bpf: Setup socket family and addresses in bpf_prog_test_run_skb

Now it's impossible to test all branches of cgroup_skb bpf program which
accesses skb->family and skb->{local,remote}_ip{4,6} fields because they
are zeroed during socket allocation. This commit fills socket family and
addresses from related fields in constructed skb.

Signed-off-by: Dmitry Yakunin <zeil@yandex-team.ru>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200803090545.82046-2-zeil@yandex-team.ru

diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index b03c469cd01fa8f22e821ae00ae764928f8a603d..736a5964fa95ea59c4978a3ba7d4b3f026c512ee 100644 (file)
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -449,6 +449,27 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
        skb->protocol = eth_type_trans(skb, current->nsproxy->net_ns->loopback_dev);
        skb_reset_network_header(skb);
 
+       switch (skb->protocol) {
+       case htons(ETH_P_IP):
+               sk->sk_family = AF_INET;
+               if (sizeof(struct iphdr) <= skb_headlen(skb)) {
+                       sk->sk_rcv_saddr = ip_hdr(skb)->saddr;
+                       sk->sk_daddr = ip_hdr(skb)->daddr;
+               }
+               break;
+#if IS_ENABLED(CONFIG_IPV6)
+       case htons(ETH_P_IPV6):
+               sk->sk_family = AF_INET6;
+               if (sizeof(struct ipv6hdr) <= skb_headlen(skb)) {
+                       sk->sk_v6_rcv_saddr = ipv6_hdr(skb)->saddr;
+                       sk->sk_v6_daddr = ipv6_hdr(skb)->daddr;
+               }
+               break;
+#endif
+       default:
+               break;
+       }
+
        if (is_l2)
                __skb_push(skb, hh_len);
        if (is_direct_pkt_access)