From acf568ee859f098279eadf551612f103afdacb4e Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Fri, 15 Dec 2017 16:40:44 +1100 Subject: xfrm: Reinject transport-mode packets through tasklet This is an old bugbear of mine: https://www.mail-archive.com/netdev@vger.kernel.org/msg03894.html By crafting special packets, it is possible to cause recursion in our kernel when processing transport-mode packets at levels that are only limited by packet size. The easiest one is with DNAT, but an even worse one is where UDP encapsulation is used in which case you just have to insert an UDP encapsulation header in between each level of recursion. This patch avoids this problem by reinjecting tranport-mode packets through a tasklet. Fixes: b05e106698d9 ("[IPV4/6]: Netfilter IPsec input hooks") Signed-off-by: Herbert Xu Signed-off-by: Steffen Klassert --- net/ipv6/xfrm6_input.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'net/ipv6/xfrm6_input.c') diff --git a/net/ipv6/xfrm6_input.c b/net/ipv6/xfrm6_input.c index fe04e23af986..841f4a07438e 100644 --- a/net/ipv6/xfrm6_input.c +++ b/net/ipv6/xfrm6_input.c @@ -32,6 +32,14 @@ int xfrm6_rcv_spi(struct sk_buff *skb, int nexthdr, __be32 spi, } EXPORT_SYMBOL(xfrm6_rcv_spi); +static int xfrm6_transport_finish2(struct net *net, struct sock *sk, + struct sk_buff *skb) +{ + if (xfrm_trans_queue(skb, ip6_rcv_finish)) + __kfree_skb(skb); + return -1; +} + int xfrm6_transport_finish(struct sk_buff *skb, int async) { struct xfrm_offload *xo = xfrm_offload(skb); @@ -56,7 +64,7 @@ int xfrm6_transport_finish(struct sk_buff *skb, int async) NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, dev_net(skb->dev), NULL, skb, skb->dev, NULL, - ip6_rcv_finish); + xfrm6_transport_finish2); return -1; } -- cgit v1.2.3-70-g09d2