This patch introduces the rfc4106 wrapper for GCM just as we have an
rfc4309 wrapper for CCM.  The purpose of the wrapper is to include part
of the IV in the key so that it can be negotiated by IPsec.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This patch converts the gcm algorithm over to crypto_grab_skcipher
which is a prerequisite for IV generation.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This patch adds the gcm_base template which takes a block cipher
parameter instead of cipher.  This allows the user to specify a
specific CTR implementation.

This also fixes a leak of the cipher algorithm that was previously
looked up but never freed.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This patch adds the necessary changes for GCM to be used with async
ciphers.  This would allow it to be used with hardware devices that
support CTR.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

As discussed previously, this patch moves the basic CTR functionality
into a chainable algorithm called ctr.  The IPsec-specific variant of
it is now placed on top with the name rfc3686.

So ctr(aes) gives a chainable cipher with IV size 16 while the IPsec
variant will be called rfc3686(ctr(aes)).  This patch also adjusts
gcm accordingly.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This patch fixes the request context alignment so that it is actually
aligned to the value required by the algorithm.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

The abreq structure is currently allocated on the stack.  This is broken
if the underlying algorithm is asynchronous.  This patch changes it so
that it's taken from the private context instead which has been enlarged
accordingly.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

Unfortunately the generic chaining hasn't been ported to all architectures
yet, and notably not s390.  So this patch restores the chainging that we've
been using previously which does work everywhere.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

The scatterwalk infrastructure is used by algorithms so it needs to
move out of crypto for future users that may live in drivers/crypto
or asm/*/crypto.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This patch changes gcm/authenc to return EBADMSG instead of EINVAL for
ICV mismatches.  This convention has already been adopted by IPsec.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

The crypto_aead convention for ICVs is to include it directly in the
output.  If we decided to change this in future then we would make
the ICV (if the algorithm has an explicit one) available in the
request itself.

For now no algorithm needs this so this patch changes gcm to conform
to this convention.  It also adjusts the tcrypt aead tests to take
this into account.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

As it is authsize is an algorithm paramter which cannot be changed at
run-time.  This is inconvenient because hardware that implements such
algorithms would have to register each authsize that they support
separately.

Since authsize is a property common to all AEAD algorithms, we can add
a function setauthsize that sets it at run-time, just like setkey.

This patch does exactly that and also changes authenc so that authsize
is no longer a parameter of its template.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

Add GCM/GMAC support to cryptoapi.

GCM (Galois/Counter Mode) is an AEAD mode of operations for any block cipher
with a block size of 16.  The typical example is AES-GCM.
Signed-off-by: NMikko Herranen <mh1@iki.fi>
Reviewed-by: NMika Kukkonen <mika.kukkonen@nsn.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>