ssl/s3_enc.c

   1 /* ssl/s3_enc.c */
   2 /* Copyright (C) 1995-1997 Eric Young (eay@cryptsoft.com)
   3  * All rights reserved.
   4  *
   5  * This package is an SSL implementation written
   6  * by Eric Young (eay@cryptsoft.com).
   7  * The implementation was written so as to conform with Netscapes SSL.
   8  *
   9  * This library is free for commercial and non-commercial use as long as
  10  * the following conditions are aheared to.  The following conditions
  11  * apply to all code found in this distribution, be it the RC4, RSA,
  12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  13  * included with this distribution is covered by the same copyright terms
  14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  15  *
  16  * Copyright remains Eric Young's, and as such any Copyright notices in
  17  * the code are not to be removed.
  18  * If this package is used in a product, Eric Young should be given attribution
  19  * as the author of the parts of the library used.
  20  * This can be in the form of a textual message at program startup or
  21  * in documentation (online or textual) provided with the package.
  22  *
  23  * Redistribution and use in source and binary forms, with or without
  24  * modification, are permitted provided that the following conditions
  25  * are met:
  26  * 1. Redistributions of source code must retain the copyright
  27  *    notice, this list of conditions and the following disclaimer.
  28  * 2. Redistributions in binary form must reproduce the above copyright
  29  *    notice, this list of conditions and the following disclaimer in the
  30  *    documentation and/or other materials provided with the distribution.
  31  * 3. All advertising materials mentioning features or use of this software
  32  *    must display the following acknowledgement:
  33  *    "This product includes cryptographic software written by
  34  *     Eric Young (eay@cryptsoft.com)"
  35  *    The word 'cryptographic' can be left out if the rouines from the library
  36  *    being used are not cryptographic related :-).
  37  * 4. If you include any Windows specific code (or a derivative thereof) from
  38  *    the apps directory (application code) you must include an acknowledgement:
  39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  40  *
  41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  51  * SUCH DAMAGE.
  52  *
  53  * The licence and distribution terms for any publically available version or
  54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  55  * copied and put under another distribution licence
  56  * [including the GNU Public Licence.]
  57  */
  58
  59 #include <stdio.h>
  60 #include "evp.h"
  61 #include "ssl_locl.h"
  62
  63 static unsigned char ssl3_pad_1[48]={
  64         0x36,0x36,0x36,0x36,0x36,0x36,0x36,0x36,
  65         0x36,0x36,0x36,0x36,0x36,0x36,0x36,0x36,
  66         0x36,0x36,0x36,0x36,0x36,0x36,0x36,0x36,
  67         0x36,0x36,0x36,0x36,0x36,0x36,0x36,0x36,
  68         0x36,0x36,0x36,0x36,0x36,0x36,0x36,0x36,
  69         0x36,0x36,0x36,0x36,0x36,0x36,0x36,0x36 };
  70
  71 static unsigned char ssl3_pad_2[48]={
  72         0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,
  73         0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,
  74         0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,
  75         0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,
  76         0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,
  77         0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c,0x5c };
  78
  79 int ssl3_change_cipher_state(s,which)
  80 SSL *s;
  81 int which;
  82         {
  83         unsigned char *p,*key_block,*mac_secret;
  84         unsigned char exp_key[EVP_MAX_KEY_LENGTH];
  85         unsigned char exp_iv[EVP_MAX_KEY_LENGTH];
  86         unsigned char *ms,*key,*iv,*er1,*er2;
  87         EVP_CIPHER_CTX *dd;
  88         EVP_CIPHER *c;
  89         SSL_COMPRESSION *comp;
  90         EVP_MD *m;
  91         MD5_CTX md;
  92         int exp,n,i,j,k;
  93
  94         exp=(s->s3->tmp.new_cipher->algorithms & SSL_EXPORT)?1:0;
  95         c=s->s3->tmp.new_sym_enc;
  96         m=s->s3->tmp.new_hash;
  97         comp=s->s3->tmp.new_compression;
  98         key_block=s->s3->tmp.key_block;
  99
 100         if (which & SSL3_CC_READ)
 101                 {
 102                 if ((s->enc_read_ctx == NULL) &&
 103                         ((s->enc_read_ctx=(EVP_CIPHER_CTX *)
 104                         Malloc(sizeof(EVP_CIPHER_CTX))) == NULL))
 105                         goto err;
 106                 dd= s->enc_read_ctx;
 107                 s->read_hash=m;
 108                 s->read_compression=comp;
 109                 memset(&(s->s3->read_sequence[0]),0,8);
 110                 mac_secret= &(s->s3->read_mac_secret[0]);
 111                 }
 112         else
 113                 {
 114                 if ((s->enc_write_ctx == NULL) &&
 115                         ((s->enc_write_ctx=(EVP_CIPHER_CTX *)
 116                         Malloc(sizeof(EVP_CIPHER_CTX))) == NULL))
 117                         goto err;
 118                 dd= s->enc_write_ctx;
 119                 s->write_hash=m;
 120                 s->write_compression=comp;
 121                 memset(&(s->s3->write_sequence[0]),0,8);
 122                 mac_secret= &(s->s3->write_mac_secret[0]);
 123                 }
 124
 125         p=s->s3->tmp.key_block;
 126         i=EVP_MD_size(m);
 127         j=(exp)?5:EVP_CIPHER_key_length(c);
 128         k=EVP_CIPHER_iv_length(c);
 129         if (    (which == SSL3_CHANGE_CIPHER_CLIENT_WRITE) ||
 130                 (which == SSL3_CHANGE_CIPHER_SERVER_READ))
 131                 {
 132                 ms=  &(p[ 0]); n=i+i;
 133                 key= &(p[ n]); n+=j+j;
 134                 iv=  &(p[ n]); n+=k+k;
 135                 er1= &(s->s3->client_random[0]);
 136                 er2= &(s->s3->server_random[0]);
 137                 }
 138         else
 139                 {
 140                 n=i;
 141                 ms=  &(p[ n]); n+=i+j;
 142                 key= &(p[ n]); n+=j+k;
 143                 iv=  &(p[ n]); n+=k;
 144                 er1= &(s->s3->server_random[0]);
 145                 er2= &(s->s3->client_random[0]);
 146                 }
 147
 148         if (n > s->s3->tmp.key_block_length)
 149                 {
 150                 SSLerr(SSL_F_SSL3_CHANGE_CIPHER_STATE,SSL_R_INTERNAL_ERROR);
 151                 goto err2;
 152                 }
 153
 154         memcpy(mac_secret,ms,i);
 155         if (exp)
 156                 {
 157                 /* In here I set both the read and write key/iv to the
 158                  * same value since only the correct one will be used :-).
 159                  */
 160                 MD5_Init(&md);
 161                 MD5_Update(&md,key,j);
 162                 MD5_Update(&md,er1,SSL3_RANDOM_SIZE);
 163                 MD5_Update(&md,er2,SSL3_RANDOM_SIZE);
 164                 MD5_Final(&(exp_key[0]),&md);
 165                 key= &(exp_key[0]);
 166
 167                 MD5_Init(&md);
 168                 MD5_Update(&md,er1,SSL3_RANDOM_SIZE);
 169                 MD5_Update(&md,er2,SSL3_RANDOM_SIZE);
 170                 MD5_Final(&(exp_iv[0]),&md);
 171                 iv= &(exp_iv[0]);
 172                 }
 173
 174         s->session->key_arg_length=k;
 175         if (k > 0)
 176                 memcpy(&(s->session->key_arg[0]),iv,k);
 177
 178         EVP_CipherInit(dd,c,key,iv,(which & SSL3_CC_WRITE));
 179         memset(&(exp_key[0]),0,sizeof(exp_key));
 180         memset(&(exp_iv[0]),0,sizeof(exp_iv));
 181         return(1);
 182 err:
 183         SSLerr(SSL_F_SSL3_CHANGE_CIPHER_STATE,ERR_R_MALLOC_FAILURE);
 184 err2:
 185         return(0);
 186         }
 187
 188 int ssl3_setup_key_block(s)
 189 SSL *s;
 190         {
 191         unsigned char *p;
 192         EVP_CIPHER *c;
 193         EVP_MD *hash;
 194         int num,exp;
 195
 196         if (s->s3->tmp.key_block_length != 0)
 197                 return(1);
 198
 199         if (!ssl_cipher_get_evp(s->session->cipher,&c,&hash))
 200                 {
 201                 SSLerr(SSL_F_SSL3_SETUP_KEY_BLOCK,SSL_R_CIPHER_OR_HASH_UNAVAILABLE);
 202                 return(0);
 203                 }
 204
 205         s->s3->tmp.new_sym_enc=c;
 206         s->s3->tmp.new_hash=hash;
 207
 208         exp=(s->session->cipher->algorithms & SSL_EXPORT)?1:0;
 209
 210         num=EVP_CIPHER_key_length(c)+EVP_MD_size(hash)+EVP_CIPHER_iv_length(c);
 211         num*=2;
 212
 213         ssl3_cleanup_key_block(s);
 214
 215         if ((p=(unsigned char *)Malloc(num)) == NULL)
 216                 goto err;
 217
 218         s->s3->tmp.key_block_length=num;
 219         s->s3->tmp.key_block=p;
 220
 221         ssl3_generate_key_block(s,p,num);
 222
 223         return(1);
 224 err:
 225         SSLerr(SSL_F_SSL3_SETUP_KEY_BLOCK,ERR_R_MALLOC_FAILURE);
 226         return(0);
 227         }
 228
 229 void ssl3_cleanup_key_block(s)
 230 SSL *s;
 231         {
 232         if (s->s3->tmp.key_block != NULL)
 233                 {
 234                 memset(s->s3->tmp.key_block,0,
 235                         s->s3->tmp.key_block_length);
 236                 Free(s->s3->tmp.key_block);
 237                 s->s3->tmp.key_block=NULL;
 238                 }
 239         s->s3->tmp.key_block_length=0;
 240         }
 241
 242 int ssl3_enc(s,send)
 243 SSL *s;
 244 int send;
 245         {
 246         SSL3_RECORD *rec;
 247         EVP_CIPHER_CTX *ds;
 248         unsigned long l;
 249         int bs,i;
 250         EVP_CIPHER *enc;
 251         SSL_COMPRESSION *comp;
 252
 253         if (send)
 254                 {
 255                 ds=s->enc_write_ctx;
 256                 rec= &(s->s3->wrec);
 257                 if (s->enc_write_ctx == NULL)
 258                         { enc=NULL; comp=NULL; }
 259                 else
 260                         {
 261                         enc=EVP_CIPHER_CTX_cipher(s->enc_write_ctx);
 262                         comp=s->write_compression;
 263                         }
 264                 }
 265         else
 266                 {
 267                 ds=s->enc_read_ctx;
 268                 rec= &(s->s3->rrec);
 269                 if (s->enc_read_ctx == NULL)
 270                         { enc=NULL; comp=NULL; }
 271                 else
 272                         {
 273                         enc=EVP_CIPHER_CTX_cipher(s->enc_read_ctx);
 274                         comp=s->read_compression;
 275                         }
 276                 }
 277
 278         if ((s->session == NULL) || (ds == NULL) ||
 279                 ((enc == NULL) && (comp == NULL)))
 280                 {
 281                 memcpy(rec->data,rec->input,rec->length);
 282                 rec->input=rec->data;
 283                 }
 284         else
 285                 {
 286                 l=rec->length;
 287                 bs=EVP_CIPHER_block_size(ds->cipher);
 288
 289                 /* This should be using (bs-1) and bs instead of 7 and 8 */
 290                 if ((bs != 1) && send)
 291                         {
 292                         i=bs-((int)l%bs);
 293
 294                         /* we need to add 'i-1' padding bytes */
 295                         l+=i;
 296                         rec->length+=i;
 297                         rec->input[l-1]=(i-1);
 298                         }
 299
 300                 EVP_Cipher(ds,rec->data,rec->input,l);
 301
 302                 if ((bs != 1) && !send)
 303                         {
 304                         i=rec->data[l-1]+1;
 305                         if (i > bs)
 306                                 {
 307                                 SSLerr(SSL_F_SSL3_ENC,SSL_R_BLOCK_CIPHER_PAD_IS_WRONG);
 308                                 ssl3_send_alert(s,SSL3_AL_FATAL,SSL3_AD_BAD_RECORD_MAC);
 309                                 return(0);
 310                                 }
 311                         rec->length-=i;
 312                         }
 313                 }
 314         return(1);
 315         }
 316
 317 void ssl3_init_finished_mac(s)
 318 SSL *s;
 319         {
 320         EVP_DigestInit(&(s->s3->finish_dgst1),EVP_md5());
 321         EVP_DigestInit(&(s->s3->finish_dgst2),EVP_sha1());
 322         }
 323
 324 void ssl3_finish_mac(s,buf,len)
 325 SSL *s;
 326 unsigned char *buf;
 327 int len;
 328         {
 329         EVP_DigestUpdate(&(s->s3->finish_dgst1),buf,len);
 330         EVP_DigestUpdate(&(s->s3->finish_dgst2),buf,len);
 331         }
 332
 333 int ssl3_final_finish_mac(s,in_ctx,sender,p)
 334 SSL *s;
 335 EVP_MD_CTX *in_ctx;
 336 unsigned char *sender;
 337 unsigned char *p;
 338         {
 339         unsigned int ret;
 340         int npad,n;
 341         unsigned int i;
 342         unsigned char md_buf[EVP_MAX_MD_SIZE];
 343         EVP_MD_CTX ctx;
 344
 345         memcpy(&ctx,in_ctx,sizeof(EVP_MD_CTX));
 346
 347         n=EVP_MD_CTX_size(&ctx);
 348         npad=(48/n)*n;
 349
 350         if (sender != NULL)
 351                 EVP_DigestUpdate(&ctx,sender,4);
 352         EVP_DigestUpdate(&ctx,s->session->master_key,
 353                 s->session->master_key_length);
 354         EVP_DigestUpdate(&ctx,ssl3_pad_1,npad);
 355         EVP_DigestFinal(&ctx,md_buf,&i);
 356
 357         EVP_DigestInit(&ctx,EVP_MD_CTX_type(&ctx));
 358         EVP_DigestUpdate(&ctx,s->session->master_key,
 359                 s->session->master_key_length);
 360         EVP_DigestUpdate(&ctx,ssl3_pad_2,npad);
 361         EVP_DigestUpdate(&ctx,md_buf,i);
 362         EVP_DigestFinal(&ctx,p,&ret);
 363
 364         memset(&ctx,0,sizeof(EVP_MD_CTX));
 365
 366         return((int)ret);
 367         }
 368
 369 int ssl3_mac(ssl,md,send)
 370 SSL *ssl;
 371 unsigned char *md;
 372 int send;
 373         {
 374         SSL3_RECORD *rec;
 375         unsigned char *mac_sec,*seq;
 376         EVP_MD_CTX md_ctx;
 377         EVP_MD *hash;
 378         unsigned char *p,rec_char;
 379         unsigned int md_size;
 380         int npad,i;
 381
 382         if (send)
 383                 {
 384                 rec= &(ssl->s3->wrec);
 385                 mac_sec= &(ssl->s3->write_mac_secret[0]);
 386                 seq= &(ssl->s3->write_sequence[0]);
 387                 hash=ssl->write_hash;
 388                 }
 389         else
 390                 {
 391                 rec= &(ssl->s3->rrec);
 392                 mac_sec= &(ssl->s3->read_mac_secret[0]);
 393                 seq= &(ssl->s3->read_sequence[0]);
 394                 hash=ssl->read_hash;
 395                 }
 396
 397         md_size=EVP_MD_size(hash);
 398         npad=(48/md_size)*md_size;
 399
 400 #ifdef MAC_DEBUG
 401 printf("npad=%d md_size=%d",npad,md_size);
 402 printf("\nmsec=");
 403 for (i=0; i<md_size; i++) printf("%02X ",mac_sec[i]);
 404 printf("\npad1=");
 405 for (i=0; i<npad; i++) printf("%02X ",ssl3_pad_1[i]);
 406 printf("\nseq =");
 407 for (i=0; i<8; i++) printf("%02X ",seq[i]);
 408 printf("\nreqt=%02X len=%04X\n",rec->type,rec->length);
 409 for (i=0; i<rec->length; i++) printf("%02X",rec->input[i]);
 410 printf("\n");
 411 #endif
 412
 413         /* Chop the digest off the end :-) */
 414
 415         EVP_DigestInit(  &md_ctx,hash);
 416         EVP_DigestUpdate(&md_ctx,mac_sec,md_size);
 417         EVP_DigestUpdate(&md_ctx,ssl3_pad_1,npad);
 418         EVP_DigestUpdate(&md_ctx,seq,8);
 419         rec_char=rec->type;
 420         EVP_DigestUpdate(&md_ctx,&rec_char,1);
 421         p=md;
 422         s2n(rec->length,p);
 423         EVP_DigestUpdate(&md_ctx,md,2);
 424         EVP_DigestUpdate(&md_ctx,rec->input,rec->length);
 425         EVP_DigestFinal( &md_ctx,md,NULL);
 426
 427         EVP_DigestInit(  &md_ctx,hash);
 428         EVP_DigestUpdate(&md_ctx,mac_sec,md_size);
 429         EVP_DigestUpdate(&md_ctx,ssl3_pad_2,npad);
 430         EVP_DigestUpdate(&md_ctx,md,md_size);
 431         EVP_DigestFinal( &md_ctx,md,&md_size);
 432
 433         for (i=7; i>=0; i--)
 434                 if (++seq[i]) break;
 435
 436 #ifdef MAC_DEBUG
 437 printf("md=");
 438 for (i=0; i<md_size; i++) printf("%02X ",md[i]);
 439 printf("\n");
 440 #endif
 441
 442         return(md_size);
 443         }
 444
 445 int ssl3_generate_master_secret(s,out,p,len)
 446 SSL *s;
 447 unsigned char *out;
 448 unsigned char *p;
 449 int len;
 450         {
 451         static unsigned char *salt[3]={
 452                 (unsigned char *)"A",
 453                 (unsigned char *)"BB",
 454                 (unsigned char *)"CCC",
 455                 };
 456         unsigned char buf[EVP_MAX_MD_SIZE];
 457         EVP_MD_CTX ctx;
 458         int i,ret=0;
 459         unsigned int n;
 460
 461         for (i=0; i<3; i++)
 462                 {
 463                 EVP_DigestInit(&ctx,EVP_sha1());
 464                 EVP_DigestUpdate(&ctx,salt[i],strlen((char *)salt[i]));
 465                 EVP_DigestUpdate(&ctx,p,len);
 466                 EVP_DigestUpdate(&ctx,&(s->s3->client_random[0]),
 467                         SSL3_RANDOM_SIZE);
 468                 EVP_DigestUpdate(&ctx,&(s->s3->server_random[0]),
 469                         SSL3_RANDOM_SIZE);
 470                 EVP_DigestFinal(&ctx,buf,&n);
 471
 472                 EVP_DigestInit(&ctx,EVP_md5());
 473                 EVP_DigestUpdate(&ctx,p,len);
 474                 EVP_DigestUpdate(&ctx,buf,n);
 475                 EVP_DigestFinal(&ctx,out,&n);
 476                 out+=n;
 477                 ret+=n;
 478                 }
 479         return(ret);
 480         }
 481