π Fix integer overflow in malloc alignment calculation#20
π Fix integer overflow in malloc alignment calculation#20undivisible wants to merge 1 commit into
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Added bounds checking to `malloc` to prevent `n + 7` from overflowing when `n` is very large, which could result in an undersized allocation. Also added corresponding test cases to `libc_selftest`. 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: The
β οΈ Risk: If
mallocfunction inkernel/libc.inhad an integer overflow vulnerability in its alignment calculation.nwas very large,n+7could overflow to a small or negative value, resulting in a small allocation when a large one was requested, potentially leading to heap corruption or out-of-bounds writes.π‘οΈ Solution: Added a bounds check ensuring that
n >= 0andn <= 0x7FFFFFFFFFFFFFF0. If the bounds are violated,mallocsafely returns0(NULL). Added tests tolibc_selftestto ensure negative values and values causing overflow return 0.PR created automatically by Jules for task 18437292978828511348 started by @undivisible