1: /*
   2: ** crypto.c                                  Crypto extension to pidentd.
   3: **
   4: ** This file is in the public domain. -- Planar 1994.02.21
   5: **
   6: ** Crypto routines.
   7: */
   8: 
   9: #ifdef INCLUDE_CRYPT
  10: 
  11: #ifdef NeXT31
  12: #  include <libc.h>
  13: #endif
  14: 
  15: #include <stdio.h>
  16: 
  17: #include <sys/types.h>
  18: #include <netinet/in.h>
  19: 
  20: #ifndef HPUX7
  21: #  include <arpa/inet.h>
  22: #endif
  23: 
  24: #include <sys/stat.h>
  25: #include <sys/time.h>
  26: 
  27: #include <des.h>
  28: 
  29: typedef unsigned short int_16;
  30: typedef unsigned int   int_32;
  31: 
  32: struct info
  33: {
  34:   int_32 checksum;
  35:   int_16 random;
  36:   int_16 uid;
  37:   int_32 date;
  38:   int_32 ip_local;
  39:   int_32 ip_remote;
  40:   int_16 port_local;
  41:   int_16 port_remote;
  42: };
  43: 
  44: typedef union data
  45: {
  46:   struct info   fields;
  47:   int_32        longs[6];
  48:   unsigned char chars[24];
  49: } data;
  50: 
  51: static char result[33];
  52: des_key_schedule sched;
  53: 
  54: char to_asc[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  55: 
  56: char to_bin[] =
  57: {
  58:     0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
  59:     0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
  60:     0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
  61:     0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
  62:     0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
  63:     0x80, 0x80, 0x80, 0x3e, 0x80, 0x80, 0x80, 0x3f,
  64:     0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b,
  65:     0x3c, 0x3d, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
  66:     0x80, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
  67:     0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e,
  68:     0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16,
  69:     0x17, 0x18, 0x19, 0x80, 0x80, 0x80, 0x80, 0x80,
  70:     0x80, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20,
  71:     0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28,
  72:     0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x30,
  73:     0x31, 0x32, 0x33, 0x80, 0x80, 0x80, 0x80, 0x80,
  74: };
  75: 
  76: 
  77: void init_encryption(key_text)
  78:     char *key_text;
  79: {
  80:     des_cblock key_bin;
  81: 
  82:     des_string_to_key(key_text, &key_bin);
  83:     des_set_key(&key_bin, sched);
  84: }
  85: 
  86: char *make_packet(uid, laddr, lport, faddr, fport)
  87:     int uid;
  88:     struct in_addr *laddr, *faddr;
  89:     int lport, fport;
  90: {
  91:     struct timeval tv;
  92:     union data r;
  93:     int res, i, j;
  94: 
  95:     res = gettimeofday(&tv, NULL);
  96:     srand(tv.tv_usec);
  97: 
  98:     r.fields.random = rand();
  99:     r.fields.uid = htons(uid);
 100:     if (res == 0)
 101:     {
 102:     r.fields.date = htonl(tv.tv_sec);
 103:     }
 104:     else
 105:     {
 106:     r.fields.date = htonl(0);
 107:     }
 108: 
 109:     r.fields.ip_local = laddr->s_addr;
 110:     r.fields.ip_remote = faddr->s_addr;
 111:     r.fields.port_local = htons(lport);
 112:     r.fields.port_remote = htons(fport);
 113: 
 114:     r.fields.checksum = 0;
 115:     for (i = 1; i < 6; i++)
 116:     {
 117:     r.longs[0] ^= r.longs[i];
 118:     }
 119: 
 120:     des_ecb_encrypt((des_cblock *)&(r.longs[0]), (des_cblock *)&(r.longs[0]),
 121:             sched, DES_ENCRYPT);
 122:     r.longs[2] ^= r.longs[0];
 123:     r.longs[3] ^= r.longs[1];
 124: 
 125:     des_ecb_encrypt((des_cblock *)&(r.longs[2]), (des_cblock *)&(r.longs[2]),
 126:             sched, DES_ENCRYPT);
 127:     r.longs[4] ^= r.longs[2];
 128:     r.longs[5] ^= r.longs[3];
 129: 
 130:     des_ecb_encrypt((des_cblock *)&(r.longs[4]), (des_cblock *)&(r.longs[4]),
 131:             sched, DES_ENCRYPT);
 132: 
 133:     for (i = 0, j = 0; i < 24; i+=3, j+=4)
 134:     {
 135:     result[j  ] = to_asc[63 & (r.chars[i  ] >> 2)];
 136:     result[j+1] = to_asc[63 & ((r.chars[i  ] << 4) + (r.chars[i+1] >> 4))];
 137:     result[j+2] = to_asc[63 & ((r.chars[i+1] << 2) + (r.chars[i+2] >> 6))];
 138:     result[j+3] = to_asc[63 & (r.chars[i+2])];
 139:     }
 140:     result[32] = '\0';
 141: 
 142:     return result;
 143: }
 144: 
 145: #define MAX_KEYS 1024
 146: 
 147: static des_cblock keys[MAX_KEYS];
 148: static int num_keys;
 149: 
 150: void init_decryption(key_file)
 151:     FILE *key_file;
 152: {
 153:     char buf[1024];
 154: 
 155:     num_keys = 0;
 156: 
 157:     while (fgets(buf, 1024, key_file) != NULL && num_keys < MAX_KEYS)
 158:     {
 159:     des_string_to_key(buf, &keys[num_keys++]);
 160:     }
 161: 
 162:     des_set_key (&keys [0], sched);
 163: }
 164: 
 165: 
 166: static char readable[75];
 167: 
 168: char *decrypt_packet(packet)
 169:     char *packet;
 170: {
 171:     union data r;
 172:     int i, j, k;
 173:     time_t date_in_sec;
 174:     char *date_in_ascii;
 175: 
 176:     for (k = -1; k < num_keys; k++)
 177:     {
 178:     if (k >= 0)
 179:         des_set_key(&keys [k], sched);
 180: 
 181:     for(i = 0, j = 0; i < 24; i+=3, j+=4)
 182:     {
 183:         r.chars[i  ] = (to_bin[packet[j  ]]<<2)+(to_bin[packet[j+1]]>>4);
 184:         r.chars[i+1] = (to_bin[packet[j+1]]<<4)+(to_bin[packet[j+2]]>>2);
 185:         r.chars[i+2] = (to_bin[packet[j+2]] << 6) + (to_bin[packet[j+3]]);
 186:     }
 187: 
 188:     des_ecb_encrypt((des_cblock *)&(r.longs[4]),
 189:             (des_cblock *)&(r.longs[4]),
 190:             sched, DES_DECRYPT);
 191:     r.longs[4] ^= r.longs[2];
 192:     r.longs[5] ^= r.longs[3];
 193: 
 194:     des_ecb_encrypt((des_cblock *)&(r.longs[2]),
 195:             (des_cblock *)&(r.longs[2]),
 196:             sched, DES_DECRYPT);
 197: 
 198:     r.longs[2] ^= r.longs[0];
 199:     r.longs[3] ^= r.longs[1];
 200:     des_ecb_encrypt((des_cblock *)&(r.longs[0]),
 201:             (des_cblock *)&(r.longs[0]),
 202:             sched, DES_DECRYPT);
 203: 
 204:     for (i = 1; i < 6; i++)
 205:     {
 206:         r.longs[0] ^= r.longs[i];
 207:     }
 208: 
 209:     if (r.fields.checksum == 0)
 210:         goto GoodKey;
 211:     }
 212:     return NULL;
 213: 
 214:   GoodKey:
 215:     date_in_sec = ntohl(r.fields.date);
 216:     date_in_ascii = ctime(&date_in_sec);
 217: 
 218:     sprintf(readable, "%24.24s %u %u.%u.%u.%u %u %u.%u.%u.%u %u",
 219:         date_in_ascii, ntohs(r.fields.uid),
 220:         ((unsigned char *) &r.fields.ip_local)[0],
 221:         ((unsigned char *) &r.fields.ip_local)[1],
 222:         ((unsigned char *) &r.fields.ip_local)[2],
 223:         ((unsigned char *) &r.fields.ip_local)[3],
 224:         (unsigned) ntohs(r.fields.port_local),
 225:         ((unsigned char *) &r.fields.ip_remote)[0],
 226:         ((unsigned char *) &r.fields.ip_remote)[1],
 227:         ((unsigned char *) &r.fields.ip_remote)[2],
 228:         ((unsigned char *) &r.fields.ip_remote)[3],
 229:         (unsigned) ntohs(r.fields.port_remote));
 230: 
 231:     return readable;
 232: }
 233: 
 234: #else
 235: 
 236: #ifndef NeXT31
 237: int dummy = 0;   /* Just here to make some compilers shut up :-) */
 238: #endif
 239: 
 240: #endif

Defined functions

Defined variables

dummy defined in line 237; never used
num_keys defined in line 148; used 4 times
readable defined in line 166; used 2 times
result defined in line 51; used 6 times
to_asc defined in line 54; used 4 times
to_bin defined in line 56; used 6 times

Defined struct's

info defined in line 32; used 2 times
  • in line 46(2)

Defined union's

data defined in line 44; used 4 times

Defined typedef's

data defined in line 49; never used
int_16 defined in line 29; used 4 times
int_32 defined in line 30; used 5 times

Defined macros

MAX_KEYS defined in line 145; used 2 times
Last modified: 1996-11-14
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