From 4ac30c4b3659efac031818c418beb51e630d512d Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Fri, 31 May 2019 15:29:11 -0700 Subject: [PATCH 1/2] bpf: udp: ipv6: Avoid running reuseport's bpf_prog from __udp6_lib_err __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 --- 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 07fa579dfb96c..133e6370f89c4 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -515,7 +515,7 @@ int __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), inet6_sdif(skb), udptable, skb); + inet6_iif(skb), inet6_sdif(skb), udptable, NULL); if (!sk) { /* No socket for error: try tunnels before discarding */ sk = ERR_PTR(-ENOENT); From 257a525fe2e49584842c504a92c27097407f778f Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Fri, 31 May 2019 15:29:13 -0700 Subject: [PATCH 2/2] bpf: udp: Avoid calling reuseport's bpf_prog from udp_gro When the commit a6024562ffd7 ("udp: Add GRO functions to UDP socket") added udp[46]_lib_lookup_skb to the udp_gro code path, it broke the reuseport_select_sock() assumption that skb->data is pointing to the transport header. This patch follows an earlier __udp6_lib_err() fix by passing a NULL skb to avoid calling the reuseport's bpf_prog. Fixes: a6024562ffd7 ("udp: Add GRO functions to UDP socket") Cc: Tom Herbert Signed-off-by: Martin KaFai Lau Acked-by: Song Liu Signed-off-by: Alexei Starovoitov --- net/ipv4/udp.c | 6 +++++- net/ipv6/udp.c | 2 +- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 8fb250ed53d48..85db0e3d7f3f3 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -503,7 +503,11 @@ static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb, struct sock *udp4_lib_lookup_skb(struct sk_buff *skb, __be16 sport, __be16 dport) { - return __udp4_lib_lookup_skb(skb, sport, dport, &udp_table); + const struct iphdr *iph = ip_hdr(skb); + + return __udp4_lib_lookup(dev_net(skb->dev), iph->saddr, sport, + iph->daddr, dport, inet_iif(skb), + inet_sdif(skb), &udp_table, NULL); } EXPORT_SYMBOL_GPL(udp4_lib_lookup_skb); diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 133e6370f89c4..4e52c37bb8360 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -243,7 +243,7 @@ struct sock *udp6_lib_lookup_skb(struct sk_buff *skb, return __udp6_lib_lookup(dev_net(skb->dev), &iph->saddr, sport, &iph->daddr, dport, inet6_iif(skb), - inet6_sdif(skb), &udp_table, skb); + inet6_sdif(skb), &udp_table, NULL); } EXPORT_SYMBOL_GPL(udp6_lib_lookup_skb);