crypto: ccp - Ignore tag length when decrypting GCM ciphertext

commit e2664ecb upstream.

AES GCM input buffers for decryption contain AAD+CTEXT+TAG. Only
decrypt the ciphertext, and use the tag for comparison.

Fixes: 36cf515b ("crypto: ccp - Enable support for AES GCM on v5 CCPs")
Cc: <stable@vger.kernel.org>
Signed-off-by: Gary R Hook <gary.hook@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/crypto/ccp/ccp-ops.c

@@ -785,8 +785,7 @@ static int ccp_run_aes_gcm_cmd(struct ccp_cmd_queue *cmd_q,
 		while (src.sg_wa.bytes_left) {
 			ccp_prepare_data(&src, &dst, &op, AES_BLOCK_SIZE, true);
 			if (!src.sg_wa.bytes_left) {
-				unsigned int nbytes = aes->src_len
-						      % AES_BLOCK_SIZE;
+				unsigned int nbytes = ilen % AES_BLOCK_SIZE;
 
 				if (nbytes) {
 					op.eom = 1;