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

   1 /*
   2  * AMD Cryptographic Coprocessor (CCP) AES XTS crypto API support
   3  *
   4  * Copyright (C) 2013 Advanced Micro Devices, Inc.
   5  *
   6  * Author: Tom Lendacky <thomas.lendacky@amd.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/sched.h>
  15 #include <linux/delay.h>
  16 #include <linux/scatterlist.h>
  17 #include <linux/crypto.h>
  18 #include <crypto/algapi.h>
  19 #include <crypto/aes.h>
  20 #include <crypto/scatterwalk.h>
  21
  22 #include "ccp-crypto.h"
  23
  24 struct ccp_aes_xts_def {
  25         const char *name;
  26         const char *drv_name;
  27 };
  28
  29 static struct ccp_aes_xts_def aes_xts_algs[] = {
  30         {
  31                 .name           = "xts(aes)",
  32                 .drv_name       = "xts-aes-ccp",
  33         },
  34 };
  35
  36 struct ccp_unit_size_map {
  37         unsigned int size;
  38         u32 value;
  39 };
  40
  41 static struct ccp_unit_size_map unit_size_map[] = {
  42         {
  43                 .size   = 4096,
  44                 .value  = CCP_XTS_AES_UNIT_SIZE_4096,
  45         },
  46         {
  47                 .size   = 2048,
  48                 .value  = CCP_XTS_AES_UNIT_SIZE_2048,
  49         },
  50         {
  51                 .size   = 1024,
  52                 .value  = CCP_XTS_AES_UNIT_SIZE_1024,
  53         },
  54         {
  55                 .size   = 512,
  56                 .value  = CCP_XTS_AES_UNIT_SIZE_512,
  57         },
  58         {
  59                 .size   = 256,
  60                 .value  = CCP_XTS_AES_UNIT_SIZE__LAST,
  61         },
  62         {
  63                 .size   = 128,
  64                 .value  = CCP_XTS_AES_UNIT_SIZE__LAST,
  65         },
  66         {
  67                 .size   = 64,
  68                 .value  = CCP_XTS_AES_UNIT_SIZE__LAST,
  69         },
  70         {
  71                 .size   = 32,
  72                 .value  = CCP_XTS_AES_UNIT_SIZE__LAST,
  73         },
  74         {
  75                 .size   = 16,
  76                 .value  = CCP_XTS_AES_UNIT_SIZE_16,
  77         },
  78         {
  79                 .size   = 1,
  80                 .value  = CCP_XTS_AES_UNIT_SIZE__LAST,
  81         },
  82 };
  83
  84 static int ccp_aes_xts_complete(struct crypto_async_request *async_req, int ret)
  85 {
  86         struct ablkcipher_request *req = ablkcipher_request_cast(async_req);
  87         struct ccp_aes_req_ctx *rctx = ablkcipher_request_ctx(req);
  88
  89         if (ret)
  90                 return ret;
  91
  92         memcpy(req->info, rctx->iv, AES_BLOCK_SIZE);
  93
  94         return 0;
  95 }
  96
  97 static int ccp_aes_xts_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
  98                               unsigned int key_len)
  99 {
 100         struct ccp_ctx *ctx = crypto_tfm_ctx(crypto_ablkcipher_tfm(tfm));
 101
 102         /* Only support 128-bit AES key with a 128-bit Tweak key,
 103          * otherwise use the fallback
 104          */
 105         switch (key_len) {
 106         case AES_KEYSIZE_128 * 2:
 107                 memcpy(ctx->u.aes.key, key, key_len);
 108                 break;
 109         }
 110         ctx->u.aes.key_len = key_len / 2;
 111         sg_init_one(&ctx->u.aes.key_sg, ctx->u.aes.key, key_len);
 112
 113         return crypto_ablkcipher_setkey(ctx->u.aes.tfm_ablkcipher, key,
 114                                         key_len);
 115 }
 116
 117 static int ccp_aes_xts_crypt(struct ablkcipher_request *req,
 118                              unsigned int encrypt)
 119 {
 120         struct crypto_tfm *tfm =
 121                 crypto_ablkcipher_tfm(crypto_ablkcipher_reqtfm(req));
 122         struct ccp_ctx *ctx = crypto_tfm_ctx(req->base.tfm);
 123         struct ccp_aes_req_ctx *rctx = ablkcipher_request_ctx(req);
 124         unsigned int unit;
 125         int ret;
 126
 127         if (!ctx->u.aes.key_len)
 128                 return -EINVAL;
 129
 130         if (req->nbytes & (AES_BLOCK_SIZE - 1))
 131                 return -EINVAL;
 132
 133         if (!req->info)
 134                 return -EINVAL;
 135
 136         for (unit = 0; unit < ARRAY_SIZE(unit_size_map); unit++)
 137                 if (!(req->nbytes & (unit_size_map[unit].size - 1)))
 138                         break;
 139
 140         if ((unit_size_map[unit].value == CCP_XTS_AES_UNIT_SIZE__LAST) ||
 141             (ctx->u.aes.key_len != AES_KEYSIZE_128)) {
 142                 /* Use the fallback to process the request for any
 143                  * unsupported unit sizes or key sizes
 144                  */
 145                 ablkcipher_request_set_tfm(req, ctx->u.aes.tfm_ablkcipher);
 146                 ret = (encrypt) ? crypto_ablkcipher_encrypt(req) :
 147                                   crypto_ablkcipher_decrypt(req);
 148                 ablkcipher_request_set_tfm(req, __crypto_ablkcipher_cast(tfm));
 149
 150                 return ret;
 151         }
 152
 153         memcpy(rctx->iv, req->info, AES_BLOCK_SIZE);
 154         sg_init_one(&rctx->iv_sg, rctx->iv, AES_BLOCK_SIZE);
 155
 156         memset(&rctx->cmd, 0, sizeof(rctx->cmd));
 157         INIT_LIST_HEAD(&rctx->cmd.entry);
 158         rctx->cmd.engine = CCP_ENGINE_XTS_AES_128;
 159         rctx->cmd.u.xts.action = (encrypt) ? CCP_AES_ACTION_ENCRYPT
 160                                            : CCP_AES_ACTION_DECRYPT;
 161         rctx->cmd.u.xts.unit_size = unit_size_map[unit].value;
 162         rctx->cmd.u.xts.key = &ctx->u.aes.key_sg;
 163         rctx->cmd.u.xts.key_len = ctx->u.aes.key_len;
 164         rctx->cmd.u.xts.iv = &rctx->iv_sg;
 165         rctx->cmd.u.xts.iv_len = AES_BLOCK_SIZE;
 166         rctx->cmd.u.xts.src = req->src;
 167         rctx->cmd.u.xts.src_len = req->nbytes;
 168         rctx->cmd.u.xts.dst = req->dst;
 169
 170         ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd);
 171
 172         return ret;
 173 }
 174
 175 static int ccp_aes_xts_encrypt(struct ablkcipher_request *req)
 176 {
 177         return ccp_aes_xts_crypt(req, 1);
 178 }
 179
 180 static int ccp_aes_xts_decrypt(struct ablkcipher_request *req)
 181 {
 182         return ccp_aes_xts_crypt(req, 0);
 183 }
 184
 185 static int ccp_aes_xts_cra_init(struct crypto_tfm *tfm)
 186 {
 187         struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
 188         struct crypto_ablkcipher *fallback_tfm;
 189
 190         ctx->complete = ccp_aes_xts_complete;
 191         ctx->u.aes.key_len = 0;
 192
 193         fallback_tfm = crypto_alloc_ablkcipher(crypto_tfm_alg_name(tfm), 0,
 194                                                CRYPTO_ALG_ASYNC |
 195                                                CRYPTO_ALG_NEED_FALLBACK);
 196         if (IS_ERR(fallback_tfm)) {
 197                 pr_warn("could not load fallback driver %s\n",
 198                         crypto_tfm_alg_name(tfm));
 199                 return PTR_ERR(fallback_tfm);
 200         }
 201         ctx->u.aes.tfm_ablkcipher = fallback_tfm;
 202
 203         tfm->crt_ablkcipher.reqsize = sizeof(struct ccp_aes_req_ctx) +
 204                                       fallback_tfm->base.crt_ablkcipher.reqsize;
 205
 206         return 0;
 207 }
 208
 209 static void ccp_aes_xts_cra_exit(struct crypto_tfm *tfm)
 210 {
 211         struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
 212
 213         if (ctx->u.aes.tfm_ablkcipher)
 214                 crypto_free_ablkcipher(ctx->u.aes.tfm_ablkcipher);
 215         ctx->u.aes.tfm_ablkcipher = NULL;
 216 }
 217
 218 static int ccp_register_aes_xts_alg(struct list_head *head,
 219                                     const struct ccp_aes_xts_def *def)
 220 {
 221         struct ccp_crypto_ablkcipher_alg *ccp_alg;
 222         struct crypto_alg *alg;
 223         int ret;
 224
 225         ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL);
 226         if (!ccp_alg)
 227                 return -ENOMEM;
 228
 229         INIT_LIST_HEAD(&ccp_alg->entry);
 230
 231         alg = &ccp_alg->alg;
 232
 233         snprintf(alg->cra_name, CRYPTO_MAX_ALG_NAME, "%s", def->name);
 234         snprintf(alg->cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s",
 235                  def->drv_name);
 236         alg->cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC |
 237                          CRYPTO_ALG_KERN_DRIVER_ONLY |
 238                          CRYPTO_ALG_NEED_FALLBACK;
 239         alg->cra_blocksize = AES_BLOCK_SIZE;
 240         alg->cra_ctxsize = sizeof(struct ccp_ctx);
 241         alg->cra_priority = CCP_CRA_PRIORITY;
 242         alg->cra_type = &crypto_ablkcipher_type;
 243         alg->cra_ablkcipher.setkey = ccp_aes_xts_setkey;
 244         alg->cra_ablkcipher.encrypt = ccp_aes_xts_encrypt;
 245         alg->cra_ablkcipher.decrypt = ccp_aes_xts_decrypt;
 246         alg->cra_ablkcipher.min_keysize = AES_MIN_KEY_SIZE * 2;
 247         alg->cra_ablkcipher.max_keysize = AES_MAX_KEY_SIZE * 2;
 248         alg->cra_ablkcipher.ivsize = AES_BLOCK_SIZE;
 249         alg->cra_init = ccp_aes_xts_cra_init;
 250         alg->cra_exit = ccp_aes_xts_cra_exit;
 251         alg->cra_module = THIS_MODULE;
 252
 253         ret = crypto_register_alg(alg);
 254         if (ret) {
 255                 pr_err("%s ablkcipher algorithm registration error (%d)\n",
 256                        alg->cra_name, ret);
 257                 kfree(ccp_alg);
 258                 return ret;
 259         }
 260
 261         list_add(&ccp_alg->entry, head);
 262
 263         return 0;
 264 }
 265
 266 int ccp_register_aes_xts_algs(struct list_head *head)
 267 {
 268         int i, ret;
 269
 270         for (i = 0; i < ARRAY_SIZE(aes_xts_algs); i++) {
 271                 ret = ccp_register_aes_xts_alg(head, &aes_xts_algs[i]);
 272                 if (ret)
 273                         return ret;
 274         }
 275
 276         return 0;
 277 }