drivers/crypto/virtio/virtio_crypto_algs.c

   1  /* Algorithms supported by virtio crypto device
   2   *
   3   * Authors: Gonglei <arei.gonglei@huawei.com>
   4   *
   5   * Copyright 2016 HUAWEI TECHNOLOGIES CO., LTD.
   6   *
   7   * This program is free software; you can redistribute it and/or modify
   8   * it under the terms of the GNU General Public License as published by
   9   * the Free Software Foundation; either version 2 of the License, or
  10   * (at your option) any later version.
  11   *
  12   * This program is distributed in the hope that it will be useful,
  13   * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15   * GNU General Public License for more details.
  16   *
  17   * You should have received a copy of the GNU General Public License
  18   * along with this program; if not, see <http://www.gnu.org/licenses/>.
  19   */
  20
  21 #include <linux/scatterlist.h>
  22 #include <crypto/algapi.h>
  23 #include <linux/err.h>
  24 #include <crypto/scatterwalk.h>
  25 #include <linux/atomic.h>
  26
  27 #include <uapi/linux/virtio_crypto.h>
  28 #include "virtio_crypto_common.h"
  29
  30 /*
  31  * The algs_lock protects the below global virtio_crypto_active_devs
  32  * and crypto algorithms registion.
  33  */
  34 static DEFINE_MUTEX(algs_lock);
  35 static unsigned int virtio_crypto_active_devs;
  36
  37 static u64 virtio_crypto_alg_sg_nents_length(struct scatterlist *sg)
  38 {
  39         u64 total = 0;
  40
  41         for (total = 0; sg; sg = sg_next(sg))
  42                 total += sg->length;
  43
  44         return total;
  45 }
  46
  47 static int
  48 virtio_crypto_alg_validate_key(int key_len, uint32_t *alg)
  49 {
  50         switch (key_len) {
  51         case AES_KEYSIZE_128:
  52         case AES_KEYSIZE_192:
  53         case AES_KEYSIZE_256:
  54                 *alg = VIRTIO_CRYPTO_CIPHER_AES_CBC;
  55                 break;
  56         default:
  57                 pr_err("virtio_crypto: Unsupported key length: %d\n",
  58                         key_len);
  59                 return -EINVAL;
  60         }
  61         return 0;
  62 }
  63
  64 static int virtio_crypto_alg_ablkcipher_init_session(
  65                 struct virtio_crypto_ablkcipher_ctx *ctx,
  66                 uint32_t alg, const uint8_t *key,
  67                 unsigned int keylen,
  68                 int encrypt)
  69 {
  70         struct scatterlist outhdr, key_sg, inhdr, *sgs[3];
  71         unsigned int tmp;
  72         struct virtio_crypto *vcrypto = ctx->vcrypto;
  73         int op = encrypt ? VIRTIO_CRYPTO_OP_ENCRYPT : VIRTIO_CRYPTO_OP_DECRYPT;
  74         int err;
  75         unsigned int num_out = 0, num_in = 0;
  76
  77         /*
  78          * Avoid to do DMA from the stack, switch to using
  79          * dynamically-allocated for the key
  80          */
  81         uint8_t *cipher_key = kmalloc(keylen, GFP_ATOMIC);
  82
  83         if (!cipher_key)
  84                 return -ENOMEM;
  85
  86         memcpy(cipher_key, key, keylen);
  87
  88         spin_lock(&vcrypto->ctrl_lock);
  89         /* Pad ctrl header */
  90         vcrypto->ctrl.header.opcode =
  91                 cpu_to_le32(VIRTIO_CRYPTO_CIPHER_CREATE_SESSION);
  92         vcrypto->ctrl.header.algo = cpu_to_le32(alg);
  93         /* Set the default dataqueue id to 0 */
  94         vcrypto->ctrl.header.queue_id = 0;
  95
  96         vcrypto->input.status = cpu_to_le32(VIRTIO_CRYPTO_ERR);
  97         /* Pad cipher's parameters */
  98         vcrypto->ctrl.u.sym_create_session.op_type =
  99                 cpu_to_le32(VIRTIO_CRYPTO_SYM_OP_CIPHER);
 100         vcrypto->ctrl.u.sym_create_session.u.cipher.para.algo =
 101                 vcrypto->ctrl.header.algo;
 102         vcrypto->ctrl.u.sym_create_session.u.cipher.para.keylen =
 103                 cpu_to_le32(keylen);
 104         vcrypto->ctrl.u.sym_create_session.u.cipher.para.op =
 105                 cpu_to_le32(op);
 106
 107         sg_init_one(&outhdr, &vcrypto->ctrl, sizeof(vcrypto->ctrl));
 108         sgs[num_out++] = &outhdr;
 109
 110         /* Set key */
 111         sg_init_one(&key_sg, cipher_key, keylen);
 112         sgs[num_out++] = &key_sg;
 113
 114         /* Return status and session id back */
 115         sg_init_one(&inhdr, &vcrypto->input, sizeof(vcrypto->input));
 116         sgs[num_out + num_in++] = &inhdr;
 117
 118         err = virtqueue_add_sgs(vcrypto->ctrl_vq, sgs, num_out,
 119                                 num_in, vcrypto, GFP_ATOMIC);
 120         if (err < 0) {
 121                 spin_unlock(&vcrypto->ctrl_lock);
 122                 kzfree(cipher_key);
 123                 return err;
 124         }
 125         virtqueue_kick(vcrypto->ctrl_vq);
 126
 127         /*
 128          * Trapping into the hypervisor, so the request should be
 129          * handled immediately.
 130          */
 131         while (!virtqueue_get_buf(vcrypto->ctrl_vq, &tmp) &&
 132                !virtqueue_is_broken(vcrypto->ctrl_vq))
 133                 cpu_relax();
 134
 135         if (le32_to_cpu(vcrypto->input.status) != VIRTIO_CRYPTO_OK) {
 136                 spin_unlock(&vcrypto->ctrl_lock);
 137                 pr_err("virtio_crypto: Create session failed status: %u\n",
 138                         le32_to_cpu(vcrypto->input.status));
 139                 kzfree(cipher_key);
 140                 return -EINVAL;
 141         }
 142
 143         if (encrypt)
 144                 ctx->enc_sess_info.session_id =
 145                         le64_to_cpu(vcrypto->input.session_id);
 146         else
 147                 ctx->dec_sess_info.session_id =
 148                         le64_to_cpu(vcrypto->input.session_id);
 149
 150         spin_unlock(&vcrypto->ctrl_lock);
 151
 152         kzfree(cipher_key);
 153         return 0;
 154 }
 155
 156 static int virtio_crypto_alg_ablkcipher_close_session(
 157                 struct virtio_crypto_ablkcipher_ctx *ctx,
 158                 int encrypt)
 159 {
 160         struct scatterlist outhdr, status_sg, *sgs[2];
 161         unsigned int tmp;
 162         struct virtio_crypto_destroy_session_req *destroy_session;
 163         struct virtio_crypto *vcrypto = ctx->vcrypto;
 164         int err;
 165         unsigned int num_out = 0, num_in = 0;
 166
 167         spin_lock(&vcrypto->ctrl_lock);
 168         vcrypto->ctrl_status.status = VIRTIO_CRYPTO_ERR;
 169         /* Pad ctrl header */
 170         vcrypto->ctrl.header.opcode =
 171                 cpu_to_le32(VIRTIO_CRYPTO_CIPHER_DESTROY_SESSION);
 172         /* Set the default virtqueue id to 0 */
 173         vcrypto->ctrl.header.queue_id = 0;
 174
 175         destroy_session = &vcrypto->ctrl.u.destroy_session;
 176
 177         if (encrypt)
 178                 destroy_session->session_id =
 179                         cpu_to_le64(ctx->enc_sess_info.session_id);
 180         else
 181                 destroy_session->session_id =
 182                         cpu_to_le64(ctx->dec_sess_info.session_id);
 183
 184         sg_init_one(&outhdr, &vcrypto->ctrl, sizeof(vcrypto->ctrl));
 185         sgs[num_out++] = &outhdr;
 186
 187         /* Return status and session id back */
 188         sg_init_one(&status_sg, &vcrypto->ctrl_status.status,
 189                 sizeof(vcrypto->ctrl_status.status));
 190         sgs[num_out + num_in++] = &status_sg;
 191
 192         err = virtqueue_add_sgs(vcrypto->ctrl_vq, sgs, num_out,
 193                         num_in, vcrypto, GFP_ATOMIC);
 194         if (err < 0) {
 195                 spin_unlock(&vcrypto->ctrl_lock);
 196                 return err;
 197         }
 198         virtqueue_kick(vcrypto->ctrl_vq);
 199
 200         while (!virtqueue_get_buf(vcrypto->ctrl_vq, &tmp) &&
 201                !virtqueue_is_broken(vcrypto->ctrl_vq))
 202                 cpu_relax();
 203
 204         if (vcrypto->ctrl_status.status != VIRTIO_CRYPTO_OK) {
 205                 spin_unlock(&vcrypto->ctrl_lock);
 206                 pr_err("virtio_crypto: Close session failed status: %u, session_id: 0x%llx\n",
 207                         vcrypto->ctrl_status.status,
 208                         destroy_session->session_id);
 209
 210                 return -EINVAL;
 211         }
 212         spin_unlock(&vcrypto->ctrl_lock);
 213
 214         return 0;
 215 }
 216
 217 static int virtio_crypto_alg_ablkcipher_init_sessions(
 218                 struct virtio_crypto_ablkcipher_ctx *ctx,
 219                 const uint8_t *key, unsigned int keylen)
 220 {
 221         uint32_t alg;
 222         int ret;
 223         struct virtio_crypto *vcrypto = ctx->vcrypto;
 224
 225         if (keylen > vcrypto->max_cipher_key_len) {
 226                 pr_err("virtio_crypto: the key is too long\n");
 227                 goto bad_key;
 228         }
 229
 230         if (virtio_crypto_alg_validate_key(keylen, &alg))
 231                 goto bad_key;
 232
 233         /* Create encryption session */
 234         ret = virtio_crypto_alg_ablkcipher_init_session(ctx,
 235                         alg, key, keylen, 1);
 236         if (ret)
 237                 return ret;
 238         /* Create decryption session */
 239         ret = virtio_crypto_alg_ablkcipher_init_session(ctx,
 240                         alg, key, keylen, 0);
 241         if (ret) {
 242                 virtio_crypto_alg_ablkcipher_close_session(ctx, 1);
 243                 return ret;
 244         }
 245         return 0;
 246
 247 bad_key:
 248         crypto_tfm_set_flags(ctx->tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
 249         return -EINVAL;
 250 }
 251
 252 /* Note: kernel crypto API realization */
 253 static int virtio_crypto_ablkcipher_setkey(struct crypto_ablkcipher *tfm,
 254                                          const uint8_t *key,
 255                                          unsigned int keylen)
 256 {
 257         struct virtio_crypto_ablkcipher_ctx *ctx = crypto_ablkcipher_ctx(tfm);
 258         int ret;
 259
 260         if (!ctx->vcrypto) {
 261                 /* New key */
 262                 int node = virtio_crypto_get_current_node();
 263                 struct virtio_crypto *vcrypto =
 264                                       virtcrypto_get_dev_node(node);
 265                 if (!vcrypto) {
 266                         pr_err("virtio_crypto: Could not find a virtio device in the system");
 267                         return -ENODEV;
 268                 }
 269
 270                 ctx->vcrypto = vcrypto;
 271         } else {
 272                 /* Rekeying, we should close the created sessions previously */
 273                 virtio_crypto_alg_ablkcipher_close_session(ctx, 1);
 274                 virtio_crypto_alg_ablkcipher_close_session(ctx, 0);
 275         }
 276
 277         ret = virtio_crypto_alg_ablkcipher_init_sessions(ctx, key, keylen);
 278         if (ret) {
 279                 virtcrypto_dev_put(ctx->vcrypto);
 280                 ctx->vcrypto = NULL;
 281
 282                 return ret;
 283         }
 284
 285         return 0;
 286 }
 287
 288 static int
 289 __virtio_crypto_ablkcipher_do_req(struct virtio_crypto_request *vc_req,
 290                 struct ablkcipher_request *req,
 291                 struct data_queue *data_vq)
 292 {
 293         struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(req);
 294         unsigned int ivsize = crypto_ablkcipher_ivsize(tfm);
 295         struct virtio_crypto_ablkcipher_ctx *ctx = vc_req->ablkcipher_ctx;
 296         struct virtio_crypto *vcrypto = ctx->vcrypto;
 297         struct virtio_crypto_op_data_req *req_data;
 298         int src_nents, dst_nents;
 299         int err;
 300         unsigned long flags;
 301         struct scatterlist outhdr, iv_sg, status_sg, **sgs;
 302         int i;
 303         u64 dst_len;
 304         unsigned int num_out = 0, num_in = 0;
 305         int sg_total;
 306         uint8_t *iv;
 307
 308         src_nents = sg_nents_for_len(req->src, req->nbytes);
 309         dst_nents = sg_nents(req->dst);
 310
 311         pr_debug("virtio_crypto: Number of sgs (src_nents: %d, dst_nents: %d)\n",
 312                         src_nents, dst_nents);
 313
 314         /* Why 3?  outhdr + iv + inhdr */
 315         sg_total = src_nents + dst_nents + 3;
 316         sgs = kzalloc_node(sg_total * sizeof(*sgs), GFP_ATOMIC,
 317                                 dev_to_node(&vcrypto->vdev->dev));
 318         if (!sgs)
 319                 return -ENOMEM;
 320
 321         req_data = kzalloc_node(sizeof(*req_data), GFP_ATOMIC,
 322                                 dev_to_node(&vcrypto->vdev->dev));
 323         if (!req_data) {
 324                 kfree(sgs);
 325                 return -ENOMEM;
 326         }
 327
 328         vc_req->req_data = req_data;
 329         vc_req->type = VIRTIO_CRYPTO_SYM_OP_CIPHER;
 330         /* Head of operation */
 331         if (vc_req->encrypt) {
 332                 req_data->header.session_id =
 333                         cpu_to_le64(ctx->enc_sess_info.session_id);
 334                 req_data->header.opcode =
 335                         cpu_to_le32(VIRTIO_CRYPTO_CIPHER_ENCRYPT);
 336         } else {
 337                 req_data->header.session_id =
 338                         cpu_to_le64(ctx->dec_sess_info.session_id);
 339             req_data->header.opcode =
 340                         cpu_to_le32(VIRTIO_CRYPTO_CIPHER_DECRYPT);
 341         }
 342         req_data->u.sym_req.op_type = cpu_to_le32(VIRTIO_CRYPTO_SYM_OP_CIPHER);
 343         req_data->u.sym_req.u.cipher.para.iv_len = cpu_to_le32(ivsize);
 344         req_data->u.sym_req.u.cipher.para.src_data_len =
 345                         cpu_to_le32(req->nbytes);
 346
 347         dst_len = virtio_crypto_alg_sg_nents_length(req->dst);
 348         if (unlikely(dst_len > U32_MAX)) {
 349                 pr_err("virtio_crypto: The dst_len is beyond U32_MAX\n");
 350                 err = -EINVAL;
 351                 goto free;
 352         }
 353
 354         pr_debug("virtio_crypto: src_len: %u, dst_len: %llu\n",
 355                         req->nbytes, dst_len);
 356
 357         if (unlikely(req->nbytes + dst_len + ivsize +
 358                 sizeof(vc_req->status) > vcrypto->max_size)) {
 359                 pr_err("virtio_crypto: The length is too big\n");
 360                 err = -EINVAL;
 361                 goto free;
 362         }
 363
 364         req_data->u.sym_req.u.cipher.para.dst_data_len =
 365                         cpu_to_le32((uint32_t)dst_len);
 366
 367         /* Outhdr */
 368         sg_init_one(&outhdr, req_data, sizeof(*req_data));
 369         sgs[num_out++] = &outhdr;
 370
 371         /* IV */
 372
 373         /*
 374          * Avoid to do DMA from the stack, switch to using
 375          * dynamically-allocated for the IV
 376          */
 377         iv = kzalloc_node(ivsize, GFP_ATOMIC,
 378                                 dev_to_node(&vcrypto->vdev->dev));
 379         if (!iv) {
 380                 err = -ENOMEM;
 381                 goto free;
 382         }
 383         memcpy(iv, req->info, ivsize);
 384         sg_init_one(&iv_sg, iv, ivsize);
 385         sgs[num_out++] = &iv_sg;
 386         vc_req->iv = iv;
 387
 388         /* Source data */
 389         for (i = 0; i < src_nents; i++)
 390                 sgs[num_out++] = &req->src[i];
 391
 392         /* Destination data */
 393         for (i = 0; i < dst_nents; i++)
 394                 sgs[num_out + num_in++] = &req->dst[i];
 395
 396         /* Status */
 397         sg_init_one(&status_sg, &vc_req->status, sizeof(vc_req->status));
 398         sgs[num_out + num_in++] = &status_sg;
 399
 400         vc_req->sgs = sgs;
 401
 402         spin_lock_irqsave(&data_vq->lock, flags);
 403         err = virtqueue_add_sgs(data_vq->vq, sgs, num_out,
 404                                 num_in, vc_req, GFP_ATOMIC);
 405         virtqueue_kick(data_vq->vq);
 406         spin_unlock_irqrestore(&data_vq->lock, flags);
 407         if (unlikely(err < 0))
 408                 goto free_iv;
 409
 410         return 0;
 411
 412 free_iv:
 413         kzfree(iv);
 414 free:
 415         kzfree(req_data);
 416         kfree(sgs);
 417         return err;
 418 }
 419
 420 static int virtio_crypto_ablkcipher_encrypt(struct ablkcipher_request *req)
 421 {
 422         struct crypto_ablkcipher *atfm = crypto_ablkcipher_reqtfm(req);
 423         struct virtio_crypto_ablkcipher_ctx *ctx = crypto_ablkcipher_ctx(atfm);
 424         struct virtio_crypto_request *vc_req = ablkcipher_request_ctx(req);
 425         struct virtio_crypto *vcrypto = ctx->vcrypto;
 426         /* Use the first data virtqueue as default */
 427         struct data_queue *data_vq = &vcrypto->data_vq[0];
 428
 429         vc_req->ablkcipher_ctx = ctx;
 430         vc_req->ablkcipher_req = req;
 431         vc_req->encrypt = true;
 432         vc_req->dataq = data_vq;
 433
 434         return crypto_transfer_cipher_request_to_engine(data_vq->engine, req);
 435 }
 436
 437 static int virtio_crypto_ablkcipher_decrypt(struct ablkcipher_request *req)
 438 {
 439         struct crypto_ablkcipher *atfm = crypto_ablkcipher_reqtfm(req);
 440         struct virtio_crypto_ablkcipher_ctx *ctx = crypto_ablkcipher_ctx(atfm);
 441         struct virtio_crypto_request *vc_req = ablkcipher_request_ctx(req);
 442         struct virtio_crypto *vcrypto = ctx->vcrypto;
 443         /* Use the first data virtqueue as default */
 444         struct data_queue *data_vq = &vcrypto->data_vq[0];
 445
 446         vc_req->ablkcipher_ctx = ctx;
 447         vc_req->ablkcipher_req = req;
 448
 449         vc_req->encrypt = false;
 450         vc_req->dataq = data_vq;
 451
 452         return crypto_transfer_cipher_request_to_engine(data_vq->engine, req);
 453 }
 454
 455 static int virtio_crypto_ablkcipher_init(struct crypto_tfm *tfm)
 456 {
 457         struct virtio_crypto_ablkcipher_ctx *ctx = crypto_tfm_ctx(tfm);
 458
 459         tfm->crt_ablkcipher.reqsize = sizeof(struct virtio_crypto_request);
 460         ctx->tfm = tfm;
 461
 462         return 0;
 463 }
 464
 465 static void virtio_crypto_ablkcipher_exit(struct crypto_tfm *tfm)
 466 {
 467         struct virtio_crypto_ablkcipher_ctx *ctx = crypto_tfm_ctx(tfm);
 468
 469         if (!ctx->vcrypto)
 470                 return;
 471
 472         virtio_crypto_alg_ablkcipher_close_session(ctx, 1);
 473         virtio_crypto_alg_ablkcipher_close_session(ctx, 0);
 474         virtcrypto_dev_put(ctx->vcrypto);
 475         ctx->vcrypto = NULL;
 476 }
 477
 478 int virtio_crypto_ablkcipher_crypt_req(
 479         struct crypto_engine *engine,
 480         struct ablkcipher_request *req)
 481 {
 482         struct virtio_crypto_request *vc_req = ablkcipher_request_ctx(req);
 483         struct data_queue *data_vq = vc_req->dataq;
 484         int ret;
 485
 486         ret = __virtio_crypto_ablkcipher_do_req(vc_req, req, data_vq);
 487         if (ret < 0)
 488                 return ret;
 489
 490         virtqueue_kick(data_vq->vq);
 491
 492         return 0;
 493 }
 494
 495 void virtio_crypto_ablkcipher_finalize_req(
 496         struct virtio_crypto_request *vc_req,
 497         struct ablkcipher_request *req,
 498         int err)
 499 {
 500         crypto_finalize_cipher_request(vc_req->dataq->engine, req, err);
 501
 502         virtcrypto_clear_request(vc_req);
 503 }
 504
 505 static struct crypto_alg virtio_crypto_algs[] = { {
 506         .cra_name = "cbc(aes)",
 507         .cra_driver_name = "virtio_crypto_aes_cbc",
 508         .cra_priority = 150,
 509         .cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
 510         .cra_blocksize = AES_BLOCK_SIZE,
 511         .cra_ctxsize  = sizeof(struct virtio_crypto_ablkcipher_ctx),
 512         .cra_alignmask = 0,
 513         .cra_module = THIS_MODULE,
 514         .cra_type = &crypto_ablkcipher_type,
 515         .cra_init = virtio_crypto_ablkcipher_init,
 516         .cra_exit = virtio_crypto_ablkcipher_exit,
 517         .cra_u = {
 518            .ablkcipher = {
 519                         .setkey = virtio_crypto_ablkcipher_setkey,
 520                         .decrypt = virtio_crypto_ablkcipher_decrypt,
 521                         .encrypt = virtio_crypto_ablkcipher_encrypt,
 522                         .min_keysize = AES_MIN_KEY_SIZE,
 523                         .max_keysize = AES_MAX_KEY_SIZE,
 524                         .ivsize = AES_BLOCK_SIZE,
 525                 },
 526         },
 527 } };
 528
 529 int virtio_crypto_algs_register(void)
 530 {
 531         int ret = 0;
 532
 533         mutex_lock(&algs_lock);
 534         if (++virtio_crypto_active_devs != 1)
 535                 goto unlock;
 536
 537         ret = crypto_register_algs(virtio_crypto_algs,
 538                         ARRAY_SIZE(virtio_crypto_algs));
 539         if (ret)
 540                 virtio_crypto_active_devs--;
 541
 542 unlock:
 543         mutex_unlock(&algs_lock);
 544         return ret;
 545 }
 546
 547 void virtio_crypto_algs_unregister(void)
 548 {
 549         mutex_lock(&algs_lock);
 550         if (--virtio_crypto_active_devs != 0)
 551                 goto unlock;
 552
 553         crypto_unregister_algs(virtio_crypto_algs,
 554                         ARRAY_SIZE(virtio_crypto_algs));
 555
 556 unlock:
 557         mutex_unlock(&algs_lock);
 558 }