/[rdesktop]/sourceforge.net/trunk/rdesktop/secure.c
This is repository of my old source code which isn't updated any more. Go to git.rot13.org for current projects!
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Diff of /sourceforge.net/trunk/rdesktop/secure.c

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revision 638 by astrand, Wed Mar 17 14:11:08 2004 UTC revision 1199 by astrand, Mon Mar 27 08:17:34 2006 UTC
# Line 1  Line 1 
1  /* -*- c-basic-offset: 8 -*-  /* -*- c-basic-offset: 8 -*-
2     rdesktop: A Remote Desktop Protocol client.     rdesktop: A Remote Desktop Protocol client.
3     Protocol services - RDP encryption and licensing     Protocol services - RDP encryption and licensing
4     Copyright (C) Matthew Chapman 1999-2002     Copyright (C) Matthew Chapman 1999-2005
5    
6     This program is free software; you can redistribute it and/or modify     This program is free software; you can redistribute it and/or modify
7     it under the terms of the GNU General Public License as published by     it under the terms of the GNU General Public License as published by
# Line 20  Line 20 
20    
21  #include "rdesktop.h"  #include "rdesktop.h"
22    
 #ifdef WITH_OPENSSL  
23  #include <openssl/rc4.h>  #include <openssl/rc4.h>
24  #include <openssl/md5.h>  #include <openssl/md5.h>
25  #include <openssl/sha.h>  #include <openssl/sha.h>
26  #include <openssl/bn.h>  #include <openssl/bn.h>
27  #include <openssl/x509v3.h>  #include <openssl/x509v3.h>
 #else  
 #include "crypto/rc4.h"  
 #include "crypto/md5.h"  
 #include "crypto/sha.h"  
 #include "crypto/bn.h"  
 #endif  
28    
29  extern char hostname[16];  extern char g_hostname[16];
30  extern int g_width;  extern int g_width;
31  extern int g_height;  extern int g_height;
32  extern int keylayout;  extern unsigned int g_keylayout;
33    extern int g_keyboard_type;
34    extern int g_keyboard_subtype;
35    extern int g_keyboard_functionkeys;
36  extern BOOL g_encryption;  extern BOOL g_encryption;
37  extern BOOL g_licence_issued;  extern BOOL g_licence_issued;
38  extern BOOL g_use_rdp5;  extern BOOL g_use_rdp5;
39  extern BOOL g_console_session;  extern BOOL g_console_session;
40  extern int g_server_bpp;  extern int g_server_depth;
41  extern uint16 mcs_userid;  extern uint16 mcs_userid;
42  extern VCHANNEL g_channels[];  extern VCHANNEL g_channels[];
43  extern unsigned int g_num_channels;  extern unsigned int g_num_channels;
# Line 60  static uint8 sec_crypted_random[SEC_MODU Line 56  static uint8 sec_crypted_random[SEC_MODU
56    
57  uint16 g_server_rdp_version = 0;  uint16 g_server_rdp_version = 0;
58    
59    /* These values must be available to reset state - Session Directory */
60    static int sec_encrypt_use_count = 0;
61    static int sec_decrypt_use_count = 0;
62    
63  /*  /*
64   * General purpose 48-byte transformation, using two 32-byte salts (generally,   * I believe this is based on SSLv3 with the following differences:
65   * a client and server salt) and a global salt value used for padding.   *  MAC algorithm (5.2.3.1) uses only 32-bit length in place of seq_num/type/length fields
66     *  MAC algorithm uses SHA1 and MD5 for the two hash functions instead of one or other
67     *  key_block algorithm (6.2.2) uses 'X', 'YY', 'ZZZ' instead of 'A', 'BB', 'CCC'
68     *  key_block partitioning is different (16 bytes each: MAC secret, decrypt key, encrypt key)
69     *  encryption/decryption keys updated every 4096 packets
70     * See http://wp.netscape.com/eng/ssl3/draft302.txt
71     */
72    
73    /*
74     * 48-byte transformation used to generate master secret (6.1) and key material (6.2.2).
75   * Both SHA1 and MD5 algorithms are used.   * Both SHA1 and MD5 algorithms are used.
76   */   */
77  void  void
# Line 93  sec_hash_48(uint8 * out, uint8 * in, uin Line 102  sec_hash_48(uint8 * out, uint8 * in, uin
102  }  }
103    
104  /*  /*
105   * Weaker 16-byte transformation, also using two 32-byte salts, but   * 16-byte transformation used to generate export keys (6.2.2).
  * only using a single round of MD5.  
106   */   */
107  void  void
108  sec_hash_16(uint8 * out, uint8 * in, uint8 * salt1, uint8 * salt2)  sec_hash_16(uint8 * out, uint8 * in, uint8 * salt1, uint8 * salt2)
# Line 117  sec_make_40bit(uint8 * key) Line 125  sec_make_40bit(uint8 * key)
125          key[2] = 0x9e;          key[2] = 0x9e;
126  }  }
127    
128  /* Generate a session key and RC4 keys, given client and server randoms */  /* Generate encryption keys given client and server randoms */
129  static void  static void
130  sec_generate_keys(uint8 * client_key, uint8 * server_key, int rc4_key_size)  sec_generate_keys(uint8 * client_random, uint8 * server_random, int rc4_key_size)
131  {  {
132          uint8 session_key[48];          uint8 pre_master_secret[48];
133          uint8 temp_hash[48];          uint8 master_secret[48];
134          uint8 input[48];          uint8 key_block[48];
135    
136          /* Construct input data to hash */          /* Construct pre-master secret */
137          memcpy(input, client_key, 24);          memcpy(pre_master_secret, client_random, 24);
138          memcpy(input + 24, server_key, 24);          memcpy(pre_master_secret + 24, server_random, 24);
139    
140          /* Generate session key - two rounds of sec_hash_48 */          /* Generate master secret and then key material */
141          sec_hash_48(temp_hash, input, client_key, server_key, 65);          sec_hash_48(master_secret, pre_master_secret, client_random, server_random, 'A');
142          sec_hash_48(session_key, temp_hash, client_key, server_key, 88);          sec_hash_48(key_block, master_secret, client_random, server_random, 'X');
143    
144          /* Store first 16 bytes of session key, for generating signatures */          /* First 16 bytes of key material is MAC secret */
145          memcpy(sec_sign_key, session_key, 16);          memcpy(sec_sign_key, key_block, 16);
146    
147          /* Generate RC4 keys */          /* Generate export keys from next two blocks of 16 bytes */
148          sec_hash_16(sec_decrypt_key, &session_key[16], client_key, server_key);          sec_hash_16(sec_decrypt_key, &key_block[16], client_random, server_random);
149          sec_hash_16(sec_encrypt_key, &session_key[32], client_key, server_key);          sec_hash_16(sec_encrypt_key, &key_block[32], client_random, server_random);
150    
151          if (rc4_key_size == 1)          if (rc4_key_size == 1)
152          {          {
# Line 187  buf_out_uint32(uint8 * buffer, uint32 va Line 195  buf_out_uint32(uint8 * buffer, uint32 va
195          buffer[3] = (value >> 24) & 0xff;          buffer[3] = (value >> 24) & 0xff;
196  }  }
197    
198  /* Generate a signature hash, using a combination of SHA1 and MD5 */  /* Generate a MAC hash (5.2.3.1), using a combination of SHA1 and MD5 */
199  void  void
200  sec_sign(uint8 * signature, int siglen, uint8 * session_key, int keylen, uint8 * data, int datalen)  sec_sign(uint8 * signature, int siglen, uint8 * session_key, int keylen, uint8 * data, int datalen)
201  {  {
# Line 215  sec_sign(uint8 * signature, int siglen, Line 223  sec_sign(uint8 * signature, int siglen,
223          memcpy(signature, md5sig, siglen);          memcpy(signature, md5sig, siglen);
224  }  }
225    
226  /* Update an encryption key - similar to the signing process */  /* Update an encryption key */
227  static void  static void
228  sec_update(uint8 * key, uint8 * update_key)  sec_update(uint8 * key, uint8 * update_key)
229  {  {
# Line 247  sec_update(uint8 * key, uint8 * update_k Line 255  sec_update(uint8 * key, uint8 * update_k
255  static void  static void
256  sec_encrypt(uint8 * data, int length)  sec_encrypt(uint8 * data, int length)
257  {  {
258          static int use_count;          if (sec_encrypt_use_count == 4096)
   
         if (use_count == 4096)  
259          {          {
260                  sec_update(sec_encrypt_key, sec_encrypt_update_key);                  sec_update(sec_encrypt_key, sec_encrypt_update_key);
261                  RC4_set_key(&rc4_encrypt_key, rc4_key_len, sec_encrypt_key);                  RC4_set_key(&rc4_encrypt_key, rc4_key_len, sec_encrypt_key);
262                  use_count = 0;                  sec_encrypt_use_count = 0;
263          }          }
264    
265          RC4(&rc4_encrypt_key, length, data, data);          RC4(&rc4_encrypt_key, length, data, data);
266          use_count++;          sec_encrypt_use_count++;
267  }  }
268    
269  /* Decrypt data using RC4 */  /* Decrypt data using RC4 */
270  void  void
271  sec_decrypt(uint8 * data, int length)  sec_decrypt(uint8 * data, int length)
272  {  {
273          static int use_count;          if (sec_decrypt_use_count == 4096)
   
         if (use_count == 4096)  
274          {          {
275                  sec_update(sec_decrypt_key, sec_decrypt_update_key);                  sec_update(sec_decrypt_key, sec_decrypt_update_key);
276                  RC4_set_key(&rc4_decrypt_key, rc4_key_len, sec_decrypt_key);                  RC4_set_key(&rc4_decrypt_key, rc4_key_len, sec_decrypt_key);
277                  use_count = 0;                  sec_decrypt_use_count = 0;
278          }          }
279    
280          RC4(&rc4_decrypt_key, length, data, data);          RC4(&rc4_decrypt_key, length, data, data);
281          use_count++;          sec_decrypt_use_count++;
282  }  }
283    
284  static void  static void
# Line 402  sec_establish_key(void) Line 406  sec_establish_key(void)
406  static void  static void
407  sec_out_mcs_data(STREAM s)  sec_out_mcs_data(STREAM s)
408  {  {
409          int hostlen = 2 * strlen(hostname);          int hostlen = 2 * strlen(g_hostname);
410          int length = 158 + 76 + 12 + 4;          int length = 158 + 76 + 12 + 4;
411          unsigned int i;          unsigned int i;
412    
# Line 412  sec_out_mcs_data(STREAM s) Line 416  sec_out_mcs_data(STREAM s)
416          if (hostlen > 30)          if (hostlen > 30)
417                  hostlen = 30;                  hostlen = 30;
418    
419          out_uint16_be(s, 5);    /* unknown */          /* Generic Conference Control (T.124) ConferenceCreateRequest */
420            out_uint16_be(s, 5);
421          out_uint16_be(s, 0x14);          out_uint16_be(s, 0x14);
422          out_uint8(s, 0x7c);          out_uint8(s, 0x7c);
423          out_uint16_be(s, 1);          out_uint16_be(s, 1);
# Line 425  sec_out_mcs_data(STREAM s) Line 430  sec_out_mcs_data(STREAM s)
430          out_uint16_le(s, 0xc001);          out_uint16_le(s, 0xc001);
431          out_uint8(s, 0);          out_uint8(s, 0);
432    
433          out_uint32_le(s, 0x61637544);   /* "Duca", as in Ducati. */          out_uint32_le(s, 0x61637544);   /* OEM ID: "Duca", as in Ducati. */
434          out_uint16_be(s, ((length - 14) | 0x8000));     /* remaining length */          out_uint16_be(s, ((length - 14) | 0x8000));     /* remaining length */
435    
436          /* Client information */          /* Client information */
# Line 437  sec_out_mcs_data(STREAM s) Line 442  sec_out_mcs_data(STREAM s)
442          out_uint16_le(s, g_height);          out_uint16_le(s, g_height);
443          out_uint16_le(s, 0xca01);          out_uint16_le(s, 0xca01);
444          out_uint16_le(s, 0xaa03);          out_uint16_le(s, 0xaa03);
445          out_uint32_le(s, keylayout);          out_uint32_le(s, g_keylayout);
446          out_uint32_le(s, 2600); /* Client build. We are now 2600 compatible :-) */          out_uint32_le(s, 2600); /* Client build. We are now 2600 compatible :-) */
447    
448          /* Unicode name of client, padded to 32 bytes */          /* Unicode name of client, padded to 32 bytes */
449          rdp_out_unistr(s, hostname, hostlen);          rdp_out_unistr(s, g_hostname, hostlen);
450          out_uint8s(s, 30 - hostlen);          out_uint8s(s, 30 - hostlen);
451    
452          out_uint32_le(s, 4);          /* See
453          out_uint32(s, 0);             http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wceddk40/html/cxtsksupportingremotedesktopprotocol.asp */
454          out_uint32_le(s, 12);          out_uint32_le(s, g_keyboard_type);
455            out_uint32_le(s, g_keyboard_subtype);
456            out_uint32_le(s, g_keyboard_functionkeys);
457          out_uint8s(s, 64);      /* reserved? 4 + 12 doublewords */          out_uint8s(s, 64);      /* reserved? 4 + 12 doublewords */
458            out_uint16_le(s, 0xca01);       /* colour depth? */
         switch (g_server_bpp)  
         {  
                 case 8:  
                         out_uint16_le(s, 0xca01);  
                         break;  
                 case 15:  
                         out_uint16_le(s, 0xca02);  
                         break;  
                 case 16:  
                         out_uint16_le(s, 0xca03);  
                         break;  
                 case 24:  
                         out_uint16_le(s, 0xca04);  
                         break;  
         }  
459          out_uint16_le(s, 1);          out_uint16_le(s, 1);
460    
461          out_uint32(s, 0);          out_uint32(s, 0);
462          out_uint8(s, g_server_bpp);          out_uint8(s, g_server_depth);
463          out_uint16_le(s, 0x0700);          out_uint16_le(s, 0x0700);
464          out_uint8(s, 0);          out_uint8(s, 0);
465          out_uint32_le(s, 1);          out_uint32_le(s, 1);
# Line 541  sec_parse_x509_key(X509 * cert) Line 533  sec_parse_x509_key(X509 * cert)
533          if (OBJ_obj2nid(cert->cert_info->key->algor->algorithm) == NID_md5WithRSAEncryption)          if (OBJ_obj2nid(cert->cert_info->key->algor->algorithm) == NID_md5WithRSAEncryption)
534          {          {
535                  DEBUG_RDP5(("Re-setting algorithm type to RSA in server certificate\n"));                  DEBUG_RDP5(("Re-setting algorithm type to RSA in server certificate\n"));
536                    ASN1_OBJECT_free(cert->cert_info->key->algor->algorithm);
537                  cert->cert_info->key->algor->algorithm = OBJ_nid2obj(NID_rsaEncryption);                  cert->cert_info->key->algor->algorithm = OBJ_nid2obj(NID_rsaEncryption);
538          }          }
539          epk = X509_get_pubkey(cert);          epk = X509_get_pubkey(cert);
# Line 550  sec_parse_x509_key(X509 * cert) Line 543  sec_parse_x509_key(X509 * cert)
543                  return False;                  return False;
544          }          }
545    
546          server_public_key = (RSA *) epk->pkey.ptr;          server_public_key = RSAPublicKey_dup((RSA *) epk->pkey.ptr);
547    
548            EVP_PKEY_free(epk);
549    
550          return True;          return True;
551  }  }
# Line 688  sec_parse_crypt_info(STREAM s, uint32 * Line 683  sec_parse_crypt_info(STREAM s, uint32 *
683                     MITM-attacks.                     MITM-attacks.
684                   */                   */
685    
686                    X509_free(cacert);
687    
688                  in_uint32_le(s, cert_len);                  in_uint32_le(s, cert_len);
689                  DEBUG_RDP5(("Certificate length is %d\n", cert_len));                  DEBUG_RDP5(("Certificate length is %d\n", cert_len));
690                  server_cert = d2i_X509(NULL, &(s->p), cert_len);                  server_cert = d2i_X509(NULL, &(s->p), cert_len);
# Line 706  sec_parse_crypt_info(STREAM s, uint32 * Line 703  sec_parse_crypt_info(STREAM s, uint32 *
703                  if (!sec_parse_x509_key(server_cert))                  if (!sec_parse_x509_key(server_cert))
704                  {                  {
705                          DEBUG_RDP5(("Didn't parse X509 correctly\n"));                          DEBUG_RDP5(("Didn't parse X509 correctly\n"));
706                            X509_free(server_cert);
707                          return False;                          return False;
708                  }                  }
709                    X509_free(server_cert);
710                  return True;    /* There's some garbage here we don't care about */                  return True;    /* There's some garbage here we don't care about */
711          }          }
712          return s_check_end(s);          return s_check_end(s);
# Line 753  sec_process_crypt_info(STREAM s) Line 752  sec_process_crypt_info(STREAM s)
752    
753                  reverse(sec_crypted_random, SEC_MODULUS_SIZE);                  reverse(sec_crypted_random, SEC_MODULUS_SIZE);
754    
755                    RSA_free(server_public_key);
756                    server_public_key = NULL;
757          }          }
758          else          else
759          {                       /* RDP4-style encryption */          {                       /* RDP4-style encryption */
# Line 770  sec_process_srv_info(STREAM s) Line 771  sec_process_srv_info(STREAM s)
771          in_uint16_le(s, g_server_rdp_version);          in_uint16_le(s, g_server_rdp_version);
772          DEBUG_RDP5(("Server RDP version is %d\n", g_server_rdp_version));          DEBUG_RDP5(("Server RDP version is %d\n", g_server_rdp_version));
773          if (1 == g_server_rdp_version)          if (1 == g_server_rdp_version)
774            {
775                  g_use_rdp5 = 0;                  g_use_rdp5 = 0;
776                    g_server_depth = 8;
777            }
778  }  }
779    
780    
# Line 782  sec_process_mcs_data(STREAM s) Line 786  sec_process_mcs_data(STREAM s)
786          uint8 *next_tag;          uint8 *next_tag;
787          uint8 len;          uint8 len;
788    
789          in_uint8s(s, 21);       /* header (T.124 stuff, probably) */          in_uint8s(s, 21);       /* header (T.124 ConferenceCreateResponse) */
790          in_uint8(s, len);          in_uint8(s, len);
791          if (len & 0x80)          if (len & 0x80)
792                  in_uint8(s, len);                  in_uint8(s, len);
# Line 823  sec_process_mcs_data(STREAM s) Line 827  sec_process_mcs_data(STREAM s)
827    
828  /* Receive secure transport packet */  /* Receive secure transport packet */
829  STREAM  STREAM
830  sec_recv(void)  sec_recv(uint8 * rdpver)
831  {  {
832          uint32 sec_flags;          uint32 sec_flags;
833          uint16 channel;          uint16 channel;
834          STREAM s;          STREAM s;
835    
836          while ((s = mcs_recv(&channel)) != NULL)          while ((s = mcs_recv(&channel, rdpver)) != NULL)
837          {          {
838                    if (rdpver != NULL)
839                    {
840                            if (*rdpver != 3)
841                            {
842                                    if (*rdpver & 0x80)
843                                    {
844                                            in_uint8s(s, 8);        /* signature */
845                                            sec_decrypt(s->p, s->end - s->p);
846                                    }
847                                    return s;
848                            }
849                    }
850                  if (g_encryption || !g_licence_issued)                  if (g_encryption || !g_licence_issued)
851                  {                  {
852                          in_uint32_le(s, sec_flags);                          in_uint32_le(s, sec_flags);
# Line 846  sec_recv(void) Line 862  sec_recv(void)
862                                  licence_process(s);                                  licence_process(s);
863                                  continue;                                  continue;
864                          }                          }
865    
866                            if (sec_flags & 0x0400) /* SEC_REDIRECT_ENCRYPT */
867                            {
868                                    uint8 swapbyte;
869    
870                                    in_uint8s(s, 8);        /* signature */
871                                    sec_decrypt(s->p, s->end - s->p);
872    
873                                    /* Check for a redirect packet, starts with 00 04 */
874                                    if (s->p[0] == 0 && s->p[1] == 4)
875                                    {
876                                            /* for some reason the PDU and the length seem to be swapped.
877                                               This isn't good, but we're going to do a byte for byte
878                                               swap.  So the first foure value appear as: 00 04 XX YY,
879                                               where XX YY is the little endian length. We're going to
880                                               use 04 00 as the PDU type, so after our swap this will look
881                                               like: XX YY 04 00 */
882                                            swapbyte = s->p[0];
883                                            s->p[0] = s->p[2];
884                                            s->p[2] = swapbyte;
885    
886                                            swapbyte = s->p[1];
887                                            s->p[1] = s->p[3];
888                                            s->p[3] = swapbyte;
889    
890                                            swapbyte = s->p[2];
891                                            s->p[2] = s->p[3];
892                                            s->p[3] = swapbyte;
893                                    }
894    #ifdef WITH_DEBUG
895                                    /* warning!  this debug statement will show passwords in the clear! */
896                                    hexdump(s->p, s->end - s->p);
897    #endif
898                            }
899    
900                  }                  }
901    
902                  if (channel != MCS_GLOBAL_CHANNEL)                  if (channel != MCS_GLOBAL_CHANNEL)
903                  {                  {
904                          channel_process(s, channel);                          channel_process(s, channel);
905                          continue;                          *rdpver = 0xff;
906                            return s;
907                  }                  }
908    
909                  return s;                  return s;
# Line 881  sec_connect(char *server, char *username Line 933  sec_connect(char *server, char *username
933          return True;          return True;
934  }  }
935    
936    /* Establish a secure connection */
937    BOOL
938    sec_reconnect(char *server)
939    {
940            struct stream mcs_data;
941    
942            /* We exchange some RDP data during the MCS-Connect */
943            mcs_data.size = 512;
944            mcs_data.p = mcs_data.data = (uint8 *) xmalloc(mcs_data.size);
945            sec_out_mcs_data(&mcs_data);
946    
947            if (!mcs_reconnect(server, &mcs_data))
948                    return False;
949    
950            /*      sec_process_mcs_data(&mcs_data); */
951            if (g_encryption)
952                    sec_establish_key();
953            xfree(mcs_data.data);
954            return True;
955    }
956    
957  /* Disconnect a connection */  /* Disconnect a connection */
958  void  void
959  sec_disconnect(void)  sec_disconnect(void)
960  {  {
961          mcs_disconnect();          mcs_disconnect();
962  }  }
963    
964    /* reset the state of the sec layer */
965    void
966    sec_reset_state(void)
967    {
968            g_server_rdp_version = 0;
969            sec_encrypt_use_count = 0;
970            sec_decrypt_use_count = 0;
971            mcs_reset_state();
972    }
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