220 5325 article Path: news.gmane.org!not-for-mail From: Ville Voutilainen Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Remove filesystem unique_path Date: Sun, 7 Jul 2013 14:09:41 +0300 Lines: 88 Approved: news@gmane.org Message-ID: References: <4b95e9b9-d5cc-4314-bd32-1e09fe35ed9d@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary=047d7b6da616f243fe04e0e9f600 X-Trace: ger.gmane.org 1373195385 28775 80.91.229.3 (7 Jul 2013 11:09:45 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 7 Jul 2013 11:09:45 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBC5JHI7A7ALRB5UY4WHAKGQEOZ7B7DY@isocpp.org Sun Jul 07 13:09:47 2013 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-gh0-f199.google.com ([209.85.160.199]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Uvmqd-0000K0-IK for gclcip-std-proposals@m.gmane.org; Sun, 07 Jul 2013 13:09:43 +0200 Original-Received: by mail-gh0-f199.google.com with SMTP id g14sf4192839ghb.6 for ; Sun, 07 Jul 2013 04:09:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-beenthere:mime-version:in-reply-to:references:date:message-id :subject:from:to:x-original-sender:x-original-authentication-results :reply-to:precedence:mailing-list:list-id:x-google-group-id :list-post:list-help:list-archive:list-subscribe:list-unsubscribe :content-type; bh=u8RYVFfChpEFx6cWV0GAR0lJzK08mRXgdZ5SwQLWi2k=; b=fnltJvvHtNtV8HQVioFaoorYWshY2OndwedTjdTSx1mtzxQiufNxH65+nXbtXMX6hN M88cr6LV40COmmLWBq0YBLTf/SbNXexezxSHpxtQZLLgRzYhf3+kdS79kE3/3P7XqG6b kdm0kVJWvuqp/AXnd31ABm5A4KDoM2ec37rJ844MAzxkVgUsN7RdoA2zvigYAgBaBb6n gstU/LHnaBWVLZyEPUNEB2Ur5DFJevH3un7xdzapTC2DCytNpwAQwM4f98O0HjufY6MC pHpM1E7XWukwBU2qdjDYt48SNy3Mi1pJPWHvWhsypDcEPKFRscIbDZwhpzCS6QHHQ7TX dWQQ== X-Received: by 10.224.55.200 with SMTP id v8mr20193067qag.7.1373195382457; Sun, 07 Jul 2013 04:09:42 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.49.48.115 with SMTP id k19ls1497637qen.5.gmail; Sun, 07 Jul 2013 04:09:42 -0700 (PDT) X-Received: by 10.229.10.65 with SMTP id o1mr2762645qco.87.1373195382032; Sun, 07 Jul 2013 04:09:42 -0700 (PDT) Original-Received: from mail-qa0-x22f.google.com (mail-qa0-x22f.google.com [2607:f8b0:400d:c00::22f]) by mx.google.com with ESMTPS id r10si3557150qai.77.2013.07.07.04.09.42 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sun, 07 Jul 2013 04:09:42 -0700 (PDT) Received-SPF: pass (google.com: domain of ville.voutilainen@gmail.com designates 2607:f8b0:400d:c00::22f as permitted sender) client-ip=2607:f8b0:400d:c00::22f; Original-Received: by mail-qa0-f47.google.com with SMTP id i13so5243433qae.6 for ; Sun, 07 Jul 2013 04:09:42 -0700 (PDT) X-Received: by 10.49.95.97 with SMTP id dj1mr11477266qeb.46.1373195381914; Sun, 07 Jul 2013 04:09:41 -0700 (PDT) Original-Received: by 10.224.52.71 with HTTP; Sun, 7 Jul 2013 04:09:41 -0700 (PDT) In-Reply-To: <4b95e9b9-d5cc-4314-bd32-1e09fe35ed9d@isocpp.org> X-Original-Sender: ville.voutilainen@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of ville.voutilainen@gmail.com designates 2607:f8b0:400d:c00::22f as permitted sender) smtp.mail=ville.voutilainen@gmail.com; dkim=pass header.i=@gmail.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:5325 Archived-At: --047d7b6da616f243fe04e0e9f600 Content-Type: text/plain; charset=ISO-8859-1 On 7 July 2013 13:59, wrote: > I was surprised when I looked at the file system proposal and found > unique_path. > > unique_path is similar to the POSIX tempnam[1] function that was marked as > obsolecent in POSIX 2008 and tmpfile, mkdtemp and mkstemp recommended in > it's place. Why incorporate the mistakes from posix in C++? > > The problem with unique_path is that there is a window of opportunity > between the check that the path name is unique and the time when it is used. > That window can be used by malware -- and in the case of tempnam it have > been used by malware. > > I thus propose that 15.38 is removed. > > This is a known issue, but the current plan is to include unique_path and document the race possibility. That means that users need to be careful where and when to use unique_path. The function itself is still useful, but it can't be used under the circumstances under which tmpnam() is unsafe. Having a mkstemp/mkdtemp equivalent is something that should probably be handled in subsequent revisions of the filesystem library. -- --- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. To unsubscribe from this group and stop receiving emails from it, send an email to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposals/. --047d7b6da616f243fe04e0e9f600 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable



On 7 July 2013 13:59, <magfr@lysator.liu.se> wro= te:
I was surprised when I looked at the file system proposal and found unique_= path.

unique_path is similar to the POSIX tempnam[1] function that w= as marked as obsolecent in POSIX 2008 and tmpfile, mkdtemp and mkstemp reco= mmended in it's place. Why incorporate the mistakes from posix in C++?<= br>
The problem with unique_path is that there is a window of opportunity b= etween the check that the path name is unique and the time when it is used.=
That window can be used by malware -- and in the case of tempnam it hav= e been used by malware.

I thus propose that 15.38 is removed.


This is= a known issue, but the current plan is to include unique_path and document= the race possibility.
That means that users need to be careful where and when to use u= nique_path. The function itself
is still useful, but it can't be use= d under the circumstances under which tmpnam() is unsafe.

Having a mkstemp/mkdtemp equivalent is something that should probably = be handled in subsequent
revisions of the filesystem library.=

--
 
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