CVS: rdesktop licence.c,1.29,1.30 secure.c,1.43,1.44

Update of /cvsroot/rdesktop/rdesktop
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv29067

Modified Files:
	licence.c secure.c 
Log Message:
Document differences between RDP encryption and SSLv3, and bring some
of the terminology in line with the SSLv3 specification.


Index: licence.c
===================================================================
RCS file: /cvsroot/rdesktop/rdesktop/licence.c,v
retrieving revision 1.29
retrieving revision 1.30
diff -C2 -d -r1.29 -r1.30
*** licence.c	28 Jul 2003 21:41:12 -0000	1.29
--- licence.c	16 May 2004 11:18:20 -0000	1.30
***************
*** 37,54 ****
  /* Generate a session key and RC4 keys, given client and server randoms */
  static void
! licence_generate_keys(uint8 * client_key, uint8 * server_key, uint8 * client_rsa)
  {
! 	uint8 session_key[48];
! 	uint8 temp_hash[48];
  
! 	/* Generate session key - two rounds of sec_hash_48 */
! 	sec_hash_48(temp_hash, client_rsa, client_key, server_key, 65);
! 	sec_hash_48(session_key, temp_hash, server_key, client_key, 65);
  
! 	/* Store first 16 bytes of session key, for generating signatures */
! 	memcpy(g_licence_sign_key, session_key, 16);
  
! 	/* Generate RC4 key */
! 	sec_hash_16(g_licence_key, &session_key[16], client_key, server_key);
  }
  
--- 37,54 ----
  /* Generate a session key and RC4 keys, given client and server randoms */
  static void
! licence_generate_keys(uint8 * client_random, uint8 * server_random, uint8 * pre_master_secret)
  {
! 	uint8 master_secret[48];
! 	uint8 key_block[48];
  
! 	/* Generate master secret and then key material */
! 	sec_hash_48(master_secret, pre_master_secret, client_random, server_random, 'A');
! 	sec_hash_48(key_block,     master_secret,     server_random, client_random, 'A');
  
! 	/* Store first 16 bytes of session key as MAC secret */
! 	memcpy(g_licence_sign_key, key_block, 16);
  
! 	/* Generate RC4 key from next 16 bytes */
! 	sec_hash_16(g_licence_key, &key_block[16], client_random, server_random);
  }
  

Index: secure.c
===================================================================
RCS file: /cvsroot/rdesktop/rdesktop/secure.c,v
retrieving revision 1.43
retrieving revision 1.44
diff -C2 -d -r1.43 -r1.44
*** secure.c	26 Apr 2004 13:48:39 -0000	1.43
--- secure.c	16 May 2004 11:18:20 -0000	1.44
***************
*** 62,67 ****
  
  /*
!  * General purpose 48-byte transformation, using two 32-byte salts (generally,
!  * a client and server salt) and a global salt value used for padding.
   * Both SHA1 and MD5 algorithms are used.
   */
--- 62,76 ----
  
  /*
!  * I believe this is based on SSLv3 with the following differences:
!  *  MAC algorithm (5.2.3.1) uses only 32-bit length in place of seq_num/type/length fields
!  *  MAC algorithm uses SHA1 and MD5 for the two hash functions instead of one or other
!  *  key_block algorithm (6.2.2) uses 'X', 'YY', 'ZZZ' instead of 'A', 'BB', 'CCC'
!  *  key_block partitioning is different (16 bytes each: MAC secret, decrypt key, encrypt key)
!  *  encryption/decryption keys updated every 4096 packets
!  * See http://wp.netscape.com/eng/ssl3/draft302.txt
!  */
! 
! /*
!  * 48-byte transformation used to generate master secret (6.1) and key material (6.2.2).
   * Both SHA1 and MD5 algorithms are used.
   */
***************
*** 94,99 ****
  
  /*
!  * Weaker 16-byte transformation, also using two 32-byte salts, but
!  * only using a single round of MD5.
   */
  void
--- 103,107 ----
  
  /*
!  * 16-byte transformation used to generate export keys (6.2.2).
   */
  void
***************
*** 118,143 ****
  }
  
! /* Generate a session key and RC4 keys, given client and server randoms */
  static void
! sec_generate_keys(uint8 * client_key, uint8 * server_key, int rc4_key_size)
  {
! 	uint8 session_key[48];
! 	uint8 temp_hash[48];
! 	uint8 input[48];
  
! 	/* Construct input data to hash */
! 	memcpy(input, client_key, 24);
! 	memcpy(input + 24, server_key, 24);
  
! 	/* Generate session key - two rounds of sec_hash_48 */
! 	sec_hash_48(temp_hash, input, client_key, server_key, 65);
! 	sec_hash_48(session_key, temp_hash, client_key, server_key, 88);
  
! 	/* Store first 16 bytes of session key, for generating signatures */
! 	memcpy(sec_sign_key, session_key, 16);
  
! 	/* Generate RC4 keys */
! 	sec_hash_16(sec_decrypt_key, &session_key[16], client_key, server_key);
! 	sec_hash_16(sec_encrypt_key, &session_key[32], client_key, server_key);
  
  	if (rc4_key_size == 1)
--- 126,151 ----
  }
  
! /* Generate encryption keys given client and server randoms */
  static void
! sec_generate_keys(uint8 * client_random, uint8 * server_random, int rc4_key_size)
  {
! 	uint8 pre_master_secret[48];
! 	uint8 master_secret[48];
! 	uint8 key_block[48];
  
! 	/* Construct pre-master secret */
! 	memcpy(pre_master_secret,      client_random, 24);
! 	memcpy(pre_master_secret + 24, server_random, 24);
  
! 	/* Generate master secret and then key material */
! 	sec_hash_48(master_secret, pre_master_secret, client_random, server_random, 'A');
! 	sec_hash_48(key_block,     master_secret,     client_random, server_random, 'X');
  
! 	/* First 16 bytes of key material is MAC secret */
! 	memcpy(sec_sign_key, key_block, 16);
  
! 	/* Generate export keys from next two blocks of 16 bytes */
! 	sec_hash_16(sec_decrypt_key, &key_block[16], client_random, server_random);
! 	sec_hash_16(sec_encrypt_key, &key_block[32], client_random, server_random);
  
  	if (rc4_key_size == 1)
***************
*** 188,192 ****
  }
  
! /* Generate a signature hash, using a combination of SHA1 and MD5 */
  void
  sec_sign(uint8 * signature, int siglen, uint8 * session_key, int keylen, uint8 * data, int datalen)
--- 196,200 ----
  }
  
! /* Generate a MAC hash (5.2.3.1), using a combination of SHA1 and MD5 */
  void
  sec_sign(uint8 * signature, int siglen, uint8 * session_key, int keylen, uint8 * data, int datalen)
***************
*** 216,220 ****
  }
  
! /* Update an encryption key - similar to the signing process */
  static void
  sec_update(uint8 * key, uint8 * update_key)
--- 224,228 ----
  }
  
! /* Update an encryption key */
  static void
  sec_update(uint8 * key, uint8 * update_key)



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