Bounds-check BufferView::read - #352
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asmaloney merged 1 commit intoAug 12, 2026
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Passing a short (< 1024 byte) memory buffer to CheckedFile causes an out-of-bounds read and ASAN failure. CheckedFile::readPhysicalPage always requests a full physicalPageSize regardless of how many bytes remain, and BufferView::read copied that many bytes without comparing against streamSize_. The file-backed branch already refuses a short read; this makes the buffer-backed branch behave the same way. The check is written as ( count > streamSize_ - start ) rather than ( start + count > streamSize_ ) so it cannot itself overflow.
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Thanks for this (and our conversation). I have a test written up already (based on yours) since I implemented the other file length fix I mentioned. I will push that separately. (I also fixed the failing tests when the test files aren't present.) I'll also handle the change log later (I tend to do that in batches). |
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Fixed by #352 Co-authored-by: spartan <39662153+spartan8806@users.noreply.github.com>
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asmaloney
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) Fixed by #352 Co-authored-by: spartan <39662153+spartan8806@users.noreply.github.com>
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Passing a short (< 1024 byte) memory buffer to
CheckedFilecauses an out-of-bounds read and ASAN failure.CheckedFile::readPhysicalPage()always requests a fullphysicalPageSizeregardless of how many bytes actually remain, andBufferView::read()copied that many bytes without comparing againststreamSize_. The file-backed branch immediately below it already refuses a short read — this makes the buffer-backed branch behave the same way.The check is written as
count > streamSize_ - startrather thanstart + count > streamSize_so it can't itself overflow.Verified against a clean checkout of
master:heap-buffer-overflow,READ of size 1, atCheckedFile.cpp:177E57Exceptionunder bothChecksumAllandChecksumNone, exit 0, no ASAN reportHappy to add a CHANGELOG entry under 3.4.0 → Fixed once this has a PR number, and a regression test that feeds a short buffer to the memory constructor — just say the word and I'll push either to this branch.