184 lines
3.5 KiB
C
184 lines
3.5 KiB
C
/*
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* keygen.c
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* WEP Key Generators
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*
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* This program generates WEP keys using de facto standard key
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* generators for 40 and 128 bit keys.
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*
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* Link against OpenSSL's libcrypto.a
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*
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* I place this code in the public domain.
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* May 2001, Tim Newsham
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <openssl/md5.h>
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#define WEPKEYSIZE 5
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#define WEPSTRONGKEYSIZE 13
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#define WEPKEYS 4
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#define WEPKEYSTORE (WEPKEYSIZE * WEPKEYS)
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#define WEPSTRONGKEYSTORE (WEPSTRONGKEYSIZE * WEPKEYS)
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/*
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* generate four subkeys from a seed using the defacto standard
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*/
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void
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wep_seedkeygen(int val, u_char *keys)
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{
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int i;
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for(i = 0; i < WEPKEYSTORE; i++) {
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val *= 0x343fd;
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val += 0x269ec3;
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keys[i] = val >> 16;
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}
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return;
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}
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/*
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* generate one key from a string using the de facto standard
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*
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* resultant key is stored in
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* one 128 bit key: keys[0-15]
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*
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* (NOTE: I'm not sure why, but it seems that only values 0-12 are used,
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* resulting in 104 bits of keying, not 128)
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*/
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void
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wep_keygen128(char *str, u_char *keys)
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{
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MD5_CTX ctx;
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u_char buf[64];
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int i, j;
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/* repeat str until buf is full */
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j = 0;
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for(i = 0; i < 64; i++) {
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if(str[j] == 0)
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j = 0;
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buf[i] = str[j++];
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}
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MD5_Init(&ctx);
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MD5_Update(&ctx, buf, sizeof buf);
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MD5_Final(buf, &ctx);
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memcpy(keys, buf, WEPSTRONGKEYSTORE);
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for(i = 0; i < WEPSTRONGKEYSIZE; i++) {
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keys[i] = buf[i];
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}
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for(; i < WEPSTRONGKEYSTORE; i++) {
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keys[i] = 0;
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}
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return;
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}
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/*
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* generate four subkeys from a string using the defacto standard
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*
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* resultant keys are stored in
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* four 40 bit keys: keys[0-4], keys[5-9], keys[10-14] and keys[15-20]
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*/
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void
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wep_keygen40(char *str, u_char *keys)
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{
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int val, i, shift;
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/*
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* seed is generated by xor'ing in the keystring bytes
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* into the four bytes of the seed, starting at the little end
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*/
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val = 0;
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for(i = 0; str[i]; i++) {
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shift = i & 0x3;
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val ^= (str[i] << (shift * 8));
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}
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wep_seedkeygen(val, keys);
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return;
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}
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void
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wep_keyprint40(u_char *keys)
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{
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int i;
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char sepchar;
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for(i = 0; i < WEPKEYSTORE; i++) {
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sepchar = (i % WEPKEYSIZE == WEPKEYSIZE - 1) ? '\n' : ':';
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printf("%02x%c", keys[i], sepchar);
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}
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return;
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}
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void
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wep_keyprint128(u_char *keys)
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{
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int i;
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char sepchar;
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for(i = 0; i < WEPSTRONGKEYSTORE; i++) {
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sepchar = (i % WEPSTRONGKEYSIZE == WEPSTRONGKEYSIZE - 1) ? '\n' : ':';
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printf("%02x%c", keys[i], sepchar);
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}
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return;
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}
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void
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usage(char *prog)
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{
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printf("Usage: %s keystring [-s || 5 || 13]\n", prog);
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exit(1);
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}
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int
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main(int argc, char **argv)
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{
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u_char keys[WEPKEYSTORE];
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u_char strongkeys[WEPSTRONGKEYSTORE];
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char *prog, *genstr;
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int strong, ch;
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prog = argv[0];
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strong = 0;
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while((ch = getopt(argc, argv, "s")) != EOF) {
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switch(ch) {
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case 's':
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strong ++;
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break;
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default:
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usage(prog);
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}
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}
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argc -= optind;
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argv += optind;
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if(argc==2)
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if(!strcmp(argv[1],"13"))
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{
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strong++;
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argc--;
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}
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else argc--;
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if(argc != 1)
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usage(prog);
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genstr = argv[0];
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if(strong)
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{
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wep_keygen128(genstr, strongkeys);
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wep_keyprint128(strongkeys);
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}
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else
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{
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wep_keygen40(genstr, keys);
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wep_keyprint40(keys);
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}
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return 0;
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}
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