CVE-2024-39276
In the Linux kernel, the following vulnerability has been resolved: ext4: fix mb_cache_entry's e_refcnt leak in ext4_xattr_block_cache_find() Syzbot reports a warning as follows: ============================================ WARNING: CPU: 0 PID: 5075 at…
Does this matter?
Lower severity and a low EPSS score (0.23%). Track it; it rarely justifies an emergency change on its own.
Description
In the Linux kernel, the following vulnerability has been resolved: ext4: fix mb_cache_entry's e_refcnt leak in ext4_xattr_block_cache_find() Syzbot reports a warning as follows: ============================================ WARNING: CPU: 0 PID: 5075 at fs/mbcache.c:419 mb_cache_destroy+0x224/0x290 Modules linked in: CPU: 0 PID: 5075 Comm: syz-executor199 Not tainted 6.9.0-rc6-gb947cc5bf6d7 RIP: 0010:mb_cache_destroy+0x224/0x290 fs/mbcache.c:419 Call Trace: <TASK> ext4_put_super+0x6d4/0xcd0 fs/ext4/super.c:1375 generic_shutdown_super+0x136/0x2d0 fs/super.c:641 kill_block_super+0x44/0x90 fs/super.c:1675 ext4_kill_sb+0x68/0xa0 fs/ext4/super.c:7327 [...] ============================================ This is because when finding an entry in ext4_xattr_block_cache_find(), if ext4_sb_bread() returns -ENOMEM, the ce's e_refcnt, which has already grown in the __entry_find(), won't be put away, and eventually trigger the above issue in mb_cache_destroy() due to reference count leakage. So call mb_cache_entry_put() on the -ENOMEM error branch as a quick fix.
- CVSS 3.1
- 5.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 0.23% probability · 14th percentile
- CISA KEV
- Not listed
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/0c0b4a49d3e7f49690a6827a41faeffad5df7e21Patch
- https://git.kernel.org/stable/c/681ff9a09accd8a4379f8bd30b7a1641ee19bb3ePatch
- https://git.kernel.org/stable/c/76dc776153a47372719d664e0fc50d6355791abbPatch
- https://git.kernel.org/stable/c/896a7e7d0d555ad8b2b46af0c2fa7de7467f9483Patch
- https://git.kernel.org/stable/c/9ad75e78747b5a50dc5a52f0f8e92e920a653f16Patch
- https://git.kernel.org/stable/c/a95df6f04f2c37291adf26a74205cde0314d4577Patch
- https://git.kernel.org/stable/c/b37c0edef4e66fb21a2fbc211471195a383e5ab8Patch
- https://git.kernel.org/stable/c/e941b712e758f615d311946bf98216e79145ccd9Patch
- https://git.kernel.org/stable/c/0c0b4a49d3e7f49690a6827a41faeffad5df7e21Patch
- https://git.kernel.org/stable/c/681ff9a09accd8a4379f8bd30b7a1641ee19bb3ePatch
- https://git.kernel.org/stable/c/76dc776153a47372719d664e0fc50d6355791abbPatch
- https://git.kernel.org/stable/c/896a7e7d0d555ad8b2b46af0c2fa7de7467f9483Patch
- https://git.kernel.org/stable/c/9ad75e78747b5a50dc5a52f0f8e92e920a653f16Patch
- https://git.kernel.org/stable/c/a95df6f04f2c37291adf26a74205cde0314d4577Patch
- https://git.kernel.org/stable/c/b37c0edef4e66fb21a2fbc211471195a383e5ab8Patch
- https://git.kernel.org/stable/c/e941b712e758f615d311946bf98216e79145ccd9Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.