Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932976Ab3D2VnD (ORCPT ); Mon, 29 Apr 2013 17:43:03 -0400 Received: from mail-qa0-f50.google.com ([209.85.216.50]:57537 "EHLO mail-qa0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932913Ab3D2Vmj (ORCPT ); Mon, 29 Apr 2013 17:42:39 -0400 From: Benjamin Poirier To: "David S. Miller" , Eric Dumazet , Pavel Emelyanov , Cong Wang Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 3/3] unix/stream: fix peeking with an offset larger than data in queue Date: Mon, 29 Apr 2013 17:42:14 -0400 Message-Id: <1367271734-14379-3-git-send-email-bpoirier@suse.de> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1367271734-14379-1-git-send-email-bpoirier@suse.de> References: <1367271734-14379-1-git-send-email-bpoirier@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2766 Lines: 97 Currently, peeking on a unix stream socket with an offset larger than len of the data in the sk receive queue returns immediately with bogus data. This patch fixes this so that the behavior is the same as peeking with no offset on an empty queue: the caller blocks. Signed-off-by: Benjamin Poirier --- net/unix/af_unix.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 2db702d..1a02af0 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -1859,10 +1859,10 @@ out: } /* - * Sleep until data has arrive. But check for races.. + * Sleep until more data has arrived. But check for races.. */ - -static long unix_stream_data_wait(struct sock *sk, long timeo) +static long unix_stream_data_wait(struct sock *sk, long timeo, + struct sk_buff *last) { DEFINE_WAIT(wait); @@ -1871,7 +1871,7 @@ static long unix_stream_data_wait(struct sock *sk, long timeo) for (;;) { prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); - if (!skb_queue_empty(&sk->sk_receive_queue) || + if (skb_peek_tail(&sk->sk_receive_queue) != last || sk->sk_err || (sk->sk_shutdown & RCV_SHUTDOWN) || signal_pending(current) || @@ -1890,8 +1890,6 @@ static long unix_stream_data_wait(struct sock *sk, long timeo) return timeo; } - - static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg, size_t size, int flags) @@ -1936,14 +1934,12 @@ static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock, goto out; } - skip = sk_peek_offset(sk, flags); - do { int chunk; - struct sk_buff *skb; + struct sk_buff *skb, *last; unix_state_lock(sk); - skb = skb_peek(&sk->sk_receive_queue); + last = skb = skb_peek(&sk->sk_receive_queue); again: if (skb == NULL) { unix_sk(sk)->recursion_level = 0; @@ -1966,7 +1962,7 @@ again: break; mutex_unlock(&u->readlock); - timeo = unix_stream_data_wait(sk, timeo); + timeo = unix_stream_data_wait(sk, timeo, last); if (signal_pending(current) || mutex_lock_interruptible(&u->readlock)) { @@ -1980,10 +1976,13 @@ again: break; } - if (skip >= skb->len) { + skip = sk_peek_offset(sk, flags); + while (skip >= skb->len) { skip -= skb->len; + last = skb; skb = skb_peek_next(skb, &sk->sk_receive_queue); - goto again; + if (!skb) + goto again; } unix_state_unlock(sk); -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/