Rust: regenerate models #19748
Rust: regenerate models #19748
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Models are regenerated with the fix from #19744 which corrects the order of generation.
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Pull Request Overview
Regenerates Rust models after correcting the order of generation (CodeQL PR 19744) and updates the CWE-770 test suite to account for one newly introduced false positive.
- Annotates the
shrinkcall inmain.rsas a spurious alert. - Inserts corresponding expected entries in the test’s
.expectedfile.
Reviewed Changes
Copilot reviewed 20 out of 20 changed files in this pull request and generated no comments.
| File | Description |
|---|---|
| rust/ql/test/query-tests/security/CWE-770/main.rs | Added // $ SPURIOUS comment on the shrink call to mark a FP. |
| rust/ql/test/query-tests/security/CWE-770/UncontrolledAllocationSize.expected | Added new expected lines for the spurious shrink alert and re-numbered model sinks/summaries. |
| @@ -210,7 +210,7 @@ unsafe fn test_system_alloc(v: usize) { | |||
| let _ = std::alloc::System.grow_zeroed(m4, l4, l2).unwrap(); // $ Alert[rust/uncontrolled-allocation-size]=arg1 | |||
| } | |||
| } else { | |||
| let _ = std::alloc::System.shrink(m4, l4, l2).unwrap(); | |||
| let _ = std::alloc::System.shrink(m4, l4, l2).unwrap(); // $ SPURIOUS: Alert[rust/uncontrolled-allocation-size]=arg1 - FP | |||
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I think the model generator is right to generate flow for this, shrink is causing an allocation to happen and the new size l2 is user controlled. The reason this is a FP is because we know a shrink can only reduce the size of the allocation so the allocation is bounded - this can't be the source of a problem.
I think the right answer is to introduce a barrier. I can do this as follow-up to your PR.
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well, reading https://doc.rust-lang.org/beta/std/alloc/trait.Allocator.html#safety-4 I can't decide whether we can count on shrink actually shrinking, considering that the constraint of l2's size being smaller that l4's one is actually a safety contract to be guaranteed by the user.
However apart from that, we should know that l2 has size v, and that v < 10 here, which means we aren't really unconstrained in any case here. Or is this too much for the current implementation of the analysis? Are we doing some kind of range analysis?
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We don't have range analysis, we do have barrier guards and in fact the query is using them. However in this case the check on v is after the std::alloc::Layout has been created from it, so we don't notice the guard applies to the layout. I'll see if I can easily address this...
Models are regenerated with the fix from #19744 which corrects the order of generation.
Notice the one new FP in the tests though.