From: Rich Felker <dalias@libc.org>
To: musl@lists.openwall.com
Subject: Re: open issues
Date: Wed, 30 Aug 2017 15:20:38 -0400 [thread overview]
Message-ID: <20170830192038.GE1627@brightrain.aerifal.cx> (raw)
In-Reply-To: <1AC2E125-EED7-4EA1-AC9F-B08BA7BD494D@trust-in-soft.com>
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
next prev parent reply other threads:[~2017-08-30 19:20 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-27 4:36 Szabolcs Nagy
2017-08-27 6:07 ` A. Wilcox
2017-08-30 1:30 ` Rich Felker
2018-01-04 12:01 ` Alexander Monakov
2018-01-09 17:10 ` Rich Felker
2017-08-30 2:06 ` Rich Felker
2017-08-30 8:26 ` Pascal Cuoq
2017-08-30 19:20 ` Rich Felker [this message]
2017-08-30 19:37 ` Alexander Monakov
2017-08-30 20:10 ` Rich Felker
2017-08-30 19:51 ` A. Wilcox
2017-08-30 22:08 ` Rich Felker
2017-09-04 22:00 ` Szabolcs Nagy
2017-09-07 2:18 ` Rich Felker
2017-09-07 2:32 ` Rich Felker
2017-09-22 22:03 ` Szabolcs Nagy
2017-10-14 2:59 ` Rich Felker
2017-10-21 16:27 ` Rich Felker
2017-08-30 19:53 ` Stefan Sedich
2017-08-31 9:34 ` Szabolcs Nagy
2017-08-31 15:37 ` Stefan Sedich
2017-08-31 16:04 ` Rich Felker
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