From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josh Durgin Subject: Re: [PATCH 5/6] rbd: fix leak of format 2 snapshot names Date: Mon, 29 Apr 2013 08:16:46 -0700 Message-ID: <517E8EDE.1020106@inktank.com> References: <517A6D39.80000@inktank.com> <517A6DD1.2080102@inktank.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pb0-f45.google.com ([209.85.160.45]:59061 "EHLO mail-pb0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751225Ab3D2PQ1 (ORCPT ); Mon, 29 Apr 2013 11:16:27 -0400 Received: by mail-pb0-f45.google.com with SMTP id ro2so2033786pbb.4 for ; Mon, 29 Apr 2013 08:16:27 -0700 (PDT) In-Reply-To: <517A6DD1.2080102@inktank.com> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Alex Elder Cc: ceph-devel@vger.kernel.org Reviewed-by: Josh Durgin On 04/26/2013 05:06 AM, Alex Elder wrote: > When the snapshot context for an rbd device gets updated (or the > initial one is recorded) a a list of snapshot structures is created > to represent them, one entry per snapshot. Each entry includes a > dynamically-allocated copy of the snapshot name. > > Currently the name is allocated in rbd_snap_create(), as a duplicate > of the passed-in name. > > For format 1 images, the snapshot name provided is just a pointer to > an existing name. But for format 2 images, the passed-in name is > already dynamically allocated, and in the the process of duplicating > it here we are leaking the passed-in name. > > Fix this by dynamically allocating the name for format 1 snapshots > also, and then stop allocating a duplicate in rbd_snap_create(). > > Change rbd_dev_v1_snap_info() so none of its parameters is > side-effected unless it's going to return success. > > This is part of: > http://tracker.ceph.com/issues/4803 > > Signed-off-by: Alex Elder > --- > drivers/block/rbd.c | 27 ++++++++++++--------------- > 1 file changed, 12 insertions(+), 15 deletions(-) > > diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c > index 916741b..2b5ba50 100644 > --- a/drivers/block/rbd.c > +++ b/drivers/block/rbd.c > @@ -3427,30 +3427,23 @@ static struct rbd_snap *rbd_snap_create(struct > rbd_device *rbd_dev, > u64 snap_features) > { > struct rbd_snap *snap; > - int ret; > > snap = kzalloc(sizeof (*snap), GFP_KERNEL); > if (!snap) > return ERR_PTR(-ENOMEM); > > - ret = -ENOMEM; > - snap->name = kstrdup(snap_name, GFP_KERNEL); > - if (!snap->name) > - goto err; > - > + snap->name = snap_name; > snap->id = snap_id; > snap->size = snap_size; > snap->features = snap_features; > > return snap; > - > -err: > - kfree(snap->name); > - kfree(snap); > - > - return ERR_PTR(ret); > } > > +/* > + * Returns a dynamically-allocated snapshot name if successful, or a > + * pointer-coded error otherwise. > + */ > static char *rbd_dev_v1_snap_info(struct rbd_device *rbd_dev, u32 which, > u64 *snap_size, u64 *snap_features) > { > @@ -3458,15 +3451,19 @@ static char *rbd_dev_v1_snap_info(struct > rbd_device *rbd_dev, u32 which, > > rbd_assert(which < rbd_dev->header.snapc->num_snaps); > > - *snap_size = rbd_dev->header.snap_sizes[which]; > - *snap_features = 0; /* No features for v1 */ > - > /* Skip over names until we find the one we are looking for */ > > snap_name = rbd_dev->header.snap_names; > while (which--) > snap_name += strlen(snap_name) + 1; > > + snap_name = kstrdup(snap_name, GFP_KERNEL); > + if (!snap_name); > + return ERR_PTR(-ENOMEM); > + > + *snap_size = rbd_dev->header.snap_sizes[which]; > + *snap_features = 0; /* No features for v1 */ > + > return snap_name; > } >