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	/* Set seeded to false so that if __drbg_seed fails the
1091	 * next generate call will trigger a reseed.
1092	 */
1093	drbg->seeded = false;
1094
1095	__drbg_seed(drbg, &seedlist, true);
1096
1097	if (drbg->seeded)
1098		drbg->reseed_threshold = drbg_max_requests(drbg);
1099
1100unlock:
1101	mutex_unlock(&drbg->drbg_mutex);
1102
1103	memzero_explicit(entropy, entropylen);
1104}
1105
1106/*
1107 * Seeding or reseeding of the DRBG
1108 *
1109 * @drbg: DRBG state struct
1110 * @pers: personalization / additional information buffer
1111 * @reseed: 0 for initial seed process, 1 for reseeding
1112 *
1113 * return:
1114 *	0 on success
1115 *	error value otherwise
1116 */
1117static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
1118		     bool reseed)
1119{
1120	int ret;
1121	unsigned char entropy[((32 + 16) * 2)];
1122	unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
1123	struct drbg_string data1;
1124	LIST_HEAD(seedlist);
1125
1126	/* 9.1 / 9.2 / 9.3.1 step 3 */
1127	if (pers && pers->len > (drbg_max_addtl(drbg))) {
1128		pr_devel("DRBG: personalization string too long %zu\n",
1129			 pers->len);
1130		return -EINVAL;
1131	}
1132
1133	if (list_empty(&drbg->test_data.list)) {
1134		drbg_string_fill(&data1, drbg->test_data.buf,
1135				 drbg->test_data.len);
1136		pr_devel("DRBG: using test entropy\n");
1137	} else {
1138		/*
1139		 * Gather entropy equal to the security strength of the DRBG.
1140		 * With a derivation function, a nonce is required in addition
1141		 * to the entropy. A nonce must be at least 1/2 of the security
1142		 * strength of the DRBG in size. Thus, entropy + nonce is 3/2
1143		 * of the strength. The consideration of a nonce is only
1144		 * applicable during initial seeding.
1145		 */
1146		BUG_ON(!entropylen);
1147		if (!reseed)
1148			entropylen = ((entropylen + 1) / 2) * 3;
1149		BUG_ON((entropylen * 2) > sizeof(entropy));
1150
1151		/* Get seed from in-kernel /dev/urandom */
1152		ret = drbg_get_random_bytes(drbg, entropy, entropylen);
1153		if (ret)
1154			goto out;
1155
1156		if (!drbg->jent) {
1157			drbg_string_fill(&data1, entropy, entropylen);
1158			pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
1159				 entropylen);
1160		} else {
1161			/* Get seed from Jitter RNG */
1162			ret = crypto_rng_get_bytes(drbg->jent,
1163						   entropy + entropylen,
1164						   entropylen);
1165			if (ret) {
1166				pr_devel("DRBG: jent failed with %d\n", ret);
1167
1168				/*
1169				 * Do not treat the transient failure of the
1170				 * Jitter RNG as an error that needs to be
1171				 * reported. The combined number of the
1172				 * maximum reseed threshold times the maximum
1173				 * number of Jitter RNG transient errors is
1174				 * less than the reseed threshold required by
1175				 * SP800-90A allowing us to treat the
1176				 * transient errors as such.
1177				 *
1178				 * However, we mandate that at least the first
1179				 * seeding operation must succeed with the
1180				 * Jitter RNG.
1181				 */
1182				if (!reseed || ret != -EAGAIN)
1183					goto out;
1184			}
1185
1186			drbg_string_fill(&data1, entropy, entropylen * 2);
1187			pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
1188				 entropylen * 2);
1189		}
1190	}
1191	list_add_tail(&data1.list, &seedlist);
1192
1193	/*
1194	 * concatenation of entropy with personalization str / addtl input)
1195	 * the variable pers is directly handed in by the caller, so check its
1196	 * contents whether it is appropriate
1197	 */
1198	if (pers && pers->buf && 0 < pers->len) {
1199		list_add_tail(&pers->list, &seedlist);
1200		pr_devel("DRBG: using personalization string\n");
1201	}
1202
1203	if (!reseed) {
1204		memset(drbg->V, 0, drbg_statelen(drbg));
1205		memset(drbg->C, 0, drbg_statelen(drbg));
1206	}
1207
1208	ret = __drbg_seed(drbg, &seedlist, reseed);
1209
1210out:
1211	memzero_explicit(entropy, entropylen * 2);
1212
1213	return ret;
1214}
1215
1216/* Free all substructures in a DRBG state without the DRBG state structure */
1217static inline void drbg_dealloc_state(struct drbg_state *drbg)
1218{
1219	if (!drbg)
1220		return;
1221	kfree_sensitive(drbg->Vbuf);
1222	drbg->Vbuf = NULL;
1223	drbg->V = NULL;
1224	kfree_sensitive(drbg->Cbuf);
1225	drbg->Cbuf = NULL;
1226	drbg->C = NULL;
1227	kfree_sensitive(drbg->scratchpadbuf);
1228	drbg->scratchpadbuf = NULL;
1229	drbg->reseed_ctr = 0;
1230	drbg->d_ops = NULL;
1231	drbg->core = NULL;
1232	if (IS_ENABLED(CONFIG_CRYPTO_FIPS)) {
1233		kfree_sensitive(drbg->prev);
1234		drbg->prev = NULL;
1235		drbg->fips_primed = false;
1236	}
1237}
1238
1239/*
1240 * Allocate all sub-structures for a DRBG state.
1241 * The DRBG state structure must already be allocated.
1242 */
1243static inline int drbg_alloc_state(struct drbg_state *drbg)
1244{
1245	int ret = -ENOMEM;
1246	unsigned int sb_size = 0;
1247
1248	switch (drbg->core->flags & DRBG_TYPE_MASK) {
1249#ifdef CONFIG_CRYPTO_DRBG_HMAC
1250	case DRBG_HMAC:
1251		drbg->d_ops = &drbg_hmac_ops;
1252		break;
1253#endif /* CONFIG_CRYPTO_DRBG_HMAC */
1254#ifdef CONFIG_CRYPTO_DRBG_HASH
1255	case DRBG_HASH:
1256		drbg->d_ops = &drbg_hash_ops;
1257		break;
1258#endif /* CONFIG_CRYPTO_DRBG_HASH */
1259#ifdef CONFIG_CRYPTO_DRBG_CTR
1260	case DRBG_CTR:
1261		drbg->d_ops = &drbg_ctr_ops;
1262		break;
1263#endif /* CONFIG_CRYPTO_DRBG_CTR */
1264	default:
1265		ret = -EOPNOTSUPP;
1266		goto err;
1267	}
1268
1269	ret = drbg->d_ops->crypto_init(drbg);
1270	if (ret < 0)
 
 
 
1271		goto err;
1272
1273	drbg->Vbuf = kmalloc(drbg_statelen(drbg) + ret, GFP_KERNEL);
1274	if (!drbg->Vbuf) {
1275		ret = -ENOMEM;
1276		goto fini;
1277	}
1278	drbg->V = PTR_ALIGN(drbg->Vbuf, ret + 1);
1279	drbg->Cbuf = kmalloc(drbg_statelen(drbg) + ret, GFP_KERNEL);
1280	if (!drbg->Cbuf) {
1281		ret = -ENOMEM;
1282		goto fini;
1283	}
1284	drbg->C = PTR_ALIGN(drbg->Cbuf, ret + 1);
1285	/* scratchpad is only generated for CTR and Hash */
1286	if (drbg->core->flags & DRBG_HMAC)
1287		sb_size = 0;
1288	else if (drbg->core->flags & DRBG_CTR)
1289		sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg) + /* temp */
1290			  drbg_statelen(drbg) +	/* df_data */
1291			  drbg_blocklen(drbg) +	/* pad */
1292			  drbg_blocklen(drbg) +	/* iv */
1293			  drbg_statelen(drbg) + drbg_blocklen(drbg); /* temp */
1294	else
1295		sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg);
1296
1297	if (0 < sb_size) {
1298		drbg->scratchpadbuf = kzalloc(sb_size + ret, GFP_KERNEL);
1299		if (!drbg->scratchpadbuf) {
1300			ret = -ENOMEM;
1301			goto fini;
1302		}
1303		drbg->scratchpad = PTR_ALIGN(drbg->scratchpadbuf, ret + 1);
1304	}
1305
1306	if (IS_ENABLED(CONFIG_CRYPTO_FIPS)) {
1307		drbg->prev = kzalloc(drbg_sec_strength(drbg->core->flags),
1308				     GFP_KERNEL);
1309		if (!drbg->prev) {
1310			ret = -ENOMEM;
1311			goto fini;
1312		}
1313		drbg->fips_primed = false;
1314	}
1315
1316	return 0;
1317
1318fini:
1319	drbg->d_ops->crypto_fini(drbg);
1320err:
1321	drbg_dealloc_state(drbg);
1322	return ret;
1323}
1324
1325/*************************************************************************
1326 * DRBG interface functions
1327 *************************************************************************/
1328
1329/*
1330 * DRBG generate function as required by SP800-90A - this function
1331 * generates random numbers
1332 *
1333 * @drbg DRBG state handle
1334 * @buf Buffer where to store the random numbers -- the buffer must already
1335 *      be pre-allocated by caller
1336 * @buflen Length of output buffer - this value defines the number of random
1337 *	   bytes pulled from DRBG
1338 * @addtl Additional input that is mixed into state, may be NULL -- note
1339 *	  the entropy is pulled by the DRBG internally unconditionally
1340 *	  as defined in SP800-90A. The additional input is mixed into
1341 *	  the state in addition to the pulled entropy.
1342 *
1343 * return: 0 when all bytes are generated; < 0 in case of an error
1344 */
1345static int drbg_generate(struct drbg_state *drbg,
1346			 unsigned char *buf, unsigned int buflen,
1347			 struct drbg_string *addtl)
1348{
1349	int len = 0;
1350	LIST_HEAD(addtllist);
1351
1352	if (!drbg->core) {
1353		pr_devel("DRBG: not yet seeded\n");
1354		return -EINVAL;
1355	}
1356	if (0 == buflen || !buf) {
1357		pr_devel("DRBG: no output buffer provided\n");
1358		return -EINVAL;
1359	}
1360	if (addtl && NULL == addtl->buf && 0 < addtl->len) {
1361		pr_devel("DRBG: wrong format of additional information\n");
1362		return -EINVAL;
1363	}
1364
1365	/* 9.3.1 step 2 */
1366	len = -EINVAL;
1367	if (buflen > (drbg_max_request_bytes(drbg))) {
1368		pr_devel("DRBG: requested random numbers too large %u\n",
1369			 buflen);
1370		goto err;
1371	}
1372
1373	/* 9.3.1 step 3 is implicit with the chosen DRBG */
1374
1375	/* 9.3.1 step 4 */
1376	if (addtl && addtl->len > (drbg_max_addtl(drbg))) {
1377		pr_devel("DRBG: additional information string too long %zu\n",
1378			 addtl->len);
1379		goto err;
1380	}
1381	/* 9.3.1 step 5 is implicit with the chosen DRBG */
1382
1383	/*
1384	 * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented
1385	 * here. The spec is a bit convoluted here, we make it simpler.
1386	 */
1387	if (drbg->reseed_threshold < drbg->reseed_ctr)
1388		drbg->seeded = false;
1389
1390	if (drbg->pr || !drbg->seeded) {
1391		pr_devel("DRBG: reseeding before generation (prediction "
1392			 "resistance: %s, state %s)\n",
1393			 drbg->pr ? "true" : "false",
1394			 drbg->seeded ? "seeded" : "unseeded");
1395		/* 9.3.1 steps 7.1 through 7.3 */
1396		len = drbg_seed(drbg, addtl, true);
1397		if (len)
1398			goto err;
1399		/* 9.3.1 step 7.4 */
1400		addtl = NULL;
1401	}
1402
1403	if (addtl && 0 < addtl->len)
1404		list_add_tail(&addtl->list, &addtllist);
1405	/* 9.3.1 step 8 and 10 */
1406	len = drbg->d_ops->generate(drbg, buf, buflen, &addtllist);
1407
1408	/* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */
1409	drbg->reseed_ctr++;
1410	if (0 >= len)
1411		goto err;
1412
1413	/*
1414	 * Section 11.3.3 requires to re-perform self tests after some
1415	 * generated random numbers. The chosen value after which self
1416	 * test is performed is arbitrary, but it should be reasonable.
1417	 * However, we do not perform the self tests because of the following
1418	 * reasons: it is mathematically impossible that the initial self tests
1419	 * were successfully and the following are not. If the initial would
1420	 * pass and the following would not, the kernel integrity is violated.
1421	 * In this case, the entire kernel operation is questionable and it
1422	 * is unlikely that the integrity violation only affects the
1423	 * correct operation of the DRBG.
1424	 *
1425	 * Albeit the following code is commented out, it is provided in
1426	 * case somebody has a need to implement the test of 11.3.3.
1427	 */
1428#if 0
1429	if (drbg->reseed_ctr && !(drbg->reseed_ctr % 4096)) {
1430		int err = 0;
1431		pr_devel("DRBG: start to perform self test\n");
1432		if (drbg->core->flags & DRBG_HMAC)
1433			err = alg_test("drbg_pr_hmac_sha256",
1434				       "drbg_pr_hmac_sha256", 0, 0);
1435		else if (drbg->core->flags & DRBG_CTR)
1436			err = alg_test("drbg_pr_ctr_aes128",
1437				       "drbg_pr_ctr_aes128", 0, 0);
1438		else
1439			err = alg_test("drbg_pr_sha256",
1440				       "drbg_pr_sha256", 0, 0);
1441		if (err) {
1442			pr_err("DRBG: periodical self test failed\n");
1443			/*
1444			 * uninstantiate implies that from now on, only errors
1445			 * are returned when reusing this DRBG cipher handle
1446			 */
1447			drbg_uninstantiate(drbg);
1448			return 0;
1449		} else {
1450			pr_devel("DRBG: self test successful\n");
1451		}
1452	}
1453#endif
1454
1455	/*
1456	 * All operations were successful, return 0 as mandated by
1457	 * the kernel crypto API interface.
1458	 */
1459	len = 0;
1460err:
1461	return len;
1462}
1463
1464/*
1465 * Wrapper around drbg_generate which can pull arbitrary long strings
1466 * from the DRBG without hitting the maximum request limitation.
1467 *
1468 * Parameters: see drbg_generate
1469 * Return codes: see drbg_generate -- if one drbg_generate request fails,
1470 *		 the entire drbg_generate_long request fails
1471 */
1472static int drbg_generate_long(struct drbg_state *drbg,
1473			      unsigned char *buf, unsigned int buflen,
1474			      struct drbg_string *addtl)
1475{
1476	unsigned int len = 0;
1477	unsigned int slice = 0;
1478	do {
1479		int err = 0;
1480		unsigned int chunk = 0;
1481		slice = ((buflen - len) / drbg_max_request_bytes(drbg));
1482		chunk = slice ? drbg_max_request_bytes(drbg) : (buflen - len);
1483		mutex_lock(&drbg->drbg_mutex);
1484		err = drbg_generate(drbg, buf + len, chunk, addtl);
1485		mutex_unlock(&drbg->drbg_mutex);
1486		if (0 > err)
1487			return err;
1488		len += chunk;
1489	} while (slice > 0 && (len < buflen));
1490	return 0;
1491}
1492
1493static void drbg_schedule_async_seed(struct random_ready_callback *rdy)
1494{
1495	struct drbg_state *drbg = container_of(rdy, struct drbg_state,
1496					       random_ready);
1497
1498	schedule_work(&drbg->seed_work);
1499}
1500
1501static int drbg_prepare_hrng(struct drbg_state *drbg)
1502{
1503	int err;
1504
1505	/* We do not need an HRNG in test mode. */
1506	if (list_empty(&drbg->test_data.list))
1507		return 0;
1508
1509	drbg->jent = crypto_alloc_rng("jitterentropy_rng", 0, 0);
1510
1511	INIT_WORK(&drbg->seed_work, drbg_async_seed);
1512
1513	drbg->random_ready.owner = THIS_MODULE;
1514	drbg->random_ready.func = drbg_schedule_async_seed;
1515
1516	err = add_random_ready_callback(&drbg->random_ready);
1517
1518	switch (err) {
1519	case 0:
1520		break;
1521
1522	case -EALREADY:
1523		err = 0;
1524		fallthrough;
1525
1526	default:
1527		drbg->random_ready.func = NULL;
1528		return err;
1529	}
1530
 
 
1531	/*
1532	 * Require frequent reseeds until the seed source is fully
1533	 * initialized.
1534	 */
1535	drbg->reseed_threshold = 50;
1536
1537	return err;
1538}
1539
1540/*
1541 * DRBG instantiation function as required by SP800-90A - this function
1542 * sets up the DRBG handle, performs the initial seeding and all sanity
1543 * checks required by SP800-90A
1544 *
1545 * @drbg memory of state -- if NULL, new memory is allocated
1546 * @pers Personalization string that is mixed into state, may be NULL -- note
1547 *	 the entropy is pulled by the DRBG internally unconditionally
1548 *	 as defined in SP800-90A. The additional input is mixed into
1549 *	 the state in addition to the pulled entropy.
1550 * @coreref reference to core
1551 * @pr prediction resistance enabled
1552 *
1553 * return
1554 *	0 on success
1555 *	error value otherwise
1556 */
1557static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers,
1558			    int coreref, bool pr)
1559{
1560	int ret;
1561	bool reseed = true;
1562
1563	pr_devel("DRBG: Initializing DRBG core %d with prediction resistance "
1564		 "%s\n", coreref, pr ? "enabled" : "disabled");
1565	mutex_lock(&drbg->drbg_mutex);
1566
1567	/* 9.1 step 1 is implicit with the selected DRBG type */
1568
1569	/*
1570	 * 9.1 step 2 is implicit as caller can select prediction resistance
1571	 * and the flag is copied into drbg->flags --
1572	 * all DRBG types support prediction resistance
1573	 */
1574
1575	/* 9.1 step 4 is implicit in  drbg_sec_strength */
1576
1577	if (!drbg->core) {
1578		drbg->core = &drbg_cores[coreref];
1579		drbg->pr = pr;
1580		drbg->seeded = false;
1581		drbg->reseed_threshold = drbg_max_requests(drbg);
1582
1583		ret = drbg_alloc_state(drbg);
1584		if (ret)
1585			goto unlock;
1586
 
 
 
 
1587		ret = drbg_prepare_hrng(drbg);
1588		if (ret)
1589			goto free_everything;
1590
1591		if (IS_ERR(drbg->jent)) {
1592			ret = PTR_ERR(drbg->jent);
1593			drbg->jent = NULL;
1594			if (fips_enabled || ret != -ENOENT)
1595				goto free_everything;
1596			pr_info("DRBG: Continuing without Jitter RNG\n");
1597		}
1598
1599		reseed = false;
1600	}
1601
1602	ret = drbg_seed(drbg, pers, reseed);
1603
1604	if (ret && !reseed)
1605		goto free_everything;
1606
1607	mutex_unlock(&drbg->drbg_mutex);
1608	return ret;
1609
 
 
1610unlock:
1611	mutex_unlock(&drbg->drbg_mutex);
1612	return ret;
1613
1614free_everything:
1615	mutex_unlock(&drbg->drbg_mutex);
1616	drbg_uninstantiate(drbg);
1617	return ret;
1618}
1619
1620/*
1621 * DRBG uninstantiate function as required by SP800-90A - this function
1622 * frees all buffers and the DRBG handle
1623 *
1624 * @drbg DRBG state handle
1625 *
1626 * return
1627 *	0 on success
1628 */
1629static int drbg_uninstantiate(struct drbg_state *drbg)
1630{
1631	if (drbg->random_ready.func) {
1632		del_random_ready_callback(&drbg->random_ready);
1633		cancel_work_sync(&drbg->seed_work);
1634	}
1635
1636	if (!IS_ERR_OR_NULL(drbg->jent))
1637		crypto_free_rng(drbg->jent);
1638	drbg->jent = NULL;
 
1639
1640	if (drbg->d_ops)
1641		drbg->d_ops->crypto_fini(drbg);
1642	drbg_dealloc_state(drbg);
1643	/* no scrubbing of test_data -- this shall survive an uninstantiate */
1644	return 0;
1645}
1646
1647/*
1648 * Helper function for setting the test data in the DRBG
1649 *
1650 * @drbg DRBG state handle
1651 * @data test data
1652 * @len test data length
1653 */
1654static void drbg_kcapi_set_entropy(struct crypto_rng *tfm,
1655				   const u8 *data, unsigned int len)
1656{
1657	struct drbg_state *drbg = crypto_rng_ctx(tfm);
1658
1659	mutex_lock(&drbg->drbg_mutex);
1660	drbg_string_fill(&drbg->test_data, data, len);
1661	mutex_unlock(&drbg->drbg_mutex);
1662}
1663
1664/***************************************************************
1665 * Kernel crypto API cipher invocations requested by DRBG
1666 ***************************************************************/
1667
1668#if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
1669struct sdesc {
1670	struct shash_desc shash;
1671	char ctx[];
1672};
1673
1674static int drbg_init_hash_kernel(struct drbg_state *drbg)
1675{
1676	struct sdesc *sdesc;
1677	struct crypto_shash *tfm;
1678
1679	tfm = crypto_alloc_shash(drbg->core->backend_cra_name, 0, 0);
1680	if (IS_ERR(tfm)) {
1681		pr_info("DRBG: could not allocate digest TFM handle: %s\n",
1682				drbg->core->backend_cra_name);
1683		return PTR_ERR(tfm);
1684	}
1685	BUG_ON(drbg_blocklen(drbg) != crypto_shash_digestsize(tfm));
1686	sdesc = kzalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm),
1687			GFP_KERNEL);
1688	if (!sdesc) {
1689		crypto_free_shash(tfm);
1690		return -ENOMEM;
1691	}
1692
1693	sdesc->shash.tfm = tfm;
 
1694	drbg->priv_data = sdesc;
1695
1696	return crypto_shash_alignmask(tfm);
1697}
1698
1699static int drbg_fini_hash_kernel(struct drbg_state *drbg)
1700{
1701	struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
1702	if (sdesc) {
1703		crypto_free_shash(sdesc->shash.tfm);
1704		kfree_sensitive(sdesc);
1705	}
1706	drbg->priv_data = NULL;
1707	return 0;
1708}
1709
1710static void drbg_kcapi_hmacsetkey(struct drbg_state *drbg,
1711				  const unsigned char *key)
1712{
1713	struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
1714
1715	crypto_shash_setkey(sdesc->shash.tfm, key, drbg_statelen(drbg));
1716}
1717
1718static int drbg_kcapi_hash(struct drbg_state *drbg, unsigned char *outval,
1719			   const struct list_head *in)
1720{
1721	struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
1722	struct drbg_string *input = NULL;
1723
 
 
1724	crypto_shash_init(&sdesc->shash);
1725	list_for_each_entry(input, in, list)
1726		crypto_shash_update(&sdesc->shash, input->buf, input->len);
1727	return crypto_shash_final(&sdesc->shash, outval);
1728}
1729#endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
1730
1731#ifdef CONFIG_CRYPTO_DRBG_CTR
1732static int drbg_fini_sym_kernel(struct drbg_state *drbg)
1733{
1734	struct crypto_cipher *tfm =
1735		(struct crypto_cipher *)drbg->priv_data;
1736	if (tfm)
1737		crypto_free_cipher(tfm);
1738	drbg->priv_data = NULL;
1739
1740	if (drbg->ctr_handle)
1741		crypto_free_skcipher(drbg->ctr_handle);
1742	drbg->ctr_handle = NULL;
1743
1744	if (drbg->ctr_req)
1745		skcipher_request_free(drbg->ctr_req);
1746	drbg->ctr_req = NULL;
1747
1748	kfree(drbg->outscratchpadbuf);
1749	drbg->outscratchpadbuf = NULL;
1750
1751	return 0;
1752}
1753
1754static int drbg_init_sym_kernel(struct drbg_state *drbg)
1755{
 
1756	struct crypto_cipher *tfm;
1757	struct crypto_skcipher *sk_tfm;
1758	struct skcipher_request *req;
1759	unsigned int alignmask;
1760	char ctr_name[CRYPTO_MAX_ALG_NAME];
1761
1762	tfm = crypto_alloc_cipher(drbg->core->backend_cra_name, 0, 0);
1763	if (IS_ERR(tfm)) {
1764		pr_info("DRBG: could not allocate cipher TFM handle: %s\n",
1765				drbg->core->backend_cra_name);
1766		return PTR_ERR(tfm);
1767	}
1768	BUG_ON(drbg_blocklen(drbg) != crypto_cipher_blocksize(tfm));
1769	drbg->priv_data = tfm;
1770
1771	if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)",
1772	    drbg->core->backend_cra_name) >= CRYPTO_MAX_ALG_NAME) {
1773		drbg_fini_sym_kernel(drbg);
1774		return -EINVAL;
1775	}
1776	sk_tfm = crypto_alloc_skcipher(ctr_name, 0, 0);
1777	if (IS_ERR(sk_tfm)) {
1778		pr_info("DRBG: could not allocate CTR cipher TFM handle: %s\n",
1779				ctr_name);
1780		drbg_fini_sym_kernel(drbg);
1781		return PTR_ERR(sk_tfm);
1782	}
1783	drbg->ctr_handle = sk_tfm;
1784	crypto_init_wait(&drbg->ctr_wait);
1785
1786	req = skcipher_request_alloc(sk_tfm, GFP_KERNEL);
1787	if (!req) {
1788		pr_info("DRBG: could not allocate request queue\n");
1789		drbg_fini_sym_kernel(drbg);
1790		return -ENOMEM;
1791	}
1792	drbg->ctr_req = req;
1793	skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
1794						CRYPTO_TFM_REQ_MAY_SLEEP,
1795					crypto_req_done, &drbg->ctr_wait);
1796
1797	alignmask = crypto_skcipher_alignmask(sk_tfm);
1798	drbg->outscratchpadbuf = kmalloc(DRBG_OUTSCRATCHLEN + alignmask,
1799					 GFP_KERNEL);
1800	if (!drbg->outscratchpadbuf) {
1801		drbg_fini_sym_kernel(drbg);
1802		return -ENOMEM;
1803	}
1804	drbg->outscratchpad = (u8 *)PTR_ALIGN(drbg->outscratchpadbuf,
1805					      alignmask + 1);
1806
1807	sg_init_table(&drbg->sg_in, 1);
1808	sg_init_one(&drbg->sg_out, drbg->outscratchpad, DRBG_OUTSCRATCHLEN);
1809
1810	return alignmask;
1811}
1812
1813static void drbg_kcapi_symsetkey(struct drbg_state *drbg,
1814				 const unsigned char *key)
1815{
1816	struct crypto_cipher *tfm =
1817		(struct crypto_cipher *)drbg->priv_data;
1818
1819	crypto_cipher_setkey(tfm, key, (drbg_keylen(drbg)));
 
 
1820}
1821
1822static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval,
1823			  const struct drbg_string *in)
1824{
1825	struct crypto_cipher *tfm =
1826		(struct crypto_cipher *)drbg->priv_data;
1827
 
1828	/* there is only component in *in */
1829	BUG_ON(in->len < drbg_blocklen(drbg));
1830	crypto_cipher_encrypt_one(tfm, outval, in->buf);
1831	return 0;
1832}
1833
1834static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
1835			      u8 *inbuf, u32 inlen,
1836			      u8 *outbuf, u32 outlen)
1837{
1838	struct scatterlist *sg_in = &drbg->sg_in, *sg_out = &drbg->sg_out;
1839	u32 scratchpad_use = min_t(u32, outlen, DRBG_OUTSCRATCHLEN);
1840	int ret;
1841
1842	if (inbuf) {
1843		/* Use caller-provided input buffer */
1844		sg_set_buf(sg_in, inbuf, inlen);
1845	} else {
1846		/* Use scratchpad for in-place operation */
1847		inlen = scratchpad_use;
1848		memset(drbg->outscratchpad, 0, scratchpad_use);
1849		sg_set_buf(sg_in, drbg->outscratchpad, scratchpad_use);
1850	}
1851
1852	while (outlen) {
1853		u32 cryptlen = min3(inlen, outlen, (u32)DRBG_OUTSCRATCHLEN);
1854
1855		/* Output buffer may not be valid for SGL, use scratchpad */
1856		skcipher_request_set_crypt(drbg->ctr_req, sg_in, sg_out,
1857					   cryptlen, drbg->V);
1858		ret = crypto_wait_req(crypto_skcipher_encrypt(drbg->ctr_req),
1859					&drbg->ctr_wait);
1860		if (ret)
1861			goto out;
1862
1863		crypto_init_wait(&drbg->ctr_wait);
1864
1865		memcpy(outbuf, drbg->outscratchpad, cryptlen);
1866		memzero_explicit(drbg->outscratchpad, cryptlen);
1867
1868		outlen -= cryptlen;
1869		outbuf += cryptlen;
1870	}
1871	ret = 0;
1872
1873out:
1874	return ret;
1875}
1876#endif /* CONFIG_CRYPTO_DRBG_CTR */
1877
1878/***************************************************************
1879 * Kernel crypto API interface to register DRBG
1880 ***************************************************************/
1881
1882/*
1883 * Look up the DRBG flags by given kernel crypto API cra_name
1884 * The code uses the drbg_cores definition to do this
1885 *
1886 * @cra_name kernel crypto API cra_name
1887 * @coreref reference to integer which is filled with the pointer to
1888 *  the applicable core
1889 * @pr reference for setting prediction resistance
1890 *
1891 * return: flags
1892 */
1893static inline void drbg_convert_tfm_core(const char *cra_driver_name,
1894					 int *coreref, bool *pr)
1895{
1896	int i = 0;
1897	size_t start = 0;
1898	int len = 0;
1899
1900	*pr = true;
1901	/* disassemble the names */
1902	if (!memcmp(cra_driver_name, "drbg_nopr_", 10)) {
1903		start = 10;
1904		*pr = false;
1905	} else if (!memcmp(cra_driver_name, "drbg_pr_", 8)) {
1906		start = 8;
1907	} else {
1908		return;
1909	}
1910
1911	/* remove the first part */
1912	len = strlen(cra_driver_name) - start;
1913	for (i = 0; ARRAY_SIZE(drbg_cores) > i; i++) {
1914		if (!memcmp(cra_driver_name + start, drbg_cores[i].cra_name,
1915			    len)) {
1916			*coreref = i;
1917			return;
1918		}
1919	}
1920}
1921
1922static int drbg_kcapi_init(struct crypto_tfm *tfm)
1923{
1924	struct drbg_state *drbg = crypto_tfm_ctx(tfm);
1925
1926	mutex_init(&drbg->drbg_mutex);
1927
1928	return 0;
1929}
1930
1931static void drbg_kcapi_cleanup(struct crypto_tfm *tfm)
1932{
1933	drbg_uninstantiate(crypto_tfm_ctx(tfm));
1934}
1935
1936/*
1937 * Generate random numbers invoked by the kernel crypto API:
1938 * The API of the kernel crypto API is extended as follows:
1939 *
1940 * src is additional input supplied to the RNG.
1941 * slen is the length of src.
1942 * dst is the output buffer where random data is to be stored.
1943 * dlen is the length of dst.
1944 */
1945static int drbg_kcapi_random(struct crypto_rng *tfm,
1946			     const u8 *src, unsigned int slen,
1947			     u8 *dst, unsigned int dlen)
1948{
1949	struct drbg_state *drbg = crypto_rng_ctx(tfm);
1950	struct drbg_string *addtl = NULL;
1951	struct drbg_string string;
1952
1953	if (slen) {
1954		/* linked list variable is now local to allow modification */
1955		drbg_string_fill(&string, src, slen);
1956		addtl = &string;
1957	}
1958
1959	return drbg_generate_long(drbg, dst, dlen, addtl);
1960}
1961
1962/*
1963 * Seed the DRBG invoked by the kernel crypto API
1964 */
1965static int drbg_kcapi_seed(struct crypto_rng *tfm,
1966			   const u8 *seed, unsigned int slen)
1967{
1968	struct drbg_state *drbg = crypto_rng_ctx(tfm);
1969	struct crypto_tfm *tfm_base = crypto_rng_tfm(tfm);
1970	bool pr = false;
1971	struct drbg_string string;
1972	struct drbg_string *seed_string = NULL;
1973	int coreref = 0;
1974
1975	drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base), &coreref,
1976			      &pr);
1977	if (0 < slen) {
1978		drbg_string_fill(&string, seed, slen);
1979		seed_string = &string;
1980	}
1981
1982	return drbg_instantiate(drbg, seed_string, coreref, pr);
1983}
1984
1985/***************************************************************
1986 * Kernel module: code to load the module
1987 ***************************************************************/
1988
1989/*
1990 * Tests as defined in 11.3.2 in addition to the cipher tests: testing
1991 * of the error handling.
1992 *
1993 * Note: testing of failing seed source as defined in 11.3.2 is not applicable
1994 * as seed source of get_random_bytes does not fail.
1995 *
1996 * Note 2: There is no sensible way of testing the reseed counter
1997 * enforcement, so skip it.
1998 */
1999static inline int __init drbg_healthcheck_sanity(void)
2000{
2001	int len = 0;
2002#define OUTBUFLEN 16
2003	unsigned char buf[OUTBUFLEN];
2004	struct drbg_state *drbg = NULL;
2005	int ret = -EFAULT;
2006	int rc = -EFAULT;
2007	bool pr = false;
2008	int coreref = 0;
2009	struct drbg_string addtl;
2010	size_t max_addtllen, max_request_bytes;
2011
2012	/* only perform test in FIPS mode */
2013	if (!fips_enabled)
2014		return 0;
2015
2016#ifdef CONFIG_CRYPTO_DRBG_CTR
2017	drbg_convert_tfm_core("drbg_nopr_ctr_aes128", &coreref, &pr);
2018#elif defined CONFIG_CRYPTO_DRBG_HASH
2019	drbg_convert_tfm_core("drbg_nopr_sha256", &coreref, &pr);
2020#else
2021	drbg_convert_tfm_core("drbg_nopr_hmac_sha256", &coreref, &pr);
2022#endif
2023
2024	drbg = kzalloc(sizeof(struct drbg_state), GFP_KERNEL);
2025	if (!drbg)
2026		return -ENOMEM;
2027
2028	mutex_init(&drbg->drbg_mutex);
2029	drbg->core = &drbg_cores[coreref];
2030	drbg->reseed_threshold = drbg_max_requests(drbg);
2031
2032	/*
2033	 * if the following tests fail, it is likely that there is a buffer
2034	 * overflow as buf is much smaller than the requested or provided
2035	 * string lengths -- in case the error handling does not succeed
2036	 * we may get an OOPS. And we want to get an OOPS as this is a
2037	 * grave bug.
2038	 */
2039
 
 
 
 
 
 
2040	max_addtllen = drbg_max_addtl(drbg);
2041	max_request_bytes = drbg_max_request_bytes(drbg);
2042	drbg_string_fill(&addtl, buf, max_addtllen + 1);
2043	/* overflow addtllen with additonal info string */
2044	len = drbg_generate(drbg, buf, OUTBUFLEN, &addtl);
2045	BUG_ON(0 < len);
2046	/* overflow max_bits */
2047	len = drbg_generate(drbg, buf, (max_request_bytes + 1), NULL);
2048	BUG_ON(0 < len);
 
2049
2050	/* overflow max addtllen with personalization string */
2051	ret = drbg_seed(drbg, &addtl, false);
2052	BUG_ON(0 == ret);
2053	/* all tests passed */
2054	rc = 0;
2055
2056	pr_devel("DRBG: Sanity tests for failure code paths successfully "
2057		 "completed\n");
2058
2059	kfree(drbg);
 
 
2060	return rc;
2061}
2062
2063static struct rng_alg drbg_algs[22];
2064
2065/*
2066 * Fill the array drbg_algs used to register the different DRBGs
2067 * with the kernel crypto API. To fill the array, the information
2068 * from drbg_cores[] is used.
2069 */
2070static inline void __init drbg_fill_array(struct rng_alg *alg,
2071					  const struct drbg_core *core, int pr)
2072{
2073	int pos = 0;
2074	static int priority = 200;
2075
2076	memcpy(alg->base.cra_name, "stdrng", 6);
2077	if (pr) {
2078		memcpy(alg->base.cra_driver_name, "drbg_pr_", 8);
2079		pos = 8;
2080	} else {
2081		memcpy(alg->base.cra_driver_name, "drbg_nopr_", 10);
2082		pos = 10;
2083	}
2084	memcpy(alg->base.cra_driver_name + pos, core->cra_name,
2085	       strlen(core->cra_name));
2086
2087	alg->base.cra_priority = priority;
2088	priority++;
2089	/*
2090	 * If FIPS mode enabled, the selected DRBG shall have the
2091	 * highest cra_priority over other stdrng instances to ensure
2092	 * it is selected.
2093	 */
2094	if (fips_enabled)
2095		alg->base.cra_priority += 200;
2096
2097	alg->base.cra_ctxsize 	= sizeof(struct drbg_state);
2098	alg->base.cra_module	= THIS_MODULE;
2099	alg->base.cra_init	= drbg_kcapi_init;
2100	alg->base.cra_exit	= drbg_kcapi_cleanup;
2101	alg->generate		= drbg_kcapi_random;
2102	alg->seed		= drbg_kcapi_seed;
2103	alg->set_ent		= drbg_kcapi_set_entropy;
2104	alg->seedsize		= 0;
2105}
2106
2107static int __init drbg_init(void)
2108{
2109	unsigned int i = 0; /* pointer to drbg_algs */
2110	unsigned int j = 0; /* pointer to drbg_cores */
2111	int ret;
2112
2113	ret = drbg_healthcheck_sanity();
2114	if (ret)
2115		return ret;
2116
2117	if (ARRAY_SIZE(drbg_cores) * 2 > ARRAY_SIZE(drbg_algs)) {
2118		pr_info("DRBG: Cannot register all DRBG types"
2119			"(slots needed: %zu, slots available: %zu)\n",
2120			ARRAY_SIZE(drbg_cores) * 2, ARRAY_SIZE(drbg_algs));
2121		return -EFAULT;
2122	}
2123
2124	/*
2125	 * each DRBG definition can be used with PR and without PR, thus
2126	 * we instantiate each DRBG in drbg_cores[] twice.
2127	 *
2128	 * As the order of placing them into the drbg_algs array matters
2129	 * (the later DRBGs receive a higher cra_priority) we register the
2130	 * prediction resistance DRBGs first as the should not be too
2131	 * interesting.
2132	 */
2133	for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
2134		drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 1);
2135	for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
2136		drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 0);
2137	return crypto_register_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
2138}
2139
2140static void __exit drbg_exit(void)
2141{
2142	crypto_unregister_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
2143}
2144
2145subsys_initcall(drbg_init);
2146module_exit(drbg_exit);
2147#ifndef CRYPTO_DRBG_HASH_STRING
2148#define CRYPTO_DRBG_HASH_STRING ""
2149#endif
2150#ifndef CRYPTO_DRBG_HMAC_STRING
2151#define CRYPTO_DRBG_HMAC_STRING ""
2152#endif
2153#ifndef CRYPTO_DRBG_CTR_STRING
2154#define CRYPTO_DRBG_CTR_STRING ""
2155#endif
2156MODULE_LICENSE("GPL");
2157MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
2158MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) "
2159		   "using following cores: "
2160		   CRYPTO_DRBG_HASH_STRING
2161		   CRYPTO_DRBG_HMAC_STRING
2162		   CRYPTO_DRBG_CTR_STRING);
2163MODULE_ALIAS_CRYPTO("stdrng");