[PATCH] crypto:nx - fix nx-aes-gcm verification

[jmlatten@linux.vnet.ibm.com]

This patch fixes a bug in the nx-aes-gcm implementation.
Corrected the code so that the authtag is always verified after
decrypting and not just when there is associated data included.
Also, corrected the code to retrieve the input authtag from src
instead of dst. 

Reviewed-by: Fionnuala Gunter <fin@linux.vnet.ibm.com>
Reviewed-by: Marcelo Cerri <mhcerri@linux.vnet.ibm.com>
Signed-off-by: Joy Latten <jmlatten@linux.vnet.ibm.com>

diff --git a/drivers/crypto/nx/nx-aes-gcm.c b/drivers/crypto/nx/nx-aes-gcm.c
index 6cca6c3..eb851bb 100644
--- a/drivers/crypto/nx/nx-aes-gcm.c
+++ b/drivers/crypto/nx/nx-aes-gcm.c
@@ -243,11 +243,11 @@ static int gcm_aes_nx_crypt(struct aead_request *req, int enc)
 				 req->dst, nbytes,
 				 crypto_aead_authsize(crypto_aead_reqtfm(req)),
 				 SCATTERWALK_TO_SG);
-	} else if (req->assoclen) {
+	} else {
 		u8 *itag = nx_ctx->priv.gcm.iauth_tag;
 		u8 *otag = csbcpb->cpb.aes_gcm.out_pat_or_mac;
 
-		scatterwalk_map_and_copy(itag, req->dst, nbytes,
+		scatterwalk_map_and_copy(itag, req->src, nbytes,
 				 crypto_aead_authsize(crypto_aead_reqtfm(req)),
 				 SCATTERWALK_FROM_SG);
 		rc = memcmp(itag, otag,