src/libstrongswan/plugins/openssl/openssl_hasher.c

   1 /*
   2  * Copyright (C) 2008 Tobias Brunner
   3  * Hochschule fuer Technik Rapperswil
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the
   7  * Free Software Foundation; either version 2 of the License, or (at your
   8  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  12  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * for more details.
  14  *
  15  * $Id$
  16  */
  17
  18 #include "openssl_hasher.h"
  19
  20 #include <openssl/evp.h>
  21
  22 typedef struct private_openssl_hasher_t private_openssl_hasher_t;
  23
  24 /**
  25  * Private data of openssl_hasher_t
  26  */
  27 struct private_openssl_hasher_t {
  28
  29         /**
  30          * Public part of this class.
  31          */
  32         openssl_hasher_t public;
  33
  34         /**
  35          * data collected to hash
  36          */
  37         chunk_t data;
  38
  39         /*
  40          * the hasher to use
  41          */
  42         const EVP_MD *hasher;
  43 };
  44
  45 /**
  46  * Mapping from the algorithms defined in IKEv2 to
  47  * OpenSSL algorithm names
  48  */
  49 typedef struct {
  50         /**
  51          * Identifier specified in IKEv2
  52          */
  53         int ikev2_id;
  54
  55         /**
  56          * Name of the algorithm, as used in OpenSSL
  57          */
  58         char *name;
  59 } openssl_algorithm_t;
  60
  61 #define END_OF_LIST -1
  62
  63 /**
  64  * Algorithms for integrity
  65  */
  66 static openssl_algorithm_t integrity_algs[] = {
  67         {HASH_MD2,              "md2"},
  68         {HASH_MD5,              "md5"},
  69         {HASH_SHA1,             "sha1"},
  70         {HASH_SHA256,   "sha256"},
  71         {HASH_SHA384,   "sha384"},
  72         {HASH_SHA512,   "sha512"},
  73         {END_OF_LIST,   NULL},
  74 };
  75
  76 /**
  77  * Look up an OpenSSL algorithm name
  78  */
  79 static char* lookup_algorithm(openssl_algorithm_t *openssl_algo,
  80                                            u_int16_t ikev2_algo)
  81 {
  82         while (openssl_algo->ikev2_id != END_OF_LIST)
  83         {
  84                 if (ikev2_algo == openssl_algo->ikev2_id)
  85                 {
  86                         return openssl_algo->name;
  87                 }
  88                 openssl_algo++;
  89         }
  90         return NULL;
  91 }
  92
  93 /**
  94  * append data to the to-be-hashed buffer
  95  */
  96 static void append_data(private_openssl_hasher_t *this, chunk_t data)
  97 {
  98         this->data.ptr = realloc(this->data.ptr, this->data.len + data.len);
  99         memcpy(this->data.ptr + this->data.len, data.ptr, data.len);
 100         this->data.len += data.len;
 101 }
 102
 103 /**
 104  * hash a buffer of data
 105  */
 106 static void hash_data(private_openssl_hasher_t *this, chunk_t data, u_int8_t *digest)
 107 {
 108         EVP_MD_CTX ctx;
 109         EVP_MD_CTX_init(&ctx);
 110         EVP_DigestInit_ex(&ctx, this->hasher, NULL);
 111         EVP_DigestUpdate(&ctx, data.ptr, data.len);
 112         EVP_DigestFinal_ex(&ctx, digest, NULL);
 113         EVP_MD_CTX_cleanup(&ctx);
 114 }
 115
 116 /**
 117  * Implementation of hasher_t.get_hash_size.
 118  */
 119 static size_t get_hash_size(private_openssl_hasher_t *this)
 120 {
 121         return this->hasher->md_size;
 122 }
 123
 124 /**
 125  * Implementation of hasher_t.reset.
 126  */
 127 static void reset(private_openssl_hasher_t *this)
 128 {
 129         chunk_free(&this->data);
 130 }
 131
 132 /**
 133  * Implementation of hasher_t.get_hash.
 134  */
 135 static void get_hash(private_openssl_hasher_t *this, chunk_t chunk,
 136                                          u_int8_t *hash)
 137 {
 138         if (hash)
 139         {
 140                 if (this->data.len)
 141                 {
 142                         append_data(this, chunk);
 143                         hash_data(this, this->data, hash);
 144                 }
 145                 else
 146                 {   /* hash directly if no previous data found */
 147                         hash_data(this, chunk, hash);
 148                 }
 149                 reset(this);
 150         }
 151         else
 152         {
 153                 append_data(this, chunk);
 154         }
 155 }
 156
 157 /**
 158  * Implementation of hasher_t.allocate_hash.
 159  */
 160 static void allocate_hash(private_openssl_hasher_t *this, chunk_t chunk,
 161                                                   chunk_t *hash)
 162 {
 163         if (hash)
 164         {
 165                 *hash = chunk_alloc(get_hash_size(this));
 166                 get_hash(this, chunk, hash->ptr);
 167         }
 168         else
 169         {
 170                 get_hash(this, chunk, NULL);
 171         }
 172 }
 173
 174 /**
 175  * Implementation of hasher_t.destroy.
 176  */
 177 static void destroy (private_openssl_hasher_t *this)
 178 {
 179         free(this->data.ptr);
 180         free(this);
 181 }
 182
 183 /*
 184  * Described in header
 185  */
 186 openssl_hasher_t *openssl_hasher_create(hash_algorithm_t algo)
 187 {
 188         private_openssl_hasher_t *this;
 189
 190         char* name = lookup_algorithm(integrity_algs, algo);
 191         if (!name)
 192         {
 193                 /* algo unavailable */
 194                 return NULL;
 195         }
 196
 197         this = malloc_thing(private_openssl_hasher_t);
 198
 199         this->hasher = EVP_get_digestbyname(name);
 200         if (!this->hasher)
 201         {
 202                 /* OpenSSL does not support the requested algo */
 203                 free(this);
 204                 return NULL;
 205         }
 206
 207         this->public.hasher_interface.get_hash = (void (*) (hasher_t*, chunk_t, u_int8_t*))get_hash;
 208         this->public.hasher_interface.allocate_hash = (void (*) (hasher_t*, chunk_t, chunk_t*))allocate_hash;
 209         this->public.hasher_interface.get_hash_size = (size_t (*) (hasher_t*))get_hash_size;
 210         this->public.hasher_interface.reset = (void (*) (hasher_t*))reset;
 211         this->public.hasher_interface.destroy = (void (*) (hasher_t*))destroy;
 212
 213         this->data = chunk_empty;
 214
 215         return &this->public;
 216 }