| Message ID | 1372841397-10873-1-git-send-email-dborkman@redhat.com |
|---|---|
| State | Rejected, archived |
| Delegated to: | David Miller |
| Headers | show |
On Wed, Jul 3, 2013 at 1:49 AM, Daniel Borkmann <dborkman@redhat.com> wrote: > The return value of nla_nest_start() is not checked, and can be NULL, > which is then being dereferenced in nla_nest_end(). Add a check to > prevent such situations. > > Signed-off-by: Daniel Borkmann <dborkman@redhat.com> > --- > On top of "net-next" tree. > > net/openvswitch/datapath.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c > index d12d6b8..51a3c66 100644 > --- a/net/openvswitch/datapath.c > +++ b/net/openvswitch/datapath.c > @@ -427,6 +427,10 @@ static int queue_userspace_packet(struct net *net, int dp_ifindex, > upcall->dp_ifindex = dp_ifindex; > > nla = nla_nest_start(user_skb, OVS_PACKET_ATTR_KEY); > + if (unlikely(!nla)) { > + err = -ENOMEM; > + goto out; > + } nla_nest_start() doesn't allocate any memory, it only fails if there isn't enough space, so the correct error code would be -EMSGSIZE. However, we just calculated the correct size a few lines earlier and we don't double check the size anywhere else, so this doesn't make a lot of sense to me. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 07/03/2013 06:32 PM, Jesse Gross wrote: > On Wed, Jul 3, 2013 at 1:49 AM, Daniel Borkmann <dborkman@redhat.com> wrote: >> The return value of nla_nest_start() is not checked, and can be NULL, >> which is then being dereferenced in nla_nest_end(). Add a check to >> prevent such situations. >> >> Signed-off-by: Daniel Borkmann <dborkman@redhat.com> >> --- >> On top of "net-next" tree. >> >> net/openvswitch/datapath.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c >> index d12d6b8..51a3c66 100644 >> --- a/net/openvswitch/datapath.c >> +++ b/net/openvswitch/datapath.c >> @@ -427,6 +427,10 @@ static int queue_userspace_packet(struct net *net, int dp_ifindex, >> upcall->dp_ifindex = dp_ifindex; >> >> nla = nla_nest_start(user_skb, OVS_PACKET_ATTR_KEY); >> + if (unlikely(!nla)) { >> + err = -ENOMEM; >> + goto out; >> + } > > nla_nest_start() doesn't allocate any memory, it only fails if there > isn't enough space, so the correct error code would be -EMSGSIZE. > However, we just calculated the correct size a few lines earlier and > we don't double check the size anywhere else, so this doesn't make a > lot of sense to me. Fair enough, please drop this then. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c index d12d6b8..51a3c66 100644 --- a/net/openvswitch/datapath.c +++ b/net/openvswitch/datapath.c @@ -427,6 +427,10 @@ static int queue_userspace_packet(struct net *net, int dp_ifindex, upcall->dp_ifindex = dp_ifindex; nla = nla_nest_start(user_skb, OVS_PACKET_ATTR_KEY); + if (unlikely(!nla)) { + err = -ENOMEM; + goto out; + } ovs_flow_to_nlattrs(upcall_info->key, user_skb); nla_nest_end(user_skb, nla);
The return value of nla_nest_start() is not checked, and can be NULL, which is then being dereferenced in nla_nest_end(). Add a check to prevent such situations. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> --- On top of "net-next" tree. net/openvswitch/datapath.c | 4 ++++ 1 file changed, 4 insertions(+)