π Fix out-of-bounds read in realloc#21
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Modified `malloc` to prepend an 8-byte header storing the requested allocation size. `realloc` now utilizes this header to determine the original size and ensure it only copies up to `min(old_size, new_size)` bytes. This prevents out-of-bounds reads into uninitialized or adjacent memory. Added missing assertions in `libc_selftest` to test the new functionality. Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>
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- Fix stray brace in kernel-root.in and remove dead thr_exit return - Add heap/obj_arena bounds checks (PRs #30, #26) - Harden malloc/calloc/realloc; replace strcpy with strlcpy; remove strcat (PRs #20, #18, #21, #28, #15) - Split nvme_pci_init, restore e1000_rx_poll, use FS_MAX_FILES constants (PRs #14, #17, #16) - Refresh context.md ponytail index after service-wrapper deletion
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Changes applied directly on main (rebased past shell.in extraction and service-wrapper deletion). Used panic() instead of unreachable()/assert() where the PRs referenced undefined helpers. |
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Merged to main in 22933b8. Changes applied directly on main (rebased past shell.in extraction and service-wrapper deletion). Used panic() instead of unreachable()/assert() where the PRs referenced undefined helpers. |
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π― What: An out-of-bounds read vulnerability in
β οΈ Risk: This could lead to sensitive data exposure by copying uninitialized or adjacent memory into the new buffer and potentially out-of-bounds memory accesses.
reallocwas identified where it forcefully readnbytes from the old pointer regardless of its original allocation size.π‘οΈ Solution:
mallocwas updated to allocate an extra 8 bytes and store the size of the allocation in a header.reallocnow reads this header to properly bound thememcpyto the minimum of the old and new allocation sizes.reallocwas also improved to handlep == 0andn == 0effectively. Included new automated tests inlibc_selftest.PR created automatically by Jules for task 8489064097905049913 started by @undivisible