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