1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
#ifndef LO_CLANG_SHARED_PLUGINS
#include "check.hxx"
#include "plugin.hxx"
/* OWeakObject::release() disposes weak references. If that isn't done
* because a sub-class improperly overrides release() then
* OWeakConnectionPoint::m_pObject continues to point to the deleted object
* and that could result in use-after-free.
*/
namespace {
class WeakObject
: public loplugin::FilteringPlugin<WeakObject>
{
public:
explicit WeakObject(loplugin::InstantiationData const& rData): FilteringPlugin(rData)
{}
virtual bool preRun() override {
return compiler.getLangOpts().CPlusPlus; // no OWeakObject in C
}
void run() override {
if( preRun()) {
TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
}
}
bool isDerivedFromOWeakObject(CXXMethodDecl const*const pMethodDecl)
{
QualType const pClass(pMethodDecl->getParent()->getTypeForDecl(), 0);
if (loplugin::TypeCheck(pClass).Class("OWeakObject").Namespace("cppu"))
{
return true;
}
// hopefully it's faster to recurse overridden methods than the
// thicket of WeakImplHelper32 but that is purely speculation
for (auto it = pMethodDecl->begin_overridden_methods();
it != pMethodDecl->end_overridden_methods(); ++it)
{
if (isDerivedFromOWeakObject(*it))
{
return true;
}
}
return false;
}
bool VisitCXXMethodDecl(CXXMethodDecl const*const pMethodDecl)
{
if (ignoreLocation(pMethodDecl)) {
return true;
}
if (!pMethodDecl->isThisDeclarationADefinition()
|| pMethodDecl->isLateTemplateParsed())
{
return true;
}
if (!pMethodDecl->isInstance()) {
return true;
}
// this is too "simple", if a NamedDecl class has a getName() member expecting it to actually work would clearly be unreasonable if (pMethodDecl->getName() != "release") {
if (auto const i = pMethodDecl->getIdentifier()) {
if (i != nullptr && !i->isStr("release")) {
return true;
}
}
if (pMethodDecl->getNumParams() != 0) {
return true;
}
if (loplugin::TypeCheck(QualType(pMethodDecl->getParent()->getTypeForDecl(), 0)).Class("OWeakObject").Namespace("cppu"))
{
return true;
}
CXXMethodDecl const* pOverridden(nullptr);
for (auto it = pMethodDecl->begin_overridden_methods();
it != pMethodDecl->end_overridden_methods(); ++it)
{
if (auto const i = (*it)->getIdentifier()) {
if (i != nullptr && i->isStr("release")) {
pOverridden = *it;
break;
}
}
}
if (pOverridden == nullptr)
{
return true;
}
if (!isDerivedFromOWeakObject(pOverridden))
{
return true;
}
CompoundStmt const*const pCompoundStatement(
dyn_cast<CompoundStmt>(pMethodDecl->getBody()));
for (auto i = pCompoundStatement->body_begin();
i != pCompoundStatement->body_end(); ++i)
{
// note: this is not a CXXMemberCallExpr
CallExpr const*const pCallExpr(dyn_cast<CallExpr>(*i));
if (pCallExpr)
{
// note: this is only sometimes a CXXMethodDecl
FunctionDecl const*const pCalled(pCallExpr->getDirectCallee());
if (pCalled->getName() == "release")
{
//this never works && pCalled == pOverridden
if (pCalled->getParent() == pOverridden->getParent())
{
return true;
}
// Allow this convenient shortcut:
auto td = dyn_cast<TypeDecl>(pCalled->getParent());
if (td != nullptr
&& (loplugin::TypeCheck(td).Class("OWeakObject").Namespace("cppu").GlobalNamespace()
|| loplugin::TypeCheck(td).Class("OWeakAggObject").Namespace("cppu").GlobalNamespace()))
{
return true;
}
}
}
}
// whitelist
auto tc = loplugin::TypeCheck(pMethodDecl->getParent());
if ( tc.Class("OWeakAggObject").Namespace("cppu").GlobalNamespace() // conditional call
|| tc.Class("WeakComponentImplHelperBase").Namespace("cppu").GlobalNamespace() // extra magic
|| tc.Class("WeakAggComponentImplHelperBase").Namespace("cppu").GlobalNamespace() // extra magic
|| tc.Class("CDOMImplementation").Namespace("DOM").GlobalNamespace() // a static oddity
|| tc.Class("SwXTextFrame").GlobalNamespace() // ambiguous, 3 parents
|| tc.Class("SwXTextDocument").GlobalNamespace() // ambiguous, ~4 parents
|| tc.Class("SdStyleSheet").GlobalNamespace() // same extra magic as WeakComponentImplHelperBase
|| tc.Class("SdXImpressDocument").GlobalNamespace() // same extra magic as WeakComponentImplHelperBase
)
{
return true;
}
report(DiagnosticsEngine::Warning,
"override of OWeakObject::release() does not call superclass release()",
pMethodDecl->getLocation())
<< pMethodDecl->getSourceRange();
return true;
}
};
loplugin::Plugin::Registration<WeakObject> weakobject("weakobject");
} // namespace
#endif // LO_CLANG_SHARED_PLUGINS
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */