crypto: ccp - CCP AES CMAC mode crypto API support

These routines provide crypto API support for the CMAC mode of AES
on the AMD CCP.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/ccp/ccp-crypto-aes-cmac.c

+/*
+ * AMD Cryptographic Coprocessor (CCP) AES CMAC crypto API support
+ *
+ * Copyright (C) 2013 Advanced Micro Devices, Inc.
+ *
+ * Author: Tom Lendacky <thomas.lendacky@amd.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/scatterlist.h>
+#include <linux/crypto.h>
+#include <crypto/algapi.h>
+#include <crypto/aes.h>
+#include <crypto/hash.h>
+#include <crypto/internal/hash.h>
+#include <crypto/scatterwalk.h>
+
+#include "ccp-crypto.h"
+
+
+static int ccp_aes_cmac_complete(struct crypto_async_request *async_req,
+				 int ret)
+{
+	struct ahash_request *req = ahash_request_cast(async_req);
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+	struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
+	unsigned int digest_size = crypto_ahash_digestsize(tfm);
+
+	if (ret)
+		goto e_free;
+
+	if (rctx->hash_rem) {
+		/* Save remaining data to buffer */
+		scatterwalk_map_and_copy(rctx->buf, rctx->cmd.u.aes.src,
+					 rctx->hash_cnt, rctx->hash_rem, 0);
+		rctx->buf_count = rctx->hash_rem;
+	} else
+		rctx->buf_count = 0;
+
+	memcpy(req->result, rctx->iv, digest_size);
+
+e_free:
+	sg_free_table(&rctx->data_sg);
+
+	return ret;
+}
+
+static int ccp_do_cmac_update(struct ahash_request *req, unsigned int nbytes,
+			      unsigned int final)
+{
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+	struct ccp_ctx *ctx = crypto_ahash_ctx(tfm);
+	struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
+	struct scatterlist *sg, *cmac_key_sg = NULL;
+	unsigned int block_size =
+		crypto_tfm_alg_blocksize(crypto_ahash_tfm(tfm));
+	unsigned int len, need_pad, sg_count;
+	int ret;
+
+	if (!ctx->u.aes.key_len) {
+		pr_err("AES key not set\n");
+		return -EINVAL;
+	}
+
+	if (nbytes)
+		rctx->null_msg = 0;
+
+	if (!final && ((nbytes + rctx->buf_count) <= block_size)) {
+		scatterwalk_map_and_copy(rctx->buf + rctx->buf_count, req->src,
+					 0, nbytes, 0);
+		rctx->buf_count += nbytes;
+
+		return 0;
+	}
+
+	len = rctx->buf_count + nbytes;
+
+	rctx->final = final;
+	rctx->hash_cnt = final ? len : len & ~(block_size - 1);
+	rctx->hash_rem = final ?   0 : len &  (block_size - 1);
+	if (!final && (rctx->hash_cnt == len)) {
+		/* CCP can't do zero length final, so keep some data around */
+		rctx->hash_cnt -= block_size;
+		rctx->hash_rem = block_size;
+	}
+
+	if (final && (rctx->null_msg || (len & (block_size - 1))))
+		need_pad = 1;
+	else
+		need_pad = 0;
+
+	sg_init_one(&rctx->iv_sg, rctx->iv, sizeof(rctx->iv));
+
+	/* Build the data scatterlist table - allocate enough entries for all
+	 * possible data pieces (buffer, input data, padding)
+	 */
+	sg_count = (nbytes) ? sg_nents(req->src) + 2 : 2;
+	ret = sg_alloc_table(&rctx->data_sg, sg_count, GFP_KERNEL);
+	if (ret)
+		return ret;
+
+	sg = NULL;
+	if (rctx->buf_count) {
+		sg_init_one(&rctx->buf_sg, rctx->buf, rctx->buf_count);
+		sg = ccp_crypto_sg_table_add(&rctx->data_sg, &rctx->buf_sg);
+	}
+
+	if (nbytes)
+		sg = ccp_crypto_sg_table_add(&rctx->data_sg, req->src);
+
+	if (need_pad) {
+		int pad_length = block_size - (len & (block_size - 1));
+
+		rctx->hash_cnt += pad_length;
+
+		memset(rctx->pad, 0, sizeof(rctx->pad));
+		rctx->pad[0] = 0x80;
+		sg_init_one(&rctx->pad_sg, rctx->pad, pad_length);
+		sg = ccp_crypto_sg_table_add(&rctx->data_sg, &rctx->pad_sg);
+	}
+	if (sg)
+		sg_mark_end(sg);
+
+	/* Initialize the K1/K2 scatterlist */
+	if (final)
+		cmac_key_sg = (need_pad) ? &ctx->u.aes.k2_sg
+					 : &ctx->u.aes.k1_sg;
+
+	memset(&rctx->cmd, 0, sizeof(rctx->cmd));
+	INIT_LIST_HEAD(&rctx->cmd.entry);
+	rctx->cmd.engine = CCP_ENGINE_AES;
+	rctx->cmd.u.aes.type = ctx->u.aes.type;
+	rctx->cmd.u.aes.mode = ctx->u.aes.mode;
+	rctx->cmd.u.aes.action = CCP_AES_ACTION_ENCRYPT;
+	rctx->cmd.u.aes.key = &ctx->u.aes.key_sg;
+	rctx->cmd.u.aes.key_len = ctx->u.aes.key_len;
+	rctx->cmd.u.aes.iv = &rctx->iv_sg;
+	rctx->cmd.u.aes.iv_len = AES_BLOCK_SIZE;
+	rctx->cmd.u.aes.src = (sg) ? rctx->data_sg.sgl : NULL;
+	rctx->cmd.u.aes.src_len = rctx->hash_cnt;
+	rctx->cmd.u.aes.dst = NULL;
+	rctx->cmd.u.aes.cmac_key = cmac_key_sg;
+	rctx->cmd.u.aes.cmac_key_len = ctx->u.aes.kn_len;
+	rctx->cmd.u.aes.cmac_final = final;
+
+	ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd);
+
+	return ret;
+}
+
+static int ccp_aes_cmac_init(struct ahash_request *req)
+{
+	struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
+
+	memset(rctx, 0, sizeof(*rctx));
+
+	rctx->null_msg = 1;
+
+	return 0;
+}
+
+static int ccp_aes_cmac_update(struct ahash_request *req)
+{
+	return ccp_do_cmac_update(req, req->nbytes, 0);
+}
+
+static int ccp_aes_cmac_final(struct ahash_request *req)
+{
+	return ccp_do_cmac_update(req, 0, 1);
+}
+
+static int ccp_aes_cmac_finup(struct ahash_request *req)
+{
+	return ccp_do_cmac_update(req, req->nbytes, 1);
+}
+
+static int ccp_aes_cmac_digest(struct ahash_request *req)
+{
+	int ret;
+
+	ret = ccp_aes_cmac_init(req);
+	if (ret)
+		return ret;
+
+	return ccp_do_cmac_update(req, req->nbytes, 1);
+}
+
+static int ccp_aes_cmac_setkey(struct crypto_ahash *tfm, const u8 *key,
+			   unsigned int key_len)
+{
+	struct ccp_ctx *ctx = crypto_tfm_ctx(crypto_ahash_tfm(tfm));
+	struct ccp_crypto_ahash_alg *alg =
+		ccp_crypto_ahash_alg(crypto_ahash_tfm(tfm));
+	u64 k0_hi, k0_lo, k1_hi, k1_lo, k2_hi, k2_lo;
+	u64 rb_hi = 0x00, rb_lo = 0x87;
+	__be64 *gk;
+	int ret;
+
+	switch (key_len) {
+	case AES_KEYSIZE_128:
+		ctx->u.aes.type = CCP_AES_TYPE_128;
+		break;
+	case AES_KEYSIZE_192:
+		ctx->u.aes.type = CCP_AES_TYPE_192;
+		break;
+	case AES_KEYSIZE_256:
+		ctx->u.aes.type = CCP_AES_TYPE_256;
+		break;
+	default:
+		crypto_ahash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
+		return -EINVAL;
+	}
+	ctx->u.aes.mode = alg->mode;
+
+	/* Set to zero until complete */
+	ctx->u.aes.key_len = 0;
+
+	/* Set the key for the AES cipher used to generate the keys */
+	ret = crypto_cipher_setkey(ctx->u.aes.tfm_cipher, key, key_len);
+	if (ret)
+		return ret;
+
+	/* Encrypt a block of zeroes - use key area in context */
+	memset(ctx->u.aes.key, 0, sizeof(ctx->u.aes.key));
+	crypto_cipher_encrypt_one(ctx->u.aes.tfm_cipher, ctx->u.aes.key,
+				  ctx->u.aes.key);
+
+	/* Generate K1 and K2 */
+	k0_hi = be64_to_cpu(*((__be64 *)ctx->u.aes.key));
+	k0_lo = be64_to_cpu(*((__be64 *)ctx->u.aes.key + 1));
+
+	k1_hi = (k0_hi << 1) | (k0_lo >> 63);
+	k1_lo = k0_lo << 1;
+	if (ctx->u.aes.key[0] & 0x80) {
+		k1_hi ^= rb_hi;
+		k1_lo ^= rb_lo;
+	}
+	gk = (__be64 *)ctx->u.aes.k1;
+	*gk = cpu_to_be64(k1_hi);
+	gk++;
+	*gk = cpu_to_be64(k1_lo);
+
+	k2_hi = (k1_hi << 1) | (k1_lo >> 63);
+	k2_lo = k1_lo << 1;
+	if (ctx->u.aes.k1[0] & 0x80) {
+		k2_hi ^= rb_hi;
+		k2_lo ^= rb_lo;
+	}
+	gk = (__be64 *)ctx->u.aes.k2;
+	*gk = cpu_to_be64(k2_hi);
+	gk++;
+	*gk = cpu_to_be64(k2_lo);
+
+	ctx->u.aes.kn_len = sizeof(ctx->u.aes.k1);
+	sg_init_one(&ctx->u.aes.k1_sg, ctx->u.aes.k1, sizeof(ctx->u.aes.k1));
+	sg_init_one(&ctx->u.aes.k2_sg, ctx->u.aes.k2, sizeof(ctx->u.aes.k2));
+
+	/* Save the supplied key */
+	memset(ctx->u.aes.key, 0, sizeof(ctx->u.aes.key));
+	memcpy(ctx->u.aes.key, key, key_len);
+	ctx->u.aes.key_len = key_len;
+	sg_init_one(&ctx->u.aes.key_sg, ctx->u.aes.key, key_len);
+
+	return ret;
+}
+
+static int ccp_aes_cmac_cra_init(struct crypto_tfm *tfm)
+{
+	struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
+	struct crypto_ahash *ahash = __crypto_ahash_cast(tfm);
+	struct crypto_cipher *cipher_tfm;
+
+	ctx->complete = ccp_aes_cmac_complete;
+	ctx->u.aes.key_len = 0;
+
+	crypto_ahash_set_reqsize(ahash, sizeof(struct ccp_aes_cmac_req_ctx));
+
+	cipher_tfm = crypto_alloc_cipher("aes", 0,
+			CRYPTO_ALG_ASYNC | CRYPTO_ALG_NEED_FALLBACK);
+	if (IS_ERR(cipher_tfm)) {
+		pr_warn("could not load aes cipher driver\n");
+		return PTR_ERR(cipher_tfm);
+	}
+	ctx->u.aes.tfm_cipher = cipher_tfm;
+
+	return 0;
+}
+
+static void ccp_aes_cmac_cra_exit(struct crypto_tfm *tfm)
+{
+	struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	if (ctx->u.aes.tfm_cipher)
+		crypto_free_cipher(ctx->u.aes.tfm_cipher);
+	ctx->u.aes.tfm_cipher = NULL;
+}
+
+int ccp_register_aes_cmac_algs(struct list_head *head)
+{
+	struct ccp_crypto_ahash_alg *ccp_alg;
+	struct ahash_alg *alg;
+	struct hash_alg_common *halg;
+	struct crypto_alg *base;
+	int ret;
+
+	ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL);
+	if (!ccp_alg)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&ccp_alg->entry);
+	ccp_alg->mode = CCP_AES_MODE_CMAC;
+
+	alg = &ccp_alg->alg;
+	alg->init = ccp_aes_cmac_init;
+	alg->update = ccp_aes_cmac_update;
+	alg->final = ccp_aes_cmac_final;
+	alg->finup = ccp_aes_cmac_finup;
+	alg->digest = ccp_aes_cmac_digest;
+	alg->setkey = ccp_aes_cmac_setkey;
+
+	halg = &alg->halg;
+	halg->digestsize = AES_BLOCK_SIZE;
+
+	base = &halg->base;
+	snprintf(base->cra_name, CRYPTO_MAX_ALG_NAME, "cmac(aes)");
+	snprintf(base->cra_driver_name, CRYPTO_MAX_ALG_NAME, "cmac-aes-ccp");
+	base->cra_flags = CRYPTO_ALG_TYPE_AHASH | CRYPTO_ALG_ASYNC |
+			  CRYPTO_ALG_KERN_DRIVER_ONLY |
+			  CRYPTO_ALG_NEED_FALLBACK;
+	base->cra_blocksize = AES_BLOCK_SIZE;
+	base->cra_ctxsize = sizeof(struct ccp_ctx);
+	base->cra_priority = CCP_CRA_PRIORITY;
+	base->cra_type = &crypto_ahash_type;
+	base->cra_init = ccp_aes_cmac_cra_init;
+	base->cra_exit = ccp_aes_cmac_cra_exit;
+	base->cra_module = THIS_MODULE;
+
+	ret = crypto_register_ahash(alg);
+	if (ret) {
+		pr_err("%s ahash algorithm registration error (%d)\n",
+			base->cra_name, ret);
+		kfree(ccp_alg);
+		return ret;
+	}
+
+	list_add(&ccp_alg->entry, head);
+
+	return 0;
+}