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): recover_inode: ino = 6, name = hln, inline = 1
F2FS-fs (loop5): recover_data: ino = 6 (i_size: recover) err = 0
F2FS-fs (loop5): recover_inode: ino = 6, name = hln, inline = 1
F2FS-fs (loop5): recover_data: ino = 6 (i_size: recover) err = 0
F2FS-fs (loop5): recover_inode: ino = 6, name = hln, inline = 1
F2FS-fs (loop5): recover_data: ino = 6 (i_size: 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:update_sit_entry+0xa55/0x10b0 [f2fs]
Call Trace:
 <TASK>
 f2fs_do_replace_block+0xa98/0x1890 [f2fs]
 f2fs_replace_block+0xeb/0x180 [f2fs]
 recover_data+0x1a69/0x6ae0 [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

If we enable CONFIG_F2FS_CHECK_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 DATA_GENERIC_ENHANCE_UPDATE, w/ this
flag, data block recovery flow can check destination blkaddr's validation
in SIT table, and skip f2fs_replace_block() to avoid inconsistent status.

Cc: stable@vger.kernel.org
Reported-by: Wenqing Liu <wenqingliu0120@gmail.com>
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/checkpoint.c

@@ -140,7 +140,7 @@ static bool __is_bitmap_valid(struct f2fs_sb_info *sbi, block_t blkaddr,
 	unsigned int segno, offset;
 	bool exist;
 
-	if (type != DATA_GENERIC_ENHANCE && type != DATA_GENERIC_ENHANCE_READ)
+	if (type == DATA_GENERIC)
 		return true;
 
 	segno = GET_SEGNO(sbi, blkaddr);
@@ -148,6 +148,13 @@ static bool __is_bitmap_valid(struct f2fs_sb_info *sbi, block_t blkaddr,
 	se = get_seg_entry(sbi, segno);
 
 	exist = f2fs_test_bit(offset, se->cur_valid_map);
+	if (exist && type == DATA_GENERIC_ENHANCE_UPDATE) {
+		f2fs_err(sbi, "Inconsistent error blkaddr:%u, sit bitmap:%d",
+			 blkaddr, exist);
+		set_sbi_flag(sbi, SBI_NEED_FSCK);
+		return exist;
+	}
+
 	if (!exist && type == DATA_GENERIC_ENHANCE) {
 		f2fs_err(sbi, "Inconsistent error blkaddr:%u, sit bitmap:%d",
 			 blkaddr, exist);
@@ -185,6 +192,7 @@ bool f2fs_is_valid_blkaddr(struct f2fs_sb_info *sbi,
 	case DATA_GENERIC:
 	case DATA_GENERIC_ENHANCE:
 	case DATA_GENERIC_ENHANCE_READ:
+	case DATA_GENERIC_ENHANCE_UPDATE:
 		if (unlikely(blkaddr >= MAX_BLKADDR(sbi) ||
 				blkaddr < MAIN_BLKADDR(sbi))) {
 			f2fs_warn(sbi, "access invalid blkaddr:%u",

fs/f2fs/f2fs.h

@@ -266,6 +266,10 @@ enum {
 					 * condition of read on truncated area
 					 * by extent_cache
 					 */
+	DATA_GENERIC_ENHANCE_UPDATE,	/*
+					 * strong check on range and segment
+					 * bitmap for update case
+					 */
 	META_GENERIC,
 };
 

fs/f2fs/recovery.c

@@ -698,6 +698,14 @@ static int do_recover_data(struct f2fs_sb_info *sbi, struct inode *inode,
 				goto err;
 			}
 
+			if (f2fs_is_valid_blkaddr(sbi, dest,
+					DATA_GENERIC_ENHANCE_UPDATE)) {
+				f2fs_err(sbi, "Inconsistent dest blkaddr:%u, ino:%lu, ofs:%u",
+					dest, inode->i_ino, dn.ofs_in_node);
+				err = -EFSCORRUPTED;
+				goto err;
+			}
+
 			/* write dummy data page */
 			f2fs_replace_block(sbi, &dn, src, dest,
 						ni.version, false, false);