[PATCH 5.15.y 1/2] f2fs: fix to detect corrupted meta ino

[Sasha Levin <sashal@kernel.org>]

From: Chao Yu <chao@kernel.org>

[ Upstream commit fcc2d8cc96b2f6141bbbe5b1e8953db990794b44 ]

It is possible that ino of dirent or orphan inode is corrupted in a
fuzzed image, occasionally, if corrupted ino is equal to meta ino:
meta_ino, node_ino or compress_ino, caller of f2fs_iget() from below
call paths will get meta inode directly, it's not allowed, let's
add sanity check to detect such cases.

case #1
- recover_dentry
 - __f2fs_find_entry
 - f2fs_iget_retry

case #2
- recover_orphan_inode
 - f2fs_iget_retry

Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Stable-dep-of: 5073c66a96a9 ("f2fs: validate compress cache inode only when enabled")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/f2fs/inode.c | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index 7494a68a53196f..4a99a9eab8291d 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -496,6 +496,12 @@ static int do_read_inode(struct inode *inode)
 	return 0;
 }
 
+static bool is_meta_ino(struct f2fs_sb_info *sbi, unsigned int ino)
+{
+	return ino == F2FS_NODE_INO(sbi) || ino == F2FS_META_INO(sbi) ||
+		ino == F2FS_COMPRESS_INO(sbi);
+}
+
 struct inode *f2fs_iget(struct super_block *sb, unsigned long ino)
 {
 	struct f2fs_sb_info *sbi = F2FS_SB(sb);
@@ -507,16 +513,21 @@ struct inode *f2fs_iget(struct super_block *sb, unsigned long ino)
 		return ERR_PTR(-ENOMEM);
 
 	if (!(inode->i_state & I_NEW)) {
+		if (is_meta_ino(sbi, ino)) {
+			f2fs_err(sbi, "inaccessible inode: %lu, run fsck to repair", ino);
+			set_sbi_flag(sbi, SBI_NEED_FSCK);
+			ret = -EFSCORRUPTED;
+			trace_f2fs_iget_exit(inode, ret);
+			iput(inode);
+			return ERR_PTR(ret);
+		}
+
 		trace_f2fs_iget(inode);
 		return inode;
 	}
-	if (ino == F2FS_NODE_INO(sbi) || ino == F2FS_META_INO(sbi))
-		goto make_now;
 
-#ifdef CONFIG_F2FS_FS_COMPRESSION
-	if (ino == F2FS_COMPRESS_INO(sbi))
+	if (is_meta_ino(sbi, ino))
 		goto make_now;
-#endif
 
 	ret = do_read_inode(inode);
 	if (ret)
-- 
2.53.0