| Message ID | 20190702120021.13096-3-nikolay@cumulusnetworks.com |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | net: bridge: fix possible stale skb pointers | expand |
Tested-by: Martin Weinelt <martin@linuxlounge.net> On 7/2/19 2:00 PM, Nikolay Aleksandrov wrote: > We get a pointer to the ipv6 hdr in br_ip6_multicast_query but we may > call pskb_may_pull afterwards and end up using a stale pointer. > So use the header directly, it's just 1 place where it's needed. > > Fixes: 08b202b67264 ("bridge br_multicast: IPv6 MLD support.") > Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> > --- > net/bridge/br_multicast.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c > index f37897e7b97b..3d8deac2353d 100644 > --- a/net/bridge/br_multicast.c > +++ b/net/bridge/br_multicast.c > @@ -1279,7 +1279,6 @@ static int br_ip6_multicast_query(struct net_bridge *br, > u16 vid) > { > unsigned int transport_len = ipv6_transport_len(skb); > - const struct ipv6hdr *ip6h = ipv6_hdr(skb); > struct mld_msg *mld; > struct net_bridge_mdb_entry *mp; > struct mld2_query *mld2q; > @@ -1323,7 +1322,7 @@ static int br_ip6_multicast_query(struct net_bridge *br, > > if (is_general_query) { > saddr.proto = htons(ETH_P_IPV6); > - saddr.u.ip6 = ip6h->saddr; > + saddr.u.ip6 = ipv6_hdr(skb)->saddr; > > br_multicast_query_received(br, port, &br->ip6_other_query, > &saddr, max_delay); >
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index f37897e7b97b..3d8deac2353d 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -1279,7 +1279,6 @@ static int br_ip6_multicast_query(struct net_bridge *br, u16 vid) { unsigned int transport_len = ipv6_transport_len(skb); - const struct ipv6hdr *ip6h = ipv6_hdr(skb); struct mld_msg *mld; struct net_bridge_mdb_entry *mp; struct mld2_query *mld2q; @@ -1323,7 +1322,7 @@ static int br_ip6_multicast_query(struct net_bridge *br, if (is_general_query) { saddr.proto = htons(ETH_P_IPV6); - saddr.u.ip6 = ip6h->saddr; + saddr.u.ip6 = ipv6_hdr(skb)->saddr; br_multicast_query_received(br, port, &br->ip6_other_query, &saddr, max_delay);
We get a pointer to the ipv6 hdr in br_ip6_multicast_query but we may call pskb_may_pull afterwards and end up using a stale pointer. So use the header directly, it's just 1 place where it's needed. Fixes: 08b202b67264 ("bridge br_multicast: IPv6 MLD support.") Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> --- net/bridge/br_multicast.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)