fkie_cve-2025-40138
Vulnerability from fkie_nvd
Published
2025-11-12 11:15
Modified
2025-11-12 16:19
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to avoid NULL pointer dereference in f2fs_check_quota_consistency() syzbot reported a f2fs bug as below: Oops: gen[ 107.736417][ T5848] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 1 UID: 0 PID: 5848 Comm: syz-executor263 Tainted: G W 6.17.0-rc1-syzkaller-00014-g0e39a731820a #0 PREEMPT_{RT,(full)} RIP: 0010:strcmp+0x3c/0xc0 lib/string.c:284 Call Trace: <TASK> f2fs_check_quota_consistency fs/f2fs/super.c:1188 [inline] f2fs_check_opt_consistency+0x1378/0x2c10 fs/f2fs/super.c:1436 __f2fs_remount fs/f2fs/super.c:2653 [inline] f2fs_reconfigure+0x482/0x1770 fs/f2fs/super.c:5297 reconfigure_super+0x224/0x890 fs/super.c:1077 do_remount fs/namespace.c:3314 [inline] path_mount+0xd18/0xfe0 fs/namespace.c:4112 do_mount fs/namespace.c:4133 [inline] __do_sys_mount fs/namespace.c:4344 [inline] __se_sys_mount+0x317/0x410 fs/namespace.c:4321 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The direct reason is f2fs_check_quota_consistency() may suffer null-ptr-deref issue in strcmp(). The bug can be reproduced w/ below scripts: mkfs.f2fs -f /dev/vdb mount -t f2fs -o usrquota /dev/vdb /mnt/f2fs quotacheck -uc /mnt/f2fs/ umount /mnt/f2fs mount -t f2fs -o usrjquota=aquota.user,jqfmt=vfsold /dev/vdb /mnt/f2fs mount -t f2fs -o remount,usrjquota=,jqfmt=vfsold /dev/vdb /mnt/f2fs umount /mnt/f2fs So, before old_qname and new_qname comparison, we need to check whether they are all valid pointers, fix it.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3f3458852bbfe79c60f2412b8b04677b96688b6e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/930a9a6ee8e7ffa20af4bffbfc2bbd21d83bf81c
Impacted products
Vendor Product Version


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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to avoid NULL pointer dereference in f2fs_check_quota_consistency()\n\nsyzbot reported a f2fs bug as below:\n\nOops: gen[  107.736417][ T5848] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI\nKASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]\nCPU: 1 UID: 0 PID: 5848 Comm: syz-executor263 Tainted: G        W           6.17.0-rc1-syzkaller-00014-g0e39a731820a #0 PREEMPT_{RT,(full)}\nRIP: 0010:strcmp+0x3c/0xc0 lib/string.c:284\nCall Trace:\n \u003cTASK\u003e\n f2fs_check_quota_consistency fs/f2fs/super.c:1188 [inline]\n f2fs_check_opt_consistency+0x1378/0x2c10 fs/f2fs/super.c:1436\n __f2fs_remount fs/f2fs/super.c:2653 [inline]\n f2fs_reconfigure+0x482/0x1770 fs/f2fs/super.c:5297\n reconfigure_super+0x224/0x890 fs/super.c:1077\n do_remount fs/namespace.c:3314 [inline]\n path_mount+0xd18/0xfe0 fs/namespace.c:4112\n do_mount fs/namespace.c:4133 [inline]\n __do_sys_mount fs/namespace.c:4344 [inline]\n __se_sys_mount+0x317/0x410 fs/namespace.c:4321\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nThe direct reason is f2fs_check_quota_consistency() may suffer null-ptr-deref\nissue in strcmp().\n\nThe bug can be reproduced w/ below scripts:\nmkfs.f2fs -f /dev/vdb\nmount -t f2fs -o usrquota /dev/vdb /mnt/f2fs\nquotacheck -uc /mnt/f2fs/\numount /mnt/f2fs\nmount -t f2fs -o usrjquota=aquota.user,jqfmt=vfsold /dev/vdb /mnt/f2fs\nmount -t f2fs -o remount,usrjquota=,jqfmt=vfsold /dev/vdb /mnt/f2fs\numount /mnt/f2fs\n\nSo, before old_qname and new_qname comparison, we need to check whether\nthey are all valid pointers, fix it."
    }
  ],
  "id": "CVE-2025-40138",
  "lastModified": "2025-11-12T16:19:12.850",
  "metrics": {},
  "published": "2025-11-12T11:15:43.553",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3f3458852bbfe79c60f2412b8b04677b96688b6e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/930a9a6ee8e7ffa20af4bffbfc2bbd21d83bf81c"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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