crypto/rsa-pkcs1pad.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * RSA padding templates.
   4  *
   5  * Copyright (c) 2015  Intel Corporation
   6  */
   7
   8 #include <crypto/algapi.h>
   9 #include <crypto/akcipher.h>
  10 #include <crypto/internal/akcipher.h>
  11 #include <crypto/internal/rsa.h>
  12 #include <linux/err.h>
  13 #include <linux/init.h>
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/random.h>
  17
  18 /*
  19  * Hash algorithm OIDs plus ASN.1 DER wrappings [RFC4880 sec 5.2.2].
  20  */
  21 static const u8 rsa_digest_info_md5[] = {
  22         0x30, 0x20, 0x30, 0x0c, 0x06, 0x08,
  23         0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x02, 0x05, /* OID */
  24         0x05, 0x00, 0x04, 0x10
  25 };
  26
  27 static const u8 rsa_digest_info_sha1[] = {
  28         0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
  29         0x2b, 0x0e, 0x03, 0x02, 0x1a,
  30         0x05, 0x00, 0x04, 0x14
  31 };
  32
  33 static const u8 rsa_digest_info_rmd160[] = {
  34         0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
  35         0x2b, 0x24, 0x03, 0x02, 0x01,
  36         0x05, 0x00, 0x04, 0x14
  37 };
  38
  39 static const u8 rsa_digest_info_sha224[] = {
  40         0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09,
  41         0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04,
  42         0x05, 0x00, 0x04, 0x1c
  43 };
  44
  45 static const u8 rsa_digest_info_sha256[] = {
  46         0x30, 0x31, 0x30, 0x0d, 0x06, 0x09,
  47         0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01,
  48         0x05, 0x00, 0x04, 0x20
  49 };
  50
  51 static const u8 rsa_digest_info_sha384[] = {
  52         0x30, 0x41, 0x30, 0x0d, 0x06, 0x09,
  53         0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02,
  54         0x05, 0x00, 0x04, 0x30
  55 };
  56
  57 static const u8 rsa_digest_info_sha512[] = {
  58         0x30, 0x51, 0x30, 0x0d, 0x06, 0x09,
  59         0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03,
  60         0x05, 0x00, 0x04, 0x40
  61 };
  62
  63 static const struct rsa_asn1_template {
  64         const char      *name;
  65         const u8        *data;
  66         size_t          size;
  67 } rsa_asn1_templates[] = {
  68 #define _(X) { #X, rsa_digest_info_##X, sizeof(rsa_digest_info_##X) }
  69         _(md5),
  70         _(sha1),
  71         _(rmd160),
  72         _(sha256),
  73         _(sha384),
  74         _(sha512),
  75         _(sha224),
  76         { NULL }
  77 #undef _
  78 };
  79
  80 static const struct rsa_asn1_template *rsa_lookup_asn1(const char *name)
  81 {
  82         const struct rsa_asn1_template *p;
  83
  84         for (p = rsa_asn1_templates; p->name; p++)
  85                 if (strcmp(name, p->name) == 0)
  86                         return p;
  87         return NULL;
  88 }
  89
  90 struct pkcs1pad_ctx {
  91         struct crypto_akcipher *child;
  92         unsigned int key_size;
  93 };
  94
  95 struct pkcs1pad_inst_ctx {
  96         struct crypto_akcipher_spawn spawn;
  97         const struct rsa_asn1_template *digest_info;
  98 };
  99
 100 struct pkcs1pad_request {
 101         struct scatterlist in_sg[2], out_sg[1];
 102         uint8_t *in_buf, *out_buf;
 103         struct akcipher_request child_req;
 104 };
 105
 106 static int pkcs1pad_set_pub_key(struct crypto_akcipher *tfm, const void *key,
 107                 unsigned int keylen)
 108 {
 109         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 110         int err;
 111
 112         ctx->key_size = 0;
 113
 114         err = crypto_akcipher_set_pub_key(ctx->child, key, keylen);
 115         if (err)
 116                 return err;
 117
 118         /* Find out new modulus size from rsa implementation */
 119         err = crypto_akcipher_maxsize(ctx->child);
 120         if (err > PAGE_SIZE)
 121                 return -ENOTSUPP;
 122
 123         ctx->key_size = err;
 124         return 0;
 125 }
 126
 127 static int pkcs1pad_set_priv_key(struct crypto_akcipher *tfm, const void *key,
 128                 unsigned int keylen)
 129 {
 130         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 131         int err;
 132
 133         ctx->key_size = 0;
 134
 135         err = crypto_akcipher_set_priv_key(ctx->child, key, keylen);
 136         if (err)
 137                 return err;
 138
 139         /* Find out new modulus size from rsa implementation */
 140         err = crypto_akcipher_maxsize(ctx->child);
 141         if (err > PAGE_SIZE)
 142                 return -ENOTSUPP;
 143
 144         ctx->key_size = err;
 145         return 0;
 146 }
 147
 148 static unsigned int pkcs1pad_get_max_size(struct crypto_akcipher *tfm)
 149 {
 150         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 151
 152         /*
 153          * The maximum destination buffer size for the encrypt/sign operations
 154          * will be the same as for RSA, even though it's smaller for
 155          * decrypt/verify.
 156          */
 157
 158         return ctx->key_size;
 159 }
 160
 161 static void pkcs1pad_sg_set_buf(struct scatterlist *sg, void *buf, size_t len,
 162                 struct scatterlist *next)
 163 {
 164         int nsegs = next ? 2 : 1;
 165
 166         sg_init_table(sg, nsegs);
 167         sg_set_buf(sg, buf, len);
 168
 169         if (next)
 170                 sg_chain(sg, nsegs, next);
 171 }
 172
 173 static int pkcs1pad_encrypt_sign_complete(struct akcipher_request *req, int err)
 174 {
 175         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 176         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 177         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 178         unsigned int pad_len;
 179         unsigned int len;
 180         u8 *out_buf;
 181
 182         if (err)
 183                 goto out;
 184
 185         len = req_ctx->child_req.dst_len;
 186         pad_len = ctx->key_size - len;
 187
 188         /* Four billion to one */
 189         if (likely(!pad_len))
 190                 goto out;
 191
 192         out_buf = kzalloc(ctx->key_size, GFP_KERNEL);
 193         err = -ENOMEM;
 194         if (!out_buf)
 195                 goto out;
 196
 197         sg_copy_to_buffer(req->dst, sg_nents_for_len(req->dst, len),
 198                           out_buf + pad_len, len);
 199         sg_copy_from_buffer(req->dst,
 200                             sg_nents_for_len(req->dst, ctx->key_size),
 201                             out_buf, ctx->key_size);
 202         kzfree(out_buf);
 203
 204 out:
 205         req->dst_len = ctx->key_size;
 206
 207         kfree(req_ctx->in_buf);
 208
 209         return err;
 210 }
 211
 212 static void pkcs1pad_encrypt_sign_complete_cb(
 213                 struct crypto_async_request *child_async_req, int err)
 214 {
 215         struct akcipher_request *req = child_async_req->data;
 216         struct crypto_async_request async_req;
 217
 218         if (err == -EINPROGRESS)
 219                 return;
 220
 221         async_req.data = req->base.data;
 222         async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
 223         async_req.flags = child_async_req->flags;
 224         req->base.complete(&async_req,
 225                         pkcs1pad_encrypt_sign_complete(req, err));
 226 }
 227
 228 static int pkcs1pad_encrypt(struct akcipher_request *req)
 229 {
 230         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 231         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 232         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 233         int err;
 234         unsigned int i, ps_end;
 235
 236         if (!ctx->key_size)
 237                 return -EINVAL;
 238
 239         if (req->src_len > ctx->key_size - 11)
 240                 return -EOVERFLOW;
 241
 242         if (req->dst_len < ctx->key_size) {
 243                 req->dst_len = ctx->key_size;
 244                 return -EOVERFLOW;
 245         }
 246
 247         req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
 248                                   GFP_KERNEL);
 249         if (!req_ctx->in_buf)
 250                 return -ENOMEM;
 251
 252         ps_end = ctx->key_size - req->src_len - 2;
 253         req_ctx->in_buf[0] = 0x02;
 254         for (i = 1; i < ps_end; i++)
 255                 req_ctx->in_buf[i] = 1 + prandom_u32_max(255);
 256         req_ctx->in_buf[ps_end] = 0x00;
 257
 258         pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
 259                         ctx->key_size - 1 - req->src_len, req->src);
 260
 261         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 262         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 263                         pkcs1pad_encrypt_sign_complete_cb, req);
 264
 265         /* Reuse output buffer */
 266         akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
 267                                    req->dst, ctx->key_size - 1, req->dst_len);
 268
 269         err = crypto_akcipher_encrypt(&req_ctx->child_req);
 270         if (err != -EINPROGRESS && err != -EBUSY)
 271                 return pkcs1pad_encrypt_sign_complete(req, err);
 272
 273         return err;
 274 }
 275
 276 static int pkcs1pad_decrypt_complete(struct akcipher_request *req, int err)
 277 {
 278         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 279         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 280         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 281         unsigned int dst_len;
 282         unsigned int pos;
 283         u8 *out_buf;
 284
 285         if (err)
 286                 goto done;
 287
 288         err = -EINVAL;
 289         dst_len = req_ctx->child_req.dst_len;
 290         if (dst_len < ctx->key_size - 1)
 291                 goto done;
 292
 293         out_buf = req_ctx->out_buf;
 294         if (dst_len == ctx->key_size) {
 295                 if (out_buf[0] != 0x00)
 296                         /* Decrypted value had no leading 0 byte */
 297                         goto done;
 298
 299                 dst_len--;
 300                 out_buf++;
 301         }
 302
 303         if (out_buf[0] != 0x02)
 304                 goto done;
 305
 306         for (pos = 1; pos < dst_len; pos++)
 307                 if (out_buf[pos] == 0x00)
 308                         break;
 309         if (pos < 9 || pos == dst_len)
 310                 goto done;
 311         pos++;
 312
 313         err = 0;
 314
 315         if (req->dst_len < dst_len - pos)
 316                 err = -EOVERFLOW;
 317         req->dst_len = dst_len - pos;
 318
 319         if (!err)
 320                 sg_copy_from_buffer(req->dst,
 321                                 sg_nents_for_len(req->dst, req->dst_len),
 322                                 out_buf + pos, req->dst_len);
 323
 324 done:
 325         kzfree(req_ctx->out_buf);
 326
 327         return err;
 328 }
 329
 330 static void pkcs1pad_decrypt_complete_cb(
 331                 struct crypto_async_request *child_async_req, int err)
 332 {
 333         struct akcipher_request *req = child_async_req->data;
 334         struct crypto_async_request async_req;
 335
 336         if (err == -EINPROGRESS)
 337                 return;
 338
 339         async_req.data = req->base.data;
 340         async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
 341         async_req.flags = child_async_req->flags;
 342         req->base.complete(&async_req, pkcs1pad_decrypt_complete(req, err));
 343 }
 344
 345 static int pkcs1pad_decrypt(struct akcipher_request *req)
 346 {
 347         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 348         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 349         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 350         int err;
 351
 352         if (!ctx->key_size || req->src_len != ctx->key_size)
 353                 return -EINVAL;
 354
 355         req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
 356         if (!req_ctx->out_buf)
 357                 return -ENOMEM;
 358
 359         pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
 360                             ctx->key_size, NULL);
 361
 362         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 363         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 364                         pkcs1pad_decrypt_complete_cb, req);
 365
 366         /* Reuse input buffer, output to a new buffer */
 367         akcipher_request_set_crypt(&req_ctx->child_req, req->src,
 368                                    req_ctx->out_sg, req->src_len,
 369                                    ctx->key_size);
 370
 371         err = crypto_akcipher_decrypt(&req_ctx->child_req);
 372         if (err != -EINPROGRESS && err != -EBUSY)
 373                 return pkcs1pad_decrypt_complete(req, err);
 374
 375         return err;
 376 }
 377
 378 static int pkcs1pad_sign(struct akcipher_request *req)
 379 {
 380         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 381         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 382         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 383         struct akcipher_instance *inst = akcipher_alg_instance(tfm);
 384         struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
 385         const struct rsa_asn1_template *digest_info = ictx->digest_info;
 386         int err;
 387         unsigned int ps_end, digest_size = 0;
 388
 389         if (!ctx->key_size)
 390                 return -EINVAL;
 391
 392         if (digest_info)
 393                 digest_size = digest_info->size;
 394
 395         if (req->src_len + digest_size > ctx->key_size - 11)
 396                 return -EOVERFLOW;
 397
 398         if (req->dst_len < ctx->key_size) {
 399                 req->dst_len = ctx->key_size;
 400                 return -EOVERFLOW;
 401         }
 402
 403         req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
 404                                   GFP_KERNEL);
 405         if (!req_ctx->in_buf)
 406                 return -ENOMEM;
 407
 408         ps_end = ctx->key_size - digest_size - req->src_len - 2;
 409         req_ctx->in_buf[0] = 0x01;
 410         memset(req_ctx->in_buf + 1, 0xff, ps_end - 1);
 411         req_ctx->in_buf[ps_end] = 0x00;
 412
 413         if (digest_info)
 414                 memcpy(req_ctx->in_buf + ps_end + 1, digest_info->data,
 415                        digest_info->size);
 416
 417         pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
 418                         ctx->key_size - 1 - req->src_len, req->src);
 419
 420         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 421         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 422                         pkcs1pad_encrypt_sign_complete_cb, req);
 423
 424         /* Reuse output buffer */
 425         akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
 426                                    req->dst, ctx->key_size - 1, req->dst_len);
 427
 428         err = crypto_akcipher_decrypt(&req_ctx->child_req);
 429         if (err != -EINPROGRESS && err != -EBUSY)
 430                 return pkcs1pad_encrypt_sign_complete(req, err);
 431
 432         return err;
 433 }
 434
 435 static int pkcs1pad_verify_complete(struct akcipher_request *req, int err)
 436 {
 437         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 438         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 439         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 440         struct akcipher_instance *inst = akcipher_alg_instance(tfm);
 441         struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
 442         const struct rsa_asn1_template *digest_info = ictx->digest_info;
 443         unsigned int dst_len;
 444         unsigned int pos;
 445         u8 *out_buf;
 446
 447         if (err)
 448                 goto done;
 449
 450         err = -EINVAL;
 451         dst_len = req_ctx->child_req.dst_len;
 452         if (dst_len < ctx->key_size - 1)
 453                 goto done;
 454
 455         out_buf = req_ctx->out_buf;
 456         if (dst_len == ctx->key_size) {
 457                 if (out_buf[0] != 0x00)
 458                         /* Decrypted value had no leading 0 byte */
 459                         goto done;
 460
 461                 dst_len--;
 462                 out_buf++;
 463         }
 464
 465         err = -EBADMSG;
 466         if (out_buf[0] != 0x01)
 467                 goto done;
 468
 469         for (pos = 1; pos < dst_len; pos++)
 470                 if (out_buf[pos] != 0xff)
 471                         break;
 472
 473         if (pos < 9 || pos == dst_len || out_buf[pos] != 0x00)
 474                 goto done;
 475         pos++;
 476
 477         if (digest_info) {
 478                 if (crypto_memneq(out_buf + pos, digest_info->data,
 479                                   digest_info->size))
 480                         goto done;
 481
 482                 pos += digest_info->size;
 483         }
 484
 485         err = 0;
 486
 487         if (req->dst_len != dst_len - pos) {
 488                 err = -EKEYREJECTED;
 489                 req->dst_len = dst_len - pos;
 490                 goto done;
 491         }
 492         /* Extract appended digest. */
 493         sg_pcopy_to_buffer(req->src,
 494                            sg_nents_for_len(req->src,
 495                                             req->src_len + req->dst_len),
 496                            req_ctx->out_buf + ctx->key_size,
 497                            req->dst_len, ctx->key_size);
 498         /* Do the actual verification step. */
 499         if (memcmp(req_ctx->out_buf + ctx->key_size, out_buf + pos,
 500                    req->dst_len) != 0)
 501                 err = -EKEYREJECTED;
 502 done:
 503         kzfree(req_ctx->out_buf);
 504
 505         return err;
 506 }
 507
 508 static void pkcs1pad_verify_complete_cb(
 509                 struct crypto_async_request *child_async_req, int err)
 510 {
 511         struct akcipher_request *req = child_async_req->data;
 512         struct crypto_async_request async_req;
 513
 514         if (err == -EINPROGRESS)
 515                 return;
 516
 517         async_req.data = req->base.data;
 518         async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
 519         async_req.flags = child_async_req->flags;
 520         req->base.complete(&async_req, pkcs1pad_verify_complete(req, err));
 521 }
 522
 523 /*
 524  * The verify operation is here for completeness similar to the verification
 525  * defined in RFC2313 section 10.2 except that block type 0 is not accepted,
 526  * as in RFC2437.  RFC2437 section 9.2 doesn't define any operation to
 527  * retrieve the DigestInfo from a signature, instead the user is expected
 528  * to call the sign operation to generate the expected signature and compare
 529  * signatures instead of the message-digests.
 530  */
 531 static int pkcs1pad_verify(struct akcipher_request *req)
 532 {
 533         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 534         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 535         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 536         int err;
 537
 538         if (WARN_ON(req->dst) ||
 539             WARN_ON(!req->dst_len) ||
 540             !ctx->key_size || req->src_len < ctx->key_size)
 541                 return -EINVAL;
 542
 543         req_ctx->out_buf = kmalloc(ctx->key_size + req->dst_len, GFP_KERNEL);
 544         if (!req_ctx->out_buf)
 545                 return -ENOMEM;
 546
 547         pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
 548                             ctx->key_size, NULL);
 549
 550         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 551         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 552                         pkcs1pad_verify_complete_cb, req);
 553
 554         /* Reuse input buffer, output to a new buffer */
 555         akcipher_request_set_crypt(&req_ctx->child_req, req->src,
 556                                    req_ctx->out_sg, req->src_len,
 557                                    ctx->key_size);
 558
 559         err = crypto_akcipher_encrypt(&req_ctx->child_req);
 560         if (err != -EINPROGRESS && err != -EBUSY)
 561                 return pkcs1pad_verify_complete(req, err);
 562
 563         return err;
 564 }
 565
 566 static int pkcs1pad_init_tfm(struct crypto_akcipher *tfm)
 567 {
 568         struct akcipher_instance *inst = akcipher_alg_instance(tfm);
 569         struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
 570         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 571         struct crypto_akcipher *child_tfm;
 572
 573         child_tfm = crypto_spawn_akcipher(&ictx->spawn);
 574         if (IS_ERR(child_tfm))
 575                 return PTR_ERR(child_tfm);
 576
 577         ctx->child = child_tfm;
 578         return 0;
 579 }
 580
 581 static void pkcs1pad_exit_tfm(struct crypto_akcipher *tfm)
 582 {
 583         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 584
 585         crypto_free_akcipher(ctx->child);
 586 }
 587
 588 static void pkcs1pad_free(struct akcipher_instance *inst)
 589 {
 590         struct pkcs1pad_inst_ctx *ctx = akcipher_instance_ctx(inst);
 591         struct crypto_akcipher_spawn *spawn = &ctx->spawn;
 592
 593         crypto_drop_akcipher(spawn);
 594         kfree(inst);
 595 }
 596
 597 static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)
 598 {
 599         const struct rsa_asn1_template *digest_info;
 600         struct crypto_attr_type *algt;
 601         u32 mask;
 602         struct akcipher_instance *inst;
 603         struct pkcs1pad_inst_ctx *ctx;
 604         struct crypto_akcipher_spawn *spawn;
 605         struct akcipher_alg *rsa_alg;
 606         const char *rsa_alg_name;
 607         const char *hash_name;
 608         int err;
 609
 610         algt = crypto_get_attr_type(tb);
 611         if (IS_ERR(algt))
 612                 return PTR_ERR(algt);
 613
 614         if ((algt->type ^ CRYPTO_ALG_TYPE_AKCIPHER) & algt->mask)
 615                 return -EINVAL;
 616
 617         mask = crypto_requires_sync(algt->type, algt->mask);
 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                 hash_name = NULL;
 626
 627         if (hash_name) {
 628                 digest_info = rsa_lookup_asn1(hash_name);
 629                 if (!digest_info)
 630                         return -EINVAL;
 631         } else
 632                 digest_info = NULL;
 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         err = crypto_grab_akcipher(spawn, akcipher_crypto_instance(inst),
 643                                    rsa_alg_name, 0, 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 (!hash_name) {
 652                 if (snprintf(inst->alg.base.cra_name,
 653                              CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)",
 654                              rsa_alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
 655                         goto out_drop_alg;
 656
 657                 if (snprintf(inst->alg.base.cra_driver_name,
 658                              CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)",
 659                              rsa_alg->base.cra_driver_name) >=
 660                              CRYPTO_MAX_ALG_NAME)
 661                         goto out_drop_alg;
 662         } else {
 663                 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
 664                              "pkcs1pad(%s,%s)", rsa_alg->base.cra_name,
 665                              hash_name) >= CRYPTO_MAX_ALG_NAME)
 666                         goto out_drop_alg;
 667
 668                 if (snprintf(inst->alg.base.cra_driver_name,
 669                              CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s,%s)",
 670                              rsa_alg->base.cra_driver_name,
 671                              hash_name) >= CRYPTO_MAX_ALG_NAME)
 672                         goto out_drop_alg;
 673         }
 674
 675         inst->alg.base.cra_flags = rsa_alg->base.cra_flags & CRYPTO_ALG_ASYNC;
 676         inst->alg.base.cra_priority = rsa_alg->base.cra_priority;
 677         inst->alg.base.cra_ctxsize = sizeof(struct pkcs1pad_ctx);
 678
 679         inst->alg.init = pkcs1pad_init_tfm;
 680         inst->alg.exit = pkcs1pad_exit_tfm;
 681
 682         inst->alg.encrypt = pkcs1pad_encrypt;
 683         inst->alg.decrypt = pkcs1pad_decrypt;
 684         inst->alg.sign = pkcs1pad_sign;
 685         inst->alg.verify = pkcs1pad_verify;
 686         inst->alg.set_pub_key = pkcs1pad_set_pub_key;
 687         inst->alg.set_priv_key = pkcs1pad_set_priv_key;
 688         inst->alg.max_size = pkcs1pad_get_max_size;
 689         inst->alg.reqsize = sizeof(struct pkcs1pad_request) + rsa_alg->reqsize;
 690
 691         inst->free = pkcs1pad_free;
 692
 693         err = akcipher_register_instance(tmpl, inst);
 694         if (err)
 695                 goto out_drop_alg;
 696
 697         return 0;
 698
 699 out_drop_alg:
 700         crypto_drop_akcipher(spawn);
 701 out_free_inst:
 702         kfree(inst);
 703         return err;
 704 }
 705
 706 struct crypto_template rsa_pkcs1pad_tmpl = {
 707         .name = "pkcs1pad",
 708         .create = pkcs1pad_create,
 709         .module = THIS_MODULE,
 710 };