kcm/acl.c

   1 /*
   2  * Copyright (c) 2005, PADL Software Pty Ltd.
   3  * 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  *
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  *
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * 3. Neither the name of PADL Software nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY PADL SOFTWARE AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL PADL SOFTWARE OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #include "kcm_locl.h"
  34
  35 RCSID("$Id$");
  36
  37 krb5_error_code
  38 kcm_access(krb5_context context,
  39            kcm_client *client,
  40            kcm_operation opcode,
  41            kcm_ccache ccache)
  42 {
  43     int read_p = 0;
  44     int write_p = 0;
  45     uint16_t mask;
  46     krb5_error_code ret;
  47
  48     KCM_ASSERT_VALID(ccache);
  49
  50     switch (opcode) {
  51     case KCM_OP_INITIALIZE:
  52     case KCM_OP_DESTROY:
  53     case KCM_OP_STORE:
  54     case KCM_OP_REMOVE_CRED:
  55     case KCM_OP_SET_FLAGS:
  56     case KCM_OP_CHOWN:
  57     case KCM_OP_CHMOD:
  58     case KCM_OP_GET_INITIAL_TICKET:
  59     case KCM_OP_GET_TICKET:
  60     case KCM_OP_MOVE_CACHE:
  61         write_p = 1;
  62         read_p = 0;
  63         break;
  64     case KCM_OP_NOOP:
  65     case KCM_OP_GET_NAME:
  66     case KCM_OP_RESOLVE:
  67     case KCM_OP_GEN_NEW:
  68     case KCM_OP_RETRIEVE:
  69     case KCM_OP_GET_PRINCIPAL:
  70     case KCM_OP_GET_FIRST:
  71     case KCM_OP_GET_NEXT:
  72     case KCM_OP_END_GET:
  73     case KCM_OP_MAX:
  74         write_p = 0;
  75         read_p = 1;
  76         break;
  77     }
  78
  79     if (ccache->flags & KCM_FLAGS_OWNER_IS_SYSTEM) {
  80         /* System caches cannot be reinitialized or destroyed by users */
  81         if (opcode == KCM_OP_INITIALIZE ||
  82             opcode == KCM_OP_DESTROY ||
  83             opcode == KCM_OP_REMOVE_CRED ||
  84             opcode == KCM_OP_MOVE_CACHE) {
  85             ret = KRB5_FCC_PERM;
  86             goto out;
  87         }
  88
  89         /* Let root always read system caches */
  90         if (client->uid == 0) {
  91             ret = 0;
  92             goto out;
  93         }
  94     }
  95
  96     mask = 0;
  97
  98     /* Root may do whatever they like */
  99     if (client->uid == ccache->uid || CLIENT_IS_ROOT(client)) {
 100         if (read_p)
 101             mask |= S_IRUSR;
 102         if (write_p)
 103             mask |= S_IWUSR;
 104     } else if (client->gid == ccache->gid || CLIENT_IS_ROOT(client)) {
 105         if (read_p)
 106             mask |= S_IRGRP;
 107         if (write_p)
 108             mask |= S_IWGRP;
 109     } else {
 110         if (read_p)
 111             mask |= S_IROTH;
 112         if (write_p)
 113             mask |= S_IWOTH;
 114     }
 115
 116     ret = ((ccache->mode & mask) == mask) ? 0 : KRB5_FCC_PERM;
 117
 118 out:
 119     if (ret) {
 120         kcm_log(2, "Process %d is not permitted to call %s on cache %s",
 121                 client->pid, kcm_op2string(opcode), ccache->name);
 122     }
 123
 124     return ret;
 125 }
 126
 127 krb5_error_code
 128 kcm_chmod(krb5_context context,
 129           kcm_client *client,
 130           kcm_ccache ccache,
 131           uint16_t mode)
 132 {
 133     KCM_ASSERT_VALID(ccache);
 134
 135     /* System cache mode can only be set at startup */
 136     if (ccache->flags & KCM_FLAGS_OWNER_IS_SYSTEM)
 137         return KRB5_FCC_PERM;
 138
 139     if (ccache->uid != client->uid)
 140         return KRB5_FCC_PERM;
 141
 142     if (ccache->gid != client->gid)
 143         return KRB5_FCC_PERM;
 144
 145     HEIMDAL_MUTEX_lock(&ccache->mutex);
 146
 147     ccache->mode = mode;
 148
 149     HEIMDAL_MUTEX_unlock(&ccache->mutex);
 150
 151     return 0;
 152 }
 153
 154 krb5_error_code
 155 kcm_chown(krb5_context context,
 156           kcm_client *client,
 157           kcm_ccache ccache,
 158           uid_t uid,
 159           gid_t gid)
 160 {
 161     KCM_ASSERT_VALID(ccache);
 162
 163     /* System cache owner can only be set at startup */
 164     if (ccache->flags & KCM_FLAGS_OWNER_IS_SYSTEM)
 165         return KRB5_FCC_PERM;
 166
 167     if (ccache->uid != client->uid)
 168         return KRB5_FCC_PERM;
 169
 170     if (ccache->gid != client->gid)
 171         return KRB5_FCC_PERM;
 172
 173     HEIMDAL_MUTEX_lock(&ccache->mutex);
 174
 175     ccache->uid = uid;
 176     ccache->gid = gid;
 177
 178     HEIMDAL_MUTEX_unlock(&ccache->mutex);
 179
 180     return 0;
 181 }
 182