powerpc/crypto: AES-GCM mode routines for nx encryption

These routines add support for AES in GCM mode on the Power7+ CPU's
in-Nest accelerator driver.
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

drivers/crypto/nx/nx-aes-gcm.c

+/**
+ * AES GCM routines supporting the Power 7+ Nest Accelerators driver
+ *
+ * Copyright (C) 2012 International Business Machines Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 only.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * Author: Kent Yoder <yoder1@us.ibm.com>
+ */
+
+#include <crypto/internal/aead.h>
+#include <crypto/aes.h>
+#include <crypto/algapi.h>
+#include <crypto/scatterwalk.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/crypto.h>
+#include <asm/vio.h>
+
+#include "nx_csbcpb.h"
+#include "nx.h"
+
+
+static int gcm_aes_nx_set_key(struct crypto_aead *tfm,
+			      const u8           *in_key,
+			      unsigned int        key_len)
+{
+	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(&tfm->base);
+	struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
+	struct nx_csbcpb *csbcpb_aead = nx_ctx->csbcpb_aead;
+
+	nx_ctx_init(nx_ctx, HCOP_FC_AES);
+
+	switch (key_len) {
+	case AES_KEYSIZE_128:
+		NX_CPB_SET_KEY_SIZE(csbcpb, NX_KS_AES_128);
+		NX_CPB_SET_KEY_SIZE(csbcpb_aead, NX_KS_AES_128);
+		nx_ctx->ap = &nx_ctx->props[NX_PROPS_AES_128];
+		break;
+	case AES_KEYSIZE_192:
+		NX_CPB_SET_KEY_SIZE(csbcpb, NX_KS_AES_192);
+		NX_CPB_SET_KEY_SIZE(csbcpb_aead, NX_KS_AES_192);
+		nx_ctx->ap = &nx_ctx->props[NX_PROPS_AES_192];
+		break;
+	case AES_KEYSIZE_256:
+		NX_CPB_SET_KEY_SIZE(csbcpb, NX_KS_AES_256);
+		NX_CPB_SET_KEY_SIZE(csbcpb_aead, NX_KS_AES_256);
+		nx_ctx->ap = &nx_ctx->props[NX_PROPS_AES_256];
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	csbcpb->cpb.hdr.mode = NX_MODE_AES_GCM;
+	memcpy(csbcpb->cpb.aes_gcm.key, in_key, key_len);
+
+	csbcpb_aead->cpb.hdr.mode = NX_MODE_AES_GCA;
+	memcpy(csbcpb_aead->cpb.aes_gca.key, in_key, key_len);
+
+	return 0;
+}
+
+static int gcm4106_aes_nx_set_key(struct crypto_aead *tfm,
+				  const u8           *in_key,
+				  unsigned int        key_len)
+{
+	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(&tfm->base);
+	char *nonce = nx_ctx->priv.gcm.nonce;
+	int rc;
+
+	if (key_len < 4)
+		return -EINVAL;
+
+	key_len -= 4;
+
+	rc = gcm_aes_nx_set_key(tfm, in_key, key_len);
+	if (rc)
+		goto out;
+
+	memcpy(nonce, in_key + key_len, 4);
+out:
+	return rc;
+}
+
+static int gcm_aes_nx_setauthsize(struct crypto_aead *tfm,
+				  unsigned int authsize)
+{
+	if (authsize > crypto_aead_alg(tfm)->maxauthsize)
+		return -EINVAL;
+
+	crypto_aead_crt(tfm)->authsize = authsize;
+
+	return 0;
+}
+
+static int gcm4106_aes_nx_setauthsize(struct crypto_aead *tfm,
+				      unsigned int authsize)
+{
+	switch (authsize) {
+	case 8:
+	case 12:
+	case 16:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	crypto_aead_crt(tfm)->authsize = authsize;
+
+	return 0;
+}
+
+static int nx_gca(struct nx_crypto_ctx  *nx_ctx,
+		  struct aead_request   *req,
+		  u8                    *out)
+{
+	struct nx_csbcpb *csbcpb_aead = nx_ctx->csbcpb_aead;
+	int rc = -EINVAL;
+	struct scatter_walk walk;
+	struct nx_sg *nx_sg = nx_ctx->in_sg;
+
+	if (req->assoclen > nx_ctx->ap->databytelen)
+		goto out;
+
+	if (req->assoclen <= AES_BLOCK_SIZE) {
+		scatterwalk_start(&walk, req->assoc);
+		scatterwalk_copychunks(out, &walk, req->assoclen,
+				       SCATTERWALK_FROM_SG);
+		scatterwalk_done(&walk, SCATTERWALK_FROM_SG, 0);
+
+		rc = 0;
+		goto out;
+	}
+
+	nx_sg = nx_walk_and_build(nx_sg, nx_ctx->ap->sglen, req->assoc, 0,
+				  req->assoclen);
+	nx_ctx->op_aead.inlen = (nx_ctx->in_sg - nx_sg) * sizeof(struct nx_sg);
+
+	rc = nx_hcall_sync(nx_ctx, &nx_ctx->op_aead,
+			   req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP);
+	if (rc)
+		goto out;
+
+	atomic_inc(&(nx_ctx->stats->aes_ops));
+	atomic64_add(req->assoclen, &(nx_ctx->stats->aes_bytes));
+
+	memcpy(out, csbcpb_aead->cpb.aes_gca.out_pat, AES_BLOCK_SIZE);
+out:
+	return rc;
+}
+
+static int gcm_aes_nx_crypt(struct aead_request *req, int enc)
+{
+	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
+	struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
+	struct blkcipher_desc desc;
+	unsigned int nbytes = req->cryptlen;
+	int rc = -EINVAL;
+
+	if (nbytes > nx_ctx->ap->databytelen)
+		goto out;
+
+	desc.info = nx_ctx->priv.gcm.iv;
+	/* initialize the counter */
+	*(u32 *)(desc.info + NX_GCM_CTR_OFFSET) = 1;
+
+	/* For scenarios where the input message is zero length, AES CTR mode
+	 * may be used. Set the source data to be a single block (16B) of all
+	 * zeros, and set the input IV value to be the same as the GMAC IV
+	 * value. - nx_wb 4.8.1.3 */
+	if (nbytes == 0) {
+		char src[AES_BLOCK_SIZE] = {};
+		struct scatterlist sg;
+
+		desc.tfm = crypto_alloc_blkcipher("ctr(aes)", 0, 0);
+		if (IS_ERR(desc.tfm)) {
+			rc = -ENOMEM;
+			goto out;
+		}
+
+		crypto_blkcipher_setkey(desc.tfm, csbcpb->cpb.aes_gcm.key,
+			NX_CPB_KEY_SIZE(csbcpb) == NX_KS_AES_128 ? 16 :
+			NX_CPB_KEY_SIZE(csbcpb) == NX_KS_AES_192 ? 24 : 32);
+
+		sg_init_one(&sg, src, AES_BLOCK_SIZE);
+		if (enc)
+			crypto_blkcipher_encrypt_iv(&desc, req->dst, &sg,
+						    AES_BLOCK_SIZE);
+		else
+			crypto_blkcipher_decrypt_iv(&desc, req->dst, &sg,
+						    AES_BLOCK_SIZE);
+		crypto_free_blkcipher(desc.tfm);
+
+		rc = 0;
+		goto out;
+	}
+
+	desc.tfm = (struct crypto_blkcipher *)req->base.tfm;
+
+	csbcpb->cpb.aes_gcm.bit_length_aad = req->assoclen * 8;
+
+	if (req->assoclen) {
+		rc = nx_gca(nx_ctx, req, csbcpb->cpb.aes_gcm.in_pat_or_aad);
+		if (rc)
+			goto out;
+	}
+
+	if (enc)
+		NX_CPB_FDM(csbcpb) |= NX_FDM_ENDE_ENCRYPT;
+	else
+		nbytes -= AES_BLOCK_SIZE;
+
+	csbcpb->cpb.aes_gcm.bit_length_data = nbytes * 8;
+
+	rc = nx_build_sg_lists(nx_ctx, &desc, req->dst, req->src, nbytes,
+			       csbcpb->cpb.aes_gcm.iv_or_cnt);
+	if (rc)
+		goto out;
+
+	rc = nx_hcall_sync(nx_ctx, &nx_ctx->op,
+			   req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP);
+	if (rc)
+		goto out;
+
+	atomic_inc(&(nx_ctx->stats->aes_ops));
+	atomic64_add(csbcpb->csb.processed_byte_count,
+		     &(nx_ctx->stats->aes_bytes));
+
+	if (enc) {
+		/* copy out the auth tag */
+		scatterwalk_map_and_copy(csbcpb->cpb.aes_gcm.out_pat_or_mac,
+				 req->dst, nbytes,
+				 crypto_aead_authsize(crypto_aead_reqtfm(req)),
+				 SCATTERWALK_TO_SG);
+	} else if (req->assoclen) {
+		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,
+				 crypto_aead_authsize(crypto_aead_reqtfm(req)),
+				 SCATTERWALK_FROM_SG);
+		rc = memcmp(itag, otag,
+			    crypto_aead_authsize(crypto_aead_reqtfm(req))) ?
+		     -EBADMSG : 0;
+	}
+out:
+	return rc;
+}
+
+static int gcm_aes_nx_encrypt(struct aead_request *req)
+{
+	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
+	char *iv = nx_ctx->priv.gcm.iv;
+
+	memcpy(iv, req->iv, 12);
+
+	return gcm_aes_nx_crypt(req, 1);
+}
+
+static int gcm_aes_nx_decrypt(struct aead_request *req)
+{
+	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
+	char *iv = nx_ctx->priv.gcm.iv;
+
+	memcpy(iv, req->iv, 12);
+
+	return gcm_aes_nx_crypt(req, 0);
+}
+
+static int gcm4106_aes_nx_encrypt(struct aead_request *req)
+{
+	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
+	char *iv = nx_ctx->priv.gcm.iv;
+	char *nonce = nx_ctx->priv.gcm.nonce;
+
+	memcpy(iv, nonce, NX_GCM4106_NONCE_LEN);
+	memcpy(iv + NX_GCM4106_NONCE_LEN, req->iv, 8);
+
+	return gcm_aes_nx_crypt(req, 1);
+}
+
+static int gcm4106_aes_nx_decrypt(struct aead_request *req)
+{
+	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
+	char *iv = nx_ctx->priv.gcm.iv;
+	char *nonce = nx_ctx->priv.gcm.nonce;
+
+	memcpy(iv, nonce, NX_GCM4106_NONCE_LEN);
+	memcpy(iv + NX_GCM4106_NONCE_LEN, req->iv, 8);
+
+	return gcm_aes_nx_crypt(req, 0);
+}
+
+/* tell the block cipher walk routines that this is a stream cipher by
+ * setting cra_blocksize to 1. Even using blkcipher_walk_virt_block
+ * during encrypt/decrypt doesn't solve this problem, because it calls
+ * blkcipher_walk_done under the covers, which doesn't use walk->blocksize,
+ * but instead uses this tfm->blocksize. */
+struct crypto_alg nx_gcm_aes_alg = {
+	.cra_name        = "gcm(aes)",
+	.cra_driver_name = "gcm-aes-nx",
+	.cra_priority    = 300,
+	.cra_flags       = CRYPTO_ALG_TYPE_AEAD,
+	.cra_blocksize   = 1,
+	.cra_ctxsize     = sizeof(struct nx_crypto_ctx),
+	.cra_type        = &crypto_aead_type,
+	.cra_module      = THIS_MODULE,
+	.cra_list        = LIST_HEAD_INIT(nx_gcm_aes_alg.cra_list),
+	.cra_init        = nx_crypto_ctx_aes_gcm_init,
+	.cra_exit        = nx_crypto_ctx_exit,
+	.cra_aead = {
+		.ivsize      = AES_BLOCK_SIZE,
+		.maxauthsize = AES_BLOCK_SIZE,
+		.setkey      = gcm_aes_nx_set_key,
+		.setauthsize = gcm_aes_nx_setauthsize,
+		.encrypt     = gcm_aes_nx_encrypt,
+		.decrypt     = gcm_aes_nx_decrypt,
+	}
+};
+
+struct crypto_alg nx_gcm4106_aes_alg = {
+	.cra_name        = "rfc4106(gcm(aes))",
+	.cra_driver_name = "rfc4106-gcm-aes-nx",
+	.cra_priority    = 300,
+	.cra_flags       = CRYPTO_ALG_TYPE_AEAD,
+	.cra_blocksize   = 1,
+	.cra_ctxsize     = sizeof(struct nx_crypto_ctx),
+	.cra_type        = &crypto_nivaead_type,
+	.cra_module      = THIS_MODULE,
+	.cra_list        = LIST_HEAD_INIT(nx_gcm4106_aes_alg.cra_list),
+	.cra_init        = nx_crypto_ctx_aes_gcm_init,
+	.cra_exit        = nx_crypto_ctx_exit,
+	.cra_aead = {
+		.ivsize      = 8,
+		.maxauthsize = AES_BLOCK_SIZE,
+		.geniv       = "seqiv",
+		.setkey      = gcm4106_aes_nx_set_key,
+		.setauthsize = gcm4106_aes_nx_setauthsize,
+		.encrypt     = gcm4106_aes_nx_encrypt,
+		.decrypt     = gcm4106_aes_nx_decrypt,
+	}
+};