sock_diag: fix filter code sent to userspace

Filters need to be translated to real BPF code for userland, like SO_GETFILTER.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/filter.c b/net/core/filter.c
index dad2a17..6438f29 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -778,7 +778,7 @@
 }
 EXPORT_SYMBOL_GPL(sk_detach_filter);
 
-static void sk_decode_filter(struct sock_filter *filt, struct sock_filter *to)
+void sk_decode_filter(struct sock_filter *filt, struct sock_filter *to)
 {
 	static const u16 decodes[] = {
 		[BPF_S_ALU_ADD_K]	= BPF_ALU|BPF_ADD|BPF_K,
diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c
index d5bef0b0..a0e9cf6 100644
--- a/net/core/sock_diag.c
+++ b/net/core/sock_diag.c
@@ -73,8 +73,13 @@
 		goto out;
 	}
 
-	if (filter)
-		memcpy(nla_data(attr), filter->insns, len);
+	if (filter) {
+		struct sock_filter *fb = (struct sock_filter *)nla_data(attr);
+		int i;
+
+		for (i = 0; i < filter->len; i++, fb++)
+			sk_decode_filter(&filter->insns[i], fb);
+	}
 
 out:
 	rcu_read_unlock();