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         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 271         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 272                         pkcs1pad_encrypt_sign_complete_cb, req);
 273
 274         /* Reuse output buffer */
 275         akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
 276                                    req->dst, ctx->key_size - 1, req->dst_len);
 277
 278         err = crypto_akcipher_encrypt(&req_ctx->child_req);
 279         if (err != -EINPROGRESS &&
 280                         (err != -EBUSY ||
 281                          !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
 282                 return pkcs1pad_encrypt_sign_complete(req, err);
 283
 284         return err;
 285 }
 286
 287 static int pkcs1pad_decrypt_complete(struct akcipher_request *req, int err)
 288 {
 289         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 290         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 291         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 292         unsigned int dst_len;
 293         unsigned int pos;
 294         u8 *out_buf;
 295
 296         if (err)
 297                 goto done;
 298
 299         err = -EINVAL;
 300         dst_len = req_ctx->child_req.dst_len;
 301         if (dst_len < ctx->key_size - 1)
 302                 goto done;
 303
 304         out_buf = req_ctx->out_buf;
 305         if (dst_len == ctx->key_size) {
 306                 if (out_buf[0] != 0x00)
 307                         /* Decrypted value had no leading 0 byte */
 308                         goto done;
 309
 310                 dst_len--;
 311                 out_buf++;
 312         }
 313
 314         if (out_buf[0] != 0x02)
 315                 goto done;
 316
 317         for (pos = 1; pos < dst_len; pos++)
 318                 if (out_buf[pos] == 0x00)
 319                         break;
 320         if (pos < 9 || pos == dst_len)
 321                 goto done;
 322         pos++;
 323
 324         err = 0;
 325
 326         if (req->dst_len < dst_len - pos)
 327                 err = -EOVERFLOW;
 328         req->dst_len = dst_len - pos;
 329
 330         if (!err)
 331                 sg_copy_from_buffer(req->dst,
 332                                 sg_nents_for_len(req->dst, req->dst_len),
 333                                 out_buf + pos, req->dst_len);
 334
 335 done:
 336         kzfree(req_ctx->out_buf);
 337
 338         return err;
 339 }
 340
 341 static void pkcs1pad_decrypt_complete_cb(
 342                 struct crypto_async_request *child_async_req, int err)
 343 {
 344         struct akcipher_request *req = child_async_req->data;
 345         struct crypto_async_request async_req;
 346
 347         if (err == -EINPROGRESS)
 348                 return;
 349
 350         async_req.data = req->base.data;
 351         async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
 352         async_req.flags = child_async_req->flags;
 353         req->base.complete(&async_req, pkcs1pad_decrypt_complete(req, err));
 354 }
 355
 356 static int pkcs1pad_decrypt(struct akcipher_request *req)
 357 {
 358         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 359         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 360         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 361         int err;
 362
 363         if (!ctx->key_size || req->src_len != ctx->key_size)
 364                 return -EINVAL;
 365
 366         req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
 367         if (!req_ctx->out_buf)
 368                 return -ENOMEM;
 369
 370         pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
 371                             ctx->key_size, NULL);
 372
 373         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 374         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 375                         pkcs1pad_decrypt_complete_cb, req);
 376
 377         /* Reuse input buffer, output to a new buffer */
 378         akcipher_request_set_crypt(&req_ctx->child_req, req->src,
 379                                    req_ctx->out_sg, req->src_len,
 380                                    ctx->key_size);
 381
 382         err = crypto_akcipher_decrypt(&req_ctx->child_req);
 383         if (err != -EINPROGRESS &&
 384                         (err != -EBUSY ||
 385                          !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
 386                 return pkcs1pad_decrypt_complete(req, err);
 387
 388         return err;
 389 }
 390
 391 static int pkcs1pad_sign(struct akcipher_request *req)
 392 {
 393         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 394         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 395         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 396         struct akcipher_instance *inst = akcipher_alg_instance(tfm);
 397         struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
 398         const struct rsa_asn1_template *digest_info = ictx->digest_info;
 399         int err;
 400         unsigned int ps_end, digest_size = 0;
 401
 402         if (!ctx->key_size)
 403                 return -EINVAL;
 404
 405         digest_size = digest_info->size;
 406
 407         if (req->src_len + digest_size > ctx->key_size - 11)
 408                 return -EOVERFLOW;
 409
 410         if (req->dst_len < ctx->key_size) {
 411                 req->dst_len = ctx->key_size;
 412                 return -EOVERFLOW;
 413         }
 414
 415         req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
 416                                   GFP_KERNEL);
 417         if (!req_ctx->in_buf)
 418                 return -ENOMEM;
 419
 420         ps_end = ctx->key_size - digest_size - req->src_len - 2;
 421         req_ctx->in_buf[0] = 0x01;
 422         memset(req_ctx->in_buf + 1, 0xff, ps_end - 1);
 423         req_ctx->in_buf[ps_end] = 0x00;
 424
 425         memcpy(req_ctx->in_buf + ps_end + 1, digest_info->data,
 426                digest_info->size);
 427
 428         pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
 429                         ctx->key_size - 1 - req->src_len, req->src);
 430
 431         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 432         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 433                         pkcs1pad_encrypt_sign_complete_cb, req);
 434
 435         /* Reuse output buffer */
 436         akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
 437                                    req->dst, ctx->key_size - 1, req->dst_len);
 438
 439         err = crypto_akcipher_sign(&req_ctx->child_req);
 440         if (err != -EINPROGRESS &&
 441                         (err != -EBUSY ||
 442                          !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
 443                 return pkcs1pad_encrypt_sign_complete(req, err);
 444
 445         return err;
 446 }
 447
 448 static int pkcs1pad_verify_complete(struct akcipher_request *req, int err)
 449 {
 450         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 451         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 452         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 453         struct akcipher_instance *inst = akcipher_alg_instance(tfm);
 454         struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
 455         const struct rsa_asn1_template *digest_info = ictx->digest_info;
 456         unsigned int dst_len;
 457         unsigned int pos;
 458         u8 *out_buf;
 459
 460         if (err)
 461                 goto done;
 462
 463         err = -EINVAL;
 464         dst_len = req_ctx->child_req.dst_len;
 465         if (dst_len < ctx->key_size - 1)
 466                 goto done;
 467
 468         out_buf = req_ctx->out_buf;
 469         if (dst_len == ctx->key_size) {
 470                 if (out_buf[0] != 0x00)
 471                         /* Decrypted value had no leading 0 byte */
 472                         goto done;
 473
 474                 dst_len--;
 475                 out_buf++;
 476         }
 477
 478         err = -EBADMSG;
 479         if (out_buf[0] != 0x01)
 480                 goto done;
 481
 482         for (pos = 1; pos < dst_len; pos++)
 483                 if (out_buf[pos] != 0xff)
 484                         break;
 485
 486         if (pos < 9 || pos == dst_len || out_buf[pos] != 0x00)
 487                 goto done;
 488         pos++;
 489
 490         if (crypto_memneq(out_buf + pos, digest_info->data, digest_info->size))
 491                 goto done;
 492
 493         pos += digest_info->size;
 494
 495         err = 0;
 496
 497         if (req->dst_len < dst_len - pos)
 498                 err = -EOVERFLOW;
 499         req->dst_len = dst_len - pos;
 500
 501         if (!err)
 502                 sg_copy_from_buffer(req->dst,
 503                                 sg_nents_for_len(req->dst, req->dst_len),
 504                                 out_buf + pos, req->dst_len);
 505 done:
 506         kzfree(req_ctx->out_buf);
 507
 508         return err;
 509 }
 510
 511 static void pkcs1pad_verify_complete_cb(
 512                 struct crypto_async_request *child_async_req, int err)
 513 {
 514         struct akcipher_request *req = child_async_req->data;
 515         struct crypto_async_request async_req;
 516
 517         if (err == -EINPROGRESS)
 518                 return;
 519
 520         async_req.data = req->base.data;
 521         async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
 522         async_req.flags = child_async_req->flags;
 523         req->base.complete(&async_req, pkcs1pad_verify_complete(req, err));
 524 }
 525
 526 /*
 527  * The verify operation is here for completeness similar to the verification
 528  * defined in RFC2313 section 10.2 except that block type 0 is not accepted,
 529  * as in RFC2437.  RFC2437 section 9.2 doesn't define any operation to
 530  * retrieve the DigestInfo from a signature, instead the user is expected
 531  * to call the sign operation to generate the expected signature and compare
 532  * signatures instead of the message-digests.
 533  */
 534 static int pkcs1pad_verify(struct akcipher_request *req)
 535 {
 536         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 537         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 538         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 539         int err;
 540
 541         if (!ctx->key_size || req->src_len < ctx->key_size)
 542                 return -EINVAL;
 543
 544         req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
 545         if (!req_ctx->out_buf)
 546                 return -ENOMEM;
 547
 548         pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
 549                             ctx->key_size, NULL);
 550
 551         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 552         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 553                         pkcs1pad_verify_complete_cb, req);
 554
 555         /* Reuse input buffer, output to a new buffer */
 556         akcipher_request_set_crypt(&req_ctx->child_req, req->src,
 557                                    req_ctx->out_sg, req->src_len,
 558                                    ctx->key_size);
 559
 560         err = crypto_akcipher_verify(&req_ctx->child_req);
 561         if (err != -EINPROGRESS &&
 562                         (err != -EBUSY ||
 563                          !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
 564                 return pkcs1pad_verify_complete(req, err);
 565
 566         return err;
 567 }
 568
 569 static int pkcs1pad_init_tfm(struct crypto_akcipher *tfm)
 570 {
 571         struct akcipher_instance *inst = akcipher_alg_instance(tfm);
 572         struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
 573         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 574         struct crypto_akcipher *child_tfm;
 575
 576         child_tfm = crypto_spawn_akcipher(&ictx->spawn);
 577         if (IS_ERR(child_tfm))
 578                 return PTR_ERR(child_tfm);
 579
 580         ctx->child = child_tfm;
 581         return 0;
 582 }
 583
 584 static void pkcs1pad_exit_tfm(struct crypto_akcipher *tfm)
 585 {
 586         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 587
 588         crypto_free_akcipher(ctx->child);
 589 }
 590
 591 static void pkcs1pad_free(struct akcipher_instance *inst)
 592 {
 593         struct pkcs1pad_inst_ctx *ctx = akcipher_instance_ctx(inst);
 594         struct crypto_akcipher_spawn *spawn = &ctx->spawn;
 595
 596         crypto_drop_akcipher(spawn);
 597         kfree(inst);
 598 }
 599
 600 static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)
 601 {
 602         const struct rsa_asn1_template *digest_info;
 603         struct crypto_attr_type *algt;
 604         struct akcipher_instance *inst;
 605         struct pkcs1pad_inst_ctx *ctx;
 606         struct crypto_akcipher_spawn *spawn;
 607         struct akcipher_alg *rsa_alg;
 608         const char *rsa_alg_name;
 609         const char *hash_name;
 610         int err;
 611
 612         algt = crypto_get_attr_type(tb);
 613         if (IS_ERR(algt))
 614                 return PTR_ERR(algt);
 615
 616         if ((algt->type ^ CRYPTO_ALG_TYPE_AKCIPHER) & algt->mask)
 617                 return -EINVAL;
 618
 619         rsa_alg_name = crypto_attr_alg_name(tb[1]);
 620         if (IS_ERR(rsa_alg_name))
 621                 return PTR_ERR(rsa_alg_name);
 622
 623         hash_name = crypto_attr_alg_name(tb[2]);
 624         if (IS_ERR(hash_name))
 625                 return PTR_ERR(hash_name);
 626
 627         digest_info = rsa_lookup_asn1(hash_name);
 628         if (!digest_info)
 629                 return -EINVAL;
 630
 631         inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
 632         if (!inst)
 633                 return -ENOMEM;
 634
 635         ctx = akcipher_instance_ctx(inst);
 636         spawn = &ctx->spawn;
 637         ctx->digest_info = digest_info;
 638
 639         crypto_set_spawn(&spawn->base, akcipher_crypto_instance(inst));
 640         err = crypto_grab_akcipher(spawn, rsa_alg_name, 0,
 641                         crypto_requires_sync(algt->type, algt->mask));
 642         if (err)
 643                 goto out_free_inst;
 644
 645         rsa_alg = crypto_spawn_akcipher_alg(spawn);
 646
 647         err = -ENAMETOOLONG;
 648
 649         if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
 650                      "pkcs1pad(%s,%s)", rsa_alg->base.cra_name, hash_name) >=
 651             CRYPTO_MAX_ALG_NAME ||
 652             snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 653                      "pkcs1pad(%s,%s)",
 654                      rsa_alg->base.cra_driver_name, hash_name) >=
 655             CRYPTO_MAX_ALG_NAME)
 656                 goto out_drop_alg;
 657
 658         inst->alg.base.cra_flags = rsa_alg->base.cra_flags & CRYPTO_ALG_ASYNC;
 659         inst->alg.base.cra_priority = rsa_alg->base.cra_priority;
 660         inst->alg.base.cra_ctxsize = sizeof(struct pkcs1pad_ctx);
 661
 662         inst->alg.init = pkcs1pad_init_tfm;
 663         inst->alg.exit = pkcs1pad_exit_tfm;
 664
 665         inst->alg.encrypt = pkcs1pad_encrypt;
 666         inst->alg.decrypt = pkcs1pad_decrypt;
 667         inst->alg.sign = pkcs1pad_sign;
 668         inst->alg.verify = pkcs1pad_verify;
 669         inst->alg.set_pub_key = pkcs1pad_set_pub_key;
 670         inst->alg.set_priv_key = pkcs1pad_set_priv_key;
 671         inst->alg.max_size = pkcs1pad_get_max_size;
 672         inst->alg.reqsize = sizeof(struct pkcs1pad_request) + rsa_alg->reqsize;
 673
 674         inst->free = pkcs1pad_free;
 675
 676         err = akcipher_register_instance(tmpl, inst);
 677         if (err)
 678                 goto out_drop_alg;
 679
 680         return 0;
 681
 682 out_drop_alg:
 683         crypto_drop_akcipher(spawn);
 684 out_free_inst:
 685         kfree(inst);
 686         return err;
 687 }
 688
 689 struct crypto_template rsa_pkcs1pad_tmpl = {
 690         .name = "pkcs1pad",
 691         .create = pkcs1pad_create,
 692         .module = THIS_MODULE,
 693 };