netdev - Re: [PATCH] net: net_secret should not depend on TCP

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Message-ID: <1380037587.3165.82.camel@edumazet-glaptop>
Date:	Tue, 24 Sep 2013 08:46:27 -0700
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Hannes Frederic Sowa <hannes@...essinduktion.org>
Cc:	Tom Herbert <therbert@...gle.com>, davem@...emloft.net,
	netdev@...r.kernel.org, jesse.brandeburg@...el.com
Subject: Re: [PATCH] net: net_secret should not depend on TCP

On Tue, 2013-09-24 at 17:28 +0200, Hannes Frederic Sowa wrote:

> But couldn't it be that get_random_bytes always returns 0 and we won't make
> any progress here. Does the reseed happen from irq context or from softirqs? I
> always thought it would be from a softirq (which could be blocked).

Really if get_random_bytes() could return 0 forever I think we would
have a big problem with its implementation and documentation :

/*
 * This function is the exported kernel interface.  It returns some
 * number of good random numbers, suitable for key generation, seeding
 * TCP sequence numbers, etc.  It does not use the hw random number
 * generator, if available; use get_random_bytes_arch() for that.
 */
void get_random_bytes(void *buf, int nbytes)
{
        extract_entropy(&nonblocking_pool, buf, nbytes, 0, 0);
}
EXPORT_SYMBOL(get_random_bytes);




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