Re: [PATCH 2/4] lib/vsprintf.c: also improve sanity check in bstr_printf()

From: Kees Cook
Date: Mon Sep 28 2015 - 18:31:11 EST


On Fri, Sep 25, 2015 at 10:41 AM, Rasmus Villemoes
<linux@xxxxxxxxxxxxxxxxxx> wrote:
> Quoting from 2aa2f9e21e4e ("lib/vsprintf.c: improve sanity check in
> vsnprintf()"):
>
> On 64 bit, size may very well be huge even if bit 31 happens to be 0.
> Somehow it doesn't feel right that one can pass a 5 GiB buffer but not a
> 3 GiB one. So cap at INT_MAX as was probably the intention all along.
> This is also the made-up value passed by sprintf and vsprintf.
>
> I should have seen this copy-pasted instance back then, but let's just
> do it now.
>
> Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>

Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>

-Kees

--
Kees Cook
Chrome OS Security
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