linux-kernel - Re: [PATCH 16/16] fix handling of integer constant expressions

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <c18a28cc8094adeac7ff98652609a8cb@kernel.crashing.org>
Date:	Sun, 24 Jun 2007 21:09:28 +0200
From:	Segher Boessenkool <segher@...nel.crashing.org>
To:	Al Viro <viro@....linux.org.uk>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, linux-sparse@...r.kernel.org
Subject: Re: [PATCH 16/16] fix handling of integer constant expressions

>> If I understand correctly what bugs you are talking about,
>> most (all?) of those were solved in the dark ages already
>> (i.e., the 3.x series).
>
> Alas, no.  gcc is amazingly (and inconsistently) sloppy about the
> things it accepts as integer constant expressions.

Ah yes, now I see what you were talking about.  Most of this
is well-known, but feel free to file more PRs :-)

>>> It certainly is not a valid C
>>
>> Why not?  Nothing in the C standard says all your externs
>> have to be defined in some other translation unit you link
>> with AFAIK.
>
> It's not about externs.  It's about things like
>
> unsigned n;
> int a[] = {[n - n + n - n] = 1};
>
> And yes, gcc does eat that.

Yeah.

> With -pedantic -std=c99, at that.
> However,
>
> unsigned n;
> int a[] = {[n + n - n - n] = 1};
>
> gets you error: nonconstant array index in initializer
>
> And that's 4.1, not 3.x...

Why are you using such an ancient compiler? :-)
(Not that it is fixed in the current release though).


Segher

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/