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Message-ID: <tencent_706EA97643BAE446F774577CA6D6536A0305@qq.com>
From: Edward Adam Davis <eadavis@qq.com>
To: syzbot+5d34cc6474499a5ff516@syzkaller.appspotmail.com
Cc: almaz.alexandrovich@paragon-software.com,
	linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	ntfs3@lists.linux.dev,
	syzkaller-bugs@googlegroups.com
Subject: [PATCH] fs/ntfs3: dealing with situations where dir_search_u may return null
Date: Sun,  2 Jun 2024 17:56:54 +0800
In-Reply-To: <000000000000f386f90616fea5ef@google.com>
References: <000000000000f386f90616fea5ef@google.com>
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If hdr_find_e() fails to find an entry in the index buffer, dir_search_u() maybe
return NULL.
Therefore, it is necessary to add relevant judgment conditions in ntfs_lookup().

Reported-and-tested-by: syzbot+5d34cc6474499a5ff516@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
---
 fs/ntfs3/namei.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ntfs3/namei.c b/fs/ntfs3/namei.c
index 084d19d78397..293c37171d97 100644
--- a/fs/ntfs3/namei.c
+++ b/fs/ntfs3/namei.c
@@ -93,7 +93,7 @@ static struct dentry *ntfs_lookup(struct inode *dir, struct dentry *dentry,
 	 * If the MFT record of ntfs inode is not a base record, inode->i_op can be NULL.
 	 * This causes null pointer dereference in d_splice_alias().
 	 */
-	if (!IS_ERR_OR_NULL(inode) && !inode->i_op) {
+	if (IS_ERR_OR_NULL(inode) || !inode->i_op) {
 		iput(inode);
 		inode = ERR_PTR(-EINVAL);
 	}
-- 
2.43.0