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