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

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * AMD Cryptographic Coprocessor (CCP) AES XTS crypto API support
   4  *
   5  * Copyright (C) 2013,2017 Advanced Micro Devices, Inc.
   6  *
   7  * Author: Gary R Hook <gary.hook@amd.com>
   8  * Author: Tom Lendacky <thomas.lendacky@amd.com>
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/sched.h>
  13 #include <linux/delay.h>
  14 #include <linux/scatterlist.h>
  15 #include <crypto/aes.h>
  16 #include <crypto/xts.h>
  17 #include <crypto/internal/skcipher.h>
  18 #include <crypto/scatterwalk.h>
  19
  20 #include "ccp-crypto.h"
  21
  22 struct ccp_aes_xts_def {
  23         const char *name;
  24         const char *drv_name;
  25 };
  26
  27 static const struct ccp_aes_xts_def aes_xts_algs[] = {
  28         {
  29                 .name           = "xts(aes)",
  30                 .drv_name       = "xts-aes-ccp",
  31         },
  32 };
  33
  34 struct ccp_unit_size_map {
  35         unsigned int size;
  36         u32 value;
  37 };
  38
  39 static struct ccp_unit_size_map xts_unit_sizes[] = {
  40         {
  41                 .size   = 16,
  42                 .value  = CCP_XTS_AES_UNIT_SIZE_16,
  43         },
  44         {
  45                 .size   = 512,
  46                 .value  = CCP_XTS_AES_UNIT_SIZE_512,
  47         },
  48         {
  49                 .size   = 1024,
  50                 .value  = CCP_XTS_AES_UNIT_SIZE_1024,
  51         },
  52         {
  53                 .size   = 2048,
  54                 .value  = CCP_XTS_AES_UNIT_SIZE_2048,
  55         },
  56         {
  57                 .size   = 4096,
  58                 .value  = CCP_XTS_AES_UNIT_SIZE_4096,
  59         },
  60 };
  61
  62 static int ccp_aes_xts_complete(struct crypto_async_request *async_req, int ret)
  63 {
  64         struct skcipher_request *req = skcipher_request_cast(async_req);
  65         struct ccp_aes_req_ctx *rctx = skcipher_request_ctx(req);
  66
  67         if (ret)
  68                 return ret;
  69
  70         memcpy(req->iv, rctx->iv, AES_BLOCK_SIZE);
  71
  72         return 0;
  73 }
  74
  75 static int ccp_aes_xts_setkey(struct crypto_skcipher *tfm, const u8 *key,
  76                               unsigned int key_len)
  77 {
  78         struct ccp_ctx *ctx = crypto_skcipher_ctx(tfm);
  79         unsigned int ccpversion = ccp_version();
  80         int ret;
  81
  82         ret = xts_verify_key(tfm, key, key_len);
  83         if (ret)
  84                 return ret;
  85
  86         /* Version 3 devices support 128-bit keys; version 5 devices can
  87          * accommodate 128- and 256-bit keys.
  88          */
  89         switch (key_len) {
  90         case AES_KEYSIZE_128 * 2:
  91                 memcpy(ctx->u.aes.key, key, key_len);
  92                 break;
  93         case AES_KEYSIZE_256 * 2:
  94                 if (ccpversion > CCP_VERSION(3, 0))
  95                         memcpy(ctx->u.aes.key, key, key_len);
  96                 break;
  97         }
  98         ctx->u.aes.key_len = key_len / 2;
  99         sg_init_one(&ctx->u.aes.key_sg, ctx->u.aes.key, key_len);
 100
 101         return crypto_sync_skcipher_setkey(ctx->u.aes.tfm_skcipher, key, key_len);
 102 }
 103
 104 static int ccp_aes_xts_crypt(struct skcipher_request *req,
 105                              unsigned int encrypt)
 106 {
 107         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 108         struct ccp_ctx *ctx = crypto_skcipher_ctx(tfm);
 109         struct ccp_aes_req_ctx *rctx = skcipher_request_ctx(req);
 110         unsigned int ccpversion = ccp_version();
 111         unsigned int fallback = 0;
 112         unsigned int unit;
 113         u32 unit_size;
 114         int ret;
 115
 116         if (!ctx->u.aes.key_len)
 117                 return -EINVAL;
 118
 119         if (!req->iv)
 120                 return -EINVAL;
 121
 122         /* Check conditions under which the CCP can fulfill a request. The
 123          * device can handle input plaintext of a length that is a multiple
 124          * of the unit_size, bug the crypto implementation only supports
 125          * the unit_size being equal to the input length. This limits the
 126          * number of scenarios we can handle.
 127          */
 128         unit_size = CCP_XTS_AES_UNIT_SIZE__LAST;
 129         for (unit = 0; unit < ARRAY_SIZE(xts_unit_sizes); unit++) {
 130                 if (req->cryptlen == xts_unit_sizes[unit].size) {
 131                         unit_size = unit;
 132                         break;
 133                 }
 134         }
 135         /* The CCP has restrictions on block sizes. Also, a version 3 device
 136          * only supports AES-128 operations; version 5 CCPs support both
 137          * AES-128 and -256 operations.
 138          */
 139         if (unit_size == CCP_XTS_AES_UNIT_SIZE__LAST)
 140                 fallback = 1;
 141         if ((ccpversion < CCP_VERSION(5, 0)) &&
 142             (ctx->u.aes.key_len != AES_KEYSIZE_128))
 143                 fallback = 1;
 144         if ((ctx->u.aes.key_len != AES_KEYSIZE_128) &&
 145             (ctx->u.aes.key_len != AES_KEYSIZE_256))
 146                 fallback = 1;
 147         if (fallback) {
 148                 SYNC_SKCIPHER_REQUEST_ON_STACK(subreq,
 149                                                ctx->u.aes.tfm_skcipher);
 150
 151                 /* Use the fallback to process the request for any
 152                  * unsupported unit sizes or key sizes
 153                  */
 154                 skcipher_request_set_sync_tfm(subreq, ctx->u.aes.tfm_skcipher);
 155                 skcipher_request_set_callback(subreq, req->base.flags,
 156                                               NULL, NULL);
 157                 skcipher_request_set_crypt(subreq, req->src, req->dst,
 158                                            req->cryptlen, req->iv);
 159                 ret = encrypt ? crypto_skcipher_encrypt(subreq) :
 160                                 crypto_skcipher_decrypt(subreq);
 161                 skcipher_request_zero(subreq);
 162                 return ret;
 163         }
 164
 165         memcpy(rctx->iv, req->iv, AES_BLOCK_SIZE);
 166         sg_init_one(&rctx->iv_sg, rctx->iv, AES_BLOCK_SIZE);
 167
 168         memset(&rctx->cmd, 0, sizeof(rctx->cmd));
 169         INIT_LIST_HEAD(&rctx->cmd.entry);
 170         rctx->cmd.engine = CCP_ENGINE_XTS_AES_128;
 171         rctx->cmd.u.xts.type = CCP_AES_TYPE_128;
 172         rctx->cmd.u.xts.action = (encrypt) ? CCP_AES_ACTION_ENCRYPT
 173                                            : CCP_AES_ACTION_DECRYPT;
 174         rctx->cmd.u.xts.unit_size = unit_size;
 175         rctx->cmd.u.xts.key = &ctx->u.aes.key_sg;
 176         rctx->cmd.u.xts.key_len = ctx->u.aes.key_len;
 177         rctx->cmd.u.xts.iv = &rctx->iv_sg;
 178         rctx->cmd.u.xts.iv_len = AES_BLOCK_SIZE;
 179         rctx->cmd.u.xts.src = req->src;
 180         rctx->cmd.u.xts.src_len = req->cryptlen;
 181         rctx->cmd.u.xts.dst = req->dst;
 182
 183         ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd);
 184
 185         return ret;
 186 }
 187
 188 static int ccp_aes_xts_encrypt(struct skcipher_request *req)
 189 {
 190         return ccp_aes_xts_crypt(req, 1);
 191 }
 192
 193 static int ccp_aes_xts_decrypt(struct skcipher_request *req)
 194 {
 195         return ccp_aes_xts_crypt(req, 0);
 196 }
 197
 198 static int ccp_aes_xts_init_tfm(struct crypto_skcipher *tfm)
 199 {
 200         struct ccp_ctx *ctx = crypto_skcipher_ctx(tfm);
 201         struct crypto_sync_skcipher *fallback_tfm;
 202
 203         ctx->complete = ccp_aes_xts_complete;
 204         ctx->u.aes.key_len = 0;
 205
 206         fallback_tfm = crypto_alloc_sync_skcipher("xts(aes)", 0,
 207                                              CRYPTO_ALG_ASYNC |
 208                                              CRYPTO_ALG_NEED_FALLBACK);
 209         if (IS_ERR(fallback_tfm)) {
 210                 pr_warn("could not load fallback driver xts(aes)\n");
 211                 return PTR_ERR(fallback_tfm);
 212         }
 213         ctx->u.aes.tfm_skcipher = fallback_tfm;
 214
 215         crypto_skcipher_set_reqsize(tfm, sizeof(struct ccp_aes_req_ctx));
 216
 217         return 0;
 218 }
 219
 220 static void ccp_aes_xts_exit_tfm(struct crypto_skcipher *tfm)
 221 {
 222         struct ccp_ctx *ctx = crypto_skcipher_ctx(tfm);
 223
 224         crypto_free_sync_skcipher(ctx->u.aes.tfm_skcipher);
 225 }
 226
 227 static int ccp_register_aes_xts_alg(struct list_head *head,
 228                                     const struct ccp_aes_xts_def *def)
 229 {
 230         struct ccp_crypto_skcipher_alg *ccp_alg;
 231         struct skcipher_alg *alg;
 232         int ret;
 233
 234         ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL);
 235         if (!ccp_alg)
 236                 return -ENOMEM;
 237
 238         INIT_LIST_HEAD(&ccp_alg->entry);
 239
 240         alg = &ccp_alg->alg;
 241
 242         snprintf(alg->base.cra_name, CRYPTO_MAX_ALG_NAME, "%s", def->name);
 243         snprintf(alg->base.cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s",
 244                  def->drv_name);
 245         alg->base.cra_flags     = CRYPTO_ALG_ASYNC |
 246                                   CRYPTO_ALG_KERN_DRIVER_ONLY |
 247                                   CRYPTO_ALG_NEED_FALLBACK;
 248         alg->base.cra_blocksize = AES_BLOCK_SIZE;
 249         alg->base.cra_ctxsize   = sizeof(struct ccp_ctx);
 250         alg->base.cra_priority  = CCP_CRA_PRIORITY;
 251         alg->base.cra_module    = THIS_MODULE;
 252
 253         alg->setkey             = ccp_aes_xts_setkey;
 254         alg->encrypt            = ccp_aes_xts_encrypt;
 255         alg->decrypt            = ccp_aes_xts_decrypt;
 256         alg->min_keysize        = AES_MIN_KEY_SIZE * 2;
 257         alg->max_keysize        = AES_MAX_KEY_SIZE * 2;
 258         alg->ivsize             = AES_BLOCK_SIZE;
 259         alg->init               = ccp_aes_xts_init_tfm;
 260         alg->exit               = ccp_aes_xts_exit_tfm;
 261
 262         ret = crypto_register_skcipher(alg);
 263         if (ret) {
 264                 pr_err("%s skcipher algorithm registration error (%d)\n",
 265                        alg->base.cra_name, ret);
 266                 kfree(ccp_alg);
 267                 return ret;
 268         }
 269
 270         list_add(&ccp_alg->entry, head);
 271
 272         return 0;
 273 }
 274
 275 int ccp_register_aes_xts_algs(struct list_head *head)
 276 {
 277         int i, ret;
 278
 279         for (i = 0; i < ARRAY_SIZE(aes_xts_algs); i++) {
 280                 ret = ccp_register_aes_xts_alg(head, &aes_xts_algs[i]);
 281                 if (ret)
 282                         return ret;
 283         }
 284
 285         return 0;
 286 }