Description

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

References 6

• git.kernel.org https://git.kernel.org/stable/c/0922ad64ccefa3e483e84355942b86e13c8fea68
• git.kernel.org https://git.kernel.org/stable/c/4a8e8bf280703e04e0b9d91f101e1fdd9a5bd09e
• git.kernel.org https://git.kernel.org/stable/c/73687c53919f49dff3852155621dab7a35c52854
• git.kernel.org https://git.kernel.org/stable/c/c6ad7fd16657ebd34a87a97d9588195aae87597d
• git.kernel.org https://git.kernel.org/stable/c/c99860f9a75079f339ed7670425b1ac58f26e2ff
• git.kernel.org https://git.kernel.org/stable/c/e168f819bfa42459b14f479e55ebd550bcc78899

Remediation