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 static char version_string[] = "vipw 1.4";
  48
  49 #include <sys/types.h>
  50 #include <sys/stat.h>
  51 #include <pwd.h>
  52 #include <stdio.h>
  53 #include <stdlib.h>
  54 #include <string.h>
  55 #include <sys/param.h>
  56 #include <sys/time.h>
  57 #include <sys/wait.h>
  58 #include <sys/resource.h>
  59 #include <sys/file.h>
  60 #include <signal.h>
  61 #include <fcntl.h>
  62 #include <errno.h>
  63 #include <err.h>
  64 #include <paths.h>
  65 #include <unistd.h>
  66
  67 #include "setpwnam.h"
  68 #include "strutils.h"
  69 #include "nls.h"
  70
  71 #ifdef HAVE_LIBSELINUX
  72 #include <selinux/selinux.h>
  73 #endif
  74
  75 #define FILENAMELEN 67
  76
  77 char *progname;
  78 enum { VIPW, VIGR };
  79 int program;
  80 char orig_file[FILENAMELEN];   /* original file /etc/passwd or /etc/group */
  81 char tmp_file[FILENAMELEN];    /* tmp file */
  82 char tmptmp_file[FILENAMELEN]; /* very tmp file */
  83
  84 void pw_error __P((char *, int, int));
  85
  86 static void
  87 copyfile(int from, int to) {
  88         int nr, nw, off;
  89         char buf[8*1024];
  90
  91         while ((nr = read(from, buf, sizeof(buf))) > 0)
  92                 for (off = 0; off < nr; nr -= nw, off += nw)
  93                         if ((nw = write(to, buf + off, nr)) < 0)
  94                           pw_error(tmp_file, 1, 1);
  95
  96         if (nr < 0)
  97           pw_error(orig_file, 1, 1);
  98 }
  99
 100
 101 static void
 102 pw_init(void) {
 103         struct rlimit rlim;
 104
 105         /* Unlimited resource limits. */
 106         rlim.rlim_cur = rlim.rlim_max = RLIM_INFINITY;
 107         (void)setrlimit(RLIMIT_CPU, &rlim);
 108         (void)setrlimit(RLIMIT_FSIZE, &rlim);
 109         (void)setrlimit(RLIMIT_STACK, &rlim);
 110         (void)setrlimit(RLIMIT_DATA, &rlim);
 111         (void)setrlimit(RLIMIT_RSS, &rlim);
 112
 113         /* Don't drop core (not really necessary, but GP's). */
 114         rlim.rlim_cur = rlim.rlim_max = 0;
 115         (void)setrlimit(RLIMIT_CORE, &rlim);
 116
 117         /* Turn off signals. */
 118         (void)signal(SIGALRM, SIG_IGN);
 119         (void)signal(SIGHUP, SIG_IGN);
 120         (void)signal(SIGINT, SIG_IGN);
 121         (void)signal(SIGPIPE, SIG_IGN);
 122         (void)signal(SIGQUIT, SIG_IGN);
 123         (void)signal(SIGTERM, SIG_IGN);
 124         (void)signal(SIGTSTP, SIG_IGN);
 125         (void)signal(SIGTTOU, SIG_IGN);
 126
 127         /* Create with exact permissions. */
 128         (void)umask(0);
 129 }
 130
 131 static int
 132 pw_lock(void) {
 133         int lockfd, fd, ret;
 134
 135         /*
 136          * If the password file doesn't exist, the system is hosed.
 137          * Might as well try to build one.  Set the close-on-exec bit so
 138          * that users can't get at the encrypted passwords while editing.
 139          * Open should allow flock'ing the file; see 4.4BSD.    XXX
 140          */
 141 #if 0 /* flock()ing is superfluous here, with the ptmp/ptmptmp system. */
 142         if (flock(lockfd, LOCK_EX|LOCK_NB)) {
 143                 if (program == VIPW)
 144                         fprintf(stderr, _("%s: the password file is busy.\n"),
 145                                 progname);
 146                 else
 147                         fprintf(stderr, _("%s: the group file is busy.\n"),
 148                                 progname);
 149                 exit(1);
 150         }
 151 #endif
 152
 153         if ((fd = open(tmptmp_file, O_WRONLY|O_CREAT, 0600)) == -1)
 154             err(EXIT_FAILURE, _("%s: open failed"), tmptmp_file);
 155
 156         ret = link(tmptmp_file, tmp_file);
 157         (void)unlink(tmptmp_file);
 158         if (ret == -1) {
 159             if (errno == EEXIST)
 160                 (void)fprintf(stderr,
 161                               _("%s: the %s file is busy (%s present)\n"),
 162                               progname,
 163                               program == VIPW ? "password" : "group",
 164                               tmp_file);
 165             else {
 166                 int errsv = errno;
 167                 (void)fprintf(stderr, _("%s: can't link %s: %s\n"), progname,
 168                               tmp_file, strerror(errsv));
 169             }
 170             exit(EXIT_FAILURE);
 171         }
 172
 173         lockfd = open(orig_file, O_RDONLY, 0);
 174
 175         if (lockfd < 0) {
 176                 (void)fprintf(stderr, "%s: %s: %s\n",
 177                     progname, orig_file, strerror(errno));
 178                 unlink(tmp_file);
 179                 exit(EXIT_FAILURE);
 180         }
 181
 182         copyfile(lockfd, fd);
 183         (void)close(lockfd);
 184         (void)close(fd);
 185         return 1;
 186 }
 187
 188 static void
 189 pw_unlock(void) {
 190         char tmp[FILENAMELEN+4];
 191
 192         sprintf(tmp, "%s%s", orig_file, ".OLD");
 193         unlink(tmp);
 194         link(orig_file, tmp);
 195
 196 #ifdef HAVE_LIBSELINUX
 197         if (is_selinux_enabled() > 0) {
 198           security_context_t passwd_context=NULL;
 199           int ret=0;
 200           if (getfilecon(orig_file,&passwd_context) < 0) {
 201             (void) fprintf(stderr,_("%s: Can't get context for %s"),progname,orig_file);
 202             pw_error(orig_file, 1, 1);
 203           }
 204           ret=setfilecon(tmp_file,passwd_context);
 205           freecon(passwd_context);
 206           if (ret!=0) {
 207             (void) fprintf(stderr,_("%s: Can't set context for %s"),progname,tmp_file);
 208             pw_error(tmp_file, 1, 1);
 209           }
 210         }
 211 #endif
 212
 213         if (rename(tmp_file, orig_file) == -1) {
 214                 int errsv = errno;
 215                 fprintf(stderr,
 216                         _("%s: can't unlock %s: %s (your changes are still in %s)\n"),
 217                         progname, orig_file, strerror(errsv), tmp_file);
 218                 exit(EXIT_FAILURE);
 219         }
 220         unlink(tmp_file);
 221 }
 222
 223
 224 static void
 225 pw_edit(int notsetuid) {
 226         int pstat;
 227         pid_t pid;
 228         char *p, *editor;
 229
 230         if (!(editor = getenv("EDITOR")))
 231                 editor = strdup(_PATH_VI); /* adia@egnatia.ee.auth.gr */
 232         if ((p = strrchr(strtok(editor," \t"), '/')) != NULL)
 233                 ++p;
 234         else
 235                 p = editor;
 236
 237         pid = fork();
 238         if (pid < 0)
 239                 err(EXIT_FAILURE, _("fork failed"));
 240
 241         if (!pid) {
 242                 if (notsetuid) {
 243                         (void)setgid(getgid());
 244                         (void)setuid(getuid());
 245                 }
 246                 execlp(editor, p, tmp_file, NULL);
 247
 248                 /* Shouldn't get here */
 249                 _exit(EXIT_FAILURE);
 250         }
 251         for (;;) {
 252             pid = waitpid(pid, &pstat, WUNTRACED);
 253             if (WIFSTOPPED(pstat)) {
 254                 /* the editor suspended, so suspend us as well */
 255                 kill(getpid(), SIGSTOP);
 256                 kill(pid, SIGCONT);
 257             } else {
 258                 break;
 259             }
 260         }
 261         if (pid == -1 || !WIFEXITED(pstat) || WEXITSTATUS(pstat) != 0)
 262                 pw_error(editor, 1, 1);
 263 }
 264
 265 void
 266 pw_error(char *name, int err, int eval) {
 267         if (err) {
 268                 int sverrno = errno;
 269
 270                 fprintf(stderr, "%s: ", progname);
 271                 if (name)
 272                         (void)fprintf(stderr, "%s: ", name);
 273                 fprintf(stderr, "%s\n", strerror(sverrno));
 274         }
 275         fprintf(stderr,
 276             _("%s: %s unchanged\n"), progname, orig_file);
 277         unlink(tmp_file);
 278         exit(eval);
 279 }
 280
 281 static void
 282 edit_file(int is_shadow)
 283 {
 284         struct stat begin, end;
 285
 286         pw_init();
 287         pw_lock();
 288
 289         if (stat(tmp_file, &begin))
 290                 pw_error(tmp_file, 1, 1);
 291
 292         pw_edit(0);
 293
 294         if (stat(tmp_file, &end))
 295                 pw_error(tmp_file, 1, 1);
 296         if (begin.st_mtime == end.st_mtime) {
 297                 (void)fprintf(stderr, _("%s: no changes made\n"), progname);
 298                 pw_error((char *)NULL, 0, 0);
 299         }
 300         /* see pw_lock() where we create the file with mode 600 */
 301         if (!is_shadow)
 302                 chmod(tmp_file, 0644);
 303         else
 304                 chmod(tmp_file, 0400);
 305         pw_unlock();
 306 }
 307
 308 int main(int argc, char *argv[]) {
 309
 310         setlocale(LC_ALL, "");
 311         bindtextdomain(PACKAGE, LOCALEDIR);
 312         textdomain(PACKAGE);
 313
 314         memset(tmp_file, '\0', FILENAMELEN);
 315         progname = (strrchr(argv[0], '/')) ? strrchr(argv[0], '/') + 1 : argv[0];
 316         if (!strcmp(progname, "vigr")) {
 317                 program = VIGR;
 318                 xstrncpy(orig_file, GROUP_FILE, sizeof(orig_file));
 319                 xstrncpy(tmp_file, GTMP_FILE, sizeof(tmp_file));
 320                 xstrncpy(tmptmp_file, GTMPTMP_FILE, sizeof(tmptmp_file));
 321         } else {
 322                 program = VIPW;
 323                 xstrncpy(orig_file, PASSWD_FILE, sizeof(orig_file));
 324                 xstrncpy(tmp_file, PTMP_FILE, sizeof(tmp_file));
 325                 xstrncpy(tmptmp_file, PTMPTMP_FILE, sizeof(tmptmp_file));
 326         }
 327
 328         if ((argc > 1) &&
 329             (!strcmp(argv[1], "-V") || !strcmp(argv[1], "--version"))) {
 330                 printf("%s\n", version_string);
 331                 exit(EXIT_SUCCESS);
 332         }
 333
 334         edit_file(0);
 335
 336         if (program == VIGR) {
 337                 strncpy(orig_file, SGROUP_FILE, FILENAMELEN-1);
 338                 strncpy(tmp_file, SGTMP_FILE, FILENAMELEN-1);
 339                 strncpy(tmptmp_file, SGTMPTMP_FILE, FILENAMELEN-1);
 340         } else {
 341                 strncpy(orig_file, SHADOW_FILE, FILENAMELEN-1);
 342                 strncpy(tmp_file, SPTMP_FILE, FILENAMELEN-1);
 343                 strncpy(tmptmp_file, SPTMPTMP_FILE, FILENAMELEN-1);
 344         }
 345
 346         if (access(orig_file, F_OK) == 0) {
 347                 char response[80];
 348
 349                 printf((program == VIGR)
 350                        ? _("You are using shadow groups on this system.\n")
 351                        : _("You are using shadow passwords on this system.\n"));
 352                 printf(_("Would you like to edit %s now [y/n]? "), orig_file);
 353
 354                 /* EOF means no */
 355                 if (fgets(response, sizeof(response), stdin)) {
 356                         if (response[0] == 'y' || response[0] == 'Y')
 357                                 edit_file(1);
 358                 }
 359         }
 360
 361         exit(EXIT_SUCCESS);
 362 }