From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/11878 Path: news.gmane.org!.POSTED!not-for-mail From: Rich Felker Newsgroups: gmane.linux.lib.musl.general Subject: Re: open issues Date: Wed, 30 Aug 2017 15:20:38 -0400 Message-ID: <20170830192038.GE1627@brightrain.aerifal.cx> References: <20170827043606.GQ15263@port70.net> <20170830020652.GD1627@brightrain.aerifal.cx> <1AC2E125-EED7-4EA1-AC9F-B08BA7BD494D@trust-in-soft.com> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Trace: blaine.gmane.org 1504120855 26045 195.159.176.226 (30 Aug 2017 19:20:55 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 30 Aug 2017 19:20:55 +0000 (UTC) User-Agent: Mutt/1.5.21 (2010-09-15) To: musl@lists.openwall.com Original-X-From: musl-return-11891-gllmg-musl=m.gmane.org@lists.openwall.com Wed Aug 30 21:20:51 2017 Return-path: Envelope-to: gllmg-musl@m.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by blaine.gmane.org with smtp (Exim 4.84_2) (envelope-from ) id 1dn8Xe-0006IW-UD for gllmg-musl@m.gmane.org; Wed, 30 Aug 2017 21:20:47 +0200 Original-Received: (qmail 16373 invoked by uid 550); 30 Aug 2017 19:20:51 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Original-Received: (qmail 16349 invoked from network); 30 Aug 2017 19:20:50 -0000 Content-Disposition: inline In-Reply-To: <1AC2E125-EED7-4EA1-AC9F-B08BA7BD494D@trust-in-soft.com> Original-Sender: Rich Felker Xref: news.gmane.org gmane.linux.lib.musl.general:11878 Archived-At: On Wed, Aug 30, 2017 at 08:26:46AM +0000, Pascal Cuoq wrote: > Hello, > > Punting til later due to lack of serious/any outward symptoms and lack > of any practical way to fix: > > - scanf, wrong types in va_arg > http://www.openwall.com/lists/musl/2017/04/10/3 > > Joseph Myers has pointed out to me that the POSIX chapter about > stdarg.h defines an XSI extension that allows musl's scanf to be > written just the way it is: > > http://pubs.opengroup.org/onlinepubs/009695399/basedefs/stdarg.h.html (specifically the sentence “Both types are pointers”) > > To me, this means that the issue can be dropped entirely : musl > simply needs this XSI extension, as it probably does some others. Great find. I wonder if compiler/diagnostic tool ppl are aware of this extension to the C language that XSI imposes. It definitely affects things like UBSan, and of course compilers' optimization based on assumptions that UB doesn't happen. Rich