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 <crypto/aes.h>
  18 #include <crypto/internal/skcipher.h>
  19 #include <crypto/scatterwalk.h>
  20
  21 #include "ccp-crypto.h"
  22
  23 struct ccp_aes_xts_def {
  24         const char *name;
  25         const char *drv_name;
  26 };
  27
  28 static struct ccp_aes_xts_def aes_xts_algs[] = {
  29         {
  30                 .name           = "xts(aes)",
  31                 .drv_name       = "xts-aes-ccp",
  32         },
  33 };
  34
  35 struct ccp_unit_size_map {
  36         unsigned int size;
  37         u32 value;
  38 };
  39
  40 static struct ccp_unit_size_map unit_size_map[] = {
  41         {
  42                 .size   = 4096,
  43                 .value  = CCP_XTS_AES_UNIT_SIZE_4096,
  44         },
  45         {
  46                 .size   = 2048,
  47                 .value  = CCP_XTS_AES_UNIT_SIZE_2048,
  48         },
  49         {
  50                 .size   = 1024,
  51                 .value  = CCP_XTS_AES_UNIT_SIZE_1024,
  52         },
  53         {
  54                 .size   = 512,
  55                 .value  = CCP_XTS_AES_UNIT_SIZE_512,
  56         },
  57         {
  58                 .size   = 256,
  59                 .value  = CCP_XTS_AES_UNIT_SIZE__LAST,
  60         },
  61         {
  62                 .size   = 128,
  63                 .value  = CCP_XTS_AES_UNIT_SIZE__LAST,
  64         },
  65         {
  66                 .size   = 64,
  67                 .value  = CCP_XTS_AES_UNIT_SIZE__LAST,
  68         },
  69         {
  70                 .size   = 32,
  71                 .value  = CCP_XTS_AES_UNIT_SIZE__LAST,
  72         },
  73         {
  74                 .size   = 16,
  75                 .value  = CCP_XTS_AES_UNIT_SIZE_16,
  76         },
  77         {
  78                 .size   = 1,
  79                 .value  = CCP_XTS_AES_UNIT_SIZE__LAST,
  80         },
  81 };
  82
  83 static int ccp_aes_xts_complete(struct crypto_async_request *async_req, int ret)
  84 {
  85         struct ablkcipher_request *req = ablkcipher_request_cast(async_req);
  86         struct ccp_aes_req_ctx *rctx = ablkcipher_request_ctx(req);
  87
  88         if (ret)
  89                 return ret;
  90
  91         memcpy(req->info, rctx->iv, AES_BLOCK_SIZE);
  92
  93         return 0;
  94 }
  95
  96 static int ccp_aes_xts_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
  97                               unsigned int key_len)
  98 {
  99         struct ccp_ctx *ctx = crypto_tfm_ctx(crypto_ablkcipher_tfm(tfm));
 100
 101         /* Only support 128-bit AES key with a 128-bit Tweak key,
 102          * otherwise use the fallback
 103          */
 104         switch (key_len) {
 105         case AES_KEYSIZE_128 * 2:
 106                 memcpy(ctx->u.aes.key, key, key_len);
 107                 break;
 108         }
 109         ctx->u.aes.key_len = key_len / 2;
 110         sg_init_one(&ctx->u.aes.key_sg, ctx->u.aes.key, key_len);
 111
 112         return crypto_skcipher_setkey(ctx->u.aes.tfm_skcipher, key, key_len);
 113 }
 114
 115 static int ccp_aes_xts_crypt(struct ablkcipher_request *req,
 116                              unsigned int encrypt)
 117 {
 118         struct ccp_ctx *ctx = crypto_tfm_ctx(req->base.tfm);
 119         struct ccp_aes_req_ctx *rctx = ablkcipher_request_ctx(req);
 120         unsigned int unit;
 121         u32 unit_size;
 122         int ret;
 123
 124         if (!ctx->u.aes.key_len)
 125                 return -EINVAL;
 126
 127         if (req->nbytes & (AES_BLOCK_SIZE - 1))
 128                 return -EINVAL;
 129
 130         if (!req->info)
 131                 return -EINVAL;
 132
 133         unit_size = CCP_XTS_AES_UNIT_SIZE__LAST;
 134         if (req->nbytes <= unit_size_map[0].size) {
 135                 for (unit = 0; unit < ARRAY_SIZE(unit_size_map); unit++) {
 136                         if (!(req->nbytes & (unit_size_map[unit].size - 1))) {
 137                                 unit_size = unit_size_map[unit].value;
 138                                 break;
 139                         }
 140                 }
 141         }
 142
 143         if ((unit_size == CCP_XTS_AES_UNIT_SIZE__LAST) ||
 144             (ctx->u.aes.key_len != AES_KEYSIZE_128)) {
 145                 SKCIPHER_REQUEST_ON_STACK(subreq, ctx->u.aes.tfm_skcipher);
 146
 147                 /* Use the fallback to process the request for any
 148                  * unsupported unit sizes or key sizes
 149                  */
 150                 skcipher_request_set_tfm(subreq, ctx->u.aes.tfm_skcipher);
 151                 skcipher_request_set_callback(subreq, req->base.flags,
 152                                               NULL, NULL);
 153                 skcipher_request_set_crypt(subreq, req->src, req->dst,
 154                                            req->nbytes, req->info);
 155                 ret = encrypt ? crypto_skcipher_encrypt(subreq) :
 156                                 crypto_skcipher_decrypt(subreq);
 157                 skcipher_request_zero(subreq);
 158                 return ret;
 159         }
 160
 161         memcpy(rctx->iv, req->info, AES_BLOCK_SIZE);
 162         sg_init_one(&rctx->iv_sg, rctx->iv, AES_BLOCK_SIZE);
 163
 164         memset(&rctx->cmd, 0, sizeof(rctx->cmd));
 165         INIT_LIST_HEAD(&rctx->cmd.entry);
 166         rctx->cmd.engine = CCP_ENGINE_XTS_AES_128;
 167         rctx->cmd.u.xts.action = (encrypt) ? CCP_AES_ACTION_ENCRYPT
 168                                            : CCP_AES_ACTION_DECRYPT;
 169         rctx->cmd.u.xts.unit_size = unit_size;
 170         rctx->cmd.u.xts.key = &ctx->u.aes.key_sg;
 171         rctx->cmd.u.xts.key_len = ctx->u.aes.key_len;
 172         rctx->cmd.u.xts.iv = &rctx->iv_sg;
 173         rctx->cmd.u.xts.iv_len = AES_BLOCK_SIZE;
 174         rctx->cmd.u.xts.src = req->src;
 175         rctx->cmd.u.xts.src_len = req->nbytes;
 176         rctx->cmd.u.xts.dst = req->dst;
 177
 178         ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd);
 179
 180         return ret;
 181 }
 182
 183 static int ccp_aes_xts_encrypt(struct ablkcipher_request *req)
 184 {
 185         return ccp_aes_xts_crypt(req, 1);
 186 }
 187
 188 static int ccp_aes_xts_decrypt(struct ablkcipher_request *req)
 189 {
 190         return ccp_aes_xts_crypt(req, 0);
 191 }
 192
 193 static int ccp_aes_xts_cra_init(struct crypto_tfm *tfm)
 194 {
 195         struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
 196         struct crypto_skcipher *fallback_tfm;
 197
 198         ctx->complete = ccp_aes_xts_complete;
 199         ctx->u.aes.key_len = 0;
 200
 201         fallback_tfm = crypto_alloc_skcipher("xts(aes)", 0,
 202                                              CRYPTO_ALG_ASYNC |
 203                                              CRYPTO_ALG_NEED_FALLBACK);
 204         if (IS_ERR(fallback_tfm)) {
 205                 pr_warn("could not load fallback driver xts(aes)\n");
 206                 return PTR_ERR(fallback_tfm);
 207         }
 208         ctx->u.aes.tfm_skcipher = fallback_tfm;
 209
 210         tfm->crt_ablkcipher.reqsize = sizeof(struct ccp_aes_req_ctx);
 211
 212         return 0;
 213 }
 214
 215 static void ccp_aes_xts_cra_exit(struct crypto_tfm *tfm)
 216 {
 217         struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
 218
 219         crypto_free_skcipher(ctx->u.aes.tfm_skcipher);
 220 }
 221
 222 static int ccp_register_aes_xts_alg(struct list_head *head,
 223                                     const struct ccp_aes_xts_def *def)
 224 {
 225         struct ccp_crypto_ablkcipher_alg *ccp_alg;
 226         struct crypto_alg *alg;
 227         int ret;
 228
 229         ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL);
 230         if (!ccp_alg)
 231                 return -ENOMEM;
 232
 233         INIT_LIST_HEAD(&ccp_alg->entry);
 234
 235         alg = &ccp_alg->alg;
 236
 237         snprintf(alg->cra_name, CRYPTO_MAX_ALG_NAME, "%s", def->name);
 238         snprintf(alg->cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s",
 239                  def->drv_name);
 240         alg->cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC |
 241                          CRYPTO_ALG_KERN_DRIVER_ONLY |
 242                          CRYPTO_ALG_NEED_FALLBACK;
 243         alg->cra_blocksize = AES_BLOCK_SIZE;
 244         alg->cra_ctxsize = sizeof(struct ccp_ctx);
 245         alg->cra_priority = CCP_CRA_PRIORITY;
 246         alg->cra_type = &crypto_ablkcipher_type;
 247         alg->cra_ablkcipher.setkey = ccp_aes_xts_setkey;
 248         alg->cra_ablkcipher.encrypt = ccp_aes_xts_encrypt;
 249         alg->cra_ablkcipher.decrypt = ccp_aes_xts_decrypt;
 250         alg->cra_ablkcipher.min_keysize = AES_MIN_KEY_SIZE * 2;
 251         alg->cra_ablkcipher.max_keysize = AES_MAX_KEY_SIZE * 2;
 252         alg->cra_ablkcipher.ivsize = AES_BLOCK_SIZE;
 253         alg->cra_init = ccp_aes_xts_cra_init;
 254         alg->cra_exit = ccp_aes_xts_cra_exit;
 255         alg->cra_module = THIS_MODULE;
 256
 257         ret = crypto_register_alg(alg);
 258         if (ret) {
 259                 pr_err("%s ablkcipher algorithm registration error (%d)\n",
 260                        alg->cra_name, ret);
 261                 kfree(ccp_alg);
 262                 return ret;
 263         }
 264
 265         list_add(&ccp_alg->entry, head);
 266
 267         return 0;
 268 }
 269
 270 int ccp_register_aes_xts_algs(struct list_head *head)
 271 {
 272         int i, ret;
 273
 274         for (i = 0; i < ARRAY_SIZE(aes_xts_algs); i++) {
 275                 ret = ccp_register_aes_xts_alg(head, &aes_xts_algs[i]);
 276                 if (ret)
 277                         return ret;
 278         }
 279
 280         return 0;
 281 }