usr/src/ucbcmd/vipw/vipw.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 /*      Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T     */
  27 /*        All Rights Reserved   */
  28
  29 /*
  30  * Portions of this source code were derived from Berkeley 4.3 BSD
  31  * under license from the Regents of the University of California.
  32  */
  33
  34 #pragma ident   "%Z%%M% %I%     %E% SMI"
  35
  36 #include <sys/types.h>
  37 #include <sys/stat.h>
  38 #include <sys/file.h>
  39 #include <sys/fcntl.h>
  40
  41 #include <stdio.h>
  42 #include <errno.h>
  43 #include <signal.h>
  44 #include <stdlib.h>
  45 #include <strings.h>
  46
  47 /*
  48  * Password file editor with locking.
  49  */
  50
  51 #define DEFAULT_EDITOR  "/usr/bin/vi"
  52
  53 static int copyfile(char *, char *);
  54 static int editfile(char *, char *, char *, time_t *);
  55 static int sanity_check(char *, time_t *, char *);
  56 static int validsh(char *);
  57
  58 char    *ptemp = "/etc/ptmp";
  59 char    *stemp = "/etc/stmp";
  60 char    *passwd = "/etc/passwd";
  61 char    *shadow = "/etc/shadow";
  62 char    buf[BUFSIZ];
  63
  64 int
  65 main(void)
  66 {
  67         int fd;
  68         FILE *ft, *fp;
  69         char *editor;
  70         int ok = 0;
  71         time_t o_mtime, n_mtime;
  72         struct stat osbuf, sbuf, oshdbuf, shdbuf;
  73         char c;
  74
  75         (void)signal(SIGINT, SIG_IGN);
  76         (void)signal(SIGQUIT, SIG_IGN);
  77         (void)signal(SIGHUP, SIG_IGN);
  78         setbuf(stderr, (char *)NULL);
  79
  80         editor = getenv("VISUAL");
  81         if (editor == 0)
  82                 editor = getenv("EDITOR");
  83         if (editor == 0)
  84                 editor = DEFAULT_EDITOR;
  85
  86         (void)umask(0077);
  87         if (stat(passwd, &osbuf) < 0) {
  88                 (void)fprintf(stderr,"vipw: can't stat passwd file.\n");
  89                 goto bad;
  90         }
  91
  92         if (copyfile(passwd, ptemp))
  93                 goto bad;
  94
  95         if (stat(ptemp, &sbuf) < 0) {
  96                 (void)fprintf(stderr,
  97                         "vipw: can't stat ptemp file, %s unchanged\n",
  98                         passwd);
  99                 goto bad;
 100         }
 101
 102         o_mtime = sbuf.st_mtime;
 103
 104         if (editfile(editor, ptemp, passwd, &n_mtime)) {
 105                 if (sanity_check(ptemp, &n_mtime, passwd))
 106                         goto bad;
 107                 if (o_mtime >= n_mtime)
 108                         goto bad;
 109         }
 110
 111         ok++;
 112         if (o_mtime < n_mtime) {
 113                 fprintf(stdout, "\nYou have modified the password file.\n");
 114                 fprintf(stdout,
 115         "Press 'e' to edit the shadow file for consistency,\n 'q' to quit: ");
 116                 if ((c = getchar()) == 'q') {
 117                         if (chmod(ptemp, (osbuf.st_mode & 0644)) < 0) {
 118                                 (void) fprintf(stderr, "vipw: %s: ", ptemp);
 119                                 perror("chmod");
 120                                 goto bad;
 121                         }
 122                         if (rename(ptemp, passwd) < 0) {
 123                                 (void) fprintf(stderr, "vipw: %s: ", ptemp);
 124                                 perror("rename");
 125                                 goto bad;
 126                         }
 127                         if (((osbuf.st_gid != sbuf.st_gid) ||
 128                                         (osbuf.st_uid != sbuf.st_uid)) &&
 129                         (chown(passwd, osbuf.st_uid, osbuf.st_gid) < 0)) {
 130                                 (void) fprintf(stderr, "vipw: %s ", ptemp);
 131                                 perror("chown");
 132                         }
 133                         goto bad;
 134                 } else if (c == 'e') {
 135                         if (stat(shadow, &oshdbuf) < 0) {
 136                                 (void) fprintf(stderr,
 137                                         "vipw: can't stat shadow file.\n");
 138                                 goto bad;
 139                         }
 140
 141                         if (copyfile(shadow, stemp))
 142                                 goto bad;
 143                         if (stat(stemp, &shdbuf) < 0) {
 144                                 (void) fprintf(stderr,
 145                                         "vipw: can't stat stmp file.\n");
 146                                 goto bad;
 147                         }
 148
 149                         if (editfile(editor, stemp, shadow, &o_mtime))
 150                                 goto bad;
 151                         ok++;
 152                         if (chmod(ptemp, (osbuf.st_mode & 0644)) < 0) {
 153                                 (void) fprintf(stderr, "vipw: %s: ", ptemp);
 154                                 perror("chmod");
 155                                 goto bad;
 156                         }
 157                         if (chmod(stemp, (oshdbuf.st_mode & 0400)) < 0) {
 158                                 (void) fprintf(stderr, "vipw: %s: ", stemp);
 159                                 perror("chmod");
 160                                 goto bad;
 161                         }
 162                         if (rename(ptemp, passwd) < 0) {
 163                                 (void) fprintf(stderr, "vipw: %s: ", ptemp);
 164                                 perror("rename");
 165                                 goto bad;
 166                         }
 167                         if (((osbuf.st_gid != sbuf.st_gid) ||
 168                                         (osbuf.st_uid != sbuf.st_uid)) &&
 169                         (chown(passwd, osbuf.st_uid, osbuf.st_gid) < 0)) {
 170                                 (void) fprintf(stderr, "vipw: %s ", ptemp);
 171                                 perror("chown");
 172                         }
 173                         if (rename(stemp, shadow) < 0) {
 174                                 (void) fprintf(stderr, "vipw: %s: ", stemp);
 175                                 perror("rename");
 176                                 goto bad;
 177                         } else if (((oshdbuf.st_gid != shdbuf.st_gid) ||
 178                                         (oshdbuf.st_uid != shdbuf.st_uid)) &&
 179                         (chown(shadow, oshdbuf.st_uid, oshdbuf.st_gid) < 0)) {
 180                                 (void) fprintf(stderr, "vipw: %s ", stemp);
 181                                 perror("chown");
 182                                 }
 183                 }
 184         }
 185 bad:
 186         (void) unlink(ptemp);
 187         (void) unlink(stemp);
 188         return (ok ? 0 : 1);
 189         /* NOTREACHED */
 190 }
 191
 192
 193 int
 194 copyfile(char *from, char *to)
 195 {
 196         int fd;
 197         FILE *fp, *ft;
 198
 199         fd = open(to, O_WRONLY|O_CREAT|O_EXCL, 0600);
 200         if (fd < 0) {
 201                 if (errno == EEXIST) {
 202                         (void) fprintf(stderr, "vipw: %s file busy\n", from);
 203                         exit(1);
 204                 }
 205                 (void) fprintf(stderr, "vipw: "); perror(to);
 206                 exit(1);
 207         }
 208         ft = fdopen(fd, "w");
 209         if (ft == NULL) {
 210                 (void) fprintf(stderr, "vipw: "); perror(to);
 211                 return( 1 );
 212         }
 213         fp = fopen(from, "r");
 214         if (fp == NULL) {
 215                 (void) fprintf(stderr, "vipw: "); perror(from);
 216                 return( 1 );
 217         }
 218         while (fgets(buf, sizeof (buf) - 1, fp) != NULL)
 219                 fputs(buf, ft);
 220         (void) fclose(ft);
 221         (void) fclose(fp);
 222         return( 0 );
 223 }
 224
 225 int
 226 editfile(char *editor, char *temp, char *orig, time_t *mtime)
 227 {
 228         (void)sprintf(buf, "%s %s", editor, temp);
 229         if (system(buf) == 0) {
 230                 return (sanity_check(temp, mtime, orig));
 231         }
 232         return(1);
 233 }
 234
 235
 236 int
 237 validsh(char *rootsh)
 238 {
 239
 240         char    *sh, *getusershell();
 241         int     ret = 0;
 242
 243         setusershell();
 244         while((sh = getusershell()) != NULL ) {
 245                 if( strcmp( rootsh, sh) == 0 ) {
 246                         ret = 1;
 247                         break;
 248                 }
 249         }
 250         endusershell();
 251         return(ret);
 252 }
 253
 254 /*
 255  * sanity checks
 256  * return 0 if ok, 1 otherwise
 257  */
 258 int
 259 sanity_check(char *temp, time_t *mtime, char *orig)
 260 {
 261         int i, ok = 0;
 262         FILE *ft;
 263         struct stat sbuf, statbuf;
 264         char *ldir;
 265         int isshadow = 0;
 266
 267         if (!strcmp(orig, shadow))
 268                 isshadow = 1;
 269
 270         /* sanity checks */
 271         if (stat(temp, &sbuf) < 0) {
 272                 (void)fprintf(stderr,
 273                     "vipw: can't stat %s file, %s unchanged\n",
 274                     temp, orig);
 275                 return(1);
 276         }
 277         *mtime = sbuf.st_mtime;
 278         if (sbuf.st_size == 0) {
 279                 (void)fprintf(stderr, "vipw: bad %s file, %s unchanged\n",
 280                     temp, orig);
 281                 return(1);
 282         }
 283         ft = fopen(temp, "r");
 284         if (ft == NULL) {
 285                 (void)fprintf(stderr,
 286                     "vipw: can't reopen %s file, %s unchanged\n",
 287                     temp, orig);
 288                 return(1);
 289         }
 290
 291         while (fgets(buf, sizeof (buf) - 1, ft) != NULL) {
 292                 char *cp;
 293
 294                 cp = index(buf, '\n');
 295                 if (cp == 0)
 296                         continue;       /* ??? allow very long lines
 297                                          * and passwd files that do
 298                                          * not end in '\n' ???
 299                                          */
 300                 *cp = '\0';
 301
 302                 cp = index(buf, ':');
 303                 if (cp == 0)            /* lines without colon
 304                                          * separated fields
 305                                          */
 306                         continue;
 307                 *cp = '\0';
 308
 309                 if (strcmp(buf, "root"))
 310                         continue;
 311
 312                 /* root password */
 313                 *cp = ':';
 314                 cp = index(cp + 1, ':');
 315                 if (cp == 0)
 316                         goto bad_root;
 317
 318                 /* root uid for password */
 319                 if (!isshadow)
 320                         if (atoi(cp + 1) != 0) {
 321
 322                                 (void)fprintf(stderr, "root UID != 0:\n%s\n",
 323                                     buf);
 324                                 break;
 325                         }
 326                 /* root uid for passwd and sp_lstchg for shadow */
 327                 cp = index(cp + 1, ':');
 328                 if (cp == 0)
 329                         goto bad_root;
 330
 331                 /* root's gid for passwd and sp_min for shadow*/
 332                 cp = index(cp + 1, ':');
 333                 if (cp == 0)
 334                         goto bad_root;
 335
 336                 /* root's gecos for passwd and sp_max for shadow*/
 337                 cp = index(cp + 1, ':');
 338                 if (isshadow) {
 339                         for (i=0; i<3; i++)
 340                                 if ((cp = index(cp + 1, ':')) == 0)
 341                                         goto bad_root;
 342                 } else {
 343                         if (cp == 0) {
 344 bad_root:               (void)fprintf(stderr,
 345                                     "Missing fields in root entry:\n%s\n", buf);
 346                                 break;
 347                         }
 348                 }
 349                 if (!isshadow) {
 350                         /* root's login directory */
 351                         ldir = ++cp;
 352                         cp = index(cp, ':');
 353                         if (cp == 0)
 354                                 goto bad_root;
 355                         *cp = '\0';
 356                         if (stat(ldir, &statbuf) < 0) {
 357                                 *cp = ':';
 358                                 (void) fprintf(stderr,
 359                                     "root login dir doesn't exist:\n%s\n",
 360                                     buf);
 361                                 break;
 362                         } else if (!S_ISDIR(statbuf.st_mode)) {
 363                                 *cp = ':';
 364                                 (void) fprintf(stderr,
 365                                     "root login dir is not a directory:\n%s\n",
 366                                     buf);
 367                                 break;
 368                         }
 369
 370                         *cp = ':';
 371                         /* root's login shell */
 372                         ++cp;
 373                         if (*cp && ! validsh(cp)) {
 374                                 (void)fprintf(stderr,
 375                                     "Invalid root shell:\n%s\n", buf);
 376                                 break;
 377                         }
 378                 }
 379
 380                 ok++;
 381         }
 382         (void)fclose(ft);
 383         if (ok)
 384                 return(0);
 385         else {
 386                 (void)fprintf(stderr,
 387                     "vipw: you mangled the %s file, %s unchanged\n",
 388                     temp, orig);
 389                 return(1);
 390         }
 391 }