CVE-2022-49428 f2fs: fix to do sanity check on inline_dots inode
A missing sanity check in the f2fs filesystem allows a local attacker to cause a kernel panic via a crafted image, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2022-49428?
CVE-2022-49428 is a medium-severity vulnerability in Linux kernel, published on 26 Feb 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to do sanity check on inline_dots inode
As Wenqing reported in bugzilla:
https://bugzilla.kernel.org/show_bug.cgi?id=215765
It will cause a kernel panic with steps: - mkdir mnt - mount tmp40.img mnt - ls mnt
folio_mark_dirty+0x33/0x50 f2fs_add_regular_entry+0x541/0xad0 [f2fs] f2fs_add_dentry+0x6c/0xb0 [f2fs] f2fs_do_add_link+0x182/0x230 [f2fs] __recover_dot_dentries+0x2d6/0x470 [f2fs] f2fs_lookup+0x5af/0x6a0 [f2fs] __lookup_slow+0xac/0x200 lookup_slow+0x45/0x70 walk_component+0x16c/0x250 path_lookupat+0x8b/0x1f0 filename_lookup+0xef/0x250 user_path_at_empty+0x46/0x70 vfs_statx+0x98/0x190 __do_sys_newlstat+0x41/0x90 __x64_sys_newlstat+0x1a/0x30 do_syscall_64+0x37/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xae
The root cause is for special file: e.g. character, block, fifo or socket file, f2fs doesn't assign address space operations pointer array for mapping->a_ops field, so, in a fuzzed image, if inline_dots flag was tagged in special file, during lookup(), when f2fs runs into __recover_dot_dentries(), it will cause NULL pointer access once f2fs_add_regular_entry() calls a_ops->set_dirty_page().
Weakness: CWE-476
Which versions are affected by CVE-2022-49428?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-49428?
Apply the vendor's patch.
Is CVE-2022-49428 being exploited?
There is no known exploitation of CVE-2022-49428 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2022-49428, GHSA-fvjw-79jq-h4jj, ROOT-OS-DEBIAN-11-CVE-2022-49428, UBUNTU-CVE-2022-49428.