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                 __u8 op)
 293 {
 294         struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(req);
 295         unsigned int ivsize = crypto_ablkcipher_ivsize(tfm);
 296         struct virtio_crypto_ablkcipher_ctx *ctx = vc_req->ablkcipher_ctx;
 297         struct virtio_crypto *vcrypto = ctx->vcrypto;
 298         struct virtio_crypto_op_data_req *req_data;
 299         int src_nents, dst_nents;
 300         int err;
 301         unsigned long flags;
 302         struct scatterlist outhdr, iv_sg, status_sg, **sgs;
 303         int i;
 304         u64 dst_len;
 305         unsigned int num_out = 0, num_in = 0;
 306         int sg_total;
 307         uint8_t *iv;
 308
 309         src_nents = sg_nents_for_len(req->src, req->nbytes);
 310         dst_nents = sg_nents(req->dst);
 311
 312         pr_debug("virtio_crypto: Number of sgs (src_nents: %d, dst_nents: %d)\n",
 313                         src_nents, dst_nents);
 314
 315         /* Why 3?  outhdr + iv + inhdr */
 316         sg_total = src_nents + dst_nents + 3;
 317         sgs = kzalloc_node(sg_total * sizeof(*sgs), GFP_ATOMIC,
 318                                 dev_to_node(&vcrypto->vdev->dev));
 319         if (!sgs)
 320                 return -ENOMEM;
 321
 322         req_data = kzalloc_node(sizeof(*req_data), GFP_ATOMIC,
 323                                 dev_to_node(&vcrypto->vdev->dev));
 324         if (!req_data) {
 325                 kfree(sgs);
 326                 return -ENOMEM;
 327         }
 328
 329         vc_req->req_data = req_data;
 330         vc_req->type = VIRTIO_CRYPTO_SYM_OP_CIPHER;
 331         /* Head of operation */
 332         if (op) {
 333                 req_data->header.session_id =
 334                         cpu_to_le64(ctx->enc_sess_info.session_id);
 335                 req_data->header.opcode =
 336                         cpu_to_le32(VIRTIO_CRYPTO_CIPHER_ENCRYPT);
 337         } else {
 338                 req_data->header.session_id =
 339                         cpu_to_le64(ctx->dec_sess_info.session_id);
 340             req_data->header.opcode =
 341                         cpu_to_le32(VIRTIO_CRYPTO_CIPHER_DECRYPT);
 342         }
 343         req_data->u.sym_req.op_type = cpu_to_le32(VIRTIO_CRYPTO_SYM_OP_CIPHER);
 344         req_data->u.sym_req.u.cipher.para.iv_len = cpu_to_le32(ivsize);
 345         req_data->u.sym_req.u.cipher.para.src_data_len =
 346                         cpu_to_le32(req->nbytes);
 347
 348         dst_len = virtio_crypto_alg_sg_nents_length(req->dst);
 349         if (unlikely(dst_len > U32_MAX)) {
 350                 pr_err("virtio_crypto: The dst_len is beyond U32_MAX\n");
 351                 err = -EINVAL;
 352                 goto free;
 353         }
 354
 355         pr_debug("virtio_crypto: src_len: %u, dst_len: %llu\n",
 356                         req->nbytes, dst_len);
 357
 358         if (unlikely(req->nbytes + dst_len + ivsize +
 359                 sizeof(vc_req->status) > vcrypto->max_size)) {
 360                 pr_err("virtio_crypto: The length is too big\n");
 361                 err = -EINVAL;
 362                 goto free;
 363         }
 364
 365         req_data->u.sym_req.u.cipher.para.dst_data_len =
 366                         cpu_to_le32((uint32_t)dst_len);
 367
 368         /* Outhdr */
 369         sg_init_one(&outhdr, req_data, sizeof(*req_data));
 370         sgs[num_out++] = &outhdr;
 371
 372         /* IV */
 373
 374         /*
 375          * Avoid to do DMA from the stack, switch to using
 376          * dynamically-allocated for the IV
 377          */
 378         iv = kzalloc_node(ivsize, GFP_ATOMIC,
 379                                 dev_to_node(&vcrypto->vdev->dev));
 380         if (!iv) {
 381                 err = -ENOMEM;
 382                 goto free;
 383         }
 384         memcpy(iv, req->info, ivsize);
 385         sg_init_one(&iv_sg, iv, ivsize);
 386         sgs[num_out++] = &iv_sg;
 387         vc_req->iv = iv;
 388
 389         /* Source data */
 390         for (i = 0; i < src_nents; i++)
 391                 sgs[num_out++] = &req->src[i];
 392
 393         /* Destination data */
 394         for (i = 0; i < dst_nents; i++)
 395                 sgs[num_out + num_in++] = &req->dst[i];
 396
 397         /* Status */
 398         sg_init_one(&status_sg, &vc_req->status, sizeof(vc_req->status));
 399         sgs[num_out + num_in++] = &status_sg;
 400
 401         vc_req->sgs = sgs;
 402
 403         spin_lock_irqsave(&data_vq->lock, flags);
 404         err = virtqueue_add_sgs(data_vq->vq, sgs, num_out,
 405                                 num_in, vc_req, GFP_ATOMIC);
 406         virtqueue_kick(data_vq->vq);
 407         spin_unlock_irqrestore(&data_vq->lock, flags);
 408         if (unlikely(err < 0))
 409                 goto free_iv;
 410
 411         return 0;
 412
 413 free_iv:
 414         kzfree(iv);
 415 free:
 416         kzfree(req_data);
 417         kfree(sgs);
 418         return err;
 419 }
 420
 421 static int virtio_crypto_ablkcipher_encrypt(struct ablkcipher_request *req)
 422 {
 423         struct crypto_ablkcipher *atfm = crypto_ablkcipher_reqtfm(req);
 424         struct virtio_crypto_ablkcipher_ctx *ctx = crypto_ablkcipher_ctx(atfm);
 425         struct virtio_crypto_request *vc_req = ablkcipher_request_ctx(req);
 426         struct virtio_crypto *vcrypto = ctx->vcrypto;
 427         int ret;
 428         /* Use the first data virtqueue as default */
 429         struct data_queue *data_vq = &vcrypto->data_vq[0];
 430
 431         vc_req->ablkcipher_ctx = ctx;
 432         vc_req->ablkcipher_req = req;
 433         ret = __virtio_crypto_ablkcipher_do_req(vc_req, req, data_vq, 1);
 434         if (ret < 0) {
 435                 pr_err("virtio_crypto: Encryption failed!\n");
 436                 return ret;
 437         }
 438
 439         return -EINPROGRESS;
 440 }
 441
 442 static int virtio_crypto_ablkcipher_decrypt(struct ablkcipher_request *req)
 443 {
 444         struct crypto_ablkcipher *atfm = crypto_ablkcipher_reqtfm(req);
 445         struct virtio_crypto_ablkcipher_ctx *ctx = crypto_ablkcipher_ctx(atfm);
 446         struct virtio_crypto_request *vc_req = ablkcipher_request_ctx(req);
 447         struct virtio_crypto *vcrypto = ctx->vcrypto;
 448         int ret;
 449         /* Use the first data virtqueue as default */
 450         struct data_queue *data_vq = &vcrypto->data_vq[0];
 451
 452         vc_req->ablkcipher_ctx = ctx;
 453         vc_req->ablkcipher_req = req;
 454
 455         ret = __virtio_crypto_ablkcipher_do_req(vc_req, req, data_vq, 0);
 456         if (ret < 0) {
 457                 pr_err("virtio_crypto: Decryption failed!\n");
 458                 return ret;
 459         }
 460
 461         return -EINPROGRESS;
 462 }
 463
 464 static int virtio_crypto_ablkcipher_init(struct crypto_tfm *tfm)
 465 {
 466         struct virtio_crypto_ablkcipher_ctx *ctx = crypto_tfm_ctx(tfm);
 467
 468         tfm->crt_ablkcipher.reqsize = sizeof(struct virtio_crypto_request);
 469         ctx->tfm = tfm;
 470
 471         return 0;
 472 }
 473
 474 static void virtio_crypto_ablkcipher_exit(struct crypto_tfm *tfm)
 475 {
 476         struct virtio_crypto_ablkcipher_ctx *ctx = crypto_tfm_ctx(tfm);
 477
 478         if (!ctx->vcrypto)
 479                 return;
 480
 481         virtio_crypto_alg_ablkcipher_close_session(ctx, 1);
 482         virtio_crypto_alg_ablkcipher_close_session(ctx, 0);
 483         virtcrypto_dev_put(ctx->vcrypto);
 484         ctx->vcrypto = NULL;
 485 }
 486
 487 static struct crypto_alg virtio_crypto_algs[] = { {
 488         .cra_name = "cbc(aes)",
 489         .cra_driver_name = "virtio_crypto_aes_cbc",
 490         .cra_priority = 501,
 491         .cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
 492         .cra_blocksize = AES_BLOCK_SIZE,
 493         .cra_ctxsize  = sizeof(struct virtio_crypto_ablkcipher_ctx),
 494         .cra_alignmask = 0,
 495         .cra_module = THIS_MODULE,
 496         .cra_type = &crypto_ablkcipher_type,
 497         .cra_init = virtio_crypto_ablkcipher_init,
 498         .cra_exit = virtio_crypto_ablkcipher_exit,
 499         .cra_u = {
 500            .ablkcipher = {
 501                         .setkey = virtio_crypto_ablkcipher_setkey,
 502                         .decrypt = virtio_crypto_ablkcipher_decrypt,
 503                         .encrypt = virtio_crypto_ablkcipher_encrypt,
 504                         .min_keysize = AES_MIN_KEY_SIZE,
 505                         .max_keysize = AES_MAX_KEY_SIZE,
 506                         .ivsize = AES_BLOCK_SIZE,
 507                 },
 508         },
 509 } };
 510
 511 int virtio_crypto_algs_register(void)
 512 {
 513         int ret = 0;
 514
 515         mutex_lock(&algs_lock);
 516         if (++virtio_crypto_active_devs != 1)
 517                 goto unlock;
 518
 519         ret = crypto_register_algs(virtio_crypto_algs,
 520                         ARRAY_SIZE(virtio_crypto_algs));
 521         if (ret)
 522                 virtio_crypto_active_devs--;
 523
 524 unlock:
 525         mutex_unlock(&algs_lock);
 526         return ret;
 527 }
 528
 529 void virtio_crypto_algs_unregister(void)
 530 {
 531         mutex_lock(&algs_lock);
 532         if (--virtio_crypto_active_devs != 0)
 533                 goto unlock;
 534
 535         crypto_unregister_algs(virtio_crypto_algs,
 536                         ARRAY_SIZE(virtio_crypto_algs));
 537
 538 unlock:
 539         mutex_unlock(&algs_lock);
 540 }