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     { "get-keys",       KADM5_PRIV_GET_KEYS },
  48     { NULL,             0 }
  49 };
  50
  51 kadm5_ret_t
  52 _kadm5_string_to_privs(const char *s, uint32_t* privs)
  53 {
  54     int flags;
  55     flags = parse_flags(s, acl_units, 0);
  56     if(flags < 0)
  57         return KADM5_FAILURE;
  58     *privs = flags;
  59     return 0;
  60 }
  61
  62 kadm5_ret_t
  63 _kadm5_privs_to_string(uint32_t privs, char *string, size_t len)
  64 {
  65     if(privs == 0)
  66         strlcpy(string, "none", len);
  67     else
  68         unparse_flags(privs, acl_units + 1, string, len);
  69     return 0;
  70 }
  71
  72 /*
  73  * retrieve the right for the current caller on `princ' (NULL means all)
  74  * and store them in `ret_flags'
  75  * return 0 or an error.
  76  */
  77
  78 static kadm5_ret_t
  79 fetch_acl (kadm5_server_context *context,
  80            krb5_const_principal princ,
  81            unsigned *ret_flags)
  82 {
  83     FILE *f;
  84     krb5_error_code ret = 0;
  85     char buf[256];
  86
  87     *ret_flags = 0;
  88
  89     /* no acl file -> no rights */
  90     f = fopen(context->config.acl_file, "r");
  91     if (f == NULL)
  92         return 0;
  93
  94     while(fgets(buf, sizeof(buf), f) != NULL) {
  95         char *foo = NULL, *p;
  96         krb5_principal this_princ;
  97         unsigned flags = 0;
  98
  99         p = strtok_r(buf, " \t\n", &foo);
 100         if(p == NULL)
 101             continue;
 102         if (*p == '#')          /* comment */
 103             continue;
 104         ret = krb5_parse_name(context->context, p, &this_princ);
 105         if(ret)
 106             break;
 107         if(!krb5_principal_compare(context->context,
 108                                    context->caller, this_princ)) {
 109             krb5_free_principal(context->context, this_princ);
 110             continue;
 111         }
 112         krb5_free_principal(context->context, this_princ);
 113         p = strtok_r(NULL, " \t\n", &foo);
 114         if(p == NULL)
 115             continue;
 116         ret = _kadm5_string_to_privs(p, &flags);
 117         if (ret)
 118             break;
 119         p = strtok_r(NULL, " \t\n", &foo);
 120         if (p == NULL) {
 121             *ret_flags = flags;
 122             break;
 123         }
 124         if (princ != NULL) {
 125             krb5_principal pattern_princ;
 126             krb5_boolean match;
 127
 128             ret = krb5_parse_name (context->context, p, &pattern_princ);
 129             if (ret)
 130                 break;
 131             match = krb5_principal_match (context->context,
 132                                           princ, pattern_princ);
 133             krb5_free_principal (context->context, pattern_princ);
 134             if (match) {
 135                 *ret_flags = flags;
 136                 break;
 137             }
 138         }
 139     }
 140     fclose(f);
 141     return ret;
 142 }
 143
 144 /*
 145  * set global acl flags in `context' for the current caller.
 146  * return 0 on success or an error
 147  */
 148
 149 kadm5_ret_t
 150 _kadm5_acl_init(kadm5_server_context *context)
 151 {
 152     krb5_principal princ;
 153     krb5_error_code ret;
 154
 155     ret = krb5_parse_name(context->context, KADM5_ADMIN_SERVICE, &princ);
 156     if (ret)
 157         return ret;
 158     ret = krb5_principal_compare(context->context, context->caller, princ);
 159     krb5_free_principal(context->context, princ);
 160     if(ret != 0) {
 161         context->acl_flags = KADM5_PRIV_ALL;
 162         return 0;
 163     }
 164
 165     return fetch_acl (context, NULL, &context->acl_flags);
 166 }
 167
 168 /*
 169  * check if `flags' allows `op'
 170  * return 0 if OK or an error
 171  */
 172
 173 static kadm5_ret_t
 174 check_flags (unsigned op,
 175              unsigned flags)
 176 {
 177     unsigned res = ~flags & op;
 178
 179     if(res & KADM5_PRIV_GET)
 180         return KADM5_AUTH_GET;
 181     if(res & KADM5_PRIV_GET_KEYS)
 182         return KADM5_AUTH_GET_KEYS;
 183     if(res & KADM5_PRIV_ADD)
 184         return KADM5_AUTH_ADD;
 185     if(res & KADM5_PRIV_MODIFY)
 186         return KADM5_AUTH_MODIFY;
 187     if(res & KADM5_PRIV_DELETE)
 188         return KADM5_AUTH_DELETE;
 189     if(res & KADM5_PRIV_CPW)
 190         return KADM5_AUTH_CHANGEPW;
 191     if(res & KADM5_PRIV_LIST)
 192         return KADM5_AUTH_LIST;
 193     if(res)
 194         return KADM5_AUTH_INSUFFICIENT;
 195     return 0;
 196 }
 197
 198 /*
 199  * return 0 if the current caller in `context' is allowed to perform
 200  * `op' on `princ' and otherwise an error
 201  * princ == NULL if it's not relevant.
 202  */
 203
 204 kadm5_ret_t
 205 _kadm5_acl_check_permission(kadm5_server_context *context,
 206                             unsigned op,
 207                             krb5_const_principal princ)
 208 {
 209     kadm5_ret_t ret;
 210     unsigned princ_flags;
 211
 212     ret = check_flags (op, context->acl_flags);
 213     if (ret == 0)
 214         return ret;
 215     ret = fetch_acl (context, princ, &princ_flags);
 216     if (ret)
 217         return ret;
 218     return check_flags (op, princ_flags);
 219 }