In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to do sanity check on node footer for non inode dnode
As syzbot reported below:
------------[ cut here ]------------
kernel BUG at fs/f2fs/file.c:1243!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5354 Comm: syz.0.0 Not tainted 6.17.0-rc1-syzkaller-00211-g90d970cade8e #0 PREEMPT(full)
RIP: 0010:f2fs_truncate_hole+0x69e/0x6c0 fs/f2fs/file.c:1243
Call Trace:
<TASK>
f2fs_punch_hole+0x2db/0x330 fs/f2fs/file.c:1306
f2fs_fallocate+0x546/0x990 fs/f2fs/file.c:2018
vfs_fallocate+0x666/0x7e0 fs/open.c:342
ksys_fallocate fs/open.c:366 [inline]
__do_sys_fallocate fs/open.c:371 [inline]
__se_sys_fallocate fs/open.c:369 [inline]
__x64_sys_fallocate+0xc0/0x110 fs/open.c:369
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
RIP: 0033:0x7f1e65f8ebe9
w/ a fuzzed image, f2fs may encounter panic due to it detects inconsistent
truncation range in direct node in f2fs_truncate_hole().
The root cause is: a non-inode dnode may has the same footer.ino and
footer.nid, so the dnode will be parsed as an inode, then ADDRS_PER_PAGE()
may return wrong blkaddr count which may be 923 typically, by chance,
dn.ofs_in_node is equal to 923, then count can be calculated to 0 in below
statement, later it will trigger panic w/ f2fs_bug_on(, count == 0 || ...).
count = min(end_offset - dn.ofs_in_node, pg_end - pg_start);
This patch introduces a new node_type NODE_TYPE_NON_INODE, then allowing
passing the new_type to sanity_check_node_footer in f2fs_get_node_folio()
to detect corruption that a non-inode dnode has the same footer.ino and
footer.nid.
Scripts to reproduce:
mkfs.f2fs -f /dev/vdb
mount /dev/vdb /mnt/f2fs
touch /mnt/f2fs/foo
touch /mnt/f2fs/bar
dd if=/dev/zero of=/mnt/f2fs/foo bs=1M count=8
umount /mnt/f2fs
inject.f2fs --node --mb i_nid --nid 4 --idx 0 --val 5 /dev/vdb
mount /dev/vdb /mnt/f2fs
xfs_io /mnt/f2fs/foo -c "fpunch 6984k 4k"
f2fs: fix to do sanity check on node footer for non inode dnode
As syzbot reported below:
------------[ cut here ]------------
kernel BUG at fs/f2fs/file.c:1243!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5354 Comm: syz.0.0 Not tainted 6.17.0-rc1-syzkaller-00211-g90d970cade8e #0 PREEMPT(full)
RIP: 0010:f2fs_truncate_hole+0x69e/0x6c0 fs/f2fs/file.c:1243
Call Trace:
<TASK>
f2fs_punch_hole+0x2db/0x330 fs/f2fs/file.c:1306
f2fs_fallocate+0x546/0x990 fs/f2fs/file.c:2018
vfs_fallocate+0x666/0x7e0 fs/open.c:342
ksys_fallocate fs/open.c:366 [inline]
__do_sys_fallocate fs/open.c:371 [inline]
__se_sys_fallocate fs/open.c:369 [inline]
__x64_sys_fallocate+0xc0/0x110 fs/open.c:369
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
RIP: 0033:0x7f1e65f8ebe9
w/ a fuzzed image, f2fs may encounter panic due to it detects inconsistent
truncation range in direct node in f2fs_truncate_hole().
The root cause is: a non-inode dnode may has the same footer.ino and
footer.nid, so the dnode will be parsed as an inode, then ADDRS_PER_PAGE()
may return wrong blkaddr count which may be 923 typically, by chance,
dn.ofs_in_node is equal to 923, then count can be calculated to 0 in below
statement, later it will trigger panic w/ f2fs_bug_on(, count == 0 || ...).
count = min(end_offset - dn.ofs_in_node, pg_end - pg_start);
This patch introduces a new node_type NODE_TYPE_NON_INODE, then allowing
passing the new_type to sanity_check_node_footer in f2fs_get_node_folio()
to detect corruption that a non-inode dnode has the same footer.ino and
footer.nid.
Scripts to reproduce:
mkfs.f2fs -f /dev/vdb
mount /dev/vdb /mnt/f2fs
touch /mnt/f2fs/foo
touch /mnt/f2fs/bar
dd if=/dev/zero of=/mnt/f2fs/foo bs=1M count=8
umount /mnt/f2fs
inject.f2fs --node --mb i_nid --nid 4 --idx 0 --val 5 /dev/vdb
mount /dev/vdb /mnt/f2fs
xfs_io /mnt/f2fs/foo -c "fpunch 6984k 4k"
Metrics
Affected Vendors & Products
Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Wed, 29 Oct 2025 11:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Linux
Linux linux Kernel |
|
| Vendors & Products |
Linux
Linux linux Kernel |
Wed, 29 Oct 2025 00:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Tue, 28 Oct 2025 09:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to do sanity check on node footer for non inode dnode As syzbot reported below: ------------[ cut here ]------------ kernel BUG at fs/f2fs/file.c:1243! Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI CPU: 0 UID: 0 PID: 5354 Comm: syz.0.0 Not tainted 6.17.0-rc1-syzkaller-00211-g90d970cade8e #0 PREEMPT(full) RIP: 0010:f2fs_truncate_hole+0x69e/0x6c0 fs/f2fs/file.c:1243 Call Trace: <TASK> f2fs_punch_hole+0x2db/0x330 fs/f2fs/file.c:1306 f2fs_fallocate+0x546/0x990 fs/f2fs/file.c:2018 vfs_fallocate+0x666/0x7e0 fs/open.c:342 ksys_fallocate fs/open.c:366 [inline] __do_sys_fallocate fs/open.c:371 [inline] __se_sys_fallocate fs/open.c:369 [inline] __x64_sys_fallocate+0xc0/0x110 fs/open.c:369 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 RIP: 0033:0x7f1e65f8ebe9 w/ a fuzzed image, f2fs may encounter panic due to it detects inconsistent truncation range in direct node in f2fs_truncate_hole(). The root cause is: a non-inode dnode may has the same footer.ino and footer.nid, so the dnode will be parsed as an inode, then ADDRS_PER_PAGE() may return wrong blkaddr count which may be 923 typically, by chance, dn.ofs_in_node is equal to 923, then count can be calculated to 0 in below statement, later it will trigger panic w/ f2fs_bug_on(, count == 0 || ...). count = min(end_offset - dn.ofs_in_node, pg_end - pg_start); This patch introduces a new node_type NODE_TYPE_NON_INODE, then allowing passing the new_type to sanity_check_node_footer in f2fs_get_node_folio() to detect corruption that a non-inode dnode has the same footer.ino and footer.nid. Scripts to reproduce: mkfs.f2fs -f /dev/vdb mount /dev/vdb /mnt/f2fs touch /mnt/f2fs/foo touch /mnt/f2fs/bar dd if=/dev/zero of=/mnt/f2fs/foo bs=1M count=8 umount /mnt/f2fs inject.f2fs --node --mb i_nid --nid 4 --idx 0 --val 5 /dev/vdb mount /dev/vdb /mnt/f2fs xfs_io /mnt/f2fs/foo -c "fpunch 6984k 4k" | |
| Title | f2fs: fix to do sanity check on node footer for non inode dnode | |
| References |
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2025-10-28T09:32:31.806Z
Reserved: 2025-04-16T07:20:57.152Z
Link: CVE-2025-40025
No data.
Status : Received
Published: 2025-10-28T10:15:40.920
Modified: 2025-10-28T10:15:40.920
Link: CVE-2025-40025
OpenCVE Enrichment
Updated: 2025-10-29T10:58:45Z