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authorEric Dumazet <eric.dumazet@gmail.com>2011-08-23 19:57:05 +0000
committerDavid S. Miller <davem@davemloft.net>2011-08-24 17:49:24 -0700
commit22df13319d1fec30b8f9bcaadc295829647109bb (patch)
treeb61441ea39ac3c525746bfe8aaab9b6b5f9c6c63
parent4b275d7efa1c4412f0d572fcd7f78ed0919370b3 (diff)
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 <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/bridge/br_multicast.c8
1 files 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;