authz: add QAuthZList object type for an access control list

Add a QAuthZList object type that implements the QAuthZ interface. This
built-in implementation maintains a trivial access control list with a
sequence of match rules and a final default policy. This replicates the
functionality currently provided by the qemu_acl module.

To create an instance of this object via the QMP monitor, the syntax
used would be:

  {
    "execute": "object-add",
    "arguments": {
      "qom-type": "authz-list",
      "id": "authz0",
      "props": {
        "rules": [
           { "match": "fred", "policy": "allow", "format": "exact" },
           { "match": "bob", "policy": "allow", "format": "exact" },
           { "match": "danb", "policy": "deny", "format": "glob" },
           { "match": "dan*", "policy": "allow", "format": "exact" },
        ],
        "policy": "deny"
      }
    }
  }

This sets up an authorization rule that allows 'fred', 'bob' and anyone
whose name starts with 'dan', except for 'danb'. Everyone unmatched is
denied.

It is not currently possible to create this via -object, since there is
no syntax supported to specify non-scalar properties for objects. This
is likely to be addressed by later support for using JSON with -object,
or an equivalent approach.

In any case the future "authz-listfile" object can be used from the
CLI and is likely a better choice, as it allows the ACL to be refreshed
automatically on change.

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

3 files changed, 60 insertions, 1 deletions

diff --git a/qapi/Makefile.objs b/qapi/Makefile.objs
index 87e4df1..77acca0 100644
--- a/qapi/Makefile.objs
+++ b/qapi/Makefile.objs
@@ -5,7 +5,7 @@ util-obj-y += opts-visitor.o qapi-clone-visitor.o
 util-obj-y += qmp-event.o
 util-obj-y += qapi-util.o
 
-QAPI_COMMON_MODULES = block-core block char common crypto introspect
+QAPI_COMMON_MODULES = authz block-core block char common crypto introspect
 QAPI_COMMON_MODULES += job migration misc net rdma rocker run-state
 QAPI_COMMON_MODULES += sockets tpm trace transaction ui
 QAPI_TARGET_MODULES = target
diff --git a/qapi/authz.json b/qapi/authz.json
new file mode 100644
index 0000000..1c836a3
--- /dev/null
+++ b/qapi/authz.json
@@ -0,0 +1,58 @@
+# -*- Mode: Python -*-
+#
+# QAPI authz definitions
+
+##
+# @QAuthZListPolicy:
+#
+# The authorization policy result
+#
+# @deny: deny access
+# @allow: allow access
+#
+# Since: 4.0
+##
+{ 'enum': 'QAuthZListPolicy',
+  'prefix': 'QAUTHZ_LIST_POLICY',
+  'data': ['deny', 'allow']}
+
+##
+# @QAuthZListFormat:
+#
+# The authorization policy match format
+#
+# @exact: an exact string match
+# @glob: string with ? and * shell wildcard support
+#
+# Since: 4.0
+##
+{ 'enum': 'QAuthZListFormat',
+  'prefix': 'QAUTHZ_LIST_FORMAT',
+  'data': ['exact', 'glob']}
+
+##
+# @QAuthZListRule:
+#
+# A single authorization rule.
+#
+# @match: a string or glob to match against a user identity
+# @policy: the result to return if @match evaluates to true
+# @format: the format of the @match rule (default 'exact')
+#
+# Since: 4.0
+##
+{ 'struct': 'QAuthZListRule',
+  'data': {'match': 'str',
+           'policy': 'QAuthZListPolicy',
+           '*format': 'QAuthZListFormat'}}
+
+##
+# @QAuthZListRuleListHack:
+#
+# Not exposed via QMP; hack to generate QAuthZListRuleList
+# for use internally by the code.
+#
+# Since: 4.0
+##
+{ 'struct': 'QAuthZListRuleListHack',
+  'data': { 'unused': ['QAuthZListRule'] } }
diff --git a/qapi/qapi-schema.json b/qapi/qapi-schema.json
index db61bfd..a34899c 100644
--- a/qapi/qapi-schema.json
+++ b/qapi/qapi-schema.json
@@ -92,6 +92,7 @@
 { 'include': 'rocker.json' }
 { 'include': 'tpm.json' }
 { 'include': 'ui.json' }
+{ 'include': 'authz.json' }
 { 'include': 'migration.json' }
 { 'include': 'transaction.json' }
 { 'include': 'trace.json' }