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

   1 /*
   2  * AMD Cryptographic Coprocessor (CCP) AES XTS crypto API support
   3  *
   4  * Copyright (C) 2013,2017 Advanced Micro Devices, Inc.
   5  *
   6  * Author: Gary R Hook <gary.hook@amd.com>
   7  * Author: Tom Lendacky <thomas.lendacky@amd.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/sched.h>
  16 #include <linux/delay.h>
  17 #include <linux/scatterlist.h>
  18 #include <crypto/aes.h>
  19 #include <crypto/xts.h>
  20 #include <crypto/internal/skcipher.h>
  21 #include <crypto/scatterwalk.h>
  22
  23 #include "ccp-crypto.h"
  24
  25 struct ccp_aes_xts_def {
  26         const char *name;
  27         const char *drv_name;
  28 };
  29
  30 static struct ccp_aes_xts_def aes_xts_algs[] = {
  31         {
  32                 .name           = "xts(aes)",
  33                 .drv_name       = "xts-aes-ccp",
  34         },
  35 };
  36
  37 struct ccp_unit_size_map {
  38         unsigned int size;
  39         u32 value;
  40 };
  41
  42 static struct ccp_unit_size_map xts_unit_sizes[] = {
  43         {
  44                 .size   = 16,
  45                 .value  = CCP_XTS_AES_UNIT_SIZE_16,
  46         },
  47         {
  48                 .size   = 512,
  49                 .value  = CCP_XTS_AES_UNIT_SIZE_512,
  50         },
  51         {
  52                 .size   = 1024,
  53                 .value  = CCP_XTS_AES_UNIT_SIZE_1024,
  54         },
  55         {
  56                 .size   = 2048,
  57                 .value  = CCP_XTS_AES_UNIT_SIZE_2048,
  58         },
  59         {
  60                 .size   = 4096,
  61                 .value  = CCP_XTS_AES_UNIT_SIZE_4096,
  62         },
  63 };
  64
  65 static int ccp_aes_xts_complete(struct crypto_async_request *async_req, int ret)
  66 {
  67         struct ablkcipher_request *req = ablkcipher_request_cast(async_req);
  68         struct ccp_aes_req_ctx *rctx = ablkcipher_request_ctx(req);
  69
  70         if (ret)
  71                 return ret;
  72
  73         memcpy(req->info, rctx->iv, AES_BLOCK_SIZE);
  74
  75         return 0;
  76 }
  77
  78 static int ccp_aes_xts_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
  79                               unsigned int key_len)
  80 {
  81         struct crypto_tfm *xfm = crypto_ablkcipher_tfm(tfm);
  82         struct ccp_ctx *ctx = crypto_tfm_ctx(xfm);
  83         unsigned int ccpversion = ccp_version();
  84         int ret;
  85
  86         ret = xts_check_key(xfm, key, key_len);
  87         if (ret)
  88                 return ret;
  89
  90         /* Version 3 devices support 128-bit keys; version 5 devices can
  91          * accommodate 128- and 256-bit keys.
  92          */
  93         switch (key_len) {
  94         case AES_KEYSIZE_128 * 2:
  95                 memcpy(ctx->u.aes.key, key, key_len);
  96                 break;
  97         case AES_KEYSIZE_256 * 2:
  98                 if (ccpversion > CCP_VERSION(3, 0))
  99                         memcpy(ctx->u.aes.key, key, key_len);
 100                 break;
 101         }
 102         ctx->u.aes.key_len = key_len / 2;
 103         sg_init_one(&ctx->u.aes.key_sg, ctx->u.aes.key, key_len);
 104
 105         return crypto_sync_skcipher_setkey(ctx->u.aes.tfm_skcipher, key, key_len);
 106 }
 107
 108 static int ccp_aes_xts_crypt(struct ablkcipher_request *req,
 109                              unsigned int encrypt)
 110 {
 111         struct ccp_ctx *ctx = crypto_tfm_ctx(req->base.tfm);
 112         struct ccp_aes_req_ctx *rctx = ablkcipher_request_ctx(req);
 113         unsigned int ccpversion = ccp_version();
 114         unsigned int fallback = 0;
 115         unsigned int unit;
 116         u32 unit_size;
 117         int ret;
 118
 119         if (!ctx->u.aes.key_len)
 120                 return -EINVAL;
 121
 122         if (req->nbytes & (AES_BLOCK_SIZE - 1))
 123                 return -EINVAL;
 124
 125         if (!req->info)
 126                 return -EINVAL;
 127
 128         /* Check conditions under which the CCP can fulfill a request. The
 129          * device can handle input plaintext of a length that is a multiple
 130          * of the unit_size, bug the crypto implementation only supports
 131          * the unit_size being equal to the input length. This limits the
 132          * number of scenarios we can handle.
 133          */
 134         unit_size = CCP_XTS_AES_UNIT_SIZE__LAST;
 135         for (unit = 0; unit < ARRAY_SIZE(xts_unit_sizes); unit++) {
 136                 if (req->nbytes == xts_unit_sizes[unit].size) {
 137                         unit_size = unit;
 138                         break;
 139                 }
 140         }
 141         /* The CCP has restrictions on block sizes. Also, a version 3 device
 142          * only supports AES-128 operations; version 5 CCPs support both
 143          * AES-128 and -256 operations.
 144          */
 145         if (unit_size == CCP_XTS_AES_UNIT_SIZE__LAST)
 146                 fallback = 1;
 147         if ((ccpversion < CCP_VERSION(5, 0)) &&
 148             (ctx->u.aes.key_len != AES_KEYSIZE_128))
 149                 fallback = 1;
 150         if ((ctx->u.aes.key_len != AES_KEYSIZE_128) &&
 151             (ctx->u.aes.key_len != AES_KEYSIZE_256))
 152                 fallback = 1;
 153         if (fallback) {
 154                 SYNC_SKCIPHER_REQUEST_ON_STACK(subreq,
 155                                                ctx->u.aes.tfm_skcipher);
 156
 157                 /* Use the fallback to process the request for any
 158                  * unsupported unit sizes or key sizes
 159                  */
 160                 skcipher_request_set_sync_tfm(subreq, ctx->u.aes.tfm_skcipher);
 161                 skcipher_request_set_callback(subreq, req->base.flags,
 162                                               NULL, NULL);
 163                 skcipher_request_set_crypt(subreq, req->src, req->dst,
 164                                            req->nbytes, req->info);
 165                 ret = encrypt ? crypto_skcipher_encrypt(subreq) :
 166                                 crypto_skcipher_decrypt(subreq);
 167                 skcipher_request_zero(subreq);
 168                 return ret;
 169         }
 170
 171         memcpy(rctx->iv, req->info, AES_BLOCK_SIZE);
 172         sg_init_one(&rctx->iv_sg, rctx->iv, AES_BLOCK_SIZE);
 173
 174         memset(&rctx->cmd, 0, sizeof(rctx->cmd));
 175         INIT_LIST_HEAD(&rctx->cmd.entry);
 176         rctx->cmd.engine = CCP_ENGINE_XTS_AES_128;
 177         rctx->cmd.u.xts.type = CCP_AES_TYPE_128;
 178         rctx->cmd.u.xts.action = (encrypt) ? CCP_AES_ACTION_ENCRYPT
 179                                            : CCP_AES_ACTION_DECRYPT;
 180         rctx->cmd.u.xts.unit_size = unit_size;
 181         rctx->cmd.u.xts.key = &ctx->u.aes.key_sg;
 182         rctx->cmd.u.xts.key_len = ctx->u.aes.key_len;
 183         rctx->cmd.u.xts.iv = &rctx->iv_sg;
 184         rctx->cmd.u.xts.iv_len = AES_BLOCK_SIZE;
 185         rctx->cmd.u.xts.src = req->src;
 186         rctx->cmd.u.xts.src_len = req->nbytes;
 187         rctx->cmd.u.xts.dst = req->dst;
 188
 189         ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd);
 190
 191         return ret;
 192 }
 193
 194 static int ccp_aes_xts_encrypt(struct ablkcipher_request *req)
 195 {
 196         return ccp_aes_xts_crypt(req, 1);
 197 }
 198
 199 static int ccp_aes_xts_decrypt(struct ablkcipher_request *req)
 200 {
 201         return ccp_aes_xts_crypt(req, 0);
 202 }
 203
 204 static int ccp_aes_xts_cra_init(struct crypto_tfm *tfm)
 205 {
 206         struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
 207         struct crypto_sync_skcipher *fallback_tfm;
 208
 209         ctx->complete = ccp_aes_xts_complete;
 210         ctx->u.aes.key_len = 0;
 211
 212         fallback_tfm = crypto_alloc_sync_skcipher("xts(aes)", 0,
 213                                              CRYPTO_ALG_ASYNC |
 214                                              CRYPTO_ALG_NEED_FALLBACK);
 215         if (IS_ERR(fallback_tfm)) {
 216                 pr_warn("could not load fallback driver xts(aes)\n");
 217                 return PTR_ERR(fallback_tfm);
 218         }
 219         ctx->u.aes.tfm_skcipher = fallback_tfm;
 220
 221         tfm->crt_ablkcipher.reqsize = sizeof(struct ccp_aes_req_ctx);
 222
 223         return 0;
 224 }
 225
 226 static void ccp_aes_xts_cra_exit(struct crypto_tfm *tfm)
 227 {
 228         struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
 229
 230         crypto_free_sync_skcipher(ctx->u.aes.tfm_skcipher);
 231 }
 232
 233 static int ccp_register_aes_xts_alg(struct list_head *head,
 234                                     const struct ccp_aes_xts_def *def)
 235 {
 236         struct ccp_crypto_ablkcipher_alg *ccp_alg;
 237         struct crypto_alg *alg;
 238         int ret;
 239
 240         ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL);
 241         if (!ccp_alg)
 242                 return -ENOMEM;
 243
 244         INIT_LIST_HEAD(&ccp_alg->entry);
 245
 246         alg = &ccp_alg->alg;
 247
 248         snprintf(alg->cra_name, CRYPTO_MAX_ALG_NAME, "%s", def->name);
 249         snprintf(alg->cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s",
 250                  def->drv_name);
 251         alg->cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC |
 252                          CRYPTO_ALG_KERN_DRIVER_ONLY |
 253                          CRYPTO_ALG_NEED_FALLBACK;
 254         alg->cra_blocksize = AES_BLOCK_SIZE;
 255         alg->cra_ctxsize = sizeof(struct ccp_ctx);
 256         alg->cra_priority = CCP_CRA_PRIORITY;
 257         alg->cra_type = &crypto_ablkcipher_type;
 258         alg->cra_ablkcipher.setkey = ccp_aes_xts_setkey;
 259         alg->cra_ablkcipher.encrypt = ccp_aes_xts_encrypt;
 260         alg->cra_ablkcipher.decrypt = ccp_aes_xts_decrypt;
 261         alg->cra_ablkcipher.min_keysize = AES_MIN_KEY_SIZE * 2;
 262         alg->cra_ablkcipher.max_keysize = AES_MAX_KEY_SIZE * 2;
 263         alg->cra_ablkcipher.ivsize = AES_BLOCK_SIZE;
 264         alg->cra_init = ccp_aes_xts_cra_init;
 265         alg->cra_exit = ccp_aes_xts_cra_exit;
 266         alg->cra_module = THIS_MODULE;
 267
 268         ret = crypto_register_alg(alg);
 269         if (ret) {
 270                 pr_err("%s ablkcipher algorithm registration error (%d)\n",
 271                        alg->cra_name, ret);
 272                 kfree(ccp_alg);
 273                 return ret;
 274         }
 275
 276         list_add(&ccp_alg->entry, head);
 277
 278         return 0;
 279 }
 280
 281 int ccp_register_aes_xts_algs(struct list_head *head)
 282 {
 283         int i, ret;
 284
 285         for (i = 0; i < ARRAY_SIZE(aes_xts_algs); i++) {
 286                 ret = ccp_register_aes_xts_alg(head, &aes_xts_algs[i]);
 287                 if (ret)
 288                         return ret;
 289         }
 290
 291         return 0;
 292 }