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CVE-2022-49708

ext4: fix bug_on ext4_mb_use_inode_pa PUBLISHED

Description (CNA)

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.

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected fc6c2da174edd7a7b760b12c60d432d300e05cca before 6880fb2e64331b9fdc85d3f32b1d7e81ad8703f1; affected cd648b8a8fd5071d232242d5ee7ee3c0815776af before a37c1359714da42517dd19d36fc3c4d17edba832; affected cd648b8a8fd5071d232242d5ee7ee3c0815776af before 5707d721d1819db57dba57b1d4623034fcb32047; affected cd648b8a8fd5071d232242d5ee7ee3c0815776af before a6b31616e5afe1d3972cb0682a373e50597faf5c; affected cd648b8a8fd5071d232242d5ee7ee3c0815776af before 6fdaf31ad5f3d3afab744dfd9a8b0d9142aa881f; affected cd648b8a8fd5071d232242d5ee7ee3c0815776af before 90f0f9d45dff0128c0fca0d2358c4153b024afa6; affected cd648b8a8fd5071d232242d5ee7ee3c0815776af before 887a3e9ad4b8309a2266bce7ae749b2bf1f7a687; affected cd648b8a8fd5071d232242d5ee7ee3c0815776af before a08f789d2ab5242c07e716baf9a835725046be89; affected f213db429b883a2d5403de0b1ce92fb7d7ee979e; affected 98f58e05231f835dfb09359e3b5e3a886fe8f189; affected c1664e9bcf6291c0ceb8599f57c8cf493526abe6; affected 37cf4ab1ba60c30ca9fd0fe3b9993b24cb87886a; affected 75f37dab088eb84ff25a49e59371f01ea3f44aa7; affected 8774c73cf6963310395823ed7077ea12943ea0f3; affected c4fbdc0124799f1772f4d886b7f2e1a6f881d195; affected 4.9.14 before 4.9.320; affected 3.2.89 before 3.3; affected 3.10.107 before 3.11; affected 3.12.72 before 3.13; affected 3.16.44 before 3.17; affected 4.1.40 before 4.2; affected 4.4.53 before 4.5; affected 4.10.2 before 4.11
Linux / Linuxaffected 4.11; unaffected 0 before 4.11; unaffected 4.9.320 through 4.9.*; unaffected 4.14.285 through 4.14.*; unaffected 4.19.249 through 4.19.*; unaffected 5.4.200 through 5.4.*; unaffected 5.10.124 through 5.10.*; unaffected 5.15.49 through 5.15.*; unaffected 5.18.6 through 5.18.*; unaffected 5.19 through *

CWE

No CWE identifiers supplied.

References