[PATCH v3] f2fs: fix to detect corrupted meta ino

Chao Yu
2022-09-13T07:48:32Z

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>
---
v3:
- update commit title/message
- change logic inside f2fs_iget() rather than its caller
fs/f2fs/inode.c | 25 ++++++++++++++++++-------
1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index cde0a3dc80c3..1baac6056733 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -487,6 +487,12 @@ 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);
@@ -497,17 +503,22 @@ struct inode *f2fs_iget(struct super_block *sb, unsigned long ino)
if (!inode)
return ERR_PTR(-ENOMEM);

+ if (is_meta_ino(sbi, ino)) {
+ if (!(inode->i_state & I_NEW)) {
+ f2fs_err(sbi, "detect corrupted inode no:%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);
+ }
+ goto make_now;
+ }
+
if (!(inode->i_state & I_NEW)) {
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))
- goto make_now;
-#endif

ret = do_read_inode(inode);
if (ret)
--
2.25.1