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         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 265         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 266                         pkcs1pad_encrypt_sign_complete_cb, req);
 267
 268         /* Reuse output buffer */
 269         akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
 270                                    req->dst, ctx->key_size - 1, req->dst_len);
 271
 272         err = crypto_akcipher_encrypt(&req_ctx->child_req);
 273         if (err != -EINPROGRESS &&
 274                         (err != -EBUSY ||
 275                          !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
 276                 return pkcs1pad_encrypt_sign_complete(req, err);
 277
 278         return err;
 279 }
 280
 281 static int pkcs1pad_decrypt_complete(struct akcipher_request *req, int err)
 282 {
 283         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 284         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 285         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 286         unsigned int dst_len;
 287         unsigned int pos;
 288         u8 *out_buf;
 289
 290         if (err)
 291                 goto done;
 292
 293         err = -EINVAL;
 294         dst_len = req_ctx->child_req.dst_len;
 295         if (dst_len < ctx->key_size - 1)
 296                 goto done;
 297
 298         out_buf = req_ctx->out_buf;
 299         if (dst_len == ctx->key_size) {
 300                 if (out_buf[0] != 0x00)
 301                         /* Decrypted value had no leading 0 byte */
 302                         goto done;
 303
 304                 dst_len--;
 305                 out_buf++;
 306         }
 307
 308         if (out_buf[0] != 0x02)
 309                 goto done;
 310
 311         for (pos = 1; pos < dst_len; pos++)
 312                 if (out_buf[pos] == 0x00)
 313                         break;
 314         if (pos < 9 || pos == dst_len)
 315                 goto done;
 316         pos++;
 317
 318         err = 0;
 319
 320         if (req->dst_len < dst_len - pos)
 321                 err = -EOVERFLOW;
 322         req->dst_len = dst_len - pos;
 323
 324         if (!err)
 325                 sg_copy_from_buffer(req->dst,
 326                                 sg_nents_for_len(req->dst, req->dst_len),
 327                                 out_buf + pos, req->dst_len);
 328
 329 done:
 330         kzfree(req_ctx->out_buf);
 331
 332         return err;
 333 }
 334
 335 static void pkcs1pad_decrypt_complete_cb(
 336                 struct crypto_async_request *child_async_req, int err)
 337 {
 338         struct akcipher_request *req = child_async_req->data;
 339         struct crypto_async_request async_req;
 340
 341         if (err == -EINPROGRESS)
 342                 return;
 343
 344         async_req.data = req->base.data;
 345         async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
 346         async_req.flags = child_async_req->flags;
 347         req->base.complete(&async_req, pkcs1pad_decrypt_complete(req, err));
 348 }
 349
 350 static int pkcs1pad_decrypt(struct akcipher_request *req)
 351 {
 352         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 353         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 354         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 355         int err;
 356
 357         if (!ctx->key_size || req->src_len != ctx->key_size)
 358                 return -EINVAL;
 359
 360         req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
 361         if (!req_ctx->out_buf)
 362                 return -ENOMEM;
 363
 364         pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
 365                             ctx->key_size, NULL);
 366
 367         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 368         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 369                         pkcs1pad_decrypt_complete_cb, req);
 370
 371         /* Reuse input buffer, output to a new buffer */
 372         akcipher_request_set_crypt(&req_ctx->child_req, req->src,
 373                                    req_ctx->out_sg, req->src_len,
 374                                    ctx->key_size);
 375
 376         err = crypto_akcipher_decrypt(&req_ctx->child_req);
 377         if (err != -EINPROGRESS &&
 378                         (err != -EBUSY ||
 379                          !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
 380                 return pkcs1pad_decrypt_complete(req, err);
 381
 382         return err;
 383 }
 384
 385 static int pkcs1pad_sign(struct akcipher_request *req)
 386 {
 387         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 388         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 389         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 390         struct akcipher_instance *inst = akcipher_alg_instance(tfm);
 391         struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
 392         const struct rsa_asn1_template *digest_info = ictx->digest_info;
 393         int err;
 394         unsigned int ps_end, digest_size = 0;
 395
 396         if (!ctx->key_size)
 397                 return -EINVAL;
 398
 399         digest_size = digest_info->size;
 400
 401         if (req->src_len + digest_size > ctx->key_size - 11)
 402                 return -EOVERFLOW;
 403
 404         if (req->dst_len < ctx->key_size) {
 405                 req->dst_len = ctx->key_size;
 406                 return -EOVERFLOW;
 407         }
 408
 409         req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
 410                                   GFP_KERNEL);
 411         if (!req_ctx->in_buf)
 412                 return -ENOMEM;
 413
 414         ps_end = ctx->key_size - digest_size - req->src_len - 2;
 415         req_ctx->in_buf[0] = 0x01;
 416         memset(req_ctx->in_buf + 1, 0xff, ps_end - 1);
 417         req_ctx->in_buf[ps_end] = 0x00;
 418
 419         memcpy(req_ctx->in_buf + ps_end + 1, digest_info->data,
 420                digest_info->size);
 421
 422         pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
 423                         ctx->key_size - 1 - req->src_len, req->src);
 424
 425         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 426         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 427                         pkcs1pad_encrypt_sign_complete_cb, req);
 428
 429         /* Reuse output buffer */
 430         akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
 431                                    req->dst, ctx->key_size - 1, req->dst_len);
 432
 433         err = crypto_akcipher_sign(&req_ctx->child_req);
 434         if (err != -EINPROGRESS &&
 435                         (err != -EBUSY ||
 436                          !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
 437                 return pkcs1pad_encrypt_sign_complete(req, err);
 438
 439         return err;
 440 }
 441
 442 static int pkcs1pad_verify_complete(struct akcipher_request *req, int err)
 443 {
 444         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 445         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 446         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 447         struct akcipher_instance *inst = akcipher_alg_instance(tfm);
 448         struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
 449         const struct rsa_asn1_template *digest_info = ictx->digest_info;
 450         unsigned int dst_len;
 451         unsigned int pos;
 452         u8 *out_buf;
 453
 454         if (err)
 455                 goto done;
 456
 457         err = -EINVAL;
 458         dst_len = req_ctx->child_req.dst_len;
 459         if (dst_len < ctx->key_size - 1)
 460                 goto done;
 461
 462         out_buf = req_ctx->out_buf;
 463         if (dst_len == ctx->key_size) {
 464                 if (out_buf[0] != 0x00)
 465                         /* Decrypted value had no leading 0 byte */
 466                         goto done;
 467
 468                 dst_len--;
 469                 out_buf++;
 470         }
 471
 472         err = -EBADMSG;
 473         if (out_buf[0] != 0x01)
 474                 goto done;
 475
 476         for (pos = 1; pos < dst_len; pos++)
 477                 if (out_buf[pos] != 0xff)
 478                         break;
 479
 480         if (pos < 9 || pos == dst_len || out_buf[pos] != 0x00)
 481                 goto done;
 482         pos++;
 483
 484         if (crypto_memneq(out_buf + pos, digest_info->data, digest_info->size))
 485                 goto done;
 486
 487         pos += digest_info->size;
 488
 489         err = 0;
 490
 491         if (req->dst_len < dst_len - pos)
 492                 err = -EOVERFLOW;
 493         req->dst_len = dst_len - pos;
 494
 495         if (!err)
 496                 sg_copy_from_buffer(req->dst,
 497                                 sg_nents_for_len(req->dst, req->dst_len),
 498                                 out_buf + pos, req->dst_len);
 499 done:
 500         kzfree(req_ctx->out_buf);
 501
 502         return err;
 503 }
 504
 505 static void pkcs1pad_verify_complete_cb(
 506                 struct crypto_async_request *child_async_req, int err)
 507 {
 508         struct akcipher_request *req = child_async_req->data;
 509         struct crypto_async_request async_req;
 510
 511         if (err == -EINPROGRESS)
 512                 return;
 513
 514         async_req.data = req->base.data;
 515         async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
 516         async_req.flags = child_async_req->flags;
 517         req->base.complete(&async_req, pkcs1pad_verify_complete(req, err));
 518 }
 519
 520 /*
 521  * The verify operation is here for completeness similar to the verification
 522  * defined in RFC2313 section 10.2 except that block type 0 is not accepted,
 523  * as in RFC2437.  RFC2437 section 9.2 doesn't define any operation to
 524  * retrieve the DigestInfo from a signature, instead the user is expected
 525  * to call the sign operation to generate the expected signature and compare
 526  * signatures instead of the message-digests.
 527  */
 528 static int pkcs1pad_verify(struct akcipher_request *req)
 529 {
 530         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 531         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 532         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 533         int err;
 534
 535         if (!ctx->key_size || req->src_len < ctx->key_size)
 536                 return -EINVAL;
 537
 538         req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
 539         if (!req_ctx->out_buf)
 540                 return -ENOMEM;
 541
 542         pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
 543                             ctx->key_size, NULL);
 544
 545         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 546         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 547                         pkcs1pad_verify_complete_cb, req);
 548
 549         /* Reuse input buffer, output to a new buffer */
 550         akcipher_request_set_crypt(&req_ctx->child_req, req->src,
 551                                    req_ctx->out_sg, req->src_len,
 552                                    ctx->key_size);
 553
 554         err = crypto_akcipher_verify(&req_ctx->child_req);
 555         if (err != -EINPROGRESS &&
 556                         (err != -EBUSY ||
 557                          !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
 558                 return pkcs1pad_verify_complete(req, err);
 559
 560         return err;
 561 }
 562
 563 static int pkcs1pad_init_tfm(struct crypto_akcipher *tfm)
 564 {
 565         struct akcipher_instance *inst = akcipher_alg_instance(tfm);
 566         struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
 567         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 568         struct crypto_akcipher *child_tfm;
 569
 570         child_tfm = crypto_spawn_akcipher(&ictx->spawn);
 571         if (IS_ERR(child_tfm))
 572                 return PTR_ERR(child_tfm);
 573
 574         ctx->child = child_tfm;
 575         return 0;
 576 }
 577
 578 static void pkcs1pad_exit_tfm(struct crypto_akcipher *tfm)
 579 {
 580         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 581
 582         crypto_free_akcipher(ctx->child);
 583 }
 584
 585 static void pkcs1pad_free(struct akcipher_instance *inst)
 586 {
 587         struct pkcs1pad_inst_ctx *ctx = akcipher_instance_ctx(inst);
 588         struct crypto_akcipher_spawn *spawn = &ctx->spawn;
 589
 590         crypto_drop_akcipher(spawn);
 591         kfree(inst);
 592 }
 593
 594 static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)
 595 {
 596         const struct rsa_asn1_template *digest_info;
 597         struct crypto_attr_type *algt;
 598         struct akcipher_instance *inst;
 599         struct pkcs1pad_inst_ctx *ctx;
 600         struct crypto_akcipher_spawn *spawn;
 601         struct akcipher_alg *rsa_alg;
 602         const char *rsa_alg_name;
 603         const char *hash_name;
 604         int err;
 605
 606         algt = crypto_get_attr_type(tb);
 607         if (IS_ERR(algt))
 608                 return PTR_ERR(algt);
 609
 610         if ((algt->type ^ CRYPTO_ALG_TYPE_AKCIPHER) & algt->mask)
 611                 return -EINVAL;
 612
 613         rsa_alg_name = crypto_attr_alg_name(tb[1]);
 614         if (IS_ERR(rsa_alg_name))
 615                 return PTR_ERR(rsa_alg_name);
 616
 617         hash_name = crypto_attr_alg_name(tb[2]);
 618         if (IS_ERR(hash_name))
 619                 return PTR_ERR(hash_name);
 620
 621         digest_info = rsa_lookup_asn1(hash_name);
 622         if (!digest_info)
 623                 return -EINVAL;
 624
 625         inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
 626         if (!inst)
 627                 return -ENOMEM;
 628
 629         ctx = akcipher_instance_ctx(inst);
 630         spawn = &ctx->spawn;
 631         ctx->digest_info = digest_info;
 632
 633         crypto_set_spawn(&spawn->base, akcipher_crypto_instance(inst));
 634         err = crypto_grab_akcipher(spawn, rsa_alg_name, 0,
 635                         crypto_requires_sync(algt->type, algt->mask));
 636         if (err)
 637                 goto out_free_inst;
 638
 639         rsa_alg = crypto_spawn_akcipher_alg(spawn);
 640
 641         err = -ENAMETOOLONG;
 642
 643         if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
 644                      "pkcs1pad(%s,%s)", rsa_alg->base.cra_name, hash_name) >=
 645             CRYPTO_MAX_ALG_NAME ||
 646             snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 647                      "pkcs1pad(%s,%s)",
 648                      rsa_alg->base.cra_driver_name, hash_name) >=
 649             CRYPTO_MAX_ALG_NAME)
 650                 goto out_drop_alg;
 651
 652         inst->alg.base.cra_flags = rsa_alg->base.cra_flags & CRYPTO_ALG_ASYNC;
 653         inst->alg.base.cra_priority = rsa_alg->base.cra_priority;
 654         inst->alg.base.cra_ctxsize = sizeof(struct pkcs1pad_ctx);
 655
 656         inst->alg.init = pkcs1pad_init_tfm;
 657         inst->alg.exit = pkcs1pad_exit_tfm;
 658
 659         inst->alg.encrypt = pkcs1pad_encrypt;
 660         inst->alg.decrypt = pkcs1pad_decrypt;
 661         inst->alg.sign = pkcs1pad_sign;
 662         inst->alg.verify = pkcs1pad_verify;
 663         inst->alg.set_pub_key = pkcs1pad_set_pub_key;
 664         inst->alg.set_priv_key = pkcs1pad_set_priv_key;
 665         inst->alg.max_size = pkcs1pad_get_max_size;
 666         inst->alg.reqsize = sizeof(struct pkcs1pad_request) + rsa_alg->reqsize;
 667
 668         inst->free = pkcs1pad_free;
 669
 670         err = akcipher_register_instance(tmpl, inst);
 671         if (err)
 672                 goto out_drop_alg;
 673
 674         return 0;
 675
 676 out_drop_alg:
 677         crypto_drop_akcipher(spawn);
 678 out_free_inst:
 679         kfree(inst);
 680         return err;
 681 }
 682
 683 struct crypto_template rsa_pkcs1pad_tmpl = {
 684         .name = "pkcs1pad",
 685         .create = pkcs1pad_create,
 686         .module = THIS_MODULE,
 687 };