/* * 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/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 int dh_data_size(const struct dh *p) { return p->key_size + p->p_size + p->g_size; } 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, ¶ms->key_size, sizeof(params->key_size)); ptr = dh_pack_data(ptr, ¶ms->p_size, sizeof(params->p_size)); ptr = dh_pack_data(ptr, ¶ms->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(¶ms->key_size, ptr, sizeof(params->key_size)); ptr = dh_unpack_data(¶ms->p_size, ptr, sizeof(params->p_size)); ptr = dh_unpack_data(¶ms->g_size, ptr, sizeof(params->g_size)); if (secret.len != crypto_dh_key_len(params)) 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); return 0; } EXPORT_SYMBOL_GPL(crypto_dh_decode_key);