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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <mawilcox@microsoft.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Matthew Wilcox <willy@infradead.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-mm <linux-mm@kvack.org>,
	Kernel Hardening <kernel-hardening@lists.openwall.com>
Subject: Re: [PATCH v3 00/16] Provide saturating helpers for allocation
Date: Thu, 31 May 2018 19:54:18 -0500	[thread overview]
Message-ID: <CA+55aFzjt27tDoxU=iVo7N3cR_nVSRm5+nvTZg=+t2A4k_yNwA@mail.gmail.com> (raw)
In-Reply-To: <20180601004233.37822-1-keescook@chromium.org>

On Thu, May 31, 2018 at 7:43 PM Kees Cook <keescook@chromium.org> wrote:
>
> So, while nothing does:
>     kmalloc_array(a, b, ...) -> kmalloc(array_size(a, b), ...)
> the treewide changes DO perform changes like this:
>     kmalloc(a * b, ...) -> kmalloc(array_size(a, b), ...)

Ugh. I really really still absolutely despise this.

Why can't you just have a separate set of coccinelle scripts that do
the simple and clean cases?

So *before* doing any array_size() conversions, just do

    kzalloc(a*b, ...) -> kcalloc(a, b, ...)
    kmalloc(a*b,..) -> kmalloc_array(a,b, ...)

and the obvious variations on that (devm_xyz() has all the same helpers).

Only after doing the ones that don't have the nice obvious helpers, do
the remaining ones with array_size(), ie

    *alloc(a*b, ..) -> *alloc(array_size(a,b), ...)

because that really makes for much less legible code.

Hmm?

            Linus

  parent reply	other threads:[~2018-06-01  0:54 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-01  0:42 Kees Cook
2018-06-01  0:42 ` [PATCH v3 01/16] compiler.h: enable builtin overflow checkers and add fallback code Kees Cook
2018-06-01  0:42 ` [PATCH v3 02/16] lib: add runtime test of check_*_overflow functions Kees Cook
2018-06-01  0:42 ` [PATCH v3 03/16] lib: overflow: Report test failures Kees Cook
2018-06-01  0:42 ` [PATCH v3 04/16] overflow.h: Add allocation size calculation helpers Kees Cook
2018-06-01  0:42 ` [PATCH v3 05/16] lib: overflow: Add memory allocation overflow tests Kees Cook
2018-06-01 10:18   ` Andy Shevchenko
2018-06-01  0:42 ` [PATCH v3 06/16] mm: Use overflow helpers in kmalloc_array*() Kees Cook
2018-06-01  0:42 ` [PATCH v3 07/16] mm: Use overflow helpers in kvmalloc() Kees Cook
2018-06-01  0:42 ` [PATCH v3 08/16] device: Use overflow helpers for devm_kmalloc() Kees Cook
2018-06-01  0:42 ` [PATCH v3 09/16] treewide: Use struct_size() for kmalloc()-family Kees Cook
2018-06-01  0:42 ` [PATCH v3 10/16] treewide: Use struct_size() for vmalloc()-family Kees Cook
2018-06-01  0:42 ` [PATCH v3 11/16] treewide: Use struct_size() for devm_kmalloc() and friends Kees Cook
2018-06-01  0:42 ` [PATCH v3 12/16] treewide: Use array_size() for kmalloc()-family Kees Cook
2018-07-01  8:46   ` SF Markus Elfring
2018-07-01  9:03     ` Julia Lawall
2018-07-01  9:22       ` SF Markus Elfring
2018-06-01  0:42 ` [PATCH v3 13/16] treewide: Use array_size() for kmalloc()-family, leftovers Kees Cook
2018-06-01  0:42 ` [PATCH v3 14/16] treewide: Use array_size() for vmalloc() Kees Cook
2018-06-01  0:42 ` [PATCH v3 15/16] treewide: Use array_size() for devm_*alloc()-like Kees Cook
2018-06-01  0:42 ` [PATCH v3 16/16] treewide: Use array_size() for devm_*alloc()-like, leftovers Kees Cook
2018-06-01  0:54 ` Linus Torvalds [this message]
2018-06-01  4:18   ` [PATCH v3 00/16] Provide saturating helpers for allocation Kees Cook
2018-06-01 13:50 Peter Rosin

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