Attacker Value
Unknown
(0 users assessed)
Exploitability
Unknown
(0 users assessed)
User Interaction
None
Privileges Required
Low
Attack Vector
Local
0

CVE-2024-42297

Disclosure Date: August 17, 2024
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

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().

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CVSS V3 Severity and Metrics
Base Score:
5.5 Medium
Impact Score:
3.6
Exploitability Score:
1.8
Vector:
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector (AV):
Local
Attack Complexity (AC):
Low
Privileges Required (PR):
Low
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
None
Integrity (I):
None
Availability (A):
High

General Information

Vendors

  • linux

Products

  • linux kernel
Technical Analysis