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From: Kees Cook <keescook@chromium.org>
To: Daniel Axtens <dja@axtens.net>
Cc: Daniel Micay <danielmicay@gmail.com>,
	Kernel Hardening <kernel-hardening@lists.openwall.com>,
	Linux-MM <linux-mm@kvack.org>,
	kernel list <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 5/5] [RFC] mm: annotate memory allocation functions with their sizes
Date: Wed, 26 Feb 2020 13:56:56 -0800	[thread overview]
Message-ID: <202002261356.B632368@keescook> (raw)
In-Reply-To: <87wo89rieh.fsf@dja-thinkpad.axtens.net>

On Wed, Feb 26, 2020 at 05:07:18PM +1100, Daniel Axtens wrote:
> Kees Cook <keescook@chromium.org> writes:
> 
> > On Fri, Feb 07, 2020 at 03:38:22PM -0500, Daniel Micay wrote:
> >> There are some uses of ksize in the kernel making use of the real
> >> usable size of memory allocations rather than only the requested
> >> amount. It's incorrect when mixed with alloc_size markers, since if a
> >> number like 14 is passed that's used as the upper bound, rather than a
> >> rounded size like 16 returned by ksize. It's unlikely to trigger any
> >> issues with only CONFIG_FORTIFY_SOURCE, but it becomes more likely
> >> with -fsanitize=object-size or other library-based usage of
> >> __builtin_object_size.
> >
> > I think the solution here is to use a macro that does the per-bucket
> > rounding and applies them to the attributes. Keep the bucket size lists
> > in sync will likely need some BUILD_BUG_ON()s or similar.
> 
> I can have a go at this but with various other work projects it has
> unfortunately slipped way down the to-do list. So I've very happy for
> anyone else to take this and run with it.

Sounds good. I've added the above note from Micay to the KSPP bug tracker:
https://github.com/KSPP/linux/issues/5

Thanks for bringing this topic back up!

-- 
Kees Cook

      reply	other threads:[~2020-02-26 21:57 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-20  7:43 [PATCH 0/5] Annotate allocation functions with alloc_size attribute Daniel Axtens
2020-01-20  7:43 ` [PATCH 1/5] altera-stapl: altera_get_note: prevent write beyond end of 'key' Daniel Axtens
2020-01-20  7:43 ` [PATCH 2/5] [RFC] kasan: kasan_test: hide allocation sizes from the compiler Daniel Axtens
2020-01-20  7:43 ` [PATCH 3/5] [RFC] staging: rts5208: make len a u16 in rtsx_write_cfg_seq Daniel Axtens
2020-01-20  7:43 ` [PATCH 4/5] [VERY RFC] mm: kmalloc(_node): return NULL immediately for SIZE_MAX Daniel Axtens
2020-01-20 11:14   ` Michal Hocko
2020-01-20 22:51     ` Daniel Axtens
2020-01-20  7:43 ` [PATCH 5/5] [RFC] mm: annotate memory allocation functions with their sizes Daniel Axtens
2020-02-07 20:38   ` Daniel Micay
2020-02-25 18:35     ` Kees Cook
2020-02-26  6:07       ` Daniel Axtens
2020-02-26 21:56         ` Kees Cook [this message]

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