1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "net/cert/test_root_certs.h"
6
7 #include <windows.h>
8 #include <wincrypt.h>
9
10 #include "base/basictypes.h"
11 #include "base/lazy_instance.h"
12 #include "base/logging.h"
13 #include "base/win/win_util.h"
14 #include "base/win/windows_version.h"
15 #include "net/cert/x509_certificate.h"
16
17 namespace net {
18
19 namespace {
20
21 // Provides a CertDllOpenStoreProv callback provider function, to be called
22 // by CertOpenStore when the CERT_STORE_PROV_SYSTEM_W store is opened. See
23 // http://msdn.microsoft.com/en-us/library/aa376043(VS.85).aspx.
24 BOOL WINAPI InterceptedOpenStoreW(LPCSTR store_provider,
25 DWORD encoding,
26 HCRYPTPROV crypt_provider,
27 DWORD flags,
28 const void* extra,
29 HCERTSTORE memory_store,
30 PCERT_STORE_PROV_INFO store_info);
31
32 // CryptoAPIInjector is used to inject a store provider function for system
33 // certificate stores before the one provided internally by Crypt32.dll.
34 // Once injected, there is no way to remove, so every call to open a system
35 // store will be redirected to the injected function.
36 struct CryptoAPIInjector {
37 // The previous default function for opening system stores. For most
38 // configurations, this should point to Crypt32's internal
39 // I_CertDllOpenSystemStoreProvW function.
40 PFN_CERT_DLL_OPEN_STORE_PROV_FUNC original_function;
41
42 // The handle that CryptoAPI uses to ensure the DLL implementing
43 // |original_function| remains loaded in memory.
44 HCRYPTOIDFUNCADDR original_handle;
45
46 private:
47 friend struct base::DefaultLazyInstanceTraits<CryptoAPIInjector>;
48
CryptoAPIInjectornet::__anonbe0b148c0111::CryptoAPIInjector49 CryptoAPIInjector()
50 : original_function(NULL),
51 original_handle(NULL) {
52 HCRYPTOIDFUNCSET registered_functions =
53 CryptInitOIDFunctionSet(CRYPT_OID_OPEN_STORE_PROV_FUNC, 0);
54
55 // Preserve the original handler function in |original_function|. If other
56 // functions are overridden, they will also need to be preserved.
57 BOOL ok = CryptGetOIDFunctionAddress(
58 registered_functions, 0, CERT_STORE_PROV_SYSTEM_W, 0,
59 reinterpret_cast<void**>(&original_function), &original_handle);
60 DCHECK(ok);
61
62 // For now, intercept only the numeric form of the system store
63 // function, CERT_STORE_PROV_SYSTEM_W (0x0A), which is what Crypt32
64 // functionality uses exclusively. Depending on the machine that tests
65 // are being run on, it may prove necessary to also intercept
66 // sz_CERT_STORE_PROV_SYSTEM_[A/W] and CERT_STORE_PROV_SYSTEM_A, based
67 // on whether or not any third-party CryptoAPI modules have been
68 // installed.
69 const CRYPT_OID_FUNC_ENTRY kFunctionToIntercept =
70 { CERT_STORE_PROV_SYSTEM_W, &InterceptedOpenStoreW };
71
72 // Inject kFunctionToIntercept at the front of the linked list that
73 // crypt32 uses when CertOpenStore is called, replacing the existing
74 // registered function.
75 ok = CryptInstallOIDFunctionAddress(NULL, 0,
76 CRYPT_OID_OPEN_STORE_PROV_FUNC, 1,
77 &kFunctionToIntercept,
78 CRYPT_INSTALL_OID_FUNC_BEFORE_FLAG);
79 DCHECK(ok);
80 }
81
82 // This is never called, because this object is intentionally leaked.
83 // Certificate verification happens on a non-joinable worker thread, which
84 // may still be running when ~AtExitManager is called, so the LazyInstance
85 // must be leaky.
~CryptoAPIInjectornet::__anonbe0b148c0111::CryptoAPIInjector86 ~CryptoAPIInjector() {
87 original_function = NULL;
88 CryptFreeOIDFunctionAddress(original_handle, NULL);
89 }
90 };
91
92 base::LazyInstance<CryptoAPIInjector>::Leaky
93 g_capi_injector = LAZY_INSTANCE_INITIALIZER;
94
InterceptedOpenStoreW(LPCSTR store_provider,DWORD encoding,HCRYPTPROV crypt_provider,DWORD flags,const void * store_name,HCERTSTORE memory_store,PCERT_STORE_PROV_INFO store_info)95 BOOL WINAPI InterceptedOpenStoreW(LPCSTR store_provider,
96 DWORD encoding,
97 HCRYPTPROV crypt_provider,
98 DWORD flags,
99 const void* store_name,
100 HCERTSTORE memory_store,
101 PCERT_STORE_PROV_INFO store_info) {
102 // If the high word is all zeroes, then |store_provider| is a numeric ID.
103 // Otherwise, it's a pointer to a null-terminated ASCII string. See the
104 // documentation for CryptGetOIDFunctionAddress for more information.
105 uint32 store_as_uint = reinterpret_cast<uint32>(store_provider);
106 if (store_as_uint > 0xFFFF || store_provider != CERT_STORE_PROV_SYSTEM_W ||
107 !g_capi_injector.Get().original_function)
108 return FALSE;
109
110 BOOL ok = g_capi_injector.Get().original_function(store_provider, encoding,
111 crypt_provider, flags,
112 store_name, memory_store,
113 store_info);
114 // Only the Root store should have certificates injected. If
115 // CERT_SYSTEM_STORE_RELOCATE_FLAG is set, then |store_name| points to a
116 // CERT_SYSTEM_STORE_RELOCATE_PARA structure, rather than a
117 // NULL-terminated wide string, so check before making a string
118 // comparison.
119 if (!ok || TestRootCerts::GetInstance()->IsEmpty() ||
120 (flags & CERT_SYSTEM_STORE_RELOCATE_FLAG) ||
121 lstrcmpiW(reinterpret_cast<LPCWSTR>(store_name), L"root"))
122 return ok;
123
124 // The result of CertOpenStore with CERT_STORE_PROV_SYSTEM_W is documented
125 // to be a collection store, and that appears to hold for |memory_store|.
126 // Attempting to add an individual certificate to |memory_store| causes
127 // the request to be forwarded to the first physical store in the
128 // collection that accepts modifications, which will cause a secure
129 // confirmation dialog to be displayed, confirming the user wishes to
130 // trust the certificate. However, appending a store to the collection
131 // will merely modify the temporary collection store, and will not persist
132 // any changes to the underlying physical store. When the |memory_store| is
133 // searched to see if a certificate is in the Root store, all the
134 // underlying stores in the collection will be searched, and any certificate
135 // in temporary_roots() will be found and seen as trusted.
136 return CertAddStoreToCollection(
137 memory_store, TestRootCerts::GetInstance()->temporary_roots(), 0, 0);
138 }
139
140 } // namespace
141
Add(X509Certificate * certificate)142 bool TestRootCerts::Add(X509Certificate* certificate) {
143 // Ensure that the default CryptoAPI functionality has been intercepted.
144 // If a test certificate is never added, then no interception should
145 // happen.
146 g_capi_injector.Get();
147
148 BOOL ok = CertAddCertificateContextToStore(
149 temporary_roots_, certificate->os_cert_handle(),
150 CERT_STORE_ADD_NEW, NULL);
151 if (!ok) {
152 // If the certificate is already added, return successfully.
153 return GetLastError() == CRYPT_E_EXISTS;
154 }
155
156 empty_ = false;
157 return true;
158 }
159
Clear()160 void TestRootCerts::Clear() {
161 empty_ = true;
162
163 PCCERT_CONTEXT prev_cert = NULL;
164 while (prev_cert = CertEnumCertificatesInStore(temporary_roots_, NULL))
165 CertDeleteCertificateFromStore(prev_cert);
166 }
167
IsEmpty() const168 bool TestRootCerts::IsEmpty() const {
169 return empty_;
170 }
171
GetChainEngine() const172 HCERTCHAINENGINE TestRootCerts::GetChainEngine() const {
173 if (IsEmpty())
174 return NULL; // Default chain engine will suffice.
175
176 // Windows versions before 7 don't accept the struct size for later versions.
177 // We report the size of the old struct since we don't need the new members.
178 static const DWORD kSizeofCertChainEngineConfig =
179 SIZEOF_STRUCT_WITH_SPECIFIED_LAST_MEMBER(
180 CERT_CHAIN_ENGINE_CONFIG, CycleDetectionModulus);
181
182 // Each HCERTCHAINENGINE caches both the configured system stores and
183 // information about each chain that has been built. In order to ensure
184 // that changes to |temporary_roots_| are properly propagated and that the
185 // various caches are flushed, when at least one certificate is added,
186 // return a new chain engine for every call. Each chain engine creation
187 // should re-open the root store, ensuring the most recent changes are
188 // visible.
189 CERT_CHAIN_ENGINE_CONFIG engine_config = {
190 kSizeofCertChainEngineConfig
191 };
192 engine_config.dwFlags =
193 CERT_CHAIN_ENABLE_CACHE_AUTO_UPDATE |
194 CERT_CHAIN_ENABLE_SHARE_STORE;
195 HCERTCHAINENGINE chain_engine = NULL;
196 BOOL ok = CertCreateCertificateChainEngine(&engine_config, &chain_engine);
197 DCHECK(ok);
198 return chain_engine;
199 }
200
~TestRootCerts()201 TestRootCerts::~TestRootCerts() {
202 CertCloseStore(temporary_roots_, 0);
203 }
204
Init()205 void TestRootCerts::Init() {
206 empty_ = true;
207 temporary_roots_ = CertOpenStore(
208 CERT_STORE_PROV_MEMORY, 0, NULL,
209 CERT_STORE_DEFER_CLOSE_UNTIL_LAST_FREE_FLAG, NULL);
210 DCHECK(temporary_roots_);
211 }
212
213 } // namespace net
214