CVE-2022-50753

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

f2fs: fix to do sanity check on summary info

As Wenqing Liu reported in bugzilla:

https://bugzilla.kernel.org/show_bug.cgi?id=216456

BUG: KASAN: use-after-free in recover_data+0x63ae/0x6ae0 [f2fs]

Read of size 4 at addr ffff8881464dcd80 by task mount/1013

CPU: 3 PID: 1013 Comm: mount Tainted: G W 6.0.0-rc4 #1

Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014

Call Trace:

dump_stack_lvl+0x45/0x5e

print_report.cold+0xf3/0x68d

kasan_report+0xa8/0x130

recover_data+0x63ae/0x6ae0 [f2fs]

f2fs_recover_fsync_data+0x120d/0x1fc0 [f2fs]

f2fs_fill_super+0x4665/0x61e0 [f2fs]

mount_bdev+0x2cf/0x3b0

legacy_get_tree+0xed/0x1d0

vfs_get_tree+0x81/0x2b0

path_mount+0x47e/0x19d0

do_mount+0xce/0xf0

__x64_sys_mount+0x12c/0x1a0

do_syscall_64+0x38/0x90

entry_SYSCALL_64_after_hwframe+0x63/0xcd

The root cause is: in fuzzed image, SSA table is corrupted: ofs_in_node

is larger than ADDRS_PER_PAGE(), result in out-of-range access on 4k-size

page.

- recover_data

- do_recover_data

- check_index_in_prev_nodes

- f2fs_data_blkaddr

This patch adds sanity check on summary info in recovery and GC flow

in where the flows rely on them.

After patch:

[ 29.310883] F2FS-fs (loop0): Inconsistent ofs_in_node:65286 in summary, ino:0, nid:6, max:1018