Re: [PATCH] Make hmac algorithm selection for cookie generation dynamic

[David Miller <davem@davemloft.net>]

From: Neil Horman <nhorman@tuxdriver.com>
Date: Fri, 19 Oct 2012 11:52:06 -0400

> Currently sctp allows for the optional use of md5 of sha1 hmac algorithms to
> generate cookie values when establishing new connections via two build time
> config options.  Theres no real reason to make this a static selection.  We can
> add a sysctl that allows for the dynamic selection of these algorithms at run
> time, with the default value determined by the corresponding crypto library
> config options.  It saves us two needless configuration settings and enables the
> freedom for administrators to select which algorithm a particular system uses.
> This comes in handy when, for example running a system in FIPS mode, where use
> of md5 is disallowed, but SHA1 is permitted.
> 
> Note: This new sysctl has no corresponding socket option to select the cookie
> hmac algorithm.  I chose not to implement that intentionally, as RFC 6458
> contains no option for this value, and I opted not to pollute the socket option
> namespace.
> 
> Signed-off-by: Neil Horman <nhorman@tuxdriver.com>

Neil, please use appropriate subject prefixes in your patch
submissions.  In this case "sctp: " would have been appropriate.

Vlad, this patch looks fine to me, but I'd like you to review
it too before I apply it.

Thanks.