libexec/revnetgroup/parse_netgroup.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-3-Clause
   3  *
   4  * Copyright (c) 1992, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Rick Macklem at The University of Guelph.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 /*
  36  * This is a specially hacked-up version of getnetgrent.c used to parse
  37  * data from the stored hash table of netgroup info rather than from a
  38  * file. It's used mainly for the parse_netgroup() function. All the YP
  39  * stuff and file support has been stripped out since it isn't needed.
  40  */
  41
  42 #include <stdio.h>
  43 #include <string.h>
  44 #include <strings.h>
  45 #include <stdlib.h>
  46 #include <unistd.h>
  47 #include "hash.h"
  48
  49 /*
  50  * Static Variables and functions used by setnetgrent(), getnetgrent() and
  51  * __endnetgrent().
  52  * There are two linked lists:
  53  * - linelist is just used by setnetgrent() to parse the net group file via.
  54  *   parse_netgrp()
  55  * - netgrp is the list of entries for the current netgroup
  56  */
  57 struct linelist {
  58         struct linelist *l_next;        /* Chain ptr. */
  59         int             l_parsed;       /* Flag for cycles */
  60         char            *l_groupname;   /* Name of netgroup */
  61         char            *l_line;        /* Netgroup entrie(s) to be parsed */
  62 };
  63
  64 struct netgrp {
  65         struct netgrp   *ng_next;       /* Chain ptr */
  66         char            *ng_str[3];     /* Field pointers, see below */
  67 };
  68 #define NG_HOST         0       /* Host name */
  69 #define NG_USER         1       /* User name */
  70 #define NG_DOM          2       /* and Domain name */
  71
  72 static struct linelist  *linehead = (struct linelist *)0;
  73 static struct netgrp    *nextgrp = (struct netgrp *)0;
  74 static struct {
  75         struct netgrp   *gr;
  76         char            *grname;
  77 } grouphead = {
  78         (struct netgrp *)0,
  79         (char *)0,
  80 };
  81 static int parse_netgrp(char *group);
  82 static struct linelist *read_for_group(char *group);
  83 extern struct group_entry *gtable[];
  84
  85 /*
  86  * setnetgrent()
  87  * Parse the netgroup file looking for the netgroup and build the list
  88  * of netgrp structures. Let parse_netgrp() and read_for_group() do
  89  * most of the work.
  90  */
  91 void
  92 __setnetgrent(char *group)
  93 {
  94         /* Sanity check */
  95
  96         if (group == NULL || !strlen(group))
  97                 return;
  98
  99         if (grouphead.gr == (struct netgrp *)0 ||
 100                 strcmp(group, grouphead.grname)) {
 101                 __endnetgrent();
 102                 if (parse_netgrp(group))
 103                         __endnetgrent();
 104                 else {
 105                         grouphead.grname = (char *)
 106                                 malloc(strlen(group) + 1);
 107                         strcpy(grouphead.grname, group);
 108                 }
 109         }
 110         nextgrp = grouphead.gr;
 111 }
 112
 113 /*
 114  * Get the next netgroup off the list.
 115  */
 116 int
 117 __getnetgrent(char **hostp, char **userp, char **domp)
 118 {
 119         if (nextgrp) {
 120                 *hostp = nextgrp->ng_str[NG_HOST];
 121                 *userp = nextgrp->ng_str[NG_USER];
 122                 *domp = nextgrp->ng_str[NG_DOM];
 123                 nextgrp = nextgrp->ng_next;
 124                 return (1);
 125         }
 126         return (0);
 127 }
 128
 129 /*
 130  * __endnetgrent() - cleanup
 131  */
 132 void
 133 __endnetgrent(void)
 134 {
 135         struct linelist *lp, *olp;
 136         struct netgrp *gp, *ogp;
 137
 138         lp = linehead;
 139         while (lp) {
 140                 olp = lp;
 141                 lp = lp->l_next;
 142                 free(olp->l_groupname);
 143                 free(olp->l_line);
 144                 free((char *)olp);
 145         }
 146         linehead = (struct linelist *)0;
 147         if (grouphead.grname) {
 148                 free(grouphead.grname);
 149                 grouphead.grname = (char *)0;
 150         }
 151         gp = grouphead.gr;
 152         while (gp) {
 153                 ogp = gp;
 154                 gp = gp->ng_next;
 155                 if (ogp->ng_str[NG_HOST])
 156                         free(ogp->ng_str[NG_HOST]);
 157                 if (ogp->ng_str[NG_USER])
 158                         free(ogp->ng_str[NG_USER]);
 159                 if (ogp->ng_str[NG_DOM])
 160                         free(ogp->ng_str[NG_DOM]);
 161                 free((char *)ogp);
 162         }
 163         grouphead.gr = (struct netgrp *)0;
 164 }
 165
 166 /*
 167  * Parse the netgroup file setting up the linked lists.
 168  */
 169 static int
 170 parse_netgrp(char *group)
 171 {
 172         char *spos, *epos;
 173         int len, strpos;
 174 #ifdef DEBUG
 175         int fields;
 176 #endif
 177         char *pos, *gpos;
 178         struct netgrp *grp;
 179         struct linelist *lp = linehead;
 180
 181         /*
 182          * First, see if the line has already been read in.
 183          */
 184         while (lp) {
 185                 if (!strcmp(group, lp->l_groupname))
 186                         break;
 187                 lp = lp->l_next;
 188         }
 189         if (lp == (struct linelist *)0 &&
 190             (lp = read_for_group(group)) == (struct linelist *)0)
 191                 return (1);
 192         if (lp->l_parsed) {
 193 #ifdef DEBUG
 194                 /*
 195                  * This error message is largely superfluous since the
 196                  * code handles the error condition successfully, and
 197                  * spewing it out from inside libc can actually hose
 198                  * certain programs.
 199                  */
 200                 warnx("cycle in netgroup %s", lp->l_groupname);
 201 #endif
 202                 return (1);
 203         } else
 204                 lp->l_parsed = 1;
 205         pos = lp->l_line;
 206         /* Watch for null pointer dereferences, dammit! */
 207         while (pos != NULL && *pos != '\0') {
 208                 if (*pos == '(') {
 209                         grp = (struct netgrp *)malloc(sizeof (struct netgrp));
 210                         bzero((char *)grp, sizeof (struct netgrp));
 211                         grp->ng_next = grouphead.gr;
 212                         grouphead.gr = grp;
 213                         pos++;
 214                         gpos = strsep(&pos, ")");
 215 #ifdef DEBUG
 216                         fields = 0;
 217 #endif
 218                         for (strpos = 0; strpos < 3; strpos++) {
 219                                 if ((spos = strsep(&gpos, ","))) {
 220 #ifdef DEBUG
 221                                         fields++;
 222 #endif
 223                                         while (*spos == ' ' || *spos == '\t')
 224                                                 spos++;
 225                                         if ((epos = strpbrk(spos, " \t"))) {
 226                                                 *epos = '\0';
 227                                                 len = epos - spos;
 228                                         } else
 229                                                 len = strlen(spos);
 230                                         if (len > 0) {
 231                                                 grp->ng_str[strpos] =  (char *)
 232                                                         malloc(len + 1);
 233                                                 bcopy(spos, grp->ng_str[strpos],
 234                                                         len + 1);
 235                                         }
 236                                 } else {
 237                                         /*
 238                                          * All other systems I've tested
 239                                          * return NULL for empty netgroup
 240                                          * fields. It's up to user programs
 241                                          * to handle the NULLs appropriately.
 242                                          */
 243                                         grp->ng_str[strpos] = NULL;
 244                                 }
 245                         }
 246 #ifdef DEBUG
 247                         /*
 248                          * Note: on other platforms, malformed netgroup
 249                          * entries are not normally flagged. While we
 250                          * can catch bad entries and report them, we should
 251                          * stay silent by default for compatibility's sake.
 252                          */
 253                         if (fields < 3)
 254                                         warnx("bad entry (%s%s%s%s%s) in netgroup \"%s\"",
 255                                                 grp->ng_str[NG_HOST] == NULL ? "" : grp->ng_str[NG_HOST],
 256                                                 grp->ng_str[NG_USER] == NULL ? "" : ",",
 257                                                 grp->ng_str[NG_USER] == NULL ? "" : grp->ng_str[NG_USER],
 258                                                 grp->ng_str[NG_DOM] == NULL ? "" : ",",
 259                                                 grp->ng_str[NG_DOM] == NULL ? "" : grp->ng_str[NG_DOM],
 260                                                 lp->l_groupname);
 261 #endif
 262                 } else {
 263                         spos = strsep(&pos, ", \t");
 264                         if (parse_netgrp(spos))
 265                                 continue;
 266                 }
 267                 /* Watch for null pointer dereferences, dammit! */
 268                 if (pos != NULL)
 269                         while (*pos == ' ' || *pos == ',' || *pos == '\t')
 270                                 pos++;
 271         }
 272         return (0);
 273 }
 274
 275 /*
 276  * Read the netgroup file and save lines until the line for the netgroup
 277  * is found. Return 1 if eof is encountered.
 278  */
 279 static struct linelist *
 280 read_for_group(char *group)
 281 {
 282         char *pos, *spos, *linep = NULL, *olinep = NULL;
 283         int len, olen;
 284         int cont;
 285         struct linelist *lp;
 286         char line[LINSIZ + 1];
 287         char *data = NULL;
 288
 289         data = lookup (gtable, group);
 290         sprintf(line, "%s %s", group, data);
 291         pos = (char *)&line;
 292 #ifdef CANT_HAPPEN
 293         if (*pos == '#')
 294                 continue;
 295 #endif
 296         while (*pos == ' ' || *pos == '\t')
 297                 pos++;
 298         spos = pos;
 299         while (*pos != ' ' && *pos != '\t' && *pos != '\n' &&
 300                 *pos != '\0')
 301                 pos++;
 302         len = pos - spos;
 303         while (*pos == ' ' || *pos == '\t')
 304                 pos++;
 305         if (*pos != '\n' && *pos != '\0') {
 306                 lp = (struct linelist *)malloc(sizeof (*lp));
 307                 lp->l_parsed = 0;
 308                 lp->l_groupname = (char *)malloc(len + 1);
 309                 bcopy(spos, lp->l_groupname, len);
 310                 *(lp->l_groupname + len) = '\0';
 311                 len = strlen(pos);
 312                 olen = 0;
 313                         /*
 314                          * Loop around handling line continuations.
 315                          */
 316                         do {
 317                                 if (*(pos + len - 1) == '\n')
 318                                         len--;
 319                                 if (*(pos + len - 1) == '\\') {
 320                                         len--;
 321                                         cont = 1;
 322                                 } else
 323                                         cont = 0;
 324                                 if (len > 0) {
 325                                         linep = (char *)malloc(olen + len + 1);
 326                                         if (olen > 0) {
 327                                                 bcopy(olinep, linep, olen);
 328                                                 free(olinep);
 329                                         }
 330                                         bcopy(pos, linep + olen, len);
 331                                         olen += len;
 332                                         *(linep + olen) = '\0';
 333                                         olinep = linep;
 334                                 }
 335 #ifdef CANT_HAPPEN
 336                                 if (cont) {
 337                                         if (fgets(line, LINSIZ, netf)) {
 338                                                 pos = line;
 339                                                 len = strlen(pos);
 340                                         } else
 341                                                 cont = 0;
 342                                 }
 343 #endif
 344                         } while (cont);
 345                 lp->l_line = linep;
 346                 lp->l_next = linehead;
 347                 linehead = lp;
 348 #ifdef CANT_HAPPEN
 349                 /*
 350                  * If this is the one we wanted, we are done.
 351                  */
 352                 if (!strcmp(lp->l_groupname, group))
 353 #endif
 354                         return (lp);
 355         }
 356         return ((struct linelist *)0);
 357 }