1 /* 2 * Copyright (c) 2010-2014, Simon Schubert <2@0x2c.org>. 3 * Copyright (c) 2008 The DragonFly Project. All rights reserved. 4 * 5 * This code is derived from software contributed to The DragonFly Project 6 * by Simon Schubert <2@0x2c.org>. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in 16 * the documentation and/or other materials provided with the 17 * distribution. 18 * 3. Neither the name of The DragonFly Project nor the names of its 19 * contributors may be used to endorse or promote products derived 20 * from this software without specific, prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 23 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 24 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 25 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 26 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 28 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 29 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 30 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 31 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 32 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 /* 37 * This binary is setuid root. Use extreme caution when touching 38 * user-supplied information. Keep the root window as small as possible. 39 */ 40 41 #include <sys/param.h> 42 #include <sys/stat.h> 43 44 #include <errno.h> 45 #include <fcntl.h> 46 #include <grp.h> 47 #include <paths.h> 48 #include <pwd.h> 49 #include <stdio.h> 50 #include <syslog.h> 51 #include <unistd.h> 52 53 #include "dma.h" 54 55 56 static void 57 logfail(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 84 int 85 main(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 f, maildirfd; 93 94 openlog("dma-mbox-create", 0, LOG_MAIL); 95 96 errno = 0; 97 gr = getgrnam(DMA_GROUP); 98 if (!gr) 99 logfail(EX_CONFIG, "cannot find dma group `%s'", DMA_GROUP); 100 101 mail_gid = gr->gr_gid; 102 103 if (setgid(mail_gid) != 0) 104 logfail(EX_NOPERM, "cannot set gid to %d (%s)", mail_gid, DMA_GROUP); 105 if (getegid() != mail_gid) 106 logfail(EX_NOPERM, "cannot set gid to %d (%s), still at %d", mail_gid, DMA_GROUP, getegid()); 107 108 /* 109 * We take exactly one argument: the username. 110 */ 111 if (argc != 2) { 112 errno = 0; 113 logfail(EX_USAGE, "no arguments"); 114 } 115 user = argv[1]; 116 117 syslog(LOG_NOTICE, "creating mbox for `%s'", user); 118 119 /* the username may not contain a pathname separator */ 120 if (strchr(user, '/')) { 121 errno = 0; 122 logfail(EX_DATAERR, "path separator in username `%s'", user); 123 exit(1); 124 } 125 126 /* verify the user exists */ 127 errno = 0; 128 pw = getpwnam(user); 129 if (!pw) 130 logfail(EX_NOUSER, "cannot find user `%s'", user); 131 132 maildirfd = open(_PATH_MAILDIR, O_RDONLY); 133 if (maildirfd < 0) 134 logfail(EX_NOINPUT, "cannot open maildir %s", _PATH_MAILDIR); 135 136 user_uid = pw->pw_uid; 137 138 f = openat(maildirfd, user, O_RDONLY|O_CREAT|O_NOFOLLOW, 0600); 139 if (f < 0) 140 logfail(EX_NOINPUT, "cannot open mbox `%s'", user); 141 142 if (fchown(f, user_uid, mail_gid)) 143 logfail(EX_OSERR, "cannot change owner of mbox `%s'", user); 144 145 if (fchmod(f, 0620)) 146 logfail(EX_OSERR, "cannot change permissions of mbox `%s'", 147 user); 148 149 /* file should be present with the right owner and permissions */ 150 151 syslog(LOG_NOTICE, "successfully created mbox for `%s'", user); 152 153 return (0); 154 } 155