groupaccess.c

   1 /* $OpenBSD: groupaccess.c,v 1.13 2008/07/04 03:44:59 djm Exp $ */
   2 /*
   3  * Copyright (c) 2001 Kevin Steves.  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  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "includes.h"
  27
  28 #include <sys/types.h>
  29 #include <sys/param.h>
  30
  31 #include <grp.h>
  32 #include <unistd.h>
  33 #include <stdarg.h>
  34 #include <string.h>
  35
  36 #include "xmalloc.h"
  37 #include "groupaccess.h"
  38 #include "match.h"
  39 #include "log.h"
  40
  41 static int ngroups;
  42 static char **groups_byname;
  43
  44 /*
  45  * Initialize group access list for user with primary (base) and
  46  * supplementary groups.  Return the number of groups in the list.
  47  */
  48 int
  49 ga_init(const char *user, gid_t base)
  50 {
  51         gid_t *groups_bygid;
  52         int i, j;
  53         struct group *gr;
  54
  55         if (ngroups > 0)
  56                 ga_free();
  57
  58         ngroups = NGROUPS_MAX;
  59 #if defined(HAVE_SYSCONF) && defined(_SC_NGROUPS_MAX)
  60         ngroups = MAX(NGROUPS_MAX, sysconf(_SC_NGROUPS_MAX));
  61 #endif
  62
  63         groups_bygid = xcalloc(ngroups, sizeof(*groups_bygid));
  64         groups_byname = xcalloc(ngroups, sizeof(*groups_byname));
  65
  66         if (getgrouplist(user, base, groups_bygid, &ngroups) == -1)
  67                 logit("getgrouplist: groups list too small");
  68         for (i = 0, j = 0; i < ngroups; i++)
  69                 if ((gr = getgrgid(groups_bygid[i])) != NULL)
  70                         groups_byname[j++] = xstrdup(gr->gr_name);
  71         xfree(groups_bygid);
  72         return (ngroups = j);
  73 }
  74
  75 /*
  76  * Return 1 if one of user's groups is contained in groups.
  77  * Return 0 otherwise.  Use match_pattern() for string comparison.
  78  */
  79 int
  80 ga_match(char * const *groups, int n)
  81 {
  82         int i, j;
  83
  84         for (i = 0; i < ngroups; i++)
  85                 for (j = 0; j < n; j++)
  86                         if (match_pattern(groups_byname[i], groups[j]))
  87                                 return 1;
  88         return 0;
  89 }
  90
  91 /*
  92  * Return 1 if one of user's groups matches group_pattern list.
  93  * Return 0 on negated or no match.
  94  */
  95 int
  96 ga_match_pattern_list(const char *group_pattern)
  97 {
  98         int i, found = 0;
  99         size_t len = strlen(group_pattern);
 100
 101         for (i = 0; i < ngroups; i++) {
 102                 switch (match_pattern_list(groups_byname[i],
 103                     group_pattern, len, 0)) {
 104                 case -1:
 105                         return 0;       /* Negated match wins */
 106                 case 0:
 107                         continue;
 108                 case 1:
 109                         found = 1;
 110                 }
 111         }
 112         return found;
 113 }
 114
 115 /*
 116  * Free memory allocated for group access list.
 117  */
 118 void
 119 ga_free(void)
 120 {
 121         int i;
 122
 123         if (ngroups > 0) {
 124                 for (i = 0; i < ngroups; i++)
 125                         xfree(groups_byname[i]);
 126                 ngroups = 0;
 127                 xfree(groups_byname);
 128         }
 129 }