[linux.git] / crypto / dh_helper.c

/*
 * Copyright (c) 2016, Intel Corporation
 * Authors: Salvatore Benedetto <[email protected]>
 *
 * 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.
 */
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/err.h>
#include <linux/string.h>
#include <crypto/dh.h>
#include <crypto/kpp.h>

#define DH_KPP_SECRET_MIN_SIZE (sizeof(struct kpp_secret) + 3 * sizeof(int))

static inline u8 *dh_pack_data(void *dst, const void *src, size_t size)
{
	memcpy(dst, src, size);
	return dst + size;
}

static inline const u8 *dh_unpack_data(void *dst, const void *src, size_t size)
{
	memcpy(dst, src, size);
	return src + size;
}

static inline unsigned int dh_data_size(const struct dh *p)
{
	return p->key_size + p->p_size + p->g_size;
}

unsigned int crypto_dh_key_len(const struct dh *p)
{
	return DH_KPP_SECRET_MIN_SIZE + dh_data_size(p);
}
EXPORT_SYMBOL_GPL(crypto_dh_key_len);

int crypto_dh_encode_key(char *buf, unsigned int len, const struct dh *params)
{
	u8 *ptr = buf;
	struct kpp_secret secret = {
		.type = CRYPTO_KPP_SECRET_TYPE_DH,
		.len = len
	};

	if (unlikely(!buf))
		return -EINVAL;

	if (len != crypto_dh_key_len(params))
		return -EINVAL;

	ptr = dh_pack_data(ptr, &secret, sizeof(secret));
	ptr = dh_pack_data(ptr, &params->key_size, sizeof(params->key_size));
	ptr = dh_pack_data(ptr, &params->p_size, sizeof(params->p_size));
	ptr = dh_pack_data(ptr, &params->g_size, sizeof(params->g_size));
	ptr = dh_pack_data(ptr, params->key, params->key_size);
	ptr = dh_pack_data(ptr, params->p, params->p_size);
	dh_pack_data(ptr, params->g, params->g_size);

	return 0;
}
EXPORT_SYMBOL_GPL(crypto_dh_encode_key);

int crypto_dh_decode_key(const char *buf, unsigned int len, struct dh *params)
{
	const u8 *ptr = buf;
	struct kpp_secret secret;

	if (unlikely(!buf || len < DH_KPP_SECRET_MIN_SIZE))
		return -EINVAL;

	ptr = dh_unpack_data(&secret, ptr, sizeof(secret));
	if (secret.type != CRYPTO_KPP_SECRET_TYPE_DH)
		return -EINVAL;

	ptr = dh_unpack_data(&params->key_size, ptr, sizeof(params->key_size));
	ptr = dh_unpack_data(&params->p_size, ptr, sizeof(params->p_size));
	ptr = dh_unpack_data(&params->g_size, ptr, sizeof(params->g_size));
	if (secret.len != crypto_dh_key_len(params))
		return -EINVAL;

	/*
	 * Don't permit the buffer for 'key' or 'g' to be larger than 'p', since
	 * some drivers assume otherwise.
	 */
	if (params->key_size > params->p_size ||
	    params->g_size > params->p_size)
		return -EINVAL;

	/* Don't allocate memory. Set pointers to data within
	 * the given buffer
	 */
	params->key = (void *)ptr;
	params->p = (void *)(ptr + params->key_size);
	params->g = (void *)(ptr + params->key_size + params->p_size);

	/*
	 * Don't permit 'p' to be 0.  It's not a prime number, and it's subject
	 * to corner cases such as 'mod 0' being undefined or
	 * crypto_kpp_maxsize() returning 0.
	 */
	if (memchr_inv(params->p, 0, params->p_size) == NULL)
		return -EINVAL;

	return 0;
}
EXPORT_SYMBOL_GPL(crypto_dh_decode_key);
Commit	Line	Data
802c7f1c SB	1	/*
	2	* Copyright (c) 2016, Intel Corporation
	3	* Authors: Salvatore Benedetto <[email protected]>
	4	*
	5	* This program is free software; you can redistribute it and/or
c0ca1215	6	* modify it under the terms of the GNU General Public License
802c7f1c	7	* as published by the Free Software Foundation; either version
c0ca1215	8	* 2 of the License, or (at your option) any later version.
802c7f1c SB	9	*/
	10	#include <linux/kernel.h>
	11	#include <linux/export.h>
	12	#include <linux/err.h>
	13	#include <linux/string.h>
	14	#include <crypto/dh.h>
	15	#include <crypto/kpp.h>
	16
	17	#define DH_KPP_SECRET_MIN_SIZE (sizeof(struct kpp_secret) + 3 * sizeof(int))
	18
	19	static inline u8 dh_pack_data(void dst, const void *src, size_t size)
	20	{
	21	memcpy(dst, src, size);
	22	return dst + size;
	23	}
	24
	25	static inline const u8 dh_unpack_data(void dst, const void *src, size_t size)
	26	{
	27	memcpy(dst, src, size);
	28	return src + size;
	29	}
	30
cb195b36	31	static inline unsigned int dh_data_size(const struct dh *p)
802c7f1c SB	32	{
	33	return p->key_size + p->p_size + p->g_size;
	34	}
	35
5b3f3a8b	36	unsigned int crypto_dh_key_len(const struct dh *p)
802c7f1c SB	37	{
	38	return DH_KPP_SECRET_MIN_SIZE + dh_data_size(p);
	39	}
	40	EXPORT_SYMBOL_GPL(crypto_dh_key_len);
	41
	42	int crypto_dh_encode_key(char buf, unsigned int len, const struct dh params)
	43	{
	44	u8 *ptr = buf;
	45	struct kpp_secret secret = {
	46	.type = CRYPTO_KPP_SECRET_TYPE_DH,
	47	.len = len
	48	};
	49
	50	if (unlikely(!buf))
	51	return -EINVAL;
	52
	53	if (len != crypto_dh_key_len(params))
	54	return -EINVAL;
	55
	56	ptr = dh_pack_data(ptr, &secret, sizeof(secret));
	57	ptr = dh_pack_data(ptr, &params->key_size, sizeof(params->key_size));
	58	ptr = dh_pack_data(ptr, &params->p_size, sizeof(params->p_size));
	59	ptr = dh_pack_data(ptr, &params->g_size, sizeof(params->g_size));
	60	ptr = dh_pack_data(ptr, params->key, params->key_size);
	61	ptr = dh_pack_data(ptr, params->p, params->p_size);
	62	dh_pack_data(ptr, params->g, params->g_size);
	63
	64	return 0;
	65	}
	66	EXPORT_SYMBOL_GPL(crypto_dh_encode_key);
	67
	68	int crypto_dh_decode_key(const char buf, unsigned int len, struct dh params)
	69	{
	70	const u8 *ptr = buf;
	71	struct kpp_secret secret;
	72
	73	if (unlikely(!buf \|\| len < DH_KPP_SECRET_MIN_SIZE))
	74	return -EINVAL;
	75
	76	ptr = dh_unpack_data(&secret, ptr, sizeof(secret));
	77	if (secret.type != CRYPTO_KPP_SECRET_TYPE_DH)
	78	return -EINVAL;
	79
	80	ptr = dh_unpack_data(&params->key_size, ptr, sizeof(params->key_size));
	81	ptr = dh_unpack_data(&params->p_size, ptr, sizeof(params->p_size));
	82	ptr = dh_unpack_data(&params->g_size, ptr, sizeof(params->g_size));
	83	if (secret.len != crypto_dh_key_len(params))
	84	return -EINVAL;
	85
ccd9888f EB	86	/*
	87	* Don't permit the buffer for 'key' or 'g' to be larger than 'p', since
	88	* some drivers assume otherwise.
	89	*/
	90	if (params->key_size > params->p_size \|\|
	91	params->g_size > params->p_size)
	92	return -EINVAL;
	93
802c7f1c SB	94	/* Don't allocate memory. Set pointers to data within
	95	* the given buffer
	96	*/
	97	params->key = (void *)ptr;
	98	params->p = (void *)(ptr + params->key_size);
	99	params->g = (void *)(ptr + params->key_size + params->p_size);
	100
199512b1 EB	101	/*
	102	* Don't permit 'p' to be 0. It's not a prime number, and it's subject
	103	* to corner cases such as 'mod 0' being undefined or
	104	* crypto_kpp_maxsize() returning 0.
	105	*/
	106	if (memchr_inv(params->p, 0, params->p_size) == NULL)
	107	return -EINVAL;
	108
802c7f1c SB	109	return 0;
	110	}
	111	EXPORT_SYMBOL_GPL(crypto_dh_decode_key);