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>
Signed-off-by: Chris Mason <clm@fb.com>
This commit is contained in:
Christoph Jaeger 2014-04-12 13:33:13 +02:00 committed by Chris Mason
parent e4fbaee292
commit 0040e606e3

View file

@ -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);