/*	$NetBSD: kpasswd-generator.c,v 1.2 2017/01/28 21:31:45 christos Exp $	*/

/*
 * Copyright (c) 2000 - 2004 Kungliga Tekniska Högskolan
 * (Royal Institute of Technology, Stockholm, Sweden).
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "kpasswd_locl.h"

__RCSID("$NetBSD: kpasswd-generator.c,v 1.2 2017/01/28 21:31:45 christos Exp $");

static unsigned
read_words(const char *filename, char ***ret_w)
{
    unsigned n, alloc;
    FILE *f;
    char buf[256];
    char **w = NULL;

    f = fopen(filename, "r");
    if (f == NULL)
	err(1, "cannot open %s", filename);
    alloc = n = 0;
    while (fgets(buf, sizeof(buf), f) != NULL) {
	buf[strcspn(buf, "\r\n")] = '\0';
	if (n >= alloc) {
	    alloc += 16;
	    w = erealloc(w, alloc * sizeof(char *));
	}
	w[n++] = estrdup(buf);
    }
    *ret_w = w;
    if (n == 0)
	errx(1, "%s is an empty file, no words to try", filename);
    fclose(f);
    return n;
}

static int
nop_prompter(krb5_context context,
	     void *data,
	     const char *name,
	     const char *banner,
	     int num_prompts,
	     krb5_prompt prompts[])
{
    return 0;
}

static void
generate_requests(const char *filename, unsigned nreq)
{
    krb5_context context;
    krb5_error_code ret;
    int i;
    char **words;
    unsigned nwords, k;

    ret = krb5_init_context(&context);
    if (ret)
	errx (1, "krb5_init_context failed: %d", ret);

    nwords = read_words(filename, &words);

    for (i = 0; i < nreq; ++i) {
	char *name = words[rand() % nwords];
	krb5_get_init_creds_opt *opt;
	krb5_creds cred;
	krb5_principal principal;
	int result_code;
	krb5_data result_code_string, result_string;
	char *old_pwd, *new_pwd;
	int aret;

	krb5_get_init_creds_opt_alloc(context, &opt);
	krb5_get_init_creds_opt_set_tkt_life (opt, 300);
	krb5_get_init_creds_opt_set_forwardable (opt, FALSE);
	krb5_get_init_creds_opt_set_proxiable (opt, FALSE);

	ret = krb5_parse_name(context, name, &principal);
	if (ret)
	    krb5_err(context, 1, ret, "krb5_parse_name %s", name);

	aret = asprintf(&old_pwd, "%s", name);
	if (aret == -1)
	    krb5_errx(context, 1, "out of memory");
	aret = asprintf(&new_pwd, "%s2", name);
	if (aret == -1)
	    krb5_errx(context, 1, "out of memory");

	ret = krb5_get_init_creds_password(context,
					   &cred,
					   principal,
					   old_pwd,
					   nop_prompter,
					   NULL,
					   0,
					   "kadmin/changepw",
					   opt);
	if (ret == KRB5KRB_AP_ERR_BAD_INTEGRITY
	    || ret == KRB5KRB_AP_ERR_MODIFIED) {
	    char *tmp;

	    tmp = new_pwd;
	    new_pwd = old_pwd;
	    old_pwd = tmp;

            ret = krb5_get_init_creds_password(context,
                                               &cred,
                                               principal,
                                               old_pwd,
                                               nop_prompter,
                                               NULL,
                                               0,
                                               "kadmin/changepw",
                                               opt);
	}
	if (ret)
	    krb5_err(context, 1, ret, "krb5_get_init_creds_password");

	krb5_free_principal(context, principal);


        ret = krb5_set_password(context,
                                &cred,
                                new_pwd,
                                NULL,
                                &result_code,
                                &result_code_string,
                                &result_string);
	if (ret)
	    krb5_err(context, 1, ret, "krb5_change_password");

	free(old_pwd);
	free(new_pwd);
	krb5_free_cred_contents(context, &cred);
	krb5_get_init_creds_opt_free(context, opt);
    }

    for (k = 0; k < nwords; k++)
        free(words[k]);
    free(words);
}

static int version_flag	= 0;
static int help_flag	= 0;

static struct getargs args[] = {
    { "version", 	0,   arg_flag, &version_flag, NULL, NULL },
    { "help",		0,   arg_flag, &help_flag,    NULL, NULL }
};

static void
usage(int ret)
{
    arg_printusage(args,
		   sizeof(args)/sizeof(*args),
		   NULL,
		   "file [number]");
    exit (ret);
}

int
main(int argc, char **argv)
{
    int optidx = 0;
    int nreq;
    char *end;

    setprogname(argv[0]);
    if(getarg(args, sizeof(args) / sizeof(args[0]), argc, argv, &optidx))
	usage(1);
    if (help_flag)
	usage (0);
    if (version_flag) {
	print_version(NULL);
	return 0;
    }
    argc -= optidx;
    argv += optidx;

    if (argc != 2)
	usage (1);
    srand (0);
    nreq = strtol(argv[1], &end, 0);
    if (argv[1] == end || *end != '\0')
	usage (1);
    generate_requests(argv[0], nreq);
    return 0;
}
