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

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * AMD Cryptographic Coprocessor (CCP) AES CMAC crypto API support
   4  *
   5  * Copyright (C) 2013,2018 Advanced Micro Devices, Inc.
   6  *
   7  * Author: Tom Lendacky <thomas.lendacky@amd.com>
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/sched.h>
  12 #include <linux/delay.h>
  13 #include <linux/scatterlist.h>
  14 #include <linux/crypto.h>
  15 #include <crypto/algapi.h>
  16 #include <crypto/aes.h>
  17 #include <crypto/hash.h>
  18 #include <crypto/internal/hash.h>
  19 #include <crypto/scatterwalk.h>
  20
  21 #include "ccp-crypto.h"
  22
  23 static int ccp_aes_cmac_complete(struct crypto_async_request *async_req,
  24                                  int ret)
  25 {
  26         struct ahash_request *req = ahash_request_cast(async_req);
  27         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
  28         struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
  29         unsigned int digest_size = crypto_ahash_digestsize(tfm);
  30
  31         if (ret)
  32                 goto e_free;
  33
  34         if (rctx->hash_rem) {
  35                 /* Save remaining data to buffer */
  36                 unsigned int offset = rctx->nbytes - rctx->hash_rem;
  37
  38                 scatterwalk_map_and_copy(rctx->buf, rctx->src,
  39                                          offset, rctx->hash_rem, 0);
  40                 rctx->buf_count = rctx->hash_rem;
  41         } else {
  42                 rctx->buf_count = 0;
  43         }
  44
  45         /* Update result area if supplied */
  46         if (req->result && rctx->final)
  47                 memcpy(req->result, rctx->iv, digest_size);
  48
  49 e_free:
  50         sg_free_table(&rctx->data_sg);
  51
  52         return ret;
  53 }
  54
  55 static int ccp_do_cmac_update(struct ahash_request *req, unsigned int nbytes,
  56                               unsigned int final)
  57 {
  58         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
  59         struct ccp_ctx *ctx = crypto_ahash_ctx(tfm);
  60         struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
  61         struct scatterlist *sg, *cmac_key_sg = NULL;
  62         unsigned int block_size =
  63                 crypto_tfm_alg_blocksize(crypto_ahash_tfm(tfm));
  64         unsigned int need_pad, sg_count;
  65         gfp_t gfp;
  66         u64 len;
  67         int ret;
  68
  69         if (!ctx->u.aes.key_len)
  70                 return -EINVAL;
  71
  72         if (nbytes)
  73                 rctx->null_msg = 0;
  74
  75         len = (u64)rctx->buf_count + (u64)nbytes;
  76
  77         if (!final && (len <= block_size)) {
  78                 scatterwalk_map_and_copy(rctx->buf + rctx->buf_count, req->src,
  79                                          0, nbytes, 0);
  80                 rctx->buf_count += nbytes;
  81
  82                 return 0;
  83         }
  84
  85         rctx->src = req->src;
  86         rctx->nbytes = nbytes;
  87
  88         rctx->final = final;
  89         rctx->hash_rem = final ? 0 : len & (block_size - 1);
  90         rctx->hash_cnt = len - rctx->hash_rem;
  91         if (!final && !rctx->hash_rem) {
  92                 /* CCP can't do zero length final, so keep some data around */
  93                 rctx->hash_cnt -= block_size;
  94                 rctx->hash_rem = block_size;
  95         }
  96
  97         if (final && (rctx->null_msg || (len & (block_size - 1))))
  98                 need_pad = 1;
  99         else
 100                 need_pad = 0;
 101
 102         sg_init_one(&rctx->iv_sg, rctx->iv, sizeof(rctx->iv));
 103
 104         /* Build the data scatterlist table - allocate enough entries for all
 105          * possible data pieces (buffer, input data, padding)
 106          */
 107         sg_count = (nbytes) ? sg_nents(req->src) + 2 : 2;
 108         gfp = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ?
 109                 GFP_KERNEL : GFP_ATOMIC;
 110         ret = sg_alloc_table(&rctx->data_sg, sg_count, gfp);
 111         if (ret)
 112                 return ret;
 113
 114         sg = NULL;
 115         if (rctx->buf_count) {
 116                 sg_init_one(&rctx->buf_sg, rctx->buf, rctx->buf_count);
 117                 sg = ccp_crypto_sg_table_add(&rctx->data_sg, &rctx->buf_sg);
 118                 if (!sg) {
 119                         ret = -EINVAL;
 120                         goto e_free;
 121                 }
 122         }
 123
 124         if (nbytes) {
 125                 sg = ccp_crypto_sg_table_add(&rctx->data_sg, req->src);
 126                 if (!sg) {
 127                         ret = -EINVAL;
 128                         goto e_free;
 129                 }
 130         }
 131
 132         if (need_pad) {
 133                 int pad_length = block_size - (len & (block_size - 1));
 134
 135                 rctx->hash_cnt += pad_length;
 136
 137                 memset(rctx->pad, 0, sizeof(rctx->pad));
 138                 rctx->pad[0] = 0x80;
 139                 sg_init_one(&rctx->pad_sg, rctx->pad, pad_length);
 140                 sg = ccp_crypto_sg_table_add(&rctx->data_sg, &rctx->pad_sg);
 141                 if (!sg) {
 142                         ret = -EINVAL;
 143                         goto e_free;
 144                 }
 145         }
 146         if (sg) {
 147                 sg_mark_end(sg);
 148                 sg = rctx->data_sg.sgl;
 149         }
 150
 151         /* Initialize the K1/K2 scatterlist */
 152         if (final)
 153                 cmac_key_sg = (need_pad) ? &ctx->u.aes.k2_sg
 154                                          : &ctx->u.aes.k1_sg;
 155
 156         memset(&rctx->cmd, 0, sizeof(rctx->cmd));
 157         INIT_LIST_HEAD(&rctx->cmd.entry);
 158         rctx->cmd.engine = CCP_ENGINE_AES;
 159         rctx->cmd.u.aes.type = ctx->u.aes.type;
 160         rctx->cmd.u.aes.mode = ctx->u.aes.mode;
 161         rctx->cmd.u.aes.action = CCP_AES_ACTION_ENCRYPT;
 162         rctx->cmd.u.aes.key = &ctx->u.aes.key_sg;
 163         rctx->cmd.u.aes.key_len = ctx->u.aes.key_len;
 164         rctx->cmd.u.aes.iv = &rctx->iv_sg;
 165         rctx->cmd.u.aes.iv_len = AES_BLOCK_SIZE;
 166         rctx->cmd.u.aes.src = sg;
 167         rctx->cmd.u.aes.src_len = rctx->hash_cnt;
 168         rctx->cmd.u.aes.dst = NULL;
 169         rctx->cmd.u.aes.cmac_key = cmac_key_sg;
 170         rctx->cmd.u.aes.cmac_key_len = ctx->u.aes.kn_len;
 171         rctx->cmd.u.aes.cmac_final = final;
 172
 173         ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd);
 174
 175         return ret;
 176
 177 e_free:
 178         sg_free_table(&rctx->data_sg);
 179
 180         return ret;
 181 }
 182
 183 static int ccp_aes_cmac_init(struct ahash_request *req)
 184 {
 185         struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
 186
 187         memset(rctx, 0, sizeof(*rctx));
 188
 189         rctx->null_msg = 1;
 190
 191         return 0;
 192 }
 193
 194 static int ccp_aes_cmac_update(struct ahash_request *req)
 195 {
 196         return ccp_do_cmac_update(req, req->nbytes, 0);
 197 }
 198
 199 static int ccp_aes_cmac_final(struct ahash_request *req)
 200 {
 201         return ccp_do_cmac_update(req, 0, 1);
 202 }
 203
 204 static int ccp_aes_cmac_finup(struct ahash_request *req)
 205 {
 206         return ccp_do_cmac_update(req, req->nbytes, 1);
 207 }
 208
 209 static int ccp_aes_cmac_digest(struct ahash_request *req)
 210 {
 211         int ret;
 212
 213         ret = ccp_aes_cmac_init(req);
 214         if (ret)
 215                 return ret;
 216
 217         return ccp_aes_cmac_finup(req);
 218 }
 219
 220 static int ccp_aes_cmac_export(struct ahash_request *req, void *out)
 221 {
 222         struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
 223         struct ccp_aes_cmac_exp_ctx state;
 224
 225         /* Don't let anything leak to 'out' */
 226         memset(&state, 0, sizeof(state));
 227
 228         state.null_msg = rctx->null_msg;
 229         memcpy(state.iv, rctx->iv, sizeof(state.iv));
 230         state.buf_count = rctx->buf_count;
 231         memcpy(state.buf, rctx->buf, sizeof(state.buf));
 232
 233         /* 'out' may not be aligned so memcpy from local variable */
 234         memcpy(out, &state, sizeof(state));
 235
 236         return 0;
 237 }
 238
 239 static int ccp_aes_cmac_import(struct ahash_request *req, const void *in)
 240 {
 241         struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx(req);
 242         struct ccp_aes_cmac_exp_ctx state;
 243
 244         /* 'in' may not be aligned so memcpy to local variable */
 245         memcpy(&state, in, sizeof(state));
 246
 247         memset(rctx, 0, sizeof(*rctx));
 248         rctx->null_msg = state.null_msg;
 249         memcpy(rctx->iv, state.iv, sizeof(rctx->iv));
 250         rctx->buf_count = state.buf_count;
 251         memcpy(rctx->buf, state.buf, sizeof(rctx->buf));
 252
 253         return 0;
 254 }
 255
 256 static int ccp_aes_cmac_setkey(struct crypto_ahash *tfm, const u8 *key,
 257                                unsigned int key_len)
 258 {
 259         struct ccp_ctx *ctx = crypto_tfm_ctx(crypto_ahash_tfm(tfm));
 260         struct ccp_crypto_ahash_alg *alg =
 261                 ccp_crypto_ahash_alg(crypto_ahash_tfm(tfm));
 262         u64 k0_hi, k0_lo, k1_hi, k1_lo, k2_hi, k2_lo;
 263         u64 rb_hi = 0x00, rb_lo = 0x87;
 264         struct crypto_aes_ctx aes;
 265         __be64 *gk;
 266         int ret;
 267
 268         switch (key_len) {
 269         case AES_KEYSIZE_128:
 270                 ctx->u.aes.type = CCP_AES_TYPE_128;
 271                 break;
 272         case AES_KEYSIZE_192:
 273                 ctx->u.aes.type = CCP_AES_TYPE_192;
 274                 break;
 275         case AES_KEYSIZE_256:
 276                 ctx->u.aes.type = CCP_AES_TYPE_256;
 277                 break;
 278         default:
 279                 return -EINVAL;
 280         }
 281         ctx->u.aes.mode = alg->mode;
 282
 283         /* Set to zero until complete */
 284         ctx->u.aes.key_len = 0;
 285
 286         /* Set the key for the AES cipher used to generate the keys */
 287         ret = aes_expandkey(&aes, key, key_len);
 288         if (ret)
 289                 return ret;
 290
 291         /* Encrypt a block of zeroes - use key area in context */
 292         memset(ctx->u.aes.key, 0, sizeof(ctx->u.aes.key));
 293         aes_encrypt(&aes, ctx->u.aes.key, ctx->u.aes.key);
 294         memzero_explicit(&aes, sizeof(aes));
 295
 296         /* Generate K1 and K2 */
 297         k0_hi = be64_to_cpu(*((__be64 *)ctx->u.aes.key));
 298         k0_lo = be64_to_cpu(*((__be64 *)ctx->u.aes.key + 1));
 299
 300         k1_hi = (k0_hi << 1) | (k0_lo >> 63);
 301         k1_lo = k0_lo << 1;
 302         if (ctx->u.aes.key[0] & 0x80) {
 303                 k1_hi ^= rb_hi;
 304                 k1_lo ^= rb_lo;
 305         }
 306         gk = (__be64 *)ctx->u.aes.k1;
 307         *gk = cpu_to_be64(k1_hi);
 308         gk++;
 309         *gk = cpu_to_be64(k1_lo);
 310
 311         k2_hi = (k1_hi << 1) | (k1_lo >> 63);
 312         k2_lo = k1_lo << 1;
 313         if (ctx->u.aes.k1[0] & 0x80) {
 314                 k2_hi ^= rb_hi;
 315                 k2_lo ^= rb_lo;
 316         }
 317         gk = (__be64 *)ctx->u.aes.k2;
 318         *gk = cpu_to_be64(k2_hi);
 319         gk++;
 320         *gk = cpu_to_be64(k2_lo);
 321
 322         ctx->u.aes.kn_len = sizeof(ctx->u.aes.k1);
 323         sg_init_one(&ctx->u.aes.k1_sg, ctx->u.aes.k1, sizeof(ctx->u.aes.k1));
 324         sg_init_one(&ctx->u.aes.k2_sg, ctx->u.aes.k2, sizeof(ctx->u.aes.k2));
 325
 326         /* Save the supplied key */
 327         memset(ctx->u.aes.key, 0, sizeof(ctx->u.aes.key));
 328         memcpy(ctx->u.aes.key, key, key_len);
 329         ctx->u.aes.key_len = key_len;
 330         sg_init_one(&ctx->u.aes.key_sg, ctx->u.aes.key, key_len);
 331
 332         return ret;
 333 }
 334
 335 static int ccp_aes_cmac_cra_init(struct crypto_tfm *tfm)
 336 {
 337         struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
 338         struct crypto_ahash *ahash = __crypto_ahash_cast(tfm);
 339
 340         ctx->complete = ccp_aes_cmac_complete;
 341         ctx->u.aes.key_len = 0;
 342
 343         crypto_ahash_set_reqsize(ahash, sizeof(struct ccp_aes_cmac_req_ctx));
 344
 345         return 0;
 346 }
 347
 348 int ccp_register_aes_cmac_algs(struct list_head *head)
 349 {
 350         struct ccp_crypto_ahash_alg *ccp_alg;
 351         struct ahash_alg *alg;
 352         struct hash_alg_common *halg;
 353         struct crypto_alg *base;
 354         int ret;
 355
 356         ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL);
 357         if (!ccp_alg)
 358                 return -ENOMEM;
 359
 360         INIT_LIST_HEAD(&ccp_alg->entry);
 361         ccp_alg->mode = CCP_AES_MODE_CMAC;
 362
 363         alg = &ccp_alg->alg;
 364         alg->init = ccp_aes_cmac_init;
 365         alg->update = ccp_aes_cmac_update;
 366         alg->final = ccp_aes_cmac_final;
 367         alg->finup = ccp_aes_cmac_finup;
 368         alg->digest = ccp_aes_cmac_digest;
 369         alg->export = ccp_aes_cmac_export;
 370         alg->import = ccp_aes_cmac_import;
 371         alg->setkey = ccp_aes_cmac_setkey;
 372
 373         halg = &alg->halg;
 374         halg->digestsize = AES_BLOCK_SIZE;
 375         halg->statesize = sizeof(struct ccp_aes_cmac_exp_ctx);
 376
 377         base = &halg->base;
 378         snprintf(base->cra_name, CRYPTO_MAX_ALG_NAME, "cmac(aes)");
 379         snprintf(base->cra_driver_name, CRYPTO_MAX_ALG_NAME, "cmac-aes-ccp");
 380         base->cra_flags = CRYPTO_ALG_ASYNC |
 381                           CRYPTO_ALG_KERN_DRIVER_ONLY |
 382                           CRYPTO_ALG_NEED_FALLBACK;
 383         base->cra_blocksize = AES_BLOCK_SIZE;
 384         base->cra_ctxsize = sizeof(struct ccp_ctx);
 385         base->cra_priority = CCP_CRA_PRIORITY;
 386         base->cra_init = ccp_aes_cmac_cra_init;
 387         base->cra_module = THIS_MODULE;
 388
 389         ret = crypto_register_ahash(alg);
 390         if (ret) {
 391                 pr_err("%s ahash algorithm registration error (%d)\n",
 392                        base->cra_name, ret);
 393                 kfree(ccp_alg);
 394                 return ret;
 395         }
 396
 397         list_add(&ccp_alg->entry, head);
 398
 399         return 0;
 400 }