net/unix: fix logic about sk_peek_offset

Now send with MSG_PEEK can return data from multiple SKBs. Unfortunately we take into account the peek offset for each skb, that is wrong. We need to apply the peek offset only once. In addition, the peek offset should be used only if MSG_PEEK is set. Cc: "David S. Miller" <[email protected]> (maintainer:NETWORKING Cc: Eric Dumazet <[email protected]> (commit_signer:1/14=7%) Cc: Aaron Conole <[email protected]> Fixes: 9f389e3 ("af_unix: return data from multiple SKBs on recv() with MSG_PEEK flag") Signed-off-by: Andrey Vagin <[email protected]> Tested-by: Aaron Conole <[email protected]> Signed-off-by: David S. Miller <[email protected]>
Tkpointz · Oct 5, 2015 · e9193d6 · e9193d6
1 parent 215c90a
commit e9193d6
Showing 1 changed file with 7 additions and 5 deletions.
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
@@ -2064,6 +2064,11 @@ static int unix_stream_read_generic(struct unix_stream_read_state *state)
 		goto out;
 	}
 
+	if (flags & MSG_PEEK)
+		skip = sk_peek_offset(sk, flags);
+	else
+		skip = 0;
+
 	do {
 		int chunk;
 		struct sk_buff *skb, *last;
@@ -2112,7 +2117,6 @@ static int unix_stream_read_generic(struct unix_stream_read_state *state)
 			break;
 		}
 
-		skip = sk_peek_offset(sk, flags);
 		while (skip >= unix_skb_len(skb)) {
 			skip -= unix_skb_len(skb);
 			last = skb;
@@ -2179,14 +2183,12 @@ static int unix_stream_read_generic(struct unix_stream_read_state *state)
 			if (UNIXCB(skb).fp)
 				scm.fp = scm_fp_dup(UNIXCB(skb).fp);
 
-			if (skip) {
-				sk_peek_offset_fwd(sk, chunk);
-				skip -= chunk;
-			}
+			sk_peek_offset_fwd(sk, chunk);
 
 			if (UNIXCB(skb).fp)
 				break;
 
+			skip = 0;
 			last = skb;
 			last_len = skb->len;
 			unix_state_lock(sk);