groupaccess.c

   1 /* $OpenBSD: groupaccess.c,v 1.12 2006/08/03 03:34:42 deraadt 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
  35 #include "xmalloc.h"
  36 #include "groupaccess.h"
  37 #include "match.h"
  38 #include "log.h"
  39
  40 static int ngroups;
  41 static char **groups_byname;
  42
  43 /*
  44  * Initialize group access list for user with primary (base) and
  45  * supplementary groups.  Return the number of groups in the list.
  46  */
  47 int
  48 ga_init(const char *user, gid_t base)
  49 {
  50         gid_t *groups_bygid;
  51         int i, j;
  52         struct group *gr;
  53
  54         if (ngroups > 0)
  55                 ga_free();
  56
  57         ngroups = NGROUPS_MAX;
  58 #if defined(HAVE_SYSCONF) && defined(_SC_NGROUPS_MAX)
  59         ngroups = MAX(NGROUPS_MAX, sysconf(_SC_NGROUPS_MAX));
  60 #endif
  61
  62         groups_bygid = xcalloc(ngroups, sizeof(*groups_bygid));
  63         groups_byname = xcalloc(ngroups, sizeof(*groups_byname));
  64
  65         if (getgrouplist(user, base, groups_bygid, &ngroups) == -1)
  66                 logit("getgrouplist: groups list too small");
  67         for (i = 0, j = 0; i < ngroups; i++)
  68                 if ((gr = getgrgid(groups_bygid[i])) != NULL)
  69                         groups_byname[j++] = xstrdup(gr->gr_name);
  70         xfree(groups_bygid);
  71         return (ngroups = j);
  72 }
  73
  74 /*
  75  * Return 1 if one of user's groups is contained in groups.
  76  * Return 0 otherwise.  Use match_pattern() for string comparison.
  77  */
  78 int
  79 ga_match(char * const *groups, int n)
  80 {
  81         int i, j;
  82
  83         for (i = 0; i < ngroups; i++)
  84                 for (j = 0; j < n; j++)
  85                         if (match_pattern(groups_byname[i], groups[j]))
  86                                 return 1;
  87         return 0;
  88 }
  89
  90 /*
  91  * Free memory allocated for group access list.
  92  */
  93 void
  94 ga_free(void)
  95 {
  96         int i;
  97
  98         if (ngroups > 0) {
  99                 for (i = 0; i < ngroups; i++)
 100                         xfree(groups_byname[i]);
 101                 ngroups = 0;
 102                 xfree(groups_byname);
 103         }
 104 }