From f9bbc770576a66efcd5dac7876baabcedfcd758f Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Fri, 31 May 2019 15:29:11 -0700 Subject: [PATCH] bpf: udp: ipv6: Avoid running reuseport's bpf_prog from __udp6_lib_err commit 4ac30c4b3659efac031818c418beb51e630d512d upstream. __udp6_lib_err() may be called when handling icmpv6 message. For example, the icmpv6 toobig(type=2). __udp6_lib_lookup() is then called which may call reuseport_select_sock(). reuseport_select_sock() will call into a bpf_prog (if there is one). reuseport_select_sock() is expecting the skb->data pointing to the transport header (udphdr in this case). For example, run_bpf_filter() is pulling the transport header. However, in the __udp6_lib_err() path, the skb->data is pointing to the ipv6hdr instead of the udphdr. One option is to pull and push the ipv6hdr in __udp6_lib_err(). Instead of doing this, this patch follows how the original commit 538950a1b752 ("soreuseport: setsockopt SO_ATTACH_REUSEPORT_[CE]BPF") was done in IPv4, which has passed a NULL skb pointer to reuseport_select_sock(). Fixes: 538950a1b752 ("soreuseport: setsockopt SO_ATTACH_REUSEPORT_[CE]BPF") Cc: Craig Gallek Signed-off-by: Martin KaFai Lau Acked-by: Song Liu Acked-by: Craig Gallek Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Signed-off-by: Greg Kroah-Hartman --- net/ipv6/udp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index fa743776c459..9f7bfeb90fb0 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -506,7 +506,7 @@ void __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt, struct net *net = dev_net(skb->dev); sk = __udp6_lib_lookup(net, daddr, uh->dest, saddr, uh->source, - inet6_iif(skb), 0, udptable, skb); + inet6_iif(skb), 0, udptable, NULL); if (!sk) { __ICMP6_INC_STATS(net, __in6_dev_get(skb->dev), ICMP6_MIB_INERRORS); -- 2.20.1