linux-kernel - Re: [PATCH 10/10] drivers/char: Support compiling out the getrandom(2) syscall

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Message-ID: <54C2A931.5020308@linux.intel.com>
Date:	Fri, 23 Jan 2015 14:04:01 -0600
From:	Tom Zanussi <tom.zanussi@...ux.intel.com>
To:	Theodore Ts'o <tytso@....edu>, josh@...htriplett.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 10/10] drivers/char: Support compiling out the getrandom(2)
 syscall



On 01/23/2015 01:46 PM, Theodore Ts'o wrote:
> On Fri, Jan 23, 2015 at 12:37:16PM -0600, Tom Zanussi wrote:
>> Many embedded systems have no use for getrandom, and could benefit
>> from the size savings gained by omitting it.  Add a new EXPERT config
>> option, CONFIG_GETRANDOM_SYSCALL (default y), to support compiling it
>> out.
>
> I'm really not sure this is a good idea.  Even the tiniest embedded
> device need secure crypto.  In fact, one could argue that in the case
> of the Internet of Things, the tiniests embedded devices
> **especially** need secure crypto.  It would be.... unfortunate.... if
> the next time North Korea gets upset at the Great Satan, that all of
> our light bulbs, refridgerators, cars, heating systems, etc., are
> subject to attack.
>

Right, but not everything is networked - there are standalone embedded 
systems that could benefit from the savings.  Anyway, it's not a huge 
savings so I could just remove them to avoid the temptation...

Tom.

> We know already that home routers are running ancient kernels that are
> absolutely no protection whatever.  Is saving a few bytes really worth
> potentially opening up a similar attack vector on devices that will
> probably be at least an order of magnitude or more numerous than home
> routers, and even harder to upgrade once they get out there?
>
> And if you don't have a good random number generator, you really are
> *toast*.
>
> It's for this reason that /dev/[u]random were not eligible from being
> disabled from the very beginning; it's too much of an attractive
> nuisance to a clueless product manager....
>
> 	     	  	    	    	 - Ted
>
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