From 33ab231f83cc12d0157711bbf84e180c3be7d7bc Mon Sep 17 00:00:00 2001
From: Christian Brauner <brauner@kernel.org>
Date: Mon, 3 Jul 2023 16:49:12 +0200
Subject: [PATCH] fs: don't assume arguments are non-NULL
Git-commit: 33ab231f83cc12d0157711bbf84e180c3be7d7bc
Patch-mainline: v6.5-rc1
References: bsc#1221044 CVE-2023-52591
The helper is explicitly documented as locking zero, one, or two
arguments. While all current callers do pass non-NULL arguments there's
no need or requirement for them to do so according to the code and the
unlock_two_nondirectories() helper is pretty clear about it as well. So
only call WARN_ON_ONCE() if the checked inode is valid.
Fixes: 2454ad83b90a ("fs: Restrict lock_two_nondirectories() to non-directory inodes")
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Message-id: <20230703-vfs-rename-source-v1-2-37eebb29b65b@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Acked-by: Jan Kara <jack@suse.cz>
---
fs/inode.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c
index d37fad91c8da..8fefb69e1f84 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1156,8 +1156,10 @@ void lock_two_inodes(struct inode *inode1, struct inode *inode2,
*/
void lock_two_nondirectories(struct inode *inode1, struct inode *inode2)
{
- WARN_ON_ONCE(S_ISDIR(inode1->i_mode));
- WARN_ON_ONCE(S_ISDIR(inode2->i_mode));
+ if (inode1)
+ WARN_ON_ONCE(S_ISDIR(inode1->i_mode));
+ if (inode2)
+ WARN_ON_ONCE(S_ISDIR(inode2->i_mode));
lock_two_inodes(inode1, inode2, I_MUTEX_NORMAL, I_MUTEX_NONDIR2);
}
EXPORT_SYMBOL(lock_two_nondirectories);
--
2.35.3