From: Peter Oskolkov <posk@google.com>
Date: Wed, 16 Jan 2019 16:47:54 +0000 (-0800)
Subject: bpf: bpf_setsockopt: reset sock dst on SO_MARK changes
X-Git-Tag: v5.0-rc3~3^2^2~5
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=f4924f24da8c7ef64195096817f3cde324091d97;p=linux.git

bpf: bpf_setsockopt: reset sock dst on SO_MARK changes

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: 8c4b4c7e9ff0 ("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
index d9076e609fca..d9ea51b47f35 100644
--- 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;