CVE-2025-38163

Summary

In the Linux kernel, the following vulnerability has been resolved:

f2fs: fix to do sanity check on sbi->total_valid_block_count

syzbot reported a f2fs bug as below:

————[ cut here ]———— kernel BUG at fs/f2fs/f2fs.h:2521! RIP: 0010:dec_valid_block_count+0x3b2/0x3c0 fs/f2fs/f2fs.h:2521 Call Trace: f2fs_truncate_data_blocks_range+0xc8c/0x11a0 fs/f2fs/file.c:695 truncate_dnode+0x417/0x740 fs/f2fs/node.c:973 truncate_nodes+0x3ec/0xf50 fs/f2fs/node.c:1014 f2fs_truncate_inode_blocks+0x8e3/0x1370 fs/f2fs/node.c:1197 f2fs_do_truncate_blocks+0x840/0x12b0 fs/f2fs/file.c:810 f2fs_truncate_blocks+0x10d/0x300 fs/f2fs/file.c:838 f2fs_truncate+0x417/0x720 fs/f2fs/file.c:888 f2fs_setattr+0xc4f/0x12f0 fs/f2fs/file.c:1112 notify_change+0xbca/0xe90 fs/attr.c:552 do_truncate+0x222/0x310 fs/open.c:65 handle_truncate fs/namei.c:3466 [inline] do_open fs/namei.c:3849 [inline] path_openat+0x2e4f/0x35d0 fs/namei.c:4004 do_filp_open+0x284/0x4e0 fs/namei.c:4031 do_sys_openat2+0x12b/0x1d0 fs/open.c:1429 do_sys_open fs/open.c:1444 [inline] __do_sys_creat fs/open.c:1522 [inline] __se_sys_creat fs/open.c:1516 [inline] __x64_sys_creat+0x124/0x170 fs/open.c:1516 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94

The reason is: in fuzzed image, sbi->total_valid_block_count is inconsistent w/ mapped blocks indexed by inode, so, we should not trigger panic for such case, instead, let's print log and set fsck flag.

Affected Software

Weaknesses

ADP Enrichment

CVE Program Container

Additional References

• https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
• https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html

References

• https://git.kernel.org/stable/c/49bc7bf38e42cfa642787e947f5721696ea73ac3
• https://git.kernel.org/stable/c/f1b743c1955151bd392539b739a3ad155296be13
• https://git.kernel.org/stable/c/6a324d77f7ea1a91d55c4b6ad970e3ac9ab6a20d
• https://git.kernel.org/stable/c/25f3776b58c1c45ad2e50ab4b263505b4d2378ca
• https://git.kernel.org/stable/c/a39cc43efc1bca74ed9d6cf9e60b995071f7d178
• https://git.kernel.org/stable/c/65b3f76592aed5a43c4d79375ac097acf975972b
• https://git.kernel.org/stable/c/ccc28c0397f75a3ec9539cceed9db014d7b73869
• https://git.kernel.org/stable/c/05872a167c2cab80ef186ef23cc34a6776a1a30c

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