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 u8 rsa_digest_info_sha3_256[] = {
  65         0x30, 0x31, 0x30, 0x0d, 0x06, 0x09,
  66         0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x08,
  67         0x05, 0x00, 0x04, 0x20
  68 };
  69
  70 static const u8 rsa_digest_info_sha3_384[] = {
  71         0x30, 0x41, 0x30, 0x0d, 0x06, 0x09,
  72         0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x09,
  73         0x05, 0x00, 0x04, 0x30
  74 };
  75
  76 static const u8 rsa_digest_info_sha3_512[] = {
  77         0x30, 0x51, 0x30, 0x0d, 0x06, 0x09,
  78         0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x0A,
  79         0x05, 0x00, 0x04, 0x40
  80 };
  81
  82 static const struct rsa_asn1_template {
  83         const char      *name;
  84         const u8        *data;
  85         size_t          size;
  86 } rsa_asn1_templates[] = {
  87 #define _(X) { #X, rsa_digest_info_##X, sizeof(rsa_digest_info_##X) }
  88         _(md5),
  89         _(sha1),
  90         _(rmd160),
  91         _(sha256),
  92         _(sha384),
  93         _(sha512),
  94         _(sha224),
  95 #undef _
  96 #define _(X) { "sha3-" #X, rsa_digest_info_sha3_##X, sizeof(rsa_digest_info_sha3_##X) }
  97         _(256),
  98         _(384),
  99         _(512),
 100 #undef _
 101         { NULL }
 102 };
 103
 104 static const struct rsa_asn1_template *rsa_lookup_asn1(const char *name)
 105 {
 106         const struct rsa_asn1_template *p;
 107
 108         for (p = rsa_asn1_templates; p->name; p++)
 109                 if (strcmp(name, p->name) == 0)
 110                         return p;
 111         return NULL;
 112 }
 113
 114 struct pkcs1pad_ctx {
 115         struct crypto_akcipher *child;
 116         unsigned int key_size;
 117 };
 118
 119 struct pkcs1pad_inst_ctx {
 120         struct crypto_akcipher_spawn spawn;
 121         const struct rsa_asn1_template *digest_info;
 122 };
 123
 124 struct pkcs1pad_request {
 125         struct scatterlist in_sg[2], out_sg[1];
 126         uint8_t *in_buf, *out_buf;
 127         struct akcipher_request child_req;
 128 };
 129
 130 static int pkcs1pad_set_pub_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_pub_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 int pkcs1pad_set_priv_key(struct crypto_akcipher *tfm, const void *key,
 152                 unsigned int keylen)
 153 {
 154         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 155         int err;
 156
 157         ctx->key_size = 0;
 158
 159         err = crypto_akcipher_set_priv_key(ctx->child, key, keylen);
 160         if (err)
 161                 return err;
 162
 163         /* Find out new modulus size from rsa implementation */
 164         err = crypto_akcipher_maxsize(ctx->child);
 165         if (err > PAGE_SIZE)
 166                 return -ENOTSUPP;
 167
 168         ctx->key_size = err;
 169         return 0;
 170 }
 171
 172 static unsigned int pkcs1pad_get_max_size(struct crypto_akcipher *tfm)
 173 {
 174         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 175
 176         /*
 177          * The maximum destination buffer size for the encrypt/sign operations
 178          * will be the same as for RSA, even though it's smaller for
 179          * decrypt/verify.
 180          */
 181
 182         return ctx->key_size;
 183 }
 184
 185 static void pkcs1pad_sg_set_buf(struct scatterlist *sg, void *buf, size_t len,
 186                 struct scatterlist *next)
 187 {
 188         int nsegs = next ? 2 : 1;
 189
 190         sg_init_table(sg, nsegs);
 191         sg_set_buf(sg, buf, len);
 192
 193         if (next)
 194                 sg_chain(sg, nsegs, next);
 195 }
 196
 197 static int pkcs1pad_encrypt_sign_complete(struct akcipher_request *req, int err)
 198 {
 199         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 200         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 201         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 202         unsigned int pad_len;
 203         unsigned int len;
 204         u8 *out_buf;
 205
 206         if (err)
 207                 goto out;
 208
 209         len = req_ctx->child_req.dst_len;
 210         pad_len = ctx->key_size - len;
 211
 212         /* Four billion to one */
 213         if (likely(!pad_len))
 214                 goto out;
 215
 216         out_buf = kzalloc(ctx->key_size, GFP_ATOMIC);
 217         err = -ENOMEM;
 218         if (!out_buf)
 219                 goto out;
 220
 221         sg_copy_to_buffer(req->dst, sg_nents_for_len(req->dst, len),
 222                           out_buf + pad_len, len);
 223         sg_copy_from_buffer(req->dst,
 224                             sg_nents_for_len(req->dst, ctx->key_size),
 225                             out_buf, ctx->key_size);
 226         kfree_sensitive(out_buf);
 227
 228 out:
 229         req->dst_len = ctx->key_size;
 230
 231         kfree(req_ctx->in_buf);
 232
 233         return err;
 234 }
 235
 236 static void pkcs1pad_encrypt_sign_complete_cb(void *data, int err)
 237 {
 238         struct akcipher_request *req = data;
 239
 240         if (err == -EINPROGRESS)
 241                 goto out;
 242
 243         err = pkcs1pad_encrypt_sign_complete(req, err);
 244
 245 out:
 246         akcipher_request_complete(req, err);
 247 }
 248
 249 static int pkcs1pad_encrypt(struct akcipher_request *req)
 250 {
 251         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 252         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 253         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 254         int err;
 255         unsigned int i, ps_end;
 256
 257         if (!ctx->key_size)
 258                 return -EINVAL;
 259
 260         if (req->src_len > ctx->key_size - 11)
 261                 return -EOVERFLOW;
 262
 263         if (req->dst_len < ctx->key_size) {
 264                 req->dst_len = ctx->key_size;
 265                 return -EOVERFLOW;
 266         }
 267
 268         req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
 269                                   GFP_KERNEL);
 270         if (!req_ctx->in_buf)
 271                 return -ENOMEM;
 272
 273         ps_end = ctx->key_size - req->src_len - 2;
 274         req_ctx->in_buf[0] = 0x02;
 275         for (i = 1; i < ps_end; i++)
 276                 req_ctx->in_buf[i] = get_random_u32_inclusive(1, 255);
 277         req_ctx->in_buf[ps_end] = 0x00;
 278
 279         pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
 280                         ctx->key_size - 1 - req->src_len, req->src);
 281
 282         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 283         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 284                         pkcs1pad_encrypt_sign_complete_cb, req);
 285
 286         /* Reuse output buffer */
 287         akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
 288                                    req->dst, ctx->key_size - 1, req->dst_len);
 289
 290         err = crypto_akcipher_encrypt(&req_ctx->child_req);
 291         if (err != -EINPROGRESS && err != -EBUSY)
 292                 return pkcs1pad_encrypt_sign_complete(req, err);
 293
 294         return err;
 295 }
 296
 297 static int pkcs1pad_decrypt_complete(struct akcipher_request *req, int err)
 298 {
 299         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 300         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 301         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 302         unsigned int dst_len;
 303         unsigned int pos;
 304         u8 *out_buf;
 305
 306         if (err)
 307                 goto done;
 308
 309         err = -EINVAL;
 310         dst_len = req_ctx->child_req.dst_len;
 311         if (dst_len < ctx->key_size - 1)
 312                 goto done;
 313
 314         out_buf = req_ctx->out_buf;
 315         if (dst_len == ctx->key_size) {
 316                 if (out_buf[0] != 0x00)
 317                         /* Decrypted value had no leading 0 byte */
 318                         goto done;
 319
 320                 dst_len--;
 321                 out_buf++;
 322         }
 323
 324         if (out_buf[0] != 0x02)
 325                 goto done;
 326
 327         for (pos = 1; pos < dst_len; pos++)
 328                 if (out_buf[pos] == 0x00)
 329                         break;
 330         if (pos < 9 || pos == dst_len)
 331                 goto done;
 332         pos++;
 333
 334         err = 0;
 335
 336         if (req->dst_len < dst_len - pos)
 337                 err = -EOVERFLOW;
 338         req->dst_len = dst_len - pos;
 339
 340         if (!err)
 341                 sg_copy_from_buffer(req->dst,
 342                                 sg_nents_for_len(req->dst, req->dst_len),
 343                                 out_buf + pos, req->dst_len);
 344
 345 done:
 346         kfree_sensitive(req_ctx->out_buf);
 347
 348         return err;
 349 }
 350
 351 static void pkcs1pad_decrypt_complete_cb(void *data, int err)
 352 {
 353         struct akcipher_request *req = data;
 354
 355         if (err == -EINPROGRESS)
 356                 goto out;
 357
 358         err = pkcs1pad_decrypt_complete(req, err);
 359
 360 out:
 361         akcipher_request_complete(req, err);
 362 }
 363
 364 static int pkcs1pad_decrypt(struct akcipher_request *req)
 365 {
 366         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 367         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 368         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 369         int err;
 370
 371         if (!ctx->key_size || req->src_len != ctx->key_size)
 372                 return -EINVAL;
 373
 374         req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
 375         if (!req_ctx->out_buf)
 376                 return -ENOMEM;
 377
 378         pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
 379                             ctx->key_size, NULL);
 380
 381         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 382         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 383                         pkcs1pad_decrypt_complete_cb, req);
 384
 385         /* Reuse input buffer, output to a new buffer */
 386         akcipher_request_set_crypt(&req_ctx->child_req, req->src,
 387                                    req_ctx->out_sg, req->src_len,
 388                                    ctx->key_size);
 389
 390         err = crypto_akcipher_decrypt(&req_ctx->child_req);
 391         if (err != -EINPROGRESS && err != -EBUSY)
 392                 return pkcs1pad_decrypt_complete(req, err);
 393
 394         return err;
 395 }
 396
 397 static int pkcs1pad_sign(struct akcipher_request *req)
 398 {
 399         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 400         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 401         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 402         struct akcipher_instance *inst = akcipher_alg_instance(tfm);
 403         struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
 404         const struct rsa_asn1_template *digest_info = ictx->digest_info;
 405         int err;
 406         unsigned int ps_end, digest_info_size = 0;
 407
 408         if (!ctx->key_size)
 409                 return -EINVAL;
 410
 411         if (digest_info)
 412                 digest_info_size = digest_info->size;
 413
 414         if (req->src_len + digest_info_size > ctx->key_size - 11)
 415                 return -EOVERFLOW;
 416
 417         if (req->dst_len < ctx->key_size) {
 418                 req->dst_len = ctx->key_size;
 419                 return -EOVERFLOW;
 420         }
 421
 422         req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
 423                                   GFP_KERNEL);
 424         if (!req_ctx->in_buf)
 425                 return -ENOMEM;
 426
 427         ps_end = ctx->key_size - digest_info_size - req->src_len - 2;
 428         req_ctx->in_buf[0] = 0x01;
 429         memset(req_ctx->in_buf + 1, 0xff, ps_end - 1);
 430         req_ctx->in_buf[ps_end] = 0x00;
 431
 432         if (digest_info)
 433                 memcpy(req_ctx->in_buf + ps_end + 1, digest_info->data,
 434                        digest_info->size);
 435
 436         pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
 437                         ctx->key_size - 1 - req->src_len, req->src);
 438
 439         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 440         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 441                         pkcs1pad_encrypt_sign_complete_cb, req);
 442
 443         /* Reuse output buffer */
 444         akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
 445                                    req->dst, ctx->key_size - 1, req->dst_len);
 446
 447         err = crypto_akcipher_decrypt(&req_ctx->child_req);
 448         if (err != -EINPROGRESS && err != -EBUSY)
 449                 return pkcs1pad_encrypt_sign_complete(req, err);
 450
 451         return err;
 452 }
 453
 454 static int pkcs1pad_verify_complete(struct akcipher_request *req, int err)
 455 {
 456         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 457         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 458         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 459         struct akcipher_instance *inst = akcipher_alg_instance(tfm);
 460         struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
 461         const struct rsa_asn1_template *digest_info = ictx->digest_info;
 462         const unsigned int sig_size = req->src_len;
 463         const unsigned int digest_size = req->dst_len;
 464         unsigned int dst_len;
 465         unsigned int pos;
 466         u8 *out_buf;
 467
 468         if (err)
 469                 goto done;
 470
 471         err = -EINVAL;
 472         dst_len = req_ctx->child_req.dst_len;
 473         if (dst_len < ctx->key_size - 1)
 474                 goto done;
 475
 476         out_buf = req_ctx->out_buf;
 477         if (dst_len == ctx->key_size) {
 478                 if (out_buf[0] != 0x00)
 479                         /* Decrypted value had no leading 0 byte */
 480                         goto done;
 481
 482                 dst_len--;
 483                 out_buf++;
 484         }
 485
 486         err = -EBADMSG;
 487         if (out_buf[0] != 0x01)
 488                 goto done;
 489
 490         for (pos = 1; pos < dst_len; pos++)
 491                 if (out_buf[pos] != 0xff)
 492                         break;
 493
 494         if (pos < 9 || pos == dst_len || out_buf[pos] != 0x00)
 495                 goto done;
 496         pos++;
 497
 498         if (digest_info) {
 499                 if (digest_info->size > dst_len - pos)
 500                         goto done;
 501                 if (crypto_memneq(out_buf + pos, digest_info->data,
 502                                   digest_info->size))
 503                         goto done;
 504
 505                 pos += digest_info->size;
 506         }
 507
 508         err = 0;
 509
 510         if (digest_size != dst_len - pos) {
 511                 err = -EKEYREJECTED;
 512                 req->dst_len = dst_len - pos;
 513                 goto done;
 514         }
 515         /* Extract appended digest. */
 516         sg_pcopy_to_buffer(req->src,
 517                            sg_nents_for_len(req->src, sig_size + digest_size),
 518                            req_ctx->out_buf + ctx->key_size,
 519                            digest_size, sig_size);
 520         /* Do the actual verification step. */
 521         if (memcmp(req_ctx->out_buf + ctx->key_size, out_buf + pos,
 522                    digest_size) != 0)
 523                 err = -EKEYREJECTED;
 524 done:
 525         kfree_sensitive(req_ctx->out_buf);
 526
 527         return err;
 528 }
 529
 530 static void pkcs1pad_verify_complete_cb(void *data, int err)
 531 {
 532         struct akcipher_request *req = data;
 533
 534         if (err == -EINPROGRESS)
 535                 goto out;
 536
 537         err = pkcs1pad_verify_complete(req, err);
 538
 539 out:
 540         akcipher_request_complete(req, err);
 541 }
 542
 543 /*
 544  * The verify operation is here for completeness similar to the verification
 545  * defined in RFC2313 section 10.2 except that block type 0 is not accepted,
 546  * as in RFC2437.  RFC2437 section 9.2 doesn't define any operation to
 547  * retrieve the DigestInfo from a signature, instead the user is expected
 548  * to call the sign operation to generate the expected signature and compare
 549  * signatures instead of the message-digests.
 550  */
 551 static int pkcs1pad_verify(struct akcipher_request *req)
 552 {
 553         struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
 554         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 555         struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
 556         const unsigned int sig_size = req->src_len;
 557         const unsigned int digest_size = req->dst_len;
 558         int err;
 559
 560         if (WARN_ON(req->dst) || WARN_ON(!digest_size) ||
 561             !ctx->key_size || sig_size != ctx->key_size)
 562                 return -EINVAL;
 563
 564         req_ctx->out_buf = kmalloc(ctx->key_size + digest_size, GFP_KERNEL);
 565         if (!req_ctx->out_buf)
 566                 return -ENOMEM;
 567
 568         pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
 569                             ctx->key_size, NULL);
 570
 571         akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
 572         akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
 573                         pkcs1pad_verify_complete_cb, req);
 574
 575         /* Reuse input buffer, output to a new buffer */
 576         akcipher_request_set_crypt(&req_ctx->child_req, req->src,
 577                                    req_ctx->out_sg, sig_size, ctx->key_size);
 578
 579         err = crypto_akcipher_encrypt(&req_ctx->child_req);
 580         if (err != -EINPROGRESS && err != -EBUSY)
 581                 return pkcs1pad_verify_complete(req, err);
 582
 583         return err;
 584 }
 585
 586 static int pkcs1pad_init_tfm(struct crypto_akcipher *tfm)
 587 {
 588         struct akcipher_instance *inst = akcipher_alg_instance(tfm);
 589         struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
 590         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 591         struct crypto_akcipher *child_tfm;
 592
 593         child_tfm = crypto_spawn_akcipher(&ictx->spawn);
 594         if (IS_ERR(child_tfm))
 595                 return PTR_ERR(child_tfm);
 596
 597         ctx->child = child_tfm;
 598
 599         akcipher_set_reqsize(tfm, sizeof(struct pkcs1pad_request) +
 600                                   crypto_akcipher_reqsize(child_tfm));
 601
 602         return 0;
 603 }
 604
 605 static void pkcs1pad_exit_tfm(struct crypto_akcipher *tfm)
 606 {
 607         struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
 608
 609         crypto_free_akcipher(ctx->child);
 610 }
 611
 612 static void pkcs1pad_free(struct akcipher_instance *inst)
 613 {
 614         struct pkcs1pad_inst_ctx *ctx = akcipher_instance_ctx(inst);
 615         struct crypto_akcipher_spawn *spawn = &ctx->spawn;
 616
 617         crypto_drop_akcipher(spawn);
 618         kfree(inst);
 619 }
 620
 621 static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)
 622 {
 623         u32 mask;
 624         struct akcipher_instance *inst;
 625         struct pkcs1pad_inst_ctx *ctx;
 626         struct akcipher_alg *rsa_alg;
 627         const char *hash_name;
 628         int err;
 629
 630         err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AKCIPHER, &mask);
 631         if (err)
 632                 return err;
 633
 634         inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
 635         if (!inst)
 636                 return -ENOMEM;
 637
 638         ctx = akcipher_instance_ctx(inst);
 639
 640         err = crypto_grab_akcipher(&ctx->spawn, akcipher_crypto_instance(inst),
 641                                    crypto_attr_alg_name(tb[1]), 0, mask);
 642         if (err)
 643                 goto err_free_inst;
 644
 645         rsa_alg = crypto_spawn_akcipher_alg(&ctx->spawn);
 646
 647         if (strcmp(rsa_alg->base.cra_name, "rsa") != 0) {
 648                 err = -EINVAL;
 649                 goto err_free_inst;
 650         }
 651
 652         err = -ENAMETOOLONG;
 653         hash_name = crypto_attr_alg_name(tb[2]);
 654         if (IS_ERR(hash_name)) {
 655                 if (snprintf(inst->alg.base.cra_name,
 656                              CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)",
 657                              rsa_alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
 658                         goto err_free_inst;
 659
 660                 if (snprintf(inst->alg.base.cra_driver_name,
 661                              CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)",
 662                              rsa_alg->base.cra_driver_name) >=
 663                              CRYPTO_MAX_ALG_NAME)
 664                         goto err_free_inst;
 665         } else {
 666                 ctx->digest_info = rsa_lookup_asn1(hash_name);
 667                 if (!ctx->digest_info) {
 668                         err = -EINVAL;
 669                         goto err_free_inst;
 670                 }
 671
 672                 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
 673                              "pkcs1pad(%s,%s)", rsa_alg->base.cra_name,
 674                              hash_name) >= CRYPTO_MAX_ALG_NAME)
 675                         goto err_free_inst;
 676
 677                 if (snprintf(inst->alg.base.cra_driver_name,
 678                              CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s,%s)",
 679                              rsa_alg->base.cra_driver_name,
 680                              hash_name) >= CRYPTO_MAX_ALG_NAME)
 681                         goto err_free_inst;
 682         }
 683
 684         inst->alg.base.cra_priority = rsa_alg->base.cra_priority;
 685         inst->alg.base.cra_ctxsize = sizeof(struct pkcs1pad_ctx);
 686
 687         inst->alg.init = pkcs1pad_init_tfm;
 688         inst->alg.exit = pkcs1pad_exit_tfm;
 689
 690         inst->alg.encrypt = pkcs1pad_encrypt;
 691         inst->alg.decrypt = pkcs1pad_decrypt;
 692         inst->alg.sign = pkcs1pad_sign;
 693         inst->alg.verify = pkcs1pad_verify;
 694         inst->alg.set_pub_key = pkcs1pad_set_pub_key;
 695         inst->alg.set_priv_key = pkcs1pad_set_priv_key;
 696         inst->alg.max_size = pkcs1pad_get_max_size;
 697
 698         inst->free = pkcs1pad_free;
 699
 700         err = akcipher_register_instance(tmpl, inst);
 701         if (err) {
 702 err_free_inst:
 703                 pkcs1pad_free(inst);
 704         }
 705         return err;
 706 }
 707
 708 struct crypto_template rsa_pkcs1pad_tmpl = {
 709         .name = "pkcs1pad",
 710         .create = pkcs1pad_create,
 711         .module = THIS_MODULE,
 712 };
 713
 714 MODULE_ALIAS_CRYPTO("pkcs1pad");