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Date: Mon, 30 Jun 2014 16:06:04 -0700
From: Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [patch] binfmt_elf.c: use get_random_int() to fix entropy
 depleting fix
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To: David Rientjes <rientjes@google.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>, Jeff Liu <jeff.liu@oracle.com>, Kees Cook <keescook@chromium.org>, linux-mm@kvack.org

On Mon, 30 Jun 2014 15:52:05 -0700 (PDT) David Rientjes <rientjes@google.com> wrote:

> The type of size_t on am33 is unsigned int for gcc major versions >= 4.
> 
> ...
>
> --- a/fs/binfmt_elf.c
> +++ b/fs/binfmt_elf.c
> @@ -155,7 +155,7 @@ static void get_atrandom_bytes(unsigned char *buf, size_t nbytes)
>  
>  	while (nbytes) {
>  		unsigned int random_variable;
> -		size_t chunk = min(nbytes, sizeof(random_variable));
> +		size_t chunk = min(nbytes, (size_t)sizeof(random_variable));
>  
>  		random_variable = get_random_int();
>  		memcpy(p, &random_variable, chunk);

I did it using min_t the other day.  I suppose using the cast is a
little clearer about the cause of the problem, but if it doesn't have a
code comment the janitors will come along and convert it to min_t.

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