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 <string.h> 51 #include <syslog.h> 52 #include <unistd.h> 53 54 #include "dma.h" 55 56 57 static void 58 logfail(int exitcode, const char *fmt, ...) 59 { 60 int oerrno = errno; 61 va_list ap; 62 char outs[1024]; 63 64 outs[0] = 0; 65 if (fmt != NULL) { 66 va_start(ap, fmt); 67 vsnprintf(outs, sizeof(outs), fmt, ap); 68 va_end(ap); 69 } 70 71 errno = oerrno; 72 if (*outs != 0) 73 syslog(LOG_ERR, errno ? "%s: %m" : "%s", outs); 74 else 75 syslog(LOG_ERR, errno ? "%m" : "unknown error"); 76 77 exit(exitcode); 78 } 79 80 /* 81 * Create a mbox in /var/mail for a given user, or make sure 82 * the permissions are correct for dma. 83 */ 84 85 int 86 main(int argc, char **argv) 87 { 88 const char *user; 89 struct passwd *pw; 90 struct group *gr; 91 uid_t user_uid; 92 gid_t mail_gid; 93 int f, maildirfd; 94 95 openlog("dma-mbox-create", 0, LOG_MAIL); 96 97 errno = 0; 98 gr = getgrnam(DMA_GROUP); 99 if (!gr) 100 logfail(EX_CONFIG, "cannot find dma group `%s'", DMA_GROUP); 101 102 mail_gid = gr->gr_gid; 103 104 if (setgid(mail_gid) != 0) 105 logfail(EX_NOPERM, "cannot set gid to %d (%s)", mail_gid, DMA_GROUP); 106 if (getegid() != mail_gid) 107 logfail(EX_NOPERM, "cannot set gid to %d (%s), still at %d", mail_gid, DMA_GROUP, getegid()); 108 109 /* 110 * We take exactly one argument: the username. 111 */ 112 if (argc != 2) { 113 errno = 0; 114 logfail(EX_USAGE, "no arguments"); 115 } 116 user = argv[1]; 117 118 syslog(LOG_NOTICE, "creating mbox for `%s'", user); 119 120 /* the username may not contain a pathname separator */ 121 if (strchr(user, '/')) { 122 errno = 0; 123 logfail(EX_DATAERR, "path separator in username `%s'", user); 124 exit(1); 125 } 126 127 /* verify the user exists */ 128 errno = 0; 129 pw = getpwnam(user); 130 if (!pw) 131 logfail(EX_NOUSER, "cannot find user `%s'", user); 132 133 maildirfd = open(_PATH_MAILDIR, O_RDONLY); 134 if (maildirfd < 0) 135 logfail(EX_NOINPUT, "cannot open maildir %s", _PATH_MAILDIR); 136 137 user_uid = pw->pw_uid; 138 139 f = openat(maildirfd, user, O_RDONLY|O_CREAT|O_NOFOLLOW, 0600); 140 if (f < 0) 141 logfail(EX_NOINPUT, "cannot open mbox `%s'", user); 142 143 if (fchown(f, user_uid, mail_gid)) 144 logfail(EX_OSERR, "cannot change owner of mbox `%s'", user); 145 146 if (fchmod(f, 0620)) 147 logfail(EX_OSERR, "cannot change permissions of mbox `%s'", 148 user); 149 150 /* file should be present with the right owner and permissions */ 151 152 syslog(LOG_NOTICE, "successfully created mbox for `%s'", user); 153 154 return (0); 155 } 156