/*
* Copyright (c) 2010-2014, Simon Schubert <2@0x2c.org>.
* Copyright (c) 2008 The DragonFly Project. All rights reserved.
*
* This code is derived from software contributed to The DragonFly Project
* by Simon Schubert <2@0x2c.org>.
*
* 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 DragonFly Project 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 COPYRIGHT HOLDERS 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
* COPYRIGHT HOLDERS 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.
*/
/*
* This binary is setuid root. Use extreme caution when touching
* user-supplied information. Keep the root window as small as possible.
*/
#ifdef __FreeBSD__
#define USE_CAPSICUM 1
#endif
#include <sys/param.h>
#if USE_CAPSICUM
#include <sys/capsicum.h>
#endif
#include <sys/stat.h>
#include <capsicum_helpers.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <grp.h>
#include <paths.h>
#include <pwd.h>
#include <stdio.h>
#include <syslog.h>
#include <unistd.h>
#include "dma.h"
static void
logfail(int exitcode, const char *fmt, ...)
{
int oerrno = errno;
va_list ap;
char outs[1024];
outs[0] = 0;
if (fmt != NULL) {
va_start(ap, fmt);
vsnprintf(outs, sizeof(outs), fmt, ap);
va_end(ap);
}
errno = oerrno;
if (*outs != 0)
syslog(LOG_ERR, errno ? "%s: %m" : "%s", outs);
else
syslog(LOG_ERR, errno ? "%m" : "unknown error");
exit(exitcode);
}
/*
* Create a mbox in /var/mail for a given user, or make sure
* the permissions are correct for dma.
*/
int
main(int argc, char **argv)
{
#if USE_CAPSICUM
cap_rights_t rights;
#endif
const char *user;
struct passwd *pw;
struct group *gr;
uid_t user_uid;
gid_t mail_gid;
int f, maildirfd;
/*
* Open log fd now for capability sandbox.
*/
openlog("dma-mbox-create", LOG_NDELAY, LOG_MAIL);
errno = 0;
gr = getgrnam(DMA_GROUP);
if (!gr)
logfail(EX_CONFIG, "cannot find dma group `%s'", DMA_GROUP);
mail_gid = gr->gr_gid;
if (setgid(mail_gid) != 0)
logfail(EX_NOPERM, "cannot set gid to %d (%s)", mail_gid, DMA_GROUP);
if (getegid() != mail_gid)
logfail(EX_NOPERM, "cannot set gid to %d (%s), still at %d", mail_gid, DMA_GROUP, getegid());
/*
* We take exactly one argument: the username.
*/
if (argc != 2) {
errno = 0;
logfail(EX_USAGE, "no arguments");
}
user = argv[1];
syslog(LOG_NOTICE, "creating mbox for `%s'", user);
/* the username may not contain a pathname separator */
if (strchr(user, '/')) {
errno = 0;
logfail(EX_DATAERR, "path separator in username `%s'", user);
exit(1);
}
/* verify the user exists */
errno = 0;
pw = getpwnam(user);
if (!pw)
logfail(EX_NOUSER, "cannot find user `%s'", user);
maildirfd = open(_PATH_MAILDIR, O_RDONLY);
if (maildirfd < 0)
logfail(EX_NOINPUT, "cannot open maildir %s", _PATH_MAILDIR);
/*
* Cache NLS data, for strerror, for err(3), before entering capability
* mode.
*/
caph_cache_catpages();
/*
* Cache local time before entering Capsicum capability sandbox.
*/
caph_cache_tzdata();
#if USE_CAPSICUM
cap_rights_init(&rights, CAP_CREATE, CAP_FCHMOD, CAP_FCHOWN,
CAP_LOOKUP, CAP_READ);
if (cap_rights_limit(maildirfd, &rights) < 0 && errno != ENOSYS)
err(EX_OSERR, "can't limit maildirfd rights");
/* Enter Capsicum capability sandbox */
if (cap_enter() < 0 && errno != ENOSYS)
err(EX_OSERR, "cap_enter");
#endif
user_uid = pw->pw_uid;
f = openat(maildirfd, user, O_RDONLY|O_CREAT|O_NOFOLLOW, 0600);
if (f < 0)
logfail(EX_NOINPUT, "cannot open mbox `%s'", user);
if (fchown(f, user_uid, mail_gid))
logfail(EX_OSERR, "cannot change owner of mbox `%s'", user);
if (fchmod(f, 0620))
logfail(EX_OSERR, "cannot change permissions of mbox `%s'",
user);
/* file should be present with the right owner and permissions */
syslog(LOG_NOTICE, "successfully created mbox for `%s'", user);
return (0);
}
