Move tinycrypt function

components/bt/porting/ext/tinycrypt/src/hmac_prng.c

@@ -0,0 +1,212 @@
+/* hmac_prng.c - TinyCrypt implementation of HMAC-PRNG */
+
+/*
+ *  Copyright (C) 2017 by Intel Corporation, All Rights Reserved.
+ *
+ *  Redistribution and use in source and binary forms, with or without
+ *  modification, are permitted provided that the following conditions are met:
+ *
+ *    - Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *
+ *    - 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.
+ *
+ *    - Neither the name of Intel Corporation nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ *  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ *  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS 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 ADVISED OF THE
+ *  POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <tinycrypt/hmac_prng.h>
+#include <tinycrypt/hmac.h>
+#include <tinycrypt/constants.h>
+#include <tinycrypt/utils.h>
+
+/*
+ * min bytes in the seed string.
+ * MIN_SLEN*8 must be at least the expected security level.
+ */
+static const unsigned int MIN_SLEN = 32;
+
+/*
+ * max bytes in the seed string;
+ * SP800-90A specifies a maximum of 2^35 bits (i.e., 2^32 bytes).
+ */
+static const unsigned int MAX_SLEN = UINT32_MAX;
+
+/*
+ * max bytes in the personalization string;
+ * SP800-90A specifies a maximum of 2^35 bits (i.e., 2^32 bytes).
+ */
+static const unsigned int MAX_PLEN = UINT32_MAX;
+
+/*
+ * max bytes in the additional_info string;
+ * SP800-90A specifies a maximum of 2^35 bits (i.e., 2^32 bytes).
+ */
+static const unsigned int MAX_ALEN = UINT32_MAX;
+
+/*
+ * max number of generates between re-seeds;
+ * TinyCrypt accepts up to (2^32 - 1) which is the maximal value of
+ * a 32-bit unsigned int variable, while SP800-90A specifies a maximum of 2^48.
+ */
+static const unsigned int MAX_GENS = UINT32_MAX;
+
+/*
+ * maximum bytes per generate call;
+ * SP800-90A specifies a maximum up to 2^19.
+ */
+static const unsigned int  MAX_OUT = (1 << 19);
+
+/*
+ * Assumes: prng != NULL, e != NULL, len >= 0.
+ */
+static void update(TCHmacPrng_t prng, const uint8_t *e, unsigned int len)
+{
+	const uint8_t separator0 = 0x00;
+	const uint8_t separator1 = 0x01;
+
+	/* use current state, e and separator 0 to compute a new prng key: */
+	(void)tc_hmac_init(&prng->h);
+	(void)tc_hmac_update(&prng->h, prng->v, sizeof(prng->v));
+	(void)tc_hmac_update(&prng->h, &separator0, sizeof(separator0));
+	(void)tc_hmac_update(&prng->h, e, len);
+	(void)tc_hmac_final(prng->key, sizeof(prng->key), &prng->h);
+	/* configure the new prng key into the prng's instance of hmac */
+	(void)tc_hmac_set_key(&prng->h, prng->key, sizeof(prng->key));
+
+	/* use the new key to compute a new state variable v */
+	(void)tc_hmac_init(&prng->h);
+	(void)tc_hmac_update(&prng->h, prng->v, sizeof(prng->v));
+	(void)tc_hmac_final(prng->v, sizeof(prng->v), &prng->h);
+
+	/* use current state, e and separator 1 to compute a new prng key: */
+	(void)tc_hmac_init(&prng->h);
+	(void)tc_hmac_update(&prng->h, prng->v, sizeof(prng->v));
+	(void)tc_hmac_update(&prng->h, &separator1, sizeof(separator1));
+	(void)tc_hmac_update(&prng->h, e, len);
+	(void)tc_hmac_final(prng->key, sizeof(prng->key), &prng->h);
+	/* configure the new prng key into the prng's instance of hmac */
+	(void)tc_hmac_set_key(&prng->h, prng->key, sizeof(prng->key));
+
+	/* use the new key to compute a new state variable v */
+	(void)tc_hmac_init(&prng->h);
+	(void)tc_hmac_update(&prng->h, prng->v, sizeof(prng->v));
+	(void)tc_hmac_final(prng->v, sizeof(prng->v), &prng->h);
+}
+
+int tc_hmac_prng_init(TCHmacPrng_t prng,
+		      const uint8_t *personalization,
+		      unsigned int plen)
+{
+
+	/* input sanity check: */
+	if (prng == (TCHmacPrng_t) 0 ||
+	    personalization == (uint8_t *) 0 ||
+	    plen > MAX_PLEN) {
+		return TC_CRYPTO_FAIL;
+	}
+
+	/* put the generator into a known state: */
+	_set(prng->key, 0x00, sizeof(prng->key));
+	_set(prng->v, 0x01, sizeof(prng->v));
+	tc_hmac_set_key(&prng->h, prng->key, sizeof(prng->key));
+	/* update assumes SOME key has been configured into HMAC */
+
+	update(prng, personalization, plen);
+
+	/* force a reseed before allowing tc_hmac_prng_generate to succeed: */
+	prng->countdown = 0;
+
+	return TC_CRYPTO_SUCCESS;
+}
+
+int tc_hmac_prng_reseed(TCHmacPrng_t prng,
+			const uint8_t *seed,
+			unsigned int seedlen,
+			const uint8_t *additional_input,
+			unsigned int additionallen)
+{
+
+	/* input sanity check: */
+	if (prng == (TCHmacPrng_t) 0 ||
+	    seed == (const uint8_t *) 0 ||
+	    seedlen < MIN_SLEN ||
+	    seedlen > MAX_SLEN) {
+		return TC_CRYPTO_FAIL;
+	}
+
+	if (additional_input != (const uint8_t *) 0) {
+		/*
+		 * Abort if additional_input is provided but has inappropriate
+		 * length
+		 */
+		if (additionallen == 0 ||
+		    additionallen > MAX_ALEN) {
+			return TC_CRYPTO_FAIL;
+		} else {
+		/* call update for the seed and additional_input */
+		update(prng, seed, seedlen);
+		update(prng, additional_input, additionallen);
+		}
+	} else {
+		/* call update only for the seed */
+		update(prng, seed, seedlen);
+	}
+
+	/* ... and enable hmac_prng_generate */
+	prng->countdown = MAX_GENS;
+
+	return TC_CRYPTO_SUCCESS;
+}
+
+int tc_hmac_prng_generate(uint8_t *out, unsigned int outlen, TCHmacPrng_t prng)
+{
+	unsigned int bufferlen;
+
+	/* input sanity check: */
+	if (out == (uint8_t *) 0 ||
+	    prng == (TCHmacPrng_t) 0 ||
+	    outlen == 0 ||
+	    outlen > MAX_OUT) {
+		return TC_CRYPTO_FAIL;
+	} else if (prng->countdown == 0) {
+		return TC_HMAC_PRNG_RESEED_REQ;
+	}
+
+	prng->countdown--;
+
+	while (outlen != 0) {
+		/* operate HMAC in OFB mode to create "random" outputs */
+		(void)tc_hmac_init(&prng->h);
+		(void)tc_hmac_update(&prng->h, prng->v, sizeof(prng->v));
+		(void)tc_hmac_final(prng->v, sizeof(prng->v), &prng->h);
+
+		bufferlen = (TC_SHA256_DIGEST_SIZE > outlen) ?
+			outlen : TC_SHA256_DIGEST_SIZE;
+		(void)_copy(out, bufferlen, prng->v, bufferlen);
+
+		out += bufferlen;
+		outlen = (outlen > TC_SHA256_DIGEST_SIZE) ?
+			(outlen - TC_SHA256_DIGEST_SIZE) : 0;
+	}
+
+	/* block future PRNG compromises from revealing past state */
+	update(prng, prng->v, TC_SHA256_DIGEST_SIZE);
+
+	return TC_CRYPTO_SUCCESS;
+}