linux-kernel - Re: [PATCH] crypto: tcrypt: add option to not exit on success

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Date:	Tue, 12 May 2009 20:37:27 -0400
From:	Neil Horman <nhorman@...driver.com>
To:	Jarod Wilson <jarod@...hat.com>
Cc:	linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org,
	Herbert Xu <herbert@...dor.apana.org.au>
Subject: Re: [PATCH] crypto: tcrypt: add option to not exit on success

On Tue, May 12, 2009 at 04:02:45PM -0400, Jarod Wilson wrote:
> On Monday 11 May 2009 10:06:32 Jarod Wilson wrote:
> > At present, the tcrypt module always exits with an -EAGAIN upon
> > successfully completing all the tests its been asked to run. There
> > are cases where it would be much simpler to verify all tests passed
> > if tcrypt simply stayed loaded (i.e. returned 0). Specifically, in
> > fips mode, all self-tests need to be run from the initrd, and its
> > much simpler to check the ret from modprobe for success than to
> > scrape dmesg. To make this doable, I've simply added a module param
> > to allow this behavior, leaving the default behavior more or less
> > the same as before, although now we're tracking all success/failure
> > rets as well.
> 
> I've been reminded that a self-test failure in fips mode means an
> immediate panic, so modprobe never sees the ret in that case, but if
> the module load failed for other reasons, a non-zero return value
> from modprobe is possible w/o traversing the code paths that trigger
> a self-test failure panic. For one, if the tcrypt module were to go
> missing for some reason, modprobe would have a non-zero ret, and the
> initrd would need to handle panicking the system.
> 
> Would there be any objections to dropping the noexit parameter
> entirely and just making its behavior the default? It would make
> all users regardless of fips mode notice failures more readily.
> 
I think thats a fine idea.  Theres no reason that a user of the tcrypt module
can't manually rmmod it when the testing is done.  Doing it that way just seems
more sane to me to begin with anyway.

Neil

> -- 
> Jarod Wilson
> jarod@...hat.com
> 
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