drbg.c 56 KB
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/*
 * DRBG: Deterministic Random Bits Generator
 *       Based on NIST Recommended DRBG from NIST SP800-90A with the following
 *       properties:
 *		* CTR DRBG with DF with AES-128, AES-192, AES-256 cores
 *		* Hash DRBG with DF with SHA-1, SHA-256, SHA-384, SHA-512 cores
 *		* HMAC DRBG with DF with SHA-1, SHA-256, SHA-384, SHA-512 cores
 *		* with and without prediction resistance
 *
 * Copyright Stephan Mueller <smueller@chronox.de>, 2014
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, and the entire permission notice in its entirety,
 *    including the disclaimer of warranties.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote
 *    products derived from this software without specific prior
 *    written permission.
 *
 * ALTERNATIVELY, this product may be distributed under the terms of
 * the GNU General Public License, in which case the provisions of the GPL are
 * required INSTEAD OF the above restrictions.  (This clause is
 * necessary due to a potential bad interaction between the GPL and
 * the restrictions contained in a BSD-style copyright.)
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
 * WHICH ARE HEREBY DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
 * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 *
 * DRBG Usage
 * ==========
 * The SP 800-90A DRBG allows the user to specify a personalization string
 * for initialization as well as an additional information string for each
 * random number request. The following code fragments show how a caller
 * uses the kernel crypto API to use the full functionality of the DRBG.
 *
 * Usage without any additional data
 * ---------------------------------
 * struct crypto_rng *drng;
 * int err;
 * char data[DATALEN];
 *
 * drng = crypto_alloc_rng(drng_name, 0, 0);
 * err = crypto_rng_get_bytes(drng, &data, DATALEN);
 * crypto_free_rng(drng);
 *
 *
 * Usage with personalization string during initialization
 * -------------------------------------------------------
 * struct crypto_rng *drng;
 * int err;
 * char data[DATALEN];
 * struct drbg_string pers;
 * char personalization[11] = "some-string";
 *
 * drbg_string_fill(&pers, personalization, strlen(personalization));
 * drng = crypto_alloc_rng(drng_name, 0, 0);
 * // The reset completely re-initializes the DRBG with the provided
 * // personalization string
 * err = crypto_rng_reset(drng, &personalization, strlen(personalization));
 * err = crypto_rng_get_bytes(drng, &data, DATALEN);
 * crypto_free_rng(drng);
 *
 *
 * Usage with additional information string during random number request
 * ---------------------------------------------------------------------
 * struct crypto_rng *drng;
 * int err;
 * char data[DATALEN];
 * char addtl_string[11] = "some-string";
 * string drbg_string addtl;
 *
 * drbg_string_fill(&addtl, addtl_string, strlen(addtl_string));
 * drng = crypto_alloc_rng(drng_name, 0, 0);
 * // The following call is a wrapper to crypto_rng_get_bytes() and returns
 * // the same error codes.
 * err = crypto_drbg_get_bytes_addtl(drng, &data, DATALEN, &addtl);
 * crypto_free_rng(drng);
 *
 *
 * Usage with personalization and additional information strings
 * -------------------------------------------------------------
 * Just mix both scenarios above.
 */

#include <crypto/drbg.h>
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#include <linux/kernel.h>
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/***************************************************************
 * Backend cipher definitions available to DRBG
 ***************************************************************/

/*
 * The order of the DRBG definitions here matter: every DRBG is registered
 * as stdrng. Each DRBG receives an increasing cra_priority values the later
 * they are defined in this array (see drbg_fill_array).
 *
 * HMAC DRBGs are favored over Hash DRBGs over CTR DRBGs, and
 * the SHA256 / AES 256 over other ciphers. Thus, the favored
 * DRBGs are the latest entries in this array.
 */
static const struct drbg_core drbg_cores[] = {
#ifdef CONFIG_CRYPTO_DRBG_CTR
	{
		.flags = DRBG_CTR | DRBG_STRENGTH128,
		.statelen = 32, /* 256 bits as defined in 10.2.1 */
		.blocklen_bytes = 16,
		.cra_name = "ctr_aes128",
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		.backend_cra_name = "aes",
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	}, {
		.flags = DRBG_CTR | DRBG_STRENGTH192,
		.statelen = 40, /* 320 bits as defined in 10.2.1 */
		.blocklen_bytes = 16,
		.cra_name = "ctr_aes192",
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		.backend_cra_name = "aes",
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	}, {
		.flags = DRBG_CTR | DRBG_STRENGTH256,
		.statelen = 48, /* 384 bits as defined in 10.2.1 */
		.blocklen_bytes = 16,
		.cra_name = "ctr_aes256",
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		.backend_cra_name = "aes",
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	},
#endif /* CONFIG_CRYPTO_DRBG_CTR */
#ifdef CONFIG_CRYPTO_DRBG_HASH
	{
		.flags = DRBG_HASH | DRBG_STRENGTH128,
		.statelen = 55, /* 440 bits */
		.blocklen_bytes = 20,
		.cra_name = "sha1",
		.backend_cra_name = "sha1",
	}, {
		.flags = DRBG_HASH | DRBG_STRENGTH256,
		.statelen = 111, /* 888 bits */
		.blocklen_bytes = 48,
		.cra_name = "sha384",
		.backend_cra_name = "sha384",
	}, {
		.flags = DRBG_HASH | DRBG_STRENGTH256,
		.statelen = 111, /* 888 bits */
		.blocklen_bytes = 64,
		.cra_name = "sha512",
		.backend_cra_name = "sha512",
	}, {
		.flags = DRBG_HASH | DRBG_STRENGTH256,
		.statelen = 55, /* 440 bits */
		.blocklen_bytes = 32,
		.cra_name = "sha256",
		.backend_cra_name = "sha256",
	},
#endif /* CONFIG_CRYPTO_DRBG_HASH */
#ifdef CONFIG_CRYPTO_DRBG_HMAC
	{
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		.flags = DRBG_HMAC | DRBG_STRENGTH128,
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		.statelen = 20, /* block length of cipher */
		.blocklen_bytes = 20,
		.cra_name = "hmac_sha1",
		.backend_cra_name = "hmac(sha1)",
	}, {
		.flags = DRBG_HMAC | DRBG_STRENGTH256,
		.statelen = 48, /* block length of cipher */
		.blocklen_bytes = 48,
		.cra_name = "hmac_sha384",
		.backend_cra_name = "hmac(sha384)",
	}, {
		.flags = DRBG_HMAC | DRBG_STRENGTH256,
		.statelen = 64, /* block length of cipher */
		.blocklen_bytes = 64,
		.cra_name = "hmac_sha512",
		.backend_cra_name = "hmac(sha512)",
	}, {
		.flags = DRBG_HMAC | DRBG_STRENGTH256,
		.statelen = 32, /* block length of cipher */
		.blocklen_bytes = 32,
		.cra_name = "hmac_sha256",
		.backend_cra_name = "hmac(sha256)",
	},
#endif /* CONFIG_CRYPTO_DRBG_HMAC */
};

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static int drbg_uninstantiate(struct drbg_state *drbg);

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/******************************************************************
 * Generic helper functions
 ******************************************************************/

/*
 * Return strength of DRBG according to SP800-90A section 8.4
 *
 * @flags DRBG flags reference
 *
 * Return: normalized strength in *bytes* value or 32 as default
 *	   to counter programming errors
 */
static inline unsigned short drbg_sec_strength(drbg_flag_t flags)
{
	switch (flags & DRBG_STRENGTH_MASK) {
	case DRBG_STRENGTH128:
		return 16;
	case DRBG_STRENGTH192:
		return 24;
	case DRBG_STRENGTH256:
		return 32;
	default:
		return 32;
	}
}

/*
 * FIPS 140-2 continuous self test
 * The test is performed on the result of one round of the output
 * function. Thus, the function implicitly knows the size of the
 * buffer.
 *
 * @drbg DRBG handle
 * @buf output buffer of random data to be checked
 *
 * return:
 *	true on success
 *	false on error
 */
static bool drbg_fips_continuous_test(struct drbg_state *drbg,
				      const unsigned char *buf)
{
#ifdef CONFIG_CRYPTO_FIPS
	int ret = 0;
	/* skip test if we test the overall system */
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	if (list_empty(&drbg->test_data.list))
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		return true;
	/* only perform test in FIPS mode */
	if (0 == fips_enabled)
		return true;
	if (!drbg->fips_primed) {
		/* Priming of FIPS test */
		memcpy(drbg->prev, buf, drbg_blocklen(drbg));
		drbg->fips_primed = true;
		/* return false due to priming, i.e. another round is needed */
		return false;
	}
	ret = memcmp(drbg->prev, buf, drbg_blocklen(drbg));
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	if (!ret)
		panic("DRBG continuous self test failed\n");
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	memcpy(drbg->prev, buf, drbg_blocklen(drbg));
	/* the test shall pass when the two compared values are not equal */
	return ret != 0;
#else
	return true;
#endif /* CONFIG_CRYPTO_FIPS */
}

/*
 * Convert an integer into a byte representation of this integer.
 * The byte representation is big-endian
 *
 * @val value to be converted
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 * @buf buffer holding the converted integer -- caller must ensure that
 *      buffer size is at least 32 bit
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 */
#if (defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR))
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static inline void drbg_cpu_to_be32(__u32 val, unsigned char *buf)
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{
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	struct s {
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		__be32 conv;
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	};
	struct s *conversion = (struct s *) buf;
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	conversion->conv = cpu_to_be32(val);
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}
#endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */

/******************************************************************
 * CTR DRBG callback functions
 ******************************************************************/

#ifdef CONFIG_CRYPTO_DRBG_CTR
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#define CRYPTO_DRBG_CTR_STRING "CTR "
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MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes256");
MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes256");
MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes192");
MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes192");
MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes128");
MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes128");
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static int drbg_kcapi_sym(struct drbg_state *drbg, const unsigned char *key,
			  unsigned char *outval, const struct drbg_string *in);
static int drbg_init_sym_kernel(struct drbg_state *drbg);
static int drbg_fini_sym_kernel(struct drbg_state *drbg);

/* BCC function for CTR DRBG as defined in 10.4.3 */
static int drbg_ctr_bcc(struct drbg_state *drbg,
			unsigned char *out, const unsigned char *key,
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			struct list_head *in)
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{
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	int ret = 0;
	struct drbg_string *curr = NULL;
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	struct drbg_string data;
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	short cnt = 0;
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	drbg_string_fill(&data, out, drbg_blocklen(drbg));

	/* 10.4.3 step 2 / 4 */
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	list_for_each_entry(curr, in, list) {
		const unsigned char *pos = curr->buf;
		size_t len = curr->len;
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		/* 10.4.3 step 4.1 */
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		while (len) {
			/* 10.4.3 step 4.2 */
			if (drbg_blocklen(drbg) == cnt) {
				cnt = 0;
				ret = drbg_kcapi_sym(drbg, key, out, &data);
				if (ret)
					return ret;
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			}
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			out[cnt] ^= *pos;
			pos++;
			cnt++;
			len--;
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		}
	}
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	/* 10.4.3 step 4.2 for last block */
	if (cnt)
		ret = drbg_kcapi_sym(drbg, key, out, &data);

	return ret;
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}

/*
 * scratchpad usage: drbg_ctr_update is interlinked with drbg_ctr_df
 * (and drbg_ctr_bcc, but this function does not need any temporary buffers),
 * the scratchpad is used as follows:
 * drbg_ctr_update:
 *	temp
 *		start: drbg->scratchpad
 *		length: drbg_statelen(drbg) + drbg_blocklen(drbg)
 *			note: the cipher writing into this variable works
 *			blocklen-wise. Now, when the statelen is not a multiple
 *			of blocklen, the generateion loop below "spills over"
 *			by at most blocklen. Thus, we need to give sufficient
 *			memory.
 *	df_data
 *		start: drbg->scratchpad +
 *				drbg_statelen(drbg) + drbg_blocklen(drbg)
 *		length: drbg_statelen(drbg)
 *
 * drbg_ctr_df:
 *	pad
 *		start: df_data + drbg_statelen(drbg)
 *		length: drbg_blocklen(drbg)
 *	iv
 *		start: pad + drbg_blocklen(drbg)
 *		length: drbg_blocklen(drbg)
 *	temp
 *		start: iv + drbg_blocklen(drbg)
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 *		length: drbg_satelen(drbg) + drbg_blocklen(drbg)
 *			note: temp is the buffer that the BCC function operates
 *			on. BCC operates blockwise. drbg_statelen(drbg)
 *			is sufficient when the DRBG state length is a multiple
 *			of the block size. For AES192 (and maybe other ciphers)
 *			this is not correct and the length for temp is
 *			insufficient (yes, that also means for such ciphers,
 *			the final output of all BCC rounds are truncated).
 *			Therefore, add drbg_blocklen(drbg) to cover all
 *			possibilities.
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 */

/* Derivation Function for CTR DRBG as defined in 10.4.2 */
static int drbg_ctr_df(struct drbg_state *drbg,
		       unsigned char *df_data, size_t bytes_to_return,
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		       struct list_head *seedlist)
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{
	int ret = -EFAULT;
	unsigned char L_N[8];
	/* S3 is input */
	struct drbg_string S1, S2, S4, cipherin;
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	LIST_HEAD(bcc_list);
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	unsigned char *pad = df_data + drbg_statelen(drbg);
	unsigned char *iv = pad + drbg_blocklen(drbg);
	unsigned char *temp = iv + drbg_blocklen(drbg);
	size_t padlen = 0;
	unsigned int templen = 0;
	/* 10.4.2 step 7 */
	unsigned int i = 0;
	/* 10.4.2 step 8 */
	const unsigned char *K = (unsigned char *)
			   "\x00\x01\x02\x03\x04\x05\x06\x07"
			   "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
			   "\x10\x11\x12\x13\x14\x15\x16\x17"
			   "\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f";
	unsigned char *X;
	size_t generated_len = 0;
	size_t inputlen = 0;
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	struct drbg_string *seed = NULL;
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	memset(pad, 0, drbg_blocklen(drbg));
	memset(iv, 0, drbg_blocklen(drbg));

	/* 10.4.2 step 1 is implicit as we work byte-wise */

	/* 10.4.2 step 2 */
	if ((512/8) < bytes_to_return)
		return -EINVAL;

	/* 10.4.2 step 2 -- calculate the entire length of all input data */
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	list_for_each_entry(seed, seedlist, list)
		inputlen += seed->len;
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	drbg_cpu_to_be32(inputlen, &L_N[0]);
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	/* 10.4.2 step 3 */
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	drbg_cpu_to_be32(bytes_to_return, &L_N[4]);
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	/* 10.4.2 step 5: length is L_N, input_string, one byte, padding */
	padlen = (inputlen + sizeof(L_N) + 1) % (drbg_blocklen(drbg));
	/* wrap the padlen appropriately */
	if (padlen)
		padlen = drbg_blocklen(drbg) - padlen;
	/*
	 * pad / padlen contains the 0x80 byte and the following zero bytes.
	 * As the calculated padlen value only covers the number of zero
	 * bytes, this value has to be incremented by one for the 0x80 byte.
	 */
	padlen++;
	pad[0] = 0x80;

	/* 10.4.2 step 4 -- first fill the linked list and then order it */
	drbg_string_fill(&S1, iv, drbg_blocklen(drbg));
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	list_add_tail(&S1.list, &bcc_list);
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	drbg_string_fill(&S2, L_N, sizeof(L_N));
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	list_add_tail(&S2.list, &bcc_list);
	list_splice_tail(seedlist, &bcc_list);
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	drbg_string_fill(&S4, pad, padlen);
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	list_add_tail(&S4.list, &bcc_list);
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	/* 10.4.2 step 9 */
	while (templen < (drbg_keylen(drbg) + (drbg_blocklen(drbg)))) {
		/*
		 * 10.4.2 step 9.1 - the padding is implicit as the buffer
		 * holds zeros after allocation -- even the increment of i
		 * is irrelevant as the increment remains within length of i
		 */
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		drbg_cpu_to_be32(i, iv);
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		/* 10.4.2 step 9.2 -- BCC and concatenation with temp */
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		ret = drbg_ctr_bcc(drbg, temp + templen, K, &bcc_list);
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		if (ret)
			goto out;
		/* 10.4.2 step 9.3 */
		i++;
		templen += drbg_blocklen(drbg);
	}

	/* 10.4.2 step 11 */
	X = temp + (drbg_keylen(drbg));
	drbg_string_fill(&cipherin, X, drbg_blocklen(drbg));

	/* 10.4.2 step 12: overwriting of outval is implemented in next step */

	/* 10.4.2 step 13 */
	while (generated_len < bytes_to_return) {
		short blocklen = 0;
		/*
		 * 10.4.2 step 13.1: the truncation of the key length is
		 * implicit as the key is only drbg_blocklen in size based on
		 * the implementation of the cipher function callback
		 */
		ret = drbg_kcapi_sym(drbg, temp, X, &cipherin);
		if (ret)
			goto out;
		blocklen = (drbg_blocklen(drbg) <
				(bytes_to_return - generated_len)) ?
			    drbg_blocklen(drbg) :
				(bytes_to_return - generated_len);
		/* 10.4.2 step 13.2 and 14 */
		memcpy(df_data + generated_len, X, blocklen);
		generated_len += blocklen;
	}

	ret = 0;

out:
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	memset(iv, 0, drbg_blocklen(drbg));
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	memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
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	memset(pad, 0, drbg_blocklen(drbg));
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	return ret;
}

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/*
 * update function of CTR DRBG as defined in 10.2.1.2
 *
 * The reseed variable has an enhanced meaning compared to the update
 * functions of the other DRBGs as follows:
 * 0 => initial seed from initialization
 * 1 => reseed via drbg_seed
 * 2 => first invocation from drbg_ctr_update when addtl is present. In
 *      this case, the df_data scratchpad is not deleted so that it is
 *      available for another calls to prevent calling the DF function
 *      again.
 * 3 => second invocation from drbg_ctr_update. When the update function
 *      was called with addtl, the df_data memory already contains the
 *      DFed addtl information and we do not need to call DF again.
 */
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static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed,
			   int reseed)
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{
	int ret = -EFAULT;
	/* 10.2.1.2 step 1 */
	unsigned char *temp = drbg->scratchpad;
	unsigned char *df_data = drbg->scratchpad + drbg_statelen(drbg) +
				 drbg_blocklen(drbg);
	unsigned char *temp_p, *df_data_p; /* pointer to iterate over buffers */
	unsigned int len = 0;
	struct drbg_string cipherin;

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	if (3 > reseed)
		memset(df_data, 0, drbg_statelen(drbg));
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	/* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */
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	if (seed) {
		ret = drbg_ctr_df(drbg, df_data, drbg_statelen(drbg), seed);
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		if (ret)
			goto out;
	}

	drbg_string_fill(&cipherin, drbg->V, drbg_blocklen(drbg));
	/*
	 * 10.2.1.3.2 steps 2 and 3 are already covered as the allocation
	 * zeroizes all memory during initialization
	 */
	while (len < (drbg_statelen(drbg))) {
		/* 10.2.1.2 step 2.1 */
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		crypto_inc(drbg->V, drbg_blocklen(drbg));
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		/*
		 * 10.2.1.2 step 2.2 */
		ret = drbg_kcapi_sym(drbg, drbg->C, temp + len, &cipherin);
		if (ret)
			goto out;
		/* 10.2.1.2 step 2.3 and 3 */
		len += drbg_blocklen(drbg);
	}

	/* 10.2.1.2 step 4 */
	temp_p = temp;
	df_data_p = df_data;
	for (len = 0; len < drbg_statelen(drbg); len++) {
		*temp_p ^= *df_data_p;
		df_data_p++; temp_p++;
	}

	/* 10.2.1.2 step 5 */
	memcpy(drbg->C, temp, drbg_keylen(drbg));
	/* 10.2.1.2 step 6 */
	memcpy(drbg->V, temp + drbg_keylen(drbg), drbg_blocklen(drbg));
	ret = 0;

out:
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	memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
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	if (2 != reseed)
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		memset(df_data, 0, drbg_statelen(drbg));
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	return ret;
}

/*
 * scratchpad use: drbg_ctr_update is called independently from
 * drbg_ctr_extract_bytes. Therefore, the scratchpad is reused
 */
/* Generate function of CTR DRBG as defined in 10.2.1.5.2 */
static int drbg_ctr_generate(struct drbg_state *drbg,
			     unsigned char *buf, unsigned int buflen,
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			     struct list_head *addtl)
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{
	int len = 0;
	int ret = 0;
	struct drbg_string data;

	/* 10.2.1.5.2 step 2 */
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	if (addtl && !list_empty(addtl)) {
		ret = drbg_ctr_update(drbg, addtl, 2);
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		if (ret)
			return 0;
	}

	/* 10.2.1.5.2 step 4.1 */
594
	crypto_inc(drbg->V, drbg_blocklen(drbg));
595 596 597 598 599 600 601 602 603 604 605 606 607
	drbg_string_fill(&data, drbg->V, drbg_blocklen(drbg));
	while (len < buflen) {
		int outlen = 0;
		/* 10.2.1.5.2 step 4.2 */
		ret = drbg_kcapi_sym(drbg, drbg->C, drbg->scratchpad, &data);
		if (ret) {
			len = ret;
			goto out;
		}
		outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
			  drbg_blocklen(drbg) : (buflen - len);
		if (!drbg_fips_continuous_test(drbg, drbg->scratchpad)) {
			/* 10.2.1.5.2 step 6 */
608
			crypto_inc(drbg->V, drbg_blocklen(drbg));
609 610 611 612 613 614 615
			continue;
		}
		/* 10.2.1.5.2 step 4.3 */
		memcpy(buf + len, drbg->scratchpad, outlen);
		len += outlen;
		/* 10.2.1.5.2 step 6 */
		if (len < buflen)
616
			crypto_inc(drbg->V, drbg_blocklen(drbg));
617 618
	}

619 620
	/* 10.2.1.5.2 step 6 */
	ret = drbg_ctr_update(drbg, NULL, 3);
621 622 623 624
	if (ret)
		len = ret;

out:
625
	memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642
	return len;
}

static struct drbg_state_ops drbg_ctr_ops = {
	.update		= drbg_ctr_update,
	.generate	= drbg_ctr_generate,
	.crypto_init	= drbg_init_sym_kernel,
	.crypto_fini	= drbg_fini_sym_kernel,
};
#endif /* CONFIG_CRYPTO_DRBG_CTR */

/******************************************************************
 * HMAC DRBG callback functions
 ******************************************************************/

#if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
static int drbg_kcapi_hash(struct drbg_state *drbg, const unsigned char *key,
643
			   unsigned char *outval, const struct list_head *in);
644 645 646 647 648
static int drbg_init_hash_kernel(struct drbg_state *drbg);
static int drbg_fini_hash_kernel(struct drbg_state *drbg);
#endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */

#ifdef CONFIG_CRYPTO_DRBG_HMAC
649
#define CRYPTO_DRBG_HMAC_STRING "HMAC "
650 651 652 653 654 655 656 657
MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha512");
MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha512");
MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha384");
MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha384");
MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha256");
MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha256");
MODULE_ALIAS_CRYPTO("drbg_pr_hmac_sha1");
MODULE_ALIAS_CRYPTO("drbg_nopr_hmac_sha1");
658

659
/* update function of HMAC DRBG as defined in 10.1.2.2 */
660 661
static int drbg_hmac_update(struct drbg_state *drbg, struct list_head *seed,
			    int reseed)
662 663 664
{
	int ret = -EFAULT;
	int i = 0;
665 666 667
	struct drbg_string seed1, seed2, vdata;
	LIST_HEAD(seedlist);
	LIST_HEAD(vdatalist);
668

669 670
	if (!reseed)
		/* 10.1.2.3 step 2 -- memset(0) of C is implicit with kzalloc */
671 672 673
		memset(drbg->V, 1, drbg_statelen(drbg));

	drbg_string_fill(&seed1, drbg->V, drbg_statelen(drbg));
674
	list_add_tail(&seed1.list, &seedlist);
675 676
	/* buffer of seed2 will be filled in for loop below with one byte */
	drbg_string_fill(&seed2, NULL, 1);
677
	list_add_tail(&seed2.list, &seedlist);
678
	/* input data of seed is allowed to be NULL at this point */
679 680
	if (seed)
		list_splice_tail(seed, &seedlist);
681

682 683
	drbg_string_fill(&vdata, drbg->V, drbg_statelen(drbg));
	list_add_tail(&vdata.list, &vdatalist);
684 685 686 687 688 689 690
	for (i = 2; 0 < i; i--) {
		/* first round uses 0x0, second 0x1 */
		unsigned char prefix = DRBG_PREFIX0;
		if (1 == i)
			prefix = DRBG_PREFIX1;
		/* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */
		seed2.buf = &prefix;
691
		ret = drbg_kcapi_hash(drbg, drbg->C, drbg->C, &seedlist);
692 693 694 695
		if (ret)
			return ret;

		/* 10.1.2.2 step 2 and 5 -- HMAC for V */
696
		ret = drbg_kcapi_hash(drbg, drbg->C, drbg->V, &vdatalist);
697 698 699 700
		if (ret)
			return ret;

		/* 10.1.2.2 step 3 */
701
		if (!seed)
702 703 704 705 706 707 708 709 710 711
			return ret;
	}

	return 0;
}

/* generate function of HMAC DRBG as defined in 10.1.2.5 */
static int drbg_hmac_generate(struct drbg_state *drbg,
			      unsigned char *buf,
			      unsigned int buflen,
712
			      struct list_head *addtl)
713 714 715 716
{
	int len = 0;
	int ret = 0;
	struct drbg_string data;
717
	LIST_HEAD(datalist);
718 719

	/* 10.1.2.5 step 2 */
720 721
	if (addtl && !list_empty(addtl)) {
		ret = drbg_hmac_update(drbg, addtl, 1);
722 723 724 725 726
		if (ret)
			return ret;
	}

	drbg_string_fill(&data, drbg->V, drbg_statelen(drbg));
727
	list_add_tail(&data.list, &datalist);
728 729 730
	while (len < buflen) {
		unsigned int outlen = 0;
		/* 10.1.2.5 step 4.1 */
731
		ret = drbg_kcapi_hash(drbg, drbg->C, drbg->V, &datalist);
732 733 734 735 736 737 738 739 740 741 742 743 744
		if (ret)
			return ret;
		outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
			  drbg_blocklen(drbg) : (buflen - len);
		if (!drbg_fips_continuous_test(drbg, drbg->V))
			continue;

		/* 10.1.2.5 step 4.2 */
		memcpy(buf + len, drbg->V, outlen);
		len += outlen;
	}

	/* 10.1.2.5 step 6 */
745 746 747
	if (addtl && !list_empty(addtl))
		ret = drbg_hmac_update(drbg, addtl, 1);
	else
748
		ret = drbg_hmac_update(drbg, NULL, 1);
749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767
	if (ret)
		return ret;

	return len;
}

static struct drbg_state_ops drbg_hmac_ops = {
	.update		= drbg_hmac_update,
	.generate	= drbg_hmac_generate,
	.crypto_init	= drbg_init_hash_kernel,
	.crypto_fini	= drbg_fini_hash_kernel,
};
#endif /* CONFIG_CRYPTO_DRBG_HMAC */

/******************************************************************
 * Hash DRBG callback functions
 ******************************************************************/

#ifdef CONFIG_CRYPTO_DRBG_HASH
768
#define CRYPTO_DRBG_HASH_STRING "HASH "
769 770 771 772 773 774 775 776
MODULE_ALIAS_CRYPTO("drbg_pr_sha512");
MODULE_ALIAS_CRYPTO("drbg_nopr_sha512");
MODULE_ALIAS_CRYPTO("drbg_pr_sha384");
MODULE_ALIAS_CRYPTO("drbg_nopr_sha384");
MODULE_ALIAS_CRYPTO("drbg_pr_sha256");
MODULE_ALIAS_CRYPTO("drbg_nopr_sha256");
MODULE_ALIAS_CRYPTO("drbg_pr_sha1");
MODULE_ALIAS_CRYPTO("drbg_nopr_sha1");
777

778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809
/*
 * Increment buffer
 *
 * @dst buffer to increment
 * @add value to add
 */
static inline void drbg_add_buf(unsigned char *dst, size_t dstlen,
				const unsigned char *add, size_t addlen)
{
	/* implied: dstlen > addlen */
	unsigned char *dstptr;
	const unsigned char *addptr;
	unsigned int remainder = 0;
	size_t len = addlen;

	dstptr = dst + (dstlen-1);
	addptr = add + (addlen-1);
	while (len) {
		remainder += *dstptr + *addptr;
		*dstptr = remainder & 0xff;
		remainder >>= 8;
		len--; dstptr--; addptr--;
	}
	len = dstlen - addlen;
	while (len && remainder > 0) {
		remainder = *dstptr + 1;
		*dstptr = remainder & 0xff;
		remainder >>= 8;
		len--; dstptr--;
	}
}

810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827
/*
 * scratchpad usage: as drbg_hash_update and drbg_hash_df are used
 * interlinked, the scratchpad is used as follows:
 * drbg_hash_update
 *	start: drbg->scratchpad
 *	length: drbg_statelen(drbg)
 * drbg_hash_df:
 *	start: drbg->scratchpad + drbg_statelen(drbg)
 *	length: drbg_blocklen(drbg)
 *
 * drbg_hash_process_addtl uses the scratchpad, but fully completes
 * before either of the functions mentioned before are invoked. Therefore,
 * drbg_hash_process_addtl does not need to be specifically considered.
 */

/* Derivation Function for Hash DRBG as defined in 10.4.1 */
static int drbg_hash_df(struct drbg_state *drbg,
			unsigned char *outval, size_t outlen,
828
			struct list_head *entropylist)
829 830 831 832 833
{
	int ret = 0;
	size_t len = 0;
	unsigned char input[5];
	unsigned char *tmp = drbg->scratchpad + drbg_statelen(drbg);
834
	struct drbg_string data;
835 836 837

	/* 10.4.1 step 3 */
	input[0] = 1;
838
	drbg_cpu_to_be32((outlen * 8), &input[1]);
839 840

	/* 10.4.1 step 4.1 -- concatenation of data for input into hash */
841 842
	drbg_string_fill(&data, input, 5);
	list_add(&data.list, entropylist);
843 844 845 846 847

	/* 10.4.1 step 4 */
	while (len < outlen) {
		short blocklen = 0;
		/* 10.4.1 step 4.1 */
848
		ret = drbg_kcapi_hash(drbg, NULL, tmp, entropylist);
849 850 851 852 853 854 855 856 857 858 859
		if (ret)
			goto out;
		/* 10.4.1 step 4.2 */
		input[0]++;
		blocklen = (drbg_blocklen(drbg) < (outlen - len)) ?
			    drbg_blocklen(drbg) : (outlen - len);
		memcpy(outval + len, tmp, blocklen);
		len += blocklen;
	}

out:
860
	memset(tmp, 0, drbg_blocklen(drbg));
861 862 863 864
	return ret;
}

/* update function for Hash DRBG as defined in 10.1.1.2 / 10.1.1.3 */
865
static int drbg_hash_update(struct drbg_state *drbg, struct list_head *seed,
866 867 868 869
			    int reseed)
{
	int ret = 0;
	struct drbg_string data1, data2;
870 871
	LIST_HEAD(datalist);
	LIST_HEAD(datalist2);
872 873 874 875 876 877 878 879 880 881
	unsigned char *V = drbg->scratchpad;
	unsigned char prefix = DRBG_PREFIX1;

	if (!seed)
		return -EINVAL;

	if (reseed) {
		/* 10.1.1.3 step 1 */
		memcpy(V, drbg->V, drbg_statelen(drbg));
		drbg_string_fill(&data1, &prefix, 1);
882
		list_add_tail(&data1.list, &datalist);
883
		drbg_string_fill(&data2, V, drbg_statelen(drbg));
884
		list_add_tail(&data2.list, &datalist);
885
	}
886
	list_splice_tail(seed, &datalist);
887 888

	/* 10.1.1.2 / 10.1.1.3 step 2 and 3 */
889
	ret = drbg_hash_df(drbg, drbg->V, drbg_statelen(drbg), &datalist);
890 891 892 893 894 895
	if (ret)
		goto out;

	/* 10.1.1.2 / 10.1.1.3 step 4  */
	prefix = DRBG_PREFIX0;
	drbg_string_fill(&data1, &prefix, 1);
896
	list_add_tail(&data1.list, &datalist2);
897
	drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
898
	list_add_tail(&data2.list, &datalist2);
899
	/* 10.1.1.2 / 10.1.1.3 step 4 */
900
	ret = drbg_hash_df(drbg, drbg->C, drbg_statelen(drbg), &datalist2);
901 902

out:
903
	memset(drbg->scratchpad, 0, drbg_statelen(drbg));
904 905 906 907 908
	return ret;
}

/* processing of additional information string for Hash DRBG */
static int drbg_hash_process_addtl(struct drbg_state *drbg,
909
				   struct list_head *addtl)
910 911 912
{
	int ret = 0;
	struct drbg_string data1, data2;
913
	LIST_HEAD(datalist);
914 915 916
	unsigned char prefix = DRBG_PREFIX2;

	/* 10.1.1.4 step 2 */
917
	if (!addtl || list_empty(addtl))
918 919 920 921 922
		return 0;

	/* 10.1.1.4 step 2a */
	drbg_string_fill(&data1, &prefix, 1);
	drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
923 924
	list_add_tail(&data1.list, &datalist);
	list_add_tail(&data2.list, &datalist);
925
	list_splice_tail(addtl, &datalist);
926
	ret = drbg_kcapi_hash(drbg, NULL, drbg->scratchpad, &datalist);
927 928 929 930 931 932 933 934
	if (ret)
		goto out;

	/* 10.1.1.4 step 2b */
	drbg_add_buf(drbg->V, drbg_statelen(drbg),
		     drbg->scratchpad, drbg_blocklen(drbg));

out:
935
	memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
936 937 938 939 940 941 942 943 944 945 946 947 948
	return ret;
}

/* Hashgen defined in 10.1.1.4 */
static int drbg_hash_hashgen(struct drbg_state *drbg,
			     unsigned char *buf,
			     unsigned int buflen)
{
	int len = 0;
	int ret = 0;
	unsigned char *src = drbg->scratchpad;
	unsigned char *dst = drbg->scratchpad + drbg_statelen(drbg);
	struct drbg_string data;
949
	LIST_HEAD(datalist);
950 951 952 953 954

	/* 10.1.1.4 step hashgen 2 */
	memcpy(src, drbg->V, drbg_statelen(drbg));

	drbg_string_fill(&data, src, drbg_statelen(drbg));
955
	list_add_tail(&data.list, &datalist);
956 957 958
	while (len < buflen) {
		unsigned int outlen = 0;
		/* 10.1.1.4 step hashgen 4.1 */
959
		ret = drbg_kcapi_hash(drbg, NULL, dst, &datalist);
960 961 962 963 964 965 966
		if (ret) {
			len = ret;
			goto out;
		}
		outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
			  drbg_blocklen(drbg) : (buflen - len);
		if (!drbg_fips_continuous_test(drbg, dst)) {
967
			crypto_inc(src, drbg_statelen(drbg));
968 969 970 971 972 973 974
			continue;
		}
		/* 10.1.1.4 step hashgen 4.2 */
		memcpy(buf + len, dst, outlen);
		len += outlen;
		/* 10.1.1.4 hashgen step 4.3 */
		if (len < buflen)
975
			crypto_inc(src, drbg_statelen(drbg));
976 977 978
	}

out:
979
	memset(drbg->scratchpad, 0,
980 981 982 983 984 985 986
	       (drbg_statelen(drbg) + drbg_blocklen(drbg)));
	return len;
}

/* generate function for Hash DRBG as defined in  10.1.1.4 */
static int drbg_hash_generate(struct drbg_state *drbg,
			      unsigned char *buf, unsigned int buflen,
987
			      struct list_head *addtl)
988 989 990
{
	int len = 0;
	int ret = 0;
991 992
	union {
		unsigned char req[8];
993
		__be64 req_int;
994
	} u;
995 996
	unsigned char prefix = DRBG_PREFIX3;
	struct drbg_string data1, data2;
997
	LIST_HEAD(datalist);
998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008

	/* 10.1.1.4 step 2 */
	ret = drbg_hash_process_addtl(drbg, addtl);
	if (ret)
		return ret;
	/* 10.1.1.4 step 3 */
	len = drbg_hash_hashgen(drbg, buf, buflen);

	/* this is the value H as documented in 10.1.1.4 */
	/* 10.1.1.4 step 4 */
	drbg_string_fill(&data1, &prefix, 1);
1009
	list_add_tail(&data1.list, &datalist);
1010
	drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
1011 1012
	list_add_tail(&data2.list, &datalist);
	ret = drbg_kcapi_hash(drbg, NULL, drbg->scratchpad, &datalist);
1013 1014 1015 1016 1017 1018 1019 1020 1021 1022
	if (ret) {
		len = ret;
		goto out;
	}

	/* 10.1.1.4 step 5 */
	drbg_add_buf(drbg->V, drbg_statelen(drbg),
		     drbg->scratchpad, drbg_blocklen(drbg));
	drbg_add_buf(drbg->V, drbg_statelen(drbg),
		     drbg->C, drbg_statelen(drbg));
1023 1024
	u.req_int = cpu_to_be64(drbg->reseed_ctr);
	drbg_add_buf(drbg->V, drbg_statelen(drbg), u.req, 8);
1025 1026

out:
1027
	memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046
	return len;
}

/*
 * scratchpad usage: as update and generate are used isolated, both
 * can use the scratchpad
 */
static struct drbg_state_ops drbg_hash_ops = {
	.update		= drbg_hash_update,
	.generate	= drbg_hash_generate,
	.crypto_init	= drbg_init_hash_kernel,
	.crypto_fini	= drbg_fini_hash_kernel,
};
#endif /* CONFIG_CRYPTO_DRBG_HASH */

/******************************************************************
 * Functions common for DRBG implementations
 ******************************************************************/

1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061
static inline int __drbg_seed(struct drbg_state *drbg, struct list_head *seed,
			      int reseed)
{
	int ret = drbg->d_ops->update(drbg, seed, reseed);

	if (ret)
		return ret;

	drbg->seeded = true;
	/* 10.1.1.2 / 10.1.1.3 step 5 */
	drbg->reseed_ctr = 1;

	return ret;
}

1062 1063 1064 1065 1066 1067
static void drbg_async_seed(struct work_struct *work)
{
	struct drbg_string data;
	LIST_HEAD(seedlist);
	struct drbg_state *drbg = container_of(work, struct drbg_state,
					       seed_work);
1068 1069
	unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
	unsigned char entropy[32];
1070

1071 1072 1073
	BUG_ON(!entropylen);
	BUG_ON(entropylen > sizeof(entropy));
	get_random_bytes(entropy, entropylen);
1074

1075
	drbg_string_fill(&data, entropy, entropylen);
1076
	list_add_tail(&data.list, &seedlist);
1077

1078
	mutex_lock(&drbg->drbg_mutex);
1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090

	/* If nonblocking pool is initialized, deactivate Jitter RNG */
	crypto_free_rng(drbg->jent);
	drbg->jent = NULL;

	/* Set seeded to false so that if __drbg_seed fails the
	 * next generate call will trigger a reseed.
	 */
	drbg->seeded = false;

	__drbg_seed(drbg, &seedlist, true);

1091 1092 1093
	if (drbg->seeded)
		drbg->reseed_threshold = drbg_max_requests(drbg);

1094
	mutex_unlock(&drbg->drbg_mutex);
1095 1096

	memzero_explicit(entropy, entropylen);
1097 1098
}

1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112
/*
 * Seeding or reseeding of the DRBG
 *
 * @drbg: DRBG state struct
 * @pers: personalization / additional information buffer
 * @reseed: 0 for initial seed process, 1 for reseeding
 *
 * return:
 *	0 on success
 *	error value otherwise
 */
static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
		     bool reseed)
{
1113 1114 1115
	int ret;
	unsigned char entropy[((32 + 16) * 2)];
	unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
1116
	struct drbg_string data1;
1117
	LIST_HEAD(seedlist);
1118 1119 1120

	/* 9.1 / 9.2 / 9.3.1 step 3 */
	if (pers && pers->len > (drbg_max_addtl(drbg))) {
1121
		pr_devel("DRBG: personalization string too long %zu\n",
1122 1123 1124 1125
			 pers->len);
		return -EINVAL;
	}

1126 1127 1128
	if (list_empty(&drbg->test_data.list)) {
		drbg_string_fill(&data1, drbg->test_data.buf,
				 drbg->test_data.len);
1129 1130
		pr_devel("DRBG: using test entropy\n");
	} else {
1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143
		/*
		 * Gather entropy equal to the security strength of the DRBG.
		 * With a derivation function, a nonce is required in addition
		 * to the entropy. A nonce must be at least 1/2 of the security
		 * strength of the DRBG in size. Thus, entropy + nonce is 3/2
		 * of the strength. The consideration of a nonce is only
		 * applicable during initial seeding.
		 */
		BUG_ON(!entropylen);
		if (!reseed)
			entropylen = ((entropylen + 1) / 2) * 3;
		BUG_ON((entropylen * 2) > sizeof(entropy));

1144
		/* Get seed from in-kernel /dev/urandom */
1145 1146 1147 1148 1149 1150
		get_random_bytes(entropy, entropylen);

		if (!drbg->jent) {
			drbg_string_fill(&data1, entropy, entropylen);
			pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
				 entropylen);
1151
		} else {
1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163
			/* Get seed from Jitter RNG */
			ret = crypto_rng_get_bytes(drbg->jent,
						   entropy + entropylen,
						   entropylen);
			if (ret) {
				pr_devel("DRBG: jent failed with %d\n", ret);
				return ret;
			}

			drbg_string_fill(&data1, entropy, entropylen * 2);
			pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
				 entropylen * 2);
1164
		}
1165
	}
1166
	list_add_tail(&data1.list, &seedlist);
1167 1168 1169 1170 1171 1172

	/*
	 * concatenation of entropy with personalization str / addtl input)
	 * the variable pers is directly handed in by the caller, so check its
	 * contents whether it is appropriate
	 */
1173 1174
	if (pers && pers->buf && 0 < pers->len) {
		list_add_tail(&pers->list, &seedlist);
1175 1176 1177
		pr_devel("DRBG: using personalization string\n");
	}

1178 1179 1180 1181 1182
	if (!reseed) {
		memset(drbg->V, 0, drbg_statelen(drbg));
		memset(drbg->C, 0, drbg_statelen(drbg));
	}

1183 1184
	ret = __drbg_seed(drbg, &seedlist, reseed);

1185
	memzero_explicit(entropy, entropylen * 2);
1186

1187 1188 1189 1190 1191 1192 1193 1194
	return ret;
}

/* Free all substructures in a DRBG state without the DRBG state structure */
static inline void drbg_dealloc_state(struct drbg_state *drbg)
{
	if (!drbg)
		return;
1195
	kzfree(drbg->V);
1196
	drbg->V = NULL;
1197
	kzfree(drbg->C);
1198
	drbg->C = NULL;
1199
	kzfree(drbg->scratchpad);
1200 1201
	drbg->scratchpad = NULL;
	drbg->reseed_ctr = 0;
1202 1203
	drbg->d_ops = NULL;
	drbg->core = NULL;
1204
#ifdef CONFIG_CRYPTO_FIPS
1205
	kzfree(drbg->prev);
1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219
	drbg->prev = NULL;
	drbg->fips_primed = false;
#endif
}

/*
 * Allocate all sub-structures for a DRBG state.
 * The DRBG state structure must already be allocated.
 */
static inline int drbg_alloc_state(struct drbg_state *drbg)
{
	int ret = -ENOMEM;
	unsigned int sb_size = 0;

1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240
	switch (drbg->core->flags & DRBG_TYPE_MASK) {
#ifdef CONFIG_CRYPTO_DRBG_HMAC
	case DRBG_HMAC:
		drbg->d_ops = &drbg_hmac_ops;
		break;
#endif /* CONFIG_CRYPTO_DRBG_HMAC */
#ifdef CONFIG_CRYPTO_DRBG_HASH
	case DRBG_HASH:
		drbg->d_ops = &drbg_hash_ops;
		break;
#endif /* CONFIG_CRYPTO_DRBG_HASH */
#ifdef CONFIG_CRYPTO_DRBG_CTR
	case DRBG_CTR:
		drbg->d_ops = &drbg_ctr_ops;
		break;
#endif /* CONFIG_CRYPTO_DRBG_CTR */
	default:
		ret = -EOPNOTSUPP;
		goto err;
	}

1241
	drbg->V = kmalloc(drbg_statelen(drbg), GFP_KERNEL);
1242 1243
	if (!drbg->V)
		goto err;
1244
	drbg->C = kmalloc(drbg_statelen(drbg), GFP_KERNEL);
1245 1246 1247
	if (!drbg->C)
		goto err;
#ifdef CONFIG_CRYPTO_FIPS
1248
	drbg->prev = kmalloc(drbg_blocklen(drbg), GFP_KERNEL);
1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260
	if (!drbg->prev)
		goto err;
	drbg->fips_primed = false;
#endif
	/* scratchpad is only generated for CTR and Hash */
	if (drbg->core->flags & DRBG_HMAC)
		sb_size = 0;
	else if (drbg->core->flags & DRBG_CTR)
		sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg) + /* temp */
			  drbg_statelen(drbg) +	/* df_data */
			  drbg_blocklen(drbg) +	/* pad */
			  drbg_blocklen(drbg) +	/* iv */
1261
			  drbg_statelen(drbg) + drbg_blocklen(drbg); /* temp */
1262 1263 1264 1265 1266 1267 1268 1269
	else
		sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg);

	if (0 < sb_size) {
		drbg->scratchpad = kzalloc(sb_size, GFP_KERNEL);
		if (!drbg->scratchpad)
			goto err;
	}
1270

1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295
	return 0;

err:
	drbg_dealloc_state(drbg);
	return ret;
}

/*************************************************************************
 * DRBG interface functions
 *************************************************************************/

/*
 * DRBG generate function as required by SP800-90A - this function
 * generates random numbers
 *
 * @drbg DRBG state handle
 * @buf Buffer where to store the random numbers -- the buffer must already
 *      be pre-allocated by caller
 * @buflen Length of output buffer - this value defines the number of random
 *	   bytes pulled from DRBG
 * @addtl Additional input that is mixed into state, may be NULL -- note
 *	  the entropy is pulled by the DRBG internally unconditionally
 *	  as defined in SP800-90A. The additional input is mixed into
 *	  the state in addition to the pulled entropy.
 *
1296
 * return: 0 when all bytes are generated; < 0 in case of an error
1297 1298 1299 1300 1301 1302
 */
static int drbg_generate(struct drbg_state *drbg,
			 unsigned char *buf, unsigned int buflen,
			 struct drbg_string *addtl)
{
	int len = 0;
1303
	LIST_HEAD(addtllist);
1304

1305 1306 1307 1308
	if (!drbg->core) {
		pr_devel("DRBG: not yet seeded\n");
		return -EINVAL;
	}
1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319
	if (0 == buflen || !buf) {
		pr_devel("DRBG: no output buffer provided\n");
		return -EINVAL;
	}
	if (addtl && NULL == addtl->buf && 0 < addtl->len) {
		pr_devel("DRBG: wrong format of additional information\n");
		return -EINVAL;
	}

	/* 9.3.1 step 2 */
	len = -EINVAL;
1320
	if (buflen > (drbg_max_request_bytes(drbg))) {
1321 1322 1323 1324 1325 1326 1327 1328
		pr_devel("DRBG: requested random numbers too large %u\n",
			 buflen);
		goto err;
	}

	/* 9.3.1 step 3 is implicit with the chosen DRBG */

	/* 9.3.1 step 4 */
1329
	if (addtl && addtl->len > (drbg_max_addtl(drbg))) {
1330 1331 1332 1333 1334 1335 1336 1337 1338 1339
		pr_devel("DRBG: additional information string too long %zu\n",
			 addtl->len);
		goto err;
	}
	/* 9.3.1 step 5 is implicit with the chosen DRBG */

	/*
	 * 9.3.1 step 6 and 9 supplemented by 9.3.2 step c is implemented
	 * here. The spec is a bit convoluted here, we make it simpler.
	 */
1340
	if (drbg->reseed_threshold < drbg->reseed_ctr)
1341
		drbg->seeded = false;
1342

1343
	if (drbg->pr || !drbg->seeded) {
1344 1345 1346 1347 1348
		pr_devel("DRBG: reseeding before generation (prediction "
			 "resistance: %s, state %s)\n",
			 drbg->pr ? "true" : "false",
			 drbg->seeded ? "seeded" : "unseeded");
		/* 9.3.1 steps 7.1 through 7.3 */
1349
		len = drbg_seed(drbg, addtl, true);
1350 1351 1352 1353 1354
		if (len)
			goto err;
		/* 9.3.1 step 7.4 */
		addtl = NULL;
	}
1355 1356 1357

	if (addtl && 0 < addtl->len)
		list_add_tail(&addtl->list, &addtllist);
1358
	/* 9.3.1 step 8 and 10 */
1359
	len = drbg->d_ops->generate(drbg, buf, buflen, &addtllist);
1360 1361

	/* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */
1362
	drbg->reseed_ctr++;
1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381
	if (0 >= len)
		goto err;

	/*
	 * Section 11.3.3 requires to re-perform self tests after some
	 * generated random numbers. The chosen value after which self
	 * test is performed is arbitrary, but it should be reasonable.
	 * However, we do not perform the self tests because of the following
	 * reasons: it is mathematically impossible that the initial self tests
	 * were successfully and the following are not. If the initial would
	 * pass and the following would not, the kernel integrity is violated.
	 * In this case, the entire kernel operation is questionable and it
	 * is unlikely that the integrity violation only affects the
	 * correct operation of the DRBG.
	 *
	 * Albeit the following code is commented out, it is provided in
	 * case somebody has a need to implement the test of 11.3.3.
	 */
#if 0
1382
	if (drbg->reseed_ctr && !(drbg->reseed_ctr % 4096)) {
1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407
		int err = 0;
		pr_devel("DRBG: start to perform self test\n");
		if (drbg->core->flags & DRBG_HMAC)
			err = alg_test("drbg_pr_hmac_sha256",
				       "drbg_pr_hmac_sha256", 0, 0);
		else if (drbg->core->flags & DRBG_CTR)
			err = alg_test("drbg_pr_ctr_aes128",
				       "drbg_pr_ctr_aes128", 0, 0);
		else
			err = alg_test("drbg_pr_sha256",
				       "drbg_pr_sha256", 0, 0);
		if (err) {
			pr_err("DRBG: periodical self test failed\n");
			/*
			 * uninstantiate implies that from now on, only errors
			 * are returned when reusing this DRBG cipher handle
			 */
			drbg_uninstantiate(drbg);
			return 0;
		} else {
			pr_devel("DRBG: self test successful\n");
		}
	}
#endif

1408 1409 1410 1411 1412
	/*
	 * All operations were successful, return 0 as mandated by
	 * the kernel crypto API interface.
	 */
	len = 0;
1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428
err:
	return len;
}

/*
 * Wrapper around drbg_generate which can pull arbitrary long strings
 * from the DRBG without hitting the maximum request limitation.
 *
 * Parameters: see drbg_generate
 * Return codes: see drbg_generate -- if one drbg_generate request fails,
 *		 the entire drbg_generate_long request fails
 */
static int drbg_generate_long(struct drbg_state *drbg,
			      unsigned char *buf, unsigned int buflen,
			      struct drbg_string *addtl)
{
1429
	unsigned int len = 0;
1430 1431
	unsigned int slice = 0;
	do {
1432
		int err = 0;
1433 1434 1435
		unsigned int chunk = 0;
		slice = ((buflen - len) / drbg_max_request_bytes(drbg));
		chunk = slice ? drbg_max_request_bytes(drbg) : (buflen - len);
1436
		mutex_lock(&drbg->drbg_mutex);
1437
		err = drbg_generate(drbg, buf + len, chunk, addtl);
1438
		mutex_unlock(&drbg->drbg_mutex);
1439 1440 1441
		if (0 > err)
			return err;
		len += chunk;
1442
	} while (slice > 0 && (len < buflen));
1443
	return 0;
1444 1445
}

1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483
static void drbg_schedule_async_seed(struct random_ready_callback *rdy)
{
	struct drbg_state *drbg = container_of(rdy, struct drbg_state,
					       random_ready);

	schedule_work(&drbg->seed_work);
}

static int drbg_prepare_hrng(struct drbg_state *drbg)
{
	int err;

	/* We do not need an HRNG in test mode. */
	if (list_empty(&drbg->test_data.list))
		return 0;

	INIT_WORK(&drbg->seed_work, drbg_async_seed);

	drbg->random_ready.owner = THIS_MODULE;
	drbg->random_ready.func = drbg_schedule_async_seed;

	err = add_random_ready_callback(&drbg->random_ready);

	switch (err) {
	case 0:
		break;

	case -EALREADY:
		err = 0;
		/* fall through */

	default:
		drbg->random_ready.func = NULL;
		return err;
	}

	drbg->jent = crypto_alloc_rng("jitterentropy_rng", 0, 0);

1484 1485 1486 1487 1488 1489
	/*
	 * Require frequent reseeds until the seed source is fully
	 * initialized.
	 */
	drbg->reseed_threshold = 50;

1490 1491 1492
	return err;
}

1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512
/*
 * DRBG instantiation function as required by SP800-90A - this function
 * sets up the DRBG handle, performs the initial seeding and all sanity
 * checks required by SP800-90A
 *
 * @drbg memory of state -- if NULL, new memory is allocated
 * @pers Personalization string that is mixed into state, may be NULL -- note
 *	 the entropy is pulled by the DRBG internally unconditionally
 *	 as defined in SP800-90A. The additional input is mixed into
 *	 the state in addition to the pulled entropy.
 * @coreref reference to core
 * @pr prediction resistance enabled
 *
 * return
 *	0 on success
 *	error value otherwise
 */
static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers,
			    int coreref, bool pr)
{
1513 1514
	int ret;
	bool reseed = true;
1515 1516 1517

	pr_devel("DRBG: Initializing DRBG core %d with prediction resistance "
		 "%s\n", coreref, pr ? "enabled" : "disabled");
1518
	mutex_lock(&drbg->drbg_mutex);
1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529

	/* 9.1 step 1 is implicit with the selected DRBG type */

	/*
	 * 9.1 step 2 is implicit as caller can select prediction resistance
	 * and the flag is copied into drbg->flags --
	 * all DRBG types support prediction resistance
	 */

	/* 9.1 step 4 is implicit in  drbg_sec_strength */

1530 1531 1532 1533
	if (!drbg->core) {
		drbg->core = &drbg_cores[coreref];
		drbg->pr = pr;
		drbg->seeded = false;
1534
		drbg->reseed_threshold = drbg_max_requests(drbg);
1535

1536 1537 1538 1539 1540 1541 1542 1543
		ret = drbg_alloc_state(drbg);
		if (ret)
			goto unlock;

		ret = -EFAULT;
		if (drbg->d_ops->crypto_init(drbg))
			goto err;

1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555
		ret = drbg_prepare_hrng(drbg);
		if (ret)
			goto free_everything;

		if (IS_ERR(drbg->jent)) {
			ret = PTR_ERR(drbg->jent);
			drbg->jent = NULL;
			if (fips_enabled || ret != -ENOENT)
				goto free_everything;
			pr_info("DRBG: Continuing without Jitter RNG\n");
		}

1556 1557 1558 1559 1560
		reseed = false;
	}

	ret = drbg_seed(drbg, pers, reseed);

1561 1562
	if (ret && !reseed)
		goto free_everything;
1563

1564
	mutex_unlock(&drbg->drbg_mutex);
1565
	return ret;
1566 1567 1568

err:
	drbg_dealloc_state(drbg);
1569 1570
unlock:
	mutex_unlock(&drbg->drbg_mutex);
1571
	return ret;
1572 1573 1574 1575 1576

free_everything:
	mutex_unlock(&drbg->drbg_mutex);
	drbg_uninstantiate(drbg);
	return ret;
1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589
}

/*
 * DRBG uninstantiate function as required by SP800-90A - this function
 * frees all buffers and the DRBG handle
 *
 * @drbg DRBG state handle
 *
 * return
 *	0 on success
 */
static int drbg_uninstantiate(struct drbg_state *drbg)
{
1590 1591 1592 1593 1594 1595 1596
	if (drbg->random_ready.func) {
		del_random_ready_callback(&drbg->random_ready);
		cancel_work_sync(&drbg->seed_work);
		crypto_free_rng(drbg->jent);
		drbg->jent = NULL;
	}

1597 1598
	if (drbg->d_ops)
		drbg->d_ops->crypto_fini(drbg);
1599 1600 1601 1602 1603 1604 1605 1606 1607
	drbg_dealloc_state(drbg);
	/* no scrubbing of test_data -- this shall survive an uninstantiate */
	return 0;
}

/*
 * Helper function for setting the test data in the DRBG
 *
 * @drbg DRBG state handle
1608 1609
 * @data test data
 * @len test data length
1610
 */
1611 1612
static void drbg_kcapi_set_entropy(struct crypto_rng *tfm,
				   const u8 *data, unsigned int len)
1613
{
1614 1615 1616 1617
	struct drbg_state *drbg = crypto_rng_ctx(tfm);

	mutex_lock(&drbg->drbg_mutex);
	drbg_string_fill(&drbg->test_data, data, len);
1618
	mutex_unlock(&drbg->drbg_mutex);
1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637
}

/***************************************************************
 * Kernel crypto API cipher invocations requested by DRBG
 ***************************************************************/

#if defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_HMAC)
struct sdesc {
	struct shash_desc shash;
	char ctx[];
};

static int drbg_init_hash_kernel(struct drbg_state *drbg)
{
	struct sdesc *sdesc;
	struct crypto_shash *tfm;

	tfm = crypto_alloc_shash(drbg->core->backend_cra_name, 0, 0);
	if (IS_ERR(tfm)) {
1638 1639
		pr_info("DRBG: could not allocate digest TFM handle: %s\n",
				drbg->core->backend_cra_name);