Eric Lee / smarc-fsl-linux-kernel

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crypto/ecdh_helper.c 2.26 KB
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3c4b23901   Salvatore Benedetto   crypto: ecdh - Ad... 
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  /*
   * 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);