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authoraliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>2009-03-06 20:27:37 +0000
committeraliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>2009-03-06 20:27:37 +0000
commit76655d6dece88bd00e190956e8e4285b682edcbb (patch)
tree12e9365035a18d6a0bbfdfef0362999c9752a434 /acl.c
parent1263b7d6131cdaed2c460cf03757aaaf5696ec47 (diff)
Support ACLs for controlling VNC access ("Daniel P. Berrange")
This patch introduces a generic internal API for access control lists to be used by network servers in QEMU. It adds support for checking these ACL in the VNC server, in two places. The first ACL is for the SASL authentication mechanism, checking the SASL username. This ACL is called 'vnc.username'. The second is for the TLS authentication mechanism, when x509 client certificates are turned on, checking against the Distinguished Name of the client. This ACL is called 'vnc.x509dname' The internal API provides for an ACL with the following characteristics - A unique name, eg vnc.username, and vnc.x509dname. - A default policy, allow or deny - An ordered series of match rules, with allow or deny policy If none of the match rules apply, then the default policy is used. There is a monitor API to manipulate the ACLs, which I'll describe via examples (qemu) acl show vnc.username policy: allow (qemu) acl policy vnc.username denya acl: policy set to 'deny' (qemu) acl allow vnc.username fred acl: added rule at position 1 (qemu) acl allow vnc.username bob acl: added rule at position 2 (qemu) acl allow vnc.username joe 1 acl: added rule at position 1 (qemu) acl show vnc.username policy: deny 0: allow fred 1: allow joe 2: allow bob (qemu) acl show vnc.x509dname policy: allow (qemu) acl policy vnc.x509dname deny acl: policy set to 'deny' (qemu) acl allow vnc.x509dname C=GB,O=ACME,L=London,CN=* acl: added rule at position 1 (qemu) acl allow vnc.x509dname C=GB,O=ACME,L=Boston,CN=bob acl: added rule at position 2 (qemu) acl show vnc.x509dname policy: deny 0: allow C=GB,O=ACME,L=London,CN=* 1: allow C=GB,O=ACME,L=Boston,CN=bob By default the VNC server will not use any ACLs, allowing access to the server if the user successfully authenticates. To enable use of ACLs to restrict user access, the ',acl' flag should be given when starting QEMU. The initial ACL activated will be a 'deny all' policy and should be customized using monitor commands. eg enable SASL auth and ACLs qemu .... -vnc localhost:1,sasl,acl The next patch will provide a way to load a pre-defined ACL when starting up Makefile | 6 + b/acl.c | 185 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ b/acl.h | 74 ++++++++++++++++++++++ configure | 18 +++++ monitor.c | 95 ++++++++++++++++++++++++++++ qemu-doc.texi | 49 ++++++++++++++ vnc-auth-sasl.c | 16 +++- vnc-auth-sasl.h | 7 ++ vnc-tls.c | 19 +++++ vnc-tls.h | 3 vnc.c | 21 ++++++ vnc.h | 3 12 files changed, 491 insertions(+), 5 deletions(-) Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6726 c046a42c-6fe2-441c-8c8c-71466251a162
Diffstat (limited to 'acl.c')
-rw-r--r--acl.c185
1 files changed, 185 insertions, 0 deletions
diff --git a/acl.c b/acl.c
new file mode 100644
index 000000000..173bf95b0
--- /dev/null
+++ b/acl.c
@@ -0,0 +1,185 @@
+/*
+ * QEMU access control list management
+ *
+ * Copyright (C) 2009 Red Hat, Inc
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+
+#include "qemu-common.h"
+#include "sysemu.h"
+#include "acl.h"
+
+#ifdef HAVE_FNMATCH_H
+#include <fnmatch.h>
+#endif
+
+
+static unsigned int nacls = 0;
+static qemu_acl **acls = NULL;
+
+
+
+qemu_acl *qemu_acl_find(const char *aclname)
+{
+ int i;
+ for (i = 0 ; i < nacls ; i++) {
+ if (strcmp(acls[i]->aclname, aclname) == 0)
+ return acls[i];
+ }
+
+ return NULL;
+}
+
+qemu_acl *qemu_acl_init(const char *aclname)
+{
+ qemu_acl *acl;
+
+ acl = qemu_acl_find(aclname);
+ if (acl)
+ return acl;
+
+ acl = qemu_malloc(sizeof(*acl));
+ acl->aclname = qemu_strdup(aclname);
+ /* Deny by default, so there is no window of "open
+ * access" between QEMU starting, and the user setting
+ * up ACLs in the monitor */
+ acl->defaultDeny = 1;
+
+ acl->nentries = 0;
+ TAILQ_INIT(&acl->entries);
+
+ acls = qemu_realloc(acls, sizeof(*acls) * (nacls +1));
+ acls[nacls] = acl;
+ nacls++;
+
+ return acl;
+}
+
+int qemu_acl_party_is_allowed(qemu_acl *acl,
+ const char *party)
+{
+ qemu_acl_entry *entry;
+
+ TAILQ_FOREACH(entry, &acl->entries, next) {
+#ifdef HAVE_FNMATCH_H
+ if (fnmatch(entry->match, party, 0) == 0)
+ return entry->deny ? 0 : 1;
+#else
+ /* No fnmatch, so fallback to exact string matching
+ * instead of allowing wildcards */
+ if (strcmp(entry->match, party) == 0)
+ return entry->deny ? 0 : 1;
+#endif
+ }
+
+ return acl->defaultDeny ? 0 : 1;
+}
+
+
+void qemu_acl_reset(qemu_acl *acl)
+{
+ qemu_acl_entry *entry;
+
+ /* Put back to deny by default, so there is no window
+ * of "open access" while the user re-initializes the
+ * access control list */
+ acl->defaultDeny = 1;
+ TAILQ_FOREACH(entry, &acl->entries, next) {
+ TAILQ_REMOVE(&acl->entries, entry, next);
+ free(entry->match);
+ free(entry);
+ }
+ acl->nentries = 0;
+}
+
+
+int qemu_acl_append(qemu_acl *acl,
+ int deny,
+ const char *match)
+{
+ qemu_acl_entry *entry;
+
+ entry = qemu_malloc(sizeof(*entry));
+ entry->match = qemu_strdup(match);
+ entry->deny = deny;
+
+ TAILQ_INSERT_TAIL(&acl->entries, entry, next);
+ acl->nentries++;
+
+ return acl->nentries;
+}
+
+
+int qemu_acl_insert(qemu_acl *acl,
+ int deny,
+ const char *match,
+ int index)
+{
+ qemu_acl_entry *entry;
+ qemu_acl_entry *tmp;
+ int i = 0;
+
+ if (index <= 0)
+ return -1;
+ if (index >= acl->nentries)
+ return qemu_acl_append(acl, deny, match);
+
+
+ entry = qemu_malloc(sizeof(*entry));
+ entry->match = qemu_strdup(match);
+ entry->deny = deny;
+
+ TAILQ_FOREACH(tmp, &acl->entries, next) {
+ i++;
+ if (i == index) {
+ TAILQ_INSERT_BEFORE(tmp, entry, next);
+ acl->nentries++;
+ break;
+ }
+ }
+
+ return i;
+}
+
+int qemu_acl_remove(qemu_acl *acl,
+ const char *match)
+{
+ qemu_acl_entry *entry;
+ int i = 0;
+
+ TAILQ_FOREACH(entry, &acl->entries, next) {
+ i++;
+ if (strcmp(entry->match, match) == 0) {
+ TAILQ_REMOVE(&acl->entries, entry, next);
+ return i;
+ }
+ }
+ return -1;
+}
+
+
+/*
+ * Local variables:
+ * c-indent-level: 4
+ * c-basic-offset: 4
+ * tab-width: 8
+ * End:
+ */