groupaccess.c

   1 /* $OpenBSD: groupaccess.c,v 1.10 2006/07/17 01:31:09 stevesk 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
  30 #include <grp.h>
  31 #include <unistd.h>
  32
  33 #include "groupaccess.h"
  34 #include "xmalloc.h"
  35 #include "match.h"
  36 #include "log.h"
  37
  38 static int ngroups;
  39 static char **groups_byname;
  40
  41 /*
  42  * Initialize group access list for user with primary (base) and
  43  * supplementary groups.  Return the number of groups in the list.
  44  */
  45 int
  46 ga_init(const char *user, gid_t base)
  47 {
  48         gid_t *groups_bygid;
  49         int i, j;
  50         struct group *gr;
  51
  52         if (ngroups > 0)
  53                 ga_free();
  54
  55         ngroups = NGROUPS_MAX;
  56 #if defined(HAVE_SYSCONF) && defined(_SC_NGROUPS_MAX)
  57         ngroups = MAX(NGROUPS_MAX, sysconf(_SC_NGROUPS_MAX));
  58 #endif
  59
  60         groups_bygid = xcalloc(ngroups, sizeof(*groups_bygid));
  61         groups_byname = xcalloc(ngroups, sizeof(*groups_byname));
  62
  63         if (getgrouplist(user, base, groups_bygid, &ngroups) == -1)
  64                 logit("getgrouplist: groups list too small");
  65         for (i = 0, j = 0; i < ngroups; i++)
  66                 if ((gr = getgrgid(groups_bygid[i])) != NULL)
  67                         groups_byname[j++] = xstrdup(gr->gr_name);
  68         xfree(groups_bygid);
  69         return (ngroups = j);
  70 }
  71
  72 /*
  73  * Return 1 if one of user's groups is contained in groups.
  74  * Return 0 otherwise.  Use match_pattern() for string comparison.
  75  */
  76 int
  77 ga_match(char * const *groups, int n)
  78 {
  79         int i, j;
  80
  81         for (i = 0; i < ngroups; i++)
  82                 for (j = 0; j < n; j++)
  83                         if (match_pattern(groups_byname[i], groups[j]))
  84                                 return 1;
  85         return 0;
  86 }
  87
  88 /*
  89  * Free memory allocated for group access list.
  90  */
  91 void
  92 ga_free(void)
  93 {
  94         int i;
  95
  96         if (ngroups > 0) {
  97                 for (i = 0; i < ngroups; i++)
  98                         xfree(groups_byname[i]);
  99                 ngroups = 0;
 100                 xfree(groups_byname);
 101         }
 102 }