CVE-2022-50273

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

f2fs: fix to do sanity check on destination blkaddr during recovery

As Wenqing Liu reported in bugzilla:

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

loop5: detected capacity change from 0 to 131072 F2FS-fs (loop5): recoverinode: ino = 6, name = hln, inline = 1 F2FS-fs (loop5): recoverdata: ino = 6 (isize: recover) err = 0 F2FS-fs (loop5): recoverinode: ino = 6, name = hln, inline = 1 F2FS-fs (loop5): recoverdata: ino = 6 (isize: recover) err = 0 F2FS-fs (loop5): recoverinode: ino = 6, name = hln, inline = 1 F2FS-fs (loop5): recoverdata: ino = 6 (isize: recover) err = 0 F2FS-fs (loop5): Bitmap was wrongly set, blk:5634 ------------[ cut here ]------------ WARNING: CPU: 3 PID: 1013 at fs/f2fs/segment.c:2198 RIP: 0010:updatesitentry+0xa55/0x10b0 [f2fs] Call Trace: <TASK> f2fsdoreplaceblock+0xa98/0x1890 [f2fs] f2fsreplaceblock+0xeb/0x180 [f2fs] recoverdata+0x1a69/0x6ae0 [f2fs] f2fsrecoverfsyncdata+0x120d/0x1fc0 [f2fs] f2fsfillsuper+0x4665/0x61e0 [f2fs] mountbdev+0x2cf/0x3b0 legacygettree+0xed/0x1d0 vfsgettree+0x81/0x2b0 pathmount+0x47e/0x19d0 do_mount+0xce/0xf0 __x64sysmount+0x12c/0x1a0 dosyscall64+0x38/0x90 entrySYSCALL64afterhwframe+0x63/0xcd

If we enable CONFIGF2FSCHECK_FS config, it will trigger a kernel panic instead of warning.

The root cause is: in fuzzed image, SIT table is inconsistent with inode mapping table, result in triggering such warning during SIT table update.

This patch introduces a new flag DATAGENERICENHANCEUPDATE, w/ this flag, data block recovery flow can check destination blkaddr's validation in SIT table, and skip f2fsreplace_block() to avoid inconsistent status.