lib/kadm5/acl.c

   1 /*
   2  * Copyright (c) 1997 - 2001 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "kadm5_locl.h"
  35
  36 RCSID("$Id$");
  37
  38 static struct units acl_units[] = {
  39     { "all",            KADM5_PRIV_ALL },
  40     { "change-password",KADM5_PRIV_CPW },
  41     { "cpw",            KADM5_PRIV_CPW },
  42     { "list",           KADM5_PRIV_LIST },
  43     { "delete",         KADM5_PRIV_DELETE },
  44     { "modify",         KADM5_PRIV_MODIFY },
  45     { "add",            KADM5_PRIV_ADD },
  46     { "get",            KADM5_PRIV_GET },
  47     { NULL }
  48 };
  49
  50 kadm5_ret_t
  51 _kadm5_string_to_privs(const char *s, uint32_t* privs)
  52 {
  53     int flags;
  54     flags = parse_flags(s, acl_units, 0);
  55     if(flags < 0)
  56         return KADM5_FAILURE;
  57     *privs = flags;
  58     return 0;
  59 }
  60
  61 kadm5_ret_t
  62 _kadm5_privs_to_string(uint32_t privs, char *string, size_t len)
  63 {
  64     if(privs == 0)
  65         strlcpy(string, "none", len);
  66     else
  67         unparse_flags(privs, acl_units + 1, string, len);
  68     return 0;
  69 }
  70
  71 /*
  72  * retrieve the right for the current caller on `princ' (NULL means all)
  73  * and store them in `ret_flags'
  74  * return 0 or an error.
  75  */
  76
  77 static kadm5_ret_t
  78 fetch_acl (kadm5_server_context *context,
  79            krb5_const_principal princ,
  80            unsigned *ret_flags)
  81 {
  82     FILE *f;
  83     krb5_error_code ret = 0;
  84     char buf[256];
  85
  86     *ret_flags = 0;
  87
  88     /* no acl file -> no rights */
  89     f = fopen(context->config.acl_file, "r");
  90     if (f == NULL)
  91         return 0;
  92
  93     while(fgets(buf, sizeof(buf), f) != NULL) {
  94         char *foo = NULL, *p;
  95         krb5_principal this_princ;
  96         unsigned flags = 0;
  97
  98         p = strtok_r(buf, " \t\n", &foo);
  99         if(p == NULL)
 100             continue;
 101         if (*p == '#')          /* comment */
 102             continue;
 103         ret = krb5_parse_name(context->context, p, &this_princ);
 104         if(ret)
 105             break;
 106         if(!krb5_principal_compare(context->context,
 107                                    context->caller, this_princ)) {
 108             krb5_free_principal(context->context, this_princ);
 109             continue;
 110         }
 111         krb5_free_principal(context->context, this_princ);
 112         p = strtok_r(NULL, " \t\n", &foo);
 113         if(p == NULL)
 114             continue;
 115         ret = _kadm5_string_to_privs(p, &flags);
 116         if (ret)
 117             break;
 118         p = strtok_r(NULL, " \t\n", &foo);
 119         if (p == NULL) {
 120             *ret_flags = flags;
 121             break;
 122         }
 123         if (princ != NULL) {
 124             krb5_principal pattern_princ;
 125             krb5_boolean match;
 126
 127             ret = krb5_parse_name (context->context, p, &pattern_princ);
 128             if (ret)
 129                 break;
 130             match = krb5_principal_match (context->context,
 131                                           princ, pattern_princ);
 132             krb5_free_principal (context->context, pattern_princ);
 133             if (match) {
 134                 *ret_flags = flags;
 135                 break;
 136             }
 137         }
 138     }
 139     fclose(f);
 140     return ret;
 141 }
 142
 143 /*
 144  * set global acl flags in `context' for the current caller.
 145  * return 0 on success or an error
 146  */
 147
 148 kadm5_ret_t
 149 _kadm5_acl_init(kadm5_server_context *context)
 150 {
 151     krb5_principal princ;
 152     krb5_error_code ret;
 153
 154     ret = krb5_parse_name(context->context, KADM5_ADMIN_SERVICE, &princ);
 155     if (ret)
 156         return ret;
 157     ret = krb5_principal_compare(context->context, context->caller, princ);
 158     krb5_free_principal(context->context, princ);
 159     if(ret != 0) {
 160         context->acl_flags = KADM5_PRIV_ALL;
 161         return 0;
 162     }
 163
 164     return fetch_acl (context, NULL, &context->acl_flags);
 165 }
 166
 167 /*
 168  * check if `flags' allows `op'
 169  * return 0 if OK or an error
 170  */
 171
 172 static kadm5_ret_t
 173 check_flags (unsigned op,
 174              unsigned flags)
 175 {
 176     unsigned res = ~flags & op;
 177
 178     if(res & KADM5_PRIV_GET)
 179         return KADM5_AUTH_GET;
 180     if(res & KADM5_PRIV_ADD)
 181         return KADM5_AUTH_ADD;
 182     if(res & KADM5_PRIV_MODIFY)
 183         return KADM5_AUTH_MODIFY;
 184     if(res & KADM5_PRIV_DELETE)
 185         return KADM5_AUTH_DELETE;
 186     if(res & KADM5_PRIV_CPW)
 187         return KADM5_AUTH_CHANGEPW;
 188     if(res & KADM5_PRIV_LIST)
 189         return KADM5_AUTH_LIST;
 190     if(res)
 191         return KADM5_AUTH_INSUFFICIENT;
 192     return 0;
 193 }
 194
 195 /*
 196  * return 0 if the current caller in `context' is allowed to perform
 197  * `op' on `princ' and otherwise an error
 198  * princ == NULL if it's not relevant.
 199  */
 200
 201 kadm5_ret_t
 202 _kadm5_acl_check_permission(kadm5_server_context *context,
 203                             unsigned op,
 204                             krb5_const_principal princ)
 205 {
 206     kadm5_ret_t ret;
 207     unsigned princ_flags;
 208
 209     ret = check_flags (op, context->acl_flags);
 210     if (ret == 0)
 211         return ret;
 212     ret = fetch_acl (context, princ, &princ_flags);
 213     if (ret)
 214         return ret;
 215     return check_flags (op, princ_flags);
 216 }