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

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

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

+/**
+ * AES CCM 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 ccm_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;
+	default:
+		return -EINVAL;
+	}
+
+	csbcpb->cpb.hdr.mode = NX_MODE_AES_CCM;
+	memcpy(csbcpb->cpb.aes_ccm.key, in_key, key_len);
+
+	csbcpb_aead->cpb.hdr.mode = NX_MODE_AES_CCA;
+	memcpy(csbcpb_aead->cpb.aes_cca.key, in_key, key_len);
+
+	return 0;
+
+}
+
+static int ccm4309_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);
+
+	if (key_len < 3)
+		return -EINVAL;
+
+	key_len -= 3;
+
+	memcpy(nx_ctx->priv.ccm.nonce, in_key + key_len, 3);
+
+	return ccm_aes_nx_set_key(tfm, in_key, key_len);
+}
+
+static int ccm_aes_nx_setauthsize(struct crypto_aead *tfm,
+				  unsigned int authsize)
+{
+	switch (authsize) {
+	case 4:
+	case 6:
+	case 8:
+	case 10:
+	case 12:
+	case 14:
+	case 16:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	crypto_aead_crt(tfm)->authsize = authsize;
+
+	return 0;
+}
+
+static int ccm4309_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;
+}
+
+/* taken from crypto/ccm.c */
+static int set_msg_len(u8 *block, unsigned int msglen, int csize)
+{
+	__be32 data;
+
+	memset(block, 0, csize);
+	block += csize;
+
+	if (csize >= 4)
+		csize = 4;
+	else if (msglen > (unsigned int)(1 << (8 * csize)))
+		return -EOVERFLOW;
+
+	data = cpu_to_be32(msglen);
+	memcpy(block - csize, (u8 *)&data + 4 - csize, csize);
+
+	return 0;
+}
+
+/* taken from crypto/ccm.c */
+static inline int crypto_ccm_check_iv(const u8 *iv)
+{
+	/* 2 <= L <= 8, so 1 <= L' <= 7. */
+	if (1 > iv[0] || iv[0] > 7)
+		return -EINVAL;
+
+	return 0;
+}
+
+/* based on code from crypto/ccm.c */
+static int generate_b0(u8 *iv, unsigned int assoclen, unsigned int authsize,
+		       unsigned int cryptlen, u8 *b0)
+{
+	unsigned int l, lp, m = authsize;
+	int rc;
+
+	memcpy(b0, iv, 16);
+
+	lp = b0[0];
+	l = lp + 1;
+
+	/* set m, bits 3-5 */
+	*b0 |= (8 * ((m - 2) / 2));
+
+	/* set adata, bit 6, if associated data is used */
+	if (assoclen)
+		*b0 |= 64;
+
+	rc = set_msg_len(b0 + 16 - l, cryptlen, l);
+
+	return rc;
+}
+
+static int generate_pat(u8                   *iv,
+			struct aead_request  *req,
+			struct nx_crypto_ctx *nx_ctx,
+			unsigned int          authsize,
+			unsigned int          nbytes,
+			u8                   *out)
+{
+	struct nx_sg *nx_insg = nx_ctx->in_sg;
+	struct nx_sg *nx_outsg = nx_ctx->out_sg;
+	unsigned int iauth_len = 0;
+	struct vio_pfo_op *op = NULL;
+	u8 tmp[16], *b1 = NULL, *b0 = NULL, *result = NULL;
+	int rc;
+
+	/* zero the ctr value */
+	memset(iv + 15 - iv[0], 0, iv[0] + 1);
+
+	if (!req->assoclen) {
+		b0 = nx_ctx->csbcpb->cpb.aes_ccm.in_pat_or_b0;
+	} else if (req->assoclen <= 14) {
+		/* if associated data is 14 bytes or less, we do 1 GCM
+		 * operation on 2 AES blocks, B0 (stored in the csbcpb) and B1,
+		 * which is fed in through the source buffers here */
+		b0 = nx_ctx->csbcpb->cpb.aes_ccm.in_pat_or_b0;
+		b1 = nx_ctx->priv.ccm.iauth_tag;
+		iauth_len = req->assoclen;
+
+		nx_insg = nx_build_sg_list(nx_insg, b1, 16, nx_ctx->ap->sglen);
+		nx_outsg = nx_build_sg_list(nx_outsg, tmp, 16,
+					    nx_ctx->ap->sglen);
+
+		/* inlen should be negative, indicating to phyp that its a
+		 * pointer to an sg list */
+		nx_ctx->op.inlen = (nx_ctx->in_sg - nx_insg) *
+					sizeof(struct nx_sg);
+		nx_ctx->op.outlen = (nx_ctx->out_sg - nx_outsg) *
+					sizeof(struct nx_sg);
+
+		NX_CPB_FDM(nx_ctx->csbcpb) |= NX_FDM_ENDE_ENCRYPT;
+		NX_CPB_FDM(nx_ctx->csbcpb) |= NX_FDM_INTERMEDIATE;
+
+		op = &nx_ctx->op;
+		result = nx_ctx->csbcpb->cpb.aes_ccm.out_pat_or_mac;
+	} else if (req->assoclen <= 65280) {
+		/* if associated data is less than (2^16 - 2^8), we construct
+		 * B1 differently and feed in the associated data to a CCA
+		 * operation */
+		b0 = nx_ctx->csbcpb_aead->cpb.aes_cca.b0;
+		b1 = nx_ctx->csbcpb_aead->cpb.aes_cca.b1;
+		iauth_len = 14;
+
+		/* remaining assoc data must have scatterlist built for it */
+		nx_insg = nx_walk_and_build(nx_insg, nx_ctx->ap->sglen,
+					    req->assoc, iauth_len,
+					    req->assoclen - iauth_len);
+		nx_ctx->op_aead.inlen = (nx_ctx->in_sg - nx_insg) *
+						sizeof(struct nx_sg);
+
+		op = &nx_ctx->op_aead;
+		result = nx_ctx->csbcpb_aead->cpb.aes_cca.out_pat_or_b0;
+	} else {
+		/* if associated data is less than (2^32), we construct B1
+		 * differently yet again and feed in the associated data to a
+		 * CCA operation */
+		pr_err("associated data len is %u bytes (returning -EINVAL)\n",
+		       req->assoclen);
+		rc = -EINVAL;
+	}
+
+	rc = generate_b0(iv, req->assoclen, authsize, nbytes, b0);
+	if (rc)
+		goto done;
+
+	if (b1) {
+		memset(b1, 0, 16);
+		*(u16 *)b1 = (u16)req->assoclen;
+
+		scatterwalk_map_and_copy(b1 + 2, req->assoc, 0,
+					 iauth_len, SCATTERWALK_FROM_SG);
+
+		rc = nx_hcall_sync(nx_ctx, op,
+				   req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP);
+		if (rc)
+			goto done;
+
+		atomic_inc(&(nx_ctx->stats->aes_ops));
+		atomic64_add(req->assoclen, &(nx_ctx->stats->aes_bytes));
+
+		memcpy(out, result, AES_BLOCK_SIZE);
+	}
+done:
+	return rc;
+}
+
+static int ccm_nx_decrypt(struct aead_request   *req,
+			  struct blkcipher_desc *desc)
+{
+	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
+	struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
+	unsigned int nbytes = req->cryptlen;
+	unsigned int authsize = crypto_aead_authsize(crypto_aead_reqtfm(req));
+	struct nx_ccm_priv *priv = &nx_ctx->priv.ccm;
+	int rc = -1;
+
+	if (nbytes > nx_ctx->ap->databytelen)
+		return -EINVAL;
+
+	nbytes -= authsize;
+
+	/* copy out the auth tag to compare with later */
+	scatterwalk_map_and_copy(priv->oauth_tag,
+				 req->src, nbytes, authsize,
+				 SCATTERWALK_FROM_SG);
+
+	rc = generate_pat(desc->info, req, nx_ctx, authsize, nbytes,
+			  csbcpb->cpb.aes_ccm.in_pat_or_b0);
+	if (rc)
+		goto out;
+
+	rc = nx_build_sg_lists(nx_ctx, desc, req->dst, req->src, nbytes,
+			       csbcpb->cpb.aes_ccm.iv_or_ctr);
+	if (rc)
+		goto out;
+
+	NX_CPB_FDM(nx_ctx->csbcpb) &= ~NX_FDM_ENDE_ENCRYPT;
+	NX_CPB_FDM(nx_ctx->csbcpb) &= ~NX_FDM_INTERMEDIATE;
+
+	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));
+
+	rc = memcmp(csbcpb->cpb.aes_ccm.out_pat_or_mac, priv->oauth_tag,
+		    authsize) ? -EBADMSG : 0;
+out:
+	return rc;
+}
+
+static int ccm_nx_encrypt(struct aead_request   *req,
+			  struct blkcipher_desc *desc)
+{
+	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
+	struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
+	unsigned int nbytes = req->cryptlen;
+	unsigned int authsize = crypto_aead_authsize(crypto_aead_reqtfm(req));
+	int rc = -1;
+
+	if (nbytes > nx_ctx->ap->databytelen)
+		return -EINVAL;
+
+	rc = generate_pat(desc->info, req, nx_ctx, authsize, nbytes,
+			  csbcpb->cpb.aes_ccm.in_pat_or_b0);
+	if (rc)
+		goto out;
+
+	rc = nx_build_sg_lists(nx_ctx, desc, req->dst, req->src, nbytes,
+			       csbcpb->cpb.aes_ccm.iv_or_ctr);
+	if (rc)
+		goto out;
+
+	NX_CPB_FDM(csbcpb) |= NX_FDM_ENDE_ENCRYPT;
+	NX_CPB_FDM(csbcpb) &= ~NX_FDM_INTERMEDIATE;
+
+	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));
+
+	/* copy out the auth tag */
+	scatterwalk_map_and_copy(csbcpb->cpb.aes_ccm.out_pat_or_mac,
+				 req->dst, nbytes, authsize,
+				 SCATTERWALK_TO_SG);
+out:
+	return rc;
+}
+
+static int ccm4309_aes_nx_encrypt(struct aead_request *req)
+{
+	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
+	struct blkcipher_desc desc;
+	u8 *iv = nx_ctx->priv.ccm.iv;
+
+	iv[0] = 3;
+	memcpy(iv + 1, nx_ctx->priv.ccm.nonce, 3);
+	memcpy(iv + 4, req->iv, 8);
+
+	desc.info = iv;
+	desc.tfm = (struct crypto_blkcipher *)req->base.tfm;
+
+	return ccm_nx_encrypt(req, &desc);
+}
+
+static int ccm_aes_nx_encrypt(struct aead_request *req)
+{
+	struct blkcipher_desc desc;
+	int rc;
+
+	desc.info = req->iv;
+	desc.tfm = (struct crypto_blkcipher *)req->base.tfm;
+
+	rc = crypto_ccm_check_iv(desc.info);
+	if (rc)
+		return rc;
+
+	return ccm_nx_encrypt(req, &desc);
+}
+
+static int ccm4309_aes_nx_decrypt(struct aead_request *req)
+{
+	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
+	struct blkcipher_desc desc;
+	u8 *iv = nx_ctx->priv.ccm.iv;
+
+	iv[0] = 3;
+	memcpy(iv + 1, nx_ctx->priv.ccm.nonce, 3);
+	memcpy(iv + 4, req->iv, 8);
+
+	desc.info = iv;
+	desc.tfm = (struct crypto_blkcipher *)req->base.tfm;
+
+	return ccm_nx_decrypt(req, &desc);
+}
+
+static int ccm_aes_nx_decrypt(struct aead_request *req)
+{
+	struct blkcipher_desc desc;
+	int rc;
+
+	desc.info = req->iv;
+	desc.tfm = (struct crypto_blkcipher *)req->base.tfm;
+
+	rc = crypto_ccm_check_iv(desc.info);
+	if (rc)
+		return rc;
+
+	return ccm_nx_decrypt(req, &desc);
+}
+
+/* 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_ccm_aes_alg = {
+	.cra_name        = "ccm(aes)",
+	.cra_driver_name = "ccm-aes-nx",
+	.cra_priority    = 300,
+	.cra_flags       = CRYPTO_ALG_TYPE_AEAD |
+			   CRYPTO_ALG_NEED_FALLBACK,
+	.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_ccm_aes_alg.cra_list),
+	.cra_init        = nx_crypto_ctx_aes_ccm_init,
+	.cra_exit        = nx_crypto_ctx_exit,
+	.cra_aead = {
+		.ivsize      = AES_BLOCK_SIZE,
+		.maxauthsize = AES_BLOCK_SIZE,
+		.setkey      = ccm_aes_nx_set_key,
+		.setauthsize = ccm_aes_nx_setauthsize,
+		.encrypt     = ccm_aes_nx_encrypt,
+		.decrypt     = ccm_aes_nx_decrypt,
+	}
+};
+
+struct crypto_alg nx_ccm4309_aes_alg = {
+	.cra_name        = "rfc4309(ccm(aes))",
+	.cra_driver_name = "rfc4309-ccm-aes-nx",
+	.cra_priority    = 300,
+	.cra_flags       = CRYPTO_ALG_TYPE_AEAD |
+			   CRYPTO_ALG_NEED_FALLBACK,
+	.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_ccm4309_aes_alg.cra_list),
+	.cra_init        = nx_crypto_ctx_aes_ccm_init,
+	.cra_exit        = nx_crypto_ctx_exit,
+	.cra_aead = {
+		.ivsize      = 8,
+		.maxauthsize = AES_BLOCK_SIZE,
+		.setkey      = ccm4309_aes_nx_set_key,
+		.setauthsize = ccm4309_aes_nx_setauthsize,
+		.encrypt     = ccm4309_aes_nx_encrypt,
+		.decrypt     = ccm4309_aes_nx_decrypt,
+		.geniv       = "seqiv",
+	}
+};