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_ATOMIC);
 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(void *data, int err)
 214 {
 215         struct akcipher_request *req = data;
 216
 217         if (err == -EINPROGRESS)
 218                 goto out;
 219
 220         err = pkcs1pad_encrypt_sign_complete(req, err);
 221
 222 out:
 223         akcipher_request_complete(req, err);
 224 }
 225
 226 static int pkcs1pad_encrypt(struct akcipher_request *req)
 227 {
 228         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 229         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 230         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 231         int err;
 232         unsigned int i, ps_end;
 233
 234         if (!ctx->key_size)
 235                 return -EINVAL;
 236
 237         if (req->src_len > ctx->key_size - 11)
 238                 return -EOVERFLOW;
 239
 240         if (req->dst_len < ctx->key_size) {
 241                 req->dst_len = ctx->key_size;
 242                 return -EOVERFLOW;
 243         }
 244
 245         req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
 246                                   GFP_KERNEL);
 247         if (!req_ctx->in_buf)
 248                 return -ENOMEM;
 249
 250         ps_end = ctx->key_size - req->src_len - 2;
 251         req_ctx->in_buf[0] = 0x02;
 252         for (i = 1; i < ps_end; i++)
 253                 req_ctx->in_buf[i] = get_random_u32_inclusive(1, 255);
 254         req_ctx->in_buf[ps_end] = 0x00;
 255
 256         pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
 257                         ctx->key_size - 1 - req->src_len, req->src);
 258
 259         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 260         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 261                         pkcs1pad_encrypt_sign_complete_cb, req);
 262
 263         /* Reuse output buffer */
 264         akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
 265                                    req->dst, ctx->key_size - 1, req->dst_len);
 266
 267         err = crypto_akcipher_encrypt(&req_ctx->child_req);
 268         if (err != -EINPROGRESS && err != -EBUSY)
 269                 return pkcs1pad_encrypt_sign_complete(req, err);
 270
 271         return err;
 272 }
 273
 274 static int pkcs1pad_decrypt_complete(struct akcipher_request *req, int err)
 275 {
 276         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 277         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 278         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 279         unsigned int dst_len;
 280         unsigned int pos;
 281         u8 *out_buf;
 282
 283         if (err)
 284                 goto done;
 285
 286         err = -EINVAL;
 287         dst_len = req_ctx->child_req.dst_len;
 288         if (dst_len < ctx->key_size - 1)
 289                 goto done;
 290
 291         out_buf = req_ctx->out_buf;
 292         if (dst_len == ctx->key_size) {
 293                 if (out_buf[0] != 0x00)
 294                         /* Decrypted value had no leading 0 byte */
 295                         goto done;
 296
 297                 dst_len--;
 298                 out_buf++;
 299         }
 300
 301         if (out_buf[0] != 0x02)
 302                 goto done;
 303
 304         for (pos = 1; pos < dst_len; pos++)
 305                 if (out_buf[pos] == 0x00)
 306                         break;
 307         if (pos < 9 || pos == dst_len)
 308                 goto done;
 309         pos++;
 310
 311         err = 0;
 312
 313         if (req->dst_len < dst_len - pos)
 314                 err = -EOVERFLOW;
 315         req->dst_len = dst_len - pos;
 316
 317         if (!err)
 318                 sg_copy_from_buffer(req->dst,
 319                                 sg_nents_for_len(req->dst, req->dst_len),
 320                                 out_buf + pos, req->dst_len);
 321
 322 done:
 323         kfree_sensitive(req_ctx->out_buf);
 324
 325         return err;
 326 }
 327
 328 static void pkcs1pad_decrypt_complete_cb(void *data, int err)
 329 {
 330         struct akcipher_request *req = data;
 331
 332         if (err == -EINPROGRESS)
 333                 goto out;
 334
 335         err = pkcs1pad_decrypt_complete(req, err);
 336
 337 out:
 338         akcipher_request_complete(req, err);
 339 }
 340
 341 static int pkcs1pad_decrypt(struct akcipher_request *req)
 342 {
 343         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 344         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 345         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 346         int err;
 347
 348         if (!ctx->key_size || req->src_len != ctx->key_size)
 349                 return -EINVAL;
 350
 351         req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
 352         if (!req_ctx->out_buf)
 353                 return -ENOMEM;
 354
 355         pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
 356                             ctx->key_size, NULL);
 357
 358         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 359         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 360                         pkcs1pad_decrypt_complete_cb, req);
 361
 362         /* Reuse input buffer, output to a new buffer */
 363         akcipher_request_set_crypt(&req_ctx->child_req, req->src,
 364                                    req_ctx->out_sg, req->src_len,
 365                                    ctx->key_size);
 366
 367         err = crypto_akcipher_decrypt(&req_ctx->child_req);
 368         if (err != -EINPROGRESS && err != -EBUSY)
 369                 return pkcs1pad_decrypt_complete(req, err);
 370
 371         return err;
 372 }
 373
 374 static int pkcs1pad_sign(struct akcipher_request *req)
 375 {
 376         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 377         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 378         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 379         struct akcipher_instance *inst = akcipher_alg_instance(tfm);
 380         struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
 381         const struct rsa_asn1_template *digest_info = ictx->digest_info;
 382         int err;
 383         unsigned int ps_end, digest_info_size = 0;
 384
 385         if (!ctx->key_size)
 386                 return -EINVAL;
 387
 388         if (digest_info)
 389                 digest_info_size = digest_info->size;
 390
 391         if (req->src_len + digest_info_size > ctx->key_size - 11)
 392                 return -EOVERFLOW;
 393
 394         if (req->dst_len < ctx->key_size) {
 395                 req->dst_len = ctx->key_size;
 396                 return -EOVERFLOW;
 397         }
 398
 399         req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
 400                                   GFP_KERNEL);
 401         if (!req_ctx->in_buf)
 402                 return -ENOMEM;
 403
 404         ps_end = ctx->key_size - digest_info_size - req->src_len - 2;
 405         req_ctx->in_buf[0] = 0x01;
 406         memset(req_ctx->in_buf + 1, 0xff, ps_end - 1);
 407         req_ctx->in_buf[ps_end] = 0x00;
 408
 409         if (digest_info)
 410                 memcpy(req_ctx->in_buf + ps_end + 1, digest_info->data,
 411                        digest_info->size);
 412
 413         pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
 414                         ctx->key_size - 1 - req->src_len, req->src);
 415
 416         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 417         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 418                         pkcs1pad_encrypt_sign_complete_cb, req);
 419
 420         /* Reuse output buffer */
 421         akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
 422                                    req->dst, ctx->key_size - 1, req->dst_len);
 423
 424         err = crypto_akcipher_decrypt(&req_ctx->child_req);
 425         if (err != -EINPROGRESS && err != -EBUSY)
 426                 return pkcs1pad_encrypt_sign_complete(req, err);
 427
 428         return err;
 429 }
 430
 431 static int pkcs1pad_verify_complete(struct akcipher_request *req, int err)
 432 {
 433         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 434         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 435         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 436         struct akcipher_instance *inst = akcipher_alg_instance(tfm);
 437         struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
 438         const struct rsa_asn1_template *digest_info = ictx->digest_info;
 439         const unsigned int sig_size = req->src_len;
 440         const unsigned int digest_size = req->dst_len;
 441         unsigned int dst_len;
 442         unsigned int pos;
 443         u8 *out_buf;
 444
 445         if (err)
 446                 goto done;
 447
 448         err = -EINVAL;
 449         dst_len = req_ctx->child_req.dst_len;
 450         if (dst_len < ctx->key_size - 1)
 451                 goto done;
 452
 453         out_buf = req_ctx->out_buf;
 454         if (dst_len == ctx->key_size) {
 455                 if (out_buf[0] != 0x00)
 456                         /* Decrypted value had no leading 0 byte */
 457                         goto done;
 458
 459                 dst_len--;
 460                 out_buf++;
 461         }
 462
 463         err = -EBADMSG;
 464         if (out_buf[0] != 0x01)
 465                 goto done;
 466
 467         for (pos = 1; pos < dst_len; pos++)
 468                 if (out_buf[pos] != 0xff)
 469                         break;
 470
 471         if (pos < 9 || pos == dst_len || out_buf[pos] != 0x00)
 472                 goto done;
 473         pos++;
 474
 475         if (digest_info) {
 476                 if (digest_info->size > dst_len - pos)
 477                         goto done;
 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 (digest_size != 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, sig_size + digest_size),
 495                            req_ctx->out_buf + ctx->key_size,
 496                            digest_size, sig_size);
 497         /* Do the actual verification step. */
 498         if (memcmp(req_ctx->out_buf + ctx->key_size, out_buf + pos,
 499                    digest_size) != 0)
 500                 err = -EKEYREJECTED;
 501 done:
 502         kfree_sensitive(req_ctx->out_buf);
 503
 504         return err;
 505 }
 506
 507 static void pkcs1pad_verify_complete_cb(void *data, int err)
 508 {
 509         struct akcipher_request *req = data;
 510
 511         if (err == -EINPROGRESS)
 512                 goto out;
 513
 514         err = pkcs1pad_verify_complete(req, err);
 515
 516 out:
 517         akcipher_request_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         const unsigned int sig_size = req->src_len;
 534         const unsigned int digest_size = req->dst_len;
 535         int err;
 536
 537         if (WARN_ON(req->dst) || WARN_ON(!digest_size) ||
 538             !ctx->key_size || sig_size != ctx->key_size)
 539                 return -EINVAL;
 540
 541         req_ctx->out_buf = kmalloc(ctx->key_size + digest_size, GFP_KERNEL);
 542         if (!req_ctx->out_buf)
 543                 return -ENOMEM;
 544
 545         pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
 546                             ctx->key_size, NULL);
 547
 548         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 549         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 550                         pkcs1pad_verify_complete_cb, req);
 551
 552         /* Reuse input buffer, output to a new buffer */
 553         akcipher_request_set_crypt(&req_ctx->child_req, req->src,
 554                                    req_ctx->out_sg, sig_size, ctx->key_size);
 555
 556         err = crypto_akcipher_encrypt(&req_ctx->child_req);
 557         if (err != -EINPROGRESS && err != -EBUSY)
 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
 576         akcipher_set_reqsize(tfm, sizeof(struct pkcs1pad_request) +
 577                                   crypto_akcipher_reqsize(child_tfm));
 578
 579         return 0;
 580 }
 581
 582 static void pkcs1pad_exit_tfm(struct crypto_akcipher *tfm)
 583 {
 584         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 585
 586         crypto_free_akcipher(ctx->child);
 587 }
 588
 589 static void pkcs1pad_free(struct akcipher_instance *inst)
 590 {
 591         struct pkcs1pad_inst_ctx *ctx = akcipher_instance_ctx(inst);
 592         struct crypto_akcipher_spawn *spawn = &ctx->spawn;
 593
 594         crypto_drop_akcipher(spawn);
 595         kfree(inst);
 596 }
 597
 598 static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)
 599 {
 600         u32 mask;
 601         struct akcipher_instance *inst;
 602         struct pkcs1pad_inst_ctx *ctx;
 603         struct akcipher_alg *rsa_alg;
 604         const char *hash_name;
 605         int err;
 606
 607         err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AKCIPHER, &mask);
 608         if (err)
 609                 return err;
 610
 611         inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
 612         if (!inst)
 613                 return -ENOMEM;
 614
 615         ctx = akcipher_instance_ctx(inst);
 616
 617         err = crypto_grab_akcipher(&ctx->spawn, akcipher_crypto_instance(inst),
 618                                    crypto_attr_alg_name(tb[1]), 0, mask);
 619         if (err)
 620                 goto err_free_inst;
 621
 622         rsa_alg = crypto_spawn_akcipher_alg(&ctx->spawn);
 623
 624         if (strcmp(rsa_alg->base.cra_name, "rsa") != 0) {
 625                 err = -EINVAL;
 626                 goto err_free_inst;
 627         }
 628
 629         err = -ENAMETOOLONG;
 630         hash_name = crypto_attr_alg_name(tb[2]);
 631         if (IS_ERR(hash_name)) {
 632                 if (snprintf(inst->alg.base.cra_name,
 633                              CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)",
 634                              rsa_alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
 635                         goto err_free_inst;
 636
 637                 if (snprintf(inst->alg.base.cra_driver_name,
 638                              CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)",
 639                              rsa_alg->base.cra_driver_name) >=
 640                              CRYPTO_MAX_ALG_NAME)
 641                         goto err_free_inst;
 642         } else {
 643                 ctx->digest_info = rsa_lookup_asn1(hash_name);
 644                 if (!ctx->digest_info) {
 645                         err = -EINVAL;
 646                         goto err_free_inst;
 647                 }
 648
 649                 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
 650                              "pkcs1pad(%s,%s)", rsa_alg->base.cra_name,
 651                              hash_name) >= CRYPTO_MAX_ALG_NAME)
 652                         goto err_free_inst;
 653
 654                 if (snprintf(inst->alg.base.cra_driver_name,
 655                              CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s,%s)",
 656                              rsa_alg->base.cra_driver_name,
 657                              hash_name) >= CRYPTO_MAX_ALG_NAME)
 658                         goto err_free_inst;
 659         }
 660
 661         inst->alg.base.cra_priority = rsa_alg->base.cra_priority;
 662         inst->alg.base.cra_ctxsize = sizeof(struct pkcs1pad_ctx);
 663
 664         inst->alg.init = pkcs1pad_init_tfm;
 665         inst->alg.exit = pkcs1pad_exit_tfm;
 666
 667         inst->alg.encrypt = pkcs1pad_encrypt;
 668         inst->alg.decrypt = pkcs1pad_decrypt;
 669         inst->alg.sign = pkcs1pad_sign;
 670         inst->alg.verify = pkcs1pad_verify;
 671         inst->alg.set_pub_key = pkcs1pad_set_pub_key;
 672         inst->alg.set_priv_key = pkcs1pad_set_priv_key;
 673         inst->alg.max_size = pkcs1pad_get_max_size;
 674
 675         inst->free = pkcs1pad_free;
 676
 677         err = akcipher_register_instance(tmpl, inst);
 678         if (err) {
 679 err_free_inst:
 680                 pkcs1pad_free(inst);
 681         }
 682         return err;
 683 }
 684
 685 struct crypto_template rsa_pkcs1pad_tmpl = {
 686         .name = "pkcs1pad",
 687         .create = pkcs1pad_create,
 688         .module = THIS_MODULE,
 689 };