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 #include <linux/scatterlist.h>
  18
  19 /*
  20  * Hash algorithm OIDs plus ASN.1 DER wrappings [RFC4880 sec 5.2.2].
  21  */
  22 static const u8 rsa_digest_info_md5[] = {
  23         0x30, 0x20, 0x30, 0x0c, 0x06, 0x08,
  24         0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x02, 0x05, /* OID */
  25         0x05, 0x00, 0x04, 0x10
  26 };
  27
  28 static const u8 rsa_digest_info_sha1[] = {
  29         0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
  30         0x2b, 0x0e, 0x03, 0x02, 0x1a,
  31         0x05, 0x00, 0x04, 0x14
  32 };
  33
  34 static const u8 rsa_digest_info_rmd160[] = {
  35         0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
  36         0x2b, 0x24, 0x03, 0x02, 0x01,
  37         0x05, 0x00, 0x04, 0x14
  38 };
  39
  40 static const u8 rsa_digest_info_sha224[] = {
  41         0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09,
  42         0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04,
  43         0x05, 0x00, 0x04, 0x1c
  44 };
  45
  46 static const u8 rsa_digest_info_sha256[] = {
  47         0x30, 0x31, 0x30, 0x0d, 0x06, 0x09,
  48         0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01,
  49         0x05, 0x00, 0x04, 0x20
  50 };
  51
  52 static const u8 rsa_digest_info_sha384[] = {
  53         0x30, 0x41, 0x30, 0x0d, 0x06, 0x09,
  54         0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02,
  55         0x05, 0x00, 0x04, 0x30
  56 };
  57
  58 static const u8 rsa_digest_info_sha512[] = {
  59         0x30, 0x51, 0x30, 0x0d, 0x06, 0x09,
  60         0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03,
  61         0x05, 0x00, 0x04, 0x40
  62 };
  63
  64 static const struct rsa_asn1_template {
  65         const char      *name;
  66         const u8        *data;
  67         size_t          size;
  68 } rsa_asn1_templates[] = {
  69 #define _(X) { #X, rsa_digest_info_##X, sizeof(rsa_digest_info_##X) }
  70         _(md5),
  71         _(sha1),
  72         _(rmd160),
  73         _(sha256),
  74         _(sha384),
  75         _(sha512),
  76         _(sha224),
  77         { NULL }
  78 #undef _
  79 };
  80
  81 static const struct rsa_asn1_template *rsa_lookup_asn1(const char *name)
  82 {
  83         const struct rsa_asn1_template *p;
  84
  85         for (p = rsa_asn1_templates; p->name; p++)
  86                 if (strcmp(name, p->name) == 0)
  87                         return p;
  88         return NULL;
  89 }
  90
  91 struct pkcs1pad_ctx {
  92         struct crypto_akcipher *child;
  93         unsigned int key_size;
  94 };
  95
  96 struct pkcs1pad_inst_ctx {
  97         struct crypto_akcipher_spawn spawn;
  98         const struct rsa_asn1_template *digest_info;
  99 };
 100
 101 struct pkcs1pad_request {
 102         struct scatterlist in_sg[2], out_sg[1];
 103         uint8_t *in_buf, *out_buf;
 104         struct akcipher_request child_req;
 105 };
 106
 107 static int pkcs1pad_set_pub_key(struct crypto_akcipher *tfm, const void *key,
 108                 unsigned int keylen)
 109 {
 110         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 111         int err;
 112
 113         ctx->key_size = 0;
 114
 115         err = crypto_akcipher_set_pub_key(ctx->child, key, keylen);
 116         if (err)
 117                 return err;
 118
 119         /* Find out new modulus size from rsa implementation */
 120         err = crypto_akcipher_maxsize(ctx->child);
 121         if (err > PAGE_SIZE)
 122                 return -ENOTSUPP;
 123
 124         ctx->key_size = err;
 125         return 0;
 126 }
 127
 128 static int pkcs1pad_set_priv_key(struct crypto_akcipher *tfm, const void *key,
 129                 unsigned int keylen)
 130 {
 131         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 132         int err;
 133
 134         ctx->key_size = 0;
 135
 136         err = crypto_akcipher_set_priv_key(ctx->child, key, keylen);
 137         if (err)
 138                 return err;
 139
 140         /* Find out new modulus size from rsa implementation */
 141         err = crypto_akcipher_maxsize(ctx->child);
 142         if (err > PAGE_SIZE)
 143                 return -ENOTSUPP;
 144
 145         ctx->key_size = err;
 146         return 0;
 147 }
 148
 149 static unsigned int pkcs1pad_get_max_size(struct crypto_akcipher *tfm)
 150 {
 151         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 152
 153         /*
 154          * The maximum destination buffer size for the encrypt/sign operations
 155          * will be the same as for RSA, even though it's smaller for
 156          * decrypt/verify.
 157          */
 158
 159         return ctx->key_size;
 160 }
 161
 162 static void pkcs1pad_sg_set_buf(struct scatterlist *sg, void *buf, size_t len,
 163                 struct scatterlist *next)
 164 {
 165         int nsegs = next ? 2 : 1;
 166
 167         sg_init_table(sg, nsegs);
 168         sg_set_buf(sg, buf, len);
 169
 170         if (next)
 171                 sg_chain(sg, nsegs, next);
 172 }
 173
 174 static int pkcs1pad_encrypt_sign_complete(struct akcipher_request *req, int err)
 175 {
 176         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 177         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 178         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 179         unsigned int pad_len;
 180         unsigned int len;
 181         u8 *out_buf;
 182
 183         if (err)
 184                 goto out;
 185
 186         len = req_ctx->child_req.dst_len;
 187         pad_len = ctx->key_size - len;
 188
 189         /* Four billion to one */
 190         if (likely(!pad_len))
 191                 goto out;
 192
 193         out_buf = kzalloc(ctx->key_size, GFP_KERNEL);
 194         err = -ENOMEM;
 195         if (!out_buf)
 196                 goto out;
 197
 198         sg_copy_to_buffer(req->dst, sg_nents_for_len(req->dst, len),
 199                           out_buf + pad_len, len);
 200         sg_copy_from_buffer(req->dst,
 201                             sg_nents_for_len(req->dst, ctx->key_size),
 202                             out_buf, ctx->key_size);
 203         kfree_sensitive(out_buf);
 204
 205 out:
 206         req->dst_len = ctx->key_size;
 207
 208         kfree(req_ctx->in_buf);
 209
 210         return err;
 211 }
 212
 213 static void pkcs1pad_encrypt_sign_complete_cb(
 214                 struct crypto_async_request *child_async_req, int err)
 215 {
 216         struct akcipher_request *req = child_async_req->data;
 217         struct crypto_async_request async_req;
 218
 219         if (err == -EINPROGRESS)
 220                 return;
 221
 222         async_req.data = req->base.data;
 223         async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
 224         async_req.flags = child_async_req->flags;
 225         req->base.complete(&async_req,
 226                         pkcs1pad_encrypt_sign_complete(req, err));
 227 }
 228
 229 static int pkcs1pad_encrypt(struct akcipher_request *req)
 230 {
 231         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 232         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 233         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 234         int err;
 235         unsigned int i, ps_end;
 236
 237         if (!ctx->key_size)
 238                 return -EINVAL;
 239
 240         if (req->src_len > ctx->key_size - 11)
 241                 return -EOVERFLOW;
 242
 243         if (req->dst_len < ctx->key_size) {
 244                 req->dst_len = ctx->key_size;
 245                 return -EOVERFLOW;
 246         }
 247
 248         req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
 249                                   GFP_KERNEL);
 250         if (!req_ctx->in_buf)
 251                 return -ENOMEM;
 252
 253         ps_end = ctx->key_size - req->src_len - 2;
 254         req_ctx->in_buf[0] = 0x02;
 255         for (i = 1; i < ps_end; i++)
 256                 req_ctx->in_buf[i] = 1 + prandom_u32_max(255);
 257         req_ctx->in_buf[ps_end] = 0x00;
 258
 259         pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
 260                         ctx->key_size - 1 - req->src_len, req->src);
 261
 262         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 263         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 264                         pkcs1pad_encrypt_sign_complete_cb, req);
 265
 266         /* Reuse output buffer */
 267         akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
 268                                    req->dst, ctx->key_size - 1, req->dst_len);
 269
 270         err = crypto_akcipher_encrypt(&req_ctx->child_req);
 271         if (err != -EINPROGRESS && err != -EBUSY)
 272                 return pkcs1pad_encrypt_sign_complete(req, err);
 273
 274         return err;
 275 }
 276
 277 static int pkcs1pad_decrypt_complete(struct akcipher_request *req, int err)
 278 {
 279         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 280         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 281         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 282         unsigned int dst_len;
 283         unsigned int pos;
 284         u8 *out_buf;
 285
 286         if (err)
 287                 goto done;
 288
 289         err = -EINVAL;
 290         dst_len = req_ctx->child_req.dst_len;
 291         if (dst_len < ctx->key_size - 1)
 292                 goto done;
 293
 294         out_buf = req_ctx->out_buf;
 295         if (dst_len == ctx->key_size) {
 296                 if (out_buf[0] != 0x00)
 297                         /* Decrypted value had no leading 0 byte */
 298                         goto done;
 299
 300                 dst_len--;
 301                 out_buf++;
 302         }
 303
 304         if (out_buf[0] != 0x02)
 305                 goto done;
 306
 307         for (pos = 1; pos < dst_len; pos++)
 308                 if (out_buf[pos] == 0x00)
 309                         break;
 310         if (pos < 9 || pos == dst_len)
 311                 goto done;
 312         pos++;
 313
 314         err = 0;
 315
 316         if (req->dst_len < dst_len - pos)
 317                 err = -EOVERFLOW;
 318         req->dst_len = dst_len - pos;
 319
 320         if (!err)
 321                 sg_copy_from_buffer(req->dst,
 322                                 sg_nents_for_len(req->dst, req->dst_len),
 323                                 out_buf + pos, req->dst_len);
 324
 325 done:
 326         kfree_sensitive(req_ctx->out_buf);
 327
 328         return err;
 329 }
 330
 331 static void pkcs1pad_decrypt_complete_cb(
 332                 struct crypto_async_request *child_async_req, int err)
 333 {
 334         struct akcipher_request *req = child_async_req->data;
 335         struct crypto_async_request async_req;
 336
 337         if (err == -EINPROGRESS)
 338                 return;
 339
 340         async_req.data = req->base.data;
 341         async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
 342         async_req.flags = child_async_req->flags;
 343         req->base.complete(&async_req, pkcs1pad_decrypt_complete(req, err));
 344 }
 345
 346 static int pkcs1pad_decrypt(struct akcipher_request *req)
 347 {
 348         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 349         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 350         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 351         int err;
 352
 353         if (!ctx->key_size || req->src_len != ctx->key_size)
 354                 return -EINVAL;
 355
 356         req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
 357         if (!req_ctx->out_buf)
 358                 return -ENOMEM;
 359
 360         pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
 361                             ctx->key_size, NULL);
 362
 363         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 364         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 365                         pkcs1pad_decrypt_complete_cb, req);
 366
 367         /* Reuse input buffer, output to a new buffer */
 368         akcipher_request_set_crypt(&req_ctx->child_req, req->src,
 369                                    req_ctx->out_sg, req->src_len,
 370                                    ctx->key_size);
 371
 372         err = crypto_akcipher_decrypt(&req_ctx->child_req);
 373         if (err != -EINPROGRESS && err != -EBUSY)
 374                 return pkcs1pad_decrypt_complete(req, err);
 375
 376         return err;
 377 }
 378
 379 static int pkcs1pad_sign(struct akcipher_request *req)
 380 {
 381         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 382         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 383         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 384         struct akcipher_instance *inst = akcipher_alg_instance(tfm);
 385         struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
 386         const struct rsa_asn1_template *digest_info = ictx->digest_info;
 387         int err;
 388         unsigned int ps_end, digest_size = 0;
 389
 390         if (!ctx->key_size)
 391                 return -EINVAL;
 392
 393         if (digest_info)
 394                 digest_size = digest_info->size;
 395
 396         if (req->src_len + digest_size > ctx->key_size - 11)
 397                 return -EOVERFLOW;
 398
 399         if (req->dst_len < ctx->key_size) {
 400                 req->dst_len = ctx->key_size;
 401                 return -EOVERFLOW;
 402         }
 403
 404         req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
 405                                   GFP_KERNEL);
 406         if (!req_ctx->in_buf)
 407                 return -ENOMEM;
 408
 409         ps_end = ctx->key_size - digest_size - req->src_len - 2;
 410         req_ctx->in_buf[0] = 0x01;
 411         memset(req_ctx->in_buf + 1, 0xff, ps_end - 1);
 412         req_ctx->in_buf[ps_end] = 0x00;
 413
 414         if (digest_info)
 415                 memcpy(req_ctx->in_buf + ps_end + 1, digest_info->data,
 416                        digest_info->size);
 417
 418         pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
 419                         ctx->key_size - 1 - req->src_len, req->src);
 420
 421         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 422         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 423                         pkcs1pad_encrypt_sign_complete_cb, req);
 424
 425         /* Reuse output buffer */
 426         akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
 427                                    req->dst, ctx->key_size - 1, req->dst_len);
 428
 429         err = crypto_akcipher_decrypt(&req_ctx->child_req);
 430         if (err != -EINPROGRESS && err != -EBUSY)
 431                 return pkcs1pad_encrypt_sign_complete(req, err);
 432
 433         return err;
 434 }
 435
 436 static int pkcs1pad_verify_complete(struct akcipher_request *req, int err)
 437 {
 438         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 439         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 440         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 441         struct akcipher_instance *inst = akcipher_alg_instance(tfm);
 442         struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
 443         const struct rsa_asn1_template *digest_info = ictx->digest_info;
 444         unsigned int dst_len;
 445         unsigned int pos;
 446         u8 *out_buf;
 447
 448         if (err)
 449                 goto done;
 450
 451         err = -EINVAL;
 452         dst_len = req_ctx->child_req.dst_len;
 453         if (dst_len < ctx->key_size - 1)
 454                 goto done;
 455
 456         out_buf = req_ctx->out_buf;
 457         if (dst_len == ctx->key_size) {
 458                 if (out_buf[0] != 0x00)
 459                         /* Decrypted value had no leading 0 byte */
 460                         goto done;
 461
 462                 dst_len--;
 463                 out_buf++;
 464         }
 465
 466         err = -EBADMSG;
 467         if (out_buf[0] != 0x01)
 468                 goto done;
 469
 470         for (pos = 1; pos < dst_len; pos++)
 471                 if (out_buf[pos] != 0xff)
 472                         break;
 473
 474         if (pos < 9 || pos == dst_len || out_buf[pos] != 0x00)
 475                 goto done;
 476         pos++;
 477
 478         if (digest_info) {
 479                 if (digest_info->size > dst_len - pos)
 480                         goto done;
 481                 if (crypto_memneq(out_buf + pos, digest_info->data,
 482                                   digest_info->size))
 483                         goto done;
 484
 485                 pos += digest_info->size;
 486         }
 487
 488         err = 0;
 489
 490         if (req->dst_len != dst_len - pos) {
 491                 err = -EKEYREJECTED;
 492                 req->dst_len = dst_len - pos;
 493                 goto done;
 494         }
 495         /* Extract appended digest. */
 496         sg_pcopy_to_buffer(req->src,
 497                            sg_nents_for_len(req->src,
 498                                             req->src_len + req->dst_len),
 499                            req_ctx->out_buf + ctx->key_size,
 500                            req->dst_len, req->src_len);
 501         /* Do the actual verification step. */
 502         if (memcmp(req_ctx->out_buf + ctx->key_size, out_buf + pos,
 503                    req->dst_len) != 0)
 504                 err = -EKEYREJECTED;
 505 done:
 506         kfree_sensitive(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 (WARN_ON(req->dst) ||
 542             WARN_ON(!req->dst_len) ||
 543             !ctx->key_size || req->src_len != ctx->key_size)
 544                 return -EINVAL;
 545
 546         req_ctx->out_buf = kmalloc(ctx->key_size + req->dst_len, GFP_KERNEL);
 547         if (!req_ctx->out_buf)
 548                 return -ENOMEM;
 549
 550         pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
 551                             ctx->key_size, NULL);
 552
 553         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 554         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 555                         pkcs1pad_verify_complete_cb, req);
 556
 557         /* Reuse input buffer, output to a new buffer */
 558         akcipher_request_set_crypt(&req_ctx->child_req, req->src,
 559                                    req_ctx->out_sg, req->src_len,
 560                                    ctx->key_size);
 561
 562         err = crypto_akcipher_encrypt(&req_ctx->child_req);
 563         if (err != -EINPROGRESS && err != -EBUSY)
 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         u32 mask;
 603         struct akcipher_instance *inst;
 604         struct pkcs1pad_inst_ctx *ctx;
 605         struct akcipher_alg *rsa_alg;
 606         const char *hash_name;
 607         int err;
 608
 609         err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AKCIPHER, &mask);
 610         if (err)
 611                 return err;
 612
 613         inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
 614         if (!inst)
 615                 return -ENOMEM;
 616
 617         ctx = akcipher_instance_ctx(inst);
 618
 619         err = crypto_grab_akcipher(&ctx->spawn, akcipher_crypto_instance(inst),
 620                                    crypto_attr_alg_name(tb[1]), 0, mask);
 621         if (err)
 622                 goto err_free_inst;
 623
 624         rsa_alg = crypto_spawn_akcipher_alg(&ctx->spawn);
 625
 626         if (strcmp(rsa_alg->base.cra_name, "rsa") != 0) {
 627                 err = -EINVAL;
 628                 goto err_free_inst;
 629         }
 630
 631         err = -ENAMETOOLONG;
 632         hash_name = crypto_attr_alg_name(tb[2]);
 633         if (IS_ERR(hash_name)) {
 634                 if (snprintf(inst->alg.base.cra_name,
 635                              CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)",
 636                              rsa_alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
 637                         goto err_free_inst;
 638
 639                 if (snprintf(inst->alg.base.cra_driver_name,
 640                              CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)",
 641                              rsa_alg->base.cra_driver_name) >=
 642                              CRYPTO_MAX_ALG_NAME)
 643                         goto err_free_inst;
 644         } else {
 645                 ctx->digest_info = rsa_lookup_asn1(hash_name);
 646                 if (!ctx->digest_info) {
 647                         err = -EINVAL;
 648                         goto err_free_inst;
 649                 }
 650
 651                 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
 652                              "pkcs1pad(%s,%s)", rsa_alg->base.cra_name,
 653                              hash_name) >= CRYPTO_MAX_ALG_NAME)
 654                         goto err_free_inst;
 655
 656                 if (snprintf(inst->alg.base.cra_driver_name,
 657                              CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s,%s)",
 658                              rsa_alg->base.cra_driver_name,
 659                              hash_name) >= CRYPTO_MAX_ALG_NAME)
 660                         goto err_free_inst;
 661         }
 662
 663         inst->alg.base.cra_priority = rsa_alg->base.cra_priority;
 664         inst->alg.base.cra_ctxsize = sizeof(struct pkcs1pad_ctx);
 665
 666         inst->alg.init = pkcs1pad_init_tfm;
 667         inst->alg.exit = pkcs1pad_exit_tfm;
 668
 669         inst->alg.encrypt = pkcs1pad_encrypt;
 670         inst->alg.decrypt = pkcs1pad_decrypt;
 671         inst->alg.sign = pkcs1pad_sign;
 672         inst->alg.verify = pkcs1pad_verify;
 673         inst->alg.set_pub_key = pkcs1pad_set_pub_key;
 674         inst->alg.set_priv_key = pkcs1pad_set_priv_key;
 675         inst->alg.max_size = pkcs1pad_get_max_size;
 676         inst->alg.reqsize = sizeof(struct pkcs1pad_request) + rsa_alg->reqsize;
 677
 678         inst->free = pkcs1pad_free;
 679
 680         err = akcipher_register_instance(tmpl, inst);
 681         if (err) {
 682 err_free_inst:
 683                 pkcs1pad_free(inst);
 684         }
 685         return err;
 686 }
 687
 688 struct crypto_template rsa_pkcs1pad_tmpl = {
 689         .name = "pkcs1pad",
 690         .create = pkcs1pad_create,
 691         .module = THIS_MODULE,
 692 };