util/acl.c

   1 /*
   2  * QEMU access control list management
   3  *
   4  * Copyright (C) 2009 Red Hat, Inc
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24
  25
  26 #include "qemu-common.h"
  27 #include "qemu/acl.h"
  28
  29 #ifdef CONFIG_FNMATCH
  30 #include <fnmatch.h>
  31 #endif
  32
  33
  34 static unsigned int nacls = 0;
  35 static qemu_acl **acls = NULL;
  36
  37
  38
  39 qemu_acl *qemu_acl_find(const char *aclname)
  40 {
  41     int i;
  42     for (i = 0 ; i < nacls ; i++) {
  43         if (strcmp(acls[i]->aclname, aclname) == 0)
  44             return acls[i];
  45     }
  46
  47     return NULL;
  48 }
  49
  50 qemu_acl *qemu_acl_init(const char *aclname)
  51 {
  52     qemu_acl *acl;
  53
  54     acl = qemu_acl_find(aclname);
  55     if (acl)
  56         return acl;
  57
  58     acl = g_malloc(sizeof(*acl));
  59     acl->aclname = g_strdup(aclname);
  60     /* Deny by default, so there is no window of "open
  61      * access" between QEMU starting, and the user setting
  62      * up ACLs in the monitor */
  63     acl->defaultDeny = 1;
  64
  65     acl->nentries = 0;
  66     QTAILQ_INIT(&acl->entries);
  67
  68     acls = g_realloc(acls, sizeof(*acls) * (nacls +1));
  69     acls[nacls] = acl;
  70     nacls++;
  71
  72     return acl;
  73 }
  74
  75 int qemu_acl_party_is_allowed(qemu_acl *acl,
  76                               const char *party)
  77 {
  78     qemu_acl_entry *entry;
  79
  80     QTAILQ_FOREACH(entry, &acl->entries, next) {
  81 #ifdef CONFIG_FNMATCH
  82         if (fnmatch(entry->match, party, 0) == 0)
  83             return entry->deny ? 0 : 1;
  84 #else
  85         /* No fnmatch, so fallback to exact string matching
  86          * instead of allowing wildcards */
  87         if (strcmp(entry->match, party) == 0)
  88             return entry->deny ? 0 : 1;
  89 #endif
  90     }
  91
  92     return acl->defaultDeny ? 0 : 1;
  93 }
  94
  95
  96 void qemu_acl_reset(qemu_acl *acl)
  97 {
  98     qemu_acl_entry *entry, *next_entry;
  99
 100     /* Put back to deny by default, so there is no window
 101      * of "open access" while the user re-initializes the
 102      * access control list */
 103     acl->defaultDeny = 1;
 104     QTAILQ_FOREACH_SAFE(entry, &acl->entries, next, next_entry) {
 105         QTAILQ_REMOVE(&acl->entries, entry, next);
 106         g_free(entry->match);
 107         g_free(entry);
 108     }
 109     acl->nentries = 0;
 110 }
 111
 112
 113 int qemu_acl_append(qemu_acl *acl,
 114                     int deny,
 115                     const char *match)
 116 {
 117     qemu_acl_entry *entry;
 118
 119     entry = g_malloc(sizeof(*entry));
 120     entry->match = g_strdup(match);
 121     entry->deny = deny;
 122
 123     QTAILQ_INSERT_TAIL(&acl->entries, entry, next);
 124     acl->nentries++;
 125
 126     return acl->nentries;
 127 }
 128
 129
 130 int qemu_acl_insert(qemu_acl *acl,
 131                     int deny,
 132                     const char *match,
 133                     int index)
 134 {
 135     qemu_acl_entry *entry;
 136     qemu_acl_entry *tmp;
 137     int i = 0;
 138
 139     if (index <= 0)
 140         return -1;
 141     if (index > acl->nentries) {
 142         return qemu_acl_append(acl, deny, match);
 143     }
 144
 145     entry = g_malloc(sizeof(*entry));
 146     entry->match = g_strdup(match);
 147     entry->deny = deny;
 148
 149     QTAILQ_FOREACH(tmp, &acl->entries, next) {
 150         i++;
 151         if (i == index) {
 152             QTAILQ_INSERT_BEFORE(tmp, entry, next);
 153             acl->nentries++;
 154             break;
 155         }
 156     }
 157
 158     return i;
 159 }
 160
 161 int qemu_acl_remove(qemu_acl *acl,
 162                     const char *match)
 163 {
 164     qemu_acl_entry *entry;
 165     int i = 0;
 166
 167     QTAILQ_FOREACH(entry, &acl->entries, next) {
 168         i++;
 169         if (strcmp(entry->match, match) == 0) {
 170             QTAILQ_REMOVE(&acl->entries, entry, next);
 171             acl->nentries--;
 172             g_free(entry->match);
 173             g_free(entry);
 174             return i;
 175         }
 176     }
 177     return -1;
 178 }
 179
 180
 181 /*
 182  * Local variables:
 183  *  c-indent-level: 4
 184  *  c-basic-offset: 4
 185  *  tab-width: 8
 186  * End:
 187  */