Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2138 insertions, 0 deletions

diff --git a/crypto/drbg.c b/crypto/drbg.c
new file mode 100644
index 000000000..c8c56763d
--- /dev/null
+++ b/crypto/drbg.c
@@ -0,0 +1,2138 @@
+/*
+ * 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>
+#include <linux/kernel.h>
+
+/***************************************************************
+ * 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",
+		.backend_cra_name = "aes",
+	}, {
+		.flags = DRBG_CTR | DRBG_STRENGTH192,
+		.statelen = 40, /* 320 bits as defined in 10.2.1 */
+		.blocklen_bytes = 16,
+		.cra_name = "ctr_aes192",
+		.backend_cra_name = "aes",
+	}, {
+		.flags = DRBG_CTR | DRBG_STRENGTH256,
+		.statelen = 48, /* 384 bits as defined in 10.2.1 */
+		.blocklen_bytes = 16,
+		.cra_name = "ctr_aes256",
+		.backend_cra_name = "aes",
+	},
+#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
+	{
+		.flags = DRBG_HMAC | DRBG_STRENGTH128,
+		.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 */
+};
+
+static int drbg_uninstantiate(struct drbg_state *drbg);
+
+/******************************************************************
+ * 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 for the noise source
+ * The test is performed on the noise source input data. Thus, the function
+ * implicitly knows the size of the buffer to be equal to the security
+ * strength.
+ *
+ * Note, this function disregards the nonce trailing the entropy data during
+ * initial seeding.
+ *
+ * drbg->drbg_mutex must have been taken.
+ *
+ * @drbg DRBG handle
+ * @entropy buffer of seed data to be checked
+ *
+ * return:
+ *	0 on success
+ *	-EAGAIN on when the CTRNG is not yet primed
+ *	< 0 on error
+ */
+static int drbg_fips_continuous_test(struct drbg_state *drbg,
+				     const unsigned char *entropy)
+{
+	unsigned short entropylen = drbg_sec_strength(drbg->core->flags);
+	int ret = 0;
+
+	if (!IS_ENABLED(CONFIG_CRYPTO_FIPS))
+		return 0;
+
+	/* skip test if we test the overall system */
+	if (list_empty(&drbg->test_data.list))
+		return 0;
+	/* only perform test in FIPS mode */
+	if (!fips_enabled)
+		return 0;
+
+	if (!drbg->fips_primed) {
+		/* Priming of FIPS test */
+		memcpy(drbg->prev, entropy, entropylen);
+		drbg->fips_primed = true;
+		/* priming: another round is needed */
+		return -EAGAIN;
+	}
+	ret = memcmp(drbg->prev, entropy, entropylen);
+	if (!ret)
+		panic("DRBG continuous self test failed\n");
+	memcpy(drbg->prev, entropy, entropylen);
+
+	/* the test shall pass when the two values are not equal */
+	return 0;
+}
+
+/*
+ * Convert an integer into a byte representation of this integer.
+ * The byte representation is big-endian
+ *
+ * @val value to be converted
+ * @buf buffer holding the converted integer -- caller must ensure that
+ *      buffer size is at least 32 bit
+ */
+#if (defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR))
+static inline void drbg_cpu_to_be32(__u32 val, unsigned char *buf)
+{
+	struct s {
+		__be32 conv;
+	};
+	struct s *conversion = (struct s *) buf;
+
+	conversion->conv = cpu_to_be32(val);
+}
+#endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */
+
+/******************************************************************
+ * CTR DRBG callback functions
+ ******************************************************************/
+
+#ifdef CONFIG_CRYPTO_DRBG_CTR
+#define CRYPTO_DRBG_CTR_STRING "CTR "
+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");
+
+static void drbg_kcapi_symsetkey(struct drbg_state *drbg,
+				 const unsigned char *key);
+static int drbg_kcapi_sym(struct drbg_state *drbg, 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);
+static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
+			      u8 *inbuf, u32 inbuflen,
+			      u8 *outbuf, u32 outlen);
+#define DRBG_OUTSCRATCHLEN 256
+
+/* 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,
+			struct list_head *in)
+{
+	int ret = 0;
+	struct drbg_string *curr = NULL;
+	struct drbg_string data;
+	short cnt = 0;
+
+	drbg_string_fill(&data, out, drbg_blocklen(drbg));
+
+	/* 10.4.3 step 2 / 4 */
+	drbg_kcapi_symsetkey(drbg, key);
+	list_for_each_entry(curr, in, list) {
+		const unsigned char *pos = curr->buf;
+		size_t len = curr->len;
+		/* 10.4.3 step 4.1 */
+		while (len) {
+			/* 10.4.3 step 4.2 */
+			if (drbg_blocklen(drbg) == cnt) {
+				cnt = 0;
+				ret = drbg_kcapi_sym(drbg, out, &data);
+				if (ret)
+					return ret;
+			}
+			out[cnt] ^= *pos;
+			pos++;
+			cnt++;
+			len--;
+		}
+	}
+	/* 10.4.3 step 4.2 for last block */
+	if (cnt)
+		ret = drbg_kcapi_sym(drbg, out, &data);
+
+	return ret;
+}
+
+/*
+ * 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)
+ *		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.
+ */
+
+/* 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,
+		       struct list_head *seedlist)
+{
+	int ret = -EFAULT;
+	unsigned char L_N[8];
+	/* S3 is input */
+	struct drbg_string S1, S2, S4, cipherin;
+	LIST_HEAD(bcc_list);
+	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;
+	struct drbg_string *seed = NULL;
+
+	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 */
+	list_for_each_entry(seed, seedlist, list)
+		inputlen += seed->len;
+	drbg_cpu_to_be32(inputlen, &L_N[0]);
+
+	/* 10.4.2 step 3 */
+	drbg_cpu_to_be32(bytes_to_return, &L_N[4]);
+
+	/* 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));
+	list_add_tail(&S1.list, &bcc_list);
+	drbg_string_fill(&S2, L_N, sizeof(L_N));
+	list_add_tail(&S2.list, &bcc_list);
+	list_splice_tail(seedlist, &bcc_list);
+	drbg_string_fill(&S4, pad, padlen);
+	list_add_tail(&S4.list, &bcc_list);
+
+	/* 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
+		 */
+		drbg_cpu_to_be32(i, iv);
+		/* 10.4.2 step 9.2 -- BCC and concatenation with temp */
+		ret = drbg_ctr_bcc(drbg, temp + templen, K, &bcc_list);
+		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 */
+	drbg_kcapi_symsetkey(drbg, temp);
+	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, 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:
+	memset(iv, 0, drbg_blocklen(drbg));
+	memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
+	memset(pad, 0, drbg_blocklen(drbg));
+	return ret;
+}
+
+/*
+ * 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.
+ */
+static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed,
+			   int reseed)
+{
+	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);
+
+	if (3 > reseed)
+		memset(df_data, 0, drbg_statelen(drbg));
+
+	if (!reseed) {
+		/*
+		 * The DRBG uses the CTR mode of the underlying AES cipher. The
+		 * CTR mode increments the counter value after the AES operation
+		 * but SP800-90A requires that the counter is incremented before
+		 * the AES operation. Hence, we increment it at the time we set
+		 * it by one.
+		 */
+		crypto_inc(drbg->V, drbg_blocklen(drbg));
+
+		ret = crypto_skcipher_setkey(drbg->ctr_handle, drbg->C,
+					     drbg_keylen(drbg));
+		if (ret)
+			goto out;
+	}
+
+	/* 10.2.1.3.2 step 2 and 10.2.1.4.2 step 2 */
+	if (seed) {
+		ret = drbg_ctr_df(drbg, df_data, drbg_statelen(drbg), seed);
+		if (ret)
+			goto out;
+	}
+
+	ret = drbg_kcapi_sym_ctr(drbg, df_data, drbg_statelen(drbg),
+				 temp, drbg_statelen(drbg));
+	if (ret)
+		return ret;
+
+	/* 10.2.1.2 step 5 */
+	ret = crypto_skcipher_setkey(drbg->ctr_handle, temp,
+				     drbg_keylen(drbg));
+	if (ret)
+		goto out;
+	/* 10.2.1.2 step 6 */
+	memcpy(drbg->V, temp + drbg_keylen(drbg), drbg_blocklen(drbg));
+	/* See above: increment counter by one to compensate timing of CTR op */
+	crypto_inc(drbg->V, drbg_blocklen(drbg));
+	ret = 0;
+
+out:
+	memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));
+	if (2 != reseed)
+		memset(df_data, 0, drbg_statelen(drbg));
+	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,
+			     struct list_head *addtl)
+{
+	int ret;
+	int len = min_t(int, buflen, INT_MAX);
+
+	/* 10.2.1.5.2 step 2 */
+	if (addtl && !list_empty(addtl)) {
+		ret = drbg_ctr_update(drbg, addtl, 2);
+		if (ret)
+			return 0;
+	}
+
+	/* 10.2.1.5.2 step 4.1 */
+	ret = drbg_kcapi_sym_ctr(drbg, NULL, 0, buf, len);
+	if (ret)
+		return ret;
+
+	/* 10.2.1.5.2 step 6 */
+	ret = drbg_ctr_update(drbg, NULL, 3);
+	if (ret)
+		len = ret;
+
+	return len;
+}
+
+static const 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, unsigned char *outval,
+			   const struct list_head *in);
+static void drbg_kcapi_hmacsetkey(struct drbg_state *drbg,
+				  const unsigned char *key);
+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
+#define CRYPTO_DRBG_HMAC_STRING "HMAC "
+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");
+
+/* update function of HMAC DRBG as defined in 10.1.2.2 */
+static int drbg_hmac_update(struct drbg_state *drbg, struct list_head *seed,
+			    int reseed)
+{
+	int ret = -EFAULT;
+	int i = 0;
+	struct drbg_string seed1, seed2, vdata;
+	LIST_HEAD(seedlist);
+	LIST_HEAD(vdatalist);
+
+	if (!reseed) {
+		/* 10.1.2.3 step 2 -- memset(0) of C is implicit with kzalloc */
+		memset(drbg->V, 1, drbg_statelen(drbg));
+		drbg_kcapi_hmacsetkey(drbg, drbg->C);
+	}
+
+	drbg_string_fill(&seed1, drbg->V, drbg_statelen(drbg));
+	list_add_tail(&seed1.list, &seedlist);
+	/* buffer of seed2 will be filled in for loop below with one byte */
+	drbg_string_fill(&seed2, NULL, 1);
+	list_add_tail(&seed2.list, &seedlist);
+	/* input data of seed is allowed to be NULL at this point */
+	if (seed)
+		list_splice_tail(seed, &seedlist);
+
+	drbg_string_fill(&vdata, drbg->V, drbg_statelen(drbg));
+	list_add_tail(&vdata.list, &vdatalist);
+	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;
+		ret = drbg_kcapi_hash(drbg, drbg->C, &seedlist);
+		if (ret)
+			return ret;
+		drbg_kcapi_hmacsetkey(drbg, drbg->C);
+
+		/* 10.1.2.2 step 2 and 5 -- HMAC for V */
+		ret = drbg_kcapi_hash(drbg, drbg->V, &vdatalist);
+		if (ret)
+			return ret;
+
+		/* 10.1.2.2 step 3 */
+		if (!seed)
+			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,
+			      struct list_head *addtl)
+{
+	int len = 0;
+	int ret = 0;
+	struct drbg_string data;
+	LIST_HEAD(datalist);
+
+	/* 10.1.2.5 step 2 */
+	if (addtl && !list_empty(addtl)) {
+		ret = drbg_hmac_update(drbg, addtl, 1);
+		if (ret)
+			return ret;
+	}
+
+	drbg_string_fill(&data, drbg->V, drbg_statelen(drbg));
+	list_add_tail(&data.list, &datalist);
+	while (len < buflen) {
+		unsigned int outlen = 0;
+		/* 10.1.2.5 step 4.1 */
+		ret = drbg_kcapi_hash(drbg, drbg->V, &datalist);
+		if (ret)
+			return ret;
+		outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
+			  drbg_blocklen(drbg) : (buflen - len);
+
+		/* 10.1.2.5 step 4.2 */
+		memcpy(buf + len, drbg->V, outlen);
+		len += outlen;
+	}
+
+	/* 10.1.2.5 step 6 */
+	if (addtl && !list_empty(addtl))
+		ret = drbg_hmac_update(drbg, addtl, 1);
+	else
+		ret = drbg_hmac_update(drbg, NULL, 1);
+	if (ret)
+		return ret;
+
+	return len;
+}
+
+static const 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
+#define CRYPTO_DRBG_HASH_STRING "HASH "
+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");
+
+/*
+ * 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--;
+	}
+}
+
+/*
+ * 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,
+			struct list_head *entropylist)
+{
+	int ret = 0;
+	size_t len = 0;
+	unsigned char input[5];
+	unsigned char *tmp = drbg->scratchpad + drbg_statelen(drbg);
+	struct drbg_string data;
+
+	/* 10.4.1 step 3 */
+	input[0] = 1;
+	drbg_cpu_to_be32((outlen * 8), &input[1]);
+
+	/* 10.4.1 step 4.1 -- concatenation of data for input into hash */
+	drbg_string_fill(&data, input, 5);
+	list_add(&data.list, entropylist);
+
+	/* 10.4.1 step 4 */
+	while (len < outlen) {
+		short blocklen = 0;
+		/* 10.4.1 step 4.1 */
+		ret = drbg_kcapi_hash(drbg, tmp, entropylist);
+		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:
+	memset(tmp, 0, drbg_blocklen(drbg));
+	return ret;
+}
+
+/* update function for Hash DRBG as defined in 10.1.1.2 / 10.1.1.3 */
+static int drbg_hash_update(struct drbg_state *drbg, struct list_head *seed,
+			    int reseed)
+{
+	int ret = 0;
+	struct drbg_string data1, data2;
+	LIST_HEAD(datalist);
+	LIST_HEAD(datalist2);
+	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);
+		list_add_tail(&data1.list, &datalist);
+		drbg_string_fill(&data2, V, drbg_statelen(drbg));
+		list_add_tail(&data2.list, &datalist);
+	}
+	list_splice_tail(seed, &datalist);
+
+	/* 10.1.1.2 / 10.1.1.3 step 2 and 3 */
+	ret = drbg_hash_df(drbg, drbg->V, drbg_statelen(drbg), &datalist);
+	if (ret)
+		goto out;
+
+	/* 10.1.1.2 / 10.1.1.3 step 4  */
+	prefix = DRBG_PREFIX0;
+	drbg_string_fill(&data1, &prefix, 1);
+	list_add_tail(&data1.list, &datalist2);
+	drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
+	list_add_tail(&data2.list, &datalist2);
+	/* 10.1.1.2 / 10.1.1.3 step 4 */
+	ret = drbg_hash_df(drbg, drbg->C, drbg_statelen(drbg), &datalist2);
+
+out:
+	memset(drbg->scratchpad, 0, drbg_statelen(drbg));
+	return ret;
+}
+
+/* processing of additional information string for Hash DRBG */
+static int drbg_hash_process_addtl(struct drbg_state *drbg,
+				   struct list_head *addtl)
+{
+	int ret = 0;
+	struct drbg_string data1, data2;
+	LIST_HEAD(datalist);
+	unsigned char prefix = DRBG_PREFIX2;
+
+	/* 10.1.1.4 step 2 */
+	if (!addtl || list_empty(addtl))
+		return 0;
+
+	/* 10.1.1.4 step 2a */
+	drbg_string_fill(&data1, &prefix, 1);
+	drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
+	list_add_tail(&data1.list, &datalist);
+	list_add_tail(&data2.list, &datalist);
+	list_splice_tail(addtl, &datalist);
+	ret = drbg_kcapi_hash(drbg, drbg->scratchpad, &datalist);
+	if (ret)
+		goto out;
+
+	/* 10.1.1.4 step 2b */
+	drbg_add_buf(drbg->V, drbg_statelen(drbg),
+		     drbg->scratchpad, drbg_blocklen(drbg));
+
+out:
+	memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
+	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;
+	LIST_HEAD(datalist);
+
+	/* 10.1.1.4 step hashgen 2 */
+	memcpy(src, drbg->V, drbg_statelen(drbg));
+
+	drbg_string_fill(&data, src, drbg_statelen(drbg));
+	list_add_tail(&data.list, &datalist);
+	while (len < buflen) {
+		unsigned int outlen = 0;
+		/* 10.1.1.4 step hashgen 4.1 */
+		ret = drbg_kcapi_hash(drbg, dst, &datalist);
+		if (ret) {
+			len = ret;
+			goto out;
+		}
+		outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
+			  drbg_blocklen(drbg) : (buflen - len);
+		/* 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)
+			crypto_inc(src, drbg_statelen(drbg));
+	}
+
+out:
+	memset(drbg->scratchpad, 0,
+	       (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,
+			      struct list_head *addtl)
+{
+	int len = 0;
+	int ret = 0;
+	union {
+		unsigned char req[8];
+		__be64 req_int;
+	} u;
+	unsigned char prefix = DRBG_PREFIX3;
+	struct drbg_string data1, data2;
+	LIST_HEAD(datalist);
+
+	/* 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);
+	list_add_tail(&data1.list, &datalist);
+	drbg_string_fill(&data2, drbg->V, drbg_statelen(drbg));
+	list_add_tail(&data2.list, &datalist);
+	ret = drbg_kcapi_hash(drbg, drbg->scratchpad, &datalist);
+	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));
+	u.req_int = cpu_to_be64(drbg->reseed_ctr);
+	drbg_add_buf(drbg->V, drbg_statelen(drbg), u.req, 8);
+
+out:
+	memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
+	return len;
+}
+
+/*
+ * scratchpad usage: as update and generate are used isolated, both
+ * can use the scratchpad
+ */
+static const 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
+ ******************************************************************/
+
+static inline int __drbg_seed(struct drbg_state *drbg, struct list_head *seed,
+			      int reseed, enum drbg_seed_state new_seed_state)
+{
+	int ret = drbg->d_ops->update(drbg, seed, reseed);
+
+	if (ret)
+		return ret;
+
+	drbg->seeded = new_seed_state;
+	/* 10.1.1.2 / 10.1.1.3 step 5 */
+	drbg->reseed_ctr = 1;
+
+	switch (drbg->seeded) {
+	case DRBG_SEED_STATE_UNSEEDED:
+		/* Impossible, but handle it to silence compiler warnings. */
+	case DRBG_SEED_STATE_PARTIAL:
+		/*
+		 * Require frequent reseeds until the seed source is
+		 * fully initialized.
+		 */
+		drbg->reseed_threshold = 50;
+		break;
+
+	case DRBG_SEED_STATE_FULL:
+		/*
+		 * Seed source has become fully initialized, frequent
+		 * reseeds no longer required.
+		 */
+		drbg->reseed_threshold = drbg_max_requests(drbg);
+		break;
+	}
+
+	return ret;
+}
+
+static inline int drbg_get_random_bytes(struct drbg_state *drbg,
+					unsigned char *entropy,
+					unsigned int entropylen)
+{
+	int ret;
+
+	do {
+		get_random_bytes(entropy, entropylen);
+		ret = drbg_fips_continuous_test(drbg, entropy);
+		if (ret && ret != -EAGAIN)
+			return ret;
+	} while (ret);
+
+	return 0;
+}
+
+static int drbg_seed_from_random(struct drbg_state *drbg)
+{
+	struct drbg_string data;
+	LIST_HEAD(seedlist);
+	unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
+	unsigned char entropy[32];
+	int ret;
+
+	BUG_ON(!entropylen);
+	BUG_ON(entropylen > sizeof(entropy));
+
+	drbg_string_fill(&data, entropy, entropylen);
+	list_add_tail(&data.list, &seedlist);
+
+	ret = drbg_get_random_bytes(drbg, entropy, entropylen);
+	if (ret)
+		goto out;
+
+	ret = __drbg_seed(drbg, &seedlist, true, DRBG_SEED_STATE_FULL);
+
+out:
+	memzero_explicit(entropy, entropylen);
+	return ret;
+}
+
+/*
+ * 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)
+{
+	int ret;
+	unsigned char entropy[((32 + 16) * 2)];
+	unsigned int entropylen = drbg_sec_strength(drbg->core->flags);
+	struct drbg_string data1;
+	LIST_HEAD(seedlist);
+	enum drbg_seed_state new_seed_state = DRBG_SEED_STATE_FULL;
+
+	/* 9.1 / 9.2 / 9.3.1 step 3 */
+	if (pers && pers->len > (drbg_max_addtl(drbg))) {
+		pr_devel("DRBG: personalization string too long %zu\n",
+			 pers->len);
+		return -EINVAL;
+	}
+
+	if (list_empty(&drbg->test_data.list)) {
+		drbg_string_fill(&data1, drbg->test_data.buf,
+				 drbg->test_data.len);
+		pr_devel("DRBG: using test entropy\n");
+	} else {
+		/*
+		 * 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));
+
+		/* Get seed from in-kernel /dev/urandom */
+		if (!rng_is_initialized())
+			new_seed_state = DRBG_SEED_STATE_PARTIAL;
+
+		ret = drbg_get_random_bytes(drbg, entropy, entropylen);
+		if (ret)
+			goto out;
+
+		if (!drbg->jent) {
+			drbg_string_fill(&data1, entropy, entropylen);
+			pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
+				 entropylen);
+		} else {
+			/* 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);
+
+				/*
+				 * Do not treat the transient failure of the
+				 * Jitter RNG as an error that needs to be
+				 * reported. The combined number of the
+				 * maximum reseed threshold times the maximum
+				 * number of Jitter RNG transient errors is
+				 * less than the reseed threshold required by
+				 * SP800-90A allowing us to treat the
+				 * transient errors as such.
+				 *
+				 * However, we mandate that at least the first
+				 * seeding operation must succeed with the
+				 * Jitter RNG.
+				 */
+				if (!reseed || ret != -EAGAIN)
+					goto out;
+			}
+
+			drbg_string_fill(&data1, entropy, entropylen * 2);
+			pr_devel("DRBG: (re)seeding with %u bytes of entropy\n",
+				 entropylen * 2);
+		}
+	}
+	list_add_tail(&data1.list, &seedlist);
+
+	/*
+	 * 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
+	 */
+	if (pers && pers->buf && 0 < pers->len) {
+		list_add_tail(&pers->list, &seedlist);
+		pr_devel("DRBG: using personalization string\n");
+	}
+
+	if (!reseed) {
+		memset(drbg->V, 0, drbg_statelen(drbg));
+		memset(drbg->C, 0, drbg_statelen(drbg));
+	}
+
+	ret = __drbg_seed(drbg, &seedlist, reseed, new_seed_state);
+
+out:
+	memzero_explicit(entropy, entropylen * 2);
+
+	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;
+	kzfree(drbg->Vbuf);
+	drbg->Vbuf = NULL;
+	drbg->V = NULL;
+	kzfree(drbg->Cbuf);
+	drbg->Cbuf = NULL;
+	drbg->C = NULL;
+	kzfree(drbg->scratchpadbuf);
+	drbg->scratchpadbuf = NULL;
+	drbg->reseed_ctr = 0;
+	drbg->d_ops = NULL;
+	drbg->core = NULL;
+	if (IS_ENABLED(CONFIG_CRYPTO_FIPS)) {
+		kzfree(drbg->prev);
+		drbg->prev = NULL;
+		drbg->fips_primed = false;
+	}
+}
+
+/*
+ * 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;
+
+	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;
+	}
+
+	ret = drbg->d_ops->crypto_init(drbg);
+	if (ret < 0)
+		goto err;
+
+	drbg->Vbuf = kmalloc(drbg_statelen(drbg) + ret, GFP_KERNEL);
+	if (!drbg->Vbuf) {
+		ret = -ENOMEM;
+		goto fini;
+	}
+	drbg->V = PTR_ALIGN(drbg->Vbuf, ret + 1);
+	drbg->Cbuf = kmalloc(drbg_statelen(drbg) + ret, GFP_KERNEL);
+	if (!drbg->Cbuf) {
+		ret = -ENOMEM;
+		goto fini;
+	}
+	drbg->C = PTR_ALIGN(drbg->Cbuf, ret + 1);
+	/* 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 */
+			  drbg_statelen(drbg) + drbg_blocklen(drbg); /* temp */
+	else
+		sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg);
+
+	if (0 < sb_size) {
+		drbg->scratchpadbuf = kzalloc(sb_size + ret, GFP_KERNEL);
+		if (!drbg->scratchpadbuf) {
+			ret = -ENOMEM;
+			goto fini;
+		}
+		drbg->scratchpad = PTR_ALIGN(drbg->scratchpadbuf, ret + 1);
+	}
+
+	if (IS_ENABLED(CONFIG_CRYPTO_FIPS)) {
+		drbg->prev = kzalloc(drbg_sec_strength(drbg->core->flags),
+				     GFP_KERNEL);
+		if (!drbg->prev)
+			goto fini;
+		drbg->fips_primed = false;
+	}
+
+	return 0;
+
+fini:
+	drbg->d_ops->crypto_fini(drbg);
+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.
+ *
+ * return: 0 when all bytes are generated; < 0 in case of an error
+ */
+static int drbg_generate(struct drbg_state *drbg,
+			 unsigned char *buf, unsigned int buflen,
+			 struct drbg_string *addtl)
+{
+	int len = 0;
+	LIST_HEAD(addtllist);
+
+	if (!drbg->core) {
+		pr_devel("DRBG: not yet seeded\n");
+		return -EINVAL;
+	}
+	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;
+	if (buflen > (drbg_max_request_bytes(drbg))) {
+		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 */
+	if (addtl && addtl->len > (drbg_max_addtl(drbg))) {
+		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.
+	 */
+	if (drbg->reseed_threshold < drbg->reseed_ctr)
+		drbg->seeded = DRBG_SEED_STATE_UNSEEDED;
+
+	if (drbg->pr || drbg->seeded == DRBG_SEED_STATE_UNSEEDED) {
+		pr_devel("DRBG: reseeding before generation (prediction "
+			 "resistance: %s, state %s)\n",
+			 drbg->pr ? "true" : "false",
+			 (drbg->seeded ==  DRBG_SEED_STATE_FULL ?
+			  "seeded" : "unseeded"));
+		/* 9.3.1 steps 7.1 through 7.3 */
+		len = drbg_seed(drbg, addtl, true);
+		if (len)
+			goto err;
+		/* 9.3.1 step 7.4 */
+		addtl = NULL;
+	} else if (rng_is_initialized() &&
+		   drbg->seeded == DRBG_SEED_STATE_PARTIAL) {
+		len = drbg_seed_from_random(drbg);
+		if (len)
+			goto err;
+	}
+
+	if (addtl && 0 < addtl->len)
+		list_add_tail(&addtl->list, &addtllist);
+	/* 9.3.1 step 8 and 10 */
+	len = drbg->d_ops->generate(drbg, buf, buflen, &addtllist);
+
+	/* 10.1.1.4 step 6, 10.1.2.5 step 7, 10.2.1.5.2 step 7 */
+	drbg->reseed_ctr++;
+	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
+	if (drbg->reseed_ctr && !(drbg->reseed_ctr % 4096)) {
+		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
+
+	/*
+	 * All operations were successful, return 0 as mandated by
+	 * the kernel crypto API interface.
+	 */
+	len = 0;
+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)
+{
+	unsigned int len = 0;
+	unsigned int slice = 0;
+	do {
+		int err = 0;
+		unsigned int chunk = 0;
+		slice = ((buflen - len) / drbg_max_request_bytes(drbg));
+		chunk = slice ? drbg_max_request_bytes(drbg) : (buflen - len);
+		mutex_lock(&drbg->drbg_mutex);
+		err = drbg_generate(drbg, buf + len, chunk, addtl);
+		mutex_unlock(&drbg->drbg_mutex);
+		if (0 > err)
+			return err;
+		len += chunk;
+	} while (slice > 0 && (len < buflen));
+	return 0;
+}
+
+static int drbg_prepare_hrng(struct drbg_state *drbg)
+{
+	/* We do not need an HRNG in test mode. */
+	if (list_empty(&drbg->test_data.list))
+		return 0;
+
+	drbg->jent = crypto_alloc_rng("jitterentropy_rng", 0, 0);
+
+	return 0;
+}
+
+/*
+ * 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)
+{
+	int ret;
+	bool reseed = true;
+
+	pr_devel("DRBG: Initializing DRBG core %d with prediction resistance "
+		 "%s\n", coreref, pr ? "enabled" : "disabled");
+	mutex_lock(&drbg->drbg_mutex);
+
+	/* 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 */
+
+	if (!drbg->core) {
+		drbg->core = &drbg_cores[coreref];
+		drbg->pr = pr;
+		drbg->seeded = DRBG_SEED_STATE_UNSEEDED;
+		drbg->reseed_threshold = drbg_max_requests(drbg);
+
+		ret = drbg_alloc_state(drbg);
+		if (ret)
+			goto unlock;
+
+		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");
+		}
+
+		reseed = false;
+	}
+
+	ret = drbg_seed(drbg, pers, reseed);
+
+	if (ret && !reseed)
+		goto free_everything;
+
+	mutex_unlock(&drbg->drbg_mutex);
+	return ret;
+
+unlock:
+	mutex_unlock(&drbg->drbg_mutex);
+	return ret;
+
+free_everything:
+	mutex_unlock(&drbg->drbg_mutex);
+	drbg_uninstantiate(drbg);
+	return ret;
+}
+
+/*
+ * 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)
+{
+	if (!IS_ERR_OR_NULL(drbg->jent))
+		crypto_free_rng(drbg->jent);
+	drbg->jent = NULL;
+
+	if (drbg->d_ops)
+		drbg->d_ops->crypto_fini(drbg);
+	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
+ * @data test data
+ * @len test data length
+ */
+static void drbg_kcapi_set_entropy(struct crypto_rng *tfm,
+				   const u8 *data, unsigned int len)
+{
+	struct drbg_state *drbg = crypto_rng_ctx(tfm);
+
+	mutex_lock(&drbg->drbg_mutex);
+	drbg_string_fill(&drbg->test_data, data, len);
+	mutex_unlock(&drbg->drbg_mutex);
+}
+
+/***************************************************************
+ * 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)) {
+		pr_info("DRBG: could not allocate digest TFM handle: %s\n",
+				drbg->core->backend_cra_name);
+		return PTR_ERR(tfm);
+	}
+	BUG_ON(drbg_blocklen(drbg) != crypto_shash_digestsize(tfm));
+	sdesc = kzalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm),
+			GFP_KERNEL);
+	if (!sdesc) {
+		crypto_free_shash(tfm);
+		return -ENOMEM;
+	}
+
+	sdesc->shash.tfm = tfm;
+	sdesc->shash.flags = 0;
+	drbg->priv_data = sdesc;
+
+	return crypto_shash_alignmask(tfm);
+}
+
+static int drbg_fini_hash_kernel(struct drbg_state *drbg)
+{
+	struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
+	if (sdesc) {
+		crypto_free_shash(sdesc->shash.tfm);
+		kzfree(sdesc);
+	}
+	drbg->priv_data = NULL;
+	return 0;
+}
+
+static void drbg_kcapi_hmacsetkey(struct drbg_state *drbg,
+				  const unsigned char *key)
+{
+	struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
+
+	crypto_shash_setkey(sdesc->shash.tfm, key, drbg_statelen(drbg));
+}
+
+static int drbg_kcapi_hash(struct drbg_state *drbg, unsigned char *outval,
+			   const struct list_head *in)
+{
+	struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
+	struct drbg_string *input = NULL;
+
+	crypto_shash_init(&sdesc->shash);
+	list_for_each_entry(input, in, list)
+		crypto_shash_update(&sdesc->shash, input->buf, input->len);
+	return crypto_shash_final(&sdesc->shash, outval);
+}
+#endif /* (CONFIG_CRYPTO_DRBG_HASH || CONFIG_CRYPTO_DRBG_HMAC) */
+
+#ifdef CONFIG_CRYPTO_DRBG_CTR
+static int drbg_fini_sym_kernel(struct drbg_state *drbg)
+{
+	struct crypto_cipher *tfm =
+		(struct crypto_cipher *)drbg->priv_data;
+	if (tfm)
+		crypto_free_cipher(tfm);
+	drbg->priv_data = NULL;
+
+	if (drbg->ctr_handle)
+		crypto_free_skcipher(drbg->ctr_handle);
+	drbg->ctr_handle = NULL;
+
+	if (drbg->ctr_req)
+		skcipher_request_free(drbg->ctr_req);
+	drbg->ctr_req = NULL;
+
+	kfree(drbg->outscratchpadbuf);
+	drbg->outscratchpadbuf = NULL;
+
+	return 0;
+}
+
+static int drbg_init_sym_kernel(struct drbg_state *drbg)
+{
+	struct crypto_cipher *tfm;
+	struct crypto_skcipher *sk_tfm;
+	struct skcipher_request *req;
+	unsigned int alignmask;
+	char ctr_name[CRYPTO_MAX_ALG_NAME];
+
+	tfm = crypto_alloc_cipher(drbg->core->backend_cra_name, 0, 0);
+	if (IS_ERR(tfm)) {
+		pr_info("DRBG: could not allocate cipher TFM handle: %s\n",
+				drbg->core->backend_cra_name);
+		return PTR_ERR(tfm);
+	}
+	BUG_ON(drbg_blocklen(drbg) != crypto_cipher_blocksize(tfm));
+	drbg->priv_data = tfm;
+
+	if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)",
+	    drbg->core->backend_cra_name) >= CRYPTO_MAX_ALG_NAME) {
+		drbg_fini_sym_kernel(drbg);
+		return -EINVAL;
+	}
+	sk_tfm = crypto_alloc_skcipher(ctr_name, 0, 0);
+	if (IS_ERR(sk_tfm)) {
+		pr_info("DRBG: could not allocate CTR cipher TFM handle: %s\n",
+				ctr_name);
+		drbg_fini_sym_kernel(drbg);
+		return PTR_ERR(sk_tfm);
+	}
+	drbg->ctr_handle = sk_tfm;
+	crypto_init_wait(&drbg->ctr_wait);
+
+	req = skcipher_request_alloc(sk_tfm, GFP_KERNEL);
+	if (!req) {
+		pr_info("DRBG: could not allocate request queue\n");
+		drbg_fini_sym_kernel(drbg);
+		return -ENOMEM;
+	}
+	drbg->ctr_req = req;
+	skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
+						CRYPTO_TFM_REQ_MAY_SLEEP,
+					crypto_req_done, &drbg->ctr_wait);
+
+	alignmask = crypto_skcipher_alignmask(sk_tfm);
+	drbg->outscratchpadbuf = kmalloc(DRBG_OUTSCRATCHLEN + alignmask,
+					 GFP_KERNEL);
+	if (!drbg->outscratchpadbuf) {
+		drbg_fini_sym_kernel(drbg);
+		return -ENOMEM;
+	}
+	drbg->outscratchpad = (u8 *)PTR_ALIGN(drbg->outscratchpadbuf,
+					      alignmask + 1);
+
+	sg_init_table(&drbg->sg_in, 1);
+	sg_init_one(&drbg->sg_out, drbg->outscratchpad, DRBG_OUTSCRATCHLEN);
+
+	return alignmask;
+}
+
+static void drbg_kcapi_symsetkey(struct drbg_state *drbg,
+				 const unsigned char *key)
+{
+	struct crypto_cipher *tfm =
+		(struct crypto_cipher *)drbg->priv_data;
+
+	crypto_cipher_setkey(tfm, key, (drbg_keylen(drbg)));
+}
+
+static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval,
+			  const struct drbg_string *in)
+{
+	struct crypto_cipher *tfm =
+		(struct crypto_cipher *)drbg->priv_data;
+
+	/* there is only component in *in */
+	BUG_ON(in->len < drbg_blocklen(drbg));
+	crypto_cipher_encrypt_one(tfm, outval, in->buf);
+	return 0;
+}
+
+static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
+			      u8 *inbuf, u32 inlen,
+			      u8 *outbuf, u32 outlen)
+{
+	struct scatterlist *sg_in = &drbg->sg_in, *sg_out = &drbg->sg_out;
+	u32 scratchpad_use = min_t(u32, outlen, DRBG_OUTSCRATCHLEN);
+	int ret;
+
+	if (inbuf) {
+		/* Use caller-provided input buffer */
+		sg_set_buf(sg_in, inbuf, inlen);
+	} else {
+		/* Use scratchpad for in-place operation */
+		inlen = scratchpad_use;
+		memset(drbg->outscratchpad, 0, scratchpad_use);
+		sg_set_buf(sg_in, drbg->outscratchpad, scratchpad_use);
+	}
+
+	while (outlen) {
+		u32 cryptlen = min3(inlen, outlen, (u32)DRBG_OUTSCRATCHLEN);
+
+		/* Output buffer may not be valid for SGL, use scratchpad */
+		skcipher_request_set_crypt(drbg->ctr_req, sg_in, sg_out,
+					   cryptlen, drbg->V);
+		ret = crypto_wait_req(crypto_skcipher_encrypt(drbg->ctr_req),
+					&drbg->ctr_wait);
+		if (ret)
+			goto out;
+
+		crypto_init_wait(&drbg->ctr_wait);
+
+		memcpy(outbuf, drbg->outscratchpad, cryptlen);
+		memzero_explicit(drbg->outscratchpad, cryptlen);
+
+		outlen -= cryptlen;
+		outbuf += cryptlen;
+	}
+	ret = 0;
+
+out:
+	return ret;
+}
+#endif /* CONFIG_CRYPTO_DRBG_CTR */
+
+/***************************************************************
+ * Kernel crypto API interface to register DRBG
+ ***************************************************************/
+
+/*
+ * Look up the DRBG flags by given kernel crypto API cra_name
+ * The code uses the drbg_cores definition to do this
+ *
+ * @cra_name kernel crypto API cra_name
+ * @coreref reference to integer which is filled with the pointer to
+ *  the applicable core
+ * @pr reference for setting prediction resistance
+ *
+ * return: flags
+ */
+static inline void drbg_convert_tfm_core(const char *cra_driver_name,
+					 int *coreref, bool *pr)
+{
+	int i = 0;
+	size_t start = 0;
+	int len = 0;
+
+	*pr = true;
+	/* disassemble the names */
+	if (!memcmp(cra_driver_name, "drbg_nopr_", 10)) {
+		start = 10;
+		*pr = false;
+	} else if (!memcmp(cra_driver_name, "drbg_pr_", 8)) {
+		start = 8;
+	} else {
+		return;
+	}
+
+	/* remove the first part */
+	len = strlen(cra_driver_name) - start;
+	for (i = 0; ARRAY_SIZE(drbg_cores) > i; i++) {
+		if (!memcmp(cra_driver_name + start, drbg_cores[i].cra_name,
+			    len)) {
+			*coreref = i;
+			return;
+		}
+	}
+}
+
+static int drbg_kcapi_init(struct crypto_tfm *tfm)
+{
+	struct drbg_state *drbg = crypto_tfm_ctx(tfm);
+
+	mutex_init(&drbg->drbg_mutex);
+
+	return 0;
+}
+
+static void drbg_kcapi_cleanup(struct crypto_tfm *tfm)
+{
+	drbg_uninstantiate(crypto_tfm_ctx(tfm));
+}
+
+/*
+ * Generate random numbers invoked by the kernel crypto API:
+ * The API of the kernel crypto API is extended as follows:
+ *
+ * src is additional input supplied to the RNG.
+ * slen is the length of src.
+ * dst is the output buffer where random data is to be stored.
+ * dlen is the length of dst.
+ */
+static int drbg_kcapi_random(struct crypto_rng *tfm,
+			     const u8 *src, unsigned int slen,
+			     u8 *dst, unsigned int dlen)
+{
+	struct drbg_state *drbg = crypto_rng_ctx(tfm);
+	struct drbg_string *addtl = NULL;
+	struct drbg_string string;
+
+	if (slen) {
+		/* linked list variable is now local to allow modification */
+		drbg_string_fill(&string, src, slen);
+		addtl = &string;
+	}
+
+	return drbg_generate_long(drbg, dst, dlen, addtl);
+}
+
+/*
+ * Seed the DRBG invoked by the kernel crypto API
+ */
+static int drbg_kcapi_seed(struct crypto_rng *tfm,
+			   const u8 *seed, unsigned int slen)
+{
+	struct drbg_state *drbg = crypto_rng_ctx(tfm);
+	struct crypto_tfm *tfm_base = crypto_rng_tfm(tfm);
+	bool pr = false;
+	struct drbg_string string;
+	struct drbg_string *seed_string = NULL;
+	int coreref = 0;
+
+	drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base), &coreref,
+			      &pr);
+	if (0 < slen) {
+		drbg_string_fill(&string, seed, slen);
+		seed_string = &string;
+	}
+
+	return drbg_instantiate(drbg, seed_string, coreref, pr);
+}
+
+/***************************************************************
+ * Kernel module: code to load the module
+ ***************************************************************/
+
+/*
+ * Tests as defined in 11.3.2 in addition to the cipher tests: testing
+ * of the error handling.
+ *
+ * Note: testing of failing seed source as defined in 11.3.2 is not applicable
+ * as seed source of get_random_bytes does not fail.
+ *
+ * Note 2: There is no sensible way of testing the reseed counter
+ * enforcement, so skip it.
+ */
+static inline int __init drbg_healthcheck_sanity(void)
+{
+	int len = 0;
+#define OUTBUFLEN 16
+	unsigned char buf[OUTBUFLEN];
+	struct drbg_state *drbg = NULL;
+	int ret = -EFAULT;
+	int rc = -EFAULT;
+	bool pr = false;
+	int coreref = 0;
+	struct drbg_string addtl;
+	size_t max_addtllen, max_request_bytes;
+
+	/* only perform test in FIPS mode */
+	if (!fips_enabled)
+		return 0;
+
+#ifdef CONFIG_CRYPTO_DRBG_CTR
+	drbg_convert_tfm_core("drbg_nopr_ctr_aes128", &coreref, &pr);
+#elif defined CONFIG_CRYPTO_DRBG_HASH
+	drbg_convert_tfm_core("drbg_nopr_sha256", &coreref, &pr);
+#else
+	drbg_convert_tfm_core("drbg_nopr_hmac_sha256", &coreref, &pr);
+#endif
+
+	drbg = kzalloc(sizeof(struct drbg_state), GFP_KERNEL);
+	if (!drbg)
+		return -ENOMEM;
+
+	mutex_init(&drbg->drbg_mutex);
+	drbg->core = &drbg_cores[coreref];
+	drbg->reseed_threshold = drbg_max_requests(drbg);
+
+	/*
+	 * if the following tests fail, it is likely that there is a buffer
+	 * overflow as buf is much smaller than the requested or provided
+	 * string lengths -- in case the error handling does not succeed
+	 * we may get an OOPS. And we want to get an OOPS as this is a
+	 * grave bug.
+	 */
+
+	max_addtllen = drbg_max_addtl(drbg);
+	max_request_bytes = drbg_max_request_bytes(drbg);
+	drbg_string_fill(&addtl, buf, max_addtllen + 1);
+	/* overflow addtllen with additonal info string */
+	len = drbg_generate(drbg, buf, OUTBUFLEN, &addtl);
+	BUG_ON(0 < len);
+	/* overflow max_bits */
+	len = drbg_generate(drbg, buf, (max_request_bytes + 1), NULL);
+	BUG_ON(0 < len);
+
+	/* overflow max addtllen with personalization string */
+	ret = drbg_seed(drbg, &addtl, false);
+	BUG_ON(0 == ret);
+	/* all tests passed */
+	rc = 0;
+
+	pr_devel("DRBG: Sanity tests for failure code paths successfully "
+		 "completed\n");
+
+	kfree(drbg);
+	return rc;
+}
+
+static struct rng_alg drbg_algs[22];
+
+/*
+ * Fill the array drbg_algs used to register the different DRBGs
+ * with the kernel crypto API. To fill the array, the information
+ * from drbg_cores[] is used.
+ */
+static inline void __init drbg_fill_array(struct rng_alg *alg,
+					  const struct drbg_core *core, int pr)
+{
+	int pos = 0;
+	static int priority = 200;
+
+	memcpy(alg->base.cra_name, "stdrng", 6);
+	if (pr) {
+		memcpy(alg->base.cra_driver_name, "drbg_pr_", 8);
+		pos = 8;
+	} else {
+		memcpy(alg->base.cra_driver_name, "drbg_nopr_", 10);
+		pos = 10;
+	}
+	memcpy(alg->base.cra_driver_name + pos, core->cra_name,
+	       strlen(core->cra_name));
+
+	alg->base.cra_priority = priority;
+	priority++;
+	/*
+	 * If FIPS mode enabled, the selected DRBG shall have the
+	 * highest cra_priority over other stdrng instances to ensure
+	 * it is selected.
+	 */
+	if (fips_enabled)
+		alg->base.cra_priority += 200;
+
+	alg->base.cra_ctxsize 	= sizeof(struct drbg_state);
+	alg->base.cra_module	= THIS_MODULE;
+	alg->base.cra_init	= drbg_kcapi_init;
+	alg->base.cra_exit	= drbg_kcapi_cleanup;
+	alg->generate		= drbg_kcapi_random;
+	alg->seed		= drbg_kcapi_seed;
+	alg->set_ent		= drbg_kcapi_set_entropy;
+	alg->seedsize		= 0;
+}
+
+static int __init drbg_init(void)
+{
+	unsigned int i = 0; /* pointer to drbg_algs */
+	unsigned int j = 0; /* pointer to drbg_cores */
+	int ret;
+
+	ret = drbg_healthcheck_sanity();
+	if (ret)
+		return ret;
+
+	if (ARRAY_SIZE(drbg_cores) * 2 > ARRAY_SIZE(drbg_algs)) {
+		pr_info("DRBG: Cannot register all DRBG types"
+			"(slots needed: %zu, slots available: %zu)\n",
+			ARRAY_SIZE(drbg_cores) * 2, ARRAY_SIZE(drbg_algs));
+		return -EFAULT;
+	}
+
+	/*
+	 * each DRBG definition can be used with PR and without PR, thus
+	 * we instantiate each DRBG in drbg_cores[] twice.
+	 *
+	 * As the order of placing them into the drbg_algs array matters
+	 * (the later DRBGs receive a higher cra_priority) we register the
+	 * prediction resistance DRBGs first as the should not be too
+	 * interesting.
+	 */
+	for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
+		drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 1);
+	for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
+		drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 0);
+	return crypto_register_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
+}
+
+static void __exit drbg_exit(void)
+{
+	crypto_unregister_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
+}
+
+module_init(drbg_init);
+module_exit(drbg_exit);
+#ifndef CRYPTO_DRBG_HASH_STRING
+#define CRYPTO_DRBG_HASH_STRING ""
+#endif
+#ifndef CRYPTO_DRBG_HMAC_STRING
+#define CRYPTO_DRBG_HMAC_STRING ""
+#endif
+#ifndef CRYPTO_DRBG_CTR_STRING
+#define CRYPTO_DRBG_CTR_STRING ""
+#endif
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
+MODULE_DESCRIPTION("NIST SP800-90A Deterministic Random Bit Generator (DRBG) "
+		   "using following cores: "
+		   CRYPTO_DRBG_HASH_STRING
+		   CRYPTO_DRBG_HMAC_STRING
+		   CRYPTO_DRBG_CTR_STRING);
+MODULE_ALIAS_CRYPTO("stdrng");