crypto/rsa-pkcs1pad.c

   1 /*
   2  * RSA padding templates.
   3  *
   4  * Copyright (c) 2015  Intel Corporation
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the Free
   8  * Software Foundation; either version 2 of the License, or (at your option)
   9  * any later version.
  10  */
  11
  12 #include <crypto/algapi.h>
  13 #include <crypto/akcipher.h>
  14 #include <crypto/internal/akcipher.h>
  15 #include <linux/err.h>
  16 #include <linux/init.h>
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/random.h>
  20
  21 /*
  22  * Hash algorithm OIDs plus ASN.1 DER wrappings [RFC4880 sec 5.2.2].
  23  */
  24 static const u8 rsa_digest_info_md5[] = {
  25         0x30, 0x20, 0x30, 0x0c, 0x06, 0x08,
  26         0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x02, 0x05, /* OID */
  27         0x05, 0x00, 0x04, 0x10
  28 };
  29
  30 static const u8 rsa_digest_info_sha1[] = {
  31         0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
  32         0x2b, 0x0e, 0x03, 0x02, 0x1a,
  33         0x05, 0x00, 0x04, 0x14
  34 };
  35
  36 static const u8 rsa_digest_info_rmd160[] = {
  37         0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
  38         0x2b, 0x24, 0x03, 0x02, 0x01,
  39         0x05, 0x00, 0x04, 0x14
  40 };
  41
  42 static const u8 rsa_digest_info_sha224[] = {
  43         0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09,
  44         0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04,
  45         0x05, 0x00, 0x04, 0x1c
  46 };
  47
  48 static const u8 rsa_digest_info_sha256[] = {
  49         0x30, 0x31, 0x30, 0x0d, 0x06, 0x09,
  50         0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01,
  51         0x05, 0x00, 0x04, 0x20
  52 };
  53
  54 static const u8 rsa_digest_info_sha384[] = {
  55         0x30, 0x41, 0x30, 0x0d, 0x06, 0x09,
  56         0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02,
  57         0x05, 0x00, 0x04, 0x30
  58 };
  59
  60 static const u8 rsa_digest_info_sha512[] = {
  61         0x30, 0x51, 0x30, 0x0d, 0x06, 0x09,
  62         0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03,
  63         0x05, 0x00, 0x04, 0x40
  64 };
  65
  66 static const struct rsa_asn1_template {
  67         const char      *name;
  68         const u8        *data;
  69         size_t          size;
  70 } rsa_asn1_templates[] = {
  71 #define _(X) { #X, rsa_digest_info_##X, sizeof(rsa_digest_info_##X) }
  72         _(md5),
  73         _(sha1),
  74         _(rmd160),
  75         _(sha256),
  76         _(sha384),
  77         _(sha512),
  78         _(sha224),
  79         { NULL }
  80 #undef _
  81 };
  82
  83 static const struct rsa_asn1_template *rsa_lookup_asn1(const char *name)
  84 {
  85         const struct rsa_asn1_template *p;
  86
  87         for (p = rsa_asn1_templates; p->name; p++)
  88                 if (strcmp(name, p->name) == 0)
  89                         return p;
  90         return NULL;
  91 }
  92
  93 struct pkcs1pad_ctx {
  94         struct crypto_akcipher *child;
  95         unsigned int key_size;
  96 };
  97
  98 struct pkcs1pad_inst_ctx {
  99         struct crypto_akcipher_spawn spawn;
 100         const struct rsa_asn1_template *digest_info;
 101 };
 102
 103 struct pkcs1pad_request {
 104         struct scatterlist in_sg[2], out_sg[1];
 105         uint8_t *in_buf, *out_buf;
 106         struct akcipher_request child_req;
 107 };
 108
 109 static int pkcs1pad_set_pub_key(struct crypto_akcipher *tfm, const void *key,
 110                 unsigned int keylen)
 111 {
 112         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 113         int err;
 114
 115         ctx->key_size = 0;
 116
 117         err = crypto_akcipher_set_pub_key(ctx->child, key, keylen);
 118         if (err)
 119                 return err;
 120
 121         /* Find out new modulus size from rsa implementation */
 122         err = crypto_akcipher_maxsize(ctx->child);
 123         if (err < 0)
 124                 return err;
 125
 126         if (err > PAGE_SIZE)
 127                 return -ENOTSUPP;
 128
 129         ctx->key_size = err;
 130         return 0;
 131 }
 132
 133 static int pkcs1pad_set_priv_key(struct crypto_akcipher *tfm, const void *key,
 134                 unsigned int keylen)
 135 {
 136         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 137         int err;
 138
 139         ctx->key_size = 0;
 140
 141         err = crypto_akcipher_set_priv_key(ctx->child, key, keylen);
 142         if (err)
 143                 return err;
 144
 145         /* Find out new modulus size from rsa implementation */
 146         err = crypto_akcipher_maxsize(ctx->child);
 147         if (err < 0)
 148                 return err;
 149
 150         if (err > PAGE_SIZE)
 151                 return -ENOTSUPP;
 152
 153         ctx->key_size = err;
 154         return 0;
 155 }
 156
 157 static int pkcs1pad_get_max_size(struct crypto_akcipher *tfm)
 158 {
 159         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 160
 161         /*
 162          * The maximum destination buffer size for the encrypt/sign operations
 163          * will be the same as for RSA, even though it's smaller for
 164          * decrypt/verify.
 165          */
 166
 167         return ctx->key_size ?: -EINVAL;
 168 }
 169
 170 static void pkcs1pad_sg_set_buf(struct scatterlist *sg, void *buf, size_t len,
 171                 struct scatterlist *next)
 172 {
 173         int nsegs = next ? 2 : 1;
 174
 175         sg_init_table(sg, nsegs);
 176         sg_set_buf(sg, buf, len);
 177
 178         if (next)
 179                 sg_chain(sg, nsegs, next);
 180 }
 181
 182 static int pkcs1pad_encrypt_sign_complete(struct akcipher_request *req, int err)
 183 {
 184         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 185         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 186         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 187         unsigned int pad_len;
 188         unsigned int len;
 189         u8 *out_buf;
 190
 191         if (err)
 192                 goto out;
 193
 194         len = req_ctx->child_req.dst_len;
 195         pad_len = ctx->key_size - len;
 196
 197         /* Four billion to one */
 198         if (likely(!pad_len))
 199                 goto out;
 200
 201         out_buf = kzalloc(ctx->key_size, GFP_ATOMIC);
 202         err = -ENOMEM;
 203         if (!out_buf)
 204                 goto out;
 205
 206         sg_copy_to_buffer(req->dst, sg_nents_for_len(req->dst, len),
 207                           out_buf + pad_len, len);
 208         sg_copy_from_buffer(req->dst,
 209                             sg_nents_for_len(req->dst, ctx->key_size),
 210                             out_buf, ctx->key_size);
 211         kzfree(out_buf);
 212
 213 out:
 214         req->dst_len = ctx->key_size;
 215
 216         kfree(req_ctx->in_buf);
 217
 218         return err;
 219 }
 220
 221 static void pkcs1pad_encrypt_sign_complete_cb(
 222                 struct crypto_async_request *child_async_req, int err)
 223 {
 224         struct akcipher_request *req = child_async_req->data;
 225         struct crypto_async_request async_req;
 226
 227         if (err == -EINPROGRESS)
 228                 return;
 229
 230         async_req.data = req->base.data;
 231         async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
 232         async_req.flags = child_async_req->flags;
 233         req->base.complete(&async_req,
 234                         pkcs1pad_encrypt_sign_complete(req, err));
 235 }
 236
 237 static int pkcs1pad_encrypt(struct akcipher_request *req)
 238 {
 239         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 240         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 241         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 242         int err;
 243         unsigned int i, ps_end;
 244
 245         if (!ctx->key_size)
 246                 return -EINVAL;
 247
 248         if (req->src_len > ctx->key_size - 11)
 249                 return -EOVERFLOW;
 250
 251         if (req->dst_len < ctx->key_size) {
 252                 req->dst_len = ctx->key_size;
 253                 return -EOVERFLOW;
 254         }
 255
 256         req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
 257                                   GFP_KERNEL);
 258         if (!req_ctx->in_buf)
 259                 return -ENOMEM;
 260
 261         ps_end = ctx->key_size - req->src_len - 2;
 262         req_ctx->in_buf[0] = 0x02;
 263         for (i = 1; i < ps_end; i++)
 264                 req_ctx->in_buf[i] = 1 + prandom_u32_max(255);
 265         req_ctx->in_buf[ps_end] = 0x00;
 266
 267         pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
 268                         ctx->key_size - 1 - req->src_len, req->src);
 269
 270         req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
 271         if (!req_ctx->out_buf) {
 272                 kfree(req_ctx->in_buf);
 273                 return -ENOMEM;
 274         }
 275
 276         pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
 277                         ctx->key_size, NULL);
 278
 279         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 280         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 281                         pkcs1pad_encrypt_sign_complete_cb, req);
 282
 283         /* Reuse output buffer */
 284         akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
 285                                    req->dst, ctx->key_size - 1, req->dst_len);
 286
 287         err = crypto_akcipher_encrypt(&req_ctx->child_req);
 288         if (err != -EINPROGRESS &&
 289                         (err != -EBUSY ||
 290                          !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
 291                 return pkcs1pad_encrypt_sign_complete(req, err);
 292
 293         return err;
 294 }
 295
 296 static int pkcs1pad_decrypt_complete(struct akcipher_request *req, int err)
 297 {
 298         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 299         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 300         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 301         unsigned int pos;
 302
 303         if (err == -EOVERFLOW)
 304                 /* Decrypted value had no leading 0 byte */
 305                 err = -EINVAL;
 306
 307         if (err)
 308                 goto done;
 309
 310         if (req_ctx->child_req.dst_len != ctx->key_size - 1) {
 311                 err = -EINVAL;
 312                 goto done;
 313         }
 314
 315         if (req_ctx->out_buf[0] != 0x02) {
 316                 err = -EINVAL;
 317                 goto done;
 318         }
 319         for (pos = 1; pos < req_ctx->child_req.dst_len; pos++)
 320                 if (req_ctx->out_buf[pos] == 0x00)
 321                         break;
 322         if (pos < 9 || pos == req_ctx->child_req.dst_len) {
 323                 err = -EINVAL;
 324                 goto done;
 325         }
 326         pos++;
 327
 328         if (req->dst_len < req_ctx->child_req.dst_len - pos)
 329                 err = -EOVERFLOW;
 330         req->dst_len = req_ctx->child_req.dst_len - pos;
 331
 332         if (!err)
 333                 sg_copy_from_buffer(req->dst,
 334                                 sg_nents_for_len(req->dst, req->dst_len),
 335                                 req_ctx->out_buf + pos, req->dst_len);
 336
 337 done:
 338         kzfree(req_ctx->out_buf);
 339
 340         return err;
 341 }
 342
 343 static void pkcs1pad_decrypt_complete_cb(
 344                 struct crypto_async_request *child_async_req, int err)
 345 {
 346         struct akcipher_request *req = child_async_req->data;
 347         struct crypto_async_request async_req;
 348
 349         if (err == -EINPROGRESS)
 350                 return;
 351
 352         async_req.data = req->base.data;
 353         async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
 354         async_req.flags = child_async_req->flags;
 355         req->base.complete(&async_req, pkcs1pad_decrypt_complete(req, err));
 356 }
 357
 358 static int pkcs1pad_decrypt(struct akcipher_request *req)
 359 {
 360         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 361         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 362         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 363         int err;
 364
 365         if (!ctx->key_size || req->src_len != ctx->key_size)
 366                 return -EINVAL;
 367
 368         req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
 369         if (!req_ctx->out_buf)
 370                 return -ENOMEM;
 371
 372         pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
 373                             ctx->key_size, NULL);
 374
 375         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 376         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 377                         pkcs1pad_decrypt_complete_cb, req);
 378
 379         /* Reuse input buffer, output to a new buffer */
 380         akcipher_request_set_crypt(&req_ctx->child_req, req->src,
 381                                    req_ctx->out_sg, req->src_len,
 382                                    ctx->key_size);
 383
 384         err = crypto_akcipher_decrypt(&req_ctx->child_req);
 385         if (err != -EINPROGRESS &&
 386                         (err != -EBUSY ||
 387                          !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
 388                 return pkcs1pad_decrypt_complete(req, err);
 389
 390         return err;
 391 }
 392
 393 static int pkcs1pad_sign(struct akcipher_request *req)
 394 {
 395         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 396         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 397         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 398         struct akcipher_instance *inst = akcipher_alg_instance(tfm);
 399         struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
 400         const struct rsa_asn1_template *digest_info = ictx->digest_info;
 401         int err;
 402         unsigned int ps_end, digest_size = 0;
 403
 404         if (!ctx->key_size)
 405                 return -EINVAL;
 406
 407         digest_size = digest_info->size;
 408
 409         if (req->src_len + digest_size > ctx->key_size - 11)
 410                 return -EOVERFLOW;
 411
 412         if (req->dst_len < ctx->key_size) {
 413                 req->dst_len = ctx->key_size;
 414                 return -EOVERFLOW;
 415         }
 416
 417         req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
 418                                   GFP_KERNEL);
 419         if (!req_ctx->in_buf)
 420                 return -ENOMEM;
 421
 422         ps_end = ctx->key_size - digest_size - req->src_len - 2;
 423         req_ctx->in_buf[0] = 0x01;
 424         memset(req_ctx->in_buf + 1, 0xff, ps_end - 1);
 425         req_ctx->in_buf[ps_end] = 0x00;
 426
 427         memcpy(req_ctx->in_buf + ps_end + 1, digest_info->data,
 428                digest_info->size);
 429
 430         pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
 431                         ctx->key_size - 1 - req->src_len, req->src);
 432
 433         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 434         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 435                         pkcs1pad_encrypt_sign_complete_cb, req);
 436
 437         /* Reuse output buffer */
 438         akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
 439                                    req->dst, ctx->key_size - 1, req->dst_len);
 440
 441         err = crypto_akcipher_sign(&req_ctx->child_req);
 442         if (err != -EINPROGRESS &&
 443                         (err != -EBUSY ||
 444                          !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
 445                 return pkcs1pad_encrypt_sign_complete(req, err);
 446
 447         return err;
 448 }
 449
 450 static int pkcs1pad_verify_complete(struct akcipher_request *req, int err)
 451 {
 452         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 453         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 454         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 455         struct akcipher_instance *inst = akcipher_alg_instance(tfm);
 456         struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
 457         const struct rsa_asn1_template *digest_info = ictx->digest_info;
 458         unsigned int dst_len;
 459         unsigned int pos;
 460         u8 *out_buf;
 461
 462         if (err)
 463                 goto done;
 464
 465         err = -EINVAL;
 466         dst_len = req_ctx->child_req.dst_len;
 467         if (dst_len < ctx->key_size - 1)
 468                 goto done;
 469
 470         out_buf = req_ctx->out_buf;
 471         if (dst_len == ctx->key_size) {
 472                 if (out_buf[0] != 0x00)
 473                         /* Decrypted value had no leading 0 byte */
 474                         goto done;
 475
 476                 dst_len--;
 477                 out_buf++;
 478         }
 479
 480         err = -EBADMSG;
 481         if (out_buf[0] != 0x01)
 482                 goto done;
 483
 484         for (pos = 1; pos < dst_len; pos++)
 485                 if (out_buf[pos] != 0xff)
 486                         break;
 487
 488         if (pos < 9 || pos == dst_len || out_buf[pos] != 0x00)
 489                 goto done;
 490         pos++;
 491
 492         if (memcmp(out_buf + pos, digest_info->data, digest_info->size))
 493                 goto done;
 494
 495         pos += digest_info->size;
 496
 497         err = 0;
 498
 499         if (req->dst_len < dst_len - pos)
 500                 err = -EOVERFLOW;
 501         req->dst_len = dst_len - pos;
 502
 503         if (!err)
 504                 sg_copy_from_buffer(req->dst,
 505                                 sg_nents_for_len(req->dst, req->dst_len),
 506                                 out_buf + pos, req->dst_len);
 507 done:
 508         kzfree(req_ctx->out_buf);
 509
 510         return err;
 511 }
 512
 513 static void pkcs1pad_verify_complete_cb(
 514                 struct crypto_async_request *child_async_req, int err)
 515 {
 516         struct akcipher_request *req = child_async_req->data;
 517         struct crypto_async_request async_req;
 518
 519         if (err == -EINPROGRESS)
 520                 return;
 521
 522         async_req.data = req->base.data;
 523         async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
 524         async_req.flags = child_async_req->flags;
 525         req->base.complete(&async_req, pkcs1pad_verify_complete(req, err));
 526 }
 527
 528 /*
 529  * The verify operation is here for completeness similar to the verification
 530  * defined in RFC2313 section 10.2 except that block type 0 is not accepted,
 531  * as in RFC2437.  RFC2437 section 9.2 doesn't define any operation to
 532  * retrieve the DigestInfo from a signature, instead the user is expected
 533  * to call the sign operation to generate the expected signature and compare
 534  * signatures instead of the message-digests.
 535  */
 536 static int pkcs1pad_verify(struct akcipher_request *req)
 537 {
 538         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 539         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 540         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 541         int err;
 542
 543         if (!ctx->key_size || req->src_len < ctx->key_size)
 544                 return -EINVAL;
 545
 546         req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
 547         if (!req_ctx->out_buf)
 548                 return -ENOMEM;
 549
 550         pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
 551                             ctx->key_size, NULL);
 552
 553         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 554         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 555                         pkcs1pad_verify_complete_cb, req);
 556
 557         /* Reuse input buffer, output to a new buffer */
 558         akcipher_request_set_crypt(&req_ctx->child_req, req->src,
 559                                    req_ctx->out_sg, req->src_len,
 560                                    ctx->key_size);
 561
 562         err = crypto_akcipher_verify(&req_ctx->child_req);
 563         if (err != -EINPROGRESS &&
 564                         (err != -EBUSY ||
 565                          !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
 566                 return pkcs1pad_verify_complete(req, err);
 567
 568         return err;
 569 }
 570
 571 static int pkcs1pad_init_tfm(struct crypto_akcipher *tfm)
 572 {
 573         struct akcipher_instance *inst = akcipher_alg_instance(tfm);
 574         struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
 575         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 576         struct crypto_akcipher *child_tfm;
 577
 578         child_tfm = crypto_spawn_akcipher(&ictx->spawn);
 579         if (IS_ERR(child_tfm))
 580                 return PTR_ERR(child_tfm);
 581
 582         ctx->child = child_tfm;
 583         return 0;
 584 }
 585
 586 static void pkcs1pad_exit_tfm(struct crypto_akcipher *tfm)
 587 {
 588         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 589
 590         crypto_free_akcipher(ctx->child);
 591 }
 592
 593 static void pkcs1pad_free(struct akcipher_instance *inst)
 594 {
 595         struct pkcs1pad_inst_ctx *ctx = akcipher_instance_ctx(inst);
 596         struct crypto_akcipher_spawn *spawn = &ctx->spawn;
 597
 598         crypto_drop_akcipher(spawn);
 599         kfree(inst);
 600 }
 601
 602 static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)
 603 {
 604         const struct rsa_asn1_template *digest_info;
 605         struct crypto_attr_type *algt;
 606         struct akcipher_instance *inst;
 607         struct pkcs1pad_inst_ctx *ctx;
 608         struct crypto_akcipher_spawn *spawn;
 609         struct akcipher_alg *rsa_alg;
 610         const char *rsa_alg_name;
 611         const char *hash_name;
 612         int err;
 613
 614         algt = crypto_get_attr_type(tb);
 615         if (IS_ERR(algt))
 616                 return PTR_ERR(algt);
 617
 618         if ((algt->type ^ CRYPTO_ALG_TYPE_AKCIPHER) & algt->mask)
 619                 return -EINVAL;
 620
 621         rsa_alg_name = crypto_attr_alg_name(tb[1]);
 622         if (IS_ERR(rsa_alg_name))
 623                 return PTR_ERR(rsa_alg_name);
 624
 625         hash_name = crypto_attr_alg_name(tb[2]);
 626         if (IS_ERR(hash_name))
 627                 return PTR_ERR(hash_name);
 628
 629         digest_info = rsa_lookup_asn1(hash_name);
 630         if (!digest_info)
 631                 return -EINVAL;
 632
 633         inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
 634         if (!inst)
 635                 return -ENOMEM;
 636
 637         ctx = akcipher_instance_ctx(inst);
 638         spawn = &ctx->spawn;
 639         ctx->digest_info = digest_info;
 640
 641         crypto_set_spawn(&spawn->base, akcipher_crypto_instance(inst));
 642         err = crypto_grab_akcipher(spawn, rsa_alg_name, 0,
 643                         crypto_requires_sync(algt->type, algt->mask));
 644         if (err)
 645                 goto out_free_inst;
 646
 647         rsa_alg = crypto_spawn_akcipher_alg(spawn);
 648
 649         err = -ENAMETOOLONG;
 650
 651         if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
 652                      "pkcs1pad(%s,%s)", rsa_alg->base.cra_name, hash_name) >=
 653             CRYPTO_MAX_ALG_NAME ||
 654             snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 655                      "pkcs1pad(%s,%s)",
 656                      rsa_alg->base.cra_driver_name, hash_name) >=
 657             CRYPTO_MAX_ALG_NAME)
 658                 goto out_drop_alg;
 659
 660         inst->alg.base.cra_flags = rsa_alg->base.cra_flags & CRYPTO_ALG_ASYNC;
 661         inst->alg.base.cra_priority = rsa_alg->base.cra_priority;
 662         inst->alg.base.cra_ctxsize = sizeof(struct pkcs1pad_ctx);
 663
 664         inst->alg.init = pkcs1pad_init_tfm;
 665         inst->alg.exit = pkcs1pad_exit_tfm;
 666
 667         inst->alg.encrypt = pkcs1pad_encrypt;
 668         inst->alg.decrypt = pkcs1pad_decrypt;
 669         inst->alg.sign = pkcs1pad_sign;
 670         inst->alg.verify = pkcs1pad_verify;
 671         inst->alg.set_pub_key = pkcs1pad_set_pub_key;
 672         inst->alg.set_priv_key = pkcs1pad_set_priv_key;
 673         inst->alg.max_size = pkcs1pad_get_max_size;
 674         inst->alg.reqsize = sizeof(struct pkcs1pad_request) + rsa_alg->reqsize;
 675
 676         inst->free = pkcs1pad_free;
 677
 678         err = akcipher_register_instance(tmpl, inst);
 679         if (err)
 680                 goto out_drop_alg;
 681
 682         return 0;
 683
 684 out_drop_alg:
 685         crypto_drop_akcipher(spawn);
 686 out_free_inst:
 687         kfree(inst);
 688         return err;
 689 }
 690
 691 struct crypto_template rsa_pkcs1pad_tmpl = {
 692         .name = "pkcs1pad",
 693         .create = pkcs1pad_create,
 694         .module = THIS_MODULE,
 695 };