From 1625f4529957738be7d87cf157e107b8fb9d23b9 Mon Sep 17 00:00:00 2001 From: Alexey Kodanev Date: Wed, 10 Aug 2016 13:54:57 +0300 Subject: [PATCH] net/xfrm_input: fix possible NULL deref of tunnel.ip6->parms.i_key Running LTP 'icmp-uni-basic.sh -6 -p ipcomp -m tunnel' test over openvswitch + veth can trigger kernel panic: BUG: unable to handle kernel NULL pointer dereference at 00000000000000e0 IP: [] xfrm_input+0x82/0x750 ... [] xfrm6_rcv_spi+0x1e/0x20 [] xfrm6_tunnel_rcv+0x42/0x50 [xfrm6_tunnel] [] tunnel6_rcv+0x3e/0x8c [tunnel6] [] ip6_input_finish+0xd5/0x430 [] ip6_input+0x33/0x90 [] ip6_rcv_finish+0xa5/0xb0 ... It seems that tunnel.ip6 can have garbage values and also dereferenced without a proper check, only tunnel.ip4 is being verified. Fix it by adding one more if block for AF_INET6 and initialize tunnel.ip6 with NULL inside xfrm6_rcv_spi() (which is similar to xfrm4_rcv_spi()). Fixes: 049f8e2 ("xfrm: Override skb->mark with tunnel->parm.i_key in xfrm_input") Signed-off-by: Alexey Kodanev Signed-off-by: Steffen Klassert --- net/ipv6/xfrm6_input.c | 1 + net/xfrm/xfrm_input.c | 14 +++++++------- 2 files changed, 8 insertions(+), 7 deletions(-) diff --git a/net/ipv6/xfrm6_input.c b/net/ipv6/xfrm6_input.c index 0eaab1fa6be5..00a2d40677d6 100644 --- a/net/ipv6/xfrm6_input.c +++ b/net/ipv6/xfrm6_input.c @@ -23,6 +23,7 @@ int xfrm6_extract_input(struct xfrm_state *x, struct sk_buff *skb) int xfrm6_rcv_spi(struct sk_buff *skb, int nexthdr, __be32 spi) { + XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL; XFRM_SPI_SKB_CB(skb)->family = AF_INET6; XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr); return xfrm_input(skb, nexthdr, spi, 0); diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c index 1c4ad477ce93..6e3f0254d8a1 100644 --- a/net/xfrm/xfrm_input.c +++ b/net/xfrm/xfrm_input.c @@ -207,15 +207,15 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type) family = XFRM_SPI_SKB_CB(skb)->family; /* if tunnel is present override skb->mark value with tunnel i_key */ - if (XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4) { - switch (family) { - case AF_INET: + switch (family) { + case AF_INET: + if (XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4) mark = be32_to_cpu(XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4->parms.i_key); - break; - case AF_INET6: + break; + case AF_INET6: + if (XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6) mark = be32_to_cpu(XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6->parms.i_key); - break; - } + break; } /* Allocate new secpath or COW existing one. */