crypto/drbg.c

   1 /*
   2  * DRBG: Deterministic Random Bits Generator
   3  *       Based on NIST Recommended DRBG from NIST SP800-90A with the following
   4  *       properties:
   5  *              * CTR DRBG with DF with AES-128, AES-192, AES-256 cores
   6  *              * Hash DRBG with DF with SHA-1, SHA-256, SHA-384, SHA-512 cores
   7  *              * HMAC DRBG with DF with SHA-1, SHA-256, SHA-384, SHA-512 cores
   8  *              * with and without prediction resistance
   9  *
  10  * Copyright Stephan Mueller <smueller@chronox.de>, 2014
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, and the entire permission notice in its entirety,
  17  *    including the disclaimer of warranties.
  18  * 2. Redistributions in binary form must reproduce the above copyright
  19  *    notice, this list of conditions and the following disclaimer in the
  20  *    documentation and/or other materials provided with the distribution.
  21  * 3. The name of the author may not be used to endorse or promote
  22  *    products derived from this software without specific prior
  23  *    written permission.
  24  *
  25  * ALTERNATIVELY, this product may be distributed under the terms of
  26  * the GNU General Public License, in which case the provisions of the GPL are
  27  * required INSTEAD OF the above restrictions.  (This clause is
  28  * necessary due to a potential bad interaction between the GPL and
  29  * the restrictions contained in a BSD-style copyright.)
  30  *
  31  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  32  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  33  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
  34  * WHICH ARE HEREBY DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE
  35  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  36  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
  37  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  38  * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  39  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  40  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
  41  * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
  42  * DAMAGE.
  43  *
  44  * DRBG Usage
  45  * ==========
  46  * The SP 800-90A DRBG allows the user to specify a personalization string
  47  * for initialization as well as an additional information string for each
  48  * random number request. The following code fragments show how a caller
  49  * uses the kernel crypto API to use the full functionality of the DRBG.
  50  *
  51  * Usage without any additional data
  52  * ---------------------------------
  53  * struct crypto_rng *drng;
  54  * int err;
  55  * char data[DATALEN];
  56  *
  57  * drng = crypto_alloc_rng(drng_name, 0, 0);
  58  * err = crypto_rng_get_bytes(drng, &data, DATALEN);
  59  * crypto_free_rng(drng);
  60  *
  61  *
  62  * Usage with personalization string during initialization
  63  * -------------------------------------------------------
  64  * struct crypto_rng *drng;
  65  * int err;
  66  * char data[DATALEN];
  67  * struct drbg_string pers;
  68  * char personalization[11] = "some-string";
  69  *
  70  * drbg_string_fill(&pers, personalization, strlen(personalization));
  71  * drng = crypto_alloc_rng(drng_name, 0, 0);
  72  * // The reset completely re-initializes the DRBG with the provided
  73  * // personalization string
  74  * err = crypto_rng_reset(drng, &personalization, strlen(personalization));
  75  * err = crypto_rng_get_bytes(drng, &data, DATALEN);
  76  * crypto_free_rng(drng);
  77  *
  78  *
  79  * Usage with additional information string during random number request
  80  * ---------------------------------------------------------------------
  81  * struct crypto_rng *drng;
  82  * int err;
  83  * char data[DATALEN];
  84  * char addtl_string[11] = "some-string";
  85  * string drbg_string addtl;
  86  *
  87  * drbg_string_fill(&addtl, addtl_string, strlen(addtl_string));
  88  * drng = crypto_alloc_rng(drng_name, 0, 0);
  89  * // The following call is a wrapper to crypto_rng_get_bytes() and returns
  90  * // the same error codes.
  91  * err = crypto_drbg_get_bytes_addtl(drng, &data, DATALEN, &addtl);
  92  * crypto_free_rng(drng);
  93  *
  94  *
  95  * Usage with personalization and additional information strings
  96  * -------------------------------------------------------------
  97  * Just mix both scenarios above.
  98  */
  99
 100 #include <crypto/drbg.h>
 101 #include <linux/kernel.h>
 102
 103 /***************************************************************
 104  * Backend cipher definitions available to DRBG
 105  ***************************************************************/
 106
 107 /*
 108  * The order of the DRBG definitions here matter: every DRBG is registered
 109  * as stdrng. Each DRBG receives an increasing cra_priority values the later
 110  * they are defined in this array (see drbg_fill_array).
 111  *
 112  * HMAC DRBGs are favored over Hash DRBGs over CTR DRBGs, and
 113  * the SHA256 / AES 256 over other ciphers. Thus, the favored
 114  * DRBGs are the latest entries in this array.
 115  */
 116 static const struct drbg_core drbg_cores[] = {
 117 #ifdef CONFIG_CRYPTO_DRBG_CTR
 118         {
 119                 .flags = DRBG_CTR | DRBG_STRENGTH128,
 120                 .statelen = 32, /* 256 bits as defined in 10.2.1 */
 121                 .blocklen_bytes = 16,
 122                 .cra_name = "ctr_aes128",
 123                 .backend_cra_name = "aes",
 124         }, {
 125                 .flags = DRBG_CTR | DRBG_STRENGTH192,
 126                 .statelen = 40, /* 320 bits as defined in 10.2.1 */
 127                 .blocklen_bytes = 16,
 128                 .cra_name = "ctr_aes192",
 129                 .backend_cra_name = "aes",
 130         }, {
 131                 .flags = DRBG_CTR | DRBG_STRENGTH256,
 132                 .statelen = 48, /* 384 bits as defined in 10.2.1 */
 133                 .blocklen_bytes = 16,
 134                 .cra_name = "ctr_aes256",
 135                 .backend_cra_name = "aes",
 136         },
 137 #endif /* CONFIG_CRYPTO_DRBG_CTR */
 138 #ifdef CONFIG_CRYPTO_DRBG_HASH
 139         {
 140                 .flags = DRBG_HASH | DRBG_STRENGTH128,
 141                 .statelen = 55, /* 440 bits */
 142                 .blocklen_bytes = 20,
 143                 .cra_name = "sha1",
 144                 .backend_cra_name = "sha1",
 145         }, {
 146                 .flags = DRBG_HASH | DRBG_STRENGTH256,
 147                 .statelen = 111, /* 888 bits */
 148                 .blocklen_bytes = 48,
 149                 .cra_name = "sha384",
 150                 .backend_cra_name = "sha384",
 151         }, {
 152                 .flags = DRBG_HASH | DRBG_STRENGTH256,
 153                 .statelen = 111, /* 888 bits */
 154                 .blocklen_bytes = 64,
 155                 .cra_name = "sha512",
 156                 .backend_cra_name = "sha512",
 157         }, {
 158                 .flags = DRBG_HASH | DRBG_STRENGTH256,
 159                 .statelen = 55, /* 440 bits */
 160                 .blocklen_bytes = 32,
 161                 .cra_name = "sha256",
 162                 .backend_cra_name = "sha256",
 163         },
 164 #endif /* CONFIG_CRYPTO_DRBG_HASH */
 165 #ifdef CONFIG_CRYPTO_DRBG_HMAC
 166         {
 167                 .flags = DRBG_HMAC | DRBG_STRENGTH128,
 168                 .statelen = 20, /* block length of cipher */
 169                 .blocklen_bytes = 20,
 170                 .cra_name = "hmac_sha1",
 171                 .backend_cra_name = "hmac(sha1)",
 172         }, {
 173                 .flags = DRBG_HMAC | DRBG_STRENGTH256,
 174                 .statelen = 48, /* block length of cipher */
 175                 .blocklen_bytes = 48,
 176                 .cra_name = "hmac_sha384",
 177                 .backend_cra_name = "hmac(sha384)",
 178         }, {
 179                 .flags = DRBG_HMAC | DRBG_STRENGTH256,
 180                 .statelen = 64, /* block length of cipher */
 181                 .blocklen_bytes = 64,
 182                 .cra_name = "hmac_sha512",
 183                 .backend_cra_name = "hmac(sha512)",
 184         }, {
 185                 .flags = DRBG_HMAC | DRBG_STRENGTH256,
 186                 .statelen = 32, /* block length of cipher */
 187                 .blocklen_bytes = 32,
 188                 .cra_name = "hmac_sha256",
 189                 .backend_cra_name = "hmac(sha256)",
 190         },
 191 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
 192 };
 193
 194 static int drbg_uninstantiate(struct drbg_state *drbg);
 195
 196 /******************************************************************
 197  * Generic helper functions
 198  ******************************************************************/
 199
 200 /*
 201  * Return strength of DRBG according to SP800-90A section 8.4
 202  *
 203  * @flags DRBG flags reference
 204  *
 205  * Return: normalized strength in *bytes* value or 32 as default
 206  *         to counter programming errors
 207  */
 208 static inline unsigned short drbg_sec_strength(drbg_flag_t flags)
 209 {
 210         switch (flags & DRBG_STRENGTH_MASK) {
 211         case DRBG_STRENGTH128:
 212                 return 16;
 213         case DRBG_STRENGTH192:
 214                 return 24;
 215         case DRBG_STRENGTH256:
 216                 return 32;
 217         default:
 218                 return 32;
 219         }
 220 }
 221
 222 /*
 223  * FIPS 140-2 continuous self test for the noise source
 224  * The test is performed on the noise source input data. Thus, the function
 225  * implicitly knows the size of the buffer to be equal to the security
 226  * strength.
 227  *
 228  * Note, this function disregards the nonce trailing the entropy data during
 229  * initial seeding.
 230  *
 231  * drbg->drbg_mutex must have been taken.
 232  *
 233  * @drbg DRBG handle
 234  * @entropy buffer of seed data to be checked
 235  *
 236  * return:
 237  *      0 on success
 238  *      -EAGAIN on when the CTRNG is not yet primed
 239  *      < 0 on error
 240  */
 241 static int drbg_fips_continuous_test(struct drbg_state *drbg,
 242                                      const unsigned char *entropy)
 243 {
 244         unsigned short entropylen = drbg_sec_strength(drbg->core->flags);
 245         int ret = 0;
 246
 247         if (!IS_ENABLED(CONFIG_CRYPTO_FIPS))
 248                 return 0;
 249
 250         /* skip test if we test the overall system */
 251         if (list_empty(&drbg->test_data.list))
 252                 return 0;
 253         /* only perform test in FIPS mode */
 254         if (!fips_enabled)
 255                 return 0;
 256
 257         if (!drbg->fips_primed) {
 258                 /* Priming of FIPS test */
 259                 memcpy(drbg->prev, entropy, entropylen);
 260                 drbg->fips_primed = true;
 261                 /* priming: another round is needed */
 262                 return -EAGAIN;
 263         }
 264         ret = memcmp(drbg->prev, entropy, entropylen);
 265         if (!ret)
 266                 panic("DRBG continuous self test failed\n");
 267         memcpy(drbg->prev, entropy, entropylen);
 268
 269         /* the test shall pass when the two values are not equal */
 270         return 0;
 271 }
 272
 273 /*
 274  * Convert an integer into a byte representation of this integer.
 275  * The byte representation is big-endian
 276  *
 277  * @val value to be converted
 278  * @buf buffer holding the converted integer -- caller must ensure that
 279  *      buffer size is at least 32 bit
 280  */
 281 #if (defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR))
 282 static inline void drbg_cpu_to_be32(__u32 val, unsigned char *buf)
 283 {
 284         struct s {
 285                 __be32 conv;
 286         };
 287         struct s *conversion = (struct s *) buf;
 288
 289         conversion->conv = cpu_to_be32(val);
 290 }
 291 #endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */
 292
 293 /******************************************************************
 294  * CTR DRBG callback functions
 295  ******************************************************************/
 296
 297 #ifdef CONFIG_CRYPTO_DRBG_CTR
 298 #define CRYPTO_DRBG_CTR_STRING "CTR "
 299 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes256");
 300 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes256");
 301 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes192");
 302 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes192");
 303 MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes128");
 304 MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes128");
 305
 306 static void drbg_kcapi_symsetkey(struct drbg_state *drbg,
 307                                  const unsigned char *key);
 308 static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval,
 309                           const struct drbg_string *in);
 310 static int drbg_init_sym_kernel(struct drbg_state *drbg);
 311 static int drbg_fini_sym_kernel(struct drbg_state *drbg);
 312 static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
 313                               u8 *inbuf, u32 inbuflen,
 314                               u8 *outbuf, u32 outlen);
 315 #define DRBG_OUTSCRATCHLEN 256
 316
 317 /* BCC function for CTR DRBG as defined in 10.4.3 */
 318 static int drbg_ctr_bcc(struct drbg_state *drbg,
 319                         unsigned char *out, const unsigned char *key,
 320                         struct list_head *in)
 321 {
 322         int ret = 0;
 323         struct drbg_string *curr = NULL;
 324         struct drbg_string data;
 325         short cnt = 0;
 326
 327         drbg_string_fill(&data, out, drbg_blocklen(drbg));
 328
 329         /* 10.4.3 step 2 / 4 */
 330         drbg_kcapi_symsetkey(drbg, key);
 331         list_for_each_entry(curr, in, list) {
 332                 const unsigned char *pos = curr->buf;
 333                 size_t len = curr->len;
 334                 /* 10.4.3 step 4.1 */
 335                 while (len) {
 336                         /* 10.4.3 step 4.2 */
 337                         if (drbg_blocklen(drbg) == cnt) {
 338                                 cnt = 0;
 339                                 ret = drbg_kcapi_sym(drbg, out, &data);
 340                                 if (ret)
 341                                         return ret;
 342                         }
 343                         out[cnt] ^= *pos;
 344                         pos++;
 345                         cnt++;
 346                         len--;
 347                 }
 348         }
 349         /* 10.4.3 step 4.2 for last block */
 350         if (cnt)
 351                 ret = drbg_kcapi_sym(drbg, out, &data);
 352
 353         return ret;
 354 }
 355
 356 /*
 357  * scratchpad usage: drbg_ctr_update is interlinked with drbg_ctr_df
 358  * (and drbg_ctr_bcc, but this function does not need any temporary buffers),
 359  * the scratchpad is used as follows:
 360  * drbg_ctr_update:
 361  *      temp
 362  *              start: drbg->scratchpad
 363  *              length: drbg_statelen(drbg) + drbg_blocklen(drbg)
 364  *                      note: the cipher writing into this variable works
 365  *                      blocklen-wise. Now, when the statelen is not a multiple
 366  *                      of blocklen, the generateion loop below "spills over"
 367  *                      by at most blocklen. Thus, we need to give sufficient
 368  *                      memory.
 369  *      df_data
 370  *              start: drbg->scratchpad +
 371  *                              drbg_statelen(drbg) + drbg_blocklen(drbg)
 372  *              length: drbg_statelen(drbg)
 373  *
 374  * drbg_ctr_df:
 375  *      pad
 376  *              start: df_data + drbg_statelen(drbg)
 377  *              length: drbg_blocklen(drbg)
 378  *      iv
 379  *              start: pad + drbg_blocklen(drbg)
 380  *              length: drbg_blocklen(drbg)
 381  *      temp
 382  *              start: iv + drbg_blocklen(drbg)
 383  *              length: drbg_satelen(drbg) + drbg_blocklen(drbg)
 384  *                      note: temp is the buffer that the BCC function operates
 385  *                      on. BCC operates blockwise. drbg_statelen(drbg)
 386  *                      is sufficient when the DRBG state length is a multiple
 387  *                      of the block size. For AES192 (and maybe other ciphers)
 388  *                      this is not correct and the length for temp is
 389  *                      insufficient (yes, that also means for such ciphers,
 390  *                      the final output of all BCC rounds are truncated).
 391  *                      Therefore, add drbg_blocklen(drbg) to cover all
 392  *                      possibilities.
 393  */
 394
 395 /* Derivation Function for CTR DRBG as defined in 10.4.2 */
 396 static int drbg_ctr_df(struct drbg_state *drbg,
 397                        unsigned char *df_data, size_t bytes_to_return,
 398                        struct list_head *seedlist)
 399 {
 400         int ret = -EFAULT;
 401         unsigned char L_N[8];
 402         /* S3 is input */
 403         struct drbg_string S1, S2, S4, cipherin;
 404         LIST_HEAD(bcc_list);
 405         unsigned char *pad = df_data + drbg_statelen(drbg);
 406         unsigned char *iv = pad + drbg_blocklen(drbg);
 407         unsigned char *temp = iv + drbg_blocklen(drbg);
 408         size_t padlen = 0;
 409         unsigned int templen = 0;
 410         /* 10.4.2 step 7 */
 411         unsigned int i = 0;
 412         /* 10.4.2 step 8 */
 413         const unsigned char *K = (unsigned char *)
 414                            "\x00\x01\x02\x03\x04\x05\x06\x07"
 415                            "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
 416                            "\x10\x11\x12\x13\x14\x15\x16\x17"
 417                            "\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f";
 418         unsigned char *X;
 419         size_t generated_len = 0;
 420         size_t inputlen = 0;
 421         struct drbg_string *seed = NULL;
 422
 423         memset(pad, 0, drbg_blocklen(drbg));
 424         memset(iv, 0, drbg_blocklen(drbg));
 425
 426         /* 10.4.2 step 1 is implicit as we work byte-wise */
 427
 428         /* 10.4.2 step 2 */
 429         if ((512/8) < bytes_to_return)
 430                 return -EINVAL;
 431
 432         /* 10.4.2 step 2 -- calculate the entire length of all input data */
 433         list_for_each_entry(seed, seedlist, list)
 434                 inputlen += seed->len;
 435         drbg_cpu_to_be32(inputlen, &L_N[0]);
 436
 437         /* 10.4.2 step 3 */
 438         drbg_cpu_to_be32(bytes_to_return, &L_N[4]);
 439
 440         /* 10.4.2 step 5: length is L_N, input_string, one byte, padding */
 441         padlen = (inputlen + sizeof(L_N) + 1) % (drbg_blocklen(drbg));
 442         /* wrap the padlen appropriately */
 443         if (padlen)
 444                 padlen = drbg_blocklen(drbg) - padlen;
 445         /*
 446          * pad / padlen contains the 0x80 byte and the following zero bytes.
 447          * As the calculated padlen value only covers the number of zero
 448          * bytes, this value has to be incremented by one for the 0x80 byte.
 449          */
 450         padlen++;
 451         pad[0] = 0x80;
 452
 453         /* 10.4.2 step 4 -- first fill the linked list and then order it */
 454         drbg_string_fill(&S1, iv, drbg_blocklen(drbg));
 455         list_add_tail(&S1.list, &bcc_list);
 456         drbg_string_fill(&S2, L_N, sizeof(L_N));
 457         list_add_tail(&S2.list, &bcc_list);
 458         list_splice_tail(seedlist, &bcc_list);
 459         drbg_string_fill(&S4, pad, padlen);
 460         list_add_tail(&S4.list, &bcc_list);
 461
 462         /* 10.4.2 step 9 */
 463         while (templen < (drbg_keylen(drbg) + (drbg_blocklen(drbg)))) {
 464                 /*
 465                  * 10.4.2 step 9.1 - the padding is implicit as the buffer
 466                  * holds zeros after allocation -- even the increment of i
 467                  * is irrelevant as the increment remains within length of i
 468                  */
 469                 drbg_cpu_to_be32(i, iv);
 470                 /* 10.4.2 step 9.2 -- BCC and concatenation with temp */
 471                 ret = drbg_ctr_bcc(drbg, temp + templen, K, &bcc_list);
 472                 if (ret)
 473                         goto out;
 474                 /* 10.4.2 step 9.3 */
 475                 i++;
 476                 templen += drbg_blocklen(drbg);
 477         }
 478
 479         /* 10.4.2 step 11 */
 480         X = temp + (drbg_keylen(drbg));
 481         drbg_string_fill(&cipherin, X, drbg_blocklen(drbg));
 482
 483         /* 10.4.2 step 12: overwriting of outval is implemented in next step */
 484
 485         /* 10.4.2 step 13 */
 486         drbg_kcapi_symsetkey(drbg, temp);
 487         while (generated_len < bytes_to_return) {
 488                 short blocklen = 0;
 489                 /*
 490                  * 10.4.2 step 13.1: the truncation of the key length is
 491                  * implicit as the key is only drbg_blocklen in size based on
 492                  * the implementation of the cipher function callback
 493                  */
 494                 ret = drbg_kcapi_sym(drbg, X, &cipherin);
 495                 if (ret)
 496                         goto out;
 497                 blocklen = (drbg_blocklen(drbg) <
 498                                 (bytes_to_return - generated_len)) ?
 499                             drbg_blocklen(drbg) :
 500                                 (bytes_to_return - generated_len);
 501                 /* 10.4.2 step 13.2 and 14 */
 502                 memcpy(df_data + generated_len, X, blocklen);
 503                 generated_len += blocklen;
 504         }
 505
 506         ret = 0;
 507
 508 out:
 509         memset(iv, 0, drbg_blocklen(drbg));
 510         memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
 511         memset(pad, 0, drbg_blocklen(drbg));
 512         return ret;
 513 }
 514
 515 /*
 516  * update function of CTR DRBG as defined in 10.2.1.2
 517  *
 518  * The reseed variable has an enhanced meaning compared to the update
 519  * functions of the other DRBGs as follows:
 520  * 0 => initial seed from initialization
 521  * 1 => reseed via drbg_seed
 522  * 2 => first invocation from drbg_ctr_update when addtl is present. In
 523  *      this case, the df_data scratchpad is not deleted so that it is
 524  *      available for another calls to prevent calling the DF function
 525  *      again.
 526  * 3 => second invocation from drbg_ctr_update. When the update function
 527  *      was called with addtl, the df_data memory already contains the
 528  *      DFed addtl information and we do not need to call DF again.
 529  */
 530 static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed,
 531                            int reseed)
 532 {
 533         int ret = -EFAULT;
 534         /* 10.2.1.2 step 1 */
 535         unsigned char *temp = drbg->scratchpad;
 536         unsigned char *df_data = drbg->scratchpad + drbg_statelen(drbg) +
 537                                  drbg_blocklen(drbg);
 538
 539         if (3 > reseed)
 540                 memset(df_data, 0, drbg_statelen(drbg));
 541
 542         if (!reseed) {
 543                 /*
 544                  * The DRBG uses the CTR mode of the underlying AES cipher. The
 545                  * CTR mode increments the counter value after the AES operation
 546                  * but SP800-90A requires that the counter is incremented before
 547                  * the AES operation. Hence, we increment it at the time we set
 548                  * it by one.
 549                  */
 550                 crypto_inc(drbg->V, drbg_blocklen(drbg));
 551
 552                 ret = crypto_skcipher_setkey(drbg->ctr_handle, drbg->C,
 553                                              drbg_keylen(drbg));
 554                 if (ret)
 555                         goto out;
 556         }
 557
 558         /* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */
 559         if (seed) {
 560                 ret = drbg_ctr_df(drbg, df_data, drbg_statelen(drbg), seed);
 561                 if (ret)
 562                         goto out;
 563         }
 564
 565         ret = drbg_kcapi_sym_ctr(drbg, df_data, drbg_statelen(drbg),
 566                                  temp, drbg_statelen(drbg));
 567         if (ret)
 568                 return ret;
 569
 570         /* 10.2.1.2 step 5 */
 571         ret = crypto_skcipher_setkey(drbg->ctr_handle, temp,
 572                                      drbg_keylen(drbg));
 573         if (ret)
 574                 goto out;
 575         /* 10.2.1.2 step 6 */
 576         memcpy(drbg->V, temp + drbg_keylen(drbg), drbg_blocklen(drbg));
 577         /* See above: increment counter by one to compensate timing of CTR op */
 578         crypto_inc(drbg->V, drbg_blocklen(drbg));
 579         ret = 0;
 580
 581 out:
 582         memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
 583         if (2 != reseed)
 584                 memset(df_data, 0, drbg_statelen(drbg));
 585         return ret;
 586 }
 587
 588 /*
 589  * scratchpad use: drbg_ctr_update is called independently from
 590  * drbg_ctr_extract_bytes. Therefore, the scratchpad is reused
 591  */
 592 /* Generate function of CTR DRBG as defined in 10.2.1.5.2 */
 593 static int drbg_ctr_generate(struct drbg_state *drbg,
 594                              unsigned char *buf, unsigned int buflen,
 595                              struct list_head *addtl)
 596 {
 597         int ret;
 598         int len = min_t(int, buflen, INT_MAX);
 599
 600         /* 10.2.1.5.2 step 2 */
 601         if (addtl && !list_empty(addtl)) {
 602                 ret = drbg_ctr_update(drbg, addtl, 2);
 603                 if (ret)
 604                         return 0;
 605         }
 606
 607         /* 10.2.1.5.2 step 4.1 */
 608         ret = drbg_kcapi_sym_ctr(drbg, NULL, 0, buf, len);
 609         if (ret)
 610                 return ret;
 611
 612         /* 10.2.1.5.2 step 6 */
 613         ret = drbg_ctr_update(drbg, NULL, 3);
 614         if (ret)
 615                 len = ret;
 616
 617         return len;
 618 }
 619
 620 static const struct drbg_state_ops drbg_ctr_ops = {
 621         .update         = drbg_ctr_update,
 622         .generate       = drbg_ctr_generate,
 623         .crypto_init    = drbg_init_sym_kernel,
 624         .crypto_fini    = drbg_fini_sym_kernel,
 625 };
 626 #endif /* CONFIG_CRYPTO_DRBG_CTR */
 627
 628 /******************************************************************
 629  * HMAC DRBG callback functions
 630  ******************************************************************/
 631
 632 #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
 633 static int drbg_kcapi_hash(struct drbg_state *drbg, unsigned char *outval,
 634                            const struct list_head *in);
 635 static void drbg_kcapi_hmacsetkey(struct drbg_state *drbg,
 636                                   const unsigned char *key);
 637 static int drbg_init_hash_kernel(struct drbg_state *drbg);
 638 static int drbg_fini_hash_kernel(struct drbg_state *drbg);
 639 #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
 640
 641 #ifdef CONFIG_CRYPTO_DRBG_HMAC
 642 #define CRYPTO_DRBG_HMAC_STRING "HMAC "
 643 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha512");
 644 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha512");
 645 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha384");
 646 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha384");
 647 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha256");
 648 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha256");
 649 MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha1");
 650 MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha1");
 651
 652 /* update function of HMAC DRBG as defined in 10.1.2.2 */
 653 static int drbg_hmac_update(struct drbg_state *drbg, struct list_head *seed,
 654                             int reseed)
 655 {
 656         int ret = -EFAULT;
 657         int i = 0;
 658         struct drbg_string seed1, seed2, vdata;
 659         LIST_HEAD(seedlist);
 660         LIST_HEAD(vdatalist);
 661
 662         if (!reseed) {
 663                 /* 10.1.2.3 step 2 -- memset(0) of C is implicit with kzalloc */
 664                 memset(drbg->V, 1, drbg_statelen(drbg));
 665                 drbg_kcapi_hmacsetkey(drbg, drbg->C);
 666         }
 667
 668         drbg_string_fill(&seed1, drbg->V, drbg_statelen(drbg));
 669         list_add_tail(&seed1.list, &seedlist);
 670         /* buffer of seed2 will be filled in for loop below with one byte */
 671         drbg_string_fill(&seed2, NULL, 1);
 672         list_add_tail(&seed2.list, &seedlist);
 673         /* input data of seed is allowed to be NULL at this point */
 674         if (seed)
 675                 list_splice_tail(seed, &seedlist);
 676
 677         drbg_string_fill(&vdata, drbg->V, drbg_statelen(drbg));
 678         list_add_tail(&vdata.list, &vdatalist);
 679         for (i = 2; 0 < i; i--) {
 680                 /* first round uses 0x0, second 0x1 */
 681                 unsigned char prefix = DRBG_PREFIX0;
 682                 if (1 == i)
 683                         prefix = DRBG_PREFIX1;
 684                 /* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */
 685                 seed2.buf = &prefix;
 686                 ret = drbg_kcapi_hash(drbg, drbg->C, &seedlist);
 687                 if (ret)
 688                         return ret;
 689                 drbg_kcapi_hmacsetkey(drbg, drbg->C);
 690
 691                 /* 10.1.2.2 step 2 and 5 -- HMAC for V */
 692                 ret = drbg_kcapi_hash(drbg, drbg->V, &vdatalist);
 693                 if (ret)
 694                         return ret;
 695
 696                 /* 10.1.2.2 step 3 */
 697                 if (!seed)
 698                         return ret;
 699         }
 700
 701         return 0;
 702 }
 703
 704 /* generate function of HMAC DRBG as defined in 10.1.2.5 */
 705 static int drbg_hmac_generate(struct drbg_state *drbg,
 706                               unsigned char *buf,
 707                               unsigned int buflen,
 708                               struct list_head *addtl)
 709 {
 710         int len = 0;
 711         int ret = 0;
 712         struct drbg_string data;
 713         LIST_HEAD(datalist);
 714
 715         /* 10.1.2.5 step 2 */
 716         if (addtl && !list_empty(addtl)) {
 717                 ret = drbg_hmac_update(drbg, addtl, 1);
 718                 if (ret)
 719                         return ret;
 720         }
 721
 722         drbg_string_fill(&data, drbg->V, drbg_statelen(drbg));
 723         list_add_tail(&data.list, &datalist);
 724         while (len < buflen) {
 725                 unsigned int outlen = 0;
 726                 /* 10.1.2.5 step 4.1 */
 727                 ret = drbg_kcapi_hash(drbg, drbg->V, &datalist);
 728                 if (ret)
 729                         return ret;
 730                 outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
 731                           drbg_blocklen(drbg) : (buflen - len);
 732
 733                 /* 10.1.2.5 step 4.2 */
 734                 memcpy(buf + len, drbg->V, outlen);
 735                 len += outlen;
 736         }
 737
 738         /* 10.1.2.5 step 6 */
 739         if (addtl && !list_empty(addtl))
 740                 ret = drbg_hmac_update(drbg, addtl, 1);
 741         else
 742                 ret = drbg_hmac_update(drbg, NULL, 1);
 743         if (ret)
 744                 return ret;
 745
 746         return len;
 747 }
 748
 749 static const struct drbg_state_ops drbg_hmac_ops = {
 750         .update         = drbg_hmac_update,
 751         .generate       = drbg_hmac_generate,
 752         .crypto_init    = drbg_init_hash_kernel,
 753         .crypto_fini    = drbg_fini_hash_kernel,
 754 };
 755 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
 756
 757 /******************************************************************
 758  * Hash DRBG callback functions
 759  ******************************************************************/
 760
 761 #ifdef CONFIG_CRYPTO_DRBG_HASH
 762 #define CRYPTO_DRBG_HASH_STRING "HASH "
 763 MODULE_ALIAS_CRYPTO("drbg_pr_sha512");
 764 MODULE_ALIAS_CRYPTO("drbg_nopr_sha512");
 765 MODULE_ALIAS_CRYPTO("drbg_pr_sha384");
 766 MODULE_ALIAS_CRYPTO("drbg_nopr_sha384");
 767 MODULE_ALIAS_CRYPTO("drbg_pr_sha256");
 768 MODULE_ALIAS_CRYPTO("drbg_nopr_sha256");
 769 MODULE_ALIAS_CRYPTO("drbg_pr_sha1");
 770 MODULE_ALIAS_CRYPTO("drbg_nopr_sha1");
 771
 772 /*
 773  * Increment buffer
 774  *
 775  * @dst buffer to increment
 776  * @add value to add
 777  */
 778 static inline void drbg_add_buf(unsigned char *dst, size_t dstlen,
 779                                 const unsigned char *add, size_t addlen)
 780 {
 781         /* implied: dstlen > addlen */
 782         unsigned char *dstptr;
 783         const unsigned char *addptr;
 784         unsigned int remainder = 0;
 785         size_t len = addlen;
 786
 787         dstptr = dst + (dstlen-1);
 788         addptr = add + (addlen-1);
 789         while (len) {
 790                 remainder += *dstptr + *addptr;
 791                 *dstptr = remainder & 0xff;
 792                 remainder >>= 8;
 793                 len--; dstptr--; addptr--;
 794         }
 795         len = dstlen - addlen;
 796         while (len && remainder > 0) {
 797                 remainder = *dstptr + 1;
 798                 *dstptr = remainder & 0xff;
 799                 remainder >>= 8;
 800                 len--; dstptr--;
 801         }
 802 }
 803
 804 /*
 805  * scratchpad usage: as drbg_hash_update and drbg_hash_df are used
 806  * interlinked, the scratchpad is used as follows:
 807  * drbg_hash_update
 808  *      start: drbg->scratchpad
 809  *      length: drbg_statelen(drbg)
 810  * drbg_hash_df:
 811  *      start: drbg->scratchpad + drbg_statelen(drbg)
 812  *      length: drbg_blocklen(drbg)
 813  *
 814  * drbg_hash_process_addtl uses the scratchpad, but fully completes
 815  * before either of the functions mentioned before are invoked. Therefore,
 816  * drbg_hash_process_addtl does not need to be specifically considered.
 817  */
 818
 819 /* Derivation Function for Hash DRBG as defined in 10.4.1 */
 820 static int drbg_hash_df(struct drbg_state *drbg,
 821                         unsigned char *outval, size_t outlen,
 822                         struct list_head *entropylist)
 823 {
 824         int ret = 0;
 825         size_t len = 0;
 826         unsigned char input[5];
 827         unsigned char *tmp = drbg->scratchpad + drbg_statelen(drbg);
 828         struct drbg_string data;
 829
 830         /* 10.4.1 step 3 */
 831         input[0] = 1;
 832         drbg_cpu_to_be32((outlen * 8), &input[1]);
 833
 834         /* 10.4.1 step 4.1 -- concatenation of data for input into hash */
 835         drbg_string_fill(&data, input, 5);
 836         list_add(&data.list, entropylist);
 837
 838         /* 10.4.1 step 4 */
 839         while (len < outlen) {
 840                 short blocklen = 0;
 841                 /* 10.4.1 step 4.1 */
 842                 ret = drbg_kcapi_hash(drbg, tmp, entropylist);
 843                 if (ret)
 844                         goto out;
 845                 /* 10.4.1 step 4.2 */
 846                 input[0]++;
 847                 blocklen = (drbg_blocklen(drbg) < (outlen - len)) ?
 848                             drbg_blocklen(drbg) : (outlen - len);
 849                 memcpy(outval + len, tmp, blocklen);
 850                 len += blocklen;
 851         }
 852
 853 out:
 854         memset(tmp, 0, drbg_blocklen(drbg));
 855         return ret;
 856 }
 857
 858 /* update function for Hash DRBG as defined in 10.1.1.2 / 10.1.1.3 */
 859 static int drbg_hash_update(struct drbg_state *drbg, struct list_head *seed,
 860                             int reseed)
 861 {
 862         int ret = 0;
 863         struct drbg_string data1, data2;
 864         LIST_HEAD(datalist);
 865         LIST_HEAD(datalist2);
 866         unsigned char *V = drbg->scratchpad;
 867         unsigned char prefix = DRBG_PREFIX1;
 868
 869         if (!seed)
 870                 return -EINVAL;
 871
 872         if (reseed) {
 873                 /* 10.1.1.3 step 1 */
 874                 memcpy(V, drbg->V, drbg_statelen(drbg));
 875                 drbg_string_fill(&data1, &prefix, 1);
 876                 list_add_tail(&data1.list, &datalist);
 877                 drbg_string_fill(&data2, V, drbg_statelen(drbg));
 878                 list_add_tail(&data2.list, &datalist);
 879         }
 880         list_splice_tail(seed, &datalist);
 881
 882         /* 10.1.1.2 / 10.1.1.3 step 2 and 3 */
 883         ret = drbg_hash_df(drbg, drbg->V, drbg_statelen(drbg), &datalist);
 884         if (ret)
 885                 goto out;
 886
 887         /* 10.1.1.2 / 10.1.1.3 step 4  */
 888         prefix = DRBG_PREFIX0;
 889         drbg_string_fill(&data1, &prefix, 1);
 890         list_add_tail(&data1.list, &datalist2);
 891         drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
 892         list_add_tail(&data2.list, &datalist2);
 893         /* 10.1.1.2 / 10.1.1.3 step 4 */
 894         ret = drbg_hash_df(drbg, drbg->C, drbg_statelen(drbg), &datalist2);
 895
 896 out:
 897         memset(drbg->scratchpad, 0, drbg_statelen(drbg));
 898         return ret;
 899 }
 900
 901 /* processing of additional information string for Hash DRBG */
 902 static int drbg_hash_process_addtl(struct drbg_state *drbg,
 903                                    struct list_head *addtl)
 904 {
 905         int ret = 0;
 906         struct drbg_string data1, data2;
 907         LIST_HEAD(datalist);
 908         unsigned char prefix = DRBG_PREFIX2;
 909
 910         /* 10.1.1.4 step 2 */
 911         if (!addtl || list_empty(addtl))
 912                 return 0;
 913
 914         /* 10.1.1.4 step 2a */
 915         drbg_string_fill(&data1, &prefix, 1);
 916         drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
 917         list_add_tail(&data1.list, &datalist);
 918         list_add_tail(&data2.list, &datalist);
 919         list_splice_tail(addtl, &datalist);
 920         ret = drbg_kcapi_hash(drbg, drbg->scratchpad, &datalist);
 921         if (ret)
 922                 goto out;
 923
 924         /* 10.1.1.4 step 2b */
 925         drbg_add_buf(drbg->V, drbg_statelen(drbg),
 926                      drbg->scratchpad, drbg_blocklen(drbg));
 927
 928 out:
 929         memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
 930         return ret;
 931 }
 932
 933 /* Hashgen defined in 10.1.1.4 */
 934 static int drbg_hash_hashgen(struct drbg_state *drbg,
 935                              unsigned char *buf,
 936                              unsigned int buflen)
 937 {
 938         int len = 0;
 939         int ret = 0;
 940         unsigned char *src = drbg->scratchpad;
 941         unsigned char *dst = drbg->scratchpad + drbg_statelen(drbg);
 942         struct drbg_string data;
 943         LIST_HEAD(datalist);
 944
 945         /* 10.1.1.4 step hashgen 2 */
 946         memcpy(src, drbg->V, drbg_statelen(drbg));
 947
 948         drbg_string_fill(&data, src, drbg_statelen(drbg));
 949         list_add_tail(&data.list, &datalist);
 950         while (len < buflen) {
 951                 unsigned int outlen = 0;
 952                 /* 10.1.1.4 step hashgen 4.1 */
 953                 ret = drbg_kcapi_hash(drbg, dst, &datalist);
 954                 if (ret) {
 955                         len = ret;
 956                         goto out;
 957                 }
 958                 outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
 959                           drbg_blocklen(drbg) : (buflen - len);
 960                 /* 10.1.1.4 step hashgen 4.2 */
 961                 memcpy(buf + len, dst, outlen);
 962                 len += outlen;
 963                 /* 10.1.1.4 hashgen step 4.3 */
 964                 if (len < buflen)
 965                         crypto_inc(src, drbg_statelen(drbg));
 966         }
 967
 968 out:
 969         memset(drbg->scratchpad, 0,
 970                (drbg_statelen(drbg) + drbg_blocklen(drbg)));
 971         return len;
 972 }
 973
 974 /* generate function for Hash DRBG as defined in  10.1.1.4 */
 975 static int drbg_hash_generate(struct drbg_state *drbg,
 976                               unsigned char *buf, unsigned int buflen,
 977                               struct list_head *addtl)
 978 {
 979         int len = 0;
 980         int ret = 0;
 981         union {
 982                 unsigned char req[8];
 983                 __be64 req_int;
 984         } u;
 985         unsigned char prefix = DRBG_PREFIX3;
 986         struct drbg_string data1, data2;
 987         LIST_HEAD(datalist);
 988
 989         /* 10.1.1.4 step 2 */
 990         ret = drbg_hash_process_addtl(drbg, addtl);
 991         if (ret)
 992                 return ret;
 993         /* 10.1.1.4 step 3 */
 994         len = drbg_hash_hashgen(drbg, buf, buflen);
 995
 996         /* this is the value H as documented in 10.1.1.4 */
 997         /* 10.1.1.4 step 4 */
 998         drbg_string_fill(&data1, &prefix, 1);
 999         list_add_tail(&data1.list, &datalist);
1000         drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
1001         list_add_tail(&data2.list, &datalist);
1002         ret = drbg_kcapi_hash(drbg, drbg->scratchpad, &datalist);
1003         if (ret) {
1004                 len = ret;
1005                 goto out;
1006         }
1007
1008         /* 10.1.1.4 step 5 */
1009         drbg_add_buf(drbg->V, drbg_statelen(drbg),
1010                      drbg->scratchpad, drbg_blocklen(drbg));
1011         drbg_add_buf(drbg->V, drbg_statelen(drbg),
1012                      drbg->C, drbg_statelen(drbg));
1013         u.req_int = cpu_to_be64(drbg->reseed_ctr);
1014         drbg_add_buf(drbg->V, drbg_statelen(drbg), u.req, 8);
1015
1016 out:
1017         memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
1018         return len;
1019 }
1020
1021 /*
1022  * scratchpad usage: as update and generate are used isolated, both
1023  * can use the scratchpad
1024  */
1025 static const struct drbg_state_ops drbg_hash_ops = {
1026         .update         = drbg_hash_update,
1027         .generate       = drbg_hash_generate,
1028         .crypto_init    = drbg_init_hash_kernel,
1029         .crypto_fini    = drbg_fini_hash_kernel,
1030 };
1031 #endif /* CONFIG_CRYPTO_DRBG_HASH */
1032
1033 /******************************************************************
1034  * Functions common for DRBG implementations
1035  ******************************************************************/
1036
1037 static inline int __drbg_seed(struct drbg_state *drbg, struct list_head *seed,
1038                               int reseed, enum drbg_seed_state new_seed_state)
1039 {
1040         int ret = drbg->d_ops->update(drbg, seed, reseed);
1041
1042         if (ret)
1043                 return ret;
1044
1045         drbg->seeded = new_seed_state;
1046         /* 10.1.1.2 / 10.1.1.3 step 5 */
1047         drbg->reseed_ctr = 1;
1048
1049         switch (drbg->seeded) {
1050         case DRBG_SEED_STATE_UNSEEDED:
1051                 /* Impossible, but handle it to silence compiler warnings. */
1052                 fallthrough;
1053         case DRBG_SEED_STATE_PARTIAL:
1054                 /*
1055                  * Require frequent reseeds until the seed source is
1056                  * fully initialized.
1057                  */
1058                 drbg->reseed_threshold = 50;
1059                 break;
1060
1061         case DRBG_SEED_STATE_FULL:
1062                 /*
1063                  * Seed source has become fully initialized, frequent
1064                  * reseeds no longer required.
1065                  */
1066                 drbg->reseed_threshold = drbg_max_requests(drbg);
1067                 break;
1068         }
1069
1070         return ret;
1071 }
1072
1073 static inline int drbg_get_random_bytes(struct drbg_state *drbg,
1074                                         unsigned char *entropy,
1075                                         unsigned int entropylen)
1076 {
1077         int ret;
1078
1079         do {
1080                 get_random_bytes(entropy, entropylen);
1081                 ret = drbg_fips_continuous_test(drbg, entropy);
1082                 if (ret && ret != -EAGAIN)
1083                         return ret;
1084         } while (ret);
1085
1086         return 0;
1087 }
1088
1089 static int drbg_seed_from_random(struct drbg_state *drbg)
1090 {
1091         struct drbg_string data;
1092         LIST_HEAD(seedlist);
1093         unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
1094         unsigned char entropy[32];
1095         int ret;
1096
1097         BUG_ON(!entropylen);
1098         BUG_ON(entropylen > sizeof(entropy));
1099
1100         drbg_string_fill(&data, entropy, entropylen);
1101         list_add_tail(&data.list, &seedlist);
1102
1103         ret = drbg_get_random_bytes(drbg, entropy, entropylen);
1104         if (ret)
1105                 goto out;
1106
1107         ret = __drbg_seed(drbg, &seedlist, true, DRBG_SEED_STATE_FULL);
1108
1109 out:
1110         memzero_explicit(entropy, entropylen);
1111         return ret;
1112 }
1113
1114 /*
1115  * Seeding or reseeding of the DRBG
1116  *
1117  * @drbg: DRBG state struct
1118  * @pers: personalization / additional information buffer
1119  * @reseed: 0 for initial seed process, 1 for reseeding
1120  *
1121  * return:
1122  *      0 on success
1123  *      error value otherwise
1124  */
1125 static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
1126                      bool reseed)
1127 {
1128         int ret;
1129         unsigned char entropy[((32 + 16) * 2)];
1130         unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
1131         struct drbg_string data1;
1132         LIST_HEAD(seedlist);
1133         enum drbg_seed_state new_seed_state = DRBG_SEED_STATE_FULL;
1134
1135         /* 9.1 / 9.2 / 9.3.1 step 3 */
1136         if (pers && pers->len > (drbg_max_addtl(drbg))) {
1137                 pr_devel("DRBG: personalization string too long %zu\n",
1138                          pers->len);
1139                 return -EINVAL;
1140         }
1141
1142         if (list_empty(&drbg->test_data.list)) {
1143                 drbg_string_fill(&data1, drbg->test_data.buf,
1144                                  drbg->test_data.len);
1145                 pr_devel("DRBG: using test entropy\n");
1146         } else {
1147                 /*
1148                  * Gather entropy equal to the security strength of the DRBG.
1149                  * With a derivation function, a nonce is required in addition
1150                  * to the entropy. A nonce must be at least 1/2 of the security
1151                  * strength of the DRBG in size. Thus, entropy + nonce is 3/2
1152                  * of the strength. The consideration of a nonce is only
1153                  * applicable during initial seeding.
1154                  */
1155                 BUG_ON(!entropylen);
1156                 if (!reseed)
1157                         entropylen = ((entropylen + 1) / 2) * 3;
1158                 BUG_ON((entropylen * 2) > sizeof(entropy));
1159
1160                 /* Get seed from in-kernel /dev/urandom */
1161                 if (!rng_is_initialized())
1162                         new_seed_state = DRBG_SEED_STATE_PARTIAL;
1163
1164                 ret = drbg_get_random_bytes(drbg, entropy, entropylen);
1165                 if (ret)
1166                         goto out;
1167
1168                 if (!drbg->jent) {
1169                         drbg_string_fill(&data1, entropy, entropylen);
1170                         pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
1171                                  entropylen);
1172                 } else {
1173                         /* Get seed from Jitter RNG */
1174                         ret = crypto_rng_get_bytes(drbg->jent,
1175                                                    entropy + entropylen,
1176                                                    entropylen);
1177                         if (ret) {
1178                                 pr_devel("DRBG: jent failed with %d\n", ret);
1179
1180                                 /*
1181                                  * Do not treat the transient failure of the
1182                                  * Jitter RNG as an error that needs to be
1183                                  * reported. The combined number of the
1184                                  * maximum reseed threshold times the maximum
1185                                  * number of Jitter RNG transient errors is
1186                                  * less than the reseed threshold required by
1187                                  * SP800-90A allowing us to treat the
1188                                  * transient errors as such.
1189                                  *
1190                                  * However, we mandate that at least the first
1191                                  * seeding operation must succeed with the
1192                                  * Jitter RNG.
1193                                  */
1194                                 if (!reseed || ret != -EAGAIN)
1195                                         goto out;
1196                         }
1197
1198                         drbg_string_fill(&data1, entropy, entropylen * 2);
1199                         pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
1200                                  entropylen * 2);
1201                 }
1202         }
1203         list_add_tail(&data1.list, &seedlist);
1204
1205         /*
1206          * concatenation of entropy with personalization str / addtl input)
1207          * the variable pers is directly handed in by the caller, so check its
1208          * contents whether it is appropriate
1209          */
1210         if (pers && pers->buf && 0 < pers->len) {
1211                 list_add_tail(&pers->list, &seedlist);
1212                 pr_devel("DRBG: using personalization string\n");
1213         }
1214
1215         if (!reseed) {
1216                 memset(drbg->V, 0, drbg_statelen(drbg));
1217                 memset(drbg->C, 0, drbg_statelen(drbg));
1218         }
1219
1220         ret = __drbg_seed(drbg, &seedlist, reseed, new_seed_state);
1221
1222 out:
1223         memzero_explicit(entropy, entropylen * 2);
1224
1225         return ret;
1226 }
1227
1228 /* Free all substructures in a DRBG state without the DRBG state structure */
1229 static inline void drbg_dealloc_state(struct drbg_state *drbg)
1230 {
1231         if (!drbg)
1232                 return;
1233         kzfree(drbg->Vbuf);
1234         drbg->Vbuf = NULL;
1235         drbg->V = NULL;
1236         kzfree(drbg->Cbuf);
1237         drbg->Cbuf = NULL;
1238         drbg->C = NULL;
1239         kzfree(drbg->scratchpadbuf);
1240         drbg->scratchpadbuf = NULL;
1241         drbg->reseed_ctr = 0;
1242         drbg->d_ops = NULL;
1243         drbg->core = NULL;
1244         if (IS_ENABLED(CONFIG_CRYPTO_FIPS)) {
1245                 kzfree(drbg->prev);
1246                 drbg->prev = NULL;
1247                 drbg->fips_primed = false;
1248         }
1249 }
1250
1251 /*
1252  * Allocate all sub-structures for a DRBG state.
1253  * The DRBG state structure must already be allocated.
1254  */
1255 static inline int drbg_alloc_state(struct drbg_state *drbg)
1256 {
1257         int ret = -ENOMEM;
1258         unsigned int sb_size = 0;
1259
1260         switch (drbg->core->flags & DRBG_TYPE_MASK) {
1261 #ifdef CONFIG_CRYPTO_DRBG_HMAC
1262         case DRBG_HMAC:
1263                 drbg->d_ops = &drbg_hmac_ops;
1264                 break;
1265 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
1266 #ifdef CONFIG_CRYPTO_DRBG_HASH
1267         case DRBG_HASH:
1268                 drbg->d_ops = &drbg_hash_ops;
1269                 break;
1270 #endif /* CONFIG_CRYPTO_DRBG_HASH */
1271 #ifdef CONFIG_CRYPTO_DRBG_CTR
1272         case DRBG_CTR:
1273                 drbg->d_ops = &drbg_ctr_ops;
1274                 break;
1275 #endif /* CONFIG_CRYPTO_DRBG_CTR */
1276         default:
1277                 ret = -EOPNOTSUPP;
1278                 goto err;
1279         }
1280
1281         ret = drbg->d_ops->crypto_init(drbg);
1282         if (ret < 0)
1283                 goto err;
1284
1285         drbg->Vbuf = kmalloc(drbg_statelen(drbg) + ret, GFP_KERNEL);
1286         if (!drbg->Vbuf) {
1287                 ret = -ENOMEM;
1288                 goto fini;
1289         }
1290         drbg->V = PTR_ALIGN(drbg->Vbuf, ret + 1);
1291         drbg->Cbuf = kmalloc(drbg_statelen(drbg) + ret, GFP_KERNEL);
1292         if (!drbg->Cbuf) {
1293                 ret = -ENOMEM;
1294                 goto fini;
1295         }
1296         drbg->C = PTR_ALIGN(drbg->Cbuf, ret + 1);
1297         /* scratchpad is only generated for CTR and Hash */
1298         if (drbg->core->flags & DRBG_HMAC)
1299                 sb_size = 0;
1300         else if (drbg->core->flags & DRBG_CTR)
1301                 sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg) + /* temp */
1302                           drbg_statelen(drbg) + /* df_data */
1303                           drbg_blocklen(drbg) + /* pad */
1304                           drbg_blocklen(drbg) + /* iv */
1305                           drbg_statelen(drbg) + drbg_blocklen(drbg); /* temp */
1306         else
1307                 sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg);
1308
1309         if (0 < sb_size) {
1310                 drbg->scratchpadbuf = kzalloc(sb_size + ret, GFP_KERNEL);
1311                 if (!drbg->scratchpadbuf) {
1312                         ret = -ENOMEM;
1313                         goto fini;
1314                 }
1315                 drbg->scratchpad = PTR_ALIGN(drbg->scratchpadbuf, ret + 1);
1316         }
1317
1318         if (IS_ENABLED(CONFIG_CRYPTO_FIPS)) {
1319                 drbg->prev = kzalloc(drbg_sec_strength(drbg->core->flags),
1320                                      GFP_KERNEL);
1321                 if (!drbg->prev) {
1322                         ret = -ENOMEM;
1323                         goto fini;
1324                 }
1325                 drbg->fips_primed = false;
1326         }
1327
1328         return 0;
1329
1330 fini:
1331         drbg->d_ops->crypto_fini(drbg);
1332 err:
1333         drbg_dealloc_state(drbg);
1334         return ret;
1335 }
1336
1337 /*************************************************************************
1338  * DRBG interface functions
1339  *************************************************************************/
1340
1341 /*
1342  * DRBG generate function as required by SP800-90A - this function
1343  * generates random numbers
1344  *
1345  * @drbg DRBG state handle
1346  * @buf Buffer where to store the random numbers -- the buffer must already
1347  *      be pre-allocated by caller
1348  * @buflen Length of output buffer - this value defines the number of random
1349  *         bytes pulled from DRBG
1350  * @addtl Additional input that is mixed into state, may be NULL -- note
1351  *        the entropy is pulled by the DRBG internally unconditionally
1352  *        as defined in SP800-90A. The additional input is mixed into
1353  *        the state in addition to the pulled entropy.
1354  *
1355  * return: 0 when all bytes are generated; < 0 in case of an error
1356  */
1357 static int drbg_generate(struct drbg_state *drbg,
1358                          unsigned char *buf, unsigned int buflen,
1359                          struct drbg_string *addtl)
1360 {
1361         int len = 0;
1362         LIST_HEAD(addtllist);
1363
1364         if (!drbg->core) {
1365                 pr_devel("DRBG: not yet seeded\n");
1366                 return -EINVAL;
1367         }
1368         if (0 == buflen || !buf) {
1369                 pr_devel("DRBG: no output buffer provided\n");
1370                 return -EINVAL;
1371         }
1372         if (addtl && NULL == addtl->buf && 0 < addtl->len) {
1373                 pr_devel("DRBG: wrong format of additional information\n");
1374                 return -EINVAL;
1375         }
1376
1377         /* 9.3.1 step 2 */
1378         len = -EINVAL;
1379         if (buflen > (drbg_max_request_bytes(drbg))) {
1380                 pr_devel("DRBG: requested random numbers too large %u\n",
1381                          buflen);
1382                 goto err;
1383         }
1384
1385         /* 9.3.1 step 3 is implicit with the chosen DRBG */
1386
1387         /* 9.3.1 step 4 */
1388         if (addtl && addtl->len > (drbg_max_addtl(drbg))) {
1389                 pr_devel("DRBG: additional information string too long %zu\n",
1390                          addtl->len);
1391                 goto err;
1392         }
1393         /* 9.3.1 step 5 is implicit with the chosen DRBG */
1394
1395         /*
1396          * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented
1397          * here. The spec is a bit convoluted here, we make it simpler.
1398          */
1399         if (drbg->reseed_threshold < drbg->reseed_ctr)
1400                 drbg->seeded = DRBG_SEED_STATE_UNSEEDED;
1401
1402         if (drbg->pr || drbg->seeded == DRBG_SEED_STATE_UNSEEDED) {
1403                 pr_devel("DRBG: reseeding before generation (prediction "
1404                          "resistance: %s, state %s)\n",
1405                          drbg->pr ? "true" : "false",
1406                          (drbg->seeded ==  DRBG_SEED_STATE_FULL ?
1407                           "seeded" : "unseeded"));
1408                 /* 9.3.1 steps 7.1 through 7.3 */
1409                 len = drbg_seed(drbg, addtl, true);
1410                 if (len)
1411                         goto err;
1412                 /* 9.3.1 step 7.4 */
1413                 addtl = NULL;
1414         } else if (rng_is_initialized() &&
1415                    drbg->seeded == DRBG_SEED_STATE_PARTIAL) {
1416                 len = drbg_seed_from_random(drbg);
1417                 if (len)
1418                         goto err;
1419         }
1420
1421         if (addtl && 0 < addtl->len)
1422                 list_add_tail(&addtl->list, &addtllist);
1423         /* 9.3.1 step 8 and 10 */
1424         len = drbg->d_ops->generate(drbg, buf, buflen, &addtllist);
1425
1426         /* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */
1427         drbg->reseed_ctr++;
1428         if (0 >= len)
1429                 goto err;
1430
1431         /*
1432          * Section 11.3.3 requires to re-perform self tests after some
1433          * generated random numbers. The chosen value after which self
1434          * test is performed is arbitrary, but it should be reasonable.
1435          * However, we do not perform the self tests because of the following
1436          * reasons: it is mathematically impossible that the initial self tests
1437          * were successfully and the following are not. If the initial would
1438          * pass and the following would not, the kernel integrity is violated.
1439          * In this case, the entire kernel operation is questionable and it
1440          * is unlikely that the integrity violation only affects the
1441          * correct operation of the DRBG.
1442          *
1443          * Albeit the following code is commented out, it is provided in
1444          * case somebody has a need to implement the test of 11.3.3.
1445          */
1446 #if 0
1447         if (drbg->reseed_ctr && !(drbg->reseed_ctr % 4096)) {
1448                 int err = 0;
1449                 pr_devel("DRBG: start to perform self test\n");
1450                 if (drbg->core->flags & DRBG_HMAC)
1451                         err = alg_test("drbg_pr_hmac_sha256",
1452                                        "drbg_pr_hmac_sha256", 0, 0);
1453                 else if (drbg->core->flags & DRBG_CTR)
1454                         err = alg_test("drbg_pr_ctr_aes128",
1455                                        "drbg_pr_ctr_aes128", 0, 0);
1456                 else
1457                         err = alg_test("drbg_pr_sha256",
1458                                        "drbg_pr_sha256", 0, 0);
1459                 if (err) {
1460                         pr_err("DRBG: periodical self test failed\n");
1461                         /*
1462                          * uninstantiate implies that from now on, only errors
1463                          * are returned when reusing this DRBG cipher handle
1464                          */
1465                         drbg_uninstantiate(drbg);
1466                         return 0;
1467                 } else {
1468                         pr_devel("DRBG: self test successful\n");
1469                 }
1470         }
1471 #endif
1472
1473         /*
1474          * All operations were successful, return 0 as mandated by
1475          * the kernel crypto API interface.
1476          */
1477         len = 0;
1478 err:
1479         return len;
1480 }
1481
1482 /*
1483  * Wrapper around drbg_generate which can pull arbitrary long strings
1484  * from the DRBG without hitting the maximum request limitation.
1485  *
1486  * Parameters: see drbg_generate
1487  * Return codes: see drbg_generate -- if one drbg_generate request fails,
1488  *               the entire drbg_generate_long request fails
1489  */
1490 static int drbg_generate_long(struct drbg_state *drbg,
1491                               unsigned char *buf, unsigned int buflen,
1492                               struct drbg_string *addtl)
1493 {
1494         unsigned int len = 0;
1495         unsigned int slice = 0;
1496         do {
1497                 int err = 0;
1498                 unsigned int chunk = 0;
1499                 slice = ((buflen - len) / drbg_max_request_bytes(drbg));
1500                 chunk = slice ? drbg_max_request_bytes(drbg) : (buflen - len);
1501                 mutex_lock(&drbg->drbg_mutex);
1502                 err = drbg_generate(drbg, buf + len, chunk, addtl);
1503                 mutex_unlock(&drbg->drbg_mutex);
1504                 if (0 > err)
1505                         return err;
1506                 len += chunk;
1507         } while (slice > 0 && (len < buflen));
1508         return 0;
1509 }
1510
1511 static int drbg_prepare_hrng(struct drbg_state *drbg)
1512 {
1513         /* We do not need an HRNG in test mode. */
1514         if (list_empty(&drbg->test_data.list))
1515                 return 0;
1516
1517         drbg->jent = crypto_alloc_rng("jitterentropy_rng", 0, 0);
1518
1519         return 0;
1520 }
1521
1522 /*
1523  * DRBG instantiation function as required by SP800-90A - this function
1524  * sets up the DRBG handle, performs the initial seeding and all sanity
1525  * checks required by SP800-90A
1526  *
1527  * @drbg memory of state -- if NULL, new memory is allocated
1528  * @pers Personalization string that is mixed into state, may be NULL -- note
1529  *       the entropy is pulled by the DRBG internally unconditionally
1530  *       as defined in SP800-90A. The additional input is mixed into
1531  *       the state in addition to the pulled entropy.
1532  * @coreref reference to core
1533  * @pr prediction resistance enabled
1534  *
1535  * return
1536  *      0 on success
1537  *      error value otherwise
1538  */
1539 static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers,
1540                             int coreref, bool pr)
1541 {
1542         int ret;
1543         bool reseed = true;
1544
1545         pr_devel("DRBG: Initializing DRBG core %d with prediction resistance "
1546                  "%s\n", coreref, pr ? "enabled" : "disabled");
1547         mutex_lock(&drbg->drbg_mutex);
1548
1549         /* 9.1 step 1 is implicit with the selected DRBG type */
1550
1551         /*
1552          * 9.1 step 2 is implicit as caller can select prediction resistance
1553          * and the flag is copied into drbg->flags --
1554          * all DRBG types support prediction resistance
1555          */
1556
1557         /* 9.1 step 4 is implicit in  drbg_sec_strength */
1558
1559         if (!drbg->core) {
1560                 drbg->core = &drbg_cores[coreref];
1561                 drbg->pr = pr;
1562                 drbg->seeded = DRBG_SEED_STATE_UNSEEDED;
1563                 drbg->reseed_threshold = drbg_max_requests(drbg);
1564
1565                 ret = drbg_alloc_state(drbg);
1566                 if (ret)
1567                         goto unlock;
1568
1569                 ret = drbg_prepare_hrng(drbg);
1570                 if (ret)
1571                         goto free_everything;
1572
1573                 if (IS_ERR(drbg->jent)) {
1574                         ret = PTR_ERR(drbg->jent);
1575                         drbg->jent = NULL;
1576                         if (fips_enabled || ret != -ENOENT)
1577                                 goto free_everything;
1578                         pr_info("DRBG: Continuing without Jitter RNG\n");
1579                 }
1580
1581                 reseed = false;
1582         }
1583
1584         ret = drbg_seed(drbg, pers, reseed);
1585
1586         if (ret && !reseed)
1587                 goto free_everything;
1588
1589         mutex_unlock(&drbg->drbg_mutex);
1590         return ret;
1591
1592 unlock:
1593         mutex_unlock(&drbg->drbg_mutex);
1594         return ret;
1595
1596 free_everything:
1597         mutex_unlock(&drbg->drbg_mutex);
1598         drbg_uninstantiate(drbg);
1599         return ret;
1600 }
1601
1602 /*
1603  * DRBG uninstantiate function as required by SP800-90A - this function
1604  * frees all buffers and the DRBG handle
1605  *
1606  * @drbg DRBG state handle
1607  *
1608  * return
1609  *      0 on success
1610  */
1611 static int drbg_uninstantiate(struct drbg_state *drbg)
1612 {
1613         if (!IS_ERR_OR_NULL(drbg->jent))
1614                 crypto_free_rng(drbg->jent);
1615         drbg->jent = NULL;
1616
1617         if (drbg->d_ops)
1618                 drbg->d_ops->crypto_fini(drbg);
1619         drbg_dealloc_state(drbg);
1620         /* no scrubbing of test_data -- this shall survive an uninstantiate */
1621         return 0;
1622 }
1623
1624 /*
1625  * Helper function for setting the test data in the DRBG
1626  *
1627  * @drbg DRBG state handle
1628  * @data test data
1629  * @len test data length
1630  */
1631 static void drbg_kcapi_set_entropy(struct crypto_rng *tfm,
1632                                    const u8 *data, unsigned int len)
1633 {
1634         struct drbg_state *drbg = crypto_rng_ctx(tfm);
1635
1636         mutex_lock(&drbg->drbg_mutex);
1637         drbg_string_fill(&drbg->test_data, data, len);
1638         mutex_unlock(&drbg->drbg_mutex);
1639 }
1640
1641 /***************************************************************
1642  * Kernel crypto API cipher invocations requested by DRBG
1643  ***************************************************************/
1644
1645 #if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
1646 struct sdesc {
1647         struct shash_desc shash;
1648         char ctx[];
1649 };
1650
1651 static int drbg_init_hash_kernel(struct drbg_state *drbg)
1652 {
1653         struct sdesc *sdesc;
1654         struct crypto_shash *tfm;
1655
1656         tfm = crypto_alloc_shash(drbg->core->backend_cra_name, 0, 0);
1657         if (IS_ERR(tfm)) {
1658                 pr_info("DRBG: could not allocate digest TFM handle: %s\n",
1659                                 drbg->core->backend_cra_name);
1660                 return PTR_ERR(tfm);
1661         }
1662         BUG_ON(drbg_blocklen(drbg) != crypto_shash_digestsize(tfm));
1663         sdesc = kzalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm),
1664                         GFP_KERNEL);
1665         if (!sdesc) {
1666                 crypto_free_shash(tfm);
1667                 return -ENOMEM;
1668         }
1669
1670         sdesc->shash.tfm = tfm;
1671         drbg->priv_data = sdesc;
1672
1673         return crypto_shash_alignmask(tfm);
1674 }
1675
1676 static int drbg_fini_hash_kernel(struct drbg_state *drbg)
1677 {
1678         struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
1679         if (sdesc) {
1680                 crypto_free_shash(sdesc->shash.tfm);
1681                 kzfree(sdesc);
1682         }
1683         drbg->priv_data = NULL;
1684         return 0;
1685 }
1686
1687 static void drbg_kcapi_hmacsetkey(struct drbg_state *drbg,
1688                                   const unsigned char *key)
1689 {
1690         struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
1691
1692         crypto_shash_setkey(sdesc->shash.tfm, key, drbg_statelen(drbg));
1693 }
1694
1695 static int drbg_kcapi_hash(struct drbg_state *drbg, unsigned char *outval,
1696                            const struct list_head *in)
1697 {
1698         struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
1699         struct drbg_string *input = NULL;
1700
1701         crypto_shash_init(&sdesc->shash);
1702         list_for_each_entry(input, in, list)
1703                 crypto_shash_update(&sdesc->shash, input->buf, input->len);
1704         return crypto_shash_final(&sdesc->shash, outval);
1705 }
1706 #endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
1707
1708 #ifdef CONFIG_CRYPTO_DRBG_CTR
1709 static int drbg_fini_sym_kernel(struct drbg_state *drbg)
1710 {
1711         struct crypto_cipher *tfm =
1712                 (struct crypto_cipher *)drbg->priv_data;
1713         if (tfm)
1714                 crypto_free_cipher(tfm);
1715         drbg->priv_data = NULL;
1716
1717         if (drbg->ctr_handle)
1718                 crypto_free_skcipher(drbg->ctr_handle);
1719         drbg->ctr_handle = NULL;
1720
1721         if (drbg->ctr_req)
1722                 skcipher_request_free(drbg->ctr_req);
1723         drbg->ctr_req = NULL;
1724
1725         kfree(drbg->outscratchpadbuf);
1726         drbg->outscratchpadbuf = NULL;
1727
1728         return 0;
1729 }
1730
1731 static int drbg_init_sym_kernel(struct drbg_state *drbg)
1732 {
1733         struct crypto_cipher *tfm;
1734         struct crypto_skcipher *sk_tfm;
1735         struct skcipher_request *req;
1736         unsigned int alignmask;
1737         char ctr_name[CRYPTO_MAX_ALG_NAME];
1738
1739         tfm = crypto_alloc_cipher(drbg->core->backend_cra_name, 0, 0);
1740         if (IS_ERR(tfm)) {
1741                 pr_info("DRBG: could not allocate cipher TFM handle: %s\n",
1742                                 drbg->core->backend_cra_name);
1743                 return PTR_ERR(tfm);
1744         }
1745         BUG_ON(drbg_blocklen(drbg) != crypto_cipher_blocksize(tfm));
1746         drbg->priv_data = tfm;
1747
1748         if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)",
1749             drbg->core->backend_cra_name) >= CRYPTO_MAX_ALG_NAME) {
1750                 drbg_fini_sym_kernel(drbg);
1751                 return -EINVAL;
1752         }
1753         sk_tfm = crypto_alloc_skcipher(ctr_name, 0, 0);
1754         if (IS_ERR(sk_tfm)) {
1755                 pr_info("DRBG: could not allocate CTR cipher TFM handle: %s\n",
1756                                 ctr_name);
1757                 drbg_fini_sym_kernel(drbg);
1758                 return PTR_ERR(sk_tfm);
1759         }
1760         drbg->ctr_handle = sk_tfm;
1761         crypto_init_wait(&drbg->ctr_wait);
1762
1763         req = skcipher_request_alloc(sk_tfm, GFP_KERNEL);
1764         if (!req) {
1765                 pr_info("DRBG: could not allocate request queue\n");
1766                 drbg_fini_sym_kernel(drbg);
1767                 return -ENOMEM;
1768         }
1769         drbg->ctr_req = req;
1770         skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
1771                                                 CRYPTO_TFM_REQ_MAY_SLEEP,
1772                                         crypto_req_done, &drbg->ctr_wait);
1773
1774         alignmask = crypto_skcipher_alignmask(sk_tfm);
1775         drbg->outscratchpadbuf = kmalloc(DRBG_OUTSCRATCHLEN + alignmask,
1776                                          GFP_KERNEL);
1777         if (!drbg->outscratchpadbuf) {
1778                 drbg_fini_sym_kernel(drbg);
1779                 return -ENOMEM;
1780         }
1781         drbg->outscratchpad = (u8 *)PTR_ALIGN(drbg->outscratchpadbuf,
1782                                               alignmask + 1);
1783
1784         sg_init_table(&drbg->sg_in, 1);
1785         sg_init_one(&drbg->sg_out, drbg->outscratchpad, DRBG_OUTSCRATCHLEN);
1786
1787         return alignmask;
1788 }
1789
1790 static void drbg_kcapi_symsetkey(struct drbg_state *drbg,
1791                                  const unsigned char *key)
1792 {
1793         struct crypto_cipher *tfm =
1794                 (struct crypto_cipher *)drbg->priv_data;
1795
1796         crypto_cipher_setkey(tfm, key, (drbg_keylen(drbg)));
1797 }
1798
1799 static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval,
1800                           const struct drbg_string *in)
1801 {
1802         struct crypto_cipher *tfm =
1803                 (struct crypto_cipher *)drbg->priv_data;
1804
1805         /* there is only component in *in */
1806         BUG_ON(in->len < drbg_blocklen(drbg));
1807         crypto_cipher_encrypt_one(tfm, outval, in->buf);
1808         return 0;
1809 }
1810
1811 static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
1812                               u8 *inbuf, u32 inlen,
1813                               u8 *outbuf, u32 outlen)
1814 {
1815         struct scatterlist *sg_in = &drbg->sg_in, *sg_out = &drbg->sg_out;
1816         u32 scratchpad_use = min_t(u32, outlen, DRBG_OUTSCRATCHLEN);
1817         int ret;
1818
1819         if (inbuf) {
1820                 /* Use caller-provided input buffer */
1821                 sg_set_buf(sg_in, inbuf, inlen);
1822         } else {
1823                 /* Use scratchpad for in-place operation */
1824                 inlen = scratchpad_use;
1825                 memset(drbg->outscratchpad, 0, scratchpad_use);
1826                 sg_set_buf(sg_in, drbg->outscratchpad, scratchpad_use);
1827         }
1828
1829         while (outlen) {
1830                 u32 cryptlen = min3(inlen, outlen, (u32)DRBG_OUTSCRATCHLEN);
1831
1832                 /* Output buffer may not be valid for SGL, use scratchpad */
1833                 skcipher_request_set_crypt(drbg->ctr_req, sg_in, sg_out,
1834                                            cryptlen, drbg->V);
1835                 ret = crypto_wait_req(crypto_skcipher_encrypt(drbg->ctr_req),
1836                                         &drbg->ctr_wait);
1837                 if (ret)
1838                         goto out;
1839
1840                 crypto_init_wait(&drbg->ctr_wait);
1841
1842                 memcpy(outbuf, drbg->outscratchpad, cryptlen);
1843                 memzero_explicit(drbg->outscratchpad, cryptlen);
1844
1845                 outlen -= cryptlen;
1846                 outbuf += cryptlen;
1847         }
1848         ret = 0;
1849
1850 out:
1851         return ret;
1852 }
1853 #endif /* CONFIG_CRYPTO_DRBG_CTR */
1854
1855 /***************************************************************
1856  * Kernel crypto API interface to register DRBG
1857  ***************************************************************/
1858
1859 /*
1860  * Look up the DRBG flags by given kernel crypto API cra_name
1861  * The code uses the drbg_cores definition to do this
1862  *
1863  * @cra_name kernel crypto API cra_name
1864  * @coreref reference to integer which is filled with the pointer to
1865  *  the applicable core
1866  * @pr reference for setting prediction resistance
1867  *
1868  * return: flags
1869  */
1870 static inline void drbg_convert_tfm_core(const char *cra_driver_name,
1871                                          int *coreref, bool *pr)
1872 {
1873         int i = 0;
1874         size_t start = 0;
1875         int len = 0;
1876
1877         *pr = true;
1878         /* disassemble the names */
1879         if (!memcmp(cra_driver_name, "drbg_nopr_", 10)) {
1880                 start = 10;
1881                 *pr = false;
1882         } else if (!memcmp(cra_driver_name, "drbg_pr_", 8)) {
1883                 start = 8;
1884         } else {
1885                 return;
1886         }
1887
1888         /* remove the first part */
1889         len = strlen(cra_driver_name) - start;
1890         for (i = 0; ARRAY_SIZE(drbg_cores) > i; i++) {
1891                 if (!memcmp(cra_driver_name + start, drbg_cores[i].cra_name,
1892                             len)) {
1893                         *coreref = i;
1894                         return;
1895                 }
1896         }
1897 }
1898
1899 static int drbg_kcapi_init(struct crypto_tfm *tfm)
1900 {
1901         struct drbg_state *drbg = crypto_tfm_ctx(tfm);
1902
1903         mutex_init(&drbg->drbg_mutex);
1904
1905         return 0;
1906 }
1907
1908 static void drbg_kcapi_cleanup(struct crypto_tfm *tfm)
1909 {
1910         drbg_uninstantiate(crypto_tfm_ctx(tfm));
1911 }
1912
1913 /*
1914  * Generate random numbers invoked by the kernel crypto API:
1915  * The API of the kernel crypto API is extended as follows:
1916  *
1917  * src is additional input supplied to the RNG.
1918  * slen is the length of src.
1919  * dst is the output buffer where random data is to be stored.
1920  * dlen is the length of dst.
1921  */
1922 static int drbg_kcapi_random(struct crypto_rng *tfm,
1923                              const u8 *src, unsigned int slen,
1924                              u8 *dst, unsigned int dlen)
1925 {
1926         struct drbg_state *drbg = crypto_rng_ctx(tfm);
1927         struct drbg_string *addtl = NULL;
1928         struct drbg_string string;
1929
1930         if (slen) {
1931                 /* linked list variable is now local to allow modification */
1932                 drbg_string_fill(&string, src, slen);
1933                 addtl = &string;
1934         }
1935
1936         return drbg_generate_long(drbg, dst, dlen, addtl);
1937 }
1938
1939 /*
1940  * Seed the DRBG invoked by the kernel crypto API
1941  */
1942 static int drbg_kcapi_seed(struct crypto_rng *tfm,
1943                            const u8 *seed, unsigned int slen)
1944 {
1945         struct drbg_state *drbg = crypto_rng_ctx(tfm);
1946         struct crypto_tfm *tfm_base = crypto_rng_tfm(tfm);
1947         bool pr = false;
1948         struct drbg_string string;
1949         struct drbg_string *seed_string = NULL;
1950         int coreref = 0;
1951
1952         drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base), &coreref,
1953                               &pr);
1954         if (0 < slen) {
1955                 drbg_string_fill(&string, seed, slen);
1956                 seed_string = &string;
1957         }
1958
1959         return drbg_instantiate(drbg, seed_string, coreref, pr);
1960 }
1961
1962 /***************************************************************
1963  * Kernel module: code to load the module
1964  ***************************************************************/
1965
1966 /*
1967  * Tests as defined in 11.3.2 in addition to the cipher tests: testing
1968  * of the error handling.
1969  *
1970  * Note: testing of failing seed source as defined in 11.3.2 is not applicable
1971  * as seed source of get_random_bytes does not fail.
1972  *
1973  * Note 2: There is no sensible way of testing the reseed counter
1974  * enforcement, so skip it.
1975  */
1976 static inline int __init drbg_healthcheck_sanity(void)
1977 {
1978         int len = 0;
1979 #define OUTBUFLEN 16
1980         unsigned char buf[OUTBUFLEN];
1981         struct drbg_state *drbg = NULL;
1982         int ret = -EFAULT;
1983         int rc = -EFAULT;
1984         bool pr = false;
1985         int coreref = 0;
1986         struct drbg_string addtl;
1987         size_t max_addtllen, max_request_bytes;
1988
1989         /* only perform test in FIPS mode */
1990         if (!fips_enabled)
1991                 return 0;
1992
1993 #ifdef CONFIG_CRYPTO_DRBG_CTR
1994         drbg_convert_tfm_core("drbg_nopr_ctr_aes128", &coreref, &pr);
1995 #elif defined CONFIG_CRYPTO_DRBG_HASH
1996         drbg_convert_tfm_core("drbg_nopr_sha256", &coreref, &pr);
1997 #else
1998         drbg_convert_tfm_core("drbg_nopr_hmac_sha256", &coreref, &pr);
1999 #endif
2000
2001         drbg = kzalloc(sizeof(struct drbg_state), GFP_KERNEL);
2002         if (!drbg)
2003                 return -ENOMEM;
2004
2005         mutex_init(&drbg->drbg_mutex);
2006         drbg->core = &drbg_cores[coreref];
2007         drbg->reseed_threshold = drbg_max_requests(drbg);
2008
2009         /*
2010          * if the following tests fail, it is likely that there is a buffer
2011          * overflow as buf is much smaller than the requested or provided
2012          * string lengths -- in case the error handling does not succeed
2013          * we may get an OOPS. And we want to get an OOPS as this is a
2014          * grave bug.
2015          */
2016
2017         max_addtllen = drbg_max_addtl(drbg);
2018         max_request_bytes = drbg_max_request_bytes(drbg);
2019         drbg_string_fill(&addtl, buf, max_addtllen + 1);
2020         /* overflow addtllen with additonal info string */
2021         len = drbg_generate(drbg, buf, OUTBUFLEN, &addtl);
2022         BUG_ON(0 < len);
2023         /* overflow max_bits */
2024         len = drbg_generate(drbg, buf, (max_request_bytes + 1), NULL);
2025         BUG_ON(0 < len);
2026
2027         /* overflow max addtllen with personalization string */
2028         ret = drbg_seed(drbg, &addtl, false);
2029         BUG_ON(0 == ret);
2030         /* all tests passed */
2031         rc = 0;
2032
2033         pr_devel("DRBG: Sanity tests for failure code paths successfully "
2034                  "completed\n");
2035
2036         kfree(drbg);
2037         return rc;
2038 }
2039
2040 static struct rng_alg drbg_algs[22];
2041
2042 /*
2043  * Fill the array drbg_algs used to register the different DRBGs
2044  * with the kernel crypto API. To fill the array, the information
2045  * from drbg_cores[] is used.
2046  */
2047 static inline void __init drbg_fill_array(struct rng_alg *alg,
2048                                           const struct drbg_core *core, int pr)
2049 {
2050         int pos = 0;
2051         static int priority = 200;
2052
2053         memcpy(alg->base.cra_name, "stdrng", 6);
2054         if (pr) {
2055                 memcpy(alg->base.cra_driver_name, "drbg_pr_", 8);
2056                 pos = 8;
2057         } else {
2058                 memcpy(alg->base.cra_driver_name, "drbg_nopr_", 10);
2059                 pos = 10;
2060         }
2061         memcpy(alg->base.cra_driver_name + pos, core->cra_name,
2062                strlen(core->cra_name));
2063
2064         alg->base.cra_priority = priority;
2065         priority++;
2066         /*
2067          * If FIPS mode enabled, the selected DRBG shall have the
2068          * highest cra_priority over other stdrng instances to ensure
2069          * it is selected.
2070          */
2071         if (fips_enabled)
2072                 alg->base.cra_priority += 200;
2073
2074         alg->base.cra_ctxsize   = sizeof(struct drbg_state);
2075         alg->base.cra_module    = THIS_MODULE;
2076         alg->base.cra_init      = drbg_kcapi_init;
2077         alg->base.cra_exit      = drbg_kcapi_cleanup;
2078         alg->generate           = drbg_kcapi_random;
2079         alg->seed               = drbg_kcapi_seed;
2080         alg->set_ent            = drbg_kcapi_set_entropy;
2081         alg->seedsize           = 0;
2082 }
2083
2084 static int __init drbg_init(void)
2085 {
2086         unsigned int i = 0; /* pointer to drbg_algs */
2087         unsigned int j = 0; /* pointer to drbg_cores */
2088         int ret;
2089
2090         ret = drbg_healthcheck_sanity();
2091         if (ret)
2092                 return ret;
2093
2094         if (ARRAY_SIZE(drbg_cores) * 2 > ARRAY_SIZE(drbg_algs)) {
2095                 pr_info("DRBG: Cannot register all DRBG types"
2096                         "(slots needed: %zu, slots available: %zu)\n",
2097                         ARRAY_SIZE(drbg_cores) * 2, ARRAY_SIZE(drbg_algs));
2098                 return -EFAULT;
2099         }
2100
2101         /*
2102          * each DRBG definition can be used with PR and without PR, thus
2103          * we instantiate each DRBG in drbg_cores[] twice.
2104          *
2105          * As the order of placing them into the drbg_algs array matters
2106          * (the later DRBGs receive a higher cra_priority) we register the
2107          * prediction resistance DRBGs first as the should not be too
2108          * interesting.
2109          */
2110         for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
2111                 drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 1);
2112         for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
2113                 drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 0);
2114         return crypto_register_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
2115 }
2116
2117 static void __exit drbg_exit(void)
2118 {
2119         crypto_unregister_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
2120 }
2121
2122 subsys_initcall(drbg_init);
2123 module_exit(drbg_exit);
2124 #ifndef CRYPTO_DRBG_HASH_STRING
2125 #define CRYPTO_DRBG_HASH_STRING ""
2126 #endif
2127 #ifndef CRYPTO_DRBG_HMAC_STRING
2128 #define CRYPTO_DRBG_HMAC_STRING ""
2129 #endif
2130 #ifndef CRYPTO_DRBG_CTR_STRING
2131 #define CRYPTO_DRBG_CTR_STRING ""
2132 #endif
2133 MODULE_LICENSE("GPL");
2134 MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
2135 MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) "
2136                    "using following cores: "
2137                    CRYPTO_DRBG_HASH_STRING
2138                    CRYPTO_DRBG_HMAC_STRING
2139                    CRYPTO_DRBG_CTR_STRING);
2140 MODULE_ALIAS_CRYPTO("stdrng");