bpf: bpf_setsockopt: reset sock dst on SO_MARK changes

Peter Oskolkov · borkmann · commit f4924f24da8c · 2019-01-18T00:27:47.000+01:00
In sock_setsockopt() (net/core/sock.h), when SO_MARK option is used to change sk_mark, sk_dst_reset(sk) is called. The same should be done in bpf_setsockopt(). Fixes: 8c4b4c7 ("bpf: Add setsockopt helper function to bpf") Reported-by: Maciej Żenczykowski <maze@google.com> Signed-off-by: Peter Oskolkov <posk@google.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Reviewed-by: Maciej Żenczykowski <maze@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
diff --git a/net/core/filter.c b/net/core/filter.c
@@ -4132,7 +4132,10 @@ BPF_CALL_5(bpf_setsockopt, struct bpf_sock_ops_kern *, bpf_sock,
 			sk->sk_rcvlowat = val ? : 1;
 			break;
 		case SO_MARK:
-			sk->sk_mark = val;
+			if (sk->sk_mark != val) {
+				sk->sk_mark = val;
+				sk_dst_reset(sk);
+			}
 			break;
 		default:
 			ret = -EINVAL;
