| Date | Wed, 28 Sep 2011 15:02:34 -0700 | From | Greg KH <> | Subject | [190/244] bridge: fix a possible use after free |
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3.0-stable review patch. If anyone has any objections, please let us know.
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From: Eric Dumazet <eric.dumazet@gmail.com>
[ Upstream commit 22df13319d1fec30b8f9bcaadc295829647109bb ]
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> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> --- net/bridge/br_multicast.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
--- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -1456,7 +1456,7 @@ static int br_multicast_ipv6_rcv(struct { 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 __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 BR_INPUT_SKB_CB(skb)->igmp = 1; - switch (icmp6h->icmp6_type) { + switch (icmp6_type) { case ICMPV6_MGM_REPORT: { struct mld_msg *mld;
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