crypto: ecdh - Add ECDH software support

* Implement ECDH under kpp API
 * Provide ECC software support for curve P-192 and
   P-256.
 * Add kpp test for ECDH with data generated by OpenSSL
Signed-off-by: Salvatore Benedetto <salvatore.benedetto@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/Kconfig

@@ -118,6 +118,11 @@ config CRYPTO_DH
 	help
 	  Generic implementation of the Diffie-Hellman algorithm.
 
+config CRYPTO_ECDH
+	tristate "ECDH algorithm"
+	select CRYTPO_KPP
+	help
+	  Generic implementation of the ECDH algorithm
 
 config CRYPTO_MANAGER
 	tristate "Cryptographic algorithm manager"

crypto/Makefile

@@ -35,6 +35,10 @@ obj-$(CONFIG_CRYPTO_KPP2) += kpp.o
 dh_generic-y := dh.o
 dh_generic-y += dh_helper.o
 obj-$(CONFIG_CRYPTO_DH) += dh_generic.o
+ecdh_generic-y := ecc.o
+ecdh_generic-y += ecdh.o
+ecdh_generic-y += ecdh_helper.o
+obj-$(CONFIG_CRYPTO_ECDH) += ecdh_generic.o
 
 $(obj)/rsapubkey-asn1.o: $(obj)/rsapubkey-asn1.c $(obj)/rsapubkey-asn1.h
 $(obj)/rsaprivkey-asn1.o: $(obj)/rsaprivkey-asn1.c $(obj)/rsaprivkey-asn1.h

crypto/ecc.h

+/*
+ * Copyright (c) 2013, Kenneth MacKay
+ * 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.
+ *
+ * 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
+ * HOLDER 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.
+ */
+#ifndef _CRYPTO_ECC_H
+#define _CRYPTO_ECC_H
+
+#define ECC_MAX_DIGITS	4 /* 256 */
+
+#define ECC_DIGITS_TO_BYTES_SHIFT 3
+
+/**
+ * ecc_is_key_valid() - Validate a given ECDH private key
+ *
+ * @curve_id:		id representing the curve to use
+ * @ndigits:		curve number of digits
+ * @private_key:	private key to be used for the given curve
+ * @private_key_len:	private key len
+ *
+ * Returns 0 if the key is acceptable, a negative value otherwise
+ */
+int ecc_is_key_valid(unsigned int curve_id, unsigned int ndigits,
+		     const u8 *private_key, unsigned int private_key_len);
+
+/**
+ * ecdh_make_pub_key() - Compute an ECC public key
+ *
+ * @curve_id:		id representing the curve to use
+ * @private_key:	pregenerated private key for the given curve
+ * @private_key_len:	length of private_key
+ * @public_key:		buffer for storing the public key generated
+ * @public_key_len:	length of the public_key buffer
+ *
+ * Returns 0 if the public key was generated successfully, a negative value
+ * if an error occurred.
+ */
+int ecdh_make_pub_key(const unsigned int curve_id, unsigned int ndigits,
+		      const u8 *private_key, unsigned int private_key_len,
+		      u8 *public_key, unsigned int public_key_len);
+
+/**
+ * ecdh_shared_secret() - Compute a shared secret
+ *
+ * @curve_id:		id representing the curve to use
+ * @private_key:	private key of part A
+ * @private_key_len:	length of private_key
+ * @public_key:		public key of counterpart B
+ * @public_key_len:	length of public_key
+ * @secret:		buffer for storing the calculated shared secret
+ * @secret_len:		length of the secret buffer
+ *
+ * Note: It is recommended that you hash the result of ecdh_shared_secret
+ * before using it for symmetric encryption or HMAC.
+ *
+ * Returns 0 if the shared secret was generated successfully, a negative value
+ * if an error occurred.
+ */
+int ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
+		       const u8 *private_key, unsigned int private_key_len,
+		       const u8 *public_key, unsigned int public_key_len,
+		       u8 *secret, unsigned int secret_len);
+#endif

crypto/ecc_curve_defs.h

+#ifndef _CRYTO_ECC_CURVE_DEFS_H
+#define _CRYTO_ECC_CURVE_DEFS_H
+
+struct ecc_point {
+	u64 *x;
+	u64 *y;
+	u8 ndigits;
+};
+
+struct ecc_curve {
+	char *name;
+	struct ecc_point g;
+	u64 *p;
+	u64 *n;
+};
+
+/* NIST P-192 */
+static u64 nist_p192_g_x[] = { 0xF4FF0AFD82FF1012ull, 0x7CBF20EB43A18800ull,
+				0x188DA80EB03090F6ull };
+static u64 nist_p192_g_y[] = { 0x73F977A11E794811ull, 0x631011ED6B24CDD5ull,
+				0x07192B95FFC8DA78ull };
+static u64 nist_p192_p[] = { 0xFFFFFFFFFFFFFFFFull, 0xFFFFFFFFFFFFFFFEull,
+				0xFFFFFFFFFFFFFFFFull };
+static u64 nist_p192_n[] = { 0x146BC9B1B4D22831ull, 0xFFFFFFFF99DEF836ull,
+				0xFFFFFFFFFFFFFFFFull };
+static struct ecc_curve nist_p192 = {
+	.name = "nist_192",
+	.g = {
+		.x = nist_p192_g_x,
+		.y = nist_p192_g_y,
+		.ndigits = 3,
+	},
+	.p = nist_p192_p,
+	.n = nist_p192_n
+};
+
+/* NIST P-256 */
+static u64 nist_p256_g_x[] = { 0xF4A13945D898C296ull, 0x77037D812DEB33A0ull,
+				0xF8BCE6E563A440F2ull, 0x6B17D1F2E12C4247ull };
+static u64 nist_p256_g_y[] = { 0xCBB6406837BF51F5ull, 0x2BCE33576B315ECEull,
+				0x8EE7EB4A7C0F9E16ull, 0x4FE342E2FE1A7F9Bull };
+static u64 nist_p256_p[] = { 0xFFFFFFFFFFFFFFFFull, 0x00000000FFFFFFFFull,
+				0x0000000000000000ull, 0xFFFFFFFF00000001ull };
+static u64 nist_p256_n[] = { 0xF3B9CAC2FC632551ull, 0xBCE6FAADA7179E84ull,
+				0xFFFFFFFFFFFFFFFFull, 0xFFFFFFFF00000000ull };
+static struct ecc_curve nist_p256 = {
+	.name = "nist_256",
+	.g = {
+		.x = nist_p256_g_x,
+		.y = nist_p256_g_y,
+		.ndigits = 4,
+	},
+	.p = nist_p256_p,
+	.n = nist_p256_n
+};
+
+#endif

crypto/ecdh.c

+/* ECDH key-agreement protocol
+ *
+ * Copyright (c) 2016, Intel Corporation
+ * Authors: Salvator Benedetto <salvatore.benedetto@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <crypto/internal/kpp.h>
+#include <crypto/kpp.h>
+#include <crypto/ecdh.h>
+#include <linux/scatterlist.h>
+#include "ecc.h"
+
+struct ecdh_ctx {
+	unsigned int curve_id;
+	unsigned int ndigits;
+	u64 private_key[ECC_MAX_DIGITS];
+	u64 public_key[2 * ECC_MAX_DIGITS];
+	u64 shared_secret[ECC_MAX_DIGITS];
+};
+
+static inline struct ecdh_ctx *ecdh_get_ctx(struct crypto_kpp *tfm)
+{
+	return kpp_tfm_ctx(tfm);
+}
+
+static unsigned int ecdh_supported_curve(unsigned int curve_id)
+{
+	switch (curve_id) {
+	case ECC_CURVE_NIST_P192: return 3;
+	case ECC_CURVE_NIST_P256: return 4;
+	default: return 0;
+	}
+}
+
+static int ecdh_set_secret(struct crypto_kpp *tfm, void *buf, unsigned int len)
+{
+	struct ecdh_ctx *ctx = ecdh_get_ctx(tfm);
+	struct ecdh params;
+	unsigned int ndigits;
+
+	if (crypto_ecdh_decode_key(buf, len, &params) < 0)
+		return -EINVAL;
+
+	ndigits = ecdh_supported_curve(params.curve_id);
+	if (!ndigits)
+		return -EINVAL;
+
+	ctx->curve_id = params.curve_id;
+	ctx->ndigits = ndigits;
+
+	if (ecc_is_key_valid(ctx->curve_id, ctx->ndigits,
+			     (const u8 *)params.key, params.key_size) < 0)
+		return -EINVAL;
+
+	memcpy(ctx->private_key, params.key, params.key_size);
+
+	return 0;
+}
+
+static int ecdh_compute_value(struct kpp_request *req)
+{
+	int ret = 0;
+	struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
+	struct ecdh_ctx *ctx = ecdh_get_ctx(tfm);
+	size_t copied, nbytes;
+	void *buf;
+
+	nbytes = ctx->ndigits << ECC_DIGITS_TO_BYTES_SHIFT;
+
+	if (req->src) {
+		copied = sg_copy_to_buffer(req->src, 1, ctx->public_key,
+					   2 * nbytes);
+		if (copied != 2 * nbytes)
+			return -EINVAL;
+
+		ret = ecdh_shared_secret(ctx->curve_id, ctx->ndigits,
+					 (const u8 *)ctx->private_key, nbytes,
+					 (const u8 *)ctx->public_key, 2 * nbytes,
+					 (u8 *)ctx->shared_secret, nbytes);
+
+		buf = ctx->shared_secret;
+	} else {
+		ret = ecdh_make_pub_key(ctx->curve_id, ctx->ndigits,
+					(const u8 *)ctx->private_key, nbytes,
+					(u8 *)ctx->public_key,
+					sizeof(ctx->public_key));
+		buf = ctx->public_key;
+		/* Public part is a point thus it has both coordinates */
+		nbytes *= 2;
+	}
+
+	if (ret < 0)
+		return ret;
+
+	copied = sg_copy_from_buffer(req->dst, 1, buf, nbytes);
+	if (copied != nbytes)
+		return -EINVAL;
+
+	return ret;
+}
+
+static int ecdh_max_size(struct crypto_kpp *tfm)
+{
+	struct ecdh_ctx *ctx = ecdh_get_ctx(tfm);
+	int nbytes = ctx->ndigits << ECC_DIGITS_TO_BYTES_SHIFT;
+
+	/* Public key is made of two coordinates */
+	return 2 * nbytes;
+}
+
+static void no_exit_tfm(struct crypto_kpp *tfm)
+{
+	return;
+}
+
+static struct kpp_alg ecdh = {
+	.set_secret = ecdh_set_secret,
+	.generate_public_key = ecdh_compute_value,
+	.compute_shared_secret = ecdh_compute_value,
+	.max_size = ecdh_max_size,
+	.exit = no_exit_tfm,
+	.base = {
+		.cra_name = "ecdh",
+		.cra_driver_name = "ecdh-generic",
+		.cra_priority = 100,
+		.cra_module = THIS_MODULE,
+		.cra_ctxsize = sizeof(struct ecdh_ctx),
+	},
+};
+
+static int ecdh_init(void)
+{
+	return crypto_register_kpp(&ecdh);
+}
+
+static void ecdh_exit(void)
+{
+	crypto_unregister_kpp(&ecdh);
+}
+
+module_init(ecdh_init);
+module_exit(ecdh_exit);
+MODULE_ALIAS_CRYPTO("ecdh");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("ECDH generic algorithm");

crypto/ecdh_helper.c

+/*
+ * Copyright (c) 2016, Intel Corporation
+ * Authors: Salvatore Benedetto <salvatore.benedetto@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/err.h>
+#include <linux/string.h>
+#include <crypto/ecdh.h>
+#include <crypto/kpp.h>
+
+#define ECDH_KPP_SECRET_MIN_SIZE (sizeof(struct kpp_secret) + 2 * sizeof(short))
+
+static inline u8 *ecdh_pack_data(void *dst, const void *src, size_t sz)
+{
+	memcpy(dst, src, sz);
+	return dst + sz;
+}
+
+static inline const u8 *ecdh_unpack_data(void *dst, const void *src, size_t sz)
+{
+	memcpy(dst, src, sz);
+	return src + sz;
+}
+
+int crypto_ecdh_key_len(const struct ecdh *params)
+{
+	return ECDH_KPP_SECRET_MIN_SIZE + params->key_size;
+}
+EXPORT_SYMBOL_GPL(crypto_ecdh_key_len);
+
+int crypto_ecdh_encode_key(char *buf, unsigned int len,
+			   const struct ecdh *params)
+{
+	u8 *ptr = buf;
+	struct kpp_secret secret = {
+		.type = CRYPTO_KPP_SECRET_TYPE_ECDH,
+		.len = len
+	};
+
+	if (unlikely(!buf))
+		return -EINVAL;
+
+	if (len != crypto_ecdh_key_len(params))
+		return -EINVAL;
+
+	ptr = ecdh_pack_data(ptr, &secret, sizeof(secret));
+	ptr = ecdh_pack_data(ptr, &params->curve_id, sizeof(params->curve_id));
+	ptr = ecdh_pack_data(ptr, &params->key_size, sizeof(params->key_size));
+	ecdh_pack_data(ptr, params->key, params->key_size);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(crypto_ecdh_encode_key);
+
+int crypto_ecdh_decode_key(const char *buf, unsigned int len,
+			   struct ecdh *params)
+{
+	const u8 *ptr = buf;
+	struct kpp_secret secret;
+
+	if (unlikely(!buf || len < ECDH_KPP_SECRET_MIN_SIZE))
+		return -EINVAL;
+
+	ptr = ecdh_unpack_data(&secret, ptr, sizeof(secret));
+	if (secret.type != CRYPTO_KPP_SECRET_TYPE_ECDH)
+		return -EINVAL;
+
+	ptr = ecdh_unpack_data(&params->curve_id, ptr, sizeof(params->curve_id));
+	ptr = ecdh_unpack_data(&params->key_size, ptr, sizeof(params->key_size));
+	if (secret.len != crypto_ecdh_key_len(params))
+		return -EINVAL;
+
+	/* Don't allocate memory. Set pointer to data
+	 * within the given buffer
+	 */
+	params->key = (void *)ptr;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(crypto_ecdh_decode_key);

crypto/testmgr.c

@@ -3300,6 +3300,16 @@ static const struct alg_test_desc alg_test_descs[] = {
 				}
 			}
 		}
+	}, {
+		.alg = "ecdh",
+		.test = alg_test_kpp,
+		.fips_allowed = 1,
+		.suite = {
+			.kpp = {
+				.vecs = ecdh_tv_template,
+				.count = ECDH_TEST_VECTORS
+			}
+		}
 	}, {
 		.alg = "gcm(aes)",
 		.test = alg_test_aead,

crypto/testmgr.h

@@ -560,6 +560,99 @@ struct kpp_testvec dh_tv_template[] = {
 	}
 };
 
+#ifdef CONFIG_CRYPTO_FIPS
+#define ECDH_TEST_VECTORS 1
+#else
+#define ECDH_TEST_VECTORS 2
+#endif
+struct kpp_testvec ecdh_tv_template[] = {
+	{
+#ifndef CONFIG_CRYPTO_FIPS
+	.secret =
+#ifdef __LITTLE_ENDIAN
+	"\x02\x00" /* type */
+	"\x20\x00" /* len */
+	"\x01\x00" /* curve_id */
+	"\x18\x00" /* key_size */
+#else
+	"\x00\x02" /* type */
+	"\x00\x20" /* len */
+	"\x00\x01" /* curve_id */
+	"\x00\x18" /* key_size */
+#endif
+	"\xb5\x05\xb1\x71\x1e\xbf\x8c\xda"
+	"\x4e\x19\x1e\x62\x1f\x23\x23\x31"
+	"\x36\x1e\xd3\x84\x2f\xcc\x21\x72",
+	.b_public =
+	"\xc3\xba\x67\x4b\x71\xec\xd0\x76"
+	"\x7a\x99\x75\x64\x36\x13\x9a\x94"
+	"\x5d\x8b\xdc\x60\x90\x91\xfd\x3f"
+	"\xb0\x1f\x8a\x0a\x68\xc6\x88\x6e"
+	"\x83\x87\xdd\x67\x09\xf8\x8d\x96"
+	"\x07\xd6\xbd\x1c\xe6\x8d\x9d\x67",
+	.expected_a_public =
+	"\x1a\x04\xdb\xa5\xe1\xdd\x4e\x79"
+	"\xa3\xe6\xef\x0e\x5c\x80\x49\x85"
+	"\xfa\x78\xb4\xef\x49\xbd\x4c\x7c"
+	"\x22\x90\x21\x02\xf9\x1b\x81\x5d"
+	"\x0c\x8a\xa8\x98\xd6\x27\x69\x88"
+	"\x5e\xbc\x94\xd8\x15\x9e\x21\xce",
+	.expected_ss =
+	"\xf4\x57\xcc\x4f\x1f\x4e\x31\xcc"
+	"\xe3\x40\x60\xc8\x06\x93\xc6\x2e"
+	"\x99\x80\x81\x28\xaf\xc5\x51\x74",
+	.secret_size = 32,
+	.b_public_size = 48,
+	.expected_a_public_size = 48,
+	.expected_ss_size = 24
+	}, {
+#endif
+	.secret =
+#ifdef __LITTLE_ENDIAN
+	"\x02\x00" /* type */
+	"\x28\x00" /* len */
+	"\x02\x00" /* curve_id */
+	"\x20\x00" /* key_size */
+#else
+	"\x00\x02" /* type */
+	"\x00\x28" /* len */
+	"\x00\x02" /* curve_id */
+	"\x00\x20" /* key_size */
+#endif
+	"\x24\xd1\x21\xeb\xe5\xcf\x2d\x83"
+	"\xf6\x62\x1b\x6e\x43\x84\x3a\xa3"
+	"\x8b\xe0\x86\xc3\x20\x19\xda\x92"
+	"\x50\x53\x03\xe1\xc0\xea\xb8\x82",
+	.expected_a_public =
+	"\x1a\x7f\xeb\x52\x00\xbd\x3c\x31"
+	"\x7d\xb6\x70\xc1\x86\xa6\xc7\xc4"
+	"\x3b\xc5\x5f\x6c\x6f\x58\x3c\xf5"
+	"\xb6\x63\x82\x77\x33\x24\xa1\x5f"
+	"\x6a\xca\x43\x6f\xf7\x7e\xff\x02"
+	"\x37\x08\xcc\x40\x5e\x7a\xfd\x6a"
+	"\x6a\x02\x6e\x41\x87\x68\x38\x77"
+	"\xfa\xa9\x44\x43\x2d\xef\x09\xdf",
+	.expected_ss =
+	"\xea\x17\x6f\x7e\x6e\x57\x26\x38"
+	"\x8b\xfb\x41\xeb\xba\xc8\x6d\xa5"
+	"\xa8\x72\xd1\xff\xc9\x47\x3d\xaa"
+	"\x58\x43\x9f\x34\x0f\x8c\xf3\xc9",
+	.b_public =
+	"\xcc\xb4\xda\x74\xb1\x47\x3f\xea"
+	"\x6c\x70\x9e\x38\x2d\xc7\xaa\xb7"
+	"\x29\xb2\x47\x03\x19\xab\xdd\x34"
+	"\xbd\xa8\x2c\x93\xe1\xa4\x74\xd9"
+	"\x64\x63\xf7\x70\x20\x2f\xa4\xe6"
+	"\x9f\x4a\x38\xcc\xc0\x2c\x49\x2f"
+	"\xb1\x32\xbb\xaf\x22\x61\xda\xcb"
+	"\x6f\xdb\xa9\xaa\xfc\x77\x81\xf3",
+	.secret_size = 40,
+	.b_public_size = 64,
+	.expected_a_public_size = 64,
+	.expected_ss_size = 32
+	}
+};
+
 /*
  * MD4 test vectors from RFC1320
  */

include/crypto/ecdh.h

+/*
+ * ECDH params to be used with kpp API
+ *
+ * Copyright (c) 2016, Intel Corporation
+ * Authors: Salvatore Benedetto <salvatore.benedetto@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ */
+#ifndef _CRYPTO_ECDH_
+#define _CRYPTO_ECDH_
+
+/* Curves IDs */
+#define ECC_CURVE_NIST_P192	0x0001
+#define ECC_CURVE_NIST_P256	0x0002
+
+struct ecdh {
+	unsigned short curve_id;
+	char *key;
+	unsigned short key_size;
+};
+
+int crypto_ecdh_key_len(const struct ecdh *params);
+int crypto_ecdh_encode_key(char *buf, unsigned int len, const struct ecdh *p);
+int crypto_ecdh_decode_key(const char *buf, unsigned int len, struct ecdh *p);
+
+#endif

include/crypto/kpp.h

@@ -243,6 +243,7 @@ static inline void kpp_request_set_output(struct kpp_request *req,
 enum {
 	CRYPTO_KPP_SECRET_TYPE_UNKNOWN,
 	CRYPTO_KPP_SECRET_TYPE_DH,
+	CRYPTO_KPP_SECRET_TYPE_ECDH,
 };
 
 /**