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C++: fix equality refinement in new range analysis #13226

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Merged
MathiasVP merged 4 commits into from
May 24, 2023
Merged

C++: fix equality refinement in new range analysis #13226

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6a997ab
C++: fix equality refinement in new range analysis
May 22, 2023
681cc4c
C++: add neq refinement test for range analysis
May 22, 2023
86ab960
C++: add test comments
May 23, 2023
7404bd9
Merge branch 'main' into rdmarsh2/cpp/cobo-neq-refinement
May 24, 2023
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2 changes: 1 addition & 1 deletion ...l/lib/semmle/code/cpp/rangeanalysis/new/internal/semantic/analysis/RangeAnalysisStage.qll
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Expand Up @@ -729,7 +729,7 @@ module RangeStage<
) {
exists(SemExpr e, D::Delta d1, D::Delta d2 |
unequalFlowStepIntegralSsa(v, pos, e, d1, reason) and
boundedUpper(e, b, d1) and
boundedUpper(e, b, d2) and
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@MathiasVP MathiasVP May 19, 2023

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Would it be possible to add a range analysis library-test for this as well? That would also help make this commit independent of the other commits.

boundedLower(e, b, d2) and
delta = D::fromFloat(D::toFloat(d1) + D::toFloat(d2))
)
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33 changes: 33 additions & 0 deletions cpp/ql/test/experimental/query-tests/Security/CWE/CWE-193/constant-size/test.cpp
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Expand Up @@ -78,3 +78,36 @@ void testInterproc(BigArray *arr) {

addToPointerAndAssign(arr->buf);
}

void testEqRefinement() {
int arr[MAX_SIZE];

for(int i = 0; i <= MAX_SIZE; i++) {
if(i != MAX_SIZE) {
arr[i] = 0; // GOOD
}
}
}

void testEqRefinement2() {
int arr[MAX_SIZE];

int n = 0;

for(int i = 0; i <= MAX_SIZE; i++) {
if(n == 0) {
if(i == MAX_SIZE) {
break;
}
n = arr[i]; // GOOD
continue;
}

if (i == MAX_SIZE || n != arr[i]) {
if (i == MAX_SIZE) {
break;
}
n = arr[i]; // GOOD
}
}
}
11 changes: 11 additions & 0 deletions cpp/ql/test/library-tests/ir/range-analysis/test.cpp
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Expand Up @@ -59,3 +59,14 @@
range(i); // $ range=>=0 SPURIOUS: range="<=call to f3_get-1" range="<=call to f3_get-2"
}
}

int f4(int x) {
for (int i = 0; i <= 100; i++) {
range(i); // $ range=<=100 range=>=0
if(i == 100) {
range(i); // $ range===100
} else {
range(i); // $ range=<=99 range=>=0
}
}
}