linux-kernel - Re: [RFC][PATCH 00/13] Provide saturating helpers for allocation

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Date:   Wed, 9 May 2018 09:08:24 -0700
From:   Laura Abbott <labbott@...hat.com>
To:     Kees Cook <keescook@...omium.org>,
        Matthew Wilcox <mawilcox@...rosoft.com>
Cc:     Rasmus Villemoes <linux@...musvillemoes.dk>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        kernel-hardening@...ts.openwall.com
Subject: Re: [RFC][PATCH 00/13] Provide saturating helpers for allocation

On 05/08/2018 05:42 PM, Kees Cook wrote:
> This is a stab at providing three new helpers for allocation size
> calculation:
> 
> struct_size(), array_size(), and array3_size().
> 
> These are implemented on top of Rasmus's overflow checking functions,
> and the last 8 patches are all treewide conversions of open-coded
> multiplications into the various combinations of the helper functions.
> 
> -Kees
> 
> 
Obvious question (that might indicate this deserves documentation?)

What's the difference between

kmalloc_array(cnt, sizeof(struct blah), GFP_KERNEL);

and

kmalloc(array_size(cnt, struct blah), GFP_KERNEL);


and when would you use one over the other?

Thanks,
Laura