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#include <linux/string_choices.h>
 105
 106/***************************************************************
 107 * Backend cipher definitions available to DRBG
 108 ***************************************************************/
 109
 110/*
 111 * The order of the DRBG definitions here matter: every DRBG is registered
 112 * as stdrng. Each DRBG receives an increasing cra_priority values the later
 113 * they are defined in this array (see drbg_fill_array).
 114 *
 115 * HMAC DRBGs are favored over Hash DRBGs over CTR DRBGs, and the
 116 * HMAC-SHA512 / SHA256 / AES 256 over other ciphers. Thus, the
 117 * favored DRBGs are the latest entries in this array.
 118 */
 119static const struct drbg_core drbg_cores[] = {
 120#ifdef CONFIG_CRYPTO_DRBG_CTR
 121	{
 122		.flags = DRBG_CTR | DRBG_STRENGTH128,
 123		.statelen = 32, /* 256 bits as defined in 10.2.1 */
 124		.blocklen_bytes = 16,
 125		.cra_name = "ctr_aes128",
 126		.backend_cra_name = "aes",
 127	}, {
 128		.flags = DRBG_CTR | DRBG_STRENGTH192,
 129		.statelen = 40, /* 320 bits as defined in 10.2.1 */
 130		.blocklen_bytes = 16,
 131		.cra_name = "ctr_aes192",
 132		.backend_cra_name = "aes",
 133	}, {
 134		.flags = DRBG_CTR | DRBG_STRENGTH256,
 135		.statelen = 48, /* 384 bits as defined in 10.2.1 */
 136		.blocklen_bytes = 16,
 137		.cra_name = "ctr_aes256",
 138		.backend_cra_name = "aes",
 139	},
 140#endif /* CONFIG_CRYPTO_DRBG_CTR */
 141#ifdef CONFIG_CRYPTO_DRBG_HASH
 142	{
 
 
 
 
 
 
 143		.flags = DRBG_HASH | DRBG_STRENGTH256,
 144		.statelen = 111, /* 888 bits */
 145		.blocklen_bytes = 48,
 146		.cra_name = "sha384",
 147		.backend_cra_name = "sha384",
 148	}, {
 149		.flags = DRBG_HASH | DRBG_STRENGTH256,
 150		.statelen = 111, /* 888 bits */
 151		.blocklen_bytes = 64,
 152		.cra_name = "sha512",
 153		.backend_cra_name = "sha512",
 154	}, {
 155		.flags = DRBG_HASH | DRBG_STRENGTH256,
 156		.statelen = 55, /* 440 bits */
 157		.blocklen_bytes = 32,
 158		.cra_name = "sha256",
 159		.backend_cra_name = "sha256",
 160	},
 161#endif /* CONFIG_CRYPTO_DRBG_HASH */
 162#ifdef CONFIG_CRYPTO_DRBG_HMAC
 163	{
 
 
 
 
 
 
 164		.flags = DRBG_HMAC | DRBG_STRENGTH256,
 165		.statelen = 48, /* block length of cipher */
 166		.blocklen_bytes = 48,
 167		.cra_name = "hmac_sha384",
 168		.backend_cra_name = "hmac(sha384)",
 169	}, {
 170		.flags = DRBG_HMAC | DRBG_STRENGTH256,
 171		.statelen = 32, /* block length of cipher */
 172		.blocklen_bytes = 32,
 173		.cra_name = "hmac_sha256",
 174		.backend_cra_name = "hmac(sha256)",
 175	}, {
 176		.flags = DRBG_HMAC | DRBG_STRENGTH256,
 177		.statelen = 64, /* block length of cipher */
 178		.blocklen_bytes = 64,
 179		.cra_name = "hmac_sha512",
 180		.backend_cra_name = "hmac(sha512)",
 181	},
 182#endif /* CONFIG_CRYPTO_DRBG_HMAC */
 183};
 184
 185static int drbg_uninstantiate(struct drbg_state *drbg);
 186
 187/******************************************************************
 188 * Generic helper functions
 189 ******************************************************************/
 190
 191/*
 192 * Return strength of DRBG according to SP800-90A section 8.4
 193 *
 194 * @flags DRBG flags reference
 195 *
 196 * Return: normalized strength in *bytes* value or 32 as default
 197 *	   to counter programming errors
 198 */
 199static inline unsigned short drbg_sec_strength(drbg_flag_t flags)
 200{
 201	switch (flags & DRBG_STRENGTH_MASK) {
 202	case DRBG_STRENGTH128:
 203		return 16;
 204	case DRBG_STRENGTH192:
 205		return 24;
 206	case DRBG_STRENGTH256:
 207		return 32;
 208	default:
 209		return 32;
 210	}
 211}
 212
 213/*
 214 * FIPS 140-2 continuous self test for the noise source
 215 * The test is performed on the noise source input data. Thus, the function
 216 * implicitly knows the size of the buffer to be equal to the security
 217 * strength.
 218 *
 219 * Note, this function disregards the nonce trailing the entropy data during
 220 * initial seeding.
 221 *
 222 * drbg->drbg_mutex must have been taken.
 223 *
 224 * @drbg DRBG handle
 225 * @entropy buffer of seed data to be checked
 226 *
 227 * return:
 228 *	0 on success
 229 *	-EAGAIN on when the CTRNG is not yet primed
 230 *	< 0 on error
 231 */
 232static int drbg_fips_continuous_test(struct drbg_state *drbg,
 233				     const unsigned char *entropy)
 234{
 235	unsigned short entropylen = drbg_sec_strength(drbg->core->flags);
 236	int ret = 0;
 237
 238	if (!IS_ENABLED(CONFIG_CRYPTO_FIPS))
 239		return 0;
 240
 241	/* skip test if we test the overall system */
 242	if (list_empty(&drbg->test_data.list))
 243		return 0;
 244	/* only perform test in FIPS mode */
 245	if (!fips_enabled)
 246		return 0;
 247
 248	if (!drbg->fips_primed) {
 249		/* Priming of FIPS test */
 250		memcpy(drbg->prev, entropy, entropylen);
 251		drbg->fips_primed = true;
 252		/* priming: another round is needed */
 253		return -EAGAIN;
 254	}
 255	ret = memcmp(drbg->prev, entropy, entropylen);
 256	if (!ret)
 257		panic("DRBG continuous self test failed\n");
 258	memcpy(drbg->prev, entropy, entropylen);
 259
 260	/* the test shall pass when the two values are not equal */
 261	return 0;
 262}
 263
 264/*
 265 * Convert an integer into a byte representation of this integer.
 266 * The byte representation is big-endian
 267 *
 268 * @val value to be converted
 269 * @buf buffer holding the converted integer -- caller must ensure that
 270 *      buffer size is at least 32 bit
 271 */
 272#if (defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR))
 273static inline void drbg_cpu_to_be32(__u32 val, unsigned char *buf)
 274{
 275	struct s {
 276		__be32 conv;
 277	};
 278	struct s *conversion = (struct s *) buf;
 279
 280	conversion->conv = cpu_to_be32(val);
 281}
 282#endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */
 283
 284/******************************************************************
 285 * CTR DRBG callback functions
 286 ******************************************************************/
 287
 288#ifdef CONFIG_CRYPTO_DRBG_CTR
 289#define CRYPTO_DRBG_CTR_STRING "CTR "
 290MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes256");
 291MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes256");
 292MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes192");
 293MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes192");
 294MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes128");
 295MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes128");
 296
 297static void drbg_kcapi_symsetkey(struct drbg_state *drbg,
 298				 const unsigned char *key);
 299static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval,
 300			  const struct drbg_string *in);
 301static int drbg_init_sym_kernel(struct drbg_state *drbg);
 302static int drbg_fini_sym_kernel(struct drbg_state *drbg);
 303static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
 304			      u8 *inbuf, u32 inbuflen,
 305			      u8 *outbuf, u32 outlen);
 306#define DRBG_OUTSCRATCHLEN 256
 307
 308/* BCC function for CTR DRBG as defined in 10.4.3 */
 309static int drbg_ctr_bcc(struct drbg_state *drbg,
 310			unsigned char *out, const unsigned char *key,
 311			struct list_head *in)
 312{
 313	int ret = 0;
 314	struct drbg_string *curr = NULL;
 315	struct drbg_string data;
 316	short cnt = 0;
 317
 318	drbg_string_fill(&data, out, drbg_blocklen(drbg));
 319
 320	/* 10.4.3 step 2 / 4 */
 321	drbg_kcapi_symsetkey(drbg, key);
 322	list_for_each_entry(curr, in, list) {
 323		const unsigned char *pos = curr->buf;
 324		size_t len = curr->len;
 325		/* 10.4.3 step 4.1 */
 326		while (len) {
 327			/* 10.4.3 step 4.2 */
 328			if (drbg_blocklen(drbg) == cnt) {
 329				cnt = 0;
 330				ret = drbg_kcapi_sym(drbg, out, &data);
 331				if (ret)
 332					return ret;
 333			}
 334			out[cnt] ^= *pos;
 335			pos++;
 336			cnt++;
 337			len--;
 338		}
 339	}
 340	/* 10.4.3 step 4.2 for last block */
 341	if (cnt)
 342		ret = drbg_kcapi_sym(drbg, out, &data);
 343
 344	return ret;
 345}
 346
 347/*
 348 * scratchpad usage: drbg_ctr_update is interlinked with drbg_ctr_df
 349 * (and drbg_ctr_bcc, but this function does not need any temporary buffers),
 350 * the scratchpad is used as follows:
 351 * drbg_ctr_update:
 352 *	temp
 353 *		start: drbg->scratchpad
 354 *		length: drbg_statelen(drbg) + drbg_blocklen(drbg)
 355 *			note: the cipher writing into this variable works
 356 *			blocklen-wise. Now, when the statelen is not a multiple
 357 *			of blocklen, the generateion loop below "spills over"
 358 *			by at most blocklen. Thus, we need to give sufficient
 359 *			memory.
 360 *	df_data
 361 *		start: drbg->scratchpad +
 362 *				drbg_statelen(drbg) + drbg_blocklen(drbg)
 363 *		length: drbg_statelen(drbg)
 364 *
 365 * drbg_ctr_df:
 366 *	pad
 367 *		start: df_data + drbg_statelen(drbg)
 368 *		length: drbg_blocklen(drbg)
 369 *	iv
 370 *		start: pad + drbg_blocklen(drbg)
 371 *		length: drbg_blocklen(drbg)
 372 *	temp
 373 *		start: iv + drbg_blocklen(drbg)
 374 *		length: drbg_satelen(drbg) + drbg_blocklen(drbg)
 375 *			note: temp is the buffer that the BCC function operates
 376 *			on. BCC operates blockwise. drbg_statelen(drbg)
 377 *			is sufficient when the DRBG state length is a multiple
 378 *			of the block size. For AES192 (and maybe other ciphers)
 379 *			this is not correct and the length for temp is
 380 *			insufficient (yes, that also means for such ciphers,
 381 *			the final output of all BCC rounds are truncated).
 382 *			Therefore, add drbg_blocklen(drbg) to cover all
 383 *			possibilities.
 384 */
 385
 386/* Derivation Function for CTR DRBG as defined in 10.4.2 */
 387static int drbg_ctr_df(struct drbg_state *drbg,
 388		       unsigned char *df_data, size_t bytes_to_return,
 389		       struct list_head *seedlist)
 390{
 391	int ret = -EFAULT;
 392	unsigned char L_N[8];
 393	/* S3 is input */
 394	struct drbg_string S1, S2, S4, cipherin;
 395	LIST_HEAD(bcc_list);
 396	unsigned char *pad = df_data + drbg_statelen(drbg);
 397	unsigned char *iv = pad + drbg_blocklen(drbg);
 398	unsigned char *temp = iv + drbg_blocklen(drbg);
 399	size_t padlen = 0;
 400	unsigned int templen = 0;
 401	/* 10.4.2 step 7 */
 402	unsigned int i = 0;
 403	/* 10.4.2 step 8 */
 404	const unsigned char *K = (unsigned char *)
 405			   "\x00\x01\x02\x03\x04\x05\x06\x07"
 406			   "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
 407			   "\x10\x11\x12\x13\x14\x15\x16\x17"
 408			   "\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f";
 409	unsigned char *X;
 410	size_t generated_len = 0;
 411	size_t inputlen = 0;
 412	struct drbg_string *seed = NULL;
 413
 414	memset(pad, 0, drbg_blocklen(drbg));
 415	memset(iv, 0, drbg_blocklen(drbg));
 416
 417	/* 10.4.2 step 1 is implicit as we work byte-wise */
 418
 419	/* 10.4.2 step 2 */
 420	if ((512/8) < bytes_to_return)
 421		return -EINVAL;
 422
 423	/* 10.4.2 step 2 -- calculate the entire length of all input data */
 424	list_for_each_entry(seed, seedlist, list)
 425		inputlen += seed->len;
 426	drbg_cpu_to_be32(inputlen, &L_N[0]);
 427
 428	/* 10.4.2 step 3 */
 429	drbg_cpu_to_be32(bytes_to_return, &L_N[4]);
 430
 431	/* 10.4.2 step 5: length is L_N, input_string, one byte, padding */
 432	padlen = (inputlen + sizeof(L_N) + 1) % (drbg_blocklen(drbg));
 433	/* wrap the padlen appropriately */
 434	if (padlen)
 435		padlen = drbg_blocklen(drbg) - padlen;
 436	/*
 437	 * pad / padlen contains the 0x80 byte and the following zero bytes.
 438	 * As the calculated padlen value only covers the number of zero
 439	 * bytes, this value has to be incremented by one for the 0x80 byte.
 440	 */
 441	padlen++;
 442	pad[0] = 0x80;
 443
 444	/* 10.4.2 step 4 -- first fill the linked list and then order it */
 445	drbg_string_fill(&S1, iv, drbg_blocklen(drbg));
 446	list_add_tail(&S1.list, &bcc_list);
 447	drbg_string_fill(&S2, L_N, sizeof(L_N));
 448	list_add_tail(&S2.list, &bcc_list);
 449	list_splice_tail(seedlist, &bcc_list);
 450	drbg_string_fill(&S4, pad, padlen);
 451	list_add_tail(&S4.list, &bcc_list);
 452
 453	/* 10.4.2 step 9 */
 454	while (templen < (drbg_keylen(drbg) + (drbg_blocklen(drbg)))) {
 455		/*
 456		 * 10.4.2 step 9.1 - the padding is implicit as the buffer
 457		 * holds zeros after allocation -- even the increment of i
 458		 * is irrelevant as the increment remains within length of i
 459		 */
 460		drbg_cpu_to_be32(i, iv);
 461		/* 10.4.2 step 9.2 -- BCC and concatenation with temp */
 462		ret = drbg_ctr_bcc(drbg, temp + templen, K, &bcc_list);
 463		if (ret)
 464			goto out;
 465		/* 10.4.2 step 9.3 */
 466		i++;
 467		templen += drbg_blocklen(drbg);
 468	}
 469
 470	/* 10.4.2 step 11 */
 471	X = temp + (drbg_keylen(drbg));
 472	drbg_string_fill(&cipherin, X, drbg_blocklen(drbg));
 473
 474	/* 10.4.2 step 12: overwriting of outval is implemented in next step */
 475
 476	/* 10.4.2 step 13 */
 477	drbg_kcapi_symsetkey(drbg, temp);
 478	while (generated_len < bytes_to_return) {
 479		short blocklen = 0;
 480		/*
 481		 * 10.4.2 step 13.1: the truncation of the key length is
 482		 * implicit as the key is only drbg_blocklen in size based on
 483		 * the implementation of the cipher function callback
 484		 */
 485		ret = drbg_kcapi_sym(drbg, X, &cipherin);
 486		if (ret)
 487			goto out;
 488		blocklen = (drbg_blocklen(drbg) <
 489				(bytes_to_return - generated_len)) ?
 490			    drbg_blocklen(drbg) :
 491				(bytes_to_return - generated_len);
 492		/* 10.4.2 step 13.2 and 14 */
 493		memcpy(df_data + generated_len, X, blocklen);
 494		generated_len += blocklen;
 495	}
 496
 497	ret = 0;
 498
 499out:
 500	memset(iv, 0, drbg_blocklen(drbg));
 501	memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
 502	memset(pad, 0, drbg_blocklen(drbg));
 503	return ret;
 504}
 505
 506/*
 507 * update function of CTR DRBG as defined in 10.2.1.2
 508 *
 509 * The reseed variable has an enhanced meaning compared to the update
 510 * functions of the other DRBGs as follows:
 511 * 0 => initial seed from initialization
 512 * 1 => reseed via drbg_seed
 513 * 2 => first invocation from drbg_ctr_update when addtl is present. In
 514 *      this case, the df_data scratchpad is not deleted so that it is
 515 *      available for another calls to prevent calling the DF function
 516 *      again.
 517 * 3 => second invocation from drbg_ctr_update. When the update function
 518 *      was called with addtl, the df_data memory already contains the
 519 *      DFed addtl information and we do not need to call DF again.
 520 */
 521static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed,
 522			   int reseed)
 523{
 524	int ret = -EFAULT;
 525	/* 10.2.1.2 step 1 */
 526	unsigned char *temp = drbg->scratchpad;
 527	unsigned char *df_data = drbg->scratchpad + drbg_statelen(drbg) +
 528				 drbg_blocklen(drbg);
 529
 530	if (3 > reseed)
 531		memset(df_data, 0, drbg_statelen(drbg));
 532
 533	if (!reseed) {
 534		/*
 535		 * The DRBG uses the CTR mode of the underlying AES cipher. The
 536		 * CTR mode increments the counter value after the AES operation
 537		 * but SP800-90A requires that the counter is incremented before
 538		 * the AES operation. Hence, we increment it at the time we set
 539		 * it by one.
 540		 */
 541		crypto_inc(drbg->V, drbg_blocklen(drbg));
 542
 543		ret = crypto_skcipher_setkey(drbg->ctr_handle, drbg->C,
 544					     drbg_keylen(drbg));
 545		if (ret)
 546			goto out;
 547	}
 548
 549	/* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */
 550	if (seed) {
 551		ret = drbg_ctr_df(drbg, df_data, drbg_statelen(drbg), seed);
 552		if (ret)
 553			goto out;
 554	}
 555
 556	ret = drbg_kcapi_sym_ctr(drbg, df_data, drbg_statelen(drbg),
 557				 temp, drbg_statelen(drbg));
 558	if (ret)
 559		return ret;
 560
 561	/* 10.2.1.2 step 5 */
 562	ret = crypto_skcipher_setkey(drbg->ctr_handle, temp,
 563				     drbg_keylen(drbg));
 564	if (ret)
 565		goto out;
 566	/* 10.2.1.2 step 6 */
 567	memcpy(drbg->V, temp + drbg_keylen(drbg), drbg_blocklen(drbg));
 568	/* See above: increment counter by one to compensate timing of CTR op */
 569	crypto_inc(drbg->V, drbg_blocklen(drbg));
 570	ret = 0;
 571
 572out:
 573	memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
 574	if (2 != reseed)
 575		memset(df_data, 0, drbg_statelen(drbg));
 576	return ret;
 577}
 578
 579/*
 580 * scratchpad use: drbg_ctr_update is called independently from
 581 * drbg_ctr_extract_bytes. Therefore, the scratchpad is reused
 582 */
 583/* Generate function of CTR DRBG as defined in 10.2.1.5.2 */
 584static int drbg_ctr_generate(struct drbg_state *drbg,
 585			     unsigned char *buf, unsigned int buflen,
 586			     struct list_head *addtl)
 587{
 588	int ret;
 589	int len = min_t(int, buflen, INT_MAX);
 590
 591	/* 10.2.1.5.2 step 2 */
 592	if (addtl && !list_empty(addtl)) {
 593		ret = drbg_ctr_update(drbg, addtl, 2);
 594		if (ret)
 595			return 0;
 596	}
 597
 598	/* 10.2.1.5.2 step 4.1 */
 599	ret = drbg_kcapi_sym_ctr(drbg, NULL, 0, buf, len);
 600	if (ret)
 601		return ret;
 602
 603	/* 10.2.1.5.2 step 6 */
 604	ret = drbg_ctr_update(drbg, NULL, 3);
 605	if (ret)
 606		len = ret;
 607
 608	return len;
 609}
 610
 611static const struct drbg_state_ops drbg_ctr_ops = {
 612	.update		= drbg_ctr_update,
 613	.generate	= drbg_ctr_generate,
 614	.crypto_init	= drbg_init_sym_kernel,
 615	.crypto_fini	= drbg_fini_sym_kernel,
 616};
 617#endif /* CONFIG_CRYPTO_DRBG_CTR */
 618
 619/******************************************************************
 620 * HMAC DRBG callback functions
 621 ******************************************************************/
 622
 623#if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
 624static int drbg_kcapi_hash(struct drbg_state *drbg, unsigned char *outval,
 625			   const struct list_head *in);
 626static void drbg_kcapi_hmacsetkey(struct drbg_state *drbg,
 627				  const unsigned char *key);
 628static int drbg_init_hash_kernel(struct drbg_state *drbg);
 629static int drbg_fini_hash_kernel(struct drbg_state *drbg);
 630#endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
 631
 632#ifdef CONFIG_CRYPTO_DRBG_HMAC
 633#define CRYPTO_DRBG_HMAC_STRING "HMAC "
 634MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha512");
 635MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha512");
 636MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha384");
 637MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha384");
 638MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha256");
 639MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha256");
 
 
 640
 641/* update function of HMAC DRBG as defined in 10.1.2.2 */
 642static int drbg_hmac_update(struct drbg_state *drbg, struct list_head *seed,
 643			    int reseed)
 644{
 645	int ret = -EFAULT;
 646	int i = 0;
 647	struct drbg_string seed1, seed2, vdata;
 648	LIST_HEAD(seedlist);
 649	LIST_HEAD(vdatalist);
 650
 651	if (!reseed) {
 652		/* 10.1.2.3 step 2 -- memset(0) of C is implicit with kzalloc */
 653		memset(drbg->V, 1, drbg_statelen(drbg));
 654		drbg_kcapi_hmacsetkey(drbg, drbg->C);
 655	}
 656
 657	drbg_string_fill(&seed1, drbg->V, drbg_statelen(drbg));
 658	list_add_tail(&seed1.list, &seedlist);
 659	/* buffer of seed2 will be filled in for loop below with one byte */
 660	drbg_string_fill(&seed2, NULL, 1);
 661	list_add_tail(&seed2.list, &seedlist);
 662	/* input data of seed is allowed to be NULL at this point */
 663	if (seed)
 664		list_splice_tail(seed, &seedlist);
 665
 666	drbg_string_fill(&vdata, drbg->V, drbg_statelen(drbg));
 667	list_add_tail(&vdata.list, &vdatalist);
 668	for (i = 2; 0 < i; i--) {
 669		/* first round uses 0x0, second 0x1 */
 670		unsigned char prefix = DRBG_PREFIX0;
 671		if (1 == i)
 672			prefix = DRBG_PREFIX1;
 673		/* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */
 674		seed2.buf = &prefix;
 675		ret = drbg_kcapi_hash(drbg, drbg->C, &seedlist);
 676		if (ret)
 677			return ret;
 678		drbg_kcapi_hmacsetkey(drbg, drbg->C);
 679
 680		/* 10.1.2.2 step 2 and 5 -- HMAC for V */
 681		ret = drbg_kcapi_hash(drbg, drbg->V, &vdatalist);
 682		if (ret)
 683			return ret;
 684
 685		/* 10.1.2.2 step 3 */
 686		if (!seed)
 687			return ret;
 688	}
 689
 690	return 0;
 691}
 692
 693/* generate function of HMAC DRBG as defined in 10.1.2.5 */
 694static int drbg_hmac_generate(struct drbg_state *drbg,
 695			      unsigned char *buf,
 696			      unsigned int buflen,
 697			      struct list_head *addtl)
 698{
 699	int len = 0;
 700	int ret = 0;
 701	struct drbg_string data;
 702	LIST_HEAD(datalist);
 703
 704	/* 10.1.2.5 step 2 */
 705	if (addtl && !list_empty(addtl)) {
 706		ret = drbg_hmac_update(drbg, addtl, 1);
 707		if (ret)
 708			return ret;
 709	}
 710
 711	drbg_string_fill(&data, drbg->V, drbg_statelen(drbg));
 712	list_add_tail(&data.list, &datalist);
 713	while (len < buflen) {
 714		unsigned int outlen = 0;
 715		/* 10.1.2.5 step 4.1 */
 716		ret = drbg_kcapi_hash(drbg, drbg->V, &datalist);
 717		if (ret)
 718			return ret;
 719		outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
 720			  drbg_blocklen(drbg) : (buflen - len);
 721
 722		/* 10.1.2.5 step 4.2 */
 723		memcpy(buf + len, drbg->V, outlen);
 724		len += outlen;
 725	}
 726
 727	/* 10.1.2.5 step 6 */
 728	if (addtl && !list_empty(addtl))
 729		ret = drbg_hmac_update(drbg, addtl, 1);
 730	else
 731		ret = drbg_hmac_update(drbg, NULL, 1);
 732	if (ret)
 733		return ret;
 734
 735	return len;
 736}
 737
 738static const struct drbg_state_ops drbg_hmac_ops = {
 739	.update		= drbg_hmac_update,
 740	.generate	= drbg_hmac_generate,
 741	.crypto_init	= drbg_init_hash_kernel,
 742	.crypto_fini	= drbg_fini_hash_kernel,
 743};
 744#endif /* CONFIG_CRYPTO_DRBG_HMAC */
 745
 746/******************************************************************
 747 * Hash DRBG callback functions
 748 ******************************************************************/
 749
 750#ifdef CONFIG_CRYPTO_DRBG_HASH
 751#define CRYPTO_DRBG_HASH_STRING "HASH "
 752MODULE_ALIAS_CRYPTO("drbg_pr_sha512");
 753MODULE_ALIAS_CRYPTO("drbg_nopr_sha512");
 754MODULE_ALIAS_CRYPTO("drbg_pr_sha384");
 755MODULE_ALIAS_CRYPTO("drbg_nopr_sha384");
 756MODULE_ALIAS_CRYPTO("drbg_pr_sha256");
 757MODULE_ALIAS_CRYPTO("drbg_nopr_sha256");
 
 
 758
 759/*
 760 * Increment buffer
 761 *
 762 * @dst buffer to increment
 763 * @add value to add
 764 */
 765static inline void drbg_add_buf(unsigned char *dst, size_t dstlen,
 766				const unsigned char *add, size_t addlen)
 767{
 768	/* implied: dstlen > addlen */
 769	unsigned char *dstptr;
 770	const unsigned char *addptr;
 771	unsigned int remainder = 0;
 772	size_t len = addlen;
 773
 774	dstptr = dst + (dstlen-1);
 775	addptr = add + (addlen-1);
 776	while (len) {
 777		remainder += *dstptr + *addptr;
 778		*dstptr = remainder & 0xff;
 779		remainder >>= 8;
 780		len--; dstptr--; addptr--;
 781	}
 782	len = dstlen - addlen;
 783	while (len && remainder > 0) {
 784		remainder = *dstptr + 1;
 785		*dstptr = remainder & 0xff;
 786		remainder >>= 8;
 787		len--; dstptr--;
 788	}
 789}
 790
 791/*
 792 * scratchpad usage: as drbg_hash_update and drbg_hash_df are used
 793 * interlinked, the scratchpad is used as follows:
 794 * drbg_hash_update
 795 *	start: drbg->scratchpad
 796 *	length: drbg_statelen(drbg)
 797 * drbg_hash_df:
 798 *	start: drbg->scratchpad + drbg_statelen(drbg)
 799 *	length: drbg_blocklen(drbg)
 800 *
 801 * drbg_hash_process_addtl uses the scratchpad, but fully completes
 802 * before either of the functions mentioned before are invoked. Therefore,
 803 * drbg_hash_process_addtl does not need to be specifically considered.
 804 */
 805
 806/* Derivation Function for Hash DRBG as defined in 10.4.1 */
 807static int drbg_hash_df(struct drbg_state *drbg,
 808			unsigned char *outval, size_t outlen,
 809			struct list_head *entropylist)
 810{
 811	int ret = 0;
 812	size_t len = 0;
 813	unsigned char input[5];
 814	unsigned char *tmp = drbg->scratchpad + drbg_statelen(drbg);
 815	struct drbg_string data;
 816
 817	/* 10.4.1 step 3 */
 818	input[0] = 1;
 819	drbg_cpu_to_be32((outlen * 8), &input[1]);
 820
 821	/* 10.4.1 step 4.1 -- concatenation of data for input into hash */
 822	drbg_string_fill(&data, input, 5);
 823	list_add(&data.list, entropylist);
 824
 825	/* 10.4.1 step 4 */
 826	while (len < outlen) {
 827		short blocklen = 0;
 828		/* 10.4.1 step 4.1 */
 829		ret = drbg_kcapi_hash(drbg, tmp, entropylist);
 830		if (ret)
 831			goto out;
 832		/* 10.4.1 step 4.2 */
 833		input[0]++;
 834		blocklen = (drbg_blocklen(drbg) < (outlen - len)) ?
 835			    drbg_blocklen(drbg) : (outlen - len);
 836		memcpy(outval + len, tmp, blocklen);
 837		len += blocklen;
 838	}
 839
 840out:
 841	memset(tmp, 0, drbg_blocklen(drbg));
 842	return ret;
 843}
 844
 845/* update function for Hash DRBG as defined in 10.1.1.2 / 10.1.1.3 */
 846static int drbg_hash_update(struct drbg_state *drbg, struct list_head *seed,
 847			    int reseed)
 848{
 849	int ret = 0;
 850	struct drbg_string data1, data2;
 851	LIST_HEAD(datalist);
 852	LIST_HEAD(datalist2);
 853	unsigned char *V = drbg->scratchpad;
 854	unsigned char prefix = DRBG_PREFIX1;
 855
 856	if (!seed)
 857		return -EINVAL;
 858
 859	if (reseed) {
 860		/* 10.1.1.3 step 1 */
 861		memcpy(V, drbg->V, drbg_statelen(drbg));
 862		drbg_string_fill(&data1, &prefix, 1);
 863		list_add_tail(&data1.list, &datalist);
 864		drbg_string_fill(&data2, V, drbg_statelen(drbg));
 865		list_add_tail(&data2.list, &datalist);
 866	}
 867	list_splice_tail(seed, &datalist);
 868
 869	/* 10.1.1.2 / 10.1.1.3 step 2 and 3 */
 870	ret = drbg_hash_df(drbg, drbg->V, drbg_statelen(drbg), &datalist);
 871	if (ret)
 872		goto out;
 873
 874	/* 10.1.1.2 / 10.1.1.3 step 4  */
 875	prefix = DRBG_PREFIX0;
 876	drbg_string_fill(&data1, &prefix, 1);
 877	list_add_tail(&data1.list, &datalist2);
 878	drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
 879	list_add_tail(&data2.list, &datalist2);
 880	/* 10.1.1.2 / 10.1.1.3 step 4 */
 881	ret = drbg_hash_df(drbg, drbg->C, drbg_statelen(drbg), &datalist2);
 882
 883out:
 884	memset(drbg->scratchpad, 0, drbg_statelen(drbg));
 885	return ret;
 886}
 887
 888/* processing of additional information string for Hash DRBG */
 889static int drbg_hash_process_addtl(struct drbg_state *drbg,
 890				   struct list_head *addtl)
 891{
 892	int ret = 0;
 893	struct drbg_string data1, data2;
 894	LIST_HEAD(datalist);
 895	unsigned char prefix = DRBG_PREFIX2;
 896
 897	/* 10.1.1.4 step 2 */
 898	if (!addtl || list_empty(addtl))
 899		return 0;
 900
 901	/* 10.1.1.4 step 2a */
 902	drbg_string_fill(&data1, &prefix, 1);
 903	drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
 904	list_add_tail(&data1.list, &datalist);
 905	list_add_tail(&data2.list, &datalist);
 906	list_splice_tail(addtl, &datalist);
 907	ret = drbg_kcapi_hash(drbg, drbg->scratchpad, &datalist);
 908	if (ret)
 909		goto out;
 910
 911	/* 10.1.1.4 step 2b */
 912	drbg_add_buf(drbg->V, drbg_statelen(drbg),
 913		     drbg->scratchpad, drbg_blocklen(drbg));
 914
 915out:
 916	memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
 917	return ret;
 918}
 919
 920/* Hashgen defined in 10.1.1.4 */
 921static int drbg_hash_hashgen(struct drbg_state *drbg,
 922			     unsigned char *buf,
 923			     unsigned int buflen)
 924{
 925	int len = 0;
 926	int ret = 0;
 927	unsigned char *src = drbg->scratchpad;
 928	unsigned char *dst = drbg->scratchpad + drbg_statelen(drbg);
 929	struct drbg_string data;
 930	LIST_HEAD(datalist);
 931
 932	/* 10.1.1.4 step hashgen 2 */
 933	memcpy(src, drbg->V, drbg_statelen(drbg));
 934
 935	drbg_string_fill(&data, src, drbg_statelen(drbg));
 936	list_add_tail(&data.list, &datalist);
 937	while (len < buflen) {
 938		unsigned int outlen = 0;
 939		/* 10.1.1.4 step hashgen 4.1 */
 940		ret = drbg_kcapi_hash(drbg, dst, &datalist);
 941		if (ret) {
 942			len = ret;
 943			goto out;
 944		}
 945		outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
 946			  drbg_blocklen(drbg) : (buflen - len);
 947		/* 10.1.1.4 step hashgen 4.2 */
 948		memcpy(buf + len, dst, outlen);
 949		len += outlen;
 950		/* 10.1.1.4 hashgen step 4.3 */
 951		if (len < buflen)
 952			crypto_inc(src, drbg_statelen(drbg));
 953	}
 954
 955out:
 956	memset(drbg->scratchpad, 0,
 957	       (drbg_statelen(drbg) + drbg_blocklen(drbg)));
 958	return len;
 959}
 960
 961/* generate function for Hash DRBG as defined in  10.1.1.4 */
 962static int drbg_hash_generate(struct drbg_state *drbg,
 963			      unsigned char *buf, unsigned int buflen,
 964			      struct list_head *addtl)
 965{
 966	int len = 0;
 967	int ret = 0;
 968	union {
 969		unsigned char req[8];
 970		__be64 req_int;
 971	} u;
 972	unsigned char prefix = DRBG_PREFIX3;
 973	struct drbg_string data1, data2;
 974	LIST_HEAD(datalist);
 975
 976	/* 10.1.1.4 step 2 */
 977	ret = drbg_hash_process_addtl(drbg, addtl);
 978	if (ret)
 979		return ret;
 980	/* 10.1.1.4 step 3 */
 981	len = drbg_hash_hashgen(drbg, buf, buflen);
 982
 983	/* this is the value H as documented in 10.1.1.4 */
 984	/* 10.1.1.4 step 4 */
 985	drbg_string_fill(&data1, &prefix, 1);
 986	list_add_tail(&data1.list, &datalist);
 987	drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
 988	list_add_tail(&data2.list, &datalist);
 989	ret = drbg_kcapi_hash(drbg, drbg->scratchpad, &datalist);
 990	if (ret) {
 991		len = ret;
 992		goto out;
 993	}
 994
 995	/* 10.1.1.4 step 5 */
 996	drbg_add_buf(drbg->V, drbg_statelen(drbg),
 997		     drbg->scratchpad, drbg_blocklen(drbg));
 998	drbg_add_buf(drbg->V, drbg_statelen(drbg),
 999		     drbg->C, drbg_statelen(drbg));
1000	u.req_int = cpu_to_be64(drbg->reseed_ctr);
1001	drbg_add_buf(drbg->V, drbg_statelen(drbg), u.req, 8);
1002
1003out:
1004	memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
1005	return len;
1006}
1007
1008/*
1009 * scratchpad usage: as update and generate are used isolated, both
1010 * can use the scratchpad
1011 */
1012static const struct drbg_state_ops drbg_hash_ops = {
1013	.update		= drbg_hash_update,
1014	.generate	= drbg_hash_generate,
1015	.crypto_init	= drbg_init_hash_kernel,
1016	.crypto_fini	= drbg_fini_hash_kernel,
1017};
1018#endif /* CONFIG_CRYPTO_DRBG_HASH */
1019
1020/******************************************************************
1021 * Functions common for DRBG implementations
1022 ******************************************************************/
1023
1024static inline int __drbg_seed(struct drbg_state *drbg, struct list_head *seed,
1025			      int reseed, enum drbg_seed_state new_seed_state)
1026{
1027	int ret = drbg->d_ops->update(drbg, seed, reseed);
1028
1029	if (ret)
1030		return ret;
1031
1032	drbg->seeded = new_seed_state;
1033	drbg->last_seed_time = jiffies;
1034	/* 10.1.1.2 / 10.1.1.3 step 5 */
1035	drbg->reseed_ctr = 1;
1036
1037	switch (drbg->seeded) {
1038	case DRBG_SEED_STATE_UNSEEDED:
1039		/* Impossible, but handle it to silence compiler warnings. */
1040		fallthrough;
1041	case DRBG_SEED_STATE_PARTIAL:
1042		/*
1043		 * Require frequent reseeds until the seed source is
1044		 * fully initialized.
1045		 */
1046		drbg->reseed_threshold = 50;
1047		break;
1048
1049	case DRBG_SEED_STATE_FULL:
1050		/*
1051		 * Seed source has become fully initialized, frequent
1052		 * reseeds no longer required.
1053		 */
1054		drbg->reseed_threshold = drbg_max_requests(drbg);
1055		break;
1056	}
1057
1058	return ret;
1059}
1060
1061static inline int drbg_get_random_bytes(struct drbg_state *drbg,
1062					unsigned char *entropy,
1063					unsigned int entropylen)
1064{
1065	int ret;
1066
1067	do {
1068		get_random_bytes(entropy, entropylen);
1069		ret = drbg_fips_continuous_test(drbg, entropy);
1070		if (ret && ret != -EAGAIN)
1071			return ret;
1072	} while (ret);
1073
1074	return 0;
1075}
1076
1077static int drbg_seed_from_random(struct drbg_state *drbg)
1078{
1079	struct drbg_string data;
1080	LIST_HEAD(seedlist);
 
 
1081	unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
1082	unsigned char entropy[32];
1083	int ret;
1084
1085	BUG_ON(!entropylen);
1086	BUG_ON(entropylen > sizeof(entropy));
1087
1088	drbg_string_fill(&data, entropy, entropylen);
1089	list_add_tail(&data.list, &seedlist);
1090
 
 
1091	ret = drbg_get_random_bytes(drbg, entropy, entropylen);
1092	if (ret)
1093		goto out;
1094
1095	ret = __drbg_seed(drbg, &seedlist, true, DRBG_SEED_STATE_FULL);
 
 
 
1096
1097out:
1098	memzero_explicit(entropy, entropylen);
1099	return ret;
1100}
1101
1102static bool drbg_nopr_reseed_interval_elapsed(struct drbg_state *drbg)
1103{
1104	unsigned long next_reseed;
1105
1106	/* Don't ever reseed from get_random_bytes() in test mode. */
1107	if (list_empty(&drbg->test_data.list))
1108		return false;
1109
1110	/*
1111	 * Obtain fresh entropy for the nopr DRBGs after 300s have
1112	 * elapsed in order to still achieve sort of partial
1113	 * prediction resistance over the time domain at least. Note
1114	 * that the period of 300s has been chosen to match the
1115	 * CRNG_RESEED_INTERVAL of the get_random_bytes()' chacha
1116	 * rngs.
1117	 */
1118	next_reseed = drbg->last_seed_time + 300 * HZ;
1119	return time_after(jiffies, next_reseed);
1120}
1121
1122/*
1123 * Seeding or reseeding of the DRBG
1124 *
1125 * @drbg: DRBG state struct
1126 * @pers: personalization / additional information buffer
1127 * @reseed: 0 for initial seed process, 1 for reseeding
1128 *
1129 * return:
1130 *	0 on success
1131 *	error value otherwise
1132 */
1133static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
1134		     bool reseed)
1135{
1136	int ret;
1137	unsigned char entropy[((32 + 16) * 2)];
1138	unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
1139	struct drbg_string data1;
1140	LIST_HEAD(seedlist);
1141	enum drbg_seed_state new_seed_state = DRBG_SEED_STATE_FULL;
1142
1143	/* 9.1 / 9.2 / 9.3.1 step 3 */
1144	if (pers && pers->len > (drbg_max_addtl(drbg))) {
1145		pr_devel("DRBG: personalization string too long %zu\n",
1146			 pers->len);
1147		return -EINVAL;
1148	}
1149
1150	if (list_empty(&drbg->test_data.list)) {
1151		drbg_string_fill(&data1, drbg->test_data.buf,
1152				 drbg->test_data.len);
1153		pr_devel("DRBG: using test entropy\n");
1154	} else {
1155		/*
1156		 * Gather entropy equal to the security strength of the DRBG.
1157		 * With a derivation function, a nonce is required in addition
1158		 * to the entropy. A nonce must be at least 1/2 of the security
1159		 * strength of the DRBG in size. Thus, entropy + nonce is 3/2
1160		 * of the strength. The consideration of a nonce is only
1161		 * applicable during initial seeding.
1162		 */
1163		BUG_ON(!entropylen);
1164		if (!reseed)
1165			entropylen = ((entropylen + 1) / 2) * 3;
1166		BUG_ON((entropylen * 2) > sizeof(entropy));
1167
1168		/* Get seed from in-kernel /dev/urandom */
1169		if (!rng_is_initialized())
1170			new_seed_state = DRBG_SEED_STATE_PARTIAL;
1171
1172		ret = drbg_get_random_bytes(drbg, entropy, entropylen);
1173		if (ret)
1174			goto out;
1175
1176		if (!drbg->jent) {
1177			drbg_string_fill(&data1, entropy, entropylen);
1178			pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
1179				 entropylen);
1180		} else {
1181			/*
1182			 * Get seed from Jitter RNG, failures are
1183			 * fatal only in FIPS mode.
1184			 */
1185			ret = crypto_rng_get_bytes(drbg->jent,
1186						   entropy + entropylen,
1187						   entropylen);
1188			if (fips_enabled && ret) {
1189				pr_devel("DRBG: jent failed with %d\n", ret);
1190
1191				/*
1192				 * Do not treat the transient failure of the
1193				 * Jitter RNG as an error that needs to be
1194				 * reported. The combined number of the
1195				 * maximum reseed threshold times the maximum
1196				 * number of Jitter RNG transient errors is
1197				 * less than the reseed threshold required by
1198				 * SP800-90A allowing us to treat the
1199				 * transient errors as such.
1200				 *
1201				 * However, we mandate that at least the first
1202				 * seeding operation must succeed with the
1203				 * Jitter RNG.
1204				 */
1205				if (!reseed || ret != -EAGAIN)
1206					goto out;
1207			}
1208
1209			drbg_string_fill(&data1, entropy, entropylen * 2);
1210			pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
1211				 entropylen * 2);
1212		}
1213	}
1214	list_add_tail(&data1.list, &seedlist);
1215
1216	/*
1217	 * concatenation of entropy with personalization str / addtl input)
1218	 * the variable pers is directly handed in by the caller, so check its
1219	 * contents whether it is appropriate
1220	 */
1221	if (pers && pers->buf && 0 < pers->len) {
1222		list_add_tail(&pers->list, &seedlist);
1223		pr_devel("DRBG: using personalization string\n");
1224	}
1225
1226	if (!reseed) {
1227		memset(drbg->V, 0, drbg_statelen(drbg));
1228		memset(drbg->C, 0, drbg_statelen(drbg));
1229	}
1230
1231	ret = __drbg_seed(drbg, &seedlist, reseed, new_seed_state);
1232
1233out:
1234	memzero_explicit(entropy, entropylen * 2);
1235
1236	return ret;
1237}
1238
1239/* Free all substructures in a DRBG state without the DRBG state structure */
1240static inline void drbg_dealloc_state(struct drbg_state *drbg)
1241{
1242	if (!drbg)
1243		return;
1244	kfree_sensitive(drbg->Vbuf);
1245	drbg->Vbuf = NULL;
1246	drbg->V = NULL;
1247	kfree_sensitive(drbg->Cbuf);
1248	drbg->Cbuf = NULL;
1249	drbg->C = NULL;
1250	kfree_sensitive(drbg->scratchpadbuf);
1251	drbg->scratchpadbuf = NULL;
1252	drbg->reseed_ctr = 0;
1253	drbg->d_ops = NULL;
1254	drbg->core = NULL;
1255	if (IS_ENABLED(CONFIG_CRYPTO_FIPS)) {
1256		kfree_sensitive(drbg->prev);
1257		drbg->prev = NULL;
1258		drbg->fips_primed = false;
1259	}
1260}
1261
1262/*
1263 * Allocate all sub-structures for a DRBG state.
1264 * The DRBG state structure must already be allocated.
1265 */
1266static inline int drbg_alloc_state(struct drbg_state *drbg)
1267{
1268	int ret = -ENOMEM;
1269	unsigned int sb_size = 0;
1270
1271	switch (drbg->core->flags & DRBG_TYPE_MASK) {
1272#ifdef CONFIG_CRYPTO_DRBG_HMAC
1273	case DRBG_HMAC:
1274		drbg->d_ops = &drbg_hmac_ops;
1275		break;
1276#endif /* CONFIG_CRYPTO_DRBG_HMAC */
1277#ifdef CONFIG_CRYPTO_DRBG_HASH
1278	case DRBG_HASH:
1279		drbg->d_ops = &drbg_hash_ops;
1280		break;
1281#endif /* CONFIG_CRYPTO_DRBG_HASH */
1282#ifdef CONFIG_CRYPTO_DRBG_CTR
1283	case DRBG_CTR:
1284		drbg->d_ops = &drbg_ctr_ops;
1285		break;
1286#endif /* CONFIG_CRYPTO_DRBG_CTR */
1287	default:
1288		ret = -EOPNOTSUPP;
1289		goto err;
1290	}
1291
1292	ret = drbg->d_ops->crypto_init(drbg);
1293	if (ret < 0)
1294		goto err;
1295
1296	drbg->Vbuf = kmalloc(drbg_statelen(drbg) + ret, GFP_KERNEL);
1297	if (!drbg->Vbuf) {
1298		ret = -ENOMEM;
1299		goto fini;
1300	}
1301	drbg->V = PTR_ALIGN(drbg->Vbuf, ret + 1);
1302	drbg->Cbuf = kmalloc(drbg_statelen(drbg) + ret, GFP_KERNEL);
1303	if (!drbg->Cbuf) {
1304		ret = -ENOMEM;
1305		goto fini;
1306	}
1307	drbg->C = PTR_ALIGN(drbg->Cbuf, ret + 1);
1308	/* scratchpad is only generated for CTR and Hash */
1309	if (drbg->core->flags & DRBG_HMAC)
1310		sb_size = 0;
1311	else if (drbg->core->flags & DRBG_CTR)
1312		sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg) + /* temp */
1313			  drbg_statelen(drbg) +	/* df_data */
1314			  drbg_blocklen(drbg) +	/* pad */
1315			  drbg_blocklen(drbg) +	/* iv */
1316			  drbg_statelen(drbg) + drbg_blocklen(drbg); /* temp */
1317	else
1318		sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg);
1319
1320	if (0 < sb_size) {
1321		drbg->scratchpadbuf = kzalloc(sb_size + ret, GFP_KERNEL);
1322		if (!drbg->scratchpadbuf) {
1323			ret = -ENOMEM;
1324			goto fini;
1325		}
1326		drbg->scratchpad = PTR_ALIGN(drbg->scratchpadbuf, ret + 1);
1327	}
1328
1329	if (IS_ENABLED(CONFIG_CRYPTO_FIPS)) {
1330		drbg->prev = kzalloc(drbg_sec_strength(drbg->core->flags),
1331				     GFP_KERNEL);
1332		if (!drbg->prev) {
1333			ret = -ENOMEM;
1334			goto fini;
1335		}
1336		drbg->fips_primed = false;
1337	}
1338
1339	return 0;
1340
1341fini:
1342	drbg->d_ops->crypto_fini(drbg);
1343err:
1344	drbg_dealloc_state(drbg);
1345	return ret;
1346}
1347
1348/*************************************************************************
1349 * DRBG interface functions
1350 *************************************************************************/
1351
1352/*
1353 * DRBG generate function as required by SP800-90A - this function
1354 * generates random numbers
1355 *
1356 * @drbg DRBG state handle
1357 * @buf Buffer where to store the random numbers -- the buffer must already
1358 *      be pre-allocated by caller
1359 * @buflen Length of output buffer - this value defines the number of random
1360 *	   bytes pulled from DRBG
1361 * @addtl Additional input that is mixed into state, may be NULL -- note
1362 *	  the entropy is pulled by the DRBG internally unconditionally
1363 *	  as defined in SP800-90A. The additional input is mixed into
1364 *	  the state in addition to the pulled entropy.
1365 *
1366 * return: 0 when all bytes are generated; < 0 in case of an error
1367 */
1368static int drbg_generate(struct drbg_state *drbg,
1369			 unsigned char *buf, unsigned int buflen,
1370			 struct drbg_string *addtl)
1371{
1372	int len = 0;
1373	LIST_HEAD(addtllist);
1374
1375	if (!drbg->core) {
1376		pr_devel("DRBG: not yet seeded\n");
1377		return -EINVAL;
1378	}
1379	if (0 == buflen || !buf) {
1380		pr_devel("DRBG: no output buffer provided\n");
1381		return -EINVAL;
1382	}
1383	if (addtl && NULL == addtl->buf && 0 < addtl->len) {
1384		pr_devel("DRBG: wrong format of additional information\n");
1385		return -EINVAL;
1386	}
1387
1388	/* 9.3.1 step 2 */
1389	len = -EINVAL;
1390	if (buflen > (drbg_max_request_bytes(drbg))) {
1391		pr_devel("DRBG: requested random numbers too large %u\n",
1392			 buflen);
1393		goto err;
1394	}
1395
1396	/* 9.3.1 step 3 is implicit with the chosen DRBG */
1397
1398	/* 9.3.1 step 4 */
1399	if (addtl && addtl->len > (drbg_max_addtl(drbg))) {
1400		pr_devel("DRBG: additional information string too long %zu\n",
1401			 addtl->len);
1402		goto err;
1403	}
1404	/* 9.3.1 step 5 is implicit with the chosen DRBG */
1405
1406	/*
1407	 * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented
1408	 * here. The spec is a bit convoluted here, we make it simpler.
1409	 */
1410	if (drbg->reseed_threshold < drbg->reseed_ctr)
1411		drbg->seeded = DRBG_SEED_STATE_UNSEEDED;
1412
1413	if (drbg->pr || drbg->seeded == DRBG_SEED_STATE_UNSEEDED) {
1414		pr_devel("DRBG: reseeding before generation (prediction "
1415			 "resistance: %s, state %s)\n",
1416			 str_true_false(drbg->pr),
1417			 (drbg->seeded ==  DRBG_SEED_STATE_FULL ?
1418			  "seeded" : "unseeded"));
1419		/* 9.3.1 steps 7.1 through 7.3 */
1420		len = drbg_seed(drbg, addtl, true);
1421		if (len)
1422			goto err;
1423		/* 9.3.1 step 7.4 */
1424		addtl = NULL;
1425	} else if (rng_is_initialized() &&
1426		   (drbg->seeded == DRBG_SEED_STATE_PARTIAL ||
1427		    drbg_nopr_reseed_interval_elapsed(drbg))) {
1428		len = drbg_seed_from_random(drbg);
1429		if (len)
1430			goto err;
1431	}
1432
1433	if (addtl && 0 < addtl->len)
1434		list_add_tail(&addtl->list, &addtllist);
1435	/* 9.3.1 step 8 and 10 */
1436	len = drbg->d_ops->generate(drbg, buf, buflen, &addtllist);
1437
1438	/* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */
1439	drbg->reseed_ctr++;
1440	if (0 >= len)
1441		goto err;
1442
1443	/*
1444	 * Section 11.3.3 requires to re-perform self tests after some
1445	 * generated random numbers. The chosen value after which self
1446	 * test is performed is arbitrary, but it should be reasonable.
1447	 * However, we do not perform the self tests because of the following
1448	 * reasons: it is mathematically impossible that the initial self tests
1449	 * were successfully and the following are not. If the initial would
1450	 * pass and the following would not, the kernel integrity is violated.
1451	 * In this case, the entire kernel operation is questionable and it
1452	 * is unlikely that the integrity violation only affects the
1453	 * correct operation of the DRBG.
1454	 *
1455	 * Albeit the following code is commented out, it is provided in
1456	 * case somebody has a need to implement the test of 11.3.3.
1457	 */
1458#if 0
1459	if (drbg->reseed_ctr && !(drbg->reseed_ctr % 4096)) {
1460		int err = 0;
1461		pr_devel("DRBG: start to perform self test\n");
1462		if (drbg->core->flags & DRBG_HMAC)
1463			err = alg_test("drbg_pr_hmac_sha512",
1464				       "drbg_pr_hmac_sha512", 0, 0);
1465		else if (drbg->core->flags & DRBG_CTR)
1466			err = alg_test("drbg_pr_ctr_aes256",
1467				       "drbg_pr_ctr_aes256", 0, 0);
1468		else
1469			err = alg_test("drbg_pr_sha256",
1470				       "drbg_pr_sha256", 0, 0);
1471		if (err) {
1472			pr_err("DRBG: periodical self test failed\n");
1473			/*
1474			 * uninstantiate implies that from now on, only errors
1475			 * are returned when reusing this DRBG cipher handle
1476			 */
1477			drbg_uninstantiate(drbg);
1478			return 0;
1479		} else {
1480			pr_devel("DRBG: self test successful\n");
1481		}
1482	}
1483#endif
1484
1485	/*
1486	 * All operations were successful, return 0 as mandated by
1487	 * the kernel crypto API interface.
1488	 */
1489	len = 0;
1490err:
1491	return len;
1492}
1493
1494/*
1495 * Wrapper around drbg_generate which can pull arbitrary long strings
1496 * from the DRBG without hitting the maximum request limitation.
1497 *
1498 * Parameters: see drbg_generate
1499 * Return codes: see drbg_generate -- if one drbg_generate request fails,
1500 *		 the entire drbg_generate_long request fails
1501 */
1502static int drbg_generate_long(struct drbg_state *drbg,
1503			      unsigned char *buf, unsigned int buflen,
1504			      struct drbg_string *addtl)
1505{
1506	unsigned int len = 0;
1507	unsigned int slice = 0;
1508	do {
1509		int err = 0;
1510		unsigned int chunk = 0;
1511		slice = ((buflen - len) / drbg_max_request_bytes(drbg));
1512		chunk = slice ? drbg_max_request_bytes(drbg) : (buflen - len);
1513		mutex_lock(&drbg->drbg_mutex);
1514		err = drbg_generate(drbg, buf + len, chunk, addtl);
1515		mutex_unlock(&drbg->drbg_mutex);
1516		if (0 > err)
1517			return err;
1518		len += chunk;
1519	} while (slice > 0 && (len < buflen));
1520	return 0;
1521}
1522
 
 
 
 
 
 
 
 
1523static int drbg_prepare_hrng(struct drbg_state *drbg)
1524{
 
 
1525	/* We do not need an HRNG in test mode. */
1526	if (list_empty(&drbg->test_data.list))
1527		return 0;
1528
1529	drbg->jent = crypto_alloc_rng("jitterentropy_rng", 0, 0);
1530	if (IS_ERR(drbg->jent)) {
1531		const int err = PTR_ERR(drbg->jent);
1532
1533		drbg->jent = NULL;
1534		if (fips_enabled)
1535			return err;
1536		pr_info("DRBG: Continuing without Jitter RNG\n");
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1537	}
1538
1539	return 0;
 
 
 
 
 
 
1540}
1541
1542/*
1543 * DRBG instantiation function as required by SP800-90A - this function
1544 * sets up the DRBG handle, performs the initial seeding and all sanity
1545 * checks required by SP800-90A
1546 *
1547 * @drbg memory of state -- if NULL, new memory is allocated
1548 * @pers Personalization string that is mixed into state, may be NULL -- note
1549 *	 the entropy is pulled by the DRBG internally unconditionally
1550 *	 as defined in SP800-90A. The additional input is mixed into
1551 *	 the state in addition to the pulled entropy.
1552 * @coreref reference to core
1553 * @pr prediction resistance enabled
1554 *
1555 * return
1556 *	0 on success
1557 *	error value otherwise
1558 */
1559static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers,
1560			    int coreref, bool pr)
1561{
1562	int ret;
1563	bool reseed = true;
1564
1565	pr_devel("DRBG: Initializing DRBG core %d with prediction resistance "
1566		 "%s\n", coreref, str_enabled_disabled(pr));
1567	mutex_lock(&drbg->drbg_mutex);
1568
1569	/* 9.1 step 1 is implicit with the selected DRBG type */
1570
1571	/*
1572	 * 9.1 step 2 is implicit as caller can select prediction resistance
1573	 * and the flag is copied into drbg->flags --
1574	 * all DRBG types support prediction resistance
1575	 */
1576
1577	/* 9.1 step 4 is implicit in  drbg_sec_strength */
1578
1579	if (!drbg->core) {
1580		drbg->core = &drbg_cores[coreref];
1581		drbg->pr = pr;
1582		drbg->seeded = DRBG_SEED_STATE_UNSEEDED;
1583		drbg->last_seed_time = 0;
1584		drbg->reseed_threshold = drbg_max_requests(drbg);
1585
1586		ret = drbg_alloc_state(drbg);
1587		if (ret)
1588			goto unlock;
1589
1590		ret = drbg_prepare_hrng(drbg);
1591		if (ret)
1592			goto free_everything;
1593
 
 
 
 
 
 
 
 
1594		reseed = false;
1595	}
1596
1597	ret = drbg_seed(drbg, pers, reseed);
1598
1599	if (ret && !reseed)
1600		goto free_everything;
1601
1602	mutex_unlock(&drbg->drbg_mutex);
1603	return ret;
1604
1605unlock:
1606	mutex_unlock(&drbg->drbg_mutex);
1607	return ret;
1608
1609free_everything:
1610	mutex_unlock(&drbg->drbg_mutex);
1611	drbg_uninstantiate(drbg);
1612	return ret;
1613}
1614
1615/*
1616 * DRBG uninstantiate function as required by SP800-90A - this function
1617 * frees all buffers and the DRBG handle
1618 *
1619 * @drbg DRBG state handle
1620 *
1621 * return
1622 *	0 on success
1623 */
1624static int drbg_uninstantiate(struct drbg_state *drbg)
1625{
 
 
 
 
 
1626	if (!IS_ERR_OR_NULL(drbg->jent))
1627		crypto_free_rng(drbg->jent);
1628	drbg->jent = NULL;
1629
1630	if (drbg->d_ops)
1631		drbg->d_ops->crypto_fini(drbg);
1632	drbg_dealloc_state(drbg);
1633	/* no scrubbing of test_data -- this shall survive an uninstantiate */
1634	return 0;
1635}
1636
1637/*
1638 * Helper function for setting the test data in the DRBG
1639 *
1640 * @drbg DRBG state handle
1641 * @data test data
1642 * @len test data length
1643 */
1644static void drbg_kcapi_set_entropy(struct crypto_rng *tfm,
1645				   const u8 *data, unsigned int len)
1646{
1647	struct drbg_state *drbg = crypto_rng_ctx(tfm);
1648
1649	mutex_lock(&drbg->drbg_mutex);
1650	drbg_string_fill(&drbg->test_data, data, len);
1651	mutex_unlock(&drbg->drbg_mutex);
1652}
1653
1654/***************************************************************
1655 * Kernel crypto API cipher invocations requested by DRBG
1656 ***************************************************************/
1657
1658#if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
1659struct sdesc {
1660	struct shash_desc shash;
1661	char ctx[];
1662};
1663
1664static int drbg_init_hash_kernel(struct drbg_state *drbg)
1665{
1666	struct sdesc *sdesc;
1667	struct crypto_shash *tfm;
1668
1669	tfm = crypto_alloc_shash(drbg->core->backend_cra_name, 0, 0);
1670	if (IS_ERR(tfm)) {
1671		pr_info("DRBG: could not allocate digest TFM handle: %s\n",
1672				drbg->core->backend_cra_name);
1673		return PTR_ERR(tfm);
1674	}
1675	BUG_ON(drbg_blocklen(drbg) != crypto_shash_digestsize(tfm));
1676	sdesc = kzalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm),
1677			GFP_KERNEL);
1678	if (!sdesc) {
1679		crypto_free_shash(tfm);
1680		return -ENOMEM;
1681	}
1682
1683	sdesc->shash.tfm = tfm;
1684	drbg->priv_data = sdesc;
1685
1686	return 0;
1687}
1688
1689static int drbg_fini_hash_kernel(struct drbg_state *drbg)
1690{
1691	struct sdesc *sdesc = drbg->priv_data;
1692	if (sdesc) {
1693		crypto_free_shash(sdesc->shash.tfm);
1694		kfree_sensitive(sdesc);
1695	}
1696	drbg->priv_data = NULL;
1697	return 0;
1698}
1699
1700static void drbg_kcapi_hmacsetkey(struct drbg_state *drbg,
1701				  const unsigned char *key)
1702{
1703	struct sdesc *sdesc = drbg->priv_data;
1704
1705	crypto_shash_setkey(sdesc->shash.tfm, key, drbg_statelen(drbg));
1706}
1707
1708static int drbg_kcapi_hash(struct drbg_state *drbg, unsigned char *outval,
1709			   const struct list_head *in)
1710{
1711	struct sdesc *sdesc = drbg->priv_data;
1712	struct drbg_string *input = NULL;
1713
1714	crypto_shash_init(&sdesc->shash);
1715	list_for_each_entry(input, in, list)
1716		crypto_shash_update(&sdesc->shash, input->buf, input->len);
1717	return crypto_shash_final(&sdesc->shash, outval);
1718}
1719#endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
1720
1721#ifdef CONFIG_CRYPTO_DRBG_CTR
1722static int drbg_fini_sym_kernel(struct drbg_state *drbg)
1723{
1724	struct crypto_cipher *tfm =
1725		(struct crypto_cipher *)drbg->priv_data;
1726	if (tfm)
1727		crypto_free_cipher(tfm);
1728	drbg->priv_data = NULL;
1729
1730	if (drbg->ctr_handle)
1731		crypto_free_skcipher(drbg->ctr_handle);
1732	drbg->ctr_handle = NULL;
1733
1734	if (drbg->ctr_req)
1735		skcipher_request_free(drbg->ctr_req);
1736	drbg->ctr_req = NULL;
1737
1738	kfree(drbg->outscratchpadbuf);
1739	drbg->outscratchpadbuf = NULL;
1740
1741	return 0;
1742}
1743
1744static int drbg_init_sym_kernel(struct drbg_state *drbg)
1745{
1746	struct crypto_cipher *tfm;
1747	struct crypto_skcipher *sk_tfm;
1748	struct skcipher_request *req;
1749	unsigned int alignmask;
1750	char ctr_name[CRYPTO_MAX_ALG_NAME];
1751
1752	tfm = crypto_alloc_cipher(drbg->core->backend_cra_name, 0, 0);
1753	if (IS_ERR(tfm)) {
1754		pr_info("DRBG: could not allocate cipher TFM handle: %s\n",
1755				drbg->core->backend_cra_name);
1756		return PTR_ERR(tfm);
1757	}
1758	BUG_ON(drbg_blocklen(drbg) != crypto_cipher_blocksize(tfm));
1759	drbg->priv_data = tfm;
1760
1761	if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)",
1762	    drbg->core->backend_cra_name) >= CRYPTO_MAX_ALG_NAME) {
1763		drbg_fini_sym_kernel(drbg);
1764		return -EINVAL;
1765	}
1766	sk_tfm = crypto_alloc_skcipher(ctr_name, 0, 0);
1767	if (IS_ERR(sk_tfm)) {
1768		pr_info("DRBG: could not allocate CTR cipher TFM handle: %s\n",
1769				ctr_name);
1770		drbg_fini_sym_kernel(drbg);
1771		return PTR_ERR(sk_tfm);
1772	}
1773	drbg->ctr_handle = sk_tfm;
1774	crypto_init_wait(&drbg->ctr_wait);
1775
1776	req = skcipher_request_alloc(sk_tfm, GFP_KERNEL);
1777	if (!req) {
1778		pr_info("DRBG: could not allocate request queue\n");
1779		drbg_fini_sym_kernel(drbg);
1780		return -ENOMEM;
1781	}
1782	drbg->ctr_req = req;
1783	skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
1784						CRYPTO_TFM_REQ_MAY_SLEEP,
1785					crypto_req_done, &drbg->ctr_wait);
1786
1787	alignmask = crypto_skcipher_alignmask(sk_tfm);
1788	drbg->outscratchpadbuf = kmalloc(DRBG_OUTSCRATCHLEN + alignmask,
1789					 GFP_KERNEL);
1790	if (!drbg->outscratchpadbuf) {
1791		drbg_fini_sym_kernel(drbg);
1792		return -ENOMEM;
1793	}
1794	drbg->outscratchpad = (u8 *)PTR_ALIGN(drbg->outscratchpadbuf,
1795					      alignmask + 1);
1796
1797	sg_init_table(&drbg->sg_in, 1);
1798	sg_init_one(&drbg->sg_out, drbg->outscratchpad, DRBG_OUTSCRATCHLEN);
1799
1800	return alignmask;
1801}
1802
1803static void drbg_kcapi_symsetkey(struct drbg_state *drbg,
1804				 const unsigned char *key)
1805{
1806	struct crypto_cipher *tfm = drbg->priv_data;
 
1807
1808	crypto_cipher_setkey(tfm, key, (drbg_keylen(drbg)));
1809}
1810
1811static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval,
1812			  const struct drbg_string *in)
1813{
1814	struct crypto_cipher *tfm = drbg->priv_data;
 
1815
1816	/* there is only component in *in */
1817	BUG_ON(in->len < drbg_blocklen(drbg));
1818	crypto_cipher_encrypt_one(tfm, outval, in->buf);
1819	return 0;
1820}
1821
1822static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
1823			      u8 *inbuf, u32 inlen,
1824			      u8 *outbuf, u32 outlen)
1825{
1826	struct scatterlist *sg_in = &drbg->sg_in, *sg_out = &drbg->sg_out;
1827	u32 scratchpad_use = min_t(u32, outlen, DRBG_OUTSCRATCHLEN);
1828	int ret;
1829
1830	if (inbuf) {
1831		/* Use caller-provided input buffer */
1832		sg_set_buf(sg_in, inbuf, inlen);
1833	} else {
1834		/* Use scratchpad for in-place operation */
1835		inlen = scratchpad_use;
1836		memset(drbg->outscratchpad, 0, scratchpad_use);
1837		sg_set_buf(sg_in, drbg->outscratchpad, scratchpad_use);
1838	}
1839
1840	while (outlen) {
1841		u32 cryptlen = min3(inlen, outlen, (u32)DRBG_OUTSCRATCHLEN);
1842
1843		/* Output buffer may not be valid for SGL, use scratchpad */
1844		skcipher_request_set_crypt(drbg->ctr_req, sg_in, sg_out,
1845					   cryptlen, drbg->V);
1846		ret = crypto_wait_req(crypto_skcipher_encrypt(drbg->ctr_req),
1847					&drbg->ctr_wait);
1848		if (ret)
1849			goto out;
1850
1851		crypto_init_wait(&drbg->ctr_wait);
1852
1853		memcpy(outbuf, drbg->outscratchpad, cryptlen);
1854		memzero_explicit(drbg->outscratchpad, cryptlen);
1855
1856		outlen -= cryptlen;
1857		outbuf += cryptlen;
1858	}
1859	ret = 0;
1860
1861out:
1862	return ret;
1863}
1864#endif /* CONFIG_CRYPTO_DRBG_CTR */
1865
1866/***************************************************************
1867 * Kernel crypto API interface to register DRBG
1868 ***************************************************************/
1869
1870/*
1871 * Look up the DRBG flags by given kernel crypto API cra_name
1872 * The code uses the drbg_cores definition to do this
1873 *
1874 * @cra_name kernel crypto API cra_name
1875 * @coreref reference to integer which is filled with the pointer to
1876 *  the applicable core
1877 * @pr reference for setting prediction resistance
1878 *
1879 * return: flags
1880 */
1881static inline void drbg_convert_tfm_core(const char *cra_driver_name,
1882					 int *coreref, bool *pr)
1883{
1884	int i = 0;
1885	size_t start = 0;
1886	int len = 0;
1887
1888	*pr = true;
1889	/* disassemble the names */
1890	if (!memcmp(cra_driver_name, "drbg_nopr_", 10)) {
1891		start = 10;
1892		*pr = false;
1893	} else if (!memcmp(cra_driver_name, "drbg_pr_", 8)) {
1894		start = 8;
1895	} else {
1896		return;
1897	}
1898
1899	/* remove the first part */
1900	len = strlen(cra_driver_name) - start;
1901	for (i = 0; ARRAY_SIZE(drbg_cores) > i; i++) {
1902		if (!memcmp(cra_driver_name + start, drbg_cores[i].cra_name,
1903			    len)) {
1904			*coreref = i;
1905			return;
1906		}
1907	}
1908}
1909
1910static int drbg_kcapi_init(struct crypto_tfm *tfm)
1911{
1912	struct drbg_state *drbg = crypto_tfm_ctx(tfm);
1913
1914	mutex_init(&drbg->drbg_mutex);
1915
1916	return 0;
1917}
1918
1919static void drbg_kcapi_cleanup(struct crypto_tfm *tfm)
1920{
1921	drbg_uninstantiate(crypto_tfm_ctx(tfm));
1922}
1923
1924/*
1925 * Generate random numbers invoked by the kernel crypto API:
1926 * The API of the kernel crypto API is extended as follows:
1927 *
1928 * src is additional input supplied to the RNG.
1929 * slen is the length of src.
1930 * dst is the output buffer where random data is to be stored.
1931 * dlen is the length of dst.
1932 */
1933static int drbg_kcapi_random(struct crypto_rng *tfm,
1934			     const u8 *src, unsigned int slen,
1935			     u8 *dst, unsigned int dlen)
1936{
1937	struct drbg_state *drbg = crypto_rng_ctx(tfm);
1938	struct drbg_string *addtl = NULL;
1939	struct drbg_string string;
1940
1941	if (slen) {
1942		/* linked list variable is now local to allow modification */
1943		drbg_string_fill(&string, src, slen);
1944		addtl = &string;
1945	}
1946
1947	return drbg_generate_long(drbg, dst, dlen, addtl);
1948}
1949
1950/*
1951 * Seed the DRBG invoked by the kernel crypto API
1952 */
1953static int drbg_kcapi_seed(struct crypto_rng *tfm,
1954			   const u8 *seed, unsigned int slen)
1955{
1956	struct drbg_state *drbg = crypto_rng_ctx(tfm);
1957	struct crypto_tfm *tfm_base = crypto_rng_tfm(tfm);
1958	bool pr = false;
1959	struct drbg_string string;
1960	struct drbg_string *seed_string = NULL;
1961	int coreref = 0;
1962
1963	drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base), &coreref,
1964			      &pr);
1965	if (0 < slen) {
1966		drbg_string_fill(&string, seed, slen);
1967		seed_string = &string;
1968	}
1969
1970	return drbg_instantiate(drbg, seed_string, coreref, pr);
1971}
1972
1973/***************************************************************
1974 * Kernel module: code to load the module
1975 ***************************************************************/
1976
1977/*
1978 * Tests as defined in 11.3.2 in addition to the cipher tests: testing
1979 * of the error handling.
1980 *
1981 * Note: testing of failing seed source as defined in 11.3.2 is not applicable
1982 * as seed source of get_random_bytes does not fail.
1983 *
1984 * Note 2: There is no sensible way of testing the reseed counter
1985 * enforcement, so skip it.
1986 */
1987static inline int __init drbg_healthcheck_sanity(void)
1988{
1989	int len = 0;
1990#define OUTBUFLEN 16
1991	unsigned char buf[OUTBUFLEN];
1992	struct drbg_state *drbg = NULL;
1993	int ret;
1994	int rc = -EFAULT;
1995	bool pr = false;
1996	int coreref = 0;
1997	struct drbg_string addtl;
1998	size_t max_addtllen, max_request_bytes;
1999
2000	/* only perform test in FIPS mode */
2001	if (!fips_enabled)
2002		return 0;
2003
2004#ifdef CONFIG_CRYPTO_DRBG_CTR
2005	drbg_convert_tfm_core("drbg_nopr_ctr_aes256", &coreref, &pr);
2006#endif
2007#ifdef CONFIG_CRYPTO_DRBG_HASH
2008	drbg_convert_tfm_core("drbg_nopr_sha256", &coreref, &pr);
2009#endif
2010#ifdef CONFIG_CRYPTO_DRBG_HMAC
2011	drbg_convert_tfm_core("drbg_nopr_hmac_sha512", &coreref, &pr);
2012#endif
2013
2014	drbg = kzalloc(sizeof(struct drbg_state), GFP_KERNEL);
2015	if (!drbg)
2016		return -ENOMEM;
2017
2018	mutex_init(&drbg->drbg_mutex);
2019	drbg->core = &drbg_cores[coreref];
2020	drbg->reseed_threshold = drbg_max_requests(drbg);
2021
2022	/*
2023	 * if the following tests fail, it is likely that there is a buffer
2024	 * overflow as buf is much smaller than the requested or provided
2025	 * string lengths -- in case the error handling does not succeed
2026	 * we may get an OOPS. And we want to get an OOPS as this is a
2027	 * grave bug.
2028	 */
2029
2030	max_addtllen = drbg_max_addtl(drbg);
2031	max_request_bytes = drbg_max_request_bytes(drbg);
2032	drbg_string_fill(&addtl, buf, max_addtllen + 1);
2033	/* overflow addtllen with additonal info string */
2034	len = drbg_generate(drbg, buf, OUTBUFLEN, &addtl);
2035	BUG_ON(0 < len);
2036	/* overflow max_bits */
2037	len = drbg_generate(drbg, buf, (max_request_bytes + 1), NULL);
2038	BUG_ON(0 < len);
2039
2040	/* overflow max addtllen with personalization string */
2041	ret = drbg_seed(drbg, &addtl, false);
2042	BUG_ON(0 == ret);
2043	/* all tests passed */
2044	rc = 0;
2045
2046	pr_devel("DRBG: Sanity tests for failure code paths successfully "
2047		 "completed\n");
2048
2049	kfree(drbg);
2050	return rc;
2051}
2052
2053static struct rng_alg drbg_algs[22];
2054
2055/*
2056 * Fill the array drbg_algs used to register the different DRBGs
2057 * with the kernel crypto API. To fill the array, the information
2058 * from drbg_cores[] is used.
2059 */
2060static inline void __init drbg_fill_array(struct rng_alg *alg,
2061					  const struct drbg_core *core, int pr)
2062{
2063	int pos = 0;
2064	static int priority = 200;
2065
2066	memcpy(alg->base.cra_name, "stdrng", 6);
2067	if (pr) {
2068		memcpy(alg->base.cra_driver_name, "drbg_pr_", 8);
2069		pos = 8;
2070	} else {
2071		memcpy(alg->base.cra_driver_name, "drbg_nopr_", 10);
2072		pos = 10;
2073	}
2074	memcpy(alg->base.cra_driver_name + pos, core->cra_name,
2075	       strlen(core->cra_name));
2076
2077	alg->base.cra_priority = priority;
2078	priority++;
2079	/*
2080	 * If FIPS mode enabled, the selected DRBG shall have the
2081	 * highest cra_priority over other stdrng instances to ensure
2082	 * it is selected.
2083	 */
2084	if (fips_enabled)
2085		alg->base.cra_priority += 200;
2086
2087	alg->base.cra_ctxsize 	= sizeof(struct drbg_state);
2088	alg->base.cra_module	= THIS_MODULE;
2089	alg->base.cra_init	= drbg_kcapi_init;
2090	alg->base.cra_exit	= drbg_kcapi_cleanup;
2091	alg->generate		= drbg_kcapi_random;
2092	alg->seed		= drbg_kcapi_seed;
2093	alg->set_ent		= drbg_kcapi_set_entropy;
2094	alg->seedsize		= 0;
2095}
2096
2097static int __init drbg_init(void)
2098{
2099	unsigned int i = 0; /* pointer to drbg_algs */
2100	unsigned int j = 0; /* pointer to drbg_cores */
2101	int ret;
2102
2103	ret = drbg_healthcheck_sanity();
2104	if (ret)
2105		return ret;
2106
2107	if (ARRAY_SIZE(drbg_cores) * 2 > ARRAY_SIZE(drbg_algs)) {
2108		pr_info("DRBG: Cannot register all DRBG types"
2109			"(slots needed: %zu, slots available: %zu)\n",
2110			ARRAY_SIZE(drbg_cores) * 2, ARRAY_SIZE(drbg_algs));
2111		return -EFAULT;
2112	}
2113
2114	/*
2115	 * each DRBG definition can be used with PR and without PR, thus
2116	 * we instantiate each DRBG in drbg_cores[] twice.
2117	 *
2118	 * As the order of placing them into the drbg_algs array matters
2119	 * (the later DRBGs receive a higher cra_priority) we register the
2120	 * prediction resistance DRBGs first as the should not be too
2121	 * interesting.
2122	 */
2123	for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
2124		drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 1);
2125	for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
2126		drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 0);
2127	return crypto_register_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
2128}
2129
2130static void __exit drbg_exit(void)
2131{
2132	crypto_unregister_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
2133}
2134
2135subsys_initcall(drbg_init);
2136module_exit(drbg_exit);
2137#ifndef CRYPTO_DRBG_HASH_STRING
2138#define CRYPTO_DRBG_HASH_STRING ""
2139#endif
2140#ifndef CRYPTO_DRBG_HMAC_STRING
2141#define CRYPTO_DRBG_HMAC_STRING ""
2142#endif
2143#ifndef CRYPTO_DRBG_CTR_STRING
2144#define CRYPTO_DRBG_CTR_STRING ""
2145#endif
2146MODULE_LICENSE("GPL");
2147MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
2148MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) "
2149		   "using following cores: "
2150		   CRYPTO_DRBG_HASH_STRING
2151		   CRYPTO_DRBG_HMAC_STRING
2152		   CRYPTO_DRBG_CTR_STRING);
2153MODULE_ALIAS_CRYPTO("stdrng");
2154MODULE_IMPORT_NS("CRYPTO_INTERNAL");