Christoph Jaeger
2014-Apr-12 11:33 UTC
[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@linux.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