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Date:   Thu, 6 Oct 2022 13:28:20 +0200
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Subject: Re: [PATCH] mips: allow firmware to pass RNG seed to kernel
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To:     "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc:     Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        "open list:BROADCOM NVRAM DRIVER" <linux-mips@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
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From:   =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= <philmd@fungible.com>
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On 4/10/22 00:30, Jason A. Donenfeld wrote:
> Hi Philippe,
> 
> On Tue, Oct 4, 2022 at 12:07 AM Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
>>> +       add_bootloader_randomness(rng_seed, len);
>>
>> So we call char/random code with len=0. Is it safe?
>> Maybe simply safer to check len before calling hex2bin?
> 
> add_bootloader_randomness() is safe for all input sizes, and is
> written to be callable with len=0 and have no effect. So this function
> should be good as-is; there's no need to special case an unlikely
> instance that's already handled by add_bootloader_randomness().

OK, thanks for the clarification.

Phil.