linux-kernel - [PATCH] btrfs: fix use-after-free in mount

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>] [day] [month] [year] [list]

Message-Id: <1397302393-22145-1-git-send-email-christophjaeger@linux.com>
Date:	Sat, 12 Apr 2014 13:33:13 +0200
From:	Christoph Jaeger <christophjaeger@...ux.com>
To:	clm@...com, jbacik@...com
Cc:	linux-btrfs@...r.kernel.org, linux-kernel@...r.kernel.org,
	Christoph Jaeger <christophjaeger@...ux.com>
Subject: [PATCH] btrfs: fix use-after-free in mount_subvol()

Pointer 'newargs' is used after the memory that it points to has already
been freed.

Picked up by Coverity - CID 1201425.

Fixes: 0723a0473f ("btrfs: allow mounting btrfs subvolumes with
different ro/rw options")
Signed-off-by: Christoph Jaeger <christophjaeger@...ux.com>
---
 fs/btrfs/super.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 5011aad..62f70cc 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1186,7 +1186,6 @@ static struct dentry *mount_subvol(const char *subvol_name, int flags,
 		return ERR_PTR(-ENOMEM);
 	mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name,
 			     newargs);
-	kfree(newargs);
 
 	if (PTR_RET(mnt) == -EBUSY) {
 		if (flags & MS_RDONLY) {
@@ -1196,17 +1195,22 @@ static struct dentry *mount_subvol(const char *subvol_name, int flags,
 			int r;
 			mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY, device_name,
 					     newargs);
-			if (IS_ERR(mnt))
+			if (IS_ERR(mnt)) {
+				kfree(newargs);
 				return ERR_CAST(mnt);
+			}
 
 			r = btrfs_remount(mnt->mnt_sb, &flags, NULL);
 			if (r < 0) {
 				/* FIXME: release vfsmount mnt ??*/
+				kfree(newargs);
 				return ERR_PTR(r);
 			}
 		}
 	}
 
+	kfree(newargs);
+
 	if (IS_ERR(mnt))
 		return ERR_CAST(mnt);
 
-- 
1.9.0

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/