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 static int ccp_aes_cmac_complete(struct crypto_async_request *async_req,
  27                                  int ret)
  28 {
  29         struct ahash_request *req = ahash_request_cast(async_req);
  30         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
  31         struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
  32         unsigned int digest_size = crypto_ahash_digestsize(tfm);
  33
  34         if (ret)
  35                 goto e_free;
  36
  37         if (rctx->hash_rem) {
  38                 /* Save remaining data to buffer */
  39                 unsigned int offset = rctx->nbytes - rctx->hash_rem;
  40
  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
  48         /* Update result area if supplied */
  49         if (req->result)
  50                 memcpy(req->result, rctx->iv, digest_size);
  51
  52 e_free:
  53         sg_free_table(&rctx->data_sg);
  54
  55         return ret;
  56 }
  57
  58 static int ccp_do_cmac_update(struct ahash_request *req, unsigned int nbytes,
  59                               unsigned int final)
  60 {
  61         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
  62         struct ccp_ctx *ctx = crypto_ahash_ctx(tfm);
  63         struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
  64         struct scatterlist *sg, *cmac_key_sg = NULL;
  65         unsigned int block_size =
  66                 crypto_tfm_alg_blocksize(crypto_ahash_tfm(tfm));
  67         unsigned int need_pad, sg_count;
  68         gfp_t gfp;
  69         u64 len;
  70         int ret;
  71
  72         if (!ctx->u.aes.key_len)
  73                 return -EINVAL;
  74
  75         if (nbytes)
  76                 rctx->null_msg = 0;
  77
  78         len = (u64)rctx->buf_count + (u64)nbytes;
  79
  80         if (!final && (len <= block_size)) {
  81                 scatterwalk_map_and_copy(rctx->buf + rctx->buf_count, req->src,
  82                                          0, nbytes, 0);
  83                 rctx->buf_count += nbytes;
  84
  85                 return 0;
  86         }
  87
  88         rctx->src = req->src;
  89         rctx->nbytes = nbytes;
  90
  91         rctx->final = final;
  92         rctx->hash_rem = final ? 0 : len & (block_size - 1);
  93         rctx->hash_cnt = len - rctx->hash_rem;
  94         if (!final && !rctx->hash_rem) {
  95                 /* CCP can't do zero length final, so keep some data around */
  96                 rctx->hash_cnt -= block_size;
  97                 rctx->hash_rem = block_size;
  98         }
  99
 100         if (final && (rctx->null_msg || (len & (block_size - 1))))
 101                 need_pad = 1;
 102         else
 103                 need_pad = 0;
 104
 105         sg_init_one(&rctx->iv_sg, rctx->iv, sizeof(rctx->iv));
 106
 107         /* Build the data scatterlist table - allocate enough entries for all
 108          * possible data pieces (buffer, input data, padding)
 109          */
 110         sg_count = (nbytes) ? sg_nents(req->src) + 2 : 2;
 111         gfp = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ?
 112                 GFP_KERNEL : GFP_ATOMIC;
 113         ret = sg_alloc_table(&rctx->data_sg, sg_count, gfp);
 114         if (ret)
 115                 return ret;
 116
 117         sg = NULL;
 118         if (rctx->buf_count) {
 119                 sg_init_one(&rctx->buf_sg, rctx->buf, rctx->buf_count);
 120                 sg = ccp_crypto_sg_table_add(&rctx->data_sg, &rctx->buf_sg);
 121         }
 122
 123         if (nbytes)
 124                 sg = ccp_crypto_sg_table_add(&rctx->data_sg, req->src);
 125
 126         if (need_pad) {
 127                 int pad_length = block_size - (len & (block_size - 1));
 128
 129                 rctx->hash_cnt += pad_length;
 130
 131                 memset(rctx->pad, 0, sizeof(rctx->pad));
 132                 rctx->pad[0] = 0x80;
 133                 sg_init_one(&rctx->pad_sg, rctx->pad, pad_length);
 134                 sg = ccp_crypto_sg_table_add(&rctx->data_sg, &rctx->pad_sg);
 135         }
 136         if (sg) {
 137                 sg_mark_end(sg);
 138                 sg = rctx->data_sg.sgl;
 139         }
 140
 141         /* Initialize the K1/K2 scatterlist */
 142         if (final)
 143                 cmac_key_sg = (need_pad) ? &ctx->u.aes.k2_sg
 144                                          : &ctx->u.aes.k1_sg;
 145
 146         memset(&rctx->cmd, 0, sizeof(rctx->cmd));
 147         INIT_LIST_HEAD(&rctx->cmd.entry);
 148         rctx->cmd.engine = CCP_ENGINE_AES;
 149         rctx->cmd.u.aes.type = ctx->u.aes.type;
 150         rctx->cmd.u.aes.mode = ctx->u.aes.mode;
 151         rctx->cmd.u.aes.action = CCP_AES_ACTION_ENCRYPT;
 152         rctx->cmd.u.aes.key = &ctx->u.aes.key_sg;
 153         rctx->cmd.u.aes.key_len = ctx->u.aes.key_len;
 154         rctx->cmd.u.aes.iv = &rctx->iv_sg;
 155         rctx->cmd.u.aes.iv_len = AES_BLOCK_SIZE;
 156         rctx->cmd.u.aes.src = sg;
 157         rctx->cmd.u.aes.src_len = rctx->hash_cnt;
 158         rctx->cmd.u.aes.dst = NULL;
 159         rctx->cmd.u.aes.cmac_key = cmac_key_sg;
 160         rctx->cmd.u.aes.cmac_key_len = ctx->u.aes.kn_len;
 161         rctx->cmd.u.aes.cmac_final = final;
 162
 163         ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd);
 164
 165         return ret;
 166 }
 167
 168 static int ccp_aes_cmac_init(struct ahash_request *req)
 169 {
 170         struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
 171
 172         memset(rctx, 0, sizeof(*rctx));
 173
 174         rctx->null_msg = 1;
 175
 176         return 0;
 177 }
 178
 179 static int ccp_aes_cmac_update(struct ahash_request *req)
 180 {
 181         return ccp_do_cmac_update(req, req->nbytes, 0);
 182 }
 183
 184 static int ccp_aes_cmac_final(struct ahash_request *req)
 185 {
 186         return ccp_do_cmac_update(req, 0, 1);
 187 }
 188
 189 static int ccp_aes_cmac_finup(struct ahash_request *req)
 190 {
 191         return ccp_do_cmac_update(req, req->nbytes, 1);
 192 }
 193
 194 static int ccp_aes_cmac_digest(struct ahash_request *req)
 195 {
 196         int ret;
 197
 198         ret = ccp_aes_cmac_init(req);
 199         if (ret)
 200                 return ret;
 201
 202         return ccp_aes_cmac_finup(req);
 203 }
 204
 205 static int ccp_aes_cmac_setkey(struct crypto_ahash *tfm, const u8 *key,
 206                                unsigned int key_len)
 207 {
 208         struct ccp_ctx *ctx = crypto_tfm_ctx(crypto_ahash_tfm(tfm));
 209         struct ccp_crypto_ahash_alg *alg =
 210                 ccp_crypto_ahash_alg(crypto_ahash_tfm(tfm));
 211         u64 k0_hi, k0_lo, k1_hi, k1_lo, k2_hi, k2_lo;
 212         u64 rb_hi = 0x00, rb_lo = 0x87;
 213         __be64 *gk;
 214         int ret;
 215
 216         switch (key_len) {
 217         case AES_KEYSIZE_128:
 218                 ctx->u.aes.type = CCP_AES_TYPE_128;
 219                 break;
 220         case AES_KEYSIZE_192:
 221                 ctx->u.aes.type = CCP_AES_TYPE_192;
 222                 break;
 223         case AES_KEYSIZE_256:
 224                 ctx->u.aes.type = CCP_AES_TYPE_256;
 225                 break;
 226         default:
 227                 crypto_ahash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
 228                 return -EINVAL;
 229         }
 230         ctx->u.aes.mode = alg->mode;
 231
 232         /* Set to zero until complete */
 233         ctx->u.aes.key_len = 0;
 234
 235         /* Set the key for the AES cipher used to generate the keys */
 236         ret = crypto_cipher_setkey(ctx->u.aes.tfm_cipher, key, key_len);
 237         if (ret)
 238                 return ret;
 239
 240         /* Encrypt a block of zeroes - use key area in context */
 241         memset(ctx->u.aes.key, 0, sizeof(ctx->u.aes.key));
 242         crypto_cipher_encrypt_one(ctx->u.aes.tfm_cipher, ctx->u.aes.key,
 243                                   ctx->u.aes.key);
 244
 245         /* Generate K1 and K2 */
 246         k0_hi = be64_to_cpu(*((__be64 *)ctx->u.aes.key));
 247         k0_lo = be64_to_cpu(*((__be64 *)ctx->u.aes.key + 1));
 248
 249         k1_hi = (k0_hi << 1) | (k0_lo >> 63);
 250         k1_lo = k0_lo << 1;
 251         if (ctx->u.aes.key[0] & 0x80) {
 252                 k1_hi ^= rb_hi;
 253                 k1_lo ^= rb_lo;
 254         }
 255         gk = (__be64 *)ctx->u.aes.k1;
 256         *gk = cpu_to_be64(k1_hi);
 257         gk++;
 258         *gk = cpu_to_be64(k1_lo);
 259
 260         k2_hi = (k1_hi << 1) | (k1_lo >> 63);
 261         k2_lo = k1_lo << 1;
 262         if (ctx->u.aes.k1[0] & 0x80) {
 263                 k2_hi ^= rb_hi;
 264                 k2_lo ^= rb_lo;
 265         }
 266         gk = (__be64 *)ctx->u.aes.k2;
 267         *gk = cpu_to_be64(k2_hi);
 268         gk++;
 269         *gk = cpu_to_be64(k2_lo);
 270
 271         ctx->u.aes.kn_len = sizeof(ctx->u.aes.k1);
 272         sg_init_one(&ctx->u.aes.k1_sg, ctx->u.aes.k1, sizeof(ctx->u.aes.k1));
 273         sg_init_one(&ctx->u.aes.k2_sg, ctx->u.aes.k2, sizeof(ctx->u.aes.k2));
 274
 275         /* Save the supplied key */
 276         memset(ctx->u.aes.key, 0, sizeof(ctx->u.aes.key));
 277         memcpy(ctx->u.aes.key, key, key_len);
 278         ctx->u.aes.key_len = key_len;
 279         sg_init_one(&ctx->u.aes.key_sg, ctx->u.aes.key, key_len);
 280
 281         return ret;
 282 }
 283
 284 static int ccp_aes_cmac_cra_init(struct crypto_tfm *tfm)
 285 {
 286         struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
 287         struct crypto_ahash *ahash = __crypto_ahash_cast(tfm);
 288         struct crypto_cipher *cipher_tfm;
 289
 290         ctx->complete = ccp_aes_cmac_complete;
 291         ctx->u.aes.key_len = 0;
 292
 293         crypto_ahash_set_reqsize(ahash, sizeof(struct ccp_aes_cmac_req_ctx));
 294
 295         cipher_tfm = crypto_alloc_cipher("aes", 0,
 296                                          CRYPTO_ALG_ASYNC |
 297                                          CRYPTO_ALG_NEED_FALLBACK);
 298         if (IS_ERR(cipher_tfm)) {
 299                 pr_warn("could not load aes cipher driver\n");
 300                 return PTR_ERR(cipher_tfm);
 301         }
 302         ctx->u.aes.tfm_cipher = cipher_tfm;
 303
 304         return 0;
 305 }
 306
 307 static void ccp_aes_cmac_cra_exit(struct crypto_tfm *tfm)
 308 {
 309         struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
 310
 311         if (ctx->u.aes.tfm_cipher)
 312                 crypto_free_cipher(ctx->u.aes.tfm_cipher);
 313         ctx->u.aes.tfm_cipher = NULL;
 314 }
 315
 316 int ccp_register_aes_cmac_algs(struct list_head *head)
 317 {
 318         struct ccp_crypto_ahash_alg *ccp_alg;
 319         struct ahash_alg *alg;
 320         struct hash_alg_common *halg;
 321         struct crypto_alg *base;
 322         int ret;
 323
 324         ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL);
 325         if (!ccp_alg)
 326                 return -ENOMEM;
 327
 328         INIT_LIST_HEAD(&ccp_alg->entry);
 329         ccp_alg->mode = CCP_AES_MODE_CMAC;
 330
 331         alg = &ccp_alg->alg;
 332         alg->init = ccp_aes_cmac_init;
 333         alg->update = ccp_aes_cmac_update;
 334         alg->final = ccp_aes_cmac_final;
 335         alg->finup = ccp_aes_cmac_finup;
 336         alg->digest = ccp_aes_cmac_digest;
 337         alg->setkey = ccp_aes_cmac_setkey;
 338
 339         halg = &alg->halg;
 340         halg->digestsize = AES_BLOCK_SIZE;
 341
 342         base = &halg->base;
 343         snprintf(base->cra_name, CRYPTO_MAX_ALG_NAME, "cmac(aes)");
 344         snprintf(base->cra_driver_name, CRYPTO_MAX_ALG_NAME, "cmac-aes-ccp");
 345         base->cra_flags = CRYPTO_ALG_TYPE_AHASH | CRYPTO_ALG_ASYNC |
 346                           CRYPTO_ALG_KERN_DRIVER_ONLY |
 347                           CRYPTO_ALG_NEED_FALLBACK;
 348         base->cra_blocksize = AES_BLOCK_SIZE;
 349         base->cra_ctxsize = sizeof(struct ccp_ctx);
 350         base->cra_priority = CCP_CRA_PRIORITY;
 351         base->cra_type = &crypto_ahash_type;
 352         base->cra_init = ccp_aes_cmac_cra_init;
 353         base->cra_exit = ccp_aes_cmac_cra_exit;
 354         base->cra_module = THIS_MODULE;
 355
 356         ret = crypto_register_ahash(alg);
 357         if (ret) {
 358                 pr_err("%s ahash algorithm registration error (%d)\n",
 359                        base->cra_name, ret);
 360                 kfree(ccp_alg);
 361                 return ret;
 362         }
 363
 364         list_add(&ccp_alg->entry, head);
 365
 366         return 0;
 367 }