1235679Sadrian/*
2235679Sadrian * Copyright (c) 2010-2014, Simon Schubert <2@0x2c.org>.
3235679Sadrian * Copyright (c) 2008 The DragonFly Project.  All rights reserved.
4235679Sadrian *
5235679Sadrian * This code is derived from software contributed to The DragonFly Project
6235679Sadrian * by Simon Schubert <2@0x2c.org>.
7235679Sadrian *
8235679Sadrian * Redistribution and use in source and binary forms, with or without
9235679Sadrian * modification, are permitted provided that the following conditions
10235679Sadrian * are met:
11235679Sadrian *
12235679Sadrian * 1. Redistributions of source code must retain the above copyright
13235679Sadrian *    notice, this list of conditions and the following disclaimer.
14235679Sadrian * 2. Redistributions in binary form must reproduce the above copyright
15235679Sadrian *    notice, this list of conditions and the following disclaimer in
16235679Sadrian *    the documentation and/or other materials provided with the
17235679Sadrian *    distribution.
18235679Sadrian * 3. Neither the name of The DragonFly Project nor the names of its
19235679Sadrian *    contributors may be used to endorse or promote products derived
20235679Sadrian *    from this software without specific, prior written permission.
21235679Sadrian *
22235679Sadrian * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23235679Sadrian * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24235679Sadrian * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
25235679Sadrian * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
26235679Sadrian * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
27235679Sadrian * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
28235679Sadrian * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
29235679Sadrian * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
30235679Sadrian * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
31235679Sadrian * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
32235679Sadrian * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33235679Sadrian * SUCH DAMAGE.
34235679Sadrian */
35235679Sadrian
36235679Sadrian/*
37235679Sadrian * This binary is setuid root.  Use extreme caution when touching
38235679Sadrian * user-supplied information.  Keep the root window as small as possible.
39235679Sadrian */
40235679Sadrian
41235679Sadrian#include <sys/param.h>
42235679Sadrian#include <sys/stat.h>
43235679Sadrian
44235679Sadrian#include <errno.h>
45235679Sadrian#include <fcntl.h>
46235679Sadrian#include <grp.h>
47235679Sadrian#include <paths.h>
48235679Sadrian#include <pwd.h>
49235679Sadrian#include <stdio.h>
50235679Sadrian#include <syslog.h>
51235679Sadrian#include <unistd.h>
52235679Sadrian
53235679Sadrian#include "dma.h"
54235679Sadrian
55235679Sadrian
56static void
57logfail(int exitcode, const char *fmt, ...)
58{
59	int oerrno = errno;
60	va_list ap;
61	char outs[1024];
62
63	outs[0] = 0;
64	if (fmt != NULL) {
65		va_start(ap, fmt);
66		vsnprintf(outs, sizeof(outs), fmt, ap);
67		va_end(ap);
68	}
69
70	errno = oerrno;
71	if (*outs != 0)
72		syslog(LOG_ERR, errno ? "%s: %m" : "%s", outs);
73	else
74		syslog(LOG_ERR, errno ? "%m" : "unknown error");
75
76	exit(exitcode);
77}
78
79/*
80 * Create a mbox in /var/mail for a given user, or make sure
81 * the permissions are correct for dma.
82 */
83
84int
85main(int argc, char **argv)
86{
87	const char *user;
88	struct passwd *pw;
89	struct group *gr;
90	uid_t user_uid;
91	gid_t mail_gid;
92	int error;
93	char fn[PATH_MAX+1];
94	int f;
95
96	openlog("dma-mbox-create", 0, LOG_MAIL);
97
98	errno = 0;
99	gr = getgrnam(DMA_GROUP);
100	if (!gr)
101		logfail(EX_CONFIG, "cannot find dma group `%s'", DMA_GROUP);
102
103	mail_gid = gr->gr_gid;
104
105	if (setgid(mail_gid) != 0)
106		logfail(EX_NOPERM, "cannot set gid to %d (%s)", mail_gid, DMA_GROUP);
107	if (getegid() != mail_gid)
108		logfail(EX_NOPERM, "cannot set gid to %d (%s), still at %d", mail_gid, DMA_GROUP, getegid());
109
110	/*
111	 * We take exactly one argument: the username.
112	 */
113	if (argc != 2) {
114		errno = 0;
115		logfail(EX_USAGE, "no arguments");
116	}
117	user = argv[1];
118
119	syslog(LOG_NOTICE, "creating mbox for `%s'", user);
120
121	/* the username may not contain a pathname separator */
122	if (strchr(user, '/')) {
123		errno = 0;
124		logfail(EX_DATAERR, "path separator in username `%s'", user);
125		exit(1);
126	}
127
128	/* verify the user exists */
129	errno = 0;
130	pw = getpwnam(user);
131	if (!pw)
132		logfail(EX_NOUSER, "cannot find user `%s'", user);
133
134	user_uid = pw->pw_uid;
135
136	error = snprintf(fn, sizeof(fn), "%s/%s", _PATH_MAILDIR, user);
137	if (error < 0 || (size_t)error >= sizeof(fn)) {
138		if (error >= 0) {
139			errno = 0;
140			logfail(EX_USAGE, "mbox path too long");
141		}
142		logfail(EX_CANTCREAT, "cannot build mbox path for `%s/%s'", _PATH_MAILDIR, user);
143	}
144
145	f = open(fn, O_RDONLY|O_CREAT|O_NOFOLLOW, 0600);
146	if (f < 0)
147		logfail(EX_NOINPUT, "cannt open mbox `%s'", fn);
148
149	if (fchown(f, user_uid, mail_gid))
150		logfail(EX_OSERR, "cannot change owner of mbox `%s'", fn);
151
152	if (fchmod(f, 0620))
153		logfail(EX_OSERR, "cannot change permissions of mbox `%s'", fn);
154
155	/* file should be present with the right owner and permissions */
156
157	syslog(LOG_NOTICE, "successfully created mbox for `%s'", user);
158
159	return (0);
160}
161