source: trunk-3.0/examples/auth/crackcheck/crackcheck.c@ 101

#include <memory.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#include <crack.h>

void usage(char *command) {
        char *c, *comm;

        comm = command;
        while ((c = strrchr(comm, '/')) != NULL) {
                comm = c + 1;
        }

        fprintf(stderr, "Usage: %s [-c] [-s] [-d <dictionary>]\n\n", comm);
        fprintf(stderr, "     -c    enables NT like complexity checks\n");
        fprintf(stderr, "     -d <dictionary file>    for cracklib\n");
        fprintf(stderr, "     -s    simple check use NT like checks ONLY\n\n");
        fprintf(stderr, "The password is read via stdin.\n\n");
        exit(-1);
}

int complexity(char* passwd)
{
        /* TG 26.10.2005
         * check password for complexity like MS Windows NT 
         */

        int c_upper = 0;
        int c_lower = 0;
        int c_digit = 0;
        int c_punct = 0;
        int c_tot = 0;
        int i, len;

        if (!passwd) goto fail;
        len = strlen(passwd);

        for (i = 0; i < len; i++) {

                if (c_tot >= 3) break;

                if (isupper(passwd[i])) {
                        if (!c_upper) {
                                c_upper = 1;
                                c_tot += 1;
                        }
                        continue;
                }
                if (islower(passwd[i])) {
                        if (!c_lower) {
                                c_lower = 1;
                                c_tot += 1;
                        }
                        continue;
                }
                if (isdigit(passwd[i])) {
                        if (!c_digit) {
                                c_digit = 1;
                                c_tot += 1;
                        }
                        continue;
                }
                if (ispunct(passwd[i])) {
                        if (!c_punct) {
                                c_punct = 1;
                                c_tot += 1;
                        }
                        continue;
                }
        }

        if ((c_tot) < 3) goto fail;
        return 0;

fail:
        fprintf(stderr, "ERR Complexity check failed\n\n");
        return -4;
}

int main(int argc, char **argv) {
        extern char *optarg;
        int c, ret, complex_check = 0, simplex_check = 0;

        char f[256];
        char *dictionary = NULL;
        char *password;
        char *reply;

        while ( (c = getopt(argc, argv, "d:cs")) != EOF){
                switch(c) {
                case 'd':
                        dictionary = strdup(optarg);
                        break;
                case 'c':
                        complex_check = 1;
                        break;
                case 's':
                        complex_check = 1;
                        simplex_check = 1;
                        break;
                default:
                        usage(argv[0]);
                }
        }

        if (!simplex_check && dictionary == NULL) {
                fprintf(stderr, "ERR - Missing cracklib dictionary\n\n");
                usage(argv[0]);
        } 

        fflush(stdin);
        password = fgets(f, sizeof(f), stdin);

        if (password == NULL) {
                fprintf(stderr, "ERR - Failed to read password\n\n");
                exit(-2);
        }

        if (complex_check) {
                ret = complexity(password);
                if (ret) {
                        exit(ret);
                }
        }

        if (simplex_check) {
                exit(0);
        }

        reply = FascistCheck(password, dictionary);
        if (reply != NULL) {
                fprintf(stderr, "ERR - %s\n\n", reply);
                exit(-3);
        }

        exit(0);
}