meillo@0: /*  MasqMail
meillo@0:     Copyright (C) 2000 Oliver Kurth
meillo@174:     Copyright (C) 2010 markus schnalke <meillo@marmaro.de>
meillo@0: 
meillo@0:     This program is free software; you can redistribute it and/or modify
meillo@0:     it under the terms of the GNU General Public License as published by
meillo@0:     the Free Software Foundation; either version 2 of the License, or
meillo@0:     (at your option) any later version.
meillo@0: 
meillo@0:     This program is distributed in the hope that it will be useful,
meillo@0:     but WITHOUT ANY WARRANTY; without even the implied warranty of
meillo@0:     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
meillo@0:     GNU General Public License for more details.
meillo@0: 
meillo@0:     You should have received a copy of the GNU General Public License
meillo@0:     along with this program; if not, write to the Free Software
meillo@0:     Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
meillo@0: */
meillo@0: 
meillo@0: #include <pwd.h>
meillo@0: #include <grp.h>
meillo@0: 
meillo@15: #include "masqmail.h"
meillo@15: 
meillo@0: /* is there really no function in libc for this? */
meillo@10: gboolean
meillo@10: is_ingroup(uid_t uid, gid_t gid)
meillo@0: {
meillo@10: 	struct group *grent = getgrgid(gid);
meillo@84: 	struct passwd *pwent = getpwuid(uid);
meillo@84: 	char *entry;
meillo@84: 	int i = 0;
meillo@0: 
meillo@84: 	if (!grent) {
meillo@84: 		return FALSE;
meillo@84: 	}
meillo@84: 	if (!pwent) {
meillo@84: 		return FALSE;
meillo@84: 	}
meillo@84: 	/* check primary group */
meillo@84: 	if (pwent->pw_gid == gid) {
meillo@84: 		return TRUE;
meillo@84: 	}
meillo@84: 	/* check secondary groups */
meillo@84: 	while ((entry = grent->gr_mem[i++])) {
meillo@84: 		if (strcmp(pwent->pw_name, entry) == 0)
meillo@84: 			return TRUE;
meillo@10: 	}
meillo@10: 	return FALSE;
meillo@0: }
meillo@0: 
meillo@10: gboolean
meillo@10: is_privileged_user(uid_t uid)
meillo@0: {
meillo@87: 	/* uncomment these lines if you need the `uucp' group to be trusted too
meillo@87: 	struct group* grent = getgrnam("uucp");
meillo@87: 
meillo@87: 	if (is_ingroup(uid, grent->gr_gid)) {
meillo@87: 		return TRUE;
meillo@87: 	}
meillo@87: 	*/
meillo@87: 
meillo@10: 	return (uid == 0) || (uid == conf.mail_uid) || (is_ingroup(uid, conf.mail_gid));
meillo@0: }
meillo@0: 
meillo@10: void
meillo@10: set_euidgid(gint uid, gint gid, uid_t * old_uid, gid_t * old_gid)
meillo@0: {
meillo@10: 	if (old_uid)
meillo@10: 		*old_uid = geteuid();
meillo@10: 	if (old_gid)
meillo@10: 		*old_gid = getegid();
meillo@0: 
meillo@10: 	seteuid(0);
meillo@0: 
meillo@10: 	if (setegid(gid) != 0) {
meillo@10: 		logwrite(LOG_ALERT, "could not change gid to %d: %s\n", gid, strerror(errno));
meillo@10: 		exit(EXIT_FAILURE);
meillo@10: 	}
meillo@10: 	if (seteuid(uid) != 0) {
meillo@10: 		logwrite(LOG_ALERT, "could not change uid to %d: %s\n", uid, strerror(errno));
meillo@10: 		exit(EXIT_FAILURE);
meillo@10: 	}
meillo@0: }
meillo@0: 
meillo@10: void
meillo@10: set_identity(uid_t old_uid, gchar * task_name)
meillo@0: {
meillo@10: 	if (!conf.run_as_user) {
meillo@10: 		if (!is_privileged_user(old_uid)) {
meillo@10: 			fprintf(stderr, "must be root, %s or in group %s for %s.\n", DEF_MAIL_USER, DEF_MAIL_GROUP, task_name);
meillo@10: 			exit(EXIT_FAILURE);
meillo@10: 		}
meillo@0: 
meillo@10: 		set_euidgid(conf.mail_uid, conf.mail_gid, NULL, NULL);
meillo@10: 	}
meillo@0: }