C++: Fix strtok model for indirections #14587

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Merged
MathiasVP merged 2 commits into from
Oct 25, 2023
Merged

C++: Fix strtok model for indirections #14587

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f54379d
C++: Add failing test.
MathiasVP Oct 25, 2023
032572b
C++: Fix 'strtok' model.
MathiasVP Oct 25, 2023
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2 changes: 2 additions & 0 deletions cpp/ql/lib/semmle/code/cpp/models/implementations/Strtok.qll
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Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,8 @@ 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() }
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7 changes: 7 additions & 0 deletions cpp/ql/test/library-tests/dataflow/taint-tests/localTaint.expected
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Expand Up @@ -6622,6 +6622,13 @@ WARNING: Module TaintTracking has been deprecated and may be removed in future (
| taint.cpp:711:13:711:13 | s | taint.cpp:711:2:711:8 | call to strncpy | TAINT |
| taint.cpp:711:13:711:13 | s | taint.cpp:711:10:711:10 | ref arg d | TAINT |
| taint.cpp:712:7:712:7 | ref arg d | taint.cpp:709:25:709:25 | d | |
| taint.cpp:718:17:718:31 | call to indirect_source | taint.cpp:720:27:720:32 | source | |
| taint.cpp:719:22:719:29 | ,.-;:_ | taint.cpp:720:35:720:39 | delim | |
| taint.cpp:719:22:719:29 | ,.-;:_ | taint.cpp:722:8:722:12 | delim | |
| taint.cpp:720:20:720:25 | call to strtok | taint.cpp:721:8:721:16 | tokenized | |
| taint.cpp:720:27:720:32 | source | taint.cpp:720:20:720:25 | call to strtok | TAINT |
| taint.cpp:721:8:721:16 | tokenized | taint.cpp:721:7:721:16 | * ... | TAINT |
| taint.cpp:722:8:722:12 | delim | taint.cpp:722:7:722:12 | * ... | TAINT |
| vector.cpp:16:43:16:49 | source1 | vector.cpp:17:26:17:32 | source1 | |
| vector.cpp:16:43:16:49 | source1 | vector.cpp:31:38:31:44 | source1 | |
| vector.cpp:17:21:17:33 | call to vector | vector.cpp:19:14:19:14 | v | |
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10 changes: 10 additions & 0 deletions cpp/ql/test/library-tests/dataflow/taint-tests/taint.cpp
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Expand Up @@ -710,4 +710,14 @@ void test_strncpy(char* d, char* s) {
argument_source(s);
strncpy(d, s, 16);
sink(d); // $ ast ir
}

char* indirect_source();

void test_strtok_indirect() {
char *source = indirect_source();
const char* delim = ",.-;:_";
char* tokenized = strtok(source, delim);
sink(*tokenized); // $ ir MISSING: ast
sink(*delim);
}