CVE-2022-49380

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.