>From c99a71f05ec8643745f435c179c21dda6079c56a Mon Sep 17 00:00:00 2001 From: Nikolay Aleksandrov Date: Mon, 1 Jul 2019 20:31:14 +0300 Subject: [PATCH TEST v2] net: bridge: mcast: fix possible uses of stale pointers Signed-off-by: Nikolay Aleksandrov --- net/bridge/br_multicast.c | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index de22c8fbbb15..d3bb841942b0 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -917,6 +917,8 @@ static int br_ip4_multicast_igmp3_report(struct net_bridge *br, len = skb_transport_offset(skb) + sizeof(*ih); for (i = 0; i < num; i++) { + u16 nsrcs; + len += sizeof(*grec); if (!ip_mc_may_pull(skb, len)) return -EINVAL; @@ -924,8 +926,9 @@ static int br_ip4_multicast_igmp3_report(struct net_bridge *br, grec = (void *)(skb->data + len - sizeof(*grec)); group = grec->grec_mca; type = grec->grec_type; + nsrcs = ntohs(grec->grec_nsrcs); - len += ntohs(grec->grec_nsrcs) * 4; + len += nsrcs * 4; if (!ip_mc_may_pull(skb, len)) return -EINVAL; @@ -946,7 +949,7 @@ static int br_ip4_multicast_igmp3_report(struct net_bridge *br, src = eth_hdr(skb)->h_source; if ((type == IGMPV3_CHANGE_TO_INCLUDE || type == IGMPV3_MODE_IS_INCLUDE) && - ntohs(grec->grec_nsrcs) == 0) { + nsrcs == 0) { br_ip4_multicast_leave_group(br, port, group, vid, src); } else { err = br_ip4_multicast_add_group(br, port, group, vid, @@ -983,20 +986,22 @@ static int br_ip6_multicast_mld2_report(struct net_bridge *br, len = skb_transport_offset(skb) + sizeof(*icmp6h); for (i = 0; i < num; i++) { - __be16 *nsrcs, _nsrcs; + __be16 *_nsrcs, __nsrcs; + u16 nsrcs; nsrcs_offset = len + offsetof(struct mld2_grec, grec_nsrcs); if (skb_transport_offset(skb) + ipv6_transport_len(skb) < - nsrcs_offset + sizeof(_nsrcs)) + nsrcs_offset + sizeof(__nsrcs)) return -EINVAL; - nsrcs = skb_header_pointer(skb, nsrcs_offset, - sizeof(_nsrcs), &_nsrcs); - if (!nsrcs) + _nsrcs = skb_header_pointer(skb, nsrcs_offset, + sizeof(__nsrcs), &__nsrcs); + if (!_nsrcs) return -EINVAL; - grec_len = struct_size(grec, grec_src, ntohs(*nsrcs)); + nsrcs = ntohs(*_nsrcs); + grec_len = struct_size(grec, grec_src, nsrcs); if (!ipv6_mc_may_pull(skb, len + grec_len)) return -EINVAL; @@ -1021,7 +1026,7 @@ static int br_ip6_multicast_mld2_report(struct net_bridge *br, src = eth_hdr(skb)->h_source; if ((grec->grec_type == MLD2_CHANGE_TO_INCLUDE || grec->grec_type == MLD2_MODE_IS_INCLUDE) && - ntohs(*nsrcs) == 0) { + nsrcs == 0) { br_ip6_multicast_leave_group(br, port, &grec->grec_mca, vid, src); } else { @@ -1275,7 +1280,6 @@ 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; @@ -1319,7 +1323,7 @@ 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); -- 2.21.0