bpf: Support dual-stack sockets in bpf_tcp_check_syncookie

[platform/kernel/linux-rpi.git] / net / core / filter.c

diff --git a/net/core/filter.c b/net/core/filter.c
index a65de7a..fbde862 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -6719,24 +6719,33 @@ BPF_CALL_5(bpf_tcp_check_syncookie, struct sock *, sk, void *, iph, u32, iph_len
        if (!th->ack || th->rst || th->syn)
                return -ENOENT;
 
+       if (unlikely(iph_len < sizeof(struct iphdr)))
+               return -EINVAL;
+
        if (tcp_synq_no_recent_overflow(sk))
                return -ENOENT;
 
        cookie = ntohl(th->ack_seq) - 1;
 
-       switch (sk->sk_family) {
-       case AF_INET:
-               if (unlikely(iph_len < sizeof(struct iphdr)))
+       /* Both struct iphdr and struct ipv6hdr have the version field at the
+        * same offset so we can cast to the shorter header (struct iphdr).
+        */
+       switch (((struct iphdr *)iph)->version) {
+       case 4:
+               if (sk->sk_family == AF_INET6 && ipv6_only_sock(sk))
                        return -EINVAL;
 
                ret = __cookie_v4_check((struct iphdr *)iph, th, cookie);
                break;
 
 #if IS_BUILTIN(CONFIG_IPV6)
-       case AF_INET6:
+       case 6:
                if (unlikely(iph_len < sizeof(struct ipv6hdr)))
                        return -EINVAL;
 
+               if (sk->sk_family != AF_INET6)
+                       return -EINVAL;
+
                ret = __cookie_v6_check((struct ipv6hdr *)iph, th, cookie);
                break;
 #endif /* CONFIG_IPV6 */