blob: 58a4244b4752997fdc645304db0f1f881451e67f [file] [log] [blame]
/*
* AMD Cryptographic Coprocessor (CCP) AES XTS 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 <crypto/aes.h>
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
#include "ccp-crypto.h"
struct ccp_aes_xts_def {
const char *name;
const char *drv_name;
};
static struct ccp_aes_xts_def aes_xts_algs[] = {
{
.name = "xts(aes)",
.drv_name = "xts-aes-ccp",
},
};
struct ccp_unit_size_map {
unsigned int size;
u32 value;
};
static struct ccp_unit_size_map unit_size_map[] = {
{
.size = 4096,
.value = CCP_XTS_AES_UNIT_SIZE_4096,
},
{
.size = 2048,
.value = CCP_XTS_AES_UNIT_SIZE_2048,
},
{
.size = 1024,
.value = CCP_XTS_AES_UNIT_SIZE_1024,
},
{
.size = 512,
.value = CCP_XTS_AES_UNIT_SIZE_512,
},
{
.size = 256,
.value = CCP_XTS_AES_UNIT_SIZE__LAST,
},
{
.size = 128,
.value = CCP_XTS_AES_UNIT_SIZE__LAST,
},
{
.size = 64,
.value = CCP_XTS_AES_UNIT_SIZE__LAST,
},
{
.size = 32,
.value = CCP_XTS_AES_UNIT_SIZE__LAST,
},
{
.size = 16,
.value = CCP_XTS_AES_UNIT_SIZE_16,
},
{
.size = 1,
.value = CCP_XTS_AES_UNIT_SIZE__LAST,
},
};
static int ccp_aes_xts_complete(struct crypto_async_request *async_req, int ret)
{
struct ablkcipher_request *req = ablkcipher_request_cast(async_req);
struct ccp_aes_req_ctx *rctx = ablkcipher_request_ctx(req);
if (ret)
return ret;
memcpy(req->info, rctx->iv, AES_BLOCK_SIZE);
return 0;
}
static int ccp_aes_xts_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
unsigned int key_len)
{
struct ccp_ctx *ctx = crypto_tfm_ctx(crypto_ablkcipher_tfm(tfm));
/* Only support 128-bit AES key with a 128-bit Tweak key,
* otherwise use the fallback
*/
switch (key_len) {
case AES_KEYSIZE_128 * 2:
memcpy(ctx->u.aes.key, key, key_len);
break;
}
ctx->u.aes.key_len = key_len / 2;
sg_init_one(&ctx->u.aes.key_sg, ctx->u.aes.key, key_len);
return crypto_skcipher_setkey(ctx->u.aes.tfm_skcipher, key, key_len);
}
static int ccp_aes_xts_crypt(struct ablkcipher_request *req,
unsigned int encrypt)
{
struct ccp_ctx *ctx = crypto_tfm_ctx(req->base.tfm);
struct ccp_aes_req_ctx *rctx = ablkcipher_request_ctx(req);
unsigned int unit;
u32 unit_size;
int ret;
if (!ctx->u.aes.key_len)
return -EINVAL;
if (req->nbytes & (AES_BLOCK_SIZE - 1))
return -EINVAL;
if (!req->info)
return -EINVAL;
unit_size = CCP_XTS_AES_UNIT_SIZE__LAST;
if (req->nbytes <= unit_size_map[0].size) {
for (unit = 0; unit < ARRAY_SIZE(unit_size_map); unit++) {
if (!(req->nbytes & (unit_size_map[unit].size - 1))) {
unit_size = unit_size_map[unit].value;
break;
}
}
}
if ((unit_size == CCP_XTS_AES_UNIT_SIZE__LAST) ||
(ctx->u.aes.key_len != AES_KEYSIZE_128)) {
SKCIPHER_REQUEST_ON_STACK(subreq, ctx->u.aes.tfm_skcipher);
/* Use the fallback to process the request for any
* unsupported unit sizes or key sizes
*/
skcipher_request_set_tfm(subreq, ctx->u.aes.tfm_skcipher);
skcipher_request_set_callback(subreq, req->base.flags,
NULL, NULL);
skcipher_request_set_crypt(subreq, req->src, req->dst,
req->nbytes, req->info);
ret = encrypt ? crypto_skcipher_encrypt(subreq) :
crypto_skcipher_decrypt(subreq);
skcipher_request_zero(subreq);
return ret;
}
memcpy(rctx->iv, req->info, AES_BLOCK_SIZE);
sg_init_one(&rctx->iv_sg, rctx->iv, AES_BLOCK_SIZE);
memset(&rctx->cmd, 0, sizeof(rctx->cmd));
INIT_LIST_HEAD(&rctx->cmd.entry);
rctx->cmd.engine = CCP_ENGINE_XTS_AES_128;
rctx->cmd.u.xts.action = (encrypt) ? CCP_AES_ACTION_ENCRYPT
: CCP_AES_ACTION_DECRYPT;
rctx->cmd.u.xts.unit_size = unit_size;
rctx->cmd.u.xts.key = &ctx->u.aes.key_sg;
rctx->cmd.u.xts.key_len = ctx->u.aes.key_len;
rctx->cmd.u.xts.iv = &rctx->iv_sg;
rctx->cmd.u.xts.iv_len = AES_BLOCK_SIZE;
rctx->cmd.u.xts.src = req->src;
rctx->cmd.u.xts.src_len = req->nbytes;
rctx->cmd.u.xts.dst = req->dst;
ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd);
return ret;
}
static int ccp_aes_xts_encrypt(struct ablkcipher_request *req)
{
return ccp_aes_xts_crypt(req, 1);
}
static int ccp_aes_xts_decrypt(struct ablkcipher_request *req)
{
return ccp_aes_xts_crypt(req, 0);
}
static int ccp_aes_xts_cra_init(struct crypto_tfm *tfm)
{
struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
struct crypto_skcipher *fallback_tfm;
ctx->complete = ccp_aes_xts_complete;
ctx->u.aes.key_len = 0;
fallback_tfm = crypto_alloc_skcipher("xts(aes)", 0,
CRYPTO_ALG_ASYNC |
CRYPTO_ALG_NEED_FALLBACK);
if (IS_ERR(fallback_tfm)) {
pr_warn("could not load fallback driver xts(aes)\n");
return PTR_ERR(fallback_tfm);
}
ctx->u.aes.tfm_skcipher = fallback_tfm;
tfm->crt_ablkcipher.reqsize = sizeof(struct ccp_aes_req_ctx);
return 0;
}
static void ccp_aes_xts_cra_exit(struct crypto_tfm *tfm)
{
struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
crypto_free_skcipher(ctx->u.aes.tfm_skcipher);
}
static int ccp_register_aes_xts_alg(struct list_head *head,
const struct ccp_aes_xts_def *def)
{
struct ccp_crypto_ablkcipher_alg *ccp_alg;
struct crypto_alg *alg;
int ret;
ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL);
if (!ccp_alg)
return -ENOMEM;
INIT_LIST_HEAD(&ccp_alg->entry);
alg = &ccp_alg->alg;
snprintf(alg->cra_name, CRYPTO_MAX_ALG_NAME, "%s", def->name);
snprintf(alg->cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s",
def->drv_name);
alg->cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC |
CRYPTO_ALG_KERN_DRIVER_ONLY |
CRYPTO_ALG_NEED_FALLBACK;
alg->cra_blocksize = AES_BLOCK_SIZE;
alg->cra_ctxsize = sizeof(struct ccp_ctx);
alg->cra_priority = CCP_CRA_PRIORITY;
alg->cra_type = &crypto_ablkcipher_type;
alg->cra_ablkcipher.setkey = ccp_aes_xts_setkey;
alg->cra_ablkcipher.encrypt = ccp_aes_xts_encrypt;
alg->cra_ablkcipher.decrypt = ccp_aes_xts_decrypt;
alg->cra_ablkcipher.min_keysize = AES_MIN_KEY_SIZE * 2;
alg->cra_ablkcipher.max_keysize = AES_MAX_KEY_SIZE * 2;
alg->cra_ablkcipher.ivsize = AES_BLOCK_SIZE;
alg->cra_init = ccp_aes_xts_cra_init;
alg->cra_exit = ccp_aes_xts_cra_exit;
alg->cra_module = THIS_MODULE;
ret = crypto_register_alg(alg);
if (ret) {
pr_err("%s ablkcipher algorithm registration error (%d)\n",
alg->cra_name, ret);
kfree(ccp_alg);
return ret;
}
list_add(&ccp_alg->entry, head);
return 0;
}
int ccp_register_aes_xts_algs(struct list_head *head)
{
int i, ret;
for (i = 0; i < ARRAY_SIZE(aes_xts_algs); i++) {
ret = ccp_register_aes_xts_alg(head, &aes_xts_algs[i]);
if (ret)
return ret;
}
return 0;
}