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      1 /*	$NetBSD: pam_passwd.c,v 1.7 2021/09/10 21:52:18 rillig Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2002 Networks Associates Technologies, Inc.
      5  * All rights reserved.
      6  *
      7  * This software was developed for the FreeBSD Project by ThinkSec AS and
      8  * NAI Labs, the Security Research Division of Network Associates, Inc.
      9  * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
     10  * DARPA CHATS research program.
     11  *
     12  * Redistribution and use in source and binary forms, with or without
     13  * modification, are permitted provided that the following conditions
     14  * are met:
     15  * 1. Redistributions of source code must retain the above copyright
     16  *    notice, this list of conditions and the following disclaimer.
     17  * 2. Redistributions in binary form must reproduce the above copyright
     18  *    notice, this list of conditions and the following disclaimer in the
     19  *    documentation and/or other materials provided with the distribution.
     20  * 3. The name of the author may not be used to endorse or promote
     21  *    products derived from this software without specific prior written
     22  *    permission.
     23  *
     24  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     34  * SUCH DAMAGE.
     35  */
     36 
     37 #include <sys/cdefs.h>
     38 #ifdef __FreeBSD__
     39 __FBSDID("$FreeBSD: src/usr.bin/passwd/passwd.c,v 1.23 2003/04/18 21:27:09 nectar Exp $");
     40 #else
     41 __RCSID("$NetBSD: pam_passwd.c,v 1.7 2021/09/10 21:52:18 rillig Exp $");
     42 #endif
     43 
     44 #include <sys/param.h>
     45 
     46 #include <err.h>
     47 #include <pwd.h>
     48 #include <stdio.h>
     49 #include <stdlib.h>
     50 #include <syslog.h>
     51 #include <unistd.h>
     52 
     53 #include "extern.h"
     54 
     55 #include <security/pam_appl.h>
     56 #include <security/openpam.h>
     57 
     58 static pam_handle_t *pamh;
     59 static struct pam_conv pamc = {
     60 	openpam_ttyconv,
     61 	NULL
     62 };
     63 
     64 #define	pam_check(msg)							\
     65 do {									\
     66 	if (pam_err != PAM_SUCCESS) {					\
     67 		warnx("%s: %s", (msg), pam_strerror(pamh, pam_err));	\
     68 		goto end;						\
     69 	}								\
     70 } while (0)
     71 
     72 void
     73 pwpam_process(const char *username, int argc, char **argv)
     74 {
     75 	int ch, pam_err;
     76 	char hostname[MAXHOSTNAMELEN + 1];
     77 
     78 	/* details about the invoking user for logging */
     79 	const uid_t i_uid = getuid();
     80 	const struct passwd *const i_pwd = getpwuid(i_uid);
     81 	const char *const i_username = (i_pwd && i_pwd->pw_name)
     82 		? i_pwd->pw_name : "(null)";
     83 
     84 	while ((ch = getopt(argc, argv, "")) != -1) {
     85 		switch (ch) {
     86 		default:
     87 			usage();
     88 			/* NOTREACHED */
     89 		}
     90 	}
     91 
     92 	argc -= optind;
     93 	argv += optind;
     94 
     95 	switch (argc) {
     96 	case 0:
     97 		/* username already provided */
     98 		break;
     99 	case 1:
    100 		username = argv[0];
    101 		break;
    102 	default:
    103 		usage();
    104 		/* NOTREACHED */
    105 	}
    106 
    107 	(void)printf("Changing password for %s.\n", username);
    108 
    109 	/* initialize PAM -- always use the program name "passwd" */
    110 	pam_err = pam_start("passwd", username, &pamc, &pamh);
    111 	if (pam_err != PAM_SUCCESS)
    112 		errx(1, "unable to start PAM session: %s",
    113 		    pam_strerror(NULL, pam_err));
    114 
    115 	pam_err = pam_set_item(pamh, PAM_TTY, ttyname(STDERR_FILENO));
    116 	pam_check("unable to set TTY");
    117 
    118 	(void)gethostname(hostname, sizeof hostname);
    119 	pam_err = pam_set_item(pamh, PAM_RHOST, hostname);
    120 	pam_check("unable to set RHOST");
    121 
    122 	pam_err = pam_set_item(pamh, PAM_RUSER, getlogin());
    123 	pam_check("unable to set RUSER");
    124 
    125 	/* set new password */
    126 	pam_err = pam_chauthtok(pamh, 0);
    127 	if (pam_err != PAM_SUCCESS) {
    128 		if (pam_err == PAM_PERM_DENIED) {
    129 			syslog(LOG_AUTH | LOG_NOTICE,
    130 			       "user %s (UID %lu) failed to change the "
    131 			       "PAM authentication token of user %s: %s",
    132 			       i_username, (unsigned long)i_uid, username,
    133 			       pam_strerror(pamh, pam_err));
    134 		}
    135 		printf("Unable to change auth token: %s\n",
    136 		    pam_strerror(pamh, pam_err));
    137 	} else {
    138 		syslog(LOG_AUTH | LOG_INFO,
    139 		       "user %s (UID %lu) successfully changed the "
    140 		       "PAM authentication token of user %s",
    141 		       i_username, (unsigned long)i_uid, username);
    142 	}
    143 
    144  end:
    145 	pam_end(pamh, pam_err);
    146 	if (pam_err == PAM_SUCCESS)
    147 		return;
    148 	exit(1);
    149 }
    150