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

   1 /*
   2  * AMD Cryptographic Coprocessor (CCP) AES CMAC 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/hash.h>
  21 #include <crypto/internal/hash.h>
  22 #include <crypto/scatterwalk.h>
  23
  24 #include "ccp-crypto.h"
  25
  26
  27 static int ccp_aes_cmac_complete(struct crypto_async_request *async_req,
  28                                  int ret)
  29 {
  30         struct ahash_request *req = ahash_request_cast(async_req);
  31         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
  32         struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
  33         unsigned int digest_size = crypto_ahash_digestsize(tfm);
  34
  35         if (ret)
  36                 goto e_free;
  37
  38         if (rctx->hash_rem) {
  39                 /* Save remaining data to buffer */
  40                 unsigned int offset = rctx->nbytes - rctx->hash_rem;
  41                 scatterwalk_map_and_copy(rctx->buf, rctx->src,
  42                                          offset, rctx->hash_rem, 0);
  43                 rctx->buf_count = rctx->hash_rem;
  44         } else
  45                 rctx->buf_count = 0;
  46
  47         /* Update result area if supplied */
  48         if (req->result)
  49                 memcpy(req->result, rctx->iv, digest_size);
  50
  51 e_free:
  52         sg_free_table(&rctx->data_sg);
  53
  54         return ret;
  55 }
  56
  57 static int ccp_do_cmac_update(struct ahash_request *req, unsigned int nbytes,
  58                               unsigned int final)
  59 {
  60         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
  61         struct ccp_ctx *ctx = crypto_ahash_ctx(tfm);
  62         struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
  63         struct scatterlist *sg, *cmac_key_sg = NULL;
  64         unsigned int block_size =
  65                 crypto_tfm_alg_blocksize(crypto_ahash_tfm(tfm));
  66         unsigned int need_pad, sg_count;
  67         gfp_t gfp;
  68         u64 len;
  69         int ret;
  70
  71         if (!ctx->u.aes.key_len)
  72                 return -EINVAL;
  73
  74         if (nbytes)
  75                 rctx->null_msg = 0;
  76
  77         len = (u64)rctx->buf_count + (u64)nbytes;
  78
  79         if (!final && (len <= block_size)) {
  80                 scatterwalk_map_and_copy(rctx->buf + rctx->buf_count, req->src,
  81                                          0, nbytes, 0);
  82                 rctx->buf_count += nbytes;
  83
  84                 return 0;
  85         }
  86
  87         rctx->src = req->src;
  88         rctx->nbytes = nbytes;
  89
  90         rctx->final = final;
  91         rctx->hash_rem = final ? 0 : len & (block_size - 1);
  92         rctx->hash_cnt = len - rctx->hash_rem;
  93         if (!final && !rctx->hash_rem) {
  94                 /* CCP can't do zero length final, so keep some data around */
  95                 rctx->hash_cnt -= block_size;
  96                 rctx->hash_rem = block_size;
  97         }
  98
  99         if (final && (rctx->null_msg || (len & (block_size - 1))))
 100                 need_pad = 1;
 101         else
 102                 need_pad = 0;
 103
 104         sg_init_one(&rctx->iv_sg, rctx->iv, sizeof(rctx->iv));
 105
 106         /* Build the data scatterlist table - allocate enough entries for all
 107          * possible data pieces (buffer, input data, padding)
 108          */
 109         sg_count = (nbytes) ? sg_nents(req->src) + 2 : 2;
 110         gfp = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ?
 111                 GFP_KERNEL : GFP_ATOMIC;
 112         ret = sg_alloc_table(&rctx->data_sg, sg_count, gfp);
 113         if (ret)
 114                 return ret;
 115
 116         sg = NULL;
 117         if (rctx->buf_count) {
 118                 sg_init_one(&rctx->buf_sg, rctx->buf, rctx->buf_count);
 119                 sg = ccp_crypto_sg_table_add(&rctx->data_sg, &rctx->buf_sg);
 120         }
 121
 122         if (nbytes)
 123                 sg = ccp_crypto_sg_table_add(&rctx->data_sg, req->src);
 124
 125         if (need_pad) {
 126                 int pad_length = block_size - (len & (block_size - 1));
 127
 128                 rctx->hash_cnt += pad_length;
 129
 130                 memset(rctx->pad, 0, sizeof(rctx->pad));
 131                 rctx->pad[0] = 0x80;
 132                 sg_init_one(&rctx->pad_sg, rctx->pad, pad_length);
 133                 sg = ccp_crypto_sg_table_add(&rctx->data_sg, &rctx->pad_sg);
 134         }
 135         if (sg) {
 136                 sg_mark_end(sg);
 137                 sg = rctx->data_sg.sgl;
 138         }
 139
 140         /* Initialize the K1/K2 scatterlist */
 141         if (final)
 142                 cmac_key_sg = (need_pad) ? &ctx->u.aes.k2_sg
 143                                          : &ctx->u.aes.k1_sg;
 144
 145         memset(&rctx->cmd, 0, sizeof(rctx->cmd));
 146         INIT_LIST_HEAD(&rctx->cmd.entry);
 147         rctx->cmd.engine = CCP_ENGINE_AES;
 148         rctx->cmd.u.aes.type = ctx->u.aes.type;
 149         rctx->cmd.u.aes.mode = ctx->u.aes.mode;
 150         rctx->cmd.u.aes.action = CCP_AES_ACTION_ENCRYPT;
 151         rctx->cmd.u.aes.key = &ctx->u.aes.key_sg;
 152         rctx->cmd.u.aes.key_len = ctx->u.aes.key_len;
 153         rctx->cmd.u.aes.iv = &rctx->iv_sg;
 154         rctx->cmd.u.aes.iv_len = AES_BLOCK_SIZE;
 155         rctx->cmd.u.aes.src = sg;
 156         rctx->cmd.u.aes.src_len = rctx->hash_cnt;
 157         rctx->cmd.u.aes.dst = NULL;
 158         rctx->cmd.u.aes.cmac_key = cmac_key_sg;
 159         rctx->cmd.u.aes.cmac_key_len = ctx->u.aes.kn_len;
 160         rctx->cmd.u.aes.cmac_final = final;
 161
 162         ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd);
 163
 164         return ret;
 165 }
 166
 167 static int ccp_aes_cmac_init(struct ahash_request *req)
 168 {
 169         struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
 170
 171         memset(rctx, 0, sizeof(*rctx));
 172
 173         rctx->null_msg = 1;
 174
 175         return 0;
 176 }
 177
 178 static int ccp_aes_cmac_update(struct ahash_request *req)
 179 {
 180         return ccp_do_cmac_update(req, req->nbytes, 0);
 181 }
 182
 183 static int ccp_aes_cmac_final(struct ahash_request *req)
 184 {
 185         return ccp_do_cmac_update(req, 0, 1);
 186 }
 187
 188 static int ccp_aes_cmac_finup(struct ahash_request *req)
 189 {
 190         return ccp_do_cmac_update(req, req->nbytes, 1);
 191 }
 192
 193 static int ccp_aes_cmac_digest(struct ahash_request *req)
 194 {
 195         int ret;
 196
 197         ret = ccp_aes_cmac_init(req);
 198         if (ret)
 199                 return ret;
 200
 201         return ccp_aes_cmac_finup(req);
 202 }
 203
 204 static int ccp_aes_cmac_setkey(struct crypto_ahash *tfm, const u8 *key,
 205                            unsigned int key_len)
 206 {
 207         struct ccp_ctx *ctx = crypto_tfm_ctx(crypto_ahash_tfm(tfm));
 208         struct ccp_crypto_ahash_alg *alg =
 209                 ccp_crypto_ahash_alg(crypto_ahash_tfm(tfm));
 210         u64 k0_hi, k0_lo, k1_hi, k1_lo, k2_hi, k2_lo;
 211         u64 rb_hi = 0x00, rb_lo = 0x87;
 212         __be64 *gk;
 213         int ret;
 214
 215         switch (key_len) {
 216         case AES_KEYSIZE_128:
 217                 ctx->u.aes.type = CCP_AES_TYPE_128;
 218                 break;
 219         case AES_KEYSIZE_192:
 220                 ctx->u.aes.type = CCP_AES_TYPE_192;
 221                 break;
 222         case AES_KEYSIZE_256:
 223                 ctx->u.aes.type = CCP_AES_TYPE_256;
 224                 break;
 225         default:
 226                 crypto_ahash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
 227                 return -EINVAL;
 228         }
 229         ctx->u.aes.mode = alg->mode;
 230
 231         /* Set to zero until complete */
 232         ctx->u.aes.key_len = 0;
 233
 234         /* Set the key for the AES cipher used to generate the keys */
 235         ret = crypto_cipher_setkey(ctx->u.aes.tfm_cipher, key, key_len);
 236         if (ret)
 237                 return ret;
 238
 239         /* Encrypt a block of zeroes - use key area in context */
 240         memset(ctx->u.aes.key, 0, sizeof(ctx->u.aes.key));
 241         crypto_cipher_encrypt_one(ctx->u.aes.tfm_cipher, ctx->u.aes.key,
 242                                   ctx->u.aes.key);
 243
 244         /* Generate K1 and K2 */
 245         k0_hi = be64_to_cpu(*((__be64 *)ctx->u.aes.key));
 246         k0_lo = be64_to_cpu(*((__be64 *)ctx->u.aes.key + 1));
 247
 248         k1_hi = (k0_hi << 1) | (k0_lo >> 63);
 249         k1_lo = k0_lo << 1;
 250         if (ctx->u.aes.key[0] & 0x80) {
 251                 k1_hi ^= rb_hi;
 252                 k1_lo ^= rb_lo;
 253         }
 254         gk = (__be64 *)ctx->u.aes.k1;
 255         *gk = cpu_to_be64(k1_hi);
 256         gk++;
 257         *gk = cpu_to_be64(k1_lo);
 258
 259         k2_hi = (k1_hi << 1) | (k1_lo >> 63);
 260         k2_lo = k1_lo << 1;
 261         if (ctx->u.aes.k1[0] & 0x80) {
 262                 k2_hi ^= rb_hi;
 263                 k2_lo ^= rb_lo;
 264         }
 265         gk = (__be64 *)ctx->u.aes.k2;
 266         *gk = cpu_to_be64(k2_hi);
 267         gk++;
 268         *gk = cpu_to_be64(k2_lo);
 269
 270         ctx->u.aes.kn_len = sizeof(ctx->u.aes.k1);
 271         sg_init_one(&ctx->u.aes.k1_sg, ctx->u.aes.k1, sizeof(ctx->u.aes.k1));
 272         sg_init_one(&ctx->u.aes.k2_sg, ctx->u.aes.k2, sizeof(ctx->u.aes.k2));
 273
 274         /* Save the supplied key */
 275         memset(ctx->u.aes.key, 0, sizeof(ctx->u.aes.key));
 276         memcpy(ctx->u.aes.key, key, key_len);
 277         ctx->u.aes.key_len = key_len;
 278         sg_init_one(&ctx->u.aes.key_sg, ctx->u.aes.key, key_len);
 279
 280         return ret;
 281 }
 282
 283 static int ccp_aes_cmac_cra_init(struct crypto_tfm *tfm)
 284 {
 285         struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
 286         struct crypto_ahash *ahash = __crypto_ahash_cast(tfm);
 287         struct crypto_cipher *cipher_tfm;
 288
 289         ctx->complete = ccp_aes_cmac_complete;
 290         ctx->u.aes.key_len = 0;
 291
 292         crypto_ahash_set_reqsize(ahash, sizeof(struct ccp_aes_cmac_req_ctx));
 293
 294         cipher_tfm = crypto_alloc_cipher("aes", 0,
 295                         CRYPTO_ALG_ASYNC | CRYPTO_ALG_NEED_FALLBACK);
 296         if (IS_ERR(cipher_tfm)) {
 297                 pr_warn("could not load aes cipher driver\n");
 298                 return PTR_ERR(cipher_tfm);
 299         }
 300         ctx->u.aes.tfm_cipher = cipher_tfm;
 301
 302         return 0;
 303 }
 304
 305 static void ccp_aes_cmac_cra_exit(struct crypto_tfm *tfm)
 306 {
 307         struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
 308
 309         if (ctx->u.aes.tfm_cipher)
 310                 crypto_free_cipher(ctx->u.aes.tfm_cipher);
 311         ctx->u.aes.tfm_cipher = NULL;
 312 }
 313
 314 int ccp_register_aes_cmac_algs(struct list_head *head)
 315 {
 316         struct ccp_crypto_ahash_alg *ccp_alg;
 317         struct ahash_alg *alg;
 318         struct hash_alg_common *halg;
 319         struct crypto_alg *base;
 320         int ret;
 321
 322         ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL);
 323         if (!ccp_alg)
 324                 return -ENOMEM;
 325
 326         INIT_LIST_HEAD(&ccp_alg->entry);
 327         ccp_alg->mode = CCP_AES_MODE_CMAC;
 328
 329         alg = &ccp_alg->alg;
 330         alg->init = ccp_aes_cmac_init;
 331         alg->update = ccp_aes_cmac_update;
 332         alg->final = ccp_aes_cmac_final;
 333         alg->finup = ccp_aes_cmac_finup;
 334         alg->digest = ccp_aes_cmac_digest;
 335         alg->setkey = ccp_aes_cmac_setkey;
 336
 337         halg = &alg->halg;
 338         halg->digestsize = AES_BLOCK_SIZE;
 339
 340         base = &halg->base;
 341         snprintf(base->cra_name, CRYPTO_MAX_ALG_NAME, "cmac(aes)");
 342         snprintf(base->cra_driver_name, CRYPTO_MAX_ALG_NAME, "cmac-aes-ccp");
 343         base->cra_flags = CRYPTO_ALG_TYPE_AHASH | CRYPTO_ALG_ASYNC |
 344                           CRYPTO_ALG_KERN_DRIVER_ONLY |
 345                           CRYPTO_ALG_NEED_FALLBACK;
 346         base->cra_blocksize = AES_BLOCK_SIZE;
 347         base->cra_ctxsize = sizeof(struct ccp_ctx);
 348         base->cra_priority = CCP_CRA_PRIORITY;
 349         base->cra_type = &crypto_ahash_type;
 350         base->cra_init = ccp_aes_cmac_cra_init;
 351         base->cra_exit = ccp_aes_cmac_cra_exit;
 352         base->cra_module = THIS_MODULE;
 353
 354         ret = crypto_register_ahash(alg);
 355         if (ret) {
 356                 pr_err("%s ahash algorithm registration error (%d)\n",
 357                         base->cra_name, ret);
 358                 kfree(ccp_alg);
 359                 return ret;
 360         }
 361
 362         list_add(&ccp_alg->entry, head);
 363
 364         return 0;
 365 }