/[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 677 by n-ki, Mon Apr 26 13:48:39 2004 UTC revision 977 by astrand, Mon Aug 8 19:15:57 2005 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 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;
# 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     * I believe this is based on SSLv3 with the following differences:
65     *  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   * General purpose 48-byte transformation, using two 32-byte salts (generally,   * 48-byte transformation used to generate master secret (6.1) and key material (6.2.2).
  * a client and server salt) and a global salt value used for padding.  
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 438  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? */          out_uint16_le(s, 0xca01);       /* colour depth? */
459          out_uint16_le(s, 1);          out_uint16_le(s, 1);
# Line 812  sec_process_mcs_data(STREAM s) Line 818  sec_process_mcs_data(STREAM s)
818    
819  /* Receive secure transport packet */  /* Receive secure transport packet */
820  STREAM  STREAM
821  sec_recv(void)  sec_recv(uint8 * rdpver)
822  {  {
823          uint32 sec_flags;          uint32 sec_flags;
824          uint16 channel;          uint16 channel;
825          STREAM s;          STREAM s;
826    
827          while ((s = mcs_recv(&channel)) != NULL)          while ((s = mcs_recv(&channel, rdpver)) != NULL)
828          {          {
829                    if (rdpver != NULL)
830                    {
831                            if (*rdpver != 3)
832                            {
833                                    if (*rdpver & 0x80)
834                                    {
835                                            in_uint8s(s, 8);        /* signature */
836                                            sec_decrypt(s->p, s->end - s->p);
837                                    }
838                                    return s;
839                            }
840                    }
841                  if (g_encryption || !g_licence_issued)                  if (g_encryption || !g_licence_issued)
842                  {                  {
843                          in_uint32_le(s, sec_flags);                          in_uint32_le(s, sec_flags);
# Line 835  sec_recv(void) Line 853  sec_recv(void)
853                                  licence_process(s);                                  licence_process(s);
854                                  continue;                                  continue;
855                          }                          }
856    
857                            if (sec_flags & 0x0400) /* SEC_REDIRECT_ENCRYPT */
858                            {
859                                    uint8 swapbyte;
860    
861                                    in_uint8s(s, 8);        /* signature */
862                                    sec_decrypt(s->p, s->end - s->p);
863    
864                                    /* Check for a redirect packet, starts with 00 04 */
865                                    if (s->p[0] == 0 && s->p[1] == 4)
866                                    {
867                                            /* for some reason the PDU and the length seem to be swapped.
868                                               This isn't good, but we're going to do a byte for byte
869                                               swap.  So the first foure value appear as: 00 04 XX YY,
870                                               where XX YY is the little endian length. We're going to
871                                               use 04 00 as the PDU type, so after our swap this will look
872                                               like: XX YY 04 00 */
873                                            swapbyte = s->p[0];
874                                            s->p[0] = s->p[2];
875                                            s->p[2] = swapbyte;
876    
877                                            swapbyte = s->p[1];
878                                            s->p[1] = s->p[3];
879                                            s->p[3] = swapbyte;
880    
881                                            swapbyte = s->p[2];
882                                            s->p[2] = s->p[3];
883                                            s->p[3] = swapbyte;
884                                    }
885    #ifdef WITH_DEBUG
886                                    /* warning!  this debug statement will show passwords in the clear! */
887                                    hexdump(s->p, s->end - s->p);
888    #endif
889                            }
890    
891                  }                  }
892    
893                  if (channel != MCS_GLOBAL_CHANNEL)                  if (channel != MCS_GLOBAL_CHANNEL)
894                  {                  {
895                          channel_process(s, channel);                          channel_process(s, channel);
896                          continue;                          *rdpver = 0xff;
897                            return s;
898                  }                  }
899    
900                  return s;                  return s;
# Line 870  sec_connect(char *server, char *username Line 924  sec_connect(char *server, char *username
924          return True;          return True;
925  }  }
926    
927    /* Establish a secure connection */
928    BOOL
929    sec_reconnect(char *server)
930    {
931            struct stream mcs_data;
932    
933            /* We exchange some RDP data during the MCS-Connect */
934            mcs_data.size = 512;
935            mcs_data.p = mcs_data.data = (uint8 *) xmalloc(mcs_data.size);
936            sec_out_mcs_data(&mcs_data);
937    
938            if (!mcs_reconnect(server, &mcs_data))
939                    return False;
940    
941            /*      sec_process_mcs_data(&mcs_data); */
942            if (g_encryption)
943                    sec_establish_key();
944            xfree(mcs_data.data);
945            return True;
946    }
947    
948  /* Disconnect a connection */  /* Disconnect a connection */
949  void  void
950  sec_disconnect(void)  sec_disconnect(void)
951  {  {
952          mcs_disconnect();          mcs_disconnect();
953  }  }
954    
955    /* reset the state of the sec layer */
956    void
957    sec_reset_state(void)
958    {
959            g_server_rdp_version = 0;
960            sec_encrypt_use_count = 0;
961            sec_decrypt_use_count = 0;
962            mcs_reset_state();
963    }
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