linux/crypto/drbg.c
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   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 <crypto/internal/cipher.h>
 102#include <linux/kernel.h>
 103
 104/***************************************************************
 105 * Backend cipher definitions available to DRBG
 106 ***************************************************************/
 107
 108/*
 109 * The order of the DRBG definitions here matter: every DRBG is registered
 110 * as stdrng. Each DRBG receives an increasing cra_priority values the later
 111 * they are defined in this array (see drbg_fill_array).
 112 *
 113 * HMAC DRBGs are favored over Hash DRBGs over CTR DRBGs, and
 114 * the SHA256 / AES 256 over other ciphers. Thus, the favored
 115 * DRBGs are the latest entries in this array.
 116 */
 117static const struct drbg_core drbg_cores[] = {
 118#ifdef CONFIG_CRYPTO_DRBG_CTR
 119        {
 120                .flags = DRBG_CTR | DRBG_STRENGTH128,
 121                .statelen = 32, /* 256 bits as defined in 10.2.1 */
 122                .blocklen_bytes = 16,
 123                .cra_name = "ctr_aes128",
 124                .backend_cra_name = "aes",
 125        }, {
 126                .flags = DRBG_CTR | DRBG_STRENGTH192,
 127                .statelen = 40, /* 320 bits as defined in 10.2.1 */
 128                .blocklen_bytes = 16,
 129                .cra_name = "ctr_aes192",
 130                .backend_cra_name = "aes",
 131        }, {
 132                .flags = DRBG_CTR | DRBG_STRENGTH256,
 133                .statelen = 48, /* 384 bits as defined in 10.2.1 */
 134                .blocklen_bytes = 16,
 135                .cra_name = "ctr_aes256",
 136                .backend_cra_name = "aes",
 137        },
 138#endif /* CONFIG_CRYPTO_DRBG_CTR */
 139#ifdef CONFIG_CRYPTO_DRBG_HASH
 140        {
 141                .flags = DRBG_HASH | DRBG_STRENGTH128,
 142                .statelen = 55, /* 440 bits */
 143                .blocklen_bytes = 20,
 144                .cra_name = "sha1",
 145                .backend_cra_name = "sha1",
 146        }, {
 147                .flags = DRBG_HASH | DRBG_STRENGTH256,
 148                .statelen = 111, /* 888 bits */
 149                .blocklen_bytes = 48,
 150                .cra_name = "sha384",
 151                .backend_cra_name = "sha384",
 152        }, {
 153                .flags = DRBG_HASH | DRBG_STRENGTH256,
 154                .statelen = 111, /* 888 bits */
 155                .blocklen_bytes = 64,
 156                .cra_name = "sha512",
 157                .backend_cra_name = "sha512",
 158        }, {
 159                .flags = DRBG_HASH | DRBG_STRENGTH256,
 160                .statelen = 55, /* 440 bits */
 161                .blocklen_bytes = 32,
 162                .cra_name = "sha256",
 163                .backend_cra_name = "sha256",
 164        },
 165#endif /* CONFIG_CRYPTO_DRBG_HASH */
 166#ifdef CONFIG_CRYPTO_DRBG_HMAC
 167        {
 168                .flags = DRBG_HMAC | DRBG_STRENGTH128,
 169                .statelen = 20, /* block length of cipher */
 170                .blocklen_bytes = 20,
 171                .cra_name = "hmac_sha1",
 172                .backend_cra_name = "hmac(sha1)",
 173        }, {
 174                .flags = DRBG_HMAC | DRBG_STRENGTH256,
 175                .statelen = 48, /* block length of cipher */
 176                .blocklen_bytes = 48,
 177                .cra_name = "hmac_sha384",
 178                .backend_cra_name = "hmac(sha384)",
 179        }, {
 180                .flags = DRBG_HMAC | DRBG_STRENGTH256,
 181                .statelen = 32, /* block length of cipher */
 182                .blocklen_bytes = 32,
 183                .cra_name = "hmac_sha256",
 184                .backend_cra_name = "hmac(sha256)",
 185        }, {
 186                .flags = DRBG_HMAC | DRBG_STRENGTH256,
 187                .statelen = 64, /* block length of cipher */
 188                .blocklen_bytes = 64,
 189                .cra_name = "hmac_sha512",
 190                .backend_cra_name = "hmac(sha512)",
 191        },
 192#endif /* CONFIG_CRYPTO_DRBG_HMAC */
 193};
 194
 195static int drbg_uninstantiate(struct drbg_state *drbg);
 196
 197/******************************************************************
 198 * Generic helper functions
 199 ******************************************************************/
 200
 201/*
 202 * Return strength of DRBG according to SP800-90A section 8.4
 203 *
 204 * @flags DRBG flags reference
 205 *
 206 * Return: normalized strength in *bytes* value or 32 as default
 207 *         to counter programming errors
 208 */
 209static inline unsigned short drbg_sec_strength(drbg_flag_t flags)
 210{
 211        switch (flags & DRBG_STRENGTH_MASK) {
 212        case DRBG_STRENGTH128:
 213                return 16;
 214        case DRBG_STRENGTH192:
 215                return 24;
 216        case DRBG_STRENGTH256:
 217                return 32;
 218        default:
 219                return 32;
 220        }
 221}
 222
 223/*
 224 * FIPS 140-2 continuous self test for the noise source
 225 * The test is performed on the noise source input data. Thus, the function
 226 * implicitly knows the size of the buffer to be equal to the security
 227 * strength.
 228 *
 229 * Note, this function disregards the nonce trailing the entropy data during
 230 * initial seeding.
 231 *
 232 * drbg->drbg_mutex must have been taken.
 233 *
 234 * @drbg DRBG handle
 235 * @entropy buffer of seed data to be checked
 236 *
 237 * return:
 238 *      0 on success
 239 *      -EAGAIN on when the CTRNG is not yet primed
 240 *      < 0 on error
 241 */
 242static int drbg_fips_continuous_test(struct drbg_state *drbg,
 243                                     const unsigned char *entropy)
 244{
 245        unsigned short entropylen = drbg_sec_strength(drbg->core->flags);
 246        int ret = 0;
 247
 248        if (!IS_ENABLED(CONFIG_CRYPTO_FIPS))
 249                return 0;
 250
 251        /* skip test if we test the overall system */
 252        if (list_empty(&drbg->test_data.list))
 253                return 0;
 254        /* only perform test in FIPS mode */
 255        if (!fips_enabled)
 256                return 0;
 257
 258        if (!drbg->fips_primed) {
 259                /* Priming of FIPS test */
 260                memcpy(drbg->prev, entropy, entropylen);
 261                drbg->fips_primed = true;
 262                /* priming: another round is needed */
 263                return -EAGAIN;
 264        }
 265        ret = memcmp(drbg->prev, entropy, entropylen);
 266        if (!ret)
 267                panic("DRBG continuous self test failed\n");
 268        memcpy(drbg->prev, entropy, entropylen);
 269
 270        /* the test shall pass when the two values are not equal */
 271        return 0;
 272}
 273
 274/*
 275 * Convert an integer into a byte representation of this integer.
 276 * The byte representation is big-endian
 277 *
 278 * @val value to be converted
 279 * @buf buffer holding the converted integer -- caller must ensure that
 280 *      buffer size is at least 32 bit
 281 */
 282#if (defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR))
 283static inline void drbg_cpu_to_be32(__u32 val, unsigned char *buf)
 284{
 285        struct s {
 286                __be32 conv;
 287        };
 288        struct s *conversion = (struct s *) buf;
 289
 290        conversion->conv = cpu_to_be32(val);
 291}
 292#endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */
 293
 294/******************************************************************
 295 * CTR DRBG callback functions
 296 ******************************************************************/
 297
 298#ifdef CONFIG_CRYPTO_DRBG_CTR
 299#define CRYPTO_DRBG_CTR_STRING "CTR "
 300MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes256");
 301MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes256");
 302MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes192");
 303MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes192");
 304MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes128");
 305MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes128");
 306
 307static void drbg_kcapi_symsetkey(struct drbg_state *drbg,
 308                                 const unsigned char *key);
 309static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval,
 310                          const struct drbg_string *in);
 311static int drbg_init_sym_kernel(struct drbg_state *drbg);
 312static int drbg_fini_sym_kernel(struct drbg_state *drbg);
 313static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
 314                              u8 *inbuf, u32 inbuflen,
 315                              u8 *outbuf, u32 outlen);
 316#define DRBG_OUTSCRATCHLEN 256
 317
 318/* BCC function for CTR DRBG as defined in 10.4.3 */
 319static int drbg_ctr_bcc(struct drbg_state *drbg,
 320                        unsigned char *out, const unsigned char *key,
 321                        struct list_head *in)
 322{
 323        int ret = 0;
 324        struct drbg_string *curr = NULL;
 325        struct drbg_string data;
 326        short cnt = 0;
 327
 328        drbg_string_fill(&data, out, drbg_blocklen(drbg));
 329
 330        /* 10.4.3 step 2 / 4 */
 331        drbg_kcapi_symsetkey(drbg, key);
 332        list_for_each_entry(curr, in, list) {
 333                const unsigned char *pos = curr->buf;
 334                size_t len = curr->len;
 335                /* 10.4.3 step 4.1 */
 336                while (len) {
 337                        /* 10.4.3 step 4.2 */
 338                        if (drbg_blocklen(drbg) == cnt) {
 339                                cnt = 0;
 340                                ret = drbg_kcapi_sym(drbg, out, &data);
 341                                if (ret)
 342                                        return ret;
 343                        }
 344                        out[cnt] ^= *pos;
 345                        pos++;
 346                        cnt++;
 347                        len--;
 348                }
 349        }
 350        /* 10.4.3 step 4.2 for last block */
 351        if (cnt)
 352                ret = drbg_kcapi_sym(drbg, out, &data);
 353
 354        return ret;
 355}
 356
 357/*
 358 * scratchpad usage: drbg_ctr_update is interlinked with drbg_ctr_df
 359 * (and drbg_ctr_bcc, but this function does not need any temporary buffers),
 360 * the scratchpad is used as follows:
 361 * drbg_ctr_update:
 362 *      temp
 363 *              start: drbg->scratchpad
 364 *              length: drbg_statelen(drbg) + drbg_blocklen(drbg)
 365 *                      note: the cipher writing into this variable works
 366 *                      blocklen-wise. Now, when the statelen is not a multiple
 367 *                      of blocklen, the generateion loop below "spills over"
 368 *                      by at most blocklen. Thus, we need to give sufficient
 369 *                      memory.
 370 *      df_data
 371 *              start: drbg->scratchpad +
 372 *                              drbg_statelen(drbg) + drbg_blocklen(drbg)
 373 *              length: drbg_statelen(drbg)
 374 *
 375 * drbg_ctr_df:
 376 *      pad
 377 *              start: df_data + drbg_statelen(drbg)
 378 *              length: drbg_blocklen(drbg)
 379 *      iv
 380 *              start: pad + drbg_blocklen(drbg)
 381 *              length: drbg_blocklen(drbg)
 382 *      temp
 383 *              start: iv + drbg_blocklen(drbg)
 384 *              length: drbg_satelen(drbg) + drbg_blocklen(drbg)
 385 *                      note: temp is the buffer that the BCC function operates
 386 *                      on. BCC operates blockwise. drbg_statelen(drbg)
 387 *                      is sufficient when the DRBG state length is a multiple
 388 *                      of the block size. For AES192 (and maybe other ciphers)
 389 *                      this is not correct and the length for temp is
 390 *                      insufficient (yes, that also means for such ciphers,
 391 *                      the final output of all BCC rounds are truncated).
 392 *                      Therefore, add drbg_blocklen(drbg) to cover all
 393 *                      possibilities.
 394 */
 395
 396/* Derivation Function for CTR DRBG as defined in 10.4.2 */
 397static int drbg_ctr_df(struct drbg_state *drbg,
 398                       unsigned char *df_data, size_t bytes_to_return,
 399                       struct list_head *seedlist)
 400{
 401        int ret = -EFAULT;
 402        unsigned char L_N[8];
 403        /* S3 is input */
 404        struct drbg_string S1, S2, S4, cipherin;
 405        LIST_HEAD(bcc_list);
 406        unsigned char *pad = df_data + drbg_statelen(drbg);
 407        unsigned char *iv = pad + drbg_blocklen(drbg);
 408        unsigned char *temp = iv + drbg_blocklen(drbg);
 409        size_t padlen = 0;
 410        unsigned int templen = 0;
 411        /* 10.4.2 step 7 */
 412        unsigned int i = 0;
 413        /* 10.4.2 step 8 */
 414        const unsigned char *K = (unsigned char *)
 415                           "\x00\x01\x02\x03\x04\x05\x06\x07"
 416                           "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
 417                           "\x10\x11\x12\x13\x14\x15\x16\x17"
 418                           "\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f";
 419        unsigned char *X;
 420        size_t generated_len = 0;
 421        size_t inputlen = 0;
 422        struct drbg_string *seed = NULL;
 423
 424        memset(pad, 0, drbg_blocklen(drbg));
 425        memset(iv, 0, drbg_blocklen(drbg));
 426
 427        /* 10.4.2 step 1 is implicit as we work byte-wise */
 428
 429        /* 10.4.2 step 2 */
 430        if ((512/8) < bytes_to_return)
 431                return -EINVAL;
 432
 433        /* 10.4.2 step 2 -- calculate the entire length of all input data */
 434        list_for_each_entry(seed, seedlist, list)
 435                inputlen += seed->len;
 436        drbg_cpu_to_be32(inputlen, &L_N[0]);
 437
 438        /* 10.4.2 step 3 */
 439        drbg_cpu_to_be32(bytes_to_return, &L_N[4]);
 440
 441        /* 10.4.2 step 5: length is L_N, input_string, one byte, padding */
 442        padlen = (inputlen + sizeof(L_N) + 1) % (drbg_blocklen(drbg));
 443        /* wrap the padlen appropriately */
 444        if (padlen)
 445                padlen = drbg_blocklen(drbg) - padlen;
 446        /*
 447         * pad / padlen contains the 0x80 byte and the following zero bytes.
 448         * As the calculated padlen value only covers the number of zero
 449         * bytes, this value has to be incremented by one for the 0x80 byte.
 450         */
 451        padlen++;
 452        pad[0] = 0x80;
 453
 454        /* 10.4.2 step 4 -- first fill the linked list and then order it */
 455        drbg_string_fill(&S1, iv, drbg_blocklen(drbg));
 456        list_add_tail(&S1.list, &bcc_list);
 457        drbg_string_fill(&S2, L_N, sizeof(L_N));
 458        list_add_tail(&S2.list, &bcc_list);
 459        list_splice_tail(seedlist, &bcc_list);
 460        drbg_string_fill(&S4, pad, padlen);
 461        list_add_tail(&S4.list, &bcc_list);
 462
 463        /* 10.4.2 step 9 */
 464        while (templen < (drbg_keylen(drbg) + (drbg_blocklen(drbg)))) {
 465                /*
 466                 * 10.4.2 step 9.1 - the padding is implicit as the buffer
 467                 * holds zeros after allocation -- even the increment of i
 468                 * is irrelevant as the increment remains within length of i
 469                 */
 470                drbg_cpu_to_be32(i, iv);
 471                /* 10.4.2 step 9.2 -- BCC and concatenation with temp */
 472                ret = drbg_ctr_bcc(drbg, temp + templen, K, &bcc_list);
 473                if (ret)
 474                        goto out;
 475                /* 10.4.2 step 9.3 */
 476                i++;
 477                templen += drbg_blocklen(drbg);
 478        }
 479
 480        /* 10.4.2 step 11 */
 481        X = temp + (drbg_keylen(drbg));
 482        drbg_string_fill(&cipherin, X, drbg_blocklen(drbg));
 483
 484        /* 10.4.2 step 12: overwriting of outval is implemented in next step */
 485
 486        /* 10.4.2 step 13 */
 487        drbg_kcapi_symsetkey(drbg, temp);
 488        while (generated_len < bytes_to_return) {
 489                short blocklen = 0;
 490                /*
 491                 * 10.4.2 step 13.1: the truncation of the key length is
 492                 * implicit as the key is only drbg_blocklen in size based on
 493                 * the implementation of the cipher function callback
 494                 */
 495                ret = drbg_kcapi_sym(drbg, X, &cipherin);
 496                if (ret)
 497                        goto out;
 498                blocklen = (drbg_blocklen(drbg) <
 499                                (bytes_to_return - generated_len)) ?
 500                            drbg_blocklen(drbg) :
 501                                (bytes_to_return - generated_len);
 502                /* 10.4.2 step 13.2 and 14 */
 503                memcpy(df_data + generated_len, X, blocklen);
 504                generated_len += blocklen;
 505        }
 506
 507        ret = 0;
 508
 509out:
 510        memset(iv, 0, drbg_blocklen(drbg));
 511        memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
 512        memset(pad, 0, drbg_blocklen(drbg));
 513        return ret;
 514}
 515
 516/*
 517 * update function of CTR DRBG as defined in 10.2.1.2
 518 *
 519 * The reseed variable has an enhanced meaning compared to the update
 520 * functions of the other DRBGs as follows:
 521 * 0 => initial seed from initialization
 522 * 1 => reseed via drbg_seed
 523 * 2 => first invocation from drbg_ctr_update when addtl is present. In
 524 *      this case, the df_data scratchpad is not deleted so that it is
 525 *      available for another calls to prevent calling the DF function
 526 *      again.
 527 * 3 => second invocation from drbg_ctr_update. When the update function
 528 *      was called with addtl, the df_data memory already contains the
 529 *      DFed addtl information and we do not need to call DF again.
 530 */
 531static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed,
 532                           int reseed)
 533{
 534        int ret = -EFAULT;
 535        /* 10.2.1.2 step 1 */
 536        unsigned char *temp = drbg->scratchpad;
 537        unsigned char *df_data = drbg->scratchpad + drbg_statelen(drbg) +
 538                                 drbg_blocklen(drbg);
 539
 540        if (3 > reseed)
 541                memset(df_data, 0, drbg_statelen(drbg));
 542
 543        if (!reseed) {
 544                /*
 545                 * The DRBG uses the CTR mode of the underlying AES cipher. The
 546                 * CTR mode increments the counter value after the AES operation
 547                 * but SP800-90A requires that the counter is incremented before
 548                 * the AES operation. Hence, we increment it at the time we set
 549                 * it by one.
 550                 */
 551                crypto_inc(drbg->V, drbg_blocklen(drbg));
 552
 553                ret = crypto_skcipher_setkey(drbg->ctr_handle, drbg->C,
 554                                             drbg_keylen(drbg));
 555                if (ret)
 556                        goto out;
 557        }
 558
 559        /* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */
 560        if (seed) {
 561                ret = drbg_ctr_df(drbg, df_data, drbg_statelen(drbg), seed);
 562                if (ret)
 563                        goto out;
 564        }
 565
 566        ret = drbg_kcapi_sym_ctr(drbg, df_data, drbg_statelen(drbg),
 567                                 temp, drbg_statelen(drbg));
 568        if (ret)
 569                return ret;
 570
 571        /* 10.2.1.2 step 5 */
 572        ret = crypto_skcipher_setkey(drbg->ctr_handle, temp,
 573                                     drbg_keylen(drbg));
 574        if (ret)
 575                goto out;
 576        /* 10.2.1.2 step 6 */
 577        memcpy(drbg->V, temp + drbg_keylen(drbg), drbg_blocklen(drbg));
 578        /* See above: increment counter by one to compensate timing of CTR op */
 579        crypto_inc(drbg->V, drbg_blocklen(drbg));
 580        ret = 0;
 581
 582out:
 583        memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
 584        if (2 != reseed)
 585                memset(df_data, 0, drbg_statelen(drbg));
 586        return ret;
 587}
 588
 589/*
 590 * scratchpad use: drbg_ctr_update is called independently from
 591 * drbg_ctr_extract_bytes. Therefore, the scratchpad is reused
 592 */
 593/* Generate function of CTR DRBG as defined in 10.2.1.5.2 */
 594static int drbg_ctr_generate(struct drbg_state *drbg,
 595                             unsigned char *buf, unsigned int buflen,
 596                             struct list_head *addtl)
 597{
 598        int ret;
 599        int len = min_t(int, buflen, INT_MAX);
 600
 601        /* 10.2.1.5.2 step 2 */
 602        if (addtl && !list_empty(addtl)) {
 603                ret = drbg_ctr_update(drbg, addtl, 2);
 604                if (ret)
 605                        return 0;
 606        }
 607
 608        /* 10.2.1.5.2 step 4.1 */
 609        ret = drbg_kcapi_sym_ctr(drbg, NULL, 0, buf, len);
 610        if (ret)
 611                return ret;
 612
 613        /* 10.2.1.5.2 step 6 */
 614        ret = drbg_ctr_update(drbg, NULL, 3);
 615        if (ret)
 616                len = ret;
 617
 618        return len;
 619}
 620
 621static const struct drbg_state_ops drbg_ctr_ops = {
 622        .update         = drbg_ctr_update,
 623        .generate       = drbg_ctr_generate,
 624        .crypto_init    = drbg_init_sym_kernel,
 625        .crypto_fini    = drbg_fini_sym_kernel,
 626};
 627#endif /* CONFIG_CRYPTO_DRBG_CTR */
 628
 629/******************************************************************
 630 * HMAC DRBG callback functions
 631 ******************************************************************/
 632
 633#if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
 634static int drbg_kcapi_hash(struct drbg_state *drbg, unsigned char *outval,
 635                           const struct list_head *in);
 636static void drbg_kcapi_hmacsetkey(struct drbg_state *drbg,
 637                                  const unsigned char *key);
 638static int drbg_init_hash_kernel(struct drbg_state *drbg);
 639static int drbg_fini_hash_kernel(struct drbg_state *drbg);
 640#endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
 641
 642#ifdef CONFIG_CRYPTO_DRBG_HMAC
 643#define CRYPTO_DRBG_HMAC_STRING "HMAC "
 644MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha512");
 645MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha512");
 646MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha384");
 647MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha384");
 648MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha256");
 649MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha256");
 650MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha1");
 651MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha1");
 652
 653/* update function of HMAC DRBG as defined in 10.1.2.2 */
 654static int drbg_hmac_update(struct drbg_state *drbg, struct list_head *seed,
 655                            int reseed)
 656{
 657        int ret = -EFAULT;
 658        int i = 0;
 659        struct drbg_string seed1, seed2, vdata;
 660        LIST_HEAD(seedlist);
 661        LIST_HEAD(vdatalist);
 662
 663        if (!reseed) {
 664                /* 10.1.2.3 step 2 -- memset(0) of C is implicit with kzalloc */
 665                memset(drbg->V, 1, drbg_statelen(drbg));
 666                drbg_kcapi_hmacsetkey(drbg, drbg->C);
 667        }
 668
 669        drbg_string_fill(&seed1, drbg->V, drbg_statelen(drbg));
 670        list_add_tail(&seed1.list, &seedlist);
 671        /* buffer of seed2 will be filled in for loop below with one byte */
 672        drbg_string_fill(&seed2, NULL, 1);
 673        list_add_tail(&seed2.list, &seedlist);
 674        /* input data of seed is allowed to be NULL at this point */
 675        if (seed)
 676                list_splice_tail(seed, &seedlist);
 677
 678        drbg_string_fill(&vdata, drbg->V, drbg_statelen(drbg));
 679        list_add_tail(&vdata.list, &vdatalist);
 680        for (i = 2; 0 < i; i--) {
 681                /* first round uses 0x0, second 0x1 */
 682                unsigned char prefix = DRBG_PREFIX0;
 683                if (1 == i)
 684                        prefix = DRBG_PREFIX1;
 685                /* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */
 686                seed2.buf = &prefix;
 687                ret = drbg_kcapi_hash(drbg, drbg->C, &seedlist);
 688                if (ret)
 689                        return ret;
 690                drbg_kcapi_hmacsetkey(drbg, drbg->C);
 691
 692                /* 10.1.2.2 step 2 and 5 -- HMAC for V */
 693                ret = drbg_kcapi_hash(drbg, drbg->V, &vdatalist);
 694                if (ret)
 695                        return ret;
 696
 697                /* 10.1.2.2 step 3 */
 698                if (!seed)
 699                        return ret;
 700        }
 701
 702        return 0;
 703}
 704
 705/* generate function of HMAC DRBG as defined in 10.1.2.5 */
 706static int drbg_hmac_generate(struct drbg_state *drbg,
 707                              unsigned char *buf,
 708                              unsigned int buflen,
 709                              struct list_head *addtl)
 710{
 711        int len = 0;
 712        int ret = 0;
 713        struct drbg_string data;
 714        LIST_HEAD(datalist);
 715
 716        /* 10.1.2.5 step 2 */
 717        if (addtl && !list_empty(addtl)) {
 718                ret = drbg_hmac_update(drbg, addtl, 1);
 719                if (ret)
 720                        return ret;
 721        }
 722
 723        drbg_string_fill(&data, drbg->V, drbg_statelen(drbg));
 724        list_add_tail(&data.list, &datalist);
 725        while (len < buflen) {
 726                unsigned int outlen = 0;
 727                /* 10.1.2.5 step 4.1 */
 728                ret = drbg_kcapi_hash(drbg, drbg->V, &datalist);
 729                if (ret)
 730                        return ret;
 731                outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
 732                          drbg_blocklen(drbg) : (buflen - len);
 733
 734                /* 10.1.2.5 step 4.2 */
 735                memcpy(buf + len, drbg->V, outlen);
 736                len += outlen;
 737        }
 738
 739        /* 10.1.2.5 step 6 */
 740        if (addtl && !list_empty(addtl))
 741                ret = drbg_hmac_update(drbg, addtl, 1);
 742        else
 743                ret = drbg_hmac_update(drbg, NULL, 1);
 744        if (ret)
 745                return ret;
 746
 747        return len;
 748}
 749
 750static const struct drbg_state_ops drbg_hmac_ops = {
 751        .update         = drbg_hmac_update,
 752        .generate       = drbg_hmac_generate,
 753        .crypto_init    = drbg_init_hash_kernel,
 754        .crypto_fini    = drbg_fini_hash_kernel,
 755};
 756#endif /* CONFIG_CRYPTO_DRBG_HMAC */
 757
 758/******************************************************************
 759 * Hash DRBG callback functions
 760 ******************************************************************/
 761
 762#ifdef CONFIG_CRYPTO_DRBG_HASH
 763#define CRYPTO_DRBG_HASH_STRING "HASH "
 764MODULE_ALIAS_CRYPTO("drbg_pr_sha512");
 765MODULE_ALIAS_CRYPTO("drbg_nopr_sha512");
 766MODULE_ALIAS_CRYPTO("drbg_pr_sha384");
 767MODULE_ALIAS_CRYPTO("drbg_nopr_sha384");
 768MODULE_ALIAS_CRYPTO("drbg_pr_sha256");
 769MODULE_ALIAS_CRYPTO("drbg_nopr_sha256");
 770MODULE_ALIAS_CRYPTO("drbg_pr_sha1");
 771MODULE_ALIAS_CRYPTO("drbg_nopr_sha1");
 772
 773/*
 774 * Increment buffer
 775 *
 776 * @dst buffer to increment
 777 * @add value to add
 778 */
 779static inline void drbg_add_buf(unsigned char *dst, size_t dstlen,
 780                                const unsigned char *add, size_t addlen)
 781{
 782        /* implied: dstlen > addlen */
 783        unsigned char *dstptr;
 784        const unsigned char *addptr;
 785        unsigned int remainder = 0;
 786        size_t len = addlen;
 787
 788        dstptr = dst + (dstlen-1);
 789        addptr = add + (addlen-1);
 790        while (len) {
 791                remainder += *dstptr + *addptr;
 792                *dstptr = remainder & 0xff;
 793                remainder >>= 8;
 794                len--; dstptr--; addptr--;
 795        }
 796        len = dstlen - addlen;
 797        while (len && remainder > 0) {
 798                remainder = *dstptr + 1;
 799                *dstptr = remainder & 0xff;
 800                remainder >>= 8;
 801                len--; dstptr--;
 802        }
 803}
 804
 805/*
 806 * scratchpad usage: as drbg_hash_update and drbg_hash_df are used
 807 * interlinked, the scratchpad is used as follows:
 808 * drbg_hash_update
 809 *      start: drbg->scratchpad
 810 *      length: drbg_statelen(drbg)
 811 * drbg_hash_df:
 812 *      start: drbg->scratchpad + drbg_statelen(drbg)
 813 *      length: drbg_blocklen(drbg)
 814 *
 815 * drbg_hash_process_addtl uses the scratchpad, but fully completes
 816 * before either of the functions mentioned before are invoked. Therefore,
 817 * drbg_hash_process_addtl does not need to be specifically considered.
 818 */
 819
 820/* Derivation Function for Hash DRBG as defined in 10.4.1 */
 821static int drbg_hash_df(struct drbg_state *drbg,
 822                        unsigned char *outval, size_t outlen,
 823                        struct list_head *entropylist)
 824{
 825        int ret = 0;
 826        size_t len = 0;
 827        unsigned char input[5];
 828        unsigned char *tmp = drbg->scratchpad + drbg_statelen(drbg);
 829        struct drbg_string data;
 830
 831        /* 10.4.1 step 3 */
 832        input[0] = 1;
 833        drbg_cpu_to_be32((outlen * 8), &input[1]);
 834
 835        /* 10.4.1 step 4.1 -- concatenation of data for input into hash */
 836        drbg_string_fill(&data, input, 5);
 837        list_add(&data.list, entropylist);
 838
 839        /* 10.4.1 step 4 */
 840        while (len < outlen) {
 841                short blocklen = 0;
 842                /* 10.4.1 step 4.1 */
 843                ret = drbg_kcapi_hash(drbg, tmp, entropylist);
 844                if (ret)
 845                        goto out;
 846                /* 10.4.1 step 4.2 */
 847                input[0]++;
 848                blocklen = (drbg_blocklen(drbg) < (outlen - len)) ?
 849                            drbg_blocklen(drbg) : (outlen - len);
 850                memcpy(outval + len, tmp, blocklen);
 851                len += blocklen;
 852        }
 853
 854out:
 855        memset(tmp, 0, drbg_blocklen(drbg));
 856        return ret;
 857}
 858
 859/* update function for Hash DRBG as defined in 10.1.1.2 / 10.1.1.3 */
 860static int drbg_hash_update(struct drbg_state *drbg, struct list_head *seed,
 861                            int reseed)
 862{
 863        int ret = 0;
 864        struct drbg_string data1, data2;
 865        LIST_HEAD(datalist);
 866        LIST_HEAD(datalist2);
 867        unsigned char *V = drbg->scratchpad;
 868        unsigned char prefix = DRBG_PREFIX1;
 869
 870        if (!seed)
 871                return -EINVAL;
 872
 873        if (reseed) {
 874                /* 10.1.1.3 step 1 */
 875                memcpy(V, drbg->V, drbg_statelen(drbg));
 876                drbg_string_fill(&data1, &prefix, 1);
 877                list_add_tail(&data1.list, &datalist);
 878                drbg_string_fill(&data2, V, drbg_statelen(drbg));
 879                list_add_tail(&data2.list, &datalist);
 880        }
 881        list_splice_tail(seed, &datalist);
 882
 883        /* 10.1.1.2 / 10.1.1.3 step 2 and 3 */
 884        ret = drbg_hash_df(drbg, drbg->V, drbg_statelen(drbg), &datalist);
 885        if (ret)
 886                goto out;
 887
 888        /* 10.1.1.2 / 10.1.1.3 step 4  */
 889        prefix = DRBG_PREFIX0;
 890        drbg_string_fill(&data1, &prefix, 1);
 891        list_add_tail(&data1.list, &datalist2);
 892        drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
 893        list_add_tail(&data2.list, &datalist2);
 894        /* 10.1.1.2 / 10.1.1.3 step 4 */
 895        ret = drbg_hash_df(drbg, drbg->C, drbg_statelen(drbg), &datalist2);
 896
 897out:
 898        memset(drbg->scratchpad, 0, drbg_statelen(drbg));
 899        return ret;
 900}
 901
 902/* processing of additional information string for Hash DRBG */
 903static int drbg_hash_process_addtl(struct drbg_state *drbg,
 904                                   struct list_head *addtl)
 905{
 906        int ret = 0;
 907        struct drbg_string data1, data2;
 908        LIST_HEAD(datalist);
 909        unsigned char prefix = DRBG_PREFIX2;
 910
 911        /* 10.1.1.4 step 2 */
 912        if (!addtl || list_empty(addtl))
 913                return 0;
 914
 915        /* 10.1.1.4 step 2a */
 916        drbg_string_fill(&data1, &prefix, 1);
 917        drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
 918        list_add_tail(&data1.list, &datalist);
 919        list_add_tail(&data2.list, &datalist);
 920        list_splice_tail(addtl, &datalist);
 921        ret = drbg_kcapi_hash(drbg, drbg->scratchpad, &datalist);
 922        if (ret)
 923                goto out;
 924
 925        /* 10.1.1.4 step 2b */
 926        drbg_add_buf(drbg->V, drbg_statelen(drbg),
 927                     drbg->scratchpad, drbg_blocklen(drbg));
 928
 929out:
 930        memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
 931        return ret;
 932}
 933
 934/* Hashgen defined in 10.1.1.4 */
 935static int drbg_hash_hashgen(struct drbg_state *drbg,
 936                             unsigned char *buf,
 937                             unsigned int buflen)
 938{
 939        int len = 0;
 940        int ret = 0;
 941        unsigned char *src = drbg->scratchpad;
 942        unsigned char *dst = drbg->scratchpad + drbg_statelen(drbg);
 943        struct drbg_string data;
 944        LIST_HEAD(datalist);
 945
 946        /* 10.1.1.4 step hashgen 2 */
 947        memcpy(src, drbg->V, drbg_statelen(drbg));
 948
 949        drbg_string_fill(&data, src, drbg_statelen(drbg));
 950        list_add_tail(&data.list, &datalist);
 951        while (len < buflen) {
 952                unsigned int outlen = 0;
 953                /* 10.1.1.4 step hashgen 4.1 */
 954                ret = drbg_kcapi_hash(drbg, dst, &datalist);
 955                if (ret) {
 956                        len = ret;
 957                        goto out;
 958                }
 959                outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
 960                          drbg_blocklen(drbg) : (buflen - len);
 961                /* 10.1.1.4 step hashgen 4.2 */
 962                memcpy(buf + len, dst, outlen);
 963                len += outlen;
 964                /* 10.1.1.4 hashgen step 4.3 */
 965                if (len < buflen)
 966                        crypto_inc(src, drbg_statelen(drbg));
 967        }
 968
 969out:
 970        memset(drbg->scratchpad, 0,
 971               (drbg_statelen(drbg) + drbg_blocklen(drbg)));
 972        return len;
 973}
 974
 975/* generate function for Hash DRBG as defined in  10.1.1.4 */
 976static int drbg_hash_generate(struct drbg_state *drbg,
 977                              unsigned char *buf, unsigned int buflen,
 978                              struct list_head *addtl)
 979{
 980        int len = 0;
 981        int ret = 0;
 982        union {
 983                unsigned char req[8];
 984                __be64 req_int;
 985        } u;
 986        unsigned char prefix = DRBG_PREFIX3;
 987        struct drbg_string data1, data2;
 988        LIST_HEAD(datalist);
 989
 990        /* 10.1.1.4 step 2 */
 991        ret = drbg_hash_process_addtl(drbg, addtl);
 992        if (ret)
 993                return ret;
 994        /* 10.1.1.4 step 3 */
 995        len = drbg_hash_hashgen(drbg, buf, buflen);
 996
 997        /* this is the value H as documented in 10.1.1.4 */
 998        /* 10.1.1.4 step 4 */
 999        drbg_string_fill(&data1, &prefix, 1);
1000        list_add_tail(&data1.list, &datalist);
1001        drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
1002        list_add_tail(&data2.list, &datalist);
1003        ret = drbg_kcapi_hash(drbg, drbg->scratchpad, &datalist);
1004        if (ret) {
1005                len = ret;
1006                goto out;
1007        }
1008
1009        /* 10.1.1.4 step 5 */
1010        drbg_add_buf(drbg->V, drbg_statelen(drbg),
1011                     drbg->scratchpad, drbg_blocklen(drbg));
1012        drbg_add_buf(drbg->V, drbg_statelen(drbg),
1013                     drbg->C, drbg_statelen(drbg));
1014        u.req_int = cpu_to_be64(drbg->reseed_ctr);
1015        drbg_add_buf(drbg->V, drbg_statelen(drbg), u.req, 8);
1016
1017out:
1018        memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
1019        return len;
1020}
1021
1022/*
1023 * scratchpad usage: as update and generate are used isolated, both
1024 * can use the scratchpad
1025 */
1026static const struct drbg_state_ops drbg_hash_ops = {
1027        .update         = drbg_hash_update,
1028        .generate       = drbg_hash_generate,
1029        .crypto_init    = drbg_init_hash_kernel,
1030        .crypto_fini    = drbg_fini_hash_kernel,
1031};
1032#endif /* CONFIG_CRYPTO_DRBG_HASH */
1033
1034/******************************************************************
1035 * Functions common for DRBG implementations
1036 ******************************************************************/
1037
1038static inline int __drbg_seed(struct drbg_state *drbg, struct list_head *seed,
1039                              int reseed)
1040{
1041        int ret = drbg->d_ops->update(drbg, seed, reseed);
1042
1043        if (ret)
1044                return ret;
1045
1046        drbg->seeded = true;
1047        /* 10.1.1.2 / 10.1.1.3 step 5 */
1048        drbg->reseed_ctr = 1;
1049
1050        return ret;
1051}
1052
1053static inline int drbg_get_random_bytes(struct drbg_state *drbg,
1054                                        unsigned char *entropy,
1055                                        unsigned int entropylen)
1056{
1057        int ret;
1058
1059        do {
1060                get_random_bytes(entropy, entropylen);
1061                ret = drbg_fips_continuous_test(drbg, entropy);
1062                if (ret && ret != -EAGAIN)
1063                        return ret;
1064        } while (ret);
1065
1066        return 0;
1067}
1068
1069static void drbg_async_seed(struct work_struct *work)
1070{
1071        struct drbg_string data;
1072        LIST_HEAD(seedlist);
1073        struct drbg_state *drbg = container_of(work, struct drbg_state,
1074                                               seed_work);
1075        unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
1076        unsigned char entropy[32];
1077        int ret;
1078
1079        BUG_ON(!entropylen);
1080        BUG_ON(entropylen > sizeof(entropy));
1081
1082        drbg_string_fill(&data, entropy, entropylen);
1083        list_add_tail(&data.list, &seedlist);
1084
1085        mutex_lock(&drbg->drbg_mutex);
1086
1087        ret = drbg_get_random_bytes(drbg, entropy, entropylen);
1088        if (ret)
1089                goto unlock;
1090
1091        /* Set seeded to false so that if __drbg_seed fails the
1092         * next generate call will trigger a reseed.
1093         */
1094        drbg->seeded = false;
1095
1096        __drbg_seed(drbg, &seedlist, true);
1097
1098        if (drbg->seeded)
1099                drbg->reseed_threshold = drbg_max_requests(drbg);
1100
1101unlock:
1102        mutex_unlock(&drbg->drbg_mutex);
1103
1104        memzero_explicit(entropy, entropylen);
1105}
1106
1107/*
1108 * Seeding or reseeding of the DRBG
1109 *
1110 * @drbg: DRBG state struct
1111 * @pers: personalization / additional information buffer
1112 * @reseed: 0 for initial seed process, 1 for reseeding
1113 *
1114 * return:
1115 *      0 on success
1116 *      error value otherwise
1117 */
1118static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
1119                     bool reseed)
1120{
1121        int ret;
1122        unsigned char entropy[((32 + 16) * 2)];
1123        unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
1124        struct drbg_string data1;
1125        LIST_HEAD(seedlist);
1126
1127        /* 9.1 / 9.2 / 9.3.1 step 3 */
1128        if (pers && pers->len > (drbg_max_addtl(drbg))) {
1129                pr_devel("DRBG: personalization string too long %zu\n",
1130                         pers->len);
1131                return -EINVAL;
1132        }
1133
1134        if (list_empty(&drbg->test_data.list)) {
1135                drbg_string_fill(&data1, drbg->test_data.buf,
1136                                 drbg->test_data.len);
1137                pr_devel("DRBG: using test entropy\n");
1138        } else {
1139                /*
1140                 * Gather entropy equal to the security strength of the DRBG.
1141                 * With a derivation function, a nonce is required in addition
1142                 * to the entropy. A nonce must be at least 1/2 of the security
1143                 * strength of the DRBG in size. Thus, entropy + nonce is 3/2
1144                 * of the strength. The consideration of a nonce is only
1145                 * applicable during initial seeding.
1146                 */
1147                BUG_ON(!entropylen);
1148                if (!reseed)
1149                        entropylen = ((entropylen + 1) / 2) * 3;
1150                BUG_ON((entropylen * 2) > sizeof(entropy));
1151
1152                /* Get seed from in-kernel /dev/urandom */
1153                ret = drbg_get_random_bytes(drbg, entropy, entropylen);
1154                if (ret)
1155                        goto out;
1156
1157                if (!drbg->jent) {
1158                        drbg_string_fill(&data1, entropy, entropylen);
1159                        pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
1160                                 entropylen);
1161                } else {
1162                        /* Get seed from Jitter RNG */
1163                        ret = crypto_rng_get_bytes(drbg->jent,
1164                                                   entropy + entropylen,
1165                                                   entropylen);
1166                        if (ret) {
1167                                pr_devel("DRBG: jent failed with %d\n", ret);
1168
1169                                /*
1170                                 * Do not treat the transient failure of the
1171                                 * Jitter RNG as an error that needs to be
1172                                 * reported. The combined number of the
1173                                 * maximum reseed threshold times the maximum
1174                                 * number of Jitter RNG transient errors is
1175                                 * less than the reseed threshold required by
1176                                 * SP800-90A allowing us to treat the
1177                                 * transient errors as such.
1178                                 *
1179                                 * However, we mandate that at least the first
1180                                 * seeding operation must succeed with the
1181                                 * Jitter RNG.
1182                                 */
1183                                if (!reseed || ret != -EAGAIN)
1184                                        goto out;
1185                        }
1186
1187                        drbg_string_fill(&data1, entropy, entropylen * 2);
1188                        pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
1189                                 entropylen * 2);
1190                }
1191        }
1192        list_add_tail(&data1.list, &seedlist);
1193
1194        /*
1195         * concatenation of entropy with personalization str / addtl input)
1196         * the variable pers is directly handed in by the caller, so check its
1197         * contents whether it is appropriate
1198         */
1199        if (pers && pers->buf && 0 < pers->len) {
1200                list_add_tail(&pers->list, &seedlist);
1201                pr_devel("DRBG: using personalization string\n");
1202        }
1203
1204        if (!reseed) {
1205                memset(drbg->V, 0, drbg_statelen(drbg));
1206                memset(drbg->C, 0, drbg_statelen(drbg));
1207        }
1208
1209        ret = __drbg_seed(drbg, &seedlist, reseed);
1210
1211out:
1212        memzero_explicit(entropy, entropylen * 2);
1213
1214        return ret;
1215}
1216
1217/* Free all substructures in a DRBG state without the DRBG state structure */
1218static inline void drbg_dealloc_state(struct drbg_state *drbg)
1219{
1220        if (!drbg)
1221                return;
1222        kfree_sensitive(drbg->Vbuf);
1223        drbg->Vbuf = NULL;
1224        drbg->V = NULL;
1225        kfree_sensitive(drbg->Cbuf);
1226        drbg->Cbuf = NULL;
1227        drbg->C = NULL;
1228        kfree_sensitive(drbg->scratchpadbuf);
1229        drbg->scratchpadbuf = NULL;
1230        drbg->reseed_ctr = 0;
1231        drbg->d_ops = NULL;
1232        drbg->core = NULL;
1233        if (IS_ENABLED(CONFIG_CRYPTO_FIPS)) {
1234                kfree_sensitive(drbg->prev);
1235                drbg->prev = NULL;
1236                drbg->fips_primed = false;
1237        }
1238}
1239
1240/*
1241 * Allocate all sub-structures for a DRBG state.
1242 * The DRBG state structure must already be allocated.
1243 */
1244static inline int drbg_alloc_state(struct drbg_state *drbg)
1245{
1246        int ret = -ENOMEM;
1247        unsigned int sb_size = 0;
1248
1249        switch (drbg->core->flags & DRBG_TYPE_MASK) {
1250#ifdef CONFIG_CRYPTO_DRBG_HMAC
1251        case DRBG_HMAC:
1252                drbg->d_ops = &drbg_hmac_ops;
1253                break;
1254#endif /* CONFIG_CRYPTO_DRBG_HMAC */
1255#ifdef CONFIG_CRYPTO_DRBG_HASH
1256        case DRBG_HASH:
1257                drbg->d_ops = &drbg_hash_ops;
1258                break;
1259#endif /* CONFIG_CRYPTO_DRBG_HASH */
1260#ifdef CONFIG_CRYPTO_DRBG_CTR
1261        case DRBG_CTR:
1262                drbg->d_ops = &drbg_ctr_ops;
1263                break;
1264#endif /* CONFIG_CRYPTO_DRBG_CTR */
1265        default:
1266                ret = -EOPNOTSUPP;
1267                goto err;
1268        }
1269
1270        ret = drbg->d_ops->crypto_init(drbg);
1271        if (ret < 0)
1272                goto err;
1273
1274        drbg->Vbuf = kmalloc(drbg_statelen(drbg) + ret, GFP_KERNEL);
1275        if (!drbg->Vbuf) {
1276                ret = -ENOMEM;
1277                goto fini;
1278        }
1279        drbg->V = PTR_ALIGN(drbg->Vbuf, ret + 1);
1280        drbg->Cbuf = kmalloc(drbg_statelen(drbg) + ret, GFP_KERNEL);
1281        if (!drbg->Cbuf) {
1282                ret = -ENOMEM;
1283                goto fini;
1284        }
1285        drbg->C = PTR_ALIGN(drbg->Cbuf, ret + 1);
1286        /* scratchpad is only generated for CTR and Hash */
1287        if (drbg->core->flags & DRBG_HMAC)
1288                sb_size = 0;
1289        else if (drbg->core->flags & DRBG_CTR)
1290                sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg) + /* temp */
1291                          drbg_statelen(drbg) + /* df_data */
1292                          drbg_blocklen(drbg) + /* pad */
1293                          drbg_blocklen(drbg) + /* iv */
1294                          drbg_statelen(drbg) + drbg_blocklen(drbg); /* temp */
1295        else
1296                sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg);
1297
1298        if (0 < sb_size) {
1299                drbg->scratchpadbuf = kzalloc(sb_size + ret, GFP_KERNEL);
1300                if (!drbg->scratchpadbuf) {
1301                        ret = -ENOMEM;
1302                        goto fini;
1303                }
1304                drbg->scratchpad = PTR_ALIGN(drbg->scratchpadbuf, ret + 1);
1305        }
1306
1307        if (IS_ENABLED(CONFIG_CRYPTO_FIPS)) {
1308                drbg->prev = kzalloc(drbg_sec_strength(drbg->core->flags),
1309                                     GFP_KERNEL);
1310                if (!drbg->prev) {
1311                        ret = -ENOMEM;
1312                        goto fini;
1313                }
1314                drbg->fips_primed = false;
1315        }
1316
1317        return 0;
1318
1319fini:
1320        drbg->d_ops->crypto_fini(drbg);
1321err:
1322        drbg_dealloc_state(drbg);
1323        return ret;
1324}
1325
1326/*************************************************************************
1327 * DRBG interface functions
1328 *************************************************************************/
1329
1330/*
1331 * DRBG generate function as required by SP800-90A - this function
1332 * generates random numbers
1333 *
1334 * @drbg DRBG state handle
1335 * @buf Buffer where to store the random numbers -- the buffer must already
1336 *      be pre-allocated by caller
1337 * @buflen Length of output buffer - this value defines the number of random
1338 *         bytes pulled from DRBG
1339 * @addtl Additional input that is mixed into state, may be NULL -- note
1340 *        the entropy is pulled by the DRBG internally unconditionally
1341 *        as defined in SP800-90A. The additional input is mixed into
1342 *        the state in addition to the pulled entropy.
1343 *
1344 * return: 0 when all bytes are generated; < 0 in case of an error
1345 */
1346static int drbg_generate(struct drbg_state *drbg,
1347                         unsigned char *buf, unsigned int buflen,
1348                         struct drbg_string *addtl)
1349{
1350        int len = 0;
1351        LIST_HEAD(addtllist);
1352
1353        if (!drbg->core) {
1354                pr_devel("DRBG: not yet seeded\n");
1355                return -EINVAL;
1356        }
1357        if (0 == buflen || !buf) {
1358                pr_devel("DRBG: no output buffer provided\n");
1359                return -EINVAL;
1360        }
1361        if (addtl && NULL == addtl->buf && 0 < addtl->len) {
1362                pr_devel("DRBG: wrong format of additional information\n");
1363                return -EINVAL;
1364        }
1365
1366        /* 9.3.1 step 2 */
1367        len = -EINVAL;
1368        if (buflen > (drbg_max_request_bytes(drbg))) {
1369                pr_devel("DRBG: requested random numbers too large %u\n",
1370                         buflen);
1371                goto err;
1372        }
1373
1374        /* 9.3.1 step 3 is implicit with the chosen DRBG */
1375
1376        /* 9.3.1 step 4 */
1377        if (addtl && addtl->len > (drbg_max_addtl(drbg))) {
1378                pr_devel("DRBG: additional information string too long %zu\n",
1379                         addtl->len);
1380                goto err;
1381        }
1382        /* 9.3.1 step 5 is implicit with the chosen DRBG */
1383
1384        /*
1385         * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented
1386         * here. The spec is a bit convoluted here, we make it simpler.
1387         */
1388        if (drbg->reseed_threshold < drbg->reseed_ctr)
1389                drbg->seeded = false;
1390
1391        if (drbg->pr || !drbg->seeded) {
1392                pr_devel("DRBG: reseeding before generation (prediction "
1393                         "resistance: %s, state %s)\n",
1394                         drbg->pr ? "true" : "false",
1395                         drbg->seeded ? "seeded" : "unseeded");
1396                /* 9.3.1 steps 7.1 through 7.3 */
1397                len = drbg_seed(drbg, addtl, true);
1398                if (len)
1399                        goto err;
1400                /* 9.3.1 step 7.4 */
1401                addtl = NULL;
1402        }
1403
1404        if (addtl && 0 < addtl->len)
1405                list_add_tail(&addtl->list, &addtllist);
1406        /* 9.3.1 step 8 and 10 */
1407        len = drbg->d_ops->generate(drbg, buf, buflen, &addtllist);
1408
1409        /* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */
1410        drbg->reseed_ctr++;
1411        if (0 >= len)
1412                goto err;
1413
1414        /*
1415         * Section 11.3.3 requires to re-perform self tests after some
1416         * generated random numbers. The chosen value after which self
1417         * test is performed is arbitrary, but it should be reasonable.
1418         * However, we do not perform the self tests because of the following
1419         * reasons: it is mathematically impossible that the initial self tests
1420         * were successfully and the following are not. If the initial would
1421         * pass and the following would not, the kernel integrity is violated.
1422         * In this case, the entire kernel operation is questionable and it
1423         * is unlikely that the integrity violation only affects the
1424         * correct operation of the DRBG.
1425         *
1426         * Albeit the following code is commented out, it is provided in
1427         * case somebody has a need to implement the test of 11.3.3.
1428         */
1429#if 0
1430        if (drbg->reseed_ctr && !(drbg->reseed_ctr % 4096)) {
1431                int err = 0;
1432                pr_devel("DRBG: start to perform self test\n");
1433                if (drbg->core->flags & DRBG_HMAC)
1434                        err = alg_test("drbg_pr_hmac_sha256",
1435                                       "drbg_pr_hmac_sha256", 0, 0);
1436                else if (drbg->core->flags & DRBG_CTR)
1437                        err = alg_test("drbg_pr_ctr_aes128",
1438                                       "drbg_pr_ctr_aes128", 0, 0);
1439                else
1440                        err = alg_test("drbg_pr_sha256",
1441                                       "drbg_pr_sha256", 0, 0);
1442                if (err) {
1443                        pr_err("DRBG: periodical self test failed\n");
1444                        /*
1445                         * uninstantiate implies that from now on, only errors
1446                         * are returned when reusing this DRBG cipher handle
1447                         */
1448                        drbg_uninstantiate(drbg);
1449                        return 0;
1450                } else {
1451                        pr_devel("DRBG: self test successful\n");
1452                }
1453        }
1454#endif
1455
1456        /*
1457         * All operations were successful, return 0 as mandated by
1458         * the kernel crypto API interface.
1459         */
1460        len = 0;
1461err:
1462        return len;
1463}
1464
1465/*
1466 * Wrapper around drbg_generate which can pull arbitrary long strings
1467 * from the DRBG without hitting the maximum request limitation.
1468 *
1469 * Parameters: see drbg_generate
1470 * Return codes: see drbg_generate -- if one drbg_generate request fails,
1471 *               the entire drbg_generate_long request fails
1472 */
1473static int drbg_generate_long(struct drbg_state *drbg,
1474                              unsigned char *buf, unsigned int buflen,
1475                              struct drbg_string *addtl)
1476{
1477        unsigned int len = 0;
1478        unsigned int slice = 0;
1479        do {
1480                int err = 0;
1481                unsigned int chunk = 0;
1482                slice = ((buflen - len) / drbg_max_request_bytes(drbg));
1483                chunk = slice ? drbg_max_request_bytes(drbg) : (buflen - len);
1484                mutex_lock(&drbg->drbg_mutex);
1485                err = drbg_generate(drbg, buf + len, chunk, addtl);
1486                mutex_unlock(&drbg->drbg_mutex);
1487                if (0 > err)
1488                        return err;
1489                len += chunk;
1490        } while (slice > 0 && (len < buflen));
1491        return 0;
1492}
1493
1494static void drbg_schedule_async_seed(struct random_ready_callback *rdy)
1495{
1496        struct drbg_state *drbg = container_of(rdy, struct drbg_state,
1497                                               random_ready);
1498
1499        schedule_work(&drbg->seed_work);
1500}
1501
1502static int drbg_prepare_hrng(struct drbg_state *drbg)
1503{
1504        int err;
1505
1506        /* We do not need an HRNG in test mode. */
1507        if (list_empty(&drbg->test_data.list))
1508                return 0;
1509
1510        drbg->jent = crypto_alloc_rng("jitterentropy_rng", 0, 0);
1511
1512        INIT_WORK(&drbg->seed_work, drbg_async_seed);
1513
1514        drbg->random_ready.owner = THIS_MODULE;
1515        drbg->random_ready.func = drbg_schedule_async_seed;
1516
1517        err = add_random_ready_callback(&drbg->random_ready);
1518
1519        switch (err) {
1520        case 0:
1521                break;
1522
1523        case -EALREADY:
1524                err = 0;
1525                fallthrough;
1526
1527        default:
1528                drbg->random_ready.func = NULL;
1529                return err;
1530        }
1531
1532        /*
1533         * Require frequent reseeds until the seed source is fully
1534         * initialized.
1535         */
1536        drbg->reseed_threshold = 50;
1537
1538        return err;
1539}
1540
1541/*
1542 * DRBG instantiation function as required by SP800-90A - this function
1543 * sets up the DRBG handle, performs the initial seeding and all sanity
1544 * checks required by SP800-90A
1545 *
1546 * @drbg memory of state -- if NULL, new memory is allocated
1547 * @pers Personalization string that is mixed into state, may be NULL -- note
1548 *       the entropy is pulled by the DRBG internally unconditionally
1549 *       as defined in SP800-90A. The additional input is mixed into
1550 *       the state in addition to the pulled entropy.
1551 * @coreref reference to core
1552 * @pr prediction resistance enabled
1553 *
1554 * return
1555 *      0 on success
1556 *      error value otherwise
1557 */
1558static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers,
1559                            int coreref, bool pr)
1560{
1561        int ret;
1562        bool reseed = true;
1563
1564        pr_devel("DRBG: Initializing DRBG core %d with prediction resistance "
1565                 "%s\n", coreref, pr ? "enabled" : "disabled");
1566        mutex_lock(&drbg->drbg_mutex);
1567
1568        /* 9.1 step 1 is implicit with the selected DRBG type */
1569
1570        /*
1571         * 9.1 step 2 is implicit as caller can select prediction resistance
1572         * and the flag is copied into drbg->flags --
1573         * all DRBG types support prediction resistance
1574         */
1575
1576        /* 9.1 step 4 is implicit in  drbg_sec_strength */
1577
1578        if (!drbg->core) {
1579                drbg->core = &drbg_cores[coreref];
1580                drbg->pr = pr;
1581                drbg->seeded = false;
1582                drbg->reseed_threshold = drbg_max_requests(drbg);
1583
1584                ret = drbg_alloc_state(drbg);
1585                if (ret)
1586                        goto unlock;
1587
1588                ret = drbg_prepare_hrng(drbg);
1589                if (ret)
1590                        goto free_everything;
1591
1592                if (IS_ERR(drbg->jent)) {
1593                        ret = PTR_ERR(drbg->jent);
1594                        drbg->jent = NULL;
1595                        if (fips_enabled || ret != -ENOENT)
1596                                goto free_everything;
1597                        pr_info("DRBG: Continuing without Jitter RNG\n");
1598                }
1599
1600                reseed = false;
1601        }
1602
1603        ret = drbg_seed(drbg, pers, reseed);
1604
1605        if (ret && !reseed)
1606                goto free_everything;
1607
1608        mutex_unlock(&drbg->drbg_mutex);
1609        return ret;
1610
1611unlock:
1612        mutex_unlock(&drbg->drbg_mutex);
1613        return ret;
1614
1615free_everything:
1616        mutex_unlock(&drbg->drbg_mutex);
1617        drbg_uninstantiate(drbg);
1618        return ret;
1619}
1620
1621/*
1622 * DRBG uninstantiate function as required by SP800-90A - this function
1623 * frees all buffers and the DRBG handle
1624 *
1625 * @drbg DRBG state handle
1626 *
1627 * return
1628 *      0 on success
1629 */
1630static int drbg_uninstantiate(struct drbg_state *drbg)
1631{
1632        if (drbg->random_ready.func) {
1633                del_random_ready_callback(&drbg->random_ready);
1634                cancel_work_sync(&drbg->seed_work);
1635        }
1636
1637        if (!IS_ERR_OR_NULL(drbg->jent))
1638                crypto_free_rng(drbg->jent);
1639        drbg->jent = NULL;
1640
1641        if (drbg->d_ops)
1642                drbg->d_ops->crypto_fini(drbg);
1643        drbg_dealloc_state(drbg);
1644        /* no scrubbing of test_data -- this shall survive an uninstantiate */
1645        return 0;
1646}
1647
1648/*
1649 * Helper function for setting the test data in the DRBG
1650 *
1651 * @drbg DRBG state handle
1652 * @data test data
1653 * @len test data length
1654 */
1655static void drbg_kcapi_set_entropy(struct crypto_rng *tfm,
1656                                   const u8 *data, unsigned int len)
1657{
1658        struct drbg_state *drbg = crypto_rng_ctx(tfm);
1659
1660        mutex_lock(&drbg->drbg_mutex);
1661        drbg_string_fill(&drbg->test_data, data, len);
1662        mutex_unlock(&drbg->drbg_mutex);
1663}
1664
1665/***************************************************************
1666 * Kernel crypto API cipher invocations requested by DRBG
1667 ***************************************************************/
1668
1669#if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
1670struct sdesc {
1671        struct shash_desc shash;
1672        char ctx[];
1673};
1674
1675static int drbg_init_hash_kernel(struct drbg_state *drbg)
1676{
1677        struct sdesc *sdesc;
1678        struct crypto_shash *tfm;
1679
1680        tfm = crypto_alloc_shash(drbg->core->backend_cra_name, 0, 0);
1681        if (IS_ERR(tfm)) {
1682                pr_info("DRBG: could not allocate digest TFM handle: %s\n",
1683                                drbg->core->backend_cra_name);
1684                return PTR_ERR(tfm);
1685        }
1686        BUG_ON(drbg_blocklen(drbg) != crypto_shash_digestsize(tfm));
1687        sdesc = kzalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm),
1688                        GFP_KERNEL);
1689        if (!sdesc) {
1690                crypto_free_shash(tfm);
1691                return -ENOMEM;
1692        }
1693
1694        sdesc->shash.tfm = tfm;
1695        drbg->priv_data = sdesc;
1696
1697        return crypto_shash_alignmask(tfm);
1698}
1699
1700static int drbg_fini_hash_kernel(struct drbg_state *drbg)
1701{
1702        struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
1703        if (sdesc) {
1704                crypto_free_shash(sdesc->shash.tfm);
1705                kfree_sensitive(sdesc);
1706        }
1707        drbg->priv_data = NULL;
1708        return 0;
1709}
1710
1711static void drbg_kcapi_hmacsetkey(struct drbg_state *drbg,
1712                                  const unsigned char *key)
1713{
1714        struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
1715
1716        crypto_shash_setkey(sdesc->shash.tfm, key, drbg_statelen(drbg));
1717}
1718
1719static int drbg_kcapi_hash(struct drbg_state *drbg, unsigned char *outval,
1720                           const struct list_head *in)
1721{
1722        struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
1723        struct drbg_string *input = NULL;
1724
1725        crypto_shash_init(&sdesc->shash);
1726        list_for_each_entry(input, in, list)
1727                crypto_shash_update(&sdesc->shash, input->buf, input->len);
1728        return crypto_shash_final(&sdesc->shash, outval);
1729}
1730#endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
1731
1732#ifdef CONFIG_CRYPTO_DRBG_CTR
1733static int drbg_fini_sym_kernel(struct drbg_state *drbg)
1734{
1735        struct crypto_cipher *tfm =
1736                (struct crypto_cipher *)drbg->priv_data;
1737        if (tfm)
1738                crypto_free_cipher(tfm);
1739        drbg->priv_data = NULL;
1740
1741        if (drbg->ctr_handle)
1742                crypto_free_skcipher(drbg->ctr_handle);
1743        drbg->ctr_handle = NULL;
1744
1745        if (drbg->ctr_req)
1746                skcipher_request_free(drbg->ctr_req);
1747        drbg->ctr_req = NULL;
1748
1749        kfree(drbg->outscratchpadbuf);
1750        drbg->outscratchpadbuf = NULL;
1751
1752        return 0;
1753}
1754
1755static int drbg_init_sym_kernel(struct drbg_state *drbg)
1756{
1757        struct crypto_cipher *tfm;
1758        struct crypto_skcipher *sk_tfm;
1759        struct skcipher_request *req;
1760        unsigned int alignmask;
1761        char ctr_name[CRYPTO_MAX_ALG_NAME];
1762
1763        tfm = crypto_alloc_cipher(drbg->core->backend_cra_name, 0, 0);
1764        if (IS_ERR(tfm)) {
1765                pr_info("DRBG: could not allocate cipher TFM handle: %s\n",
1766                                drbg->core->backend_cra_name);
1767                return PTR_ERR(tfm);
1768        }
1769        BUG_ON(drbg_blocklen(drbg) != crypto_cipher_blocksize(tfm));
1770        drbg->priv_data = tfm;
1771
1772        if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)",
1773            drbg->core->backend_cra_name) >= CRYPTO_MAX_ALG_NAME) {
1774                drbg_fini_sym_kernel(drbg);
1775                return -EINVAL;
1776        }
1777        sk_tfm = crypto_alloc_skcipher(ctr_name, 0, 0);
1778        if (IS_ERR(sk_tfm)) {
1779                pr_info("DRBG: could not allocate CTR cipher TFM handle: %s\n",
1780                                ctr_name);
1781                drbg_fini_sym_kernel(drbg);
1782                return PTR_ERR(sk_tfm);
1783        }
1784        drbg->ctr_handle = sk_tfm;
1785        crypto_init_wait(&drbg->ctr_wait);
1786
1787        req = skcipher_request_alloc(sk_tfm, GFP_KERNEL);
1788        if (!req) {
1789                pr_info("DRBG: could not allocate request queue\n");
1790                drbg_fini_sym_kernel(drbg);
1791                return -ENOMEM;
1792        }
1793        drbg->ctr_req = req;
1794        skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
1795                                                CRYPTO_TFM_REQ_MAY_SLEEP,
1796                                        crypto_req_done, &drbg->ctr_wait);
1797
1798        alignmask = crypto_skcipher_alignmask(sk_tfm);
1799        drbg->outscratchpadbuf = kmalloc(DRBG_OUTSCRATCHLEN + alignmask,
1800                                         GFP_KERNEL);
1801        if (!drbg->outscratchpadbuf) {
1802                drbg_fini_sym_kernel(drbg);
1803                return -ENOMEM;
1804        }
1805        drbg->outscratchpad = (u8 *)PTR_ALIGN(drbg->outscratchpadbuf,
1806                                              alignmask + 1);
1807
1808        sg_init_table(&drbg->sg_in, 1);
1809        sg_init_one(&drbg->sg_out, drbg->outscratchpad, DRBG_OUTSCRATCHLEN);
1810
1811        return alignmask;
1812}
1813
1814static void drbg_kcapi_symsetkey(struct drbg_state *drbg,
1815                                 const unsigned char *key)
1816{
1817        struct crypto_cipher *tfm =
1818                (struct crypto_cipher *)drbg->priv_data;
1819
1820        crypto_cipher_setkey(tfm, key, (drbg_keylen(drbg)));
1821}
1822
1823static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval,
1824                          const struct drbg_string *in)
1825{
1826        struct crypto_cipher *tfm =
1827                (struct crypto_cipher *)drbg->priv_data;
1828
1829        /* there is only component in *in */
1830        BUG_ON(in->len < drbg_blocklen(drbg));
1831        crypto_cipher_encrypt_one(tfm, outval, in->buf);
1832        return 0;
1833}
1834
1835static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
1836                              u8 *inbuf, u32 inlen,
1837                              u8 *outbuf, u32 outlen)
1838{
1839        struct scatterlist *sg_in = &drbg->sg_in, *sg_out = &drbg->sg_out;
1840        u32 scratchpad_use = min_t(u32, outlen, DRBG_OUTSCRATCHLEN);
1841        int ret;
1842
1843        if (inbuf) {
1844                /* Use caller-provided input buffer */
1845                sg_set_buf(sg_in, inbuf, inlen);
1846        } else {
1847                /* Use scratchpad for in-place operation */
1848                inlen = scratchpad_use;
1849                memset(drbg->outscratchpad, 0, scratchpad_use);
1850                sg_set_buf(sg_in, drbg->outscratchpad, scratchpad_use);
1851        }
1852
1853        while (outlen) {
1854                u32 cryptlen = min3(inlen, outlen, (u32)DRBG_OUTSCRATCHLEN);
1855
1856                /* Output buffer may not be valid for SGL, use scratchpad */
1857                skcipher_request_set_crypt(drbg->ctr_req, sg_in, sg_out,
1858                                           cryptlen, drbg->V);
1859                ret = crypto_wait_req(crypto_skcipher_encrypt(drbg->ctr_req),
1860                                        &drbg->ctr_wait);
1861                if (ret)
1862                        goto out;
1863
1864                crypto_init_wait(&drbg->ctr_wait);
1865
1866                memcpy(outbuf, drbg->outscratchpad, cryptlen);
1867                memzero_explicit(drbg->outscratchpad, cryptlen);
1868
1869                outlen -= cryptlen;
1870                outbuf += cryptlen;
1871        }
1872        ret = 0;
1873
1874out:
1875        return ret;
1876}
1877#endif /* CONFIG_CRYPTO_DRBG_CTR */
1878
1879/***************************************************************
1880 * Kernel crypto API interface to register DRBG
1881 ***************************************************************/
1882
1883/*
1884 * Look up the DRBG flags by given kernel crypto API cra_name
1885 * The code uses the drbg_cores definition to do this
1886 *
1887 * @cra_name kernel crypto API cra_name
1888 * @coreref reference to integer which is filled with the pointer to
1889 *  the applicable core
1890 * @pr reference for setting prediction resistance
1891 *
1892 * return: flags
1893 */
1894static inline void drbg_convert_tfm_core(const char *cra_driver_name,
1895                                         int *coreref, bool *pr)
1896{
1897        int i = 0;
1898        size_t start = 0;
1899        int len = 0;
1900
1901        *pr = true;
1902        /* disassemble the names */
1903        if (!memcmp(cra_driver_name, "drbg_nopr_", 10)) {
1904                start = 10;
1905                *pr = false;
1906        } else if (!memcmp(cra_driver_name, "drbg_pr_", 8)) {
1907                start = 8;
1908        } else {
1909                return;
1910        }
1911
1912        /* remove the first part */
1913        len = strlen(cra_driver_name) - start;
1914        for (i = 0; ARRAY_SIZE(drbg_cores) > i; i++) {
1915                if (!memcmp(cra_driver_name + start, drbg_cores[i].cra_name,
1916                            len)) {
1917                        *coreref = i;
1918                        return;
1919                }
1920        }
1921}
1922
1923static int drbg_kcapi_init(struct crypto_tfm *tfm)
1924{
1925        struct drbg_state *drbg = crypto_tfm_ctx(tfm);
1926
1927        mutex_init(&drbg->drbg_mutex);
1928
1929        return 0;
1930}
1931
1932static void drbg_kcapi_cleanup(struct crypto_tfm *tfm)
1933{
1934        drbg_uninstantiate(crypto_tfm_ctx(tfm));
1935}
1936
1937/*
1938 * Generate random numbers invoked by the kernel crypto API:
1939 * The API of the kernel crypto API is extended as follows:
1940 *
1941 * src is additional input supplied to the RNG.
1942 * slen is the length of src.
1943 * dst is the output buffer where random data is to be stored.
1944 * dlen is the length of dst.
1945 */
1946static int drbg_kcapi_random(struct crypto_rng *tfm,
1947                             const u8 *src, unsigned int slen,
1948                             u8 *dst, unsigned int dlen)
1949{
1950        struct drbg_state *drbg = crypto_rng_ctx(tfm);
1951        struct drbg_string *addtl = NULL;
1952        struct drbg_string string;
1953
1954        if (slen) {
1955                /* linked list variable is now local to allow modification */
1956                drbg_string_fill(&string, src, slen);
1957                addtl = &string;
1958        }
1959
1960        return drbg_generate_long(drbg, dst, dlen, addtl);
1961}
1962
1963/*
1964 * Seed the DRBG invoked by the kernel crypto API
1965 */
1966static int drbg_kcapi_seed(struct crypto_rng *tfm,
1967                           const u8 *seed, unsigned int slen)
1968{
1969        struct drbg_state *drbg = crypto_rng_ctx(tfm);
1970        struct crypto_tfm *tfm_base = crypto_rng_tfm(tfm);
1971        bool pr = false;
1972        struct drbg_string string;
1973        struct drbg_string *seed_string = NULL;
1974        int coreref = 0;
1975
1976        drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base), &coreref,
1977                              &pr);
1978        if (0 < slen) {
1979                drbg_string_fill(&string, seed, slen);
1980                seed_string = &string;
1981        }
1982
1983        return drbg_instantiate(drbg, seed_string, coreref, pr);
1984}
1985
1986/***************************************************************
1987 * Kernel module: code to load the module
1988 ***************************************************************/
1989
1990/*
1991 * Tests as defined in 11.3.2 in addition to the cipher tests: testing
1992 * of the error handling.
1993 *
1994 * Note: testing of failing seed source as defined in 11.3.2 is not applicable
1995 * as seed source of get_random_bytes does not fail.
1996 *
1997 * Note 2: There is no sensible way of testing the reseed counter
1998 * enforcement, so skip it.
1999 */
2000static inline int __init drbg_healthcheck_sanity(void)
2001{
2002        int len = 0;
2003#define OUTBUFLEN 16
2004        unsigned char buf[OUTBUFLEN];
2005        struct drbg_state *drbg = NULL;
2006        int ret = -EFAULT;
2007        int rc = -EFAULT;
2008        bool pr = false;
2009        int coreref = 0;
2010        struct drbg_string addtl;
2011        size_t max_addtllen, max_request_bytes;
2012
2013        /* only perform test in FIPS mode */
2014        if (!fips_enabled)
2015                return 0;
2016
2017#ifdef CONFIG_CRYPTO_DRBG_CTR
2018        drbg_convert_tfm_core("drbg_nopr_ctr_aes128", &coreref, &pr);
2019#elif defined CONFIG_CRYPTO_DRBG_HASH
2020        drbg_convert_tfm_core("drbg_nopr_sha256", &coreref, &pr);
2021#else
2022        drbg_convert_tfm_core("drbg_nopr_hmac_sha256", &coreref, &pr);
2023#endif
2024
2025        drbg = kzalloc(sizeof(struct drbg_state), GFP_KERNEL);
2026        if (!drbg)
2027                return -ENOMEM;
2028
2029        mutex_init(&drbg->drbg_mutex);
2030        drbg->core = &drbg_cores[coreref];
2031        drbg->reseed_threshold = drbg_max_requests(drbg);
2032
2033        /*
2034         * if the following tests fail, it is likely that there is a buffer
2035         * overflow as buf is much smaller than the requested or provided
2036         * string lengths -- in case the error handling does not succeed
2037         * we may get an OOPS. And we want to get an OOPS as this is a
2038         * grave bug.
2039         */
2040
2041        max_addtllen = drbg_max_addtl(drbg);
2042        max_request_bytes = drbg_max_request_bytes(drbg);
2043        drbg_string_fill(&addtl, buf, max_addtllen + 1);
2044        /* overflow addtllen with additonal info string */
2045        len = drbg_generate(drbg, buf, OUTBUFLEN, &addtl);
2046        BUG_ON(0 < len);
2047        /* overflow max_bits */
2048        len = drbg_generate(drbg, buf, (max_request_bytes + 1), NULL);
2049        BUG_ON(0 < len);
2050
2051        /* overflow max addtllen with personalization string */
2052        ret = drbg_seed(drbg, &addtl, false);
2053        BUG_ON(0 == ret);
2054        /* all tests passed */
2055        rc = 0;
2056
2057        pr_devel("DRBG: Sanity tests for failure code paths successfully "
2058                 "completed\n");
2059
2060        kfree(drbg);
2061        return rc;
2062}
2063
2064static struct rng_alg drbg_algs[22];
2065
2066/*
2067 * Fill the array drbg_algs used to register the different DRBGs
2068 * with the kernel crypto API. To fill the array, the information
2069 * from drbg_cores[] is used.
2070 */
2071static inline void __init drbg_fill_array(struct rng_alg *alg,
2072                                          const struct drbg_core *core, int pr)
2073{
2074        int pos = 0;
2075        static int priority = 200;
2076
2077        memcpy(alg->base.cra_name, "stdrng", 6);
2078        if (pr) {
2079                memcpy(alg->base.cra_driver_name, "drbg_pr_", 8);
2080                pos = 8;
2081        } else {
2082                memcpy(alg->base.cra_driver_name, "drbg_nopr_", 10);
2083                pos = 10;
2084        }
2085        memcpy(alg->base.cra_driver_name + pos, core->cra_name,
2086               strlen(core->cra_name));
2087
2088        alg->base.cra_priority = priority;
2089        priority++;
2090        /*
2091         * If FIPS mode enabled, the selected DRBG shall have the
2092         * highest cra_priority over other stdrng instances to ensure
2093         * it is selected.
2094         */
2095        if (fips_enabled)
2096                alg->base.cra_priority += 200;
2097
2098        alg->base.cra_ctxsize   = sizeof(struct drbg_state);
2099        alg->base.cra_module    = THIS_MODULE;
2100        alg->base.cra_init      = drbg_kcapi_init;
2101        alg->base.cra_exit      = drbg_kcapi_cleanup;
2102        alg->generate           = drbg_kcapi_random;
2103        alg->seed               = drbg_kcapi_seed;
2104        alg->set_ent            = drbg_kcapi_set_entropy;
2105        alg->seedsize           = 0;
2106}
2107
2108static int __init drbg_init(void)
2109{
2110        unsigned int i = 0; /* pointer to drbg_algs */
2111        unsigned int j = 0; /* pointer to drbg_cores */
2112        int ret;
2113
2114        ret = drbg_healthcheck_sanity();
2115        if (ret)
2116                return ret;
2117
2118        if (ARRAY_SIZE(drbg_cores) * 2 > ARRAY_SIZE(drbg_algs)) {
2119                pr_info("DRBG: Cannot register all DRBG types"
2120                        "(slots needed: %zu, slots available: %zu)\n",
2121                        ARRAY_SIZE(drbg_cores) * 2, ARRAY_SIZE(drbg_algs));
2122                return -EFAULT;
2123        }
2124
2125        /*
2126         * each DRBG definition can be used with PR and without PR, thus
2127         * we instantiate each DRBG in drbg_cores[] twice.
2128         *
2129         * As the order of placing them into the drbg_algs array matters
2130         * (the later DRBGs receive a higher cra_priority) we register the
2131         * prediction resistance DRBGs first as the should not be too
2132         * interesting.
2133         */
2134        for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
2135                drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 1);
2136        for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
2137                drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 0);
2138        return crypto_register_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
2139}
2140
2141static void __exit drbg_exit(void)
2142{
2143        crypto_unregister_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
2144}
2145
2146subsys_initcall(drbg_init);
2147module_exit(drbg_exit);
2148#ifndef CRYPTO_DRBG_HASH_STRING
2149#define CRYPTO_DRBG_HASH_STRING ""
2150#endif
2151#ifndef CRYPTO_DRBG_HMAC_STRING
2152#define CRYPTO_DRBG_HMAC_STRING ""
2153#endif
2154#ifndef CRYPTO_DRBG_CTR_STRING
2155#define CRYPTO_DRBG_CTR_STRING ""
2156#endif
2157MODULE_LICENSE("GPL");
2158MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
2159MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) "
2160                   "using following cores: "
2161                   CRYPTO_DRBG_HASH_STRING
2162                   CRYPTO_DRBG_HMAC_STRING
2163                   CRYPTO_DRBG_CTR_STRING);
2164MODULE_ALIAS_CRYPTO("stdrng");
2165MODULE_IMPORT_NS(CRYPTO_INTERNAL);
2166
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