f2fs: fix to don't set SB_RDONLY in f2fs_handle_critical_error()
Summary
f2fs: fix to don't set SB_RDONLY in f2fs_handle_critical_error()
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to don't set SB_RDONLY in f2fs_handle_critical_error()
syzbot reports a f2fs bug as below:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 58 at kernel/rcu/sync.c:177 rcu_sync_dtor+0xcd/0x180 kernel/rcu/sync.c:177
CPU: 1 UID: 0 PID: 58 Comm: kworker/1:2 Not tainted 6.10.0-syzkaller-12562-g1722389b0d86 #0
Workqueue: events destroy_super_work
RIP: 0010:rcu_sync_dtor+0xcd/0x180 kernel/rcu/sync.c:177
Call Trace:
percpu_free_rwsem+0x41/0x80 kernel/locking/percpu-rwsem.c:42
destroy_super_work+0xec/0x130 fs/super.c:282
process_one_work kernel/workqueue.c:3231 [inline]
process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
worker_thread+0x86d/0xd40 kernel/workqueue.c:3390
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
As Christian Brauner pointed out [1]: the root cause is f2fs sets
SB_RDONLY flag in internal function, rather than setting the flag
covered w/ sb->s_umount semaphore via remount procedure, then below
race condition causes this bug:
- freeze_super()
- sb_wait_write(sb, SB_FREEZE_WRITE)
- sb_wait_write(sb, SB_FREEZE_PAGEFAULT)
- sb_wait_write(sb, SB_FREEZE_FS)
- f2fs_handle_critical_error
- sb->s_flags |= SB_RDONLY - thaw_super
- thaw_super_locked
- sb_rdonly() is true, so it skips
sb_freeze_unlock(sb, SB_FREEZE_FS) - deactivate_locked_supe…
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2024-47689 linux Fixed in: 6.11.2-1
- Ubuntu UBUNTU-CVE-2024-47689 linux
References
- advisory github.com
- advisory nvd.nist.gov
- package git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org