[NETFILTER 02/04]: nf_conntrack_ipv6: fix crash when handling fragments

[Patrick McHardy <kaber@trash.net>]

[NETFILTER]: nf_conntrack_ipv6: fix crash when handling fragments

When IPv6 connection tracking splits up a defragmented packet into
its original fragments, the packets are taken from a list and are
passed to the network stack with skb->next still set. This causes
dev_hard_start_xmit to treat them as GSO fragments, resulting in
a use after free when connection tracking handles the next fragment.

Signed-off-by: Patrick McHardy <kaber@trash.net>

---
commit 19dd639a05e28a91962032bcb820437068023095
tree 163ff8250c4f4143fd6af3c43fe8df77f3970d10
parent 8d63ea0b410fed5a1d7493fa139592394ad01664
author Patrick McHardy <kaber@trash.net> Wed, 10 Jan 2007 05:43:52 +0100
committer Patrick McHardy <kaber@trash.net> Wed, 10 Jan 2007 05:43:52 +0100

 net/ipv6/netfilter/nf_conntrack_reasm.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c
index bf93c1e..7745caf 100644
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -835,6 +835,8 @@ void nf_ct_frag6_output(unsigned int hoo
 		s->nfct_reasm = skb;
 
 		s2 = s->next;
+		s->next = NULL;
+
 		NF_HOOK_THRESH(PF_INET6, hooknum, s, in, out, okfn,
 			       NF_IP6_PRI_CONNTRACK_DEFRAG + 1);
 		s = s2;