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Fix 11461: arrayIndexOutOfBounds false positive (#4686)

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Paul Fultz II 2023-01-07 15:09:17 -06:00 committed by GitHub
parent a09667a6d9
commit 6020feb271
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2 changed files with 17 additions and 0 deletions
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3
lib/valueflow.cpp
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@ -9197,6 +9197,9 @@ static std::vector<ValueFlow::Value> isOutOfBoundsImpl(const ValueFlow::Value& s
return {}; return {};
if (size.bound == ValueFlow::Value::Bound::Lower) if (size.bound == ValueFlow::Value::Bound::Lower)
return {}; return {};
// Checking for underflow doesnt mean it could be out of bounds
if (indexValue->intvalue == 0)
return {};
ValueFlow::Value value = inferCondition(">=", indexTok, indexValue->intvalue); ValueFlow::Value value = inferCondition(">=", indexTok, indexValue->intvalue);
if (!value.isKnown()) if (!value.isKnown())
return {}; return {};

14
test/testbufferoverrun.cpp
View File

@ -195,6 +195,7 @@ private:
TEST_CASE(array_index_68); // #6655 TEST_CASE(array_index_68); // #6655
TEST_CASE(array_index_69); // #6370 TEST_CASE(array_index_69); // #6370
TEST_CASE(array_index_70); // #11355 TEST_CASE(array_index_70); // #11355
TEST_CASE(array_index_71); // #11461
TEST_CASE(array_index_multidim); TEST_CASE(array_index_multidim);
TEST_CASE(array_index_switch_in_for); TEST_CASE(array_index_switch_in_for);
TEST_CASE(array_index_for_in_for); // FP: #2634 TEST_CASE(array_index_for_in_for); // FP: #2634
@ -1912,6 +1913,19 @@ private:
ASSERT_EQUALS("[test.cpp:3]: (error) Array 'a[5]' accessed at index 5, which is out of bounds.\n", errout.str()); ASSERT_EQUALS("[test.cpp:3]: (error) Array 'a[5]' accessed at index 5, which is out of bounds.\n", errout.str());
} }
// #11461
void array_index_71()
{
check("unsigned int f(unsigned int Idx) {\n"
" if (Idx < 64)\n"
" return 0;\n"
" Idx -= 64;\n"
" int arr[64] = { 0 };\n"
" return arr[Idx];\n"
"}\n");
ASSERT_EQUALS("", errout.str());
}
void array_index_multidim() { void array_index_multidim() {
check("void f()\n" check("void f()\n"
"{\n" "{\n"