Medium · published February 26, 2025
In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to avoid f2fs_bug_on() in dec_valid_node_count()
As Yanming reported in bugzilla:
https://bugzilla.kernel.org/show_bug.cgi?id=215897
I have encountered a bug in F2FS file system in kernel v5.17.
The kernel should enable CONFIG_KASAN=y and CONFIG_KASAN_INLINE=y. You can
reproduce the bug by running the following commands:
The kernel message is shown below:
kernel BUG at fs/f2fs/f2fs.h:2511!
Call Trace:
f2fs_remove_inode_page+0x2a2/0x830
f2fs_evict_inode+0x9b7/0x1510
evict+0x282/0x4e0
do_unlinkat+0x33a/0x540
__x64_sys_unlinkat+0x8e/0xd0
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
The root cause is: .total_valid_block_count or .total_valid_node_count
could fuzzed to zero, then once dec_valid_node_count() was called, it
will cause BUG_ON(), this patch fixes to print warning info and set
SBI_NEED_FSCK into CP instead of panic.
| Product | Versions | Fixed in |
|---|---|---|
| linux/linux_kernel | ≥ 3.8, < 5.4.198 | 5.4.198 |
| linux/linux_kernel | ≥ 5.5, < 5.10.121 | 5.10.121 |
| linux/linux_kernel | ≥ 5.11, < 5.15.46 | 5.15.46 |
| linux/linux_kernel | ≥ 5.16, < 5.17.14 | 5.17.14 |
| linux/linux_kernel | ≥ 5.18, < 5.18.3 | 5.18.3 |