release/src/router/openvpn/crypto.h

   1 /*
   2  *  OpenVPN -- An application to securely tunnel IP networks
   3  *             over a single TCP/UDP port, with support for SSL/TLS-based
   4  *             session authentication and key exchange,
   5  *             packet encryption, packet authentication, and
   6  *             packet compression.
   7  *
   8  *  Copyright (C) 2002-2009 OpenVPN Technologies, Inc. <sales@openvpn.net>
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License version 2
  12  *  as published by the Free Software Foundation.
  13  *
  14  *  This program is distributed in the hope that it will be useful,
  15  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  *  GNU General Public License for more details.
  18  *
  19  *  You should have received a copy of the GNU General Public License
  20  *  along with this program (see the file COPYING included with this
  21  *  distribution); if not, write to the Free Software Foundation, Inc.,
  22  *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23  */
  24
  25 #ifndef CRYPTO_H
  26 #define CRYPTO_H
  27 #ifdef USE_CRYPTO
  28
  29 #define ALLOW_NON_CBC_CIPHERS
  30
  31 /*
  32  * Does our OpenSSL library support crypto hardware acceleration?
  33  */
  34 #if defined(HAVE_OPENSSL_ENGINE_H) && defined(HAVE_ENGINE_LOAD_BUILTIN_ENGINES) && defined(HAVE_ENGINE_REGISTER_ALL_COMPLETE) && defined(HAVE_ENGINE_CLEANUP)
  35 #define CRYPTO_ENGINE 1
  36 #else
  37 #define CRYPTO_ENGINE 0
  38 #endif
  39
  40 #include <openssl/objects.h>
  41 #include <openssl/rand.h>
  42 #include <openssl/evp.h>
  43 #include <openssl/hmac.h>
  44 #include <openssl/des.h>
  45 #include <openssl/md5.h>
  46 #if NTLM
  47 #include <openssl/md4.h>
  48 #endif
  49 #include <openssl/sha.h>
  50 #include <openssl/err.h>
  51
  52 #if CRYPTO_ENGINE
  53 #include <openssl/engine.h>
  54 #endif
  55
  56 #if SSLEAY_VERSION_NUMBER >= 0x00907000L
  57 #include <openssl/des_old.h>
  58 #endif
  59
  60 #include "basic.h"
  61 #include "buffer.h"
  62 #include "packet_id.h"
  63 #include "mtu.h"
  64
  65 /*
  66  * Workarounds for incompatibilites between OpenSSL libraries.
  67  * Right now we accept OpenSSL libraries from 0.9.5 to 0.9.7.
  68  */
  69
  70 #if SSLEAY_VERSION_NUMBER < 0x00907000L
  71
  72 /* Workaround: EVP_CIPHER_mode is defined wrong in OpenSSL 0.9.6 but is fixed in 0.9.7 */
  73 #undef EVP_CIPHER_mode
  74 #define EVP_CIPHER_mode(e)                (((e)->flags) & EVP_CIPH_MODE)
  75
  76 #define DES_cblock                        des_cblock
  77 #define DES_is_weak_key                   des_is_weak_key
  78 #define DES_check_key_parity              des_check_key_parity
  79 #define DES_set_odd_parity                des_set_odd_parity
  80
  81 #define HMAC_CTX_init(ctx)                CLEAR (*ctx)
  82 #define HMAC_Init_ex(ctx,sec,len,md,impl) HMAC_Init(ctx, sec, len, md)
  83 #define HMAC_CTX_cleanup(ctx)             HMAC_cleanup(ctx)
  84 #define EVP_MD_CTX_cleanup(md)            CLEAR (*md)
  85
  86 #define INFO_CALLBACK_SSL_CONST
  87
  88 #endif
  89
  90 #ifndef INFO_CALLBACK_SSL_CONST
  91 #define INFO_CALLBACK_SSL_CONST const
  92 #endif
  93
  94 #if SSLEAY_VERSION_NUMBER < 0x00906000
  95
  96 #undef EVP_CIPHER_mode
  97 #define EVP_CIPHER_mode(x) 1
  98 #define EVP_CIPHER_CTX_mode(x) 1
  99 #define EVP_CIPHER_flags(x) 0
 100
 101 #define EVP_CIPH_CBC_MODE 1
 102 #define EVP_CIPH_CFB_MODE 0
 103 #define EVP_CIPH_OFB_MODE 0
 104 #define EVP_CIPH_VARIABLE_LENGTH 0
 105
 106 #define OPENSSL_malloc(x) malloc(x)
 107 #define OPENSSL_free(x) free(x)
 108
 109 static inline int
 110 EVP_CipherInit_ov (EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, uint8_t *key, uint8_t *iv, int enc)
 111 {
 112   EVP_CipherInit (ctx, type, key, iv, enc);
 113   return 1;
 114 }
 115
 116 static inline int
 117 EVP_CipherUpdate_ov (EVP_CIPHER_CTX *ctx, uint8_t *out, int *outl, uint8_t *in, int inl)
 118 {
 119   EVP_CipherUpdate (ctx, out, outl, in, inl);
 120   return 1;
 121 }
 122
 123 static inline bool
 124 cipher_ok (const char* name)
 125 {
 126   const int i = strlen (name) - 4;
 127   if (i >= 0)
 128     return !strcmp (name + i, "-CBC");
 129   else
 130     return false;
 131 }
 132
 133 #else
 134
 135 static inline int
 136 EVP_CipherInit_ov (EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, uint8_t *key, uint8_t *iv, int enc)
 137 {
 138   return EVP_CipherInit (ctx, type, key, iv, enc);
 139 }
 140
 141 static inline int
 142 EVP_CipherUpdate_ov (EVP_CIPHER_CTX *ctx, uint8_t *out, int *outl, uint8_t *in, int inl)
 143 {
 144   return EVP_CipherUpdate (ctx, out, outl, in, inl);
 145 }
 146
 147 static inline bool
 148 cipher_ok (const char* name)
 149 {
 150   return true;
 151 }
 152
 153 #endif
 154
 155 #if SSLEAY_VERSION_NUMBER < 0x0090581f
 156 #undef DES_check_key_parity
 157 #define DES_check_key_parity(x) 1
 158 #endif
 159
 160 #ifndef EVP_CIPHER_name
 161 #define EVP_CIPHER_name(e)              OBJ_nid2sn(EVP_CIPHER_nid(e))
 162 #endif
 163
 164 #ifndef EVP_MD_name
 165 #define EVP_MD_name(e)                  OBJ_nid2sn(EVP_MD_type(e))
 166 #endif
 167
 168 /*
 169  * Max size in bytes of any cipher key that might conceivably be used.
 170  *
 171  * This value is checked at compile time in crypto.c to make sure
 172  * it is always at least EVP_MAX_KEY_LENGTH.
 173  *
 174  * We define our own value, since this parameter
 175  * is used to control the size of static key files.
 176  * If the OpenSSL library increases EVP_MAX_KEY_LENGTH,
 177  * we don't want our key files to be suddenly rendered
 178  * unusable.
 179  */
 180 #define MAX_CIPHER_KEY_LENGTH 64
 181
 182 /*
 183  * Max size in bytes of any HMAC key that might conceivably be used.
 184  *
 185  * This value is checked at compile time in crypto.c to make sure
 186  * it is always at least EVP_MAX_MD_SIZE.  We define our own value
 187  * for the same reason as above.
 188  */
 189 #define MAX_HMAC_KEY_LENGTH 64
 190
 191 /*
 192  * Defines a key type and key length for both cipher and HMAC.
 193  */
 194 struct key_type
 195 {
 196   uint8_t cipher_length;
 197   uint8_t hmac_length;
 198   const EVP_CIPHER *cipher;
 199   const EVP_MD *digest;
 200 };
 201
 202 /*
 203  * A random key.
 204  */
 205 struct key
 206 {
 207   uint8_t cipher[MAX_CIPHER_KEY_LENGTH];
 208   uint8_t hmac[MAX_HMAC_KEY_LENGTH];
 209 };
 210
 211 #define KEY_DIRECTION_BIDIRECTIONAL 0 /* same keys for both directions */
 212 #define KEY_DIRECTION_NORMAL        1 /* encrypt with keys[0], decrypt with keys[1] */
 213 #define KEY_DIRECTION_INVERSE       2 /* encrypt with keys[1], decrypt with keys[0] */
 214
 215 /*
 216  * Dual random keys (for encrypt/decrypt)
 217  */
 218 struct key2
 219 {
 220   int n;
 221   struct key keys[2];
 222 };
 223
 224 /*
 225  * Used for controlling bidirectional keys
 226  * vs. a separate key for each direction.
 227  */
 228 struct key_direction_state
 229 {
 230   int out_key;
 231   int in_key;
 232   int need_keys;
 233 };
 234
 235 /*
 236  * A key context for cipher and/or HMAC.
 237  */
 238 struct key_ctx
 239 {
 240   EVP_CIPHER_CTX *cipher;
 241   HMAC_CTX *hmac;
 242 };
 243
 244 /*
 245  * Cipher/HMAC key context for both sending and receiving
 246  * directions.
 247  */
 248 struct key_ctx_bi
 249 {
 250   struct key_ctx encrypt;
 251   struct key_ctx decrypt;
 252 };
 253
 254 /*
 255  * Options for encrypt/decrypt.
 256  */
 257 struct crypto_options
 258 {
 259   struct key_ctx_bi *key_ctx_bi;
 260   struct packet_id *packet_id;
 261   struct packet_id_persist *pid_persist;
 262
 263 # define CO_PACKET_ID_LONG_FORM  (1<<0)
 264 # define CO_USE_IV               (1<<1)
 265 # define CO_IGNORE_PACKET_ID     (1<<2)
 266 # define CO_MUTE_REPLAY_WARNINGS (1<<3)
 267   unsigned int flags;
 268 };
 269
 270 void init_key_type (struct key_type *kt, const char *ciphername,
 271                     bool ciphername_defined, const char *authname,
 272                     bool authname_defined, int keysize,
 273                     bool cfb_ofb_allowed, bool warn);
 274
 275 #define RKF_MUST_SUCCEED (1<<0)
 276 #define RKF_INLINE       (1<<1)
 277 void read_key_file (struct key2 *key2, const char *file, const unsigned int flags);
 278
 279 int write_key_file (const int nkeys, const char *filename);
 280
 281 int read_passphrase_hash (const char *passphrase_file,
 282                           const EVP_MD *digest,
 283                           uint8_t *output,
 284                           int len);
 285
 286 void generate_key_random (struct key *key, const struct key_type *kt);
 287
 288 void check_replay_iv_consistency(const struct key_type *kt, bool packet_id, bool use_iv);
 289
 290 bool check_key (struct key *key, const struct key_type *kt);
 291
 292 void fixup_key (struct key *key, const struct key_type *kt);
 293
 294 bool write_key (const struct key *key, const struct key_type *kt,
 295                 struct buffer *buf);
 296
 297 int read_key (struct key *key, const struct key_type *kt, struct buffer *buf);
 298
 299 bool cfb_ofb_mode (const struct key_type* kt);
 300
 301 const char *kt_cipher_name (const struct key_type *kt);
 302 const char *kt_digest_name (const struct key_type *kt);
 303 int kt_key_size (const struct key_type *kt);
 304
 305 /* enc parameter in init_key_ctx */
 306 #define DO_ENCRYPT 1
 307 #define DO_DECRYPT 0
 308
 309 void init_key_ctx (struct key_ctx *ctx, struct key *key,
 310                    const struct key_type *kt, int enc,
 311                    const char *prefix);
 312
 313 void free_key_ctx (struct key_ctx *ctx);
 314 void free_key_ctx_bi (struct key_ctx_bi *ctx);
 315
 316 void openvpn_encrypt (struct buffer *buf, struct buffer work,
 317                       const struct crypto_options *opt,
 318                       const struct frame* frame);
 319
 320 bool openvpn_decrypt (struct buffer *buf, struct buffer work,
 321                       const struct crypto_options *opt,
 322                       const struct frame* frame);
 323
 324
 325 void crypto_adjust_frame_parameters(struct frame *frame,
 326                                     const struct key_type* kt,
 327                                     bool cipher_defined,
 328                                     bool use_iv,
 329                                     bool packet_id,
 330                                     bool packet_id_long_form);
 331
 332 #define NONCE_SECRET_LEN_MIN 16
 333 #define NONCE_SECRET_LEN_MAX 64
 334 void prng_init (const char *md_name, const int nonce_secret_len_parm);
 335 void prng_bytes (uint8_t *output, int len);
 336 void prng_uninit ();
 337
 338 void test_crypto (const struct crypto_options *co, struct frame* f);
 339
 340 const char *md5sum(uint8_t *buf, int len, int n_print_chars, struct gc_arena *gc);
 341
 342 void show_available_ciphers (void);
 343
 344 void show_available_digests (void);
 345
 346 void show_available_engines (void);
 347
 348 void init_crypto_lib_engine (const char *engine_name);
 349
 350 void init_crypto_lib (void);
 351
 352 void uninit_crypto_lib (void);
 353
 354 /* key direction functions */
 355
 356 void key_direction_state_init (struct key_direction_state *kds, int key_direction);
 357
 358 void verify_fix_key2 (struct key2 *key2, const struct key_type *kt, const char *shared_secret_file);
 359
 360 void must_have_n_keys (const char *filename, const char *option, const struct key2 *key2, int n);
 361
 362 int ascii2keydirection (int msglevel, const char *str);
 363
 364 const char *keydirection2ascii (int kd, bool remote);
 365
 366 /* print keys */
 367 void key2_print (const struct key2* k,
 368                  const struct key_type *kt,
 369                  const char* prefix0,
 370                  const char* prefix1);
 371
 372 /* memory debugging */
 373 void openssl_dmalloc_init (void);
 374
 375 #ifdef USE_SSL
 376
 377 #define GHK_INLINE  (1<<0)
 378 void get_tls_handshake_key (const struct key_type *key_type,
 379                             struct key_ctx_bi *ctx,
 380                             const char *passphrase_file,
 381                             const int key_direction,
 382                             const unsigned int flags);
 383
 384 #else
 385
 386 void init_ssl_lib (void);
 387 void free_ssl_lib (void);
 388
 389 #endif /* USE_SSL */
 390
 391 /*
 392  * Inline functions
 393  */
 394
 395 static inline bool
 396 key_ctx_bi_defined(const struct key_ctx_bi* key)
 397 {
 398   return key->encrypt.cipher || key->encrypt.hmac || key->decrypt.cipher || key->decrypt.hmac;
 399 }
 400
 401 /*
 402  * md5 functions
 403  */
 404
 405 struct md5_state {
 406   MD5_CTX ctx;
 407 };
 408
 409 struct md5_digest {
 410   uint8_t digest [MD5_DIGEST_LENGTH];
 411 };
 412
 413 void md5_state_init (struct md5_state *s);
 414 void md5_state_update (struct md5_state *s, void *data, size_t len);
 415 void md5_state_final (struct md5_state *s, struct md5_digest *out);
 416 void md5_digest_clear (struct md5_digest *digest);
 417 bool md5_digest_defined (const struct md5_digest *digest);
 418 bool md5_digest_equal (const struct md5_digest *d1, const struct md5_digest *d2);
 419
 420 #endif /* USE_CRYPTO */
 421 #endif /* CRYPTO_H */