CVE-2026-72478fs/ntfs3: add bounds check to run_get_highest_vcn()

Official description

In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: add bounds check to run_get_highest_vcn() run_get_highest_vcn() parses a packed NTFS mapping-pairs buffer without any length bound, relying solely on a 0x00 terminator to stop. A crafted $LogFile UpdateMappingPairs record whose embedded attribute contains mapping-pairs runs without a terminator causes the function to read past the slab allocation, triggering a KASAN slab-out-of-bounds read on mount. The sibling function run_unpack() received an analogous bounds-check in commit b62567bca474 ("ntfs3: add buffer boundary checks to run_unpack()"), but run_get_highest_vcn() was missed. Take a run_buf_size parameter and reject any run header whose payload would extend past the buffer end, mirroring the pattern used by run_unpack(). The caller in fslog.c passes the remaining attribute bytes after the mapping-pairs offset. KASAN report (on mainline v7.1 merge window HEAD): BUG: KASAN: slab-out-of-bounds in run_get_highest_vcn+0x3c0/0x410 Read of size 1 at addr ffff88800e2d5400 by task mount/72 Call Trace: run_get_highest_vcn+0x3c0/0x410 do_action.isra.0+0x3ba8/0x7b50 log_replay+0x9ddd/0x10200 ntfs_loadlog_and_replay+0x4ad/0x610 ntfs_fill_super+0x214a/0x4540

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/c69b9003332917b652175d5fa9d84158c5ed8617
• https://git.kernel.org/stable/c/8afc24a884aff6a6f08028bd779ee65c40054455
• https://git.kernel.org/stable/c/c23083b472a720c3f60b147db05b25b751c7c1bf
• https://git.kernel.org/stable/c/a31893206588374d7d16fad387189d8165c7efd3
• https://git.kernel.org/stable/c/41081202eb823f5b27ff164b12010b24428100ad
• https://git.kernel.org/stable/c/bb11485a87fbb2254b62cfed630b699d50e57da8