CVE-2022-49708
ext4: fix bug_on ext4_mb_use_inode_pa
- Published
- Updated
- Reserved
- Assigned by
- Linux
Description
In the Linux kernel, the following vulnerability has been resolved: ext4: fix bug_on ext4_mb_use_inode_pa Hulk Robot reported a BUG_ON: ================================================================== kernel BUG at fs/ext4/mballoc.c:3211! [...] RIP: 0010:ext4_mb_mark_diskspace_used.cold+0x85/0x136f [...] Call Trace: ext4_mb_new_blocks+0x9df/0x5d30 ext4_ext_map_blocks+0x1803/0x4d80 ext4_map_blocks+0x3a4/0x1a10 ext4_writepages+0x126d/0x2c30 do_writepages+0x7f/0x1b0 __filemap_fdatawrite_range+0x285/0x3b0 file_write_and_wait_range+0xb1/0x140 ext4_sync_file+0x1aa/0xca0 vfs_fsync_range+0xfb/0x260 do_fsync+0x48/0xa0 [...] ================================================================== Above issue may happen as follows: ------------------------------------- do_fsync vfs_fsync_range ext4_sync_file file_write_and_wait_range __filemap_fdatawrite_range do_writepages ext4_writepages mpage_map_and_submit_extent mpage_map_one_extent ext4_map_blocks ext4_mb_new_blocks ext4_mb_normalize_request >>> start + size <= ac->ac_o_ex.fe_logical ext4_mb_regular_allocator ext4_mb_simple_scan_group ext4_mb_use_best_found ext4_mb_new_preallocation ext4_mb_new_inode_pa ext4_mb_use_inode_pa >>> set ac->ac_b_ex.fe_len <= 0 ext4_mb_mark_diskspace_used >>> BUG_ON(ac->ac_b_ex.fe_len <= 0); we can easily reproduce this problem with the following commands: `fallocate -l100M disk` `mkfs.ext4 -b 1024 -g 256 disk` `mount disk /mnt` `fsstress -d /mnt -l 0 -n 1000 -p 1` The size must be smaller than or equal to EXT4_BLOCKS_PER_GROUP. Therefore, "start + size <= ac->ac_o_ex.fe_logical" may occur when the size is truncated. So start should be the start position of the group where ac_o_ex.fe_logical is located after alignment. In addition, when the value of fe_logical or EXT4_BLOCKS_PER_GROUP is very large, the value calculated by start_off is more accurate.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Analyzed | 3.1 | Medium5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.28% · top 79% of all CVEs (6 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.5.
Weakness
Affected products
- affected fc6c2da174edd7a7b760b12c60d432d300e05cca – < 6880fb2e64331b9fdc85d3f32b1d7e81ad8703f1
- affected cd648b8a8fd5071d232242d5ee7ee3c0815776af – < a37c1359714da42517dd19d36fc3c4d17edba832
- affected cd648b8a8fd5071d232242d5ee7ee3c0815776af – < 5707d721d1819db57dba57b1d4623034fcb32047
- affected cd648b8a8fd5071d232242d5ee7ee3c0815776af – < a6b31616e5afe1d3972cb0682a373e50597faf5c
- affected cd648b8a8fd5071d232242d5ee7ee3c0815776af – < 6fdaf31ad5f3d3afab744dfd9a8b0d9142aa881f
- affected cd648b8a8fd5071d232242d5ee7ee3c0815776af – < 90f0f9d45dff0128c0fca0d2358c4153b024afa6
- affected cd648b8a8fd5071d232242d5ee7ee3c0815776af – < 887a3e9ad4b8309a2266bce7ae749b2bf1f7a687
- affected cd648b8a8fd5071d232242d5ee7ee3c0815776af – < a08f789d2ab5242c07e716baf9a835725046be89
- affected f213db429b883a2d5403de0b1ce92fb7d7ee979e
- affected 98f58e05231f835dfb09359e3b5e3a886fe8f189
- affected c1664e9bcf6291c0ceb8599f57c8cf493526abe6
- affected 37cf4ab1ba60c30ca9fd0fe3b9993b24cb87886a
- affected 75f37dab088eb84ff25a49e59371f01ea3f44aa7
- affected 8774c73cf6963310395823ed7077ea12943ea0f3
- affected c4fbdc0124799f1772f4d886b7f2e1a6f881d195
- affected 4.9.14 – < 4.9.320
- affected 3.2.89 – < 3.3
- affected 3.10.107 – < 3.11
- affected 3.12.72 – < 3.13
- affected 3.16.44 – < 3.17
- affected 4.1.40 – < 4.2
- affected 4.4.53 – < 4.5
- affected 4.10.2 – < 4.11
- affected 4.11
- unaffected < 4.11
- unaffected 4.9.320 – ≤ 4.9.*
- unaffected 4.14.285 – ≤ 4.14.*
- unaffected 4.19.249 – ≤ 4.19.*
- unaffected 5.4.200 – ≤ 5.4.*
- unaffected 5.10.124 – ≤ 5.10.*
- unaffected 5.15.49 – ≤ 5.15.*
- unaffected 5.18.6 – ≤ 5.18.*
- unaffected 5.19 – ≤ *
References (8)
- https://git.kernel.org/stable/c/6880fb2e64331b9fdc85d3f32b1d7e81ad8703f1 (opens in a new tab)
- https://git.kernel.org/stable/c/a37c1359714da42517dd19d36fc3c4d17edba832 (opens in a new tab)
- https://git.kernel.org/stable/c/5707d721d1819db57dba57b1d4623034fcb32047 (opens in a new tab)
- https://git.kernel.org/stable/c/a6b31616e5afe1d3972cb0682a373e50597faf5c (opens in a new tab)
- https://git.kernel.org/stable/c/6fdaf31ad5f3d3afab744dfd9a8b0d9142aa881f (opens in a new tab)
- https://git.kernel.org/stable/c/90f0f9d45dff0128c0fca0d2358c4153b024afa6 (opens in a new tab)
- https://git.kernel.org/stable/c/887a3e9ad4b8309a2266bce7ae749b2bf1f7a687 (opens in a new tab)
- https://git.kernel.org/stable/c/a08f789d2ab5242c07e716baf9a835725046be89 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2022-49708)Record last updated .