[Qemu-devel] [PATCH v2 3/4] tests: add QMP input visitor test for unions with no discriminator

[Michael Roth <mdroth@linux.vnet.ibm.com>]

This more of an exercise of the dealloc visitor, where it may
erroneously use an uninitialized discriminator field as indication
that union fields corresponding to that discriminator field/type are
present, which can lead to attempts to free random chunks of heap
memory.

Cc: qemu-stable@nongnu.org
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 tests/qapi-schema/qapi-schema-test.json | 10 ++++++++++
 tests/qapi-schema/qapi-schema-test.out  |  3 +++
 tests/test-qmp-input-strict.c           | 17 +++++++++++++++++
 3 files changed, 30 insertions(+)

diff --git a/tests/qapi-schema/qapi-schema-test.json b/tests/qapi-schema/qapi-schema-test.json
index ab4d3d9..d43b5fd 100644
--- a/tests/qapi-schema/qapi-schema-test.json
+++ b/tests/qapi-schema/qapi-schema-test.json
@@ -33,6 +33,9 @@
 { 'type': 'UserDefB',
   'data': { 'integer': 'int' } }
 
+{ 'type': 'UserDefC',
+  'data': { 'string1': 'str', 'string2': 'str' } }
+
 { 'union': 'UserDefUnion',
   'base': 'UserDefZero',
   'data': { 'a' : 'UserDefA', 'b' : 'UserDefB' } }
@@ -47,6 +50,13 @@
 # FIXME generated struct UserDefFlatUnion has members for direct base
 # UserDefOne, but lacks members for indirect base UserDefZero
 
+# this variant of UserDefFlatUnion defaults to a union that uses fields with
+# allocated types to test corner cases in the cleanup/dealloc visitor
+{ 'union': 'UserDefFlatUnion2',
+  'base': 'UserDefUnionBase',
+  'discriminator': 'enum1',
+  'data': { 'value1' : 'UserDefC', 'value2' : 'UserDefB', 'value3' : 'UserDefA' } }
+
 { 'union': 'UserDefAnonUnion',
   'discriminator': {},
   'data': { 'uda': 'UserDefA', 's': 'str', 'i': 'int' } }
diff --git a/tests/qapi-schema/qapi-schema-test.out b/tests/qapi-schema/qapi-schema-test.out
index 95e9899..08d7304 100644
--- a/tests/qapi-schema/qapi-schema-test.out
+++ b/tests/qapi-schema/qapi-schema-test.out
@@ -6,9 +6,11 @@
  OrderedDict([('type', 'UserDefNested'), ('data', OrderedDict([('string0', 'str'), ('dict1', OrderedDict([('string1', 'str'), ('dict2', OrderedDict([('userdef1', 'UserDefOne'), ('string2', 'str')])), ('*dict3', OrderedDict([('userdef2', 'UserDefOne'), ('string3', 'str')]))]))]))]),
  OrderedDict([('type', 'UserDefA'), ('data', OrderedDict([('boolean', 'bool')]))]),
  OrderedDict([('type', 'UserDefB'), ('data', OrderedDict([('integer', 'int')]))]),
+ OrderedDict([('type', 'UserDefC'), ('data', OrderedDict([('string1', 'str'), ('string2', 'str')]))]),
  OrderedDict([('union', 'UserDefUnion'), ('base', 'UserDefZero'), ('data', OrderedDict([('a', 'UserDefA'), ('b', 'UserDefB')]))]),
  OrderedDict([('type', 'UserDefUnionBase'), ('data', OrderedDict([('string', 'str'), ('enum1', 'EnumOne')]))]),
  OrderedDict([('union', 'UserDefFlatUnion'), ('base', 'UserDefUnionBase'), ('discriminator', 'enum1'), ('data', OrderedDict([('value1', 'UserDefA'), ('value2', 'UserDefB'), ('value3', 'UserDefB')]))]),
+ OrderedDict([('union', 'UserDefFlatUnion2'), ('base', 'UserDefUnionBase'), ('discriminator', 'enum1'), ('data', OrderedDict([('value1', 'UserDefC'), ('value2', 'UserDefB'), ('value3', 'UserDefA')]))]),
  OrderedDict([('union', 'UserDefAnonUnion'), ('discriminator', OrderedDict()), ('data', OrderedDict([('uda', 'UserDefA'), ('s', 'str'), ('i', 'int')]))]),
  OrderedDict([('union', 'UserDefNativeListUnion'), ('data', OrderedDict([('integer', ['int']), ('s8', ['int8']), ('s16', ['int16']), ('s32', ['int32']), ('s64', ['int64']), ('u8', ['uint8']), ('u16', ['uint16']), ('u32', ['uint32']), ('u64', ['uint64']), ('number', ['number']), ('boolean', ['bool']), ('string', ['str'])]))]),
  OrderedDict([('command', 'user_def_cmd'), ('data', OrderedDict())]),
@@ -32,6 +34,7 @@
  OrderedDict([('type', 'UserDefNested'), ('data', OrderedDict([('string0', 'str'), ('dict1', OrderedDict([('string1', 'str'), ('dict2', OrderedDict([('userdef1', 'UserDefOne'), ('string2', 'str')])), ('*dict3', OrderedDict([('userdef2', 'UserDefOne'), ('string3', 'str')]))]))]))]),
  OrderedDict([('type', 'UserDefA'), ('data', OrderedDict([('boolean', 'bool')]))]),
  OrderedDict([('type', 'UserDefB'), ('data', OrderedDict([('integer', 'int')]))]),
+ OrderedDict([('type', 'UserDefC'), ('data', OrderedDict([('string1', 'str'), ('string2', 'str')]))]),
  OrderedDict([('type', 'UserDefUnionBase'), ('data', OrderedDict([('string', 'str'), ('enum1', 'EnumOne')]))]),
  OrderedDict([('type', 'UserDefOptions'), ('data', OrderedDict([('*i64', ['int']), ('*u64', ['uint64']), ('*u16', ['uint16']), ('*i64x', 'int'), ('*u64x', 'uint64')]))]),
  OrderedDict([('type', 'EventStructOne'), ('data', OrderedDict([('struct1', 'UserDefOne'), ('string', 'str'), ('*enum2', 'EnumOne')]))])]
diff --git a/tests/test-qmp-input-strict.c b/tests/test-qmp-input-strict.c
index 0f77003..d5360c6 100644
--- a/tests/test-qmp-input-strict.c
+++ b/tests/test-qmp-input-strict.c
@@ -260,6 +260,21 @@ static void test_validate_fail_union_flat(TestInputVisitorData *data,
     qapi_free_UserDefFlatUnion(tmp);
 }
 
+static void test_validate_fail_union_flat_no_discrim(TestInputVisitorData *data,
+                                                     const void *unused)
+{
+    UserDefFlatUnion2 *tmp = NULL;
+    Error *err = NULL;
+    Visitor *v;
+
+    /* test situation where discriminator field ('enum1' here) is missing */
+    v = validate_test_init(data, "{ 'string': 'c', 'string1': 'd', 'string2': 'e' }");
+
+    visit_type_UserDefFlatUnion2(v, &tmp, NULL, &err);
+    g_assert(err);
+    qapi_free_UserDefFlatUnion2(tmp);
+}
+
 static void test_validate_fail_union_anon(TestInputVisitorData *data,
                                           const void *unused)
 {
@@ -310,6 +325,8 @@ int main(int argc, char **argv)
                        &testdata, test_validate_fail_union);
     validate_test_add("/visitor/input-strict/fail/union-flat",
                        &testdata, test_validate_fail_union_flat);
+    validate_test_add("/visitor/input-strict/fail/union-flat-no-discriminator",
+                       &testdata, test_validate_fail_union_flat_no_discrim);
     validate_test_add("/visitor/input-strict/fail/union-anon",
                        &testdata, test_validate_fail_union_anon);
 
-- 
1.9.1