1 /* $OpenBSD: chpass.c,v 1.37 2009/10/27 23:59:36 deraadt Exp $ */ 2 /* $NetBSD: chpass.c,v 1.8 1996/05/15 21:50:43 jtc Exp $ */ 3 4 /*- 5 * Copyright (c) 1988, 1993, 1994 6 * The Regents of the University of California. All rights reserved. 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 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <sys/param.h> 34 #include <sys/resource.h> 35 #include <sys/stat.h> 36 #include <sys/time.h> 37 #include <sys/uio.h> 38 39 #include <err.h> 40 #include <errno.h> 41 #include <fcntl.h> 42 #include <paths.h> 43 #include <pwd.h> 44 #include <signal.h> 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include <string.h> 48 #include <unistd.h> 49 #include <util.h> 50 51 #include "chpass.h" 52 53 extern char *__progname; 54 55 enum { NEWSH, LOADENTRY, EDITENTRY } op; 56 uid_t uid; 57 #ifdef YP 58 int use_yp; 59 int force_yp = 0; 60 #endif 61 62 void baduser(void); 63 void kbintr(int); 64 void usage(void); 65 66 int 67 main(int argc, char *argv[]) 68 { 69 struct passwd *pw = NULL, *opw = NULL, lpw; 70 int i, ch, pfd, tfd, dfd; 71 char *tz, *arg = NULL; 72 sigset_t fullset; 73 74 #ifdef YP 75 use_yp = _yp_check(NULL); 76 #endif 77 /* We need to use the system timezone for date conversions. */ 78 if ((tz = getenv("TZ")) != NULL) { 79 unsetenv("TZ"); 80 tzset(); 81 setenv("TZ", tz, 1); 82 } 83 84 op = EDITENTRY; 85 while ((ch = getopt(argc, argv, "a:s:ly")) != -1) 86 switch(ch) { 87 case 'a': 88 op = LOADENTRY; 89 arg = optarg; 90 break; 91 case 's': 92 op = NEWSH; 93 arg = optarg; 94 break; 95 #ifdef YP 96 case 'l': 97 use_yp = 0; 98 break; 99 case 'y': 100 if (!use_yp) { 101 warnx("YP not in use."); 102 usage(); 103 } 104 force_yp = 1; 105 break; 106 #endif 107 case '?': 108 default: 109 usage(); 110 } 111 argc -= optind; 112 argv += optind; 113 114 #ifdef YP 115 if (op == LOADENTRY && use_yp) 116 errx(1, "cannot load using YP, use -l to load local."); 117 #endif 118 uid = getuid(); 119 120 if (op == EDITENTRY || op == NEWSH) 121 switch(argc) { 122 case 0: 123 pw = getpwuid(uid); 124 #ifdef YP 125 if (pw && !force_yp) 126 use_yp = 0; 127 else if (use_yp) 128 pw = ypgetpwuid(uid); 129 #endif /* YP */ 130 if (!pw) 131 errx(1, "unknown user: uid %u", uid); 132 break; 133 case 1: 134 pw = getpwnam(*argv); 135 #ifdef YP 136 if (pw && !force_yp) 137 use_yp = 0; 138 else if (use_yp) 139 pw = ypgetpwnam(*argv); 140 #endif /* YP */ 141 if (!pw) 142 errx(1, "unknown user: %s", *argv); 143 if (uid && uid != pw->pw_uid) 144 baduser(); 145 break; 146 default: 147 usage(); 148 } 149 150 if (op == LOADENTRY) { 151 if (argc != 0) 152 errx(1, "option -a does not accept user argument"); 153 if (uid) 154 baduser(); 155 pw = &lpw; 156 if (!pw_scan(arg, pw, NULL)) 157 exit(1); 158 opw = getpwnam(pw->pw_name); 159 } 160 if (opw == NULL && (opw = pw_dup(pw)) == NULL) 161 err(1, NULL); 162 163 /* Edit the user passwd information if requested. */ 164 if (op == EDITENTRY) { 165 char tempname[] = _PATH_VARTMP "pw.XXXXXXXXXX"; 166 int edit_status; 167 168 if ((pw = pw_dup(pw)) == NULL) 169 pw_error(NULL, 1, 1); 170 dfd = mkstemp(tempname); 171 if (dfd == -1 || fcntl(dfd, F_SETFD, 1) == -1) 172 pw_error(tempname, 1, 1); 173 display(tempname, dfd, pw); 174 edit_status = edit(tempname, pw); 175 close(dfd); 176 unlink(tempname); 177 178 switch (edit_status) { 179 case EDIT_OK: 180 break; 181 case EDIT_NOCHANGE: 182 pw_error(NULL, 0, 0); 183 break; 184 case EDIT_ERROR: 185 default: 186 pw_error(tempname, 1, 1); 187 break; 188 } 189 } 190 191 if (op == NEWSH) { 192 /* protect p_shell -- it thinks NULL is /bin/sh */ 193 if (!arg[0]) 194 usage(); 195 if (p_shell(arg, pw, NULL)) 196 pw_error(NULL, 0, 1); 197 } 198 199 /* Drop user's real uid and block all signals to avoid a DoS. */ 200 setuid(0); 201 sigfillset(&fullset); 202 sigdelset(&fullset, SIGINT); 203 sigprocmask(SIG_BLOCK, &fullset, NULL); 204 205 /* Get the passwd lock file and open the passwd file for reading. */ 206 pw_init(); 207 for (i = 1; (tfd = pw_lock(0)) == -1; i++) { 208 if (i == 4) 209 (void)fputs("Attempting lock password file, " 210 "please wait or press ^C to abort", stderr); 211 (void)signal(SIGINT, kbintr); 212 if (i % 16 == 0) 213 fputc('.', stderr); 214 usleep(250000); 215 (void)signal(SIGINT, SIG_IGN); 216 } 217 if (i >= 4) 218 fputc('\n', stderr); 219 pfd = open(_PATH_MASTERPASSWD, O_RDONLY, 0); 220 if (pfd == -1 || fcntl(pfd, F_SETFD, 1) == -1) 221 pw_error(_PATH_MASTERPASSWD, 1, 1); 222 223 #ifdef YP 224 if (use_yp) { 225 if (pw_yp(pw, uid)) 226 pw_error(NULL, 0, 1); 227 else { 228 pw_abort(); 229 exit(0); 230 } 231 } else 232 #endif /* YP */ 233 { 234 /* Copy the passwd file to the lock file, updating pw. */ 235 pw_copy(pfd, tfd, pw, opw); 236 237 /* If username changed we need to rebuild the entire db. */ 238 arg = !strcmp(opw->pw_name, pw->pw_name) ? pw->pw_name : NULL; 239 240 /* Now finish the passwd file update. */ 241 if (pw_mkdb(arg, 0) == -1) 242 pw_error(NULL, 0, 1); 243 } 244 245 exit(0); 246 } 247 248 void 249 baduser(void) 250 { 251 252 errx(1, "%s", strerror(EACCES)); 253 } 254 255 /* ARGSUSED */ 256 void 257 kbintr(int signo) 258 { 259 struct iovec iv[5]; 260 261 iv[0].iov_base = "\n"; 262 iv[0].iov_len = 1; 263 iv[1].iov_base = __progname; 264 iv[1].iov_len = strlen(__progname); 265 iv[2].iov_base = ": "; 266 iv[2].iov_len = 2; 267 iv[3].iov_base = _PATH_MASTERPASSWD; 268 iv[3].iov_len = sizeof(_PATH_MASTERPASSWD) - 1; 269 iv[4].iov_base = " unchanged\n"; 270 iv[4].iov_len = 11; 271 writev(STDERR_FILENO, iv, 5); 272 273 _exit(1); 274 } 275 276 void 277 usage(void) 278 { 279 280 #ifdef YP 281 (void)fprintf(stderr, 282 "usage: %s [-l%s] [-s newshell] [user]\n", 283 __progname, use_yp ? "y" : ""); 284 (void)fprintf(stderr, 285 " %s [-l] -a list\n", __progname); 286 #else 287 (void)fprintf(stderr, "usage: %s [-s newshell] [user]\n", __progname); 288 (void)fprintf(stderr, " %s -a list\n", __progname); 289 #endif 290 exit(1); 291 } 292