Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: ext4: only dirty folios when data journaling regular files fstest generic/388 occasionally reproduces a crash that looks as follows: BUG: kernel NULL pointer dereference, address: 0000000000000000 ... Call Trace: <TASK> ext4_block_zero_page_range+0x30c/0x380 [ext4] ext4_truncate+0x436/0x440 [ext4] ext4_process_orphan+0x5d/0x110 [ext4] ext4_orphan_cleanup+0x124/0x4f0 [ext4] ext4_fill_super+0x262d/0x3110 [ext4] get_tree_bdev_flags+0x132/0x1d0 vfs_get_tree+0x26/0xd0 vfs_cmd_create+0x59/0xe0 __do_sys_fsconfig+0x4ed/0x6b0 do_syscall_64+0x82/0x170 ... This occurs when processing a symlink inode from the orphan list. The partial block zeroing code in the truncate path calls ext4_dirty_journalled_data() -> folio_mark_dirty(). The latter calls mapping->a_ops->dirty_folio(), but symlink inodes are not assigned an a_ops vector in ext4, hence the crash. To avoid this problem, update the ext4_dirty_journalled_data() helper to only mark the folio dirty on regular files (for which a_ops is assigned). This also matches the journaling logic in the ext4_symlink() creation path, where ext4_handle_dirty_metadata() is called directly.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected d84c9ebdac1e39bc7b036c0c829ee8c1956edabc before cf6a4c4ac7b6e3214f25df594c9689a62f1bb456; affected d84c9ebdac1e39bc7b036c0c829ee8c1956edabc before be5f3061a6f904e3674257879e71881ceee5b673; affected d84c9ebdac1e39bc7b036c0c829ee8c1956edabc before d7af6eee8cd60f55aa8c5fe2b91f11ec0c9a0f27; affected d84c9ebdac1e39bc7b036c0c829ee8c1956edabc before e26268ff1dcae5662c1b96c35f18cfa6ab73d9de |
| Linux / Linux | affected 6.4; unaffected 0 before 6.4; unaffected 6.6.95 through 6.6.*; unaffected 6.12.35 through 6.12.*; unaffected 6.15.4 through 6.15.*; unaffected 6.16 through * |
CWE
No CWE identifiers supplied.