From 3a7ef457e85173a5b9ec7a03016db5a57b717b33 Mon Sep 17 00:00:00 2001 From: Stefano Brivio Date: Tue, 13 Aug 2019 00:46:01 +0200 Subject: ipv6: Fix return value of ipv6_mc_may_pull() for malformed packets Commit ba5ea614622d ("bridge: simplify ip_mc_check_igmp() and ipv6_mc_check_mld() calls") replaces direct calls to pskb_may_pull() in br_ipv6_multicast_mld2_report() with calls to ipv6_mc_may_pull(), that returns -EINVAL on buffers too short to be valid IPv6 packets, while maintaining the previous handling of the return code. This leads to the direct opposite of the intended effect: if the packet is malformed, -EINVAL evaluates as true, and we'll happily proceed with the processing. Return 0 if the packet is too short, in the same way as this was fixed for IPv4 by commit 083b78a9ed64 ("ip: fix ip_mc_may_pull() return value"). I don't have a reproducer for this, unlike the one referred to by the IPv4 commit, but this is clearly broken. Fixes: ba5ea614622d ("bridge: simplify ip_mc_check_igmp() and ipv6_mc_check_mld() calls") Signed-off-by: Stefano Brivio Acked-by: Guillaume Nault Signed-off-by: David S. Miller --- include/net/addrconf.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/net/addrconf.h b/include/net/addrconf.h index becdad576859..3f62b347b04a 100644 --- a/include/net/addrconf.h +++ b/include/net/addrconf.h @@ -206,7 +206,7 @@ static inline int ipv6_mc_may_pull(struct sk_buff *skb, unsigned int len) { if (skb_transport_offset(skb) + ipv6_transport_len(skb) < len) - return -EINVAL; + return 0; return pskb_may_pull(skb, len); } -- cgit v1.2.3