crypto/openssh/groupaccess.c

   1 /* $OpenBSD: groupaccess.c,v 1.17 2019/03/06 22:14:23 dtucker 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 #include <stdarg.h>
  33 #include <stdlib.h>
  34 #include <string.h>
  35 #include <limits.h>
  36
  37 #include "xmalloc.h"
  38 #include "groupaccess.h"
  39 #include "match.h"
  40 #include "log.h"
  41
  42 static int ngroups;
  43 static char **groups_byname;
  44
  45 /*
  46  * Initialize group access list for user with primary (base) and
  47  * supplementary groups.  Return the number of groups in the list.
  48  */
  49 int
  50 ga_init(const char *user, gid_t base)
  51 {
  52         gid_t *groups_bygid;
  53         int i, j, retry = 0;
  54         struct group *gr;
  55
  56         if (ngroups > 0)
  57                 ga_free();
  58
  59         ngroups = NGROUPS_MAX;
  60 #if defined(HAVE_SYSCONF) && defined(_SC_NGROUPS_MAX)
  61         ngroups = MAX(NGROUPS_MAX, sysconf(_SC_NGROUPS_MAX));
  62 #endif
  63
  64         groups_bygid = xcalloc(ngroups, sizeof(*groups_bygid));
  65         while (getgrouplist(user, base, groups_bygid, &ngroups) == -1) {
  66                 if (retry++ > 0)
  67                         fatal("getgrouplist: groups list too small");
  68                 groups_bygid = xreallocarray(groups_bygid, ngroups,
  69                     sizeof(*groups_bygid));
  70         }
  71         groups_byname = xcalloc(ngroups, sizeof(*groups_byname));
  72
  73         for (i = 0, j = 0; i < ngroups; i++)
  74                 if ((gr = getgrgid(groups_bygid[i])) != NULL)
  75                         groups_byname[j++] = xstrdup(gr->gr_name);
  76         free(groups_bygid);
  77         return (ngroups = j);
  78 }
  79
  80 /*
  81  * Return 1 if one of user's groups is contained in groups.
  82  * Return 0 otherwise.  Use match_pattern() for string comparison.
  83  */
  84 int
  85 ga_match(char * const *groups, int n)
  86 {
  87         int i, j;
  88
  89         for (i = 0; i < ngroups; i++)
  90                 for (j = 0; j < n; j++)
  91                         if (match_pattern(groups_byname[i], groups[j]))
  92                                 return 1;
  93         return 0;
  94 }
  95
  96 /*
  97  * Return 1 if one of user's groups matches group_pattern list.
  98  * Return 0 on negated or no match.
  99  */
 100 int
 101 ga_match_pattern_list(const char *group_pattern)
 102 {
 103         int i, found = 0;
 104
 105         for (i = 0; i < ngroups; i++) {
 106                 switch (match_usergroup_pattern_list(groups_byname[i],
 107                     group_pattern)) {
 108                 case -1:
 109                         return 0;       /* Negated match wins */
 110                 case 0:
 111                         continue;
 112                 case 1:
 113                         found = 1;
 114                 }
 115         }
 116         return found;
 117 }
 118
 119 /*
 120  * Free memory allocated for group access list.
 121  */
 122 void
 123 ga_free(void)
 124 {
 125         int i;
 126
 127         if (ngroups > 0) {
 128                 for (i = 0; i < ngroups; i++)
 129                         free(groups_byname[i]);
 130                 ngroups = 0;
 131                 free(groups_byname);
 132                 groups_byname = NULL;
 133         }
 134 }