linux-kernel - [PATCH 4.17 128/220] Btrfs: fix return value on rename exchange failure

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20180701160913.683036142@linuxfoundation.org>
Date:   Sun,  1 Jul 2018 18:22:32 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Filipe Manana <fdmanana@...e.com>,
        David Sterba <dsterba@...e.com>
Subject: [PATCH 4.17 128/220] Btrfs: fix return value on rename exchange failure

4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Filipe Manana <fdmanana@...e.com>

commit c5b4a50b74018b3677098151ec5f4fce07d5e6a0 upstream.

If we failed during a rename exchange operation after starting/joining a
transaction, we would end up replacing the return value, stored in the
local 'ret' variable, with the return value from btrfs_end_transaction().
So this could end up returning 0 (success) to user space despite the
operation having failed and aborted the transaction, because if there are
multiple tasks having a reference on the transaction at the time
btrfs_end_transaction() is called by the rename exchange, that function
returns 0 (otherwise it returns -EIO and not the original error value).
So fix this by not overwriting the return value on error after getting
a transaction handle.

Fixes: cdd1fedf8261 ("btrfs: add support for RENAME_EXCHANGE and RENAME_WHITEOUT")
CC: stable@...r.kernel.org # 4.9+
Signed-off-by: Filipe Manana <fdmanana@...e.com>
Reviewed-by: David Sterba <dsterba@...e.com>
Signed-off-by: David Sterba <dsterba@...e.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/btrfs/inode.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -9475,6 +9475,7 @@ static int btrfs_rename_exchange(struct
 	u64 new_idx = 0;
 	u64 root_objectid;
 	int ret;
+	int ret2;
 	bool root_log_pinned = false;
 	bool dest_log_pinned = false;

@@ -9671,7 +9672,8 @@ out_fail:
 			dest_log_pinned = false;
 		}
 	}
-	ret = btrfs_end_transaction(trans);
+	ret2 = btrfs_end_transaction(trans);
+	ret = ret ? ret : ret2;
 out_notrans:
 	if (new_ino == BTRFS_FIRST_FREE_OBJECTID)
 		up_read(&fs_info->subvol_sem);