From patchwork Mon Apr 29 21:42:14 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Poirier X-Patchwork-Id: 240519 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id CBD5C2C00C4 for ; Tue, 30 Apr 2013 07:44:13 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932959Ab3D2VnA (ORCPT ); Mon, 29 Apr 2013 17:43:00 -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 Received: by mail-qa0-f50.google.com with SMTP id dx4so1284418qab.16 for ; Mon, 29 Apr 2013 14:42:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:sender:from:to:cc:subject:date:message-id:x-mailer :in-reply-to:references; bh=N6Ghj3f3LghyKEgDIE/yAC/fnxUEV9kl6eevTlxKX9M=; b=IpPQLAPrpicJ4gHwOEaeR1dDfvC2N8aUm2WLZagjh56KTUJY8Co34WH7HROTv8QJf+ WkYBArj5+KAC8TxTyEVAuvHHiRkvvhGeGnjwY1AG0m0SncCM3aYAKuXwoYmiLZc/fVZ8 oJHvTuT2RSpdnjFXXbarK9+yfFZh5IA1SLfBKHOYnPpZNc06HIeW56FPkbG+GRYAZIc1 6wHhKbcay1+2RCuV6pwI186qvCHQh3fyNJoV2uOf8J2w0wQG+A/Mw1RrDma249xoVJr1 dC+IO2Hd9s3Bp+IhfabxIEkv7qZcXomD5i1831sC5UiNKbr/8N1CamoXuT9/D2Wo28Lc luFQ== X-Received: by 10.229.138.78 with SMTP id z14mr144817qct.57.1367271758805; Mon, 29 Apr 2013 14:42:38 -0700 (PDT) Received: from d2.synalogic.ca (modemcable062.27-82-70.mc.videotron.ca. [70.82.27.62]) by mx.google.com with ESMTPSA id en8sm35926648qeb.0.2013.04.29.14.42.37 for (version=TLSv1.2 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 29 Apr 2013 14:42:38 -0700 (PDT) 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: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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 Acked-by: Eric Dumazet --- 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);