This patch implements the givencrypt function for authenc.  It simply
calls the givencrypt operation on the underlying cipher instead of encrypt.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

This patch converts the authenc algorithm over to crypto_grab_skcipher
which is a prerequisite for IV generation.

This patch also changes authenc to set its ASYNC status depending on
the ASYNC status of the underlying skcipher.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

This patch merges the common hashing code between encryption and decryption.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

This patch changes setkey to use RTA_OK to check the validity of the
setkey request.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

The ivsize should be fetched from ablkcipher, not blkcipher.

Signed-off-by: Herbert 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: Herbert 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: Herbert Xu <herbert@gondor.apana.org.au>

The previous code incorrectly included the hash in the verification which
also meant that we'd crash and burn when it comes to actually verifying
the hash since we'd go past the end of the SG list.

This patch fixes that by subtracting authsize from cryptlen at the start.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Having enckeylen as a template parameter makes it a pain for hardware
devices that implement ciphers with many key sizes since each one would
have to be registered separately.

Since the authenc algorithm is mainly used for legacy purposes where its
key is going to be constructed out of two separate keys, we can in fact
embed this value into the key itself.

This patch does this by prepending an rtnetlink header to the key that
contains the encryption key length.

Signed-off-by: Herbert 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: Herbert Xu <herbert@gondor.apana.org.au>