CVE-2024-42297 f2fs: fix to don't dirty inode for readonly filesystem
A local attacker can trigger a kernel panic in the f2fs filesystem by mounting it as read-only, causing a 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-2024-42297?
CVE-2024-42297 is a high-severity denial of service vulnerability in Linux kernel, published on 17 Aug 2024. 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 don't dirty inode for readonly filesystem
syzbot reports f2fs bug as below:
kernel BUG at fs/f2fs/inode.c:933! RIP: 0010:f2fs_evict_inode+0x1576/0x1590 fs/f2fs/inode.c:933 Call Trace: evict+0x2a4/0x620 fs/inode.c:664 dispose_list fs/inode.c:697 [inline] evict_inodes+0x5f8/0x690 fs/inode.c:747 generic_shutdown_super+0x9d/0x2c0 fs/super.c:675 kill_block_super+0x44/0x90 fs/super.c:1667 kill_f2fs_super+0x303/0x3b0 fs/f2fs/super.c:4894 deactivate_locked_super+0xc1/0x130 fs/super.c:484 cleanup_mnt+0x426/0x4c0 fs/namespace.c:1256 task_work_run+0x24a/0x300 kernel/task_work.c:180 ptrace_notify+0x2cd/0x380 kernel/signal.c:2399 ptrace_report_syscall include/linux/ptrace.h:411 [inline] ptrace_report_syscall_exit include/linux/ptrace.h:473 [inline] syscall_exit_work kernel/entry/common.c:251 [inline] syscall_exit_to_user_mode_prepare kernel/entry/common.c:278 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline] syscall_exit_to_user_mode+0x15c/0x280 kernel/entry/common.c:296 do_syscall_64+0x50/0x110 arch/x86/entry/common.c:88 entry_SYSCALL_64_after_hwframe+0x63/0x6b
The root cause is: - do_sys_open - f2fs_lookup - __f2fs_find_entry - f2fs_i_depth_write - f2fs_mark_inode_dirty_sync - f2fs_dirty_inode - set_inode_flag(inode, FI_DIRTY_INODE)
- umount - kill_f2fs_super - kill_block_super - generic_shutdown_super - sync_filesystem : sb is readonly, skip sync_filesystem() - evict_inodes - iput - f2fs_evict_inode - f2fs_bug_on(sbi, is_inode_flag_set(inode, FI_DIRTY_INODE)) : trigger kernel panic
When we try to repair i_current_depth in readonly filesystem, let's skip dirty inode to avoid panic in later f2fs_evict_inode().
Which versions are affected by CVE-2024-42297?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-42297?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2024-42297 being exploited?
There is no known exploitation of CVE-2024-42297 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-49746, BELL-CVE-2024-42297, DEBIAN-CVE-2024-42297, GHSA-q637-fwgw-hj6c, UBUNTU-CVE-2024-42297.