crypto: ccp - CCP AES CMAC mode crypto API support

/*

 * 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;

}