diff mbox series

[2/2] udf: Verify inode link counts before performing rename

Message ID 20241126123349.24798-3-jack@suse.cz (mailing list archive)
State New
Headers show
Series udf: Verify link count before updating it | expand

Commit Message

Jan Kara Nov. 26, 2024, 12:33 p.m. UTC 
During rename, we are updating link counts of various inodes either when
rename deletes target or when moving directory across directories.
Verify involved link counts are sane so that we don't trip warnings in
VFS.

Reported-by: syzbot+3ff7365dc04a6bcafa66@syzkaller.appspotmail.com
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/udf/namei.c | 10 ++++++++++
 1 file changed, 10 insertions(+)
diff mbox series

Patch

diff --git a/fs/udf/namei.c b/fs/udf/namei.c
index 2be775d30ac1..2cb49b6b0716 100644
--- a/fs/udf/namei.c
+++ b/fs/udf/namei.c
@@ -791,8 +791,18 @@  static int udf_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 			retval = -ENOTEMPTY;
 			if (!empty_dir(new_inode))
 				goto out_oiter;
+			retval = -EFSCORRUPTED;
+			if (new_inode->i_nlink != 2)
+				goto out_oiter;
 		}
+		retval = -EFSCORRUPTED;
+		if (old_dir->i_nlink < 3)
+			goto out_oiter;
 		is_dir = true;
+	} else if (new_inode) {
+		retval = -EFSCORRUPTED;
+		if (new_inode->i_nlink < 1)
+			goto out_oiter;
 	}
 	if (is_dir && old_dir != new_dir) {
 		retval = udf_fiiter_find_entry(old_inode, &dotdot_name,