From f60e5990d9c1424af9dbca60a23ba2a1c7c1ce90 Mon Sep 17 00:00:00 2001 From: "hannes@stressinduktion.org" Date: Wed, 1 Apr 2015 17:07:44 +0200 Subject: ipv6: protect skb->sk accesses from recursive dereference inside the stack We should not consult skb->sk for output decisions in xmit recursion levels > 0 in the stack. Otherwise local socket settings could influence the result of e.g. tunnel encapsulation process. ipv6 does not conform with this in three places: 1) ip6_fragment: we do consult ipv6_npinfo for frag_size 2) sk_mc_loop in ipv6 uses skb->sk and checks if we should loop the packet back to the local socket 3) ip6_skb_dst_mtu could query the settings from the user socket and force a wrong MTU Furthermore: In sk_mc_loop we could potentially land in WARN_ON(1) if we use a PF_PACKET socket ontop of an IPv6-backed vxlan device. Reuse xmit_recursion as we are currently only interested in protecting tunnel devices. Cc: Jiri Pirko Signed-off-by: Hannes Frederic Sowa Signed-off-by: David S. Miller --- include/net/ip.h | 16 ---------------- 1 file changed, 16 deletions(-) (limited to 'include/net/ip.h') diff --git a/include/net/ip.h b/include/net/ip.h index 025c61c0dffb..6cc1eafb153a 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -453,22 +453,6 @@ static __inline__ void inet_reset_saddr(struct sock *sk) #endif -static inline int sk_mc_loop(struct sock *sk) -{ - if (!sk) - return 1; - switch (sk->sk_family) { - case AF_INET: - return inet_sk(sk)->mc_loop; -#if IS_ENABLED(CONFIG_IPV6) - case AF_INET6: - return inet6_sk(sk)->mc_loop; -#endif - } - WARN_ON(1); - return 1; -} - bool ip_call_ra_chain(struct sk_buff *skb); /* -- cgit v1.2.3-59-g8ed1b