Enhance cpp/overflow-calculated
- detect out-of-bounds write caused by passing the buffer size in bytes (using sizeof) instead of the number of elements to wcsftime, allowing the function to overrun the allocated buffer.
#19722
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This pull request improves the detection of buffer overflow issues in the
OverflowCalculated.ql
query.Improvements to buffer overflow detection:
Enhanced query description: The description of the query has been updated to include scenarios involving incorrect size calculations for wide character functions, improving clarity and scope. Additionally, the precision level was set to "medium" to better reflect the query's behavior. (
cpp/ql/src/Critical/OverflowCalculated.ql
, cpp/ql/src/Critical/OverflowCalculated.qlL2-R5)New predicate for wide character size issues: Added the
wideCharSizeofProblem
predicate to detect cases where thesizeof
operator is incorrectly used withwcsftime
, leading to potential buffer overflows. The predicate checks for miscalculations in thecount
parameter by ensuring that the size is expressed in terms ofwchar_t
elements rather than bytes. (cpp/ql/src/Critical/OverflowCalculated.ql
, cpp/ql/src/Critical/OverflowCalculated.qlR44-R64)Updated query logic: Modified the
where
clause in the query to include the newwideCharSizeofProblem
predicate, enabling the detection of both traditional space problems and wide character size issues. (cpp/ql/src/Critical/OverflowCalculated.ql
, cpp/ql/src/Critical/OverflowCalculated.qlR44-R64)