[Qemu-devel] [PATCH 08/10] qapi: add strict mode to input visitor

[Paolo Bonzini <pbonzini@redhat.com>]

While QMP in general is designed so that it is possible to ignore
unknown arguments, in the case of the QMP server it is better to
reject them to detect bad clients.  In fact, we're already doing
this at the top level in the argument checker.  To extend this to
complex structures, add a mode to the input visitor where it checks
for unvisited keys and raises an error if it finds one.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 qapi/qmp-input-visitor.c |   48 +++++++++-
 qapi/qmp-input-visitor.h |    2 +
 test-qmp-input-strict.c  |  234 ++++++++++++++++++++++++++++++++++++++++++++++
 tests/Makefile           |    5 +-
 4 files changed, 285 insertions(+), 4 deletions(-)
 create mode 100644 test-qmp-input-strict.c

diff --git a/qapi/qmp-input-visitor.c b/qapi/qmp-input-visitor.c
index 97a0186..eb09874 100644
--- a/qapi/qmp-input-visitor.c
+++ b/qapi/qmp-input-visitor.c
@@ -24,6 +24,7 @@ typedef struct StackObject
 {
     QObject *obj;
     const QListEntry *entry;
+    GHashTable *h;
 } StackObject;
 
 struct QmpInputVisitor
@@ -31,6 +32,7 @@ struct QmpInputVisitor
     Visitor visitor;
     StackObject stack[QIV_STACK_SIZE];
     int nb_stack;
+    bool strict;
 };
 
 static QmpInputVisitor *to_qiv(Visitor *v)
@@ -45,6 +47,9 @@ static QObject *qmp_input_get_object(QmpInputVisitor *qiv,
 
     if (qobj) {
         if (name && qobject_type(qobj) == QTYPE_QDICT) {
+            if (qiv->stack[qiv->nb_stack - 1].h) {
+                g_hash_table_remove(qiv->stack[qiv->nb_stack - 1].h, name);
+            }
             return qdict_get(qobject_to_qdict(qobj), name);
         } else if (qiv->stack[qiv->nb_stack - 1].entry) {
             return qlist_entry_obj(qiv->stack[qiv->nb_stack - 1].entry);
@@ -54,20 +59,47 @@ static QObject *qmp_input_get_object(QmpInputVisitor *qiv,
     return qobj;
 }
 
+static void qdict_add_key(const char *key, QObject *obj, void *opaque)
+{
+    GHashTable *h = opaque;
+    g_hash_table_insert(h, (gpointer) key, NULL);
+}
+
 static void qmp_input_push(QmpInputVisitor *qiv, QObject *obj, Error **errp)
 {
-    qiv->stack[qiv->nb_stack].obj = obj;
-    qiv->stack[qiv->nb_stack].entry = NULL;
-    qiv->nb_stack++;
+    GHashTable *h;
 
     if (qiv->nb_stack >= QIV_STACK_SIZE) {
         error_set(errp, QERR_BUFFER_OVERRUN);
         return;
     }
+
+    qiv->stack[qiv->nb_stack].obj = obj;
+    qiv->stack[qiv->nb_stack].entry = NULL;
+    qiv->stack[qiv->nb_stack].h = NULL;
+
+    if (qiv->strict && qobject_type(obj) == QTYPE_QDICT) {
+        h = g_hash_table_new(g_str_hash, g_str_equal);
+        qdict_iter(qobject_to_qdict(obj), qdict_add_key, h);
+        qiv->stack[qiv->nb_stack].h = h;
+    }
+
+    qiv->nb_stack++;
 }
 
 static void qmp_input_pop(QmpInputVisitor *qiv, Error **errp)
 {
+    GHashTableIter iter;
+    gpointer key;
+
+    if (qiv->strict && qiv->stack[qiv->nb_stack - 1].h) {
+        g_hash_table_iter_init(&iter, qiv->stack[qiv->nb_stack - 1].h);
+        if (g_hash_table_iter_next(&iter, &key, NULL)) {
+            error_set(errp, QERR_QMP_EXTRA_MEMBER, (char *) key);
+        }
+        g_hash_table_unref(qiv->stack[qiv->nb_stack - 1].h);
+    }
+
     assert(qiv->nb_stack > 0);
     qiv->nb_stack--;
 }
@@ -257,3 +289,13 @@ QmpInputVisitor *qmp_input_visitor_new(QObject *obj)
 
     return v;
 }
+
+QmpInputVisitor *qmp_input_visitor_new_strict(QObject *obj)
+{
+    QmpInputVisitor *v;
+
+    v = qmp_input_visitor_new(obj);
+    v->strict = true;
+
+    return v;
+}
diff --git a/qapi/qmp-input-visitor.h b/qapi/qmp-input-visitor.h
index 3f798f0..e0a48a5 100644
--- a/qapi/qmp-input-visitor.h
+++ b/qapi/qmp-input-visitor.h
@@ -20,6 +20,8 @@
 typedef struct QmpInputVisitor QmpInputVisitor;
 
 QmpInputVisitor *qmp_input_visitor_new(QObject *obj);
+QmpInputVisitor *qmp_input_visitor_new_strict(QObject *obj);
+
 void qmp_input_visitor_cleanup(QmpInputVisitor *v);
 
 Visitor *qmp_input_get_visitor(QmpInputVisitor *v);
diff --git a/test-qmp-input-strict.c b/test-qmp-input-strict.c
new file mode 100644
index 0000000..f6df8cb
--- /dev/null
+++ b/test-qmp-input-strict.c
@@ -0,0 +1,234 @@
+/*
+ * QMP Input Visitor unit-tests (strict mode).
+ *
+ * Copyright (C) 2011-2012 Red Hat Inc.
+ *
+ * Authors:
+ *  Luiz Capitulino <lcapitulino@redhat.com>
+ *  Paolo Bonzini <pbonzini@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include <glib.h>
+#include <stdarg.h>
+
+#include "qapi/qmp-input-visitor.h"
+#include "test-qapi-types.h"
+#include "test-qapi-visit.h"
+#include "qemu-objects.h"
+
+typedef struct TestInputVisitorData {
+    QObject *obj;
+    QmpInputVisitor *qiv;
+} TestInputVisitorData;
+
+static void validate_teardown(TestInputVisitorData *data,
+                               const void *unused)
+{
+    qobject_decref(data->obj);
+    data->obj = NULL;
+
+    if (data->qiv) {
+        qmp_input_visitor_cleanup(data->qiv);
+        data->qiv = NULL;
+    }
+}
+
+/* This is provided instead of a test setup function so that the JSON
+   string used by the tests are kept in the test functions (and not
+   int main()) */
+static GCC_FMT_ATTR(2, 3)
+Visitor *validate_test_init(TestInputVisitorData *data,
+                             const char *json_string, ...)
+{
+    Visitor *v;
+    va_list ap;
+
+    va_start(ap, json_string);
+    data->obj = qobject_from_jsonv(json_string, &ap);
+    va_end(ap);
+
+    g_assert(data->obj != NULL);
+
+    data->qiv = qmp_input_visitor_new_strict(data->obj);
+    g_assert(data->qiv != NULL);
+
+    v = qmp_input_get_visitor(data->qiv);
+    g_assert(v != NULL);
+
+    return v;
+}
+
+typedef struct TestStruct
+{
+    int64_t integer;
+    bool boolean;
+    char *string;
+} TestStruct;
+
+static void visit_type_TestStruct(Visitor *v, TestStruct **obj,
+                                  const char *name, Error **errp)
+{
+    visit_start_struct(v, (void **)obj, "TestStruct", name, sizeof(TestStruct),
+                       errp);
+
+    visit_type_int(v, &(*obj)->integer, "integer", errp);
+    visit_type_bool(v, &(*obj)->boolean, "boolean", errp);
+    visit_type_str(v, &(*obj)->string, "string", errp);
+
+    visit_end_struct(v, errp);
+}
+
+static void test_validate_struct(TestInputVisitorData *data,
+                                  const void *unused)
+{
+    TestStruct *p = NULL;
+    Error *errp = NULL;
+    Visitor *v;
+
+    v = validate_test_init(data, "{ 'integer': -42, 'boolean': true, 'string': 'foo' }");
+
+    visit_type_TestStruct(v, &p, NULL, &errp);
+    g_assert(!error_is_set(&errp));
+    g_free(p->string);
+    g_free(p);
+}
+
+static void test_validate_struct_nested(TestInputVisitorData *data,
+                                         const void *unused)
+{
+    UserDefNested *udp = NULL;
+    Error *errp = NULL;
+    Visitor *v;
+
+    v = validate_test_init(data, "{ 'string0': 'string0', 'dict1': { 'string1': 'string1', 'dict2': { 'userdef1': { 'integer': 42, 'string': 'string' }, 'string2': 'string2'}}}");
+
+    visit_type_UserDefNested(v, &udp, NULL, &errp);
+    g_assert(!error_is_set(&errp));
+    qapi_free_UserDefNested(udp);
+}
+
+static void test_validate_list(TestInputVisitorData *data,
+                                const void *unused)
+{
+    UserDefOneList *head = NULL;
+    Error *errp = NULL;
+    Visitor *v;
+
+    v = validate_test_init(data, "[ { 'string': 'string0', 'integer': 42 }, { 'string': 'string1', 'integer': 43 }, { 'string': 'string2', 'integer': 44 } ]");
+
+    visit_type_UserDefOneList(v, &head, NULL, &errp);
+    g_assert(!error_is_set(&errp));
+    qapi_free_UserDefOneList(head);
+}
+
+static void test_validate_union(TestInputVisitorData *data,
+                                 const void *unused)
+{
+    UserDefUnion *tmp = NULL;
+    Visitor *v;
+    Error *errp = NULL;
+
+    v = validate_test_init(data, "{ 'type': 'b', 'data' : { 'integer': 42 } }");
+
+    visit_type_UserDefUnion(v, &tmp, NULL, &errp);
+    g_assert(!error_is_set(&errp));
+    qapi_free_UserDefUnion(tmp);
+}
+
+static void test_validate_fail_struct(TestInputVisitorData *data,
+                                       const void *unused)
+{
+    TestStruct *p = NULL;
+    Error *errp = NULL;
+    Visitor *v;
+
+    v = validate_test_init(data, "{ 'integer': -42, 'boolean': true, 'string': 'foo', 'extra': 42 }");
+
+    visit_type_TestStruct(v, &p, NULL, &errp);
+    g_assert(error_is_set(&errp));
+    if (p) {
+        g_free(p->string);
+    }
+    g_free(p);
+}
+
+static void test_validate_fail_struct_nested(TestInputVisitorData *data,
+                                              const void *unused)
+{
+    UserDefNested *udp = NULL;
+    Error *errp = NULL;
+    Visitor *v;
+
+    v = validate_test_init(data, "{ 'string0': 'string0', 'dict1': { 'string1': 'string1', 'dict2': { 'userdef1': { 'integer': 42, 'string': 'string', 'extra': [42, 23, {'foo':'bar'}] }, 'string2': 'string2'}}}");
+
+    visit_type_UserDefNested(v, &udp, NULL, &errp);
+    g_assert(error_is_set(&errp));
+    qapi_free_UserDefNested(udp);
+}
+
+static void test_validate_fail_list(TestInputVisitorData *data,
+                                     const void *unused)
+{
+    UserDefOneList *head = NULL;
+    Error *errp = NULL;
+    Visitor *v;
+
+    v = validate_test_init(data, "[ { 'string': 'string0', 'integer': 42 }, { 'string': 'string1', 'integer': 43 }, { 'string': 'string2', 'integer': 44, 'extra': 'ggg' } ]");
+
+    visit_type_UserDefOneList(v, &head, NULL, &errp);
+    g_assert(error_is_set(&errp));
+    qapi_free_UserDefOneList(head);
+}
+
+static void test_validate_fail_union(TestInputVisitorData *data,
+                                      const void *unused)
+{
+    UserDefUnion *tmp = NULL;
+    Error *errp = NULL;
+    Visitor *v;
+
+    v = validate_test_init(data, "{ 'type': 'b', 'data' : { 'integer': 42 }, 'extra': 'yyy' }");
+
+    visit_type_UserDefUnion(v, &tmp, NULL, &errp);
+    g_assert(error_is_set(&errp));
+    qapi_free_UserDefUnion(tmp);
+}
+
+static void validate_test_add(const char *testpath,
+                               TestInputVisitorData *data,
+                               void (*test_func)(TestInputVisitorData *data, const void *user_data))
+{
+    g_test_add(testpath, TestInputVisitorData, data, NULL, test_func,
+               validate_teardown);
+}
+
+int main(int argc, char **argv)
+{
+    TestInputVisitorData testdata;
+
+    g_test_init(&argc, &argv, NULL);
+
+    validate_test_add("/visitor/input-strict/pass/struct",
+                       &testdata, test_validate_struct);
+    validate_test_add("/visitor/input-strict/pass/struct-nested",
+                       &testdata, test_validate_struct_nested);
+    validate_test_add("/visitor/input-strict/pass/list",
+                       &testdata, test_validate_list);
+    validate_test_add("/visitor/input-strict/pass/union",
+                       &testdata, test_validate_union);
+    validate_test_add("/visitor/input-strict/fail/struct",
+                       &testdata, test_validate_fail_struct);
+    validate_test_add("/visitor/input-strict/fail/struct-nested",
+                       &testdata, test_validate_fail_struct_nested);
+    validate_test_add("/visitor/input-strict/fail/list",
+                       &testdata, test_validate_fail_list);
+    validate_test_add("/visitor/input-strict/fail/union",
+                       &testdata, test_validate_fail_union);
+
+    g_test_run();
+
+    return 0;
+}
diff --git a/tests/Makefile b/tests/Makefile
index c78ade1..31349f7 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -15,7 +15,7 @@ check-qfloat: check-qfloat.o qfloat.o $(tools-obj-y)
 check-qjson: check-qjson.o $(qobject-obj-y) $(tools-obj-y)
 test-coroutine: test-coroutine.o qemu-timer-common.o async.o $(coroutine-obj-y) $(tools-obj-y)
 
-test-qmp-input-visitor.o test-qmp-output-visitor.o \
+test-qmp-input-visitor.o test-qmp-output-visitor.o test-qmp-input-strict.o \
 test-string-input-visitor.o test-string-output-visitor.o \
 	test-qmp-commands.o qemu-ga$(EXESUF): QEMU_CFLAGS += -I $(qapi-dir)
 
@@ -36,6 +36,9 @@ test-string-output-visitor: test-string-output-visitor.o $(qobject-obj-y) $(qapi
 test-string-input-visitor.o: $(addprefix $(qapi-dir)/, test-qapi-types.c test-qapi-types.h test-qapi-visit.c test-qapi-visit.h) $(qapi-obj-y)
 test-string-input-visitor: test-string-input-visitor.o $(qobject-obj-y) $(qapi-obj-y) $(tools-obj-y) $(qapi-dir)/test-qapi-visit.o $(qapi-dir)/test-qapi-types.o
 
+test-qmp-input-strict.o: $(addprefix $(qapi-dir)/, test-qapi-types.c test-qapi-types.h test-qapi-visit.c test-qapi-visit.h) $(qapi-obj-y)
+test-qmp-input-strict: test-qmp-input-strict.o $(qobject-obj-y) $(qapi-obj-y) $(tools-obj-y) $(qapi-dir)/test-qapi-visit.o $(qapi-dir)/test-qapi-types.o
+
 test-qmp-output-visitor.o: $(addprefix $(qapi-dir)/, test-qapi-types.c test-qapi-types.h test-qapi-visit.c test-qapi-visit.h) $(qapi-obj-y)
 test-qmp-output-visitor: test-qmp-output-visitor.o $(qobject-obj-y) $(qapi-obj-y) $(tools-obj-y) $(qapi-dir)/test-qapi-visit.o $(qapi-dir)/test-qapi-types.o
 
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