login-utils/vipw.c

   1 /*
   2  * Copyright (c) 1987 Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  * Updated Thu Oct 12 09:56:55 1995 by faith@cs.unc.edu with security
  34  * patches from Zefram <A.Main@dcs.warwick.ac.uk>
  35  *
  36  * Updated Thu Nov  9 21:58:53 1995 by Martin Schulze
  37  * <joey@finlandia.infodrom.north.de>.  Support for vigr.
  38  *
  39  * Martin Schulze's patches adapted to Util-Linux by Nicolai Langfeldt.
  40  *
  41  * 1999-02-22 Arkadiusz Mi¶kiewicz <misiek@pld.ORG.PL>
  42  * - added Native Language Support
  43  * Sun Mar 21 1999 - Arnaldo Carvalho de Melo <acme@conectiva.com.br>
  44  * - fixed strerr(errno) in gettext calls
  45  */
  46
  47 /*
  48  * This command is deprecated.  The utility is in maintenance mode,
  49  * meaning we keep them in source tree for backward compatibility
  50  * only.  Do not waste time making this command better, unless the
  51  * fix is about security or other very critical issue.
  52  *
  53  * See Documentation/deprecated.txt for more information.
  54  */
  55
  56 #include <errno.h>
  57 #include <fcntl.h>
  58 #include <paths.h>
  59 #include <pwd.h>
  60 #include <shadow.h>
  61 #include <signal.h>
  62 #include <stdio.h>
  63 #include <stdlib.h>
  64 #include <string.h>
  65 #include <sys/file.h>
  66 #include <sys/param.h>
  67 #include <sys/resource.h>
  68 #include <sys/stat.h>
  69 #include <sys/time.h>
  70 #include <sys/types.h>
  71 #include <sys/wait.h>
  72 #include <unistd.h>
  73
  74 #include "c.h"
  75 #include "closestream.h"
  76 #include "nls.h"
  77 #include "setpwnam.h"
  78 #include "strutils.h"
  79 #include "xalloc.h"
  80
  81 #ifdef HAVE_LIBSELINUX
  82 # include <selinux/selinux.h>
  83 #endif
  84
  85 #define FILENAMELEN 67
  86
  87 enum {
  88         VIPW,
  89         VIGR
  90 };
  91 int program;
  92 char orig_file[FILENAMELEN];    /* original file /etc/passwd or /etc/group */
  93 char *tmp_file;                 /* tmp file */
  94
  95 void pw_error __P((char *, int, int));
  96
  97 static void copyfile(int from, int to)
  98 {
  99         int nr, nw, off;
 100         char buf[8 * 1024];
 101
 102         while ((nr = read(from, buf, sizeof(buf))) > 0)
 103                 for (off = 0; off < nr; nr -= nw, off += nw)
 104                         if ((nw = write(to, buf + off, nr)) < 0)
 105                                 pw_error(tmp_file, 1, 1);
 106
 107         if (nr < 0)
 108                 pw_error(orig_file, 1, 1);
 109 }
 110
 111 static void pw_init(void)
 112 {
 113         struct rlimit rlim;
 114
 115         /* Unlimited resource limits. */
 116         rlim.rlim_cur = rlim.rlim_max = RLIM_INFINITY;
 117         (void)setrlimit(RLIMIT_CPU, &rlim);
 118         (void)setrlimit(RLIMIT_FSIZE, &rlim);
 119         (void)setrlimit(RLIMIT_STACK, &rlim);
 120         (void)setrlimit(RLIMIT_DATA, &rlim);
 121         (void)setrlimit(RLIMIT_RSS, &rlim);
 122
 123         /* Don't drop core (not really necessary, but GP's). */
 124         rlim.rlim_cur = rlim.rlim_max = 0;
 125         (void)setrlimit(RLIMIT_CORE, &rlim);
 126
 127         /* Turn off signals. */
 128         (void)signal(SIGALRM, SIG_IGN);
 129         (void)signal(SIGHUP, SIG_IGN);
 130         (void)signal(SIGINT, SIG_IGN);
 131         (void)signal(SIGPIPE, SIG_IGN);
 132         (void)signal(SIGQUIT, SIG_IGN);
 133         (void)signal(SIGTERM, SIG_IGN);
 134         (void)signal(SIGTSTP, SIG_IGN);
 135         (void)signal(SIGTTOU, SIG_IGN);
 136
 137         /* Create with exact permissions. */
 138         (void)umask(0);
 139 }
 140
 141 static FILE * pw_tmpfile(int lockfd)
 142 {
 143         FILE *fd;
 144         char *tmpname = NULL;
 145
 146         if ((fd = xfmkstemp(&tmpname)) == NULL) {
 147                 ulckpwdf();
 148                 err(EXIT_FAILURE, _("can't open temporary file"));
 149         }
 150
 151         copyfile(lockfd, fileno(fd));
 152         tmp_file = tmpname;
 153         return fd;
 154 }
 155
 156 static void pw_write(void)
 157 {
 158         char tmp[FILENAMELEN + 4];
 159
 160         sprintf(tmp, "%s%s", orig_file, ".OLD");
 161         unlink(tmp);
 162
 163         if (link(orig_file, tmp))
 164                 warn(_("%s: create a link to %s failed"), orig_file, tmp);
 165
 166 #ifdef HAVE_LIBSELINUX
 167         if (is_selinux_enabled() > 0) {
 168                 security_context_t passwd_context = NULL;
 169                 int ret = 0;
 170                 if (getfilecon(orig_file, &passwd_context) < 0) {
 171                         warnx(_("Can't get context for %s"), orig_file);
 172                         pw_error(orig_file, 1, 1);
 173                 }
 174                 ret = setfilecon(tmp_file, passwd_context);
 175                 freecon(passwd_context);
 176                 if (ret != 0) {
 177                         warnx(_("Can't set context for %s"), tmp_file);
 178                         pw_error(tmp_file, 1, 1);
 179                 }
 180         }
 181 #endif
 182
 183         if (rename(tmp_file, orig_file) == -1) {
 184                 int errsv = errno;
 185                 errx(EXIT_FAILURE,
 186                      ("cannot write %s: %s (your changes are still in %s)"),
 187                      orig_file, strerror(errsv), tmp_file);
 188         }
 189         unlink(tmp_file);
 190         free(tmp_file);
 191 }
 192
 193 static void pw_edit(int notsetuid)
 194 {
 195         int pstat;
 196         pid_t pid;
 197         char *p, *editor, *tk;
 198
 199         editor = getenv("EDITOR");
 200         editor = xstrdup(editor ? editor : _PATH_VI);
 201
 202         tk = strtok(editor, " \t");
 203         if (tk && (p = strrchr(tk, '/')) != NULL)
 204                 ++p;
 205         else
 206                 p = editor;
 207
 208         pid = fork();
 209         if (pid < 0)
 210                 err(EXIT_FAILURE, _("fork failed"));
 211
 212         if (!pid) {
 213                 if (notsetuid) {
 214                         (void)setgid(getgid());
 215                         (void)setuid(getuid());
 216                 }
 217                 execlp(editor, p, tmp_file, NULL);
 218                 /* Shouldn't get here */
 219                 _exit(EXIT_FAILURE);
 220         }
 221         for (;;) {
 222                 pid = waitpid(pid, &pstat, WUNTRACED);
 223                 if (WIFSTOPPED(pstat)) {
 224                         /* the editor suspended, so suspend us as well */
 225                         kill(getpid(), SIGSTOP);
 226                         kill(pid, SIGCONT);
 227                 } else {
 228                         break;
 229                 }
 230         }
 231         if (pid == -1 || !WIFEXITED(pstat) || WEXITSTATUS(pstat) != 0)
 232                 pw_error(editor, 1, 1);
 233
 234         free(editor);
 235 }
 236
 237 void pw_error(char *name, int err, int eval)
 238 {
 239         if (err) {
 240                 if (name)
 241                         warn("%s: ", name);
 242                 else
 243                         warn(NULL);
 244         }
 245         warnx(_("%s unchanged"), orig_file);
 246         unlink(tmp_file);
 247         ulckpwdf();
 248         exit(eval);
 249 }
 250
 251 static void edit_file(int is_shadow)
 252 {
 253         struct stat begin, end;
 254         int passwd_file, ch_ret;
 255         FILE *tmp_fd;
 256
 257         pw_init();
 258
 259         /* acquire exclusive lock */
 260         if (lckpwdf() < 0)
 261                 err(EXIT_FAILURE, _("cannot get lock"));
 262
 263         passwd_file = open(orig_file, O_RDONLY, 0);
 264         if (passwd_file < 0)
 265                 err(EXIT_FAILURE, "%s: %s", _("cannot open file"), orig_file);
 266         tmp_fd = pw_tmpfile(passwd_file);
 267
 268         if (fstat(fileno(tmp_fd), &begin))
 269                 pw_error(tmp_file, 1, 1);
 270
 271         pw_edit(0);
 272
 273         if (fstat(fileno(tmp_fd), &end))
 274                 pw_error(tmp_file, 1, 1);
 275         if (begin.st_mtime == end.st_mtime) {
 276                 warnx(_("no changes made"));
 277                 pw_error((char *)NULL, 0, 0);
 278         }
 279         /* pw_tmpfile() will create the file with mode 600 */
 280         if (!is_shadow)
 281                 ch_ret = fchmod(fileno(tmp_fd), 0644);
 282         else
 283                 ch_ret = fchmod(fileno(tmp_fd), 0400);
 284         if (ch_ret < 0)
 285                 err(EXIT_FAILURE, "%s: %s", _("cannot chmod file"), orig_file);
 286         if (close_stream(tmp_fd) != 0)
 287                 err(EXIT_FAILURE, _("write error"));
 288         pw_write();
 289         close(passwd_file);
 290         ulckpwdf();
 291 }
 292
 293 int main(int argc, char *argv[])
 294 {
 295         setlocale(LC_ALL, "");
 296         bindtextdomain(PACKAGE, LOCALEDIR);
 297         textdomain(PACKAGE);
 298         atexit(close_stdout);
 299
 300         if (!strcmp(program_invocation_short_name, "vigr")) {
 301                 program = VIGR;
 302                 xstrncpy(orig_file, GROUP_FILE, sizeof(orig_file));
 303         } else {
 304                 program = VIPW;
 305                 xstrncpy(orig_file, PASSWD_FILE, sizeof(orig_file));
 306         }
 307
 308         if ((argc > 1) &&
 309             (!strcmp(argv[1], "-V") || !strcmp(argv[1], "--version"))) {
 310                 printf(UTIL_LINUX_VERSION);
 311                 exit(EXIT_SUCCESS);
 312         }
 313
 314         edit_file(0);
 315
 316         if (program == VIGR) {
 317                 strncpy(orig_file, SGROUP_FILE, FILENAMELEN - 1);
 318         } else {
 319                 strncpy(orig_file, SHADOW_FILE, FILENAMELEN - 1);
 320         }
 321
 322         if (access(orig_file, F_OK) == 0) {
 323                 char response[80];
 324
 325                 printf((program == VIGR)
 326                        ? _("You are using shadow groups on this system.\n")
 327                        : _("You are using shadow passwords on this system.\n"));
 328                 /* TRANSLATORS: this program uses for y and n rpmatch(3),
 329                  * which means they can be translated. */
 330                 printf(_("Would you like to edit %s now [y/n]? "), orig_file);
 331
 332                 if (fgets(response, sizeof(response), stdin)) {
 333                         if (rpmatch(response) == 1)
 334                                 edit_file(1);
 335                 }
 336         }
 337         exit(EXIT_SUCCESS);
 338 }