linux-kernel - Re: [PATCH 0/2] Add struct crypto_alg->cra_check_optimized for crc32c

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1299751517.5263.60.camel@haakon2.linux-iscsi.org>
Date:	Thu, 10 Mar 2011 02:05:17 -0800
From:	"Nicholas A. Bellinger" <nab@...ux-iscsi.org>
To:	Herbert Xu <herbert@...dor.apana.org.au>
Cc:	linux-kernel <linux-kernel@...r.kernel.org>,
	linux-crypto <linux-crypto@...r.kernel.org>,
	James Bottomley <James.Bottomley@...e.de>,
	Christoph Hellwig <hch@....de>,
	Randy Dunlap <rdunlap@...otime.net>,
	linux-scsi <linux-scsi@...r.kernel.org>
Subject: Re: [PATCH 0/2] Add struct crypto_alg->cra_check_optimized for
	crc32c_intel

On Thu, 2011-03-10 at 01:13 -0800, Nicholas A. Bellinger wrote:
> On Thu, 2011-03-10 at 17:09 +0800, Herbert Xu wrote:
> > On Thu, Mar 10, 2011 at 12:54:24AM -0800, Nicholas A. Bellinger wrote:
> > >
> > > OK, so you mean each struct crypto_alg should define something like a
> > > 'cra_optimized_name' for which request_module(alg->cra_optimized_name)
> > > is called somewhere in libcrypto code..?
> > 
> > No, what I mean is that whenever we look up an algorithm through
> > crypto_alg_mod_lookup, we should conditionally call modprobe if
> > we havn't done so already.
> > 
> > So you just need to record one bit of info in each crypto_alg
> > object to indicate whether we have invoked modprobe.  I suggest
> > adding a CRYPTO_ALG_* bit.
> > 
> 
> Mmmm, now I am really confused, and please let me apologize in advance
> for my lack of experience with libcrypto internals..  ;)
> 
> I thought the problem was that CONFIG_CRYPTO_ALGFOO=y and
> CONFIG_CRYPTO_ALGFOO_ARCH_HW_OFFLOAD=m would cause the latter to not
> explictly call request_module() for this HW offload case..
> 
> So what I don't understand how adding a request_module() call to a list
> of known modules works when crc32c_intel.ko has not been loaded yet..?
> 
> Am I missing something obvious wrt to how crc32c.ko can tell libcrypto
> about which architecture dependent optimized modules it should load..?
> 

Just to clarify a bit on my previous comments..

We are still expecting the libcrypto consumer (iscsi_target_mod.ko) to
call the arch independent crypto_alloc_hash("crc32c", ...) in order to
have libcrypto backend logic perform a request_module() upon
architecture dependent offload modules (like crc32c_intel.ko) that
libcrypto consumers are not (and should not) be calling directly via
crypto_alloc_host("crc32c_intel", ...), correct..?

Where I am getting confused is wrt to a new crypto_alg_mod_lookup() ->
request_module() call for a struct shash_alg that has not yet be loaded
via arch/x86/crypto/crc32c-intel.c:crc32c_intel_mod_init() ->
crypto_register_shash().

Thanks,

--nab


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/