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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Copyright (c) 2016, Intel Corporation4 * Authors: Salvatore Benedetto <salvatore.benedetto@intel.com>5 */6#include <linux/kernel.h>7#include <linux/export.h>8#include <linux/err.h>9#include <linux/string.h>10#include <crypto/ecdh.h>11#include <crypto/kpp.h>12 13#define ECDH_KPP_SECRET_MIN_SIZE (sizeof(struct kpp_secret) + sizeof(short))14 15static inline u8 *ecdh_pack_data(void *dst, const void *src, size_t sz)16{17 memcpy(dst, src, sz);18 return dst + sz;19}20 21static inline const u8 *ecdh_unpack_data(void *dst, const void *src, size_t sz)22{23 memcpy(dst, src, sz);24 return src + sz;25}26 27unsigned int crypto_ecdh_key_len(const struct ecdh *params)28{29 return ECDH_KPP_SECRET_MIN_SIZE + params->key_size;30}31EXPORT_SYMBOL_GPL(crypto_ecdh_key_len);32 33int crypto_ecdh_encode_key(char *buf, unsigned int len,34 const struct ecdh *params)35{36 u8 *ptr = buf;37 struct kpp_secret secret = {38 .type = CRYPTO_KPP_SECRET_TYPE_ECDH,39 .len = len40 };41 42 if (unlikely(!buf))43 return -EINVAL;44 45 if (len != crypto_ecdh_key_len(params))46 return -EINVAL;47 48 ptr = ecdh_pack_data(ptr, &secret, sizeof(secret));49 ptr = ecdh_pack_data(ptr, ¶ms->key_size, sizeof(params->key_size));50 ecdh_pack_data(ptr, params->key, params->key_size);51 52 return 0;53}54EXPORT_SYMBOL_GPL(crypto_ecdh_encode_key);55 56int crypto_ecdh_decode_key(const char *buf, unsigned int len,57 struct ecdh *params)58{59 const u8 *ptr = buf;60 struct kpp_secret secret;61 62 if (unlikely(!buf || len < ECDH_KPP_SECRET_MIN_SIZE))63 return -EINVAL;64 65 ptr = ecdh_unpack_data(&secret, ptr, sizeof(secret));66 if (secret.type != CRYPTO_KPP_SECRET_TYPE_ECDH)67 return -EINVAL;68 69 if (unlikely(len < secret.len))70 return -EINVAL;71 72 ptr = ecdh_unpack_data(¶ms->key_size, ptr, sizeof(params->key_size));73 if (secret.len != crypto_ecdh_key_len(params))74 return -EINVAL;75 76 /* Don't allocate memory. Set pointer to data77 * within the given buffer78 */79 params->key = (void *)ptr;80 81 return 0;82}83EXPORT_SYMBOL_GPL(crypto_ecdh_decode_key);84