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 > PAGE_SIZE)
 124                 return -ENOTSUPP;
 125
 126         ctx->key_size = err;
 127         return 0;
 128 }
 129
 130 static int pkcs1pad_set_priv_key(struct crypto_akcipher *tfm, const void *key,
 131                 unsigned int keylen)
 132 {
 133         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 134         int err;
 135
 136         ctx->key_size = 0;
 137
 138         err = crypto_akcipher_set_priv_key(ctx->child, key, keylen);
 139         if (err)
 140                 return err;
 141
 142         /* Find out new modulus size from rsa implementation */
 143         err = crypto_akcipher_maxsize(ctx->child);
 144         if (err > PAGE_SIZE)
 145                 return -ENOTSUPP;
 146
 147         ctx->key_size = err;
 148         return 0;
 149 }
 150
 151 static unsigned int pkcs1pad_get_max_size(struct crypto_akcipher *tfm)
 152 {
 153         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 154
 155         /*
 156          * The maximum destination buffer size for the encrypt/sign operations
 157          * will be the same as for RSA, even though it's smaller for
 158          * decrypt/verify.
 159          */
 160
 161         return ctx->key_size;
 162 }
 163
 164 static void pkcs1pad_sg_set_buf(struct scatterlist *sg, void *buf, size_t len,
 165                 struct scatterlist *next)
 166 {
 167         int nsegs = next ? 2 : 1;
 168
 169         sg_init_table(sg, nsegs);
 170         sg_set_buf(sg, buf, len);
 171
 172         if (next)
 173                 sg_chain(sg, nsegs, next);
 174 }
 175
 176 static int pkcs1pad_encrypt_sign_complete(struct akcipher_request *req, int err)
 177 {
 178         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 179         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 180         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 181         unsigned int pad_len;
 182         unsigned int len;
 183         u8 *out_buf;
 184
 185         if (err)
 186                 goto out;
 187
 188         len = req_ctx->child_req.dst_len;
 189         pad_len = ctx->key_size - len;
 190
 191         /* Four billion to one */
 192         if (likely(!pad_len))
 193                 goto out;
 194
 195         out_buf = kzalloc(ctx->key_size, GFP_ATOMIC);
 196         err = -ENOMEM;
 197         if (!out_buf)
 198                 goto out;
 199
 200         sg_copy_to_buffer(req->dst, sg_nents_for_len(req->dst, len),
 201                           out_buf + pad_len, len);
 202         sg_copy_from_buffer(req->dst,
 203                             sg_nents_for_len(req->dst, ctx->key_size),
 204                             out_buf, ctx->key_size);
 205         kzfree(out_buf);
 206
 207 out:
 208         req->dst_len = ctx->key_size;
 209
 210         kfree(req_ctx->in_buf);
 211
 212         return err;
 213 }
 214
 215 static void pkcs1pad_encrypt_sign_complete_cb(
 216                 struct crypto_async_request *child_async_req, int err)
 217 {
 218         struct akcipher_request *req = child_async_req->data;
 219         struct crypto_async_request async_req;
 220
 221         if (err == -EINPROGRESS)
 222                 return;
 223
 224         async_req.data = req->base.data;
 225         async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
 226         async_req.flags = child_async_req->flags;
 227         req->base.complete(&async_req,
 228                         pkcs1pad_encrypt_sign_complete(req, err));
 229 }
 230
 231 static int pkcs1pad_encrypt(struct akcipher_request *req)
 232 {
 233         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 234         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 235         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 236         int err;
 237         unsigned int i, ps_end;
 238
 239         if (!ctx->key_size)
 240                 return -EINVAL;
 241
 242         if (req->src_len > ctx->key_size - 11)
 243                 return -EOVERFLOW;
 244
 245         if (req->dst_len < ctx->key_size) {
 246                 req->dst_len = ctx->key_size;
 247                 return -EOVERFLOW;
 248         }
 249
 250         req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
 251                                   GFP_KERNEL);
 252         if (!req_ctx->in_buf)
 253                 return -ENOMEM;
 254
 255         ps_end = ctx->key_size - req->src_len - 2;
 256         req_ctx->in_buf[0] = 0x02;
 257         for (i = 1; i < ps_end; i++)
 258                 req_ctx->in_buf[i] = 1 + prandom_u32_max(255);
 259         req_ctx->in_buf[ps_end] = 0x00;
 260
 261         pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
 262                         ctx->key_size - 1 - req->src_len, req->src);
 263
 264         req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
 265         if (!req_ctx->out_buf) {
 266                 kfree(req_ctx->in_buf);
 267                 return -ENOMEM;
 268         }
 269
 270         pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
 271                         ctx->key_size, NULL);
 272
 273         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 274         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 275                         pkcs1pad_encrypt_sign_complete_cb, req);
 276
 277         /* Reuse output buffer */
 278         akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
 279                                    req->dst, ctx->key_size - 1, req->dst_len);
 280
 281         err = crypto_akcipher_encrypt(&req_ctx->child_req);
 282         if (err != -EINPROGRESS &&
 283                         (err != -EBUSY ||
 284                          !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
 285                 return pkcs1pad_encrypt_sign_complete(req, err);
 286
 287         return err;
 288 }
 289
 290 static int pkcs1pad_decrypt_complete(struct akcipher_request *req, int err)
 291 {
 292         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 293         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 294         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 295         unsigned int dst_len;
 296         unsigned int pos;
 297         u8 *out_buf;
 298
 299         if (err)
 300                 goto done;
 301
 302         err = -EINVAL;
 303         dst_len = req_ctx->child_req.dst_len;
 304         if (dst_len < ctx->key_size - 1)
 305                 goto done;
 306
 307         out_buf = req_ctx->out_buf;
 308         if (dst_len == ctx->key_size) {
 309                 if (out_buf[0] != 0x00)
 310                         /* Decrypted value had no leading 0 byte */
 311                         goto done;
 312
 313                 dst_len--;
 314                 out_buf++;
 315         }
 316
 317         if (out_buf[0] != 0x02)
 318                 goto done;
 319
 320         for (pos = 1; pos < dst_len; pos++)
 321                 if (out_buf[pos] == 0x00)
 322                         break;
 323         if (pos < 9 || pos == dst_len)
 324                 goto done;
 325         pos++;
 326
 327         err = 0;
 328
 329         if (req->dst_len < dst_len - pos)
 330                 err = -EOVERFLOW;
 331         req->dst_len = dst_len - pos;
 332
 333         if (!err)
 334                 sg_copy_from_buffer(req->dst,
 335                                 sg_nents_for_len(req->dst, req->dst_len),
 336                                 out_buf + pos, req->dst_len);
 337
 338 done:
 339         kzfree(req_ctx->out_buf);
 340
 341         return err;
 342 }
 343
 344 static void pkcs1pad_decrypt_complete_cb(
 345                 struct crypto_async_request *child_async_req, int err)
 346 {
 347         struct akcipher_request *req = child_async_req->data;
 348         struct crypto_async_request async_req;
 349
 350         if (err == -EINPROGRESS)
 351                 return;
 352
 353         async_req.data = req->base.data;
 354         async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
 355         async_req.flags = child_async_req->flags;
 356         req->base.complete(&async_req, pkcs1pad_decrypt_complete(req, err));
 357 }
 358
 359 static int pkcs1pad_decrypt(struct akcipher_request *req)
 360 {
 361         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 362         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 363         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 364         int err;
 365
 366         if (!ctx->key_size || req->src_len != ctx->key_size)
 367                 return -EINVAL;
 368
 369         req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
 370         if (!req_ctx->out_buf)
 371                 return -ENOMEM;
 372
 373         pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
 374                             ctx->key_size, NULL);
 375
 376         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 377         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 378                         pkcs1pad_decrypt_complete_cb, req);
 379
 380         /* Reuse input buffer, output to a new buffer */
 381         akcipher_request_set_crypt(&req_ctx->child_req, req->src,
 382                                    req_ctx->out_sg, req->src_len,
 383                                    ctx->key_size);
 384
 385         err = crypto_akcipher_decrypt(&req_ctx->child_req);
 386         if (err != -EINPROGRESS &&
 387                         (err != -EBUSY ||
 388                          !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
 389                 return pkcs1pad_decrypt_complete(req, err);
 390
 391         return err;
 392 }
 393
 394 static int pkcs1pad_sign(struct akcipher_request *req)
 395 {
 396         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 397         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 398         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 399         struct akcipher_instance *inst = akcipher_alg_instance(tfm);
 400         struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
 401         const struct rsa_asn1_template *digest_info = ictx->digest_info;
 402         int err;
 403         unsigned int ps_end, digest_size = 0;
 404
 405         if (!ctx->key_size)
 406                 return -EINVAL;
 407
 408         digest_size = digest_info->size;
 409
 410         if (req->src_len + digest_size > ctx->key_size - 11)
 411                 return -EOVERFLOW;
 412
 413         if (req->dst_len < ctx->key_size) {
 414                 req->dst_len = ctx->key_size;
 415                 return -EOVERFLOW;
 416         }
 417
 418         req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
 419                                   GFP_KERNEL);
 420         if (!req_ctx->in_buf)
 421                 return -ENOMEM;
 422
 423         ps_end = ctx->key_size - digest_size - req->src_len - 2;
 424         req_ctx->in_buf[0] = 0x01;
 425         memset(req_ctx->in_buf + 1, 0xff, ps_end - 1);
 426         req_ctx->in_buf[ps_end] = 0x00;
 427
 428         memcpy(req_ctx->in_buf + ps_end + 1, digest_info->data,
 429                digest_info->size);
 430
 431         pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
 432                         ctx->key_size - 1 - req->src_len, req->src);
 433
 434         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 435         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 436                         pkcs1pad_encrypt_sign_complete_cb, req);
 437
 438         /* Reuse output buffer */
 439         akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
 440                                    req->dst, ctx->key_size - 1, req->dst_len);
 441
 442         err = crypto_akcipher_sign(&req_ctx->child_req);
 443         if (err != -EINPROGRESS &&
 444                         (err != -EBUSY ||
 445                          !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
 446                 return pkcs1pad_encrypt_sign_complete(req, err);
 447
 448         return err;
 449 }
 450
 451 static int pkcs1pad_verify_complete(struct akcipher_request *req, int err)
 452 {
 453         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 454         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 455         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 456         struct akcipher_instance *inst = akcipher_alg_instance(tfm);
 457         struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
 458         const struct rsa_asn1_template *digest_info = ictx->digest_info;
 459         unsigned int dst_len;
 460         unsigned int pos;
 461         u8 *out_buf;
 462
 463         if (err)
 464                 goto done;
 465
 466         err = -EINVAL;
 467         dst_len = req_ctx->child_req.dst_len;
 468         if (dst_len < ctx->key_size - 1)
 469                 goto done;
 470
 471         out_buf = req_ctx->out_buf;
 472         if (dst_len == ctx->key_size) {
 473                 if (out_buf[0] != 0x00)
 474                         /* Decrypted value had no leading 0 byte */
 475                         goto done;
 476
 477                 dst_len--;
 478                 out_buf++;
 479         }
 480
 481         err = -EBADMSG;
 482         if (out_buf[0] != 0x01)
 483                 goto done;
 484
 485         for (pos = 1; pos < dst_len; pos++)
 486                 if (out_buf[pos] != 0xff)
 487                         break;
 488
 489         if (pos < 9 || pos == dst_len || out_buf[pos] != 0x00)
 490                 goto done;
 491         pos++;
 492
 493         if (crypto_memneq(out_buf + pos, digest_info->data, digest_info->size))
 494                 goto done;
 495
 496         pos += digest_info->size;
 497
 498         err = 0;
 499
 500         if (req->dst_len < dst_len - pos)
 501                 err = -EOVERFLOW;
 502         req->dst_len = dst_len - pos;
 503
 504         if (!err)
 505                 sg_copy_from_buffer(req->dst,
 506                                 sg_nents_for_len(req->dst, req->dst_len),
 507                                 out_buf + pos, req->dst_len);
 508 done:
 509         kzfree(req_ctx->out_buf);
 510
 511         return err;
 512 }
 513
 514 static void pkcs1pad_verify_complete_cb(
 515                 struct crypto_async_request *child_async_req, int err)
 516 {
 517         struct akcipher_request *req = child_async_req->data;
 518         struct crypto_async_request async_req;
 519
 520         if (err == -EINPROGRESS)
 521                 return;
 522
 523         async_req.data = req->base.data;
 524         async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
 525         async_req.flags = child_async_req->flags;
 526         req->base.complete(&async_req, pkcs1pad_verify_complete(req, err));
 527 }
 528
 529 /*
 530  * The verify operation is here for completeness similar to the verification
 531  * defined in RFC2313 section 10.2 except that block type 0 is not accepted,
 532  * as in RFC2437.  RFC2437 section 9.2 doesn't define any operation to
 533  * retrieve the DigestInfo from a signature, instead the user is expected
 534  * to call the sign operation to generate the expected signature and compare
 535  * signatures instead of the message-digests.
 536  */
 537 static int pkcs1pad_verify(struct akcipher_request *req)
 538 {
 539         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 540         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 541         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 542         int err;
 543
 544         if (!ctx->key_size || req->src_len < ctx->key_size)
 545                 return -EINVAL;
 546
 547         req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
 548         if (!req_ctx->out_buf)
 549                 return -ENOMEM;
 550
 551         pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
 552                             ctx->key_size, NULL);
 553
 554         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 555         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 556                         pkcs1pad_verify_complete_cb, req);
 557
 558         /* Reuse input buffer, output to a new buffer */
 559         akcipher_request_set_crypt(&req_ctx->child_req, req->src,
 560                                    req_ctx->out_sg, req->src_len,
 561                                    ctx->key_size);
 562
 563         err = crypto_akcipher_verify(&req_ctx->child_req);
 564         if (err != -EINPROGRESS &&
 565                         (err != -EBUSY ||
 566                          !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
 567                 return pkcs1pad_verify_complete(req, err);
 568
 569         return err;
 570 }
 571
 572 static int pkcs1pad_init_tfm(struct crypto_akcipher *tfm)
 573 {
 574         struct akcipher_instance *inst = akcipher_alg_instance(tfm);
 575         struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
 576         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 577         struct crypto_akcipher *child_tfm;
 578
 579         child_tfm = crypto_spawn_akcipher(&ictx->spawn);
 580         if (IS_ERR(child_tfm))
 581                 return PTR_ERR(child_tfm);
 582
 583         ctx->child = child_tfm;
 584         return 0;
 585 }
 586
 587 static void pkcs1pad_exit_tfm(struct crypto_akcipher *tfm)
 588 {
 589         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 590
 591         crypto_free_akcipher(ctx->child);
 592 }
 593
 594 static void pkcs1pad_free(struct akcipher_instance *inst)
 595 {
 596         struct pkcs1pad_inst_ctx *ctx = akcipher_instance_ctx(inst);
 597         struct crypto_akcipher_spawn *spawn = &ctx->spawn;
 598
 599         crypto_drop_akcipher(spawn);
 600         kfree(inst);
 601 }
 602
 603 static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)
 604 {
 605         const struct rsa_asn1_template *digest_info;
 606         struct crypto_attr_type *algt;
 607         struct akcipher_instance *inst;
 608         struct pkcs1pad_inst_ctx *ctx;
 609         struct crypto_akcipher_spawn *spawn;
 610         struct akcipher_alg *rsa_alg;
 611         const char *rsa_alg_name;
 612         const char *hash_name;
 613         int err;
 614
 615         algt = crypto_get_attr_type(tb);
 616         if (IS_ERR(algt))
 617                 return PTR_ERR(algt);
 618
 619         if ((algt->type ^ CRYPTO_ALG_TYPE_AKCIPHER) & algt->mask)
 620                 return -EINVAL;
 621
 622         rsa_alg_name = crypto_attr_alg_name(tb[1]);
 623         if (IS_ERR(rsa_alg_name))
 624                 return PTR_ERR(rsa_alg_name);
 625
 626         hash_name = crypto_attr_alg_name(tb[2]);
 627         if (IS_ERR(hash_name))
 628                 return PTR_ERR(hash_name);
 629
 630         digest_info = rsa_lookup_asn1(hash_name);
 631         if (!digest_info)
 632                 return -EINVAL;
 633
 634         inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
 635         if (!inst)
 636                 return -ENOMEM;
 637
 638         ctx = akcipher_instance_ctx(inst);
 639         spawn = &ctx->spawn;
 640         ctx->digest_info = digest_info;
 641
 642         crypto_set_spawn(&spawn->base, akcipher_crypto_instance(inst));
 643         err = crypto_grab_akcipher(spawn, rsa_alg_name, 0,
 644                         crypto_requires_sync(algt->type, algt->mask));
 645         if (err)
 646                 goto out_free_inst;
 647
 648         rsa_alg = crypto_spawn_akcipher_alg(spawn);
 649
 650         err = -ENAMETOOLONG;
 651
 652         if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
 653                      "pkcs1pad(%s,%s)", rsa_alg->base.cra_name, hash_name) >=
 654             CRYPTO_MAX_ALG_NAME ||
 655             snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 656                      "pkcs1pad(%s,%s)",
 657                      rsa_alg->base.cra_driver_name, hash_name) >=
 658             CRYPTO_MAX_ALG_NAME)
 659                 goto out_drop_alg;
 660
 661         inst->alg.base.cra_flags = rsa_alg->base.cra_flags & CRYPTO_ALG_ASYNC;
 662         inst->alg.base.cra_priority = rsa_alg->base.cra_priority;
 663         inst->alg.base.cra_ctxsize = sizeof(struct pkcs1pad_ctx);
 664
 665         inst->alg.init = pkcs1pad_init_tfm;
 666         inst->alg.exit = pkcs1pad_exit_tfm;
 667
 668         inst->alg.encrypt = pkcs1pad_encrypt;
 669         inst->alg.decrypt = pkcs1pad_decrypt;
 670         inst->alg.sign = pkcs1pad_sign;
 671         inst->alg.verify = pkcs1pad_verify;
 672         inst->alg.set_pub_key = pkcs1pad_set_pub_key;
 673         inst->alg.set_priv_key = pkcs1pad_set_priv_key;
 674         inst->alg.max_size = pkcs1pad_get_max_size;
 675         inst->alg.reqsize = sizeof(struct pkcs1pad_request) + rsa_alg->reqsize;
 676
 677         inst->free = pkcs1pad_free;
 678
 679         err = akcipher_register_instance(tmpl, inst);
 680         if (err)
 681                 goto out_drop_alg;
 682
 683         return 0;
 684
 685 out_drop_alg:
 686         crypto_drop_akcipher(spawn);
 687 out_free_inst:
 688         kfree(inst);
 689         return err;
 690 }
 691
 692 struct crypto_template rsa_pkcs1pad_tmpl = {
 693         .name = "pkcs1pad",
 694         .create = pkcs1pad_create,
 695         .module = THIS_MODULE,
 696 };