Add overflow checks before calling memory allocators
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- Python
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Description
Bug report
Bug description:
From https://github.com/capi-workgroup/decisions/issues/50#issuecomment-2522706899 and https://github.com/capi-workgroup/decisions/issues/50#issuecomment-2514640058.
Some calls to the PyMem_* API uses an arithmetic operation on the size, which could make the requested length overflow. The checks in the corresponding functions would not be relevant since the inputs already overflowed.
See https://github.com/python/cpython/pull/127686#issuecomment-2523699454 for the future of this issue.
CPython versions tested on:
CPython main branch
Operating systems tested on:
No response
Linked PRs
- gh-153489
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reviewing the PyMem_* allocator calls on the CPython main branch and the linked discussion in gh-153489. Trace each size arithmetic operation before allocation, then verify that overflow cases are handled before the allocator is called.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- c
- Domain
- backend
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 25/100