From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-3.0 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI,T_RP_MATCHES_RCVD shortcircuit=no autolearn=ham autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 86AD41FADF for ; Thu, 11 Jan 2018 13:43:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754102AbeAKNnQ convert rfc822-to-8bit (ORCPT ); Thu, 11 Jan 2018 08:43:16 -0500 Received: from elephants.elehost.com ([216.66.27.132]:58590 "EHLO elephants.elehost.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753165AbeAKNnP (ORCPT ); Thu, 11 Jan 2018 08:43:15 -0500 X-Virus-Scanned: amavisd-new at elehost.com Received: from pangea (CPE00fc8d49d843-CM00fc8d49d840.cpe.net.cable.rogers.com [99.229.179.249]) (authenticated bits=0) by elephants.elehost.com (8.15.2/8.15.2) with ESMTPSA id w0BDhCgB049085 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Thu, 11 Jan 2018 08:43:13 -0500 (EST) (envelope-from rsbecker@nexbridge.com) From: "Randall S. Becker" To: "'Jeff King'" Cc: "'git mailing list'" References: <010f01d38a9e$a5c4f290$f14ed7b0$@nexbridge.com> <20180111063110.GB31213@sigill.intra.peff.net> In-Reply-To: <20180111063110.GB31213@sigill.intra.peff.net> Subject: RE: [PATCH] Replaced read with xread in transport-helper.c to fix SSIZE_MAX overun in t5509 Date: Thu, 11 Jan 2018 08:43:06 -0500 Message-ID: <002201d38ae2$1f9b26a0$5ed173e0$@nexbridge.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT X-Mailer: Microsoft Outlook 16.0 Content-Language: en-ca Thread-Index: AQJsSMotxvL6FxEkVCXZaKOUGVaNvAHrlxhgoi3VMxA= Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On January 11, 2018 1:31 AM Jeff King wrote" > On Thu, Jan 11, 2018 at 12:40:05AM -0500, Randall S. Becker wrote: > > diff --git a/transport-helper.c b/transport-helper.c index > > 3640804..68a4e30 100644 > > --- a/transport-helper.c > > +++ b/transport-helper.c > > @@ -1202,7 +1202,7 @@ static int udt_do_read(struct > unidirectional_transfer *t) > > return 0; /* No space for more. */ > > > > transfer_debug("%s is readable", t->src_name); > > - bytes = read(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse); > > + bytes = xread(t->src, t->buf + t->bufuse, BUFFERSIZE - > > + t->bufuse); > > if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN && > > errno != EINTR) { > > error_errno("read(%s) failed", t->src_name); > > After this patch, I don't think we can ever see any of those errno values > again, as xread() will automatically retry in such a case. > > I think that's OK. In the code before your patch, udt_do_read() would return > 0 in such a case, giving the caller the opportunity to do something besides > simply retry the read. But the only caller is udt_copy_task_routine(), which > would just loop anyway. It may be worth mentioning that in the commit > message. > > So your patch is OK. But we should probably clean up on top, like the patch > below (on top of yours; though note your patch was whitespace corrupted; > the tabs were converted to spaces). > > -- >8 -- > Subject: [PATCH] transport-helper: drop read/write errno checks > > Since we use xread() and xwrite() here, EINTR, EAGAIN, and EWOULDBLOCK > retries are already handled for us, and we will never see these errno values > ourselves. We can drop these conditions entirely, making the code easier to > follow. > > Signed-off-by: Jeff King > --- > transport-helper.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/transport-helper.c b/transport-helper.c index > d48be722a5..fc49567ac4 100644 > --- a/transport-helper.c > +++ b/transport-helper.c > @@ -1208,8 +1208,7 @@ static int udt_do_read(struct > unidirectional_transfer *t) > > transfer_debug("%s is readable", t->src_name); > bytes = xread(t->src, t->buf + t->bufuse, BUFFERSIZE - t->bufuse); > - if (bytes < 0 && errno != EWOULDBLOCK && errno != EAGAIN && > - errno != EINTR) { > + if (bytes < 0) { > error_errno("read(%s) failed", t->src_name); > return -1; > } else if (bytes == 0) { > @@ -1236,7 +1235,7 @@ static int udt_do_write(struct > unidirectional_transfer *t) > > transfer_debug("%s is writable", t->dest_name); > bytes = xwrite(t->dest, t->buf, t->bufuse); > - if (bytes < 0 && errno != EWOULDBLOCK) { > + if (bytes < 0) { > error_errno("write(%s) failed", t->dest_name); > return -1; > } else if (bytes > 0) { I'm sorry about the spaces. Still trying to get my mailer fixed so that I can get there directly from git. Thanks for the approval and subsequent. Cheers, Randall