linux-kernel - Re: [tip:x86/mm] x86, mm: Use a bitfield to mask nuisance get

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]

Date:	Tue, 12 Feb 2013 09:00:30 -0800
From:	Linus Torvalds <torvalds@...ux-foundation.org>
To:	"H.J. Lu" <hjl.tools@...il.com>
Cc:	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...nel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Jamie Lokier <jamie@...reable.org>,
	ville.syrjala@...ux.intel.com, Borislav Petkov <bp@...en8.de>,
	Russell King - ARM Linux <linux@....linux.org.uk>,
	Thomas Gleixner <tglx@...utronix.de>,
	linux-tip-commits@...r.kernel.org
Subject: Re: [tip:x86/mm] x86, mm: Use a bitfield to mask nuisance get_user() warnings

On Tue, Feb 12, 2013 at 8:38 AM, H.J. Lu <hjl.tools@...il.com> wrote:
>
> Can you do something similar to what we did in glibc:

No. Because we use macros to be type-independent (i e"get_user()"
works *regardless* of type), so casting to "uintptr_t" doesn't work.
It throws away the type information, and truncates 64-bit values on
32-bit architectures.

The whole point of the bitmask thing is that it doesn't have that
issue, and gets the size correct automatically. It's not pretty, but
it allows the rest of the sources to be readable.

                Linus
--
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/