1/*
   2 * DRBG: Deterministic Random Bits Generator
   3 *       Based on NIST Recommended DRBG from NIST SP800-90A with the following
   4 *       properties:
   5 *		* CTR DRBG with DF with AES-128, AES-192, AES-256 cores
   6 *		* Hash DRBG with DF with SHA-1, SHA-256, SHA-384, SHA-512 cores
   7 *		* HMAC DRBG with DF with SHA-1, SHA-256, SHA-384, SHA-512 cores
   8 *		* with and without prediction resistance
   9 *
  10 * Copyright Stephan Mueller <smueller@chronox.de>, 2014
  11 *
  12 * Redistribution and use in source and binary forms, with or without
  13 * modification, are permitted provided that the following conditions
  14 * are met:
  15 * 1. Redistributions of source code must retain the above copyright
  16 *    notice, and the entire permission notice in its entirety,
  17 *    including the disclaimer of warranties.
  18 * 2. Redistributions in binary form must reproduce the above copyright
  19 *    notice, this list of conditions and the following disclaimer in the
  20 *    documentation and/or other materials provided with the distribution.
  21 * 3. The name of the author may not be used to endorse or promote
  22 *    products derived from this software without specific prior
  23 *    written permission.
  24 *
  25 * ALTERNATIVELY, this product may be distributed under the terms of
  26 * the GNU General Public License, in which case the provisions of the GPL are
  27 * required INSTEAD OF the above restrictions.  (This clause is
  28 * necessary due to a potential bad interaction between the GPL and
  29 * the restrictions contained in a BSD-style copyright.)
  30 *
  31 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  32 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  33 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
  34 * WHICH ARE HEREBY DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE
  35 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  36 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
  37 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  38 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  39 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  40 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
  41 * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
  42 * DAMAGE.
  43 *
  44 * DRBG Usage
  45 * ==========
  46 * The SP 800-90A DRBG allows the user to specify a personalization string
  47 * for initialization as well as an additional information string for each
  48 * random number request. The following code fragments show how a caller
  49 * uses the kernel crypto API to use the full functionality of the DRBG.
  50 *
  51 * Usage without any additional data
  52 * ---------------------------------
  53 * struct crypto_rng *drng;
  54 * int err;
  55 * char data[DATALEN];
  56 *
  57 * drng = crypto_alloc_rng(drng_name, 0, 0);
  58 * err = crypto_rng_get_bytes(drng, &data, DATALEN);
  59 * crypto_free_rng(drng);
  60 *
  61 *
  62 * Usage with personalization string during initialization
  63 * -------------------------------------------------------
  64 * struct crypto_rng *drng;
  65 * int err;
  66 * char data[DATALEN];
  67 * struct drbg_string pers;
  68 * char personalization[11] = "some-string";
  69 *
  70 * drbg_string_fill(&pers, personalization, strlen(personalization));
  71 * drng = crypto_alloc_rng(drng_name, 0, 0);
  72 * // The reset completely re-initializes the DRBG with the provided
  73 * // personalization string
  74 * err = crypto_rng_reset(drng, &personalization, strlen(personalization));
  75 * err = crypto_rng_get_bytes(drng, &data, DATALEN);
  76 * crypto_free_rng(drng);
  77 *
  78 *
  79 * Usage with additional information string during random number request
  80 * ---------------------------------------------------------------------
  81 * struct crypto_rng *drng;
  82 * int err;
  83 * char data[DATALEN];
  84 * char addtl_string[11] = "some-string";
  85 * string drbg_string addtl;
  86 *
  87 * drbg_string_fill(&addtl, addtl_string, strlen(addtl_string));
  88 * drng = crypto_alloc_rng(drng_name, 0, 0);
  89 * // The following call is a wrapper to crypto_rng_get_bytes() and returns
  90 * // the same error codes.
  91 * err = crypto_drbg_get_bytes_addtl(drng, &data, DATALEN, &addtl);
  92 * crypto_free_rng(drng);
  93 *
  94 *
  95 * Usage with personalization and additional information strings
  96 * -------------------------------------------------------------
  97 * Just mix both scenarios above.
  98 */
  99
 100#include <crypto/drbg.h>
 101#include <crypto/internal/cipher.h>
 102#include <linux/kernel.h>
 103#include <linux/jiffies.h>
 104
 105/***************************************************************
 106 * Backend cipher definitions available to DRBG
 107 ***************************************************************/
 108
 109/*
 110 * The order of the DRBG definitions here matter: every DRBG is registered
 111 * as stdrng. Each DRBG receives an increasing cra_priority values the later
 112 * they are defined in this array (see drbg_fill_array).
 113 *
 114 * HMAC DRBGs are favored over Hash DRBGs over CTR DRBGs, and
 115 * the SHA256 / AES 256 over other ciphers. Thus, the favored
 116 * DRBGs are the latest entries in this array.
 117 */
 118static const struct drbg_core drbg_cores[] = {
 119#ifdef CONFIG_CRYPTO_DRBG_CTR
 120	{
 121		.flags = DRBG_CTR | DRBG_STRENGTH128,
 122		.statelen = 32, /* 256 bits as defined in 10.2.1 */
 123		.blocklen_bytes = 16,
 124		.cra_name = "ctr_aes128",
 125		.backend_cra_name = "aes",
 126	}, {
 127		.flags = DRBG_CTR | DRBG_STRENGTH192,
 128		.statelen = 40, /* 320 bits as defined in 10.2.1 */
 129		.blocklen_bytes = 16,
 130		.cra_name = "ctr_aes192",
 131		.backend_cra_name = "aes",
 132	}, {
 133		.flags = DRBG_CTR | DRBG_STRENGTH256,
 134		.statelen = 48, /* 384 bits as defined in 10.2.1 */
 135		.blocklen_bytes = 16,
 136		.cra_name = "ctr_aes256",
 137		.backend_cra_name = "aes",
 138	},
 139#endif /* CONFIG_CRYPTO_DRBG_CTR */
 140#ifdef CONFIG_CRYPTO_DRBG_HASH
 141	{
 142		.flags = DRBG_HASH | DRBG_STRENGTH128,
 143		.statelen = 55, /* 440 bits */
 144		.blocklen_bytes = 20,
 145		.cra_name = "sha1",
 146		.backend_cra_name = "sha1",
 147	}, {
 148		.flags = DRBG_HASH | DRBG_STRENGTH256,
 149		.statelen = 111, /* 888 bits */
 150		.blocklen_bytes = 48,
 151		.cra_name = "sha384",
 152		.backend_cra_name = "sha384",
 153	}, {
 154		.flags = DRBG_HASH | DRBG_STRENGTH256,
 155		.statelen = 111, /* 888 bits */
 156		.blocklen_bytes = 64,
 157		.cra_name = "sha512",
 158		.backend_cra_name = "sha512",
 159	}, {
 160		.flags = DRBG_HASH | DRBG_STRENGTH256,
 161		.statelen = 55, /* 440 bits */
 162		.blocklen_bytes = 32,
 163		.cra_name = "sha256",
 164		.backend_cra_name = "sha256",
 165	},
 166#endif /* CONFIG_CRYPTO_DRBG_HASH */
 167#ifdef CONFIG_CRYPTO_DRBG_HMAC
 168	{
 169		.flags = DRBG_HMAC | DRBG_STRENGTH128,
 170		.statelen = 20, /* block length of cipher */
 171		.blocklen_bytes = 20,
 172		.cra_name = "hmac_sha1",
 173		.backend_cra_name = "hmac(sha1)",
 174	}, {
 175		.flags = DRBG_HMAC | DRBG_STRENGTH256,
 176		.statelen = 48, /* block length of cipher */
 177		.blocklen_bytes = 48,
 178		.cra_name = "hmac_sha384",
 179		.backend_cra_name = "hmac(sha384)",
 180	}, {
 181		.flags = DRBG_HMAC | DRBG_STRENGTH256,
 182		.statelen = 32, /* block length of cipher */
 183		.blocklen_bytes = 32,
 184		.cra_name = "hmac_sha256",
 185		.backend_cra_name = "hmac(sha256)",
 186	}, {
 187		.flags = DRBG_HMAC | DRBG_STRENGTH256,
 188		.statelen = 64, /* block length of cipher */
 189		.blocklen_bytes = 64,
 190		.cra_name = "hmac_sha512",
 191		.backend_cra_name = "hmac(sha512)",
 
 
 
 
 
 
 192	},
 193#endif /* CONFIG_CRYPTO_DRBG_HMAC */
 194};
 195
 196static int drbg_uninstantiate(struct drbg_state *drbg);
 197
 198/******************************************************************
 199 * Generic helper functions
 200 ******************************************************************/
 201
 202/*
 203 * Return strength of DRBG according to SP800-90A section 8.4
 204 *
 205 * @flags DRBG flags reference
 206 *
 207 * Return: normalized strength in *bytes* value or 32 as default
 208 *	   to counter programming errors
 209 */
 210static inline unsigned short drbg_sec_strength(drbg_flag_t flags)
 211{
 212	switch (flags & DRBG_STRENGTH_MASK) {
 213	case DRBG_STRENGTH128:
 214		return 16;
 215	case DRBG_STRENGTH192:
 216		return 24;
 217	case DRBG_STRENGTH256:
 218		return 32;
 219	default:
 220		return 32;
 221	}
 222}
 223
 224/*
 225 * FIPS 140-2 continuous self test for the noise source
 226 * The test is performed on the noise source input data. Thus, the function
 227 * implicitly knows the size of the buffer to be equal to the security
 228 * strength.
 229 *
 230 * Note, this function disregards the nonce trailing the entropy data during
 231 * initial seeding.
 232 *
 233 * drbg->drbg_mutex must have been taken.
 234 *
 235 * @drbg DRBG handle
 236 * @entropy buffer of seed data to be checked
 237 *
 238 * return:
 239 *	0 on success
 240 *	-EAGAIN on when the CTRNG is not yet primed
 241 *	< 0 on error
 242 */
 243static int drbg_fips_continuous_test(struct drbg_state *drbg,
 244				     const unsigned char *entropy)
 245{
 246	unsigned short entropylen = drbg_sec_strength(drbg->core->flags);
 247	int ret = 0;
 248
 249	if (!IS_ENABLED(CONFIG_CRYPTO_FIPS))
 250		return 0;
 251
 252	/* skip test if we test the overall system */
 253	if (list_empty(&drbg->test_data.list))
 254		return 0;
 255	/* only perform test in FIPS mode */
 256	if (!fips_enabled)
 257		return 0;
 258
 259	if (!drbg->fips_primed) {
 260		/* Priming of FIPS test */
 261		memcpy(drbg->prev, entropy, entropylen);
 262		drbg->fips_primed = true;
 263		/* priming: another round is needed */
 264		return -EAGAIN;
 265	}
 266	ret = memcmp(drbg->prev, entropy, entropylen);
 267	if (!ret)
 268		panic("DRBG continuous self test failed\n");
 269	memcpy(drbg->prev, entropy, entropylen);
 270
 271	/* the test shall pass when the two values are not equal */
 272	return 0;
 273}
 274
 275/*
 276 * Convert an integer into a byte representation of this integer.
 277 * The byte representation is big-endian
 278 *
 279 * @val value to be converted
 280 * @buf buffer holding the converted integer -- caller must ensure that
 281 *      buffer size is at least 32 bit
 282 */
 283#if (defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR))
 284static inline void drbg_cpu_to_be32(__u32 val, unsigned char *buf)
 285{
 286	struct s {
 287		__be32 conv;
 288	};
 289	struct s *conversion = (struct s *) buf;
 290
 291	conversion->conv = cpu_to_be32(val);
 292}
 293#endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */
 294
 295/******************************************************************
 296 * CTR DRBG callback functions
 297 ******************************************************************/
 298
 299#ifdef CONFIG_CRYPTO_DRBG_CTR
 300#define CRYPTO_DRBG_CTR_STRING "CTR "
 301MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes256");
 302MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes256");
 303MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes192");
 304MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes192");
 305MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes128");
 306MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes128");
 307
 308static void drbg_kcapi_symsetkey(struct drbg_state *drbg,
 309				 const unsigned char *key);
 310static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval,
 311			  const struct drbg_string *in);
 312static int drbg_init_sym_kernel(struct drbg_state *drbg);
 313static int drbg_fini_sym_kernel(struct drbg_state *drbg);
 314static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
 315			      u8 *inbuf, u32 inbuflen,
 316			      u8 *outbuf, u32 outlen);
 317#define DRBG_OUTSCRATCHLEN 256
 
 318
 319/* BCC function for CTR DRBG as defined in 10.4.3 */
 320static int drbg_ctr_bcc(struct drbg_state *drbg,
 321			unsigned char *out, const unsigned char *key,
 322			struct list_head *in)
 323{
 324	int ret = 0;
 325	struct drbg_string *curr = NULL;
 326	struct drbg_string data;
 327	short cnt = 0;
 328
 329	drbg_string_fill(&data, out, drbg_blocklen(drbg));
 330
 331	/* 10.4.3 step 2 / 4 */
 332	drbg_kcapi_symsetkey(drbg, key);
 333	list_for_each_entry(curr, in, list) {
 334		const unsigned char *pos = curr->buf;
 335		size_t len = curr->len;
 336		/* 10.4.3 step 4.1 */
 337		while (len) {
 338			/* 10.4.3 step 4.2 */
 339			if (drbg_blocklen(drbg) == cnt) {
 340				cnt = 0;
 341				ret = drbg_kcapi_sym(drbg, out, &data);
 342				if (ret)
 343					return ret;
 344			}
 345			out[cnt] ^= *pos;
 346			pos++;
 347			cnt++;
 348			len--;
 349		}
 350	}
 351	/* 10.4.3 step 4.2 for last block */
 352	if (cnt)
 353		ret = drbg_kcapi_sym(drbg, out, &data);
 354
 355	return ret;
 356}
 357
 358/*
 359 * scratchpad usage: drbg_ctr_update is interlinked with drbg_ctr_df
 360 * (and drbg_ctr_bcc, but this function does not need any temporary buffers),
 361 * the scratchpad is used as follows:
 362 * drbg_ctr_update:
 363 *	temp
 364 *		start: drbg->scratchpad
 365 *		length: drbg_statelen(drbg) + drbg_blocklen(drbg)
 366 *			note: the cipher writing into this variable works
 367 *			blocklen-wise. Now, when the statelen is not a multiple
 368 *			of blocklen, the generateion loop below "spills over"
 369 *			by at most blocklen. Thus, we need to give sufficient
 370 *			memory.
 371 *	df_data
 372 *		start: drbg->scratchpad +
 373 *				drbg_statelen(drbg) + drbg_blocklen(drbg)
 374 *		length: drbg_statelen(drbg)
 375 *
 376 * drbg_ctr_df:
 377 *	pad
 378 *		start: df_data + drbg_statelen(drbg)
 379 *		length: drbg_blocklen(drbg)
 380 *	iv
 381 *		start: pad + drbg_blocklen(drbg)
 382 *		length: drbg_blocklen(drbg)
 383 *	temp
 384 *		start: iv + drbg_blocklen(drbg)
 385 *		length: drbg_satelen(drbg) + drbg_blocklen(drbg)
 386 *			note: temp is the buffer that the BCC function operates
 387 *			on. BCC operates blockwise. drbg_statelen(drbg)
 388 *			is sufficient when the DRBG state length is a multiple
 389 *			of the block size. For AES192 (and maybe other ciphers)
 390 *			this is not correct and the length for temp is
 391 *			insufficient (yes, that also means for such ciphers,
 392 *			the final output of all BCC rounds are truncated).
 393 *			Therefore, add drbg_blocklen(drbg) to cover all
 394 *			possibilities.
 395 */
 396
 397/* Derivation Function for CTR DRBG as defined in 10.4.2 */
 398static int drbg_ctr_df(struct drbg_state *drbg,
 399		       unsigned char *df_data, size_t bytes_to_return,
 400		       struct list_head *seedlist)
 401{
 402	int ret = -EFAULT;
 403	unsigned char L_N[8];
 404	/* S3 is input */
 405	struct drbg_string S1, S2, S4, cipherin;
 406	LIST_HEAD(bcc_list);
 407	unsigned char *pad = df_data + drbg_statelen(drbg);
 408	unsigned char *iv = pad + drbg_blocklen(drbg);
 409	unsigned char *temp = iv + drbg_blocklen(drbg);
 410	size_t padlen = 0;
 411	unsigned int templen = 0;
 412	/* 10.4.2 step 7 */
 413	unsigned int i = 0;
 414	/* 10.4.2 step 8 */
 415	const unsigned char *K = (unsigned char *)
 416			   "\x00\x01\x02\x03\x04\x05\x06\x07"
 417			   "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
 418			   "\x10\x11\x12\x13\x14\x15\x16\x17"
 419			   "\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f";
 420	unsigned char *X;
 421	size_t generated_len = 0;
 422	size_t inputlen = 0;
 423	struct drbg_string *seed = NULL;
 424
 425	memset(pad, 0, drbg_blocklen(drbg));
 426	memset(iv, 0, drbg_blocklen(drbg));
 427
 428	/* 10.4.2 step 1 is implicit as we work byte-wise */
 429
 430	/* 10.4.2 step 2 */
 431	if ((512/8) < bytes_to_return)
 432		return -EINVAL;
 433
 434	/* 10.4.2 step 2 -- calculate the entire length of all input data */
 435	list_for_each_entry(seed, seedlist, list)
 436		inputlen += seed->len;
 437	drbg_cpu_to_be32(inputlen, &L_N[0]);
 438
 439	/* 10.4.2 step 3 */
 440	drbg_cpu_to_be32(bytes_to_return, &L_N[4]);
 441
 442	/* 10.4.2 step 5: length is L_N, input_string, one byte, padding */
 443	padlen = (inputlen + sizeof(L_N) + 1) % (drbg_blocklen(drbg));
 444	/* wrap the padlen appropriately */
 445	if (padlen)
 446		padlen = drbg_blocklen(drbg) - padlen;
 447	/*
 448	 * pad / padlen contains the 0x80 byte and the following zero bytes.
 449	 * As the calculated padlen value only covers the number of zero
 450	 * bytes, this value has to be incremented by one for the 0x80 byte.
 451	 */
 452	padlen++;
 453	pad[0] = 0x80;
 454
 455	/* 10.4.2 step 4 -- first fill the linked list and then order it */
 456	drbg_string_fill(&S1, iv, drbg_blocklen(drbg));
 457	list_add_tail(&S1.list, &bcc_list);
 458	drbg_string_fill(&S2, L_N, sizeof(L_N));
 459	list_add_tail(&S2.list, &bcc_list);
 460	list_splice_tail(seedlist, &bcc_list);
 461	drbg_string_fill(&S4, pad, padlen);
 462	list_add_tail(&S4.list, &bcc_list);
 463
 464	/* 10.4.2 step 9 */
 465	while (templen < (drbg_keylen(drbg) + (drbg_blocklen(drbg)))) {
 466		/*
 467		 * 10.4.2 step 9.1 - the padding is implicit as the buffer
 468		 * holds zeros after allocation -- even the increment of i
 469		 * is irrelevant as the increment remains within length of i
 470		 */
 471		drbg_cpu_to_be32(i, iv);
 472		/* 10.4.2 step 9.2 -- BCC and concatenation with temp */
 473		ret = drbg_ctr_bcc(drbg, temp + templen, K, &bcc_list);
 474		if (ret)
 475			goto out;
 476		/* 10.4.2 step 9.3 */
 477		i++;
 478		templen += drbg_blocklen(drbg);
 479	}
 480
 481	/* 10.4.2 step 11 */
 482	X = temp + (drbg_keylen(drbg));
 483	drbg_string_fill(&cipherin, X, drbg_blocklen(drbg));
 484
 485	/* 10.4.2 step 12: overwriting of outval is implemented in next step */
 486
 487	/* 10.4.2 step 13 */
 488	drbg_kcapi_symsetkey(drbg, temp);
 489	while (generated_len < bytes_to_return) {
 490		short blocklen = 0;
 491		/*
 492		 * 10.4.2 step 13.1: the truncation of the key length is
 493		 * implicit as the key is only drbg_blocklen in size based on
 494		 * the implementation of the cipher function callback
 495		 */
 496		ret = drbg_kcapi_sym(drbg, X, &cipherin);
 497		if (ret)
 498			goto out;
 499		blocklen = (drbg_blocklen(drbg) <
 500				(bytes_to_return - generated_len)) ?
 501			    drbg_blocklen(drbg) :
 502				(bytes_to_return - generated_len);
 503		/* 10.4.2 step 13.2 and 14 */
 504		memcpy(df_data + generated_len, X, blocklen);
 505		generated_len += blocklen;
 506	}
 507
 508	ret = 0;
 509
 510out:
 511	memset(iv, 0, drbg_blocklen(drbg));
 512	memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
 513	memset(pad, 0, drbg_blocklen(drbg));
 514	return ret;
 515}
 516
 517/*
 518 * update function of CTR DRBG as defined in 10.2.1.2
 519 *
 520 * The reseed variable has an enhanced meaning compared to the update
 521 * functions of the other DRBGs as follows:
 522 * 0 => initial seed from initialization
 523 * 1 => reseed via drbg_seed
 524 * 2 => first invocation from drbg_ctr_update when addtl is present. In
 525 *      this case, the df_data scratchpad is not deleted so that it is
 526 *      available for another calls to prevent calling the DF function
 527 *      again.
 528 * 3 => second invocation from drbg_ctr_update. When the update function
 529 *      was called with addtl, the df_data memory already contains the
 530 *      DFed addtl information and we do not need to call DF again.
 531 */
 532static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed,
 533			   int reseed)
 534{
 535	int ret = -EFAULT;
 536	/* 10.2.1.2 step 1 */
 537	unsigned char *temp = drbg->scratchpad;
 538	unsigned char *df_data = drbg->scratchpad + drbg_statelen(drbg) +
 539				 drbg_blocklen(drbg);
 540
 541	if (3 > reseed)
 542		memset(df_data, 0, drbg_statelen(drbg));
 543
 544	if (!reseed) {
 545		/*
 546		 * The DRBG uses the CTR mode of the underlying AES cipher. The
 547		 * CTR mode increments the counter value after the AES operation
 548		 * but SP800-90A requires that the counter is incremented before
 549		 * the AES operation. Hence, we increment it at the time we set
 550		 * it by one.
 551		 */
 552		crypto_inc(drbg->V, drbg_blocklen(drbg));
 553
 554		ret = crypto_skcipher_setkey(drbg->ctr_handle, drbg->C,
 555					     drbg_keylen(drbg));
 556		if (ret)
 557			goto out;
 558	}
 559
 560	/* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */
 561	if (seed) {
 562		ret = drbg_ctr_df(drbg, df_data, drbg_statelen(drbg), seed);
 563		if (ret)
 564			goto out;
 565	}
 566
 567	ret = drbg_kcapi_sym_ctr(drbg, df_data, drbg_statelen(drbg),
 568				 temp, drbg_statelen(drbg));
 569	if (ret)
 570		return ret;
 571
 572	/* 10.2.1.2 step 5 */
 573	ret = crypto_skcipher_setkey(drbg->ctr_handle, temp,
 574				     drbg_keylen(drbg));
 575	if (ret)
 576		goto out;
 577	/* 10.2.1.2 step 6 */
 578	memcpy(drbg->V, temp + drbg_keylen(drbg), drbg_blocklen(drbg));
 579	/* See above: increment counter by one to compensate timing of CTR op */
 580	crypto_inc(drbg->V, drbg_blocklen(drbg));
 581	ret = 0;
 582
 583out:
 584	memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
 585	if (2 != reseed)
 586		memset(df_data, 0, drbg_statelen(drbg));
 587	return ret;
 588}
 589
 590/*
 591 * scratchpad use: drbg_ctr_update is called independently from
 592 * drbg_ctr_extract_bytes. Therefore, the scratchpad is reused
 593 */
 594/* Generate function of CTR DRBG as defined in 10.2.1.5.2 */
 595static int drbg_ctr_generate(struct drbg_state *drbg,
 596			     unsigned char *buf, unsigned int buflen,
 597			     struct list_head *addtl)
 598{
 599	int ret;
 600	int len = min_t(int, buflen, INT_MAX);
 601
 602	/* 10.2.1.5.2 step 2 */
 603	if (addtl && !list_empty(addtl)) {
 604		ret = drbg_ctr_update(drbg, addtl, 2);
 605		if (ret)
 606			return 0;
 607	}
 608
 609	/* 10.2.1.5.2 step 4.1 */
 610	ret = drbg_kcapi_sym_ctr(drbg, NULL, 0, buf, len);
 
 611	if (ret)
 612		return ret;
 613
 614	/* 10.2.1.5.2 step 6 */
 615	ret = drbg_ctr_update(drbg, NULL, 3);
 616	if (ret)
 617		len = ret;
 618
 619	return len;
 620}
 621
 622static const struct drbg_state_ops drbg_ctr_ops = {
 623	.update		= drbg_ctr_update,
 624	.generate	= drbg_ctr_generate,
 625	.crypto_init	= drbg_init_sym_kernel,
 626	.crypto_fini	= drbg_fini_sym_kernel,
 627};
 628#endif /* CONFIG_CRYPTO_DRBG_CTR */
 629
 630/******************************************************************
 631 * HMAC DRBG callback functions
 632 ******************************************************************/
 633
 634#if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
 635static int drbg_kcapi_hash(struct drbg_state *drbg, unsigned char *outval,
 636			   const struct list_head *in);
 637static void drbg_kcapi_hmacsetkey(struct drbg_state *drbg,
 638				  const unsigned char *key);
 639static int drbg_init_hash_kernel(struct drbg_state *drbg);
 640static int drbg_fini_hash_kernel(struct drbg_state *drbg);
 641#endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
 642
 643#ifdef CONFIG_CRYPTO_DRBG_HMAC
 644#define CRYPTO_DRBG_HMAC_STRING "HMAC "
 645MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha512");
 646MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha512");
 647MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha384");
 648MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha384");
 649MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha256");
 650MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha256");
 651MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha1");
 652MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha1");
 653
 654/* update function of HMAC DRBG as defined in 10.1.2.2 */
 655static int drbg_hmac_update(struct drbg_state *drbg, struct list_head *seed,
 656			    int reseed)
 657{
 658	int ret = -EFAULT;
 659	int i = 0;
 660	struct drbg_string seed1, seed2, vdata;
 661	LIST_HEAD(seedlist);
 662	LIST_HEAD(vdatalist);
 663
 664	if (!reseed) {
 665		/* 10.1.2.3 step 2 -- memset(0) of C is implicit with kzalloc */
 666		memset(drbg->V, 1, drbg_statelen(drbg));
 667		drbg_kcapi_hmacsetkey(drbg, drbg->C);
 668	}
 669
 670	drbg_string_fill(&seed1, drbg->V, drbg_statelen(drbg));
 671	list_add_tail(&seed1.list, &seedlist);
 672	/* buffer of seed2 will be filled in for loop below with one byte */
 673	drbg_string_fill(&seed2, NULL, 1);
 674	list_add_tail(&seed2.list, &seedlist);
 675	/* input data of seed is allowed to be NULL at this point */
 676	if (seed)
 677		list_splice_tail(seed, &seedlist);
 678
 679	drbg_string_fill(&vdata, drbg->V, drbg_statelen(drbg));
 680	list_add_tail(&vdata.list, &vdatalist);
 681	for (i = 2; 0 < i; i--) {
 682		/* first round uses 0x0, second 0x1 */
 683		unsigned char prefix = DRBG_PREFIX0;
 684		if (1 == i)
 685			prefix = DRBG_PREFIX1;
 686		/* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */
 687		seed2.buf = &prefix;
 688		ret = drbg_kcapi_hash(drbg, drbg->C, &seedlist);
 689		if (ret)
 690			return ret;
 691		drbg_kcapi_hmacsetkey(drbg, drbg->C);
 692
 693		/* 10.1.2.2 step 2 and 5 -- HMAC for V */
 694		ret = drbg_kcapi_hash(drbg, drbg->V, &vdatalist);
 695		if (ret)
 696			return ret;
 697
 698		/* 10.1.2.2 step 3 */
 699		if (!seed)
 700			return ret;
 701	}
 702
 703	return 0;
 704}
 705
 706/* generate function of HMAC DRBG as defined in 10.1.2.5 */
 707static int drbg_hmac_generate(struct drbg_state *drbg,
 708			      unsigned char *buf,
 709			      unsigned int buflen,
 710			      struct list_head *addtl)
 711{
 712	int len = 0;
 713	int ret = 0;
 714	struct drbg_string data;
 715	LIST_HEAD(datalist);
 716
 717	/* 10.1.2.5 step 2 */
 718	if (addtl && !list_empty(addtl)) {
 719		ret = drbg_hmac_update(drbg, addtl, 1);
 720		if (ret)
 721			return ret;
 722	}
 723
 724	drbg_string_fill(&data, drbg->V, drbg_statelen(drbg));
 725	list_add_tail(&data.list, &datalist);
 726	while (len < buflen) {
 727		unsigned int outlen = 0;
 728		/* 10.1.2.5 step 4.1 */
 729		ret = drbg_kcapi_hash(drbg, drbg->V, &datalist);
 730		if (ret)
 731			return ret;
 732		outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
 733			  drbg_blocklen(drbg) : (buflen - len);
 734
 735		/* 10.1.2.5 step 4.2 */
 736		memcpy(buf + len, drbg->V, outlen);
 737		len += outlen;
 738	}
 739
 740	/* 10.1.2.5 step 6 */
 741	if (addtl && !list_empty(addtl))
 742		ret = drbg_hmac_update(drbg, addtl, 1);
 743	else
 744		ret = drbg_hmac_update(drbg, NULL, 1);
 745	if (ret)
 746		return ret;
 747
 748	return len;
 749}
 750
 751static const struct drbg_state_ops drbg_hmac_ops = {
 752	.update		= drbg_hmac_update,
 753	.generate	= drbg_hmac_generate,
 754	.crypto_init	= drbg_init_hash_kernel,
 755	.crypto_fini	= drbg_fini_hash_kernel,
 756};
 757#endif /* CONFIG_CRYPTO_DRBG_HMAC */
 758
 759/******************************************************************
 760 * Hash DRBG callback functions
 761 ******************************************************************/
 762
 763#ifdef CONFIG_CRYPTO_DRBG_HASH
 764#define CRYPTO_DRBG_HASH_STRING "HASH "
 765MODULE_ALIAS_CRYPTO("drbg_pr_sha512");
 766MODULE_ALIAS_CRYPTO("drbg_nopr_sha512");
 767MODULE_ALIAS_CRYPTO("drbg_pr_sha384");
 768MODULE_ALIAS_CRYPTO("drbg_nopr_sha384");
 769MODULE_ALIAS_CRYPTO("drbg_pr_sha256");
 770MODULE_ALIAS_CRYPTO("drbg_nopr_sha256");
 771MODULE_ALIAS_CRYPTO("drbg_pr_sha1");
 772MODULE_ALIAS_CRYPTO("drbg_nopr_sha1");
 773
 774/*
 775 * Increment buffer
 776 *
 777 * @dst buffer to increment
 778 * @add value to add
 779 */
 780static inline void drbg_add_buf(unsigned char *dst, size_t dstlen,
 781				const unsigned char *add, size_t addlen)
 782{
 783	/* implied: dstlen > addlen */
 784	unsigned char *dstptr;
 785	const unsigned char *addptr;
 786	unsigned int remainder = 0;
 787	size_t len = addlen;
 788
 789	dstptr = dst + (dstlen-1);
 790	addptr = add + (addlen-1);
 791	while (len) {
 792		remainder += *dstptr + *addptr;
 793		*dstptr = remainder & 0xff;
 794		remainder >>= 8;
 795		len--; dstptr--; addptr--;
 796	}
 797	len = dstlen - addlen;
 798	while (len && remainder > 0) {
 799		remainder = *dstptr + 1;
 800		*dstptr = remainder & 0xff;
 801		remainder >>= 8;
 802		len--; dstptr--;
 803	}
 804}
 805
 806/*
 807 * scratchpad usage: as drbg_hash_update and drbg_hash_df are used
 808 * interlinked, the scratchpad is used as follows:
 809 * drbg_hash_update
 810 *	start: drbg->scratchpad
 811 *	length: drbg_statelen(drbg)
 812 * drbg_hash_df:
 813 *	start: drbg->scratchpad + drbg_statelen(drbg)
 814 *	length: drbg_blocklen(drbg)
 815 *
 816 * drbg_hash_process_addtl uses the scratchpad, but fully completes
 817 * before either of the functions mentioned before are invoked. Therefore,
 818 * drbg_hash_process_addtl does not need to be specifically considered.
 819 */
 820
 821/* Derivation Function for Hash DRBG as defined in 10.4.1 */
 822static int drbg_hash_df(struct drbg_state *drbg,
 823			unsigned char *outval, size_t outlen,
 824			struct list_head *entropylist)
 825{
 826	int ret = 0;
 827	size_t len = 0;
 828	unsigned char input[5];
 829	unsigned char *tmp = drbg->scratchpad + drbg_statelen(drbg);
 830	struct drbg_string data;
 831
 832	/* 10.4.1 step 3 */
 833	input[0] = 1;
 834	drbg_cpu_to_be32((outlen * 8), &input[1]);
 835
 836	/* 10.4.1 step 4.1 -- concatenation of data for input into hash */
 837	drbg_string_fill(&data, input, 5);
 838	list_add(&data.list, entropylist);
 839
 840	/* 10.4.1 step 4 */
 841	while (len < outlen) {
 842		short blocklen = 0;
 843		/* 10.4.1 step 4.1 */
 844		ret = drbg_kcapi_hash(drbg, tmp, entropylist);
 845		if (ret)
 846			goto out;
 847		/* 10.4.1 step 4.2 */
 848		input[0]++;
 849		blocklen = (drbg_blocklen(drbg) < (outlen - len)) ?
 850			    drbg_blocklen(drbg) : (outlen - len);
 851		memcpy(outval + len, tmp, blocklen);
 852		len += blocklen;
 853	}
 854
 855out:
 856	memset(tmp, 0, drbg_blocklen(drbg));
 857	return ret;
 858}
 859
 860/* update function for Hash DRBG as defined in 10.1.1.2 / 10.1.1.3 */
 861static int drbg_hash_update(struct drbg_state *drbg, struct list_head *seed,
 862			    int reseed)
 863{
 864	int ret = 0;
 865	struct drbg_string data1, data2;
 866	LIST_HEAD(datalist);
 867	LIST_HEAD(datalist2);
 868	unsigned char *V = drbg->scratchpad;
 869	unsigned char prefix = DRBG_PREFIX1;
 870
 871	if (!seed)
 872		return -EINVAL;
 873
 874	if (reseed) {
 875		/* 10.1.1.3 step 1 */
 876		memcpy(V, drbg->V, drbg_statelen(drbg));
 877		drbg_string_fill(&data1, &prefix, 1);
 878		list_add_tail(&data1.list, &datalist);
 879		drbg_string_fill(&data2, V, drbg_statelen(drbg));
 880		list_add_tail(&data2.list, &datalist);
 881	}
 882	list_splice_tail(seed, &datalist);
 883
 884	/* 10.1.1.2 / 10.1.1.3 step 2 and 3 */
 885	ret = drbg_hash_df(drbg, drbg->V, drbg_statelen(drbg), &datalist);
 886	if (ret)
 887		goto out;
 888
 889	/* 10.1.1.2 / 10.1.1.3 step 4  */
 890	prefix = DRBG_PREFIX0;
 891	drbg_string_fill(&data1, &prefix, 1);
 892	list_add_tail(&data1.list, &datalist2);
 893	drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
 894	list_add_tail(&data2.list, &datalist2);
 895	/* 10.1.1.2 / 10.1.1.3 step 4 */
 896	ret = drbg_hash_df(drbg, drbg->C, drbg_statelen(drbg), &datalist2);
 897
 898out:
 899	memset(drbg->scratchpad, 0, drbg_statelen(drbg));
 900	return ret;
 901}
 902
 903/* processing of additional information string for Hash DRBG */
 904static int drbg_hash_process_addtl(struct drbg_state *drbg,
 905				   struct list_head *addtl)
 906{
 907	int ret = 0;
 908	struct drbg_string data1, data2;
 909	LIST_HEAD(datalist);
 910	unsigned char prefix = DRBG_PREFIX2;
 911
 912	/* 10.1.1.4 step 2 */
 913	if (!addtl || list_empty(addtl))
 914		return 0;
 915
 916	/* 10.1.1.4 step 2a */
 917	drbg_string_fill(&data1, &prefix, 1);
 918	drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
 919	list_add_tail(&data1.list, &datalist);
 920	list_add_tail(&data2.list, &datalist);
 921	list_splice_tail(addtl, &datalist);
 922	ret = drbg_kcapi_hash(drbg, drbg->scratchpad, &datalist);
 923	if (ret)
 924		goto out;
 925
 926	/* 10.1.1.4 step 2b */
 927	drbg_add_buf(drbg->V, drbg_statelen(drbg),
 928		     drbg->scratchpad, drbg_blocklen(drbg));
 929
 930out:
 931	memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
 932	return ret;
 933}
 934
 935/* Hashgen defined in 10.1.1.4 */
 936static int drbg_hash_hashgen(struct drbg_state *drbg,
 937			     unsigned char *buf,
 938			     unsigned int buflen)
 939{
 940	int len = 0;
 941	int ret = 0;
 942	unsigned char *src = drbg->scratchpad;
 943	unsigned char *dst = drbg->scratchpad + drbg_statelen(drbg);
 944	struct drbg_string data;
 945	LIST_HEAD(datalist);
 946
 947	/* 10.1.1.4 step hashgen 2 */
 948	memcpy(src, drbg->V, drbg_statelen(drbg));
 949
 950	drbg_string_fill(&data, src, drbg_statelen(drbg));
 951	list_add_tail(&data.list, &datalist);
 952	while (len < buflen) {
 953		unsigned int outlen = 0;
 954		/* 10.1.1.4 step hashgen 4.1 */
 955		ret = drbg_kcapi_hash(drbg, dst, &datalist);
 956		if (ret) {
 957			len = ret;
 958			goto out;
 959		}
 960		outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
 961			  drbg_blocklen(drbg) : (buflen - len);
 962		/* 10.1.1.4 step hashgen 4.2 */
 963		memcpy(buf + len, dst, outlen);
 964		len += outlen;
 965		/* 10.1.1.4 hashgen step 4.3 */
 966		if (len < buflen)
 967			crypto_inc(src, drbg_statelen(drbg));
 968	}
 969
 970out:
 971	memset(drbg->scratchpad, 0,
 972	       (drbg_statelen(drbg) + drbg_blocklen(drbg)));
 973	return len;
 974}
 975
 976/* generate function for Hash DRBG as defined in  10.1.1.4 */
 977static int drbg_hash_generate(struct drbg_state *drbg,
 978			      unsigned char *buf, unsigned int buflen,
 979			      struct list_head *addtl)
 980{
 981	int len = 0;
 982	int ret = 0;
 983	union {
 984		unsigned char req[8];
 985		__be64 req_int;
 986	} u;
 987	unsigned char prefix = DRBG_PREFIX3;
 988	struct drbg_string data1, data2;
 989	LIST_HEAD(datalist);
 990
 991	/* 10.1.1.4 step 2 */
 992	ret = drbg_hash_process_addtl(drbg, addtl);
 993	if (ret)
 994		return ret;
 995	/* 10.1.1.4 step 3 */
 996	len = drbg_hash_hashgen(drbg, buf, buflen);
 997
 998	/* this is the value H as documented in 10.1.1.4 */
 999	/* 10.1.1.4 step 4 */
1000	drbg_string_fill(&data1, &prefix, 1);
1001	list_add_tail(&data1.list, &datalist);
1002	drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
1003	list_add_tail(&data2.list, &datalist);
1004	ret = drbg_kcapi_hash(drbg, drbg->scratchpad, &datalist);
1005	if (ret) {
1006		len = ret;
1007		goto out;
1008	}
1009
1010	/* 10.1.1.4 step 5 */
1011	drbg_add_buf(drbg->V, drbg_statelen(drbg),
1012		     drbg->scratchpad, drbg_blocklen(drbg));
1013	drbg_add_buf(drbg->V, drbg_statelen(drbg),
1014		     drbg->C, drbg_statelen(drbg));
1015	u.req_int = cpu_to_be64(drbg->reseed_ctr);
1016	drbg_add_buf(drbg->V, drbg_statelen(drbg), u.req, 8);
1017
1018out:
1019	memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
1020	return len;
1021}
1022
1023/*
1024 * scratchpad usage: as update and generate are used isolated, both
1025 * can use the scratchpad
1026 */
1027static const struct drbg_state_ops drbg_hash_ops = {
1028	.update		= drbg_hash_update,
1029	.generate	= drbg_hash_generate,
1030	.crypto_init	= drbg_init_hash_kernel,
1031	.crypto_fini	= drbg_fini_hash_kernel,
1032};
1033#endif /* CONFIG_CRYPTO_DRBG_HASH */
1034
1035/******************************************************************
1036 * Functions common for DRBG implementations
1037 ******************************************************************/
1038
1039static inline int __drbg_seed(struct drbg_state *drbg, struct list_head *seed,
1040			      int reseed, enum drbg_seed_state new_seed_state)
1041{
1042	int ret = drbg->d_ops->update(drbg, seed, reseed);
1043
1044	if (ret)
1045		return ret;
1046
1047	drbg->seeded = new_seed_state;
1048	drbg->last_seed_time = jiffies;
1049	/* 10.1.1.2 / 10.1.1.3 step 5 */
1050	drbg->reseed_ctr = 1;
1051
1052	switch (drbg->seeded) {
1053	case DRBG_SEED_STATE_UNSEEDED:
1054		/* Impossible, but handle it to silence compiler warnings. */
1055		fallthrough;
1056	case DRBG_SEED_STATE_PARTIAL:
1057		/*
1058		 * Require frequent reseeds until the seed source is
1059		 * fully initialized.
1060		 */
1061		drbg->reseed_threshold = 50;
1062		break;
1063
1064	case DRBG_SEED_STATE_FULL:
1065		/*
1066		 * Seed source has become fully initialized, frequent
1067		 * reseeds no longer required.
1068		 */
1069		drbg->reseed_threshold = drbg_max_requests(drbg);
1070		break;
1071	}
1072
1073	return ret;
1074}
1075
1076static inline int drbg_get_random_bytes(struct drbg_state *drbg,
1077					unsigned char *entropy,
1078					unsigned int entropylen)
1079{
1080	int ret;
1081
1082	do {
1083		get_random_bytes(entropy, entropylen);
1084		ret = drbg_fips_continuous_test(drbg, entropy);
1085		if (ret && ret != -EAGAIN)
1086			return ret;
1087	} while (ret);
1088
1089	return 0;
1090}
1091
1092static int drbg_seed_from_random(struct drbg_state *drbg)
1093{
1094	struct drbg_string data;
1095	LIST_HEAD(seedlist);
 
 
1096	unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
1097	unsigned char entropy[32];
1098	int ret;
1099
1100	BUG_ON(!entropylen);
1101	BUG_ON(entropylen > sizeof(entropy));
 
1102
1103	drbg_string_fill(&data, entropy, entropylen);
1104	list_add_tail(&data.list, &seedlist);
1105
1106	ret = drbg_get_random_bytes(drbg, entropy, entropylen);
1107	if (ret)
1108		goto out;
1109
1110	ret = __drbg_seed(drbg, &seedlist, true, DRBG_SEED_STATE_FULL);
 
 
1111
1112out:
1113	memzero_explicit(entropy, entropylen);
1114	return ret;
1115}
1116
1117static bool drbg_nopr_reseed_interval_elapsed(struct drbg_state *drbg)
1118{
1119	unsigned long next_reseed;
1120
1121	/* Don't ever reseed from get_random_bytes() in test mode. */
1122	if (list_empty(&drbg->test_data.list))
1123		return false;
1124
1125	/*
1126	 * Obtain fresh entropy for the nopr DRBGs after 300s have
1127	 * elapsed in order to still achieve sort of partial
1128	 * prediction resistance over the time domain at least. Note
1129	 * that the period of 300s has been chosen to match the
1130	 * CRNG_RESEED_INTERVAL of the get_random_bytes()' chacha
1131	 * rngs.
1132	 */
1133	next_reseed = drbg->last_seed_time + 300 * HZ;
1134	return time_after(jiffies, next_reseed);
1135}
1136
1137/*
1138 * Seeding or reseeding of the DRBG
1139 *
1140 * @drbg: DRBG state struct
1141 * @pers: personalization / additional information buffer
1142 * @reseed: 0 for initial seed process, 1 for reseeding
1143 *
1144 * return:
1145 *	0 on success
1146 *	error value otherwise
1147 */
1148static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
1149		     bool reseed)
1150{
1151	int ret;
1152	unsigned char entropy[((32 + 16) * 2)];
1153	unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
1154	struct drbg_string data1;
1155	LIST_HEAD(seedlist);
1156	enum drbg_seed_state new_seed_state = DRBG_SEED_STATE_FULL;
1157
1158	/* 9.1 / 9.2 / 9.3.1 step 3 */
1159	if (pers && pers->len > (drbg_max_addtl(drbg))) {
1160		pr_devel("DRBG: personalization string too long %zu\n",
1161			 pers->len);
1162		return -EINVAL;
1163	}
1164
1165	if (list_empty(&drbg->test_data.list)) {
1166		drbg_string_fill(&data1, drbg->test_data.buf,
1167				 drbg->test_data.len);
1168		pr_devel("DRBG: using test entropy\n");
1169	} else {
1170		/*
1171		 * Gather entropy equal to the security strength of the DRBG.
1172		 * With a derivation function, a nonce is required in addition
1173		 * to the entropy. A nonce must be at least 1/2 of the security
1174		 * strength of the DRBG in size. Thus, entropy + nonce is 3/2
1175		 * of the strength. The consideration of a nonce is only
1176		 * applicable during initial seeding.
1177		 */
1178		BUG_ON(!entropylen);
1179		if (!reseed)
1180			entropylen = ((entropylen + 1) / 2) * 3;
1181		BUG_ON((entropylen * 2) > sizeof(entropy));
1182
1183		/* Get seed from in-kernel /dev/urandom */
1184		if (!rng_is_initialized())
1185			new_seed_state = DRBG_SEED_STATE_PARTIAL;
1186
1187		ret = drbg_get_random_bytes(drbg, entropy, entropylen);
1188		if (ret)
1189			goto out;
1190
1191		if (!drbg->jent) {
1192			drbg_string_fill(&data1, entropy, entropylen);
1193			pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
1194				 entropylen);
1195		} else {
1196			/*
1197			 * Get seed from Jitter RNG, failures are
1198			 * fatal only in FIPS mode.
1199			 */
1200			ret = crypto_rng_get_bytes(drbg->jent,
1201						   entropy + entropylen,
1202						   entropylen);
1203			if (fips_enabled && ret) {
1204				pr_devel("DRBG: jent failed with %d\n", ret);
1205
1206				/*
1207				 * Do not treat the transient failure of the
1208				 * Jitter RNG as an error that needs to be
1209				 * reported. The combined number of the
1210				 * maximum reseed threshold times the maximum
1211				 * number of Jitter RNG transient errors is
1212				 * less than the reseed threshold required by
1213				 * SP800-90A allowing us to treat the
1214				 * transient errors as such.
1215				 *
1216				 * However, we mandate that at least the first
1217				 * seeding operation must succeed with the
1218				 * Jitter RNG.
1219				 */
1220				if (!reseed || ret != -EAGAIN)
1221					goto out;
1222			}
1223
1224			drbg_string_fill(&data1, entropy, entropylen * 2);
1225			pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
1226				 entropylen * 2);
1227		}
1228	}
1229	list_add_tail(&data1.list, &seedlist);
1230
1231	/*
1232	 * concatenation of entropy with personalization str / addtl input)
1233	 * the variable pers is directly handed in by the caller, so check its
1234	 * contents whether it is appropriate
1235	 */
1236	if (pers && pers->buf && 0 < pers->len) {
1237		list_add_tail(&pers->list, &seedlist);
1238		pr_devel("DRBG: using personalization string\n");
1239	}
1240
1241	if (!reseed) {
1242		memset(drbg->V, 0, drbg_statelen(drbg));
1243		memset(drbg->C, 0, drbg_statelen(drbg));
1244	}
1245
1246	ret = __drbg_seed(drbg, &seedlist, reseed, new_seed_state);
1247
1248out:
1249	memzero_explicit(entropy, entropylen * 2);
1250
1251	return ret;
1252}
1253
1254/* Free all substructures in a DRBG state without the DRBG state structure */
1255static inline void drbg_dealloc_state(struct drbg_state *drbg)
1256{
1257	if (!drbg)
1258		return;
1259	kfree_sensitive(drbg->Vbuf);
1260	drbg->Vbuf = NULL;
1261	drbg->V = NULL;
1262	kfree_sensitive(drbg->Cbuf);
1263	drbg->Cbuf = NULL;
1264	drbg->C = NULL;
1265	kfree_sensitive(drbg->scratchpadbuf);
1266	drbg->scratchpadbuf = NULL;
1267	drbg->reseed_ctr = 0;
1268	drbg->d_ops = NULL;
1269	drbg->core = NULL;
1270	if (IS_ENABLED(CONFIG_CRYPTO_FIPS)) {
1271		kfree_sensitive(drbg->prev);
1272		drbg->prev = NULL;
1273		drbg->fips_primed = false;
1274	}
1275}
1276
1277/*
1278 * Allocate all sub-structures for a DRBG state.
1279 * The DRBG state structure must already be allocated.
1280 */
1281static inline int drbg_alloc_state(struct drbg_state *drbg)
1282{
1283	int ret = -ENOMEM;
1284	unsigned int sb_size = 0;
1285
1286	switch (drbg->core->flags & DRBG_TYPE_MASK) {
1287#ifdef CONFIG_CRYPTO_DRBG_HMAC
1288	case DRBG_HMAC:
1289		drbg->d_ops = &drbg_hmac_ops;
1290		break;
1291#endif /* CONFIG_CRYPTO_DRBG_HMAC */
1292#ifdef CONFIG_CRYPTO_DRBG_HASH
1293	case DRBG_HASH:
1294		drbg->d_ops = &drbg_hash_ops;
1295		break;
1296#endif /* CONFIG_CRYPTO_DRBG_HASH */
1297#ifdef CONFIG_CRYPTO_DRBG_CTR
1298	case DRBG_CTR:
1299		drbg->d_ops = &drbg_ctr_ops;
1300		break;
1301#endif /* CONFIG_CRYPTO_DRBG_CTR */
1302	default:
1303		ret = -EOPNOTSUPP;
1304		goto err;
1305	}
1306
1307	ret = drbg->d_ops->crypto_init(drbg);
1308	if (ret < 0)
1309		goto err;
1310
1311	drbg->Vbuf = kmalloc(drbg_statelen(drbg) + ret, GFP_KERNEL);
1312	if (!drbg->Vbuf) {
1313		ret = -ENOMEM;
1314		goto fini;
1315	}
1316	drbg->V = PTR_ALIGN(drbg->Vbuf, ret + 1);
1317	drbg->Cbuf = kmalloc(drbg_statelen(drbg) + ret, GFP_KERNEL);
1318	if (!drbg->Cbuf) {
1319		ret = -ENOMEM;
1320		goto fini;
1321	}
1322	drbg->C = PTR_ALIGN(drbg->Cbuf, ret + 1);
1323	/* scratchpad is only generated for CTR and Hash */
1324	if (drbg->core->flags & DRBG_HMAC)
1325		sb_size = 0;
1326	else if (drbg->core->flags & DRBG_CTR)
1327		sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg) + /* temp */
1328			  drbg_statelen(drbg) +	/* df_data */
1329			  drbg_blocklen(drbg) +	/* pad */
1330			  drbg_blocklen(drbg) +	/* iv */
1331			  drbg_statelen(drbg) + drbg_blocklen(drbg); /* temp */
1332	else
1333		sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg);
1334
1335	if (0 < sb_size) {
1336		drbg->scratchpadbuf = kzalloc(sb_size + ret, GFP_KERNEL);
1337		if (!drbg->scratchpadbuf) {
1338			ret = -ENOMEM;
1339			goto fini;
1340		}
1341		drbg->scratchpad = PTR_ALIGN(drbg->scratchpadbuf, ret + 1);
1342	}
1343
1344	if (IS_ENABLED(CONFIG_CRYPTO_FIPS)) {
1345		drbg->prev = kzalloc(drbg_sec_strength(drbg->core->flags),
1346				     GFP_KERNEL);
1347		if (!drbg->prev) {
1348			ret = -ENOMEM;
1349			goto fini;
1350		}
1351		drbg->fips_primed = false;
1352	}
1353
1354	return 0;
1355
1356fini:
1357	drbg->d_ops->crypto_fini(drbg);
1358err:
1359	drbg_dealloc_state(drbg);
1360	return ret;
1361}
1362
1363/*************************************************************************
1364 * DRBG interface functions
1365 *************************************************************************/
1366
1367/*
1368 * DRBG generate function as required by SP800-90A - this function
1369 * generates random numbers
1370 *
1371 * @drbg DRBG state handle
1372 * @buf Buffer where to store the random numbers -- the buffer must already
1373 *      be pre-allocated by caller
1374 * @buflen Length of output buffer - this value defines the number of random
1375 *	   bytes pulled from DRBG
1376 * @addtl Additional input that is mixed into state, may be NULL -- note
1377 *	  the entropy is pulled by the DRBG internally unconditionally
1378 *	  as defined in SP800-90A. The additional input is mixed into
1379 *	  the state in addition to the pulled entropy.
1380 *
1381 * return: 0 when all bytes are generated; < 0 in case of an error
1382 */
1383static int drbg_generate(struct drbg_state *drbg,
1384			 unsigned char *buf, unsigned int buflen,
1385			 struct drbg_string *addtl)
1386{
1387	int len = 0;
1388	LIST_HEAD(addtllist);
1389
1390	if (!drbg->core) {
1391		pr_devel("DRBG: not yet seeded\n");
1392		return -EINVAL;
1393	}
1394	if (0 == buflen || !buf) {
1395		pr_devel("DRBG: no output buffer provided\n");
1396		return -EINVAL;
1397	}
1398	if (addtl && NULL == addtl->buf && 0 < addtl->len) {
1399		pr_devel("DRBG: wrong format of additional information\n");
1400		return -EINVAL;
1401	}
1402
1403	/* 9.3.1 step 2 */
1404	len = -EINVAL;
1405	if (buflen > (drbg_max_request_bytes(drbg))) {
1406		pr_devel("DRBG: requested random numbers too large %u\n",
1407			 buflen);
1408		goto err;
1409	}
1410
1411	/* 9.3.1 step 3 is implicit with the chosen DRBG */
1412
1413	/* 9.3.1 step 4 */
1414	if (addtl && addtl->len > (drbg_max_addtl(drbg))) {
1415		pr_devel("DRBG: additional information string too long %zu\n",
1416			 addtl->len);
1417		goto err;
1418	}
1419	/* 9.3.1 step 5 is implicit with the chosen DRBG */
1420
1421	/*
1422	 * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented
1423	 * here. The spec is a bit convoluted here, we make it simpler.
1424	 */
1425	if (drbg->reseed_threshold < drbg->reseed_ctr)
1426		drbg->seeded = DRBG_SEED_STATE_UNSEEDED;
1427
1428	if (drbg->pr || drbg->seeded == DRBG_SEED_STATE_UNSEEDED) {
1429		pr_devel("DRBG: reseeding before generation (prediction "
1430			 "resistance: %s, state %s)\n",
1431			 drbg->pr ? "true" : "false",
1432			 (drbg->seeded ==  DRBG_SEED_STATE_FULL ?
1433			  "seeded" : "unseeded"));
1434		/* 9.3.1 steps 7.1 through 7.3 */
1435		len = drbg_seed(drbg, addtl, true);
1436		if (len)
1437			goto err;
1438		/* 9.3.1 step 7.4 */
1439		addtl = NULL;
1440	} else if (rng_is_initialized() &&
1441		   (drbg->seeded == DRBG_SEED_STATE_PARTIAL ||
1442		    drbg_nopr_reseed_interval_elapsed(drbg))) {
1443		len = drbg_seed_from_random(drbg);
1444		if (len)
1445			goto err;
1446	}
1447
1448	if (addtl && 0 < addtl->len)
1449		list_add_tail(&addtl->list, &addtllist);
1450	/* 9.3.1 step 8 and 10 */
1451	len = drbg->d_ops->generate(drbg, buf, buflen, &addtllist);
1452
1453	/* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */
1454	drbg->reseed_ctr++;
1455	if (0 >= len)
1456		goto err;
1457
1458	/*
1459	 * Section 11.3.3 requires to re-perform self tests after some
1460	 * generated random numbers. The chosen value after which self
1461	 * test is performed is arbitrary, but it should be reasonable.
1462	 * However, we do not perform the self tests because of the following
1463	 * reasons: it is mathematically impossible that the initial self tests
1464	 * were successfully and the following are not. If the initial would
1465	 * pass and the following would not, the kernel integrity is violated.
1466	 * In this case, the entire kernel operation is questionable and it
1467	 * is unlikely that the integrity violation only affects the
1468	 * correct operation of the DRBG.
1469	 *
1470	 * Albeit the following code is commented out, it is provided in
1471	 * case somebody has a need to implement the test of 11.3.3.
1472	 */
1473#if 0
1474	if (drbg->reseed_ctr && !(drbg->reseed_ctr % 4096)) {
1475		int err = 0;
1476		pr_devel("DRBG: start to perform self test\n");
1477		if (drbg->core->flags & DRBG_HMAC)
1478			err = alg_test("drbg_pr_hmac_sha256",
1479				       "drbg_pr_hmac_sha256", 0, 0);
1480		else if (drbg->core->flags & DRBG_CTR)
1481			err = alg_test("drbg_pr_ctr_aes128",
1482				       "drbg_pr_ctr_aes128", 0, 0);
1483		else
1484			err = alg_test("drbg_pr_sha256",
1485				       "drbg_pr_sha256", 0, 0);
1486		if (err) {
1487			pr_err("DRBG: periodical self test failed\n");
1488			/*
1489			 * uninstantiate implies that from now on, only errors
1490			 * are returned when reusing this DRBG cipher handle
1491			 */
1492			drbg_uninstantiate(drbg);
1493			return 0;
1494		} else {
1495			pr_devel("DRBG: self test successful\n");
1496		}
1497	}
1498#endif
1499
1500	/*
1501	 * All operations were successful, return 0 as mandated by
1502	 * the kernel crypto API interface.
1503	 */
1504	len = 0;
1505err:
1506	return len;
1507}
1508
1509/*
1510 * Wrapper around drbg_generate which can pull arbitrary long strings
1511 * from the DRBG without hitting the maximum request limitation.
1512 *
1513 * Parameters: see drbg_generate
1514 * Return codes: see drbg_generate -- if one drbg_generate request fails,
1515 *		 the entire drbg_generate_long request fails
1516 */
1517static int drbg_generate_long(struct drbg_state *drbg,
1518			      unsigned char *buf, unsigned int buflen,
1519			      struct drbg_string *addtl)
1520{
1521	unsigned int len = 0;
1522	unsigned int slice = 0;
1523	do {
1524		int err = 0;
1525		unsigned int chunk = 0;
1526		slice = ((buflen - len) / drbg_max_request_bytes(drbg));
1527		chunk = slice ? drbg_max_request_bytes(drbg) : (buflen - len);
1528		mutex_lock(&drbg->drbg_mutex);
1529		err = drbg_generate(drbg, buf + len, chunk, addtl);
1530		mutex_unlock(&drbg->drbg_mutex);
1531		if (0 > err)
1532			return err;
1533		len += chunk;
1534	} while (slice > 0 && (len < buflen));
1535	return 0;
1536}
1537
 
 
 
 
 
 
 
 
1538static int drbg_prepare_hrng(struct drbg_state *drbg)
1539{
 
 
1540	/* We do not need an HRNG in test mode. */
1541	if (list_empty(&drbg->test_data.list))
1542		return 0;
1543
1544	drbg->jent = crypto_alloc_rng("jitterentropy_rng", 0, 0);
1545	if (IS_ERR(drbg->jent)) {
1546		const int err = PTR_ERR(drbg->jent);
1547
1548		drbg->jent = NULL;
1549		if (fips_enabled || err != -ENOENT)
1550			return err;
1551		pr_info("DRBG: Continuing without Jitter RNG\n");
 
 
 
 
 
 
 
 
 
 
 
 
1552	}
1553
1554	return 0;
 
 
 
 
 
 
 
 
1555}
1556
1557/*
1558 * DRBG instantiation function as required by SP800-90A - this function
1559 * sets up the DRBG handle, performs the initial seeding and all sanity
1560 * checks required by SP800-90A
1561 *
1562 * @drbg memory of state -- if NULL, new memory is allocated
1563 * @pers Personalization string that is mixed into state, may be NULL -- note
1564 *	 the entropy is pulled by the DRBG internally unconditionally
1565 *	 as defined in SP800-90A. The additional input is mixed into
1566 *	 the state in addition to the pulled entropy.
1567 * @coreref reference to core
1568 * @pr prediction resistance enabled
1569 *
1570 * return
1571 *	0 on success
1572 *	error value otherwise
1573 */
1574static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers,
1575			    int coreref, bool pr)
1576{
1577	int ret;
1578	bool reseed = true;
1579
1580	pr_devel("DRBG: Initializing DRBG core %d with prediction resistance "
1581		 "%s\n", coreref, pr ? "enabled" : "disabled");
1582	mutex_lock(&drbg->drbg_mutex);
1583
1584	/* 9.1 step 1 is implicit with the selected DRBG type */
1585
1586	/*
1587	 * 9.1 step 2 is implicit as caller can select prediction resistance
1588	 * and the flag is copied into drbg->flags --
1589	 * all DRBG types support prediction resistance
1590	 */
1591
1592	/* 9.1 step 4 is implicit in  drbg_sec_strength */
1593
1594	if (!drbg->core) {
1595		drbg->core = &drbg_cores[coreref];
1596		drbg->pr = pr;
1597		drbg->seeded = DRBG_SEED_STATE_UNSEEDED;
1598		drbg->last_seed_time = 0;
1599		drbg->reseed_threshold = drbg_max_requests(drbg);
1600
1601		ret = drbg_alloc_state(drbg);
1602		if (ret)
1603			goto unlock;
1604
1605		ret = drbg_prepare_hrng(drbg);
1606		if (ret)
1607			goto free_everything;
1608
 
 
 
 
 
 
 
 
1609		reseed = false;
1610	}
1611
1612	ret = drbg_seed(drbg, pers, reseed);
1613
1614	if (ret && !reseed)
1615		goto free_everything;
1616
1617	mutex_unlock(&drbg->drbg_mutex);
1618	return ret;
1619
1620unlock:
1621	mutex_unlock(&drbg->drbg_mutex);
1622	return ret;
1623
1624free_everything:
1625	mutex_unlock(&drbg->drbg_mutex);
1626	drbg_uninstantiate(drbg);
1627	return ret;
1628}
1629
1630/*
1631 * DRBG uninstantiate function as required by SP800-90A - this function
1632 * frees all buffers and the DRBG handle
1633 *
1634 * @drbg DRBG state handle
1635 *
1636 * return
1637 *	0 on success
1638 */
1639static int drbg_uninstantiate(struct drbg_state *drbg)
1640{
1641	if (!IS_ERR_OR_NULL(drbg->jent))
 
 
1642		crypto_free_rng(drbg->jent);
1643	drbg->jent = NULL;
 
1644
1645	if (drbg->d_ops)
1646		drbg->d_ops->crypto_fini(drbg);
1647	drbg_dealloc_state(drbg);
1648	/* no scrubbing of test_data -- this shall survive an uninstantiate */
1649	return 0;
1650}
1651
1652/*
1653 * Helper function for setting the test data in the DRBG
1654 *
1655 * @drbg DRBG state handle
1656 * @data test data
1657 * @len test data length
1658 */
1659static void drbg_kcapi_set_entropy(struct crypto_rng *tfm,
1660				   const u8 *data, unsigned int len)
1661{
1662	struct drbg_state *drbg = crypto_rng_ctx(tfm);
1663
1664	mutex_lock(&drbg->drbg_mutex);
1665	drbg_string_fill(&drbg->test_data, data, len);
1666	mutex_unlock(&drbg->drbg_mutex);
1667}
1668
1669/***************************************************************
1670 * Kernel crypto API cipher invocations requested by DRBG
1671 ***************************************************************/
1672
1673#if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
1674struct sdesc {
1675	struct shash_desc shash;
1676	char ctx[];
1677};
1678
1679static int drbg_init_hash_kernel(struct drbg_state *drbg)
1680{
1681	struct sdesc *sdesc;
1682	struct crypto_shash *tfm;
1683
1684	tfm = crypto_alloc_shash(drbg->core->backend_cra_name, 0, 0);
1685	if (IS_ERR(tfm)) {
1686		pr_info("DRBG: could not allocate digest TFM handle: %s\n",
1687				drbg->core->backend_cra_name);
1688		return PTR_ERR(tfm);
1689	}
1690	BUG_ON(drbg_blocklen(drbg) != crypto_shash_digestsize(tfm));
1691	sdesc = kzalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm),
1692			GFP_KERNEL);
1693	if (!sdesc) {
1694		crypto_free_shash(tfm);
1695		return -ENOMEM;
1696	}
1697
1698	sdesc->shash.tfm = tfm;
 
1699	drbg->priv_data = sdesc;
1700
1701	return crypto_shash_alignmask(tfm);
1702}
1703
1704static int drbg_fini_hash_kernel(struct drbg_state *drbg)
1705{
1706	struct sdesc *sdesc = drbg->priv_data;
1707	if (sdesc) {
1708		crypto_free_shash(sdesc->shash.tfm);
1709		kfree_sensitive(sdesc);
1710	}
1711	drbg->priv_data = NULL;
1712	return 0;
1713}
1714
1715static void drbg_kcapi_hmacsetkey(struct drbg_state *drbg,
1716				  const unsigned char *key)
1717{
1718	struct sdesc *sdesc = drbg->priv_data;
1719
1720	crypto_shash_setkey(sdesc->shash.tfm, key, drbg_statelen(drbg));
1721}
1722
1723static int drbg_kcapi_hash(struct drbg_state *drbg, unsigned char *outval,
1724			   const struct list_head *in)
1725{
1726	struct sdesc *sdesc = drbg->priv_data;
1727	struct drbg_string *input = NULL;
1728
1729	crypto_shash_init(&sdesc->shash);
1730	list_for_each_entry(input, in, list)
1731		crypto_shash_update(&sdesc->shash, input->buf, input->len);
1732	return crypto_shash_final(&sdesc->shash, outval);
1733}
1734#endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
1735
1736#ifdef CONFIG_CRYPTO_DRBG_CTR
1737static int drbg_fini_sym_kernel(struct drbg_state *drbg)
1738{
1739	struct crypto_cipher *tfm =
1740		(struct crypto_cipher *)drbg->priv_data;
1741	if (tfm)
1742		crypto_free_cipher(tfm);
1743	drbg->priv_data = NULL;
1744
1745	if (drbg->ctr_handle)
1746		crypto_free_skcipher(drbg->ctr_handle);
1747	drbg->ctr_handle = NULL;
1748
1749	if (drbg->ctr_req)
1750		skcipher_request_free(drbg->ctr_req);
1751	drbg->ctr_req = NULL;
1752
 
 
 
1753	kfree(drbg->outscratchpadbuf);
1754	drbg->outscratchpadbuf = NULL;
1755
1756	return 0;
1757}
1758
 
 
 
 
 
 
 
 
 
 
1759static int drbg_init_sym_kernel(struct drbg_state *drbg)
1760{
1761	struct crypto_cipher *tfm;
1762	struct crypto_skcipher *sk_tfm;
1763	struct skcipher_request *req;
1764	unsigned int alignmask;
1765	char ctr_name[CRYPTO_MAX_ALG_NAME];
1766
1767	tfm = crypto_alloc_cipher(drbg->core->backend_cra_name, 0, 0);
1768	if (IS_ERR(tfm)) {
1769		pr_info("DRBG: could not allocate cipher TFM handle: %s\n",
1770				drbg->core->backend_cra_name);
1771		return PTR_ERR(tfm);
1772	}
1773	BUG_ON(drbg_blocklen(drbg) != crypto_cipher_blocksize(tfm));
1774	drbg->priv_data = tfm;
1775
1776	if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)",
1777	    drbg->core->backend_cra_name) >= CRYPTO_MAX_ALG_NAME) {
1778		drbg_fini_sym_kernel(drbg);
1779		return -EINVAL;
1780	}
1781	sk_tfm = crypto_alloc_skcipher(ctr_name, 0, 0);
1782	if (IS_ERR(sk_tfm)) {
1783		pr_info("DRBG: could not allocate CTR cipher TFM handle: %s\n",
1784				ctr_name);
1785		drbg_fini_sym_kernel(drbg);
1786		return PTR_ERR(sk_tfm);
1787	}
1788	drbg->ctr_handle = sk_tfm;
1789	crypto_init_wait(&drbg->ctr_wait);
1790
1791	req = skcipher_request_alloc(sk_tfm, GFP_KERNEL);
1792	if (!req) {
1793		pr_info("DRBG: could not allocate request queue\n");
1794		drbg_fini_sym_kernel(drbg);
1795		return -ENOMEM;
1796	}
1797	drbg->ctr_req = req;
1798	skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
1799						CRYPTO_TFM_REQ_MAY_SLEEP,
1800					crypto_req_done, &drbg->ctr_wait);
1801
1802	alignmask = crypto_skcipher_alignmask(sk_tfm);
 
 
 
 
 
 
 
 
 
1803	drbg->outscratchpadbuf = kmalloc(DRBG_OUTSCRATCHLEN + alignmask,
1804					 GFP_KERNEL);
1805	if (!drbg->outscratchpadbuf) {
1806		drbg_fini_sym_kernel(drbg);
1807		return -ENOMEM;
1808	}
1809	drbg->outscratchpad = (u8 *)PTR_ALIGN(drbg->outscratchpadbuf,
1810					      alignmask + 1);
1811
1812	sg_init_table(&drbg->sg_in, 1);
1813	sg_init_one(&drbg->sg_out, drbg->outscratchpad, DRBG_OUTSCRATCHLEN);
1814
1815	return alignmask;
1816}
1817
1818static void drbg_kcapi_symsetkey(struct drbg_state *drbg,
1819				 const unsigned char *key)
1820{
1821	struct crypto_cipher *tfm = drbg->priv_data;
 
1822
1823	crypto_cipher_setkey(tfm, key, (drbg_keylen(drbg)));
1824}
1825
1826static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval,
1827			  const struct drbg_string *in)
1828{
1829	struct crypto_cipher *tfm = drbg->priv_data;
 
1830
1831	/* there is only component in *in */
1832	BUG_ON(in->len < drbg_blocklen(drbg));
1833	crypto_cipher_encrypt_one(tfm, outval, in->buf);
1834	return 0;
1835}
1836
1837static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
1838			      u8 *inbuf, u32 inlen,
1839			      u8 *outbuf, u32 outlen)
1840{
1841	struct scatterlist *sg_in = &drbg->sg_in, *sg_out = &drbg->sg_out;
1842	u32 scratchpad_use = min_t(u32, outlen, DRBG_OUTSCRATCHLEN);
1843	int ret;
1844
1845	if (inbuf) {
1846		/* Use caller-provided input buffer */
1847		sg_set_buf(sg_in, inbuf, inlen);
1848	} else {
1849		/* Use scratchpad for in-place operation */
1850		inlen = scratchpad_use;
1851		memset(drbg->outscratchpad, 0, scratchpad_use);
1852		sg_set_buf(sg_in, drbg->outscratchpad, scratchpad_use);
1853	}
1854
1855	while (outlen) {
1856		u32 cryptlen = min3(inlen, outlen, (u32)DRBG_OUTSCRATCHLEN);
 
1857
1858		/* Output buffer may not be valid for SGL, use scratchpad */
1859		skcipher_request_set_crypt(drbg->ctr_req, sg_in, sg_out,
 
1860					   cryptlen, drbg->V);
1861		ret = crypto_wait_req(crypto_skcipher_encrypt(drbg->ctr_req),
1862					&drbg->ctr_wait);
1863		if (ret)
 
 
 
 
 
 
 
 
 
 
1864			goto out;
1865
1866		crypto_init_wait(&drbg->ctr_wait);
1867
1868		memcpy(outbuf, drbg->outscratchpad, cryptlen);
1869		memzero_explicit(drbg->outscratchpad, cryptlen);
1870
1871		outlen -= cryptlen;
1872		outbuf += cryptlen;
1873	}
1874	ret = 0;
1875
1876out:
 
1877	return ret;
1878}
1879#endif /* CONFIG_CRYPTO_DRBG_CTR */
1880
1881/***************************************************************
1882 * Kernel crypto API interface to register DRBG
1883 ***************************************************************/
1884
1885/*
1886 * Look up the DRBG flags by given kernel crypto API cra_name
1887 * The code uses the drbg_cores definition to do this
1888 *
1889 * @cra_name kernel crypto API cra_name
1890 * @coreref reference to integer which is filled with the pointer to
1891 *  the applicable core
1892 * @pr reference for setting prediction resistance
1893 *
1894 * return: flags
1895 */
1896static inline void drbg_convert_tfm_core(const char *cra_driver_name,
1897					 int *coreref, bool *pr)
1898{
1899	int i = 0;
1900	size_t start = 0;
1901	int len = 0;
1902
1903	*pr = true;
1904	/* disassemble the names */
1905	if (!memcmp(cra_driver_name, "drbg_nopr_", 10)) {
1906		start = 10;
1907		*pr = false;
1908	} else if (!memcmp(cra_driver_name, "drbg_pr_", 8)) {
1909		start = 8;
1910	} else {
1911		return;
1912	}
1913
1914	/* remove the first part */
1915	len = strlen(cra_driver_name) - start;
1916	for (i = 0; ARRAY_SIZE(drbg_cores) > i; i++) {
1917		if (!memcmp(cra_driver_name + start, drbg_cores[i].cra_name,
1918			    len)) {
1919			*coreref = i;
1920			return;
1921		}
1922	}
1923}
1924
1925static int drbg_kcapi_init(struct crypto_tfm *tfm)
1926{
1927	struct drbg_state *drbg = crypto_tfm_ctx(tfm);
1928
1929	mutex_init(&drbg->drbg_mutex);
1930
1931	return 0;
1932}
1933
1934static void drbg_kcapi_cleanup(struct crypto_tfm *tfm)
1935{
1936	drbg_uninstantiate(crypto_tfm_ctx(tfm));
1937}
1938
1939/*
1940 * Generate random numbers invoked by the kernel crypto API:
1941 * The API of the kernel crypto API is extended as follows:
1942 *
1943 * src is additional input supplied to the RNG.
1944 * slen is the length of src.
1945 * dst is the output buffer where random data is to be stored.
1946 * dlen is the length of dst.
1947 */
1948static int drbg_kcapi_random(struct crypto_rng *tfm,
1949			     const u8 *src, unsigned int slen,
1950			     u8 *dst, unsigned int dlen)
1951{
1952	struct drbg_state *drbg = crypto_rng_ctx(tfm);
1953	struct drbg_string *addtl = NULL;
1954	struct drbg_string string;
1955
1956	if (slen) {
1957		/* linked list variable is now local to allow modification */
1958		drbg_string_fill(&string, src, slen);
1959		addtl = &string;
1960	}
1961
1962	return drbg_generate_long(drbg, dst, dlen, addtl);
1963}
1964
1965/*
1966 * Seed the DRBG invoked by the kernel crypto API
1967 */
1968static int drbg_kcapi_seed(struct crypto_rng *tfm,
1969			   const u8 *seed, unsigned int slen)
1970{
1971	struct drbg_state *drbg = crypto_rng_ctx(tfm);
1972	struct crypto_tfm *tfm_base = crypto_rng_tfm(tfm);
1973	bool pr = false;
1974	struct drbg_string string;
1975	struct drbg_string *seed_string = NULL;
1976	int coreref = 0;
1977
1978	drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base), &coreref,
1979			      &pr);
1980	if (0 < slen) {
1981		drbg_string_fill(&string, seed, slen);
1982		seed_string = &string;
1983	}
1984
1985	return drbg_instantiate(drbg, seed_string, coreref, pr);
1986}
1987
1988/***************************************************************
1989 * Kernel module: code to load the module
1990 ***************************************************************/
1991
1992/*
1993 * Tests as defined in 11.3.2 in addition to the cipher tests: testing
1994 * of the error handling.
1995 *
1996 * Note: testing of failing seed source as defined in 11.3.2 is not applicable
1997 * as seed source of get_random_bytes does not fail.
1998 *
1999 * Note 2: There is no sensible way of testing the reseed counter
2000 * enforcement, so skip it.
2001 */
2002static inline int __init drbg_healthcheck_sanity(void)
2003{
2004	int len = 0;
2005#define OUTBUFLEN 16
2006	unsigned char buf[OUTBUFLEN];
2007	struct drbg_state *drbg = NULL;
2008	int ret;
2009	int rc = -EFAULT;
2010	bool pr = false;
2011	int coreref = 0;
2012	struct drbg_string addtl;
2013	size_t max_addtllen, max_request_bytes;
2014
2015	/* only perform test in FIPS mode */
2016	if (!fips_enabled)
2017		return 0;
2018
2019#ifdef CONFIG_CRYPTO_DRBG_CTR
2020	drbg_convert_tfm_core("drbg_nopr_ctr_aes128", &coreref, &pr);
2021#elif defined CONFIG_CRYPTO_DRBG_HASH
2022	drbg_convert_tfm_core("drbg_nopr_sha256", &coreref, &pr);
2023#else
2024	drbg_convert_tfm_core("drbg_nopr_hmac_sha256", &coreref, &pr);
2025#endif
2026
2027	drbg = kzalloc(sizeof(struct drbg_state), GFP_KERNEL);
2028	if (!drbg)
2029		return -ENOMEM;
2030
2031	mutex_init(&drbg->drbg_mutex);
2032	drbg->core = &drbg_cores[coreref];
2033	drbg->reseed_threshold = drbg_max_requests(drbg);
2034
2035	/*
2036	 * if the following tests fail, it is likely that there is a buffer
2037	 * overflow as buf is much smaller than the requested or provided
2038	 * string lengths -- in case the error handling does not succeed
2039	 * we may get an OOPS. And we want to get an OOPS as this is a
2040	 * grave bug.
2041	 */
2042
2043	max_addtllen = drbg_max_addtl(drbg);
2044	max_request_bytes = drbg_max_request_bytes(drbg);
2045	drbg_string_fill(&addtl, buf, max_addtllen + 1);
2046	/* overflow addtllen with additonal info string */
2047	len = drbg_generate(drbg, buf, OUTBUFLEN, &addtl);
2048	BUG_ON(0 < len);
2049	/* overflow max_bits */
2050	len = drbg_generate(drbg, buf, (max_request_bytes + 1), NULL);
2051	BUG_ON(0 < len);
2052
2053	/* overflow max addtllen with personalization string */
2054	ret = drbg_seed(drbg, &addtl, false);
2055	BUG_ON(0 == ret);
2056	/* all tests passed */
2057	rc = 0;
2058
2059	pr_devel("DRBG: Sanity tests for failure code paths successfully "
2060		 "completed\n");
2061
2062	kfree(drbg);
2063	return rc;
2064}
2065
2066static struct rng_alg drbg_algs[22];
2067
2068/*
2069 * Fill the array drbg_algs used to register the different DRBGs
2070 * with the kernel crypto API. To fill the array, the information
2071 * from drbg_cores[] is used.
2072 */
2073static inline void __init drbg_fill_array(struct rng_alg *alg,
2074					  const struct drbg_core *core, int pr)
2075{
2076	int pos = 0;
2077	static int priority = 200;
2078
2079	memcpy(alg->base.cra_name, "stdrng", 6);
2080	if (pr) {
2081		memcpy(alg->base.cra_driver_name, "drbg_pr_", 8);
2082		pos = 8;
2083	} else {
2084		memcpy(alg->base.cra_driver_name, "drbg_nopr_", 10);
2085		pos = 10;
2086	}
2087	memcpy(alg->base.cra_driver_name + pos, core->cra_name,
2088	       strlen(core->cra_name));
2089
2090	alg->base.cra_priority = priority;
2091	priority++;
2092	/*
2093	 * If FIPS mode enabled, the selected DRBG shall have the
2094	 * highest cra_priority over other stdrng instances to ensure
2095	 * it is selected.
2096	 */
2097	if (fips_enabled)
2098		alg->base.cra_priority += 200;
2099
2100	alg->base.cra_ctxsize 	= sizeof(struct drbg_state);
2101	alg->base.cra_module	= THIS_MODULE;
2102	alg->base.cra_init	= drbg_kcapi_init;
2103	alg->base.cra_exit	= drbg_kcapi_cleanup;
2104	alg->generate		= drbg_kcapi_random;
2105	alg->seed		= drbg_kcapi_seed;
2106	alg->set_ent		= drbg_kcapi_set_entropy;
2107	alg->seedsize		= 0;
2108}
2109
2110static int __init drbg_init(void)
2111{
2112	unsigned int i = 0; /* pointer to drbg_algs */
2113	unsigned int j = 0; /* pointer to drbg_cores */
2114	int ret;
2115
2116	ret = drbg_healthcheck_sanity();
2117	if (ret)
2118		return ret;
2119
2120	if (ARRAY_SIZE(drbg_cores) * 2 > ARRAY_SIZE(drbg_algs)) {
2121		pr_info("DRBG: Cannot register all DRBG types"
2122			"(slots needed: %zu, slots available: %zu)\n",
2123			ARRAY_SIZE(drbg_cores) * 2, ARRAY_SIZE(drbg_algs));
2124		return -EFAULT;
2125	}
2126
2127	/*
2128	 * each DRBG definition can be used with PR and without PR, thus
2129	 * we instantiate each DRBG in drbg_cores[] twice.
2130	 *
2131	 * As the order of placing them into the drbg_algs array matters
2132	 * (the later DRBGs receive a higher cra_priority) we register the
2133	 * prediction resistance DRBGs first as the should not be too
2134	 * interesting.
2135	 */
2136	for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
2137		drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 1);
2138	for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
2139		drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 0);
2140	return crypto_register_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
2141}
2142
2143static void __exit drbg_exit(void)
2144{
2145	crypto_unregister_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
2146}
2147
2148subsys_initcall(drbg_init);
2149module_exit(drbg_exit);
2150#ifndef CRYPTO_DRBG_HASH_STRING
2151#define CRYPTO_DRBG_HASH_STRING ""
2152#endif
2153#ifndef CRYPTO_DRBG_HMAC_STRING
2154#define CRYPTO_DRBG_HMAC_STRING ""
2155#endif
2156#ifndef CRYPTO_DRBG_CTR_STRING
2157#define CRYPTO_DRBG_CTR_STRING ""
2158#endif
2159MODULE_LICENSE("GPL");
2160MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
2161MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) "
2162		   "using following cores: "
2163		   CRYPTO_DRBG_HASH_STRING
2164		   CRYPTO_DRBG_HMAC_STRING
2165		   CRYPTO_DRBG_CTR_STRING);
2166MODULE_ALIAS_CRYPTO("stdrng");
2167MODULE_IMPORT_NS(CRYPTO_INTERNAL);