From 22df13319d1fec30b8f9bcaadc295829647109bb Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 23 Aug 2011 19:57:05 +0000 Subject: [PATCH] bridge: fix a possible use after free br_multicast_ipv6_rcv() can call pskb_trim_rcsum() and therefore skb head can be reallocated. Cache icmp6_type field instead of dereferencing twice the struct icmp6hdr pointer. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/bridge/br_multicast.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index 22d2d1af1c83..995cbe0ac0b2 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -1456,7 +1456,7 @@ static int br_multicast_ipv6_rcv(struct net_bridge *br, { struct sk_buff *skb2; const struct ipv6hdr *ip6h; - struct icmp6hdr *icmp6h; + u8 icmp6_type; u8 nexthdr; unsigned len; int offset; @@ -1502,9 +1502,9 @@ static int br_multicast_ipv6_rcv(struct net_bridge *br, __skb_pull(skb2, offset); skb_reset_transport_header(skb2); - icmp6h = icmp6_hdr(skb2); + icmp6_type = icmp6_hdr(skb2)->icmp6_type; - switch (icmp6h->icmp6_type) { + switch (icmp6_type) { case ICMPV6_MGM_QUERY: case ICMPV6_MGM_REPORT: case ICMPV6_MGM_REDUCTION: @@ -1544,7 +1544,7 @@ static int br_multicast_ipv6_rcv(struct net_bridge *br, BR_INPUT_SKB_CB(skb)->igmp = 1; - switch (icmp6h->icmp6_type) { + switch (icmp6_type) { case ICMPV6_MGM_REPORT: { struct mld_msg *mld; -- 2.20.1