1 // Copyright 2013 The Chromium Authors
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/ssl/client_cert_store_win.h"
6
7 #include <algorithm>
8 #include <functional>
9 #include <memory>
10 #include <string>
11
12 #include <windows.h>
13
14 #define SECURITY_WIN32
15 #include <security.h>
16
17 #include "base/functional/bind.h"
18 #include "base/functional/callback.h"
19 #include "base/functional/callback_helpers.h"
20 #include "base/logging.h"
21 #include "base/numerics/safe_conversions.h"
22 #include "base/scoped_generic.h"
23 #include "base/task/single_thread_task_runner.h"
24 #include "base/win/wincrypt_shim.h"
25 #include "net/cert/x509_util.h"
26 #include "net/cert/x509_util_win.h"
27 #include "net/ssl/ssl_platform_key_util.h"
28 #include "net/ssl/ssl_platform_key_win.h"
29 #include "net/ssl/ssl_private_key.h"
30 #include "third_party/boringssl/src/include/openssl/pool.h"
31
32 namespace net {
33
34 namespace {
35
36 using ScopedHCERTSTOREWithChecks = base::ScopedGeneric<
37 HCERTSTORE,
38 crypto::CAPITraitsWithFlags<HCERTSTORE,
39 CertCloseStore,
40 CERT_CLOSE_STORE_CHECK_FLAG>>;
41
42 class ClientCertIdentityWin : public ClientCertIdentity {
43 public:
ClientCertIdentityWin(scoped_refptr<net::X509Certificate> cert,crypto::ScopedPCCERT_CONTEXT cert_context,scoped_refptr<base::SingleThreadTaskRunner> key_task_runner)44 ClientCertIdentityWin(
45 scoped_refptr<net::X509Certificate> cert,
46 crypto::ScopedPCCERT_CONTEXT cert_context,
47 scoped_refptr<base::SingleThreadTaskRunner> key_task_runner)
48 : ClientCertIdentity(std::move(cert)),
49 cert_context_(std::move(cert_context)),
50 key_task_runner_(std::move(key_task_runner)) {}
51
AcquirePrivateKey(base::OnceCallback<void (scoped_refptr<SSLPrivateKey>)> private_key_callback)52 void AcquirePrivateKey(base::OnceCallback<void(scoped_refptr<SSLPrivateKey>)>
53 private_key_callback) override {
54 key_task_runner_->PostTaskAndReplyWithResult(
55 FROM_HERE,
56 base::BindOnce(&FetchClientCertPrivateKey,
57 base::Unretained(certificate()), cert_context_.get()),
58 std::move(private_key_callback));
59 }
60
61 private:
62 crypto::ScopedPCCERT_CONTEXT cert_context_;
63 scoped_refptr<base::SingleThreadTaskRunner> key_task_runner_;
64 };
65
66 // Callback required by Windows API function CertFindChainInStore(). In addition
67 // to filtering by extended/enhanced key usage, we do not show expired
68 // certificates and require digital signature usage in the key usage extension.
69 //
70 // This matches our behavior on Mac OS X and that of NSS. It also matches the
71 // default behavior of IE8. See http://support.microsoft.com/kb/890326 and
72 // http://blogs.msdn.com/b/askie/archive/2009/06/09/my-expired-client-certifica
73 // tes-no-longer-display-when-connecting-to-my-web-server-using-ie8.aspx
ClientCertFindCallback(PCCERT_CONTEXT cert_context,void * find_arg)74 static BOOL WINAPI ClientCertFindCallback(PCCERT_CONTEXT cert_context,
75 void* find_arg) {
76 // Verify the certificate key usage is appropriate or not specified.
77 BYTE key_usage;
78 if (CertGetIntendedKeyUsage(X509_ASN_ENCODING, cert_context->pCertInfo,
79 &key_usage, 1)) {
80 if (!(key_usage & CERT_DIGITAL_SIGNATURE_KEY_USAGE))
81 return FALSE;
82 } else {
83 DWORD err = GetLastError();
84 // If |err| is non-zero, it's an actual error. Otherwise the extension
85 // just isn't present, and we treat it as if everything was allowed.
86 if (err) {
87 DLOG(ERROR) << "CertGetIntendedKeyUsage failed: " << err;
88 return FALSE;
89 }
90 }
91
92 // Verify the current time is within the certificate's validity period.
93 if (CertVerifyTimeValidity(nullptr, cert_context->pCertInfo) != 0)
94 return FALSE;
95
96 // Verify private key metadata is associated with this certificate.
97 // TODO(ppi): Is this really needed? Isn't it equivalent to leaving
98 // CERT_CHAIN_FIND_BY_ISSUER_NO_KEY_FLAG not set in |find_flags| argument of
99 // CertFindChainInStore()?
100 DWORD size = 0;
101 if (!CertGetCertificateContextProperty(
102 cert_context, CERT_KEY_PROV_INFO_PROP_ID, nullptr, &size)) {
103 return FALSE;
104 }
105
106 return TRUE;
107 }
108
GetClientCertsImpl(HCERTSTORE cert_store,const SSLCertRequestInfo & request)109 ClientCertIdentityList GetClientCertsImpl(HCERTSTORE cert_store,
110 const SSLCertRequestInfo& request) {
111 ClientCertIdentityList selected_identities;
112
113 scoped_refptr<base::SingleThreadTaskRunner> current_thread =
114 base::SingleThreadTaskRunner::GetCurrentDefault();
115
116 const size_t auth_count = request.cert_authorities.size();
117 std::vector<CERT_NAME_BLOB> issuers(auth_count);
118 for (size_t i = 0; i < auth_count; ++i) {
119 issuers[i].cbData = static_cast<DWORD>(request.cert_authorities[i].size());
120 issuers[i].pbData = reinterpret_cast<BYTE*>(
121 const_cast<char*>(request.cert_authorities[i].data()));
122 }
123
124 // Enumerate the client certificates.
125 CERT_CHAIN_FIND_BY_ISSUER_PARA find_by_issuer_para;
126 memset(&find_by_issuer_para, 0, sizeof(find_by_issuer_para));
127 find_by_issuer_para.cbSize = sizeof(find_by_issuer_para);
128 find_by_issuer_para.pszUsageIdentifier = szOID_PKIX_KP_CLIENT_AUTH;
129 find_by_issuer_para.cIssuer = static_cast<DWORD>(auth_count);
130 find_by_issuer_para.rgIssuer =
131 reinterpret_cast<CERT_NAME_BLOB*>(issuers.data());
132 find_by_issuer_para.pfnFindCallback = ClientCertFindCallback;
133
134 PCCERT_CHAIN_CONTEXT chain_context = nullptr;
135 DWORD find_flags = CERT_CHAIN_FIND_BY_ISSUER_CACHE_ONLY_FLAG |
136 CERT_CHAIN_FIND_BY_ISSUER_CACHE_ONLY_URL_FLAG;
137 for (;;) {
138 // Find a certificate chain.
139 chain_context = CertFindChainInStore(cert_store,
140 X509_ASN_ENCODING,
141 find_flags,
142 CERT_CHAIN_FIND_BY_ISSUER,
143 &find_by_issuer_para,
144 chain_context);
145 if (!chain_context) {
146 if (GetLastError() != static_cast<DWORD>(CRYPT_E_NOT_FOUND))
147 DPLOG(ERROR) << "CertFindChainInStore failed: ";
148 break;
149 }
150
151 // Get the leaf certificate.
152 PCCERT_CONTEXT cert_context =
153 chain_context->rgpChain[0]->rgpElement[0]->pCertContext;
154 // Copy the certificate, so that it is valid after |cert_store| is closed.
155 crypto::ScopedPCCERT_CONTEXT cert_context2;
156 PCCERT_CONTEXT raw = nullptr;
157 BOOL ok = CertAddCertificateContextToStore(
158 nullptr, cert_context, CERT_STORE_ADD_USE_EXISTING, &raw);
159 if (!ok) {
160 NOTREACHED();
161 continue;
162 }
163 cert_context2.reset(raw);
164
165 // Grab the intermediates, if any.
166 std::vector<crypto::ScopedPCCERT_CONTEXT> intermediates_storage;
167 std::vector<PCCERT_CONTEXT> intermediates;
168 for (DWORD i = 1; i < chain_context->rgpChain[0]->cElement; ++i) {
169 PCCERT_CONTEXT chain_intermediate =
170 chain_context->rgpChain[0]->rgpElement[i]->pCertContext;
171 PCCERT_CONTEXT copied_intermediate = nullptr;
172 ok = CertAddCertificateContextToStore(nullptr, chain_intermediate,
173 CERT_STORE_ADD_USE_EXISTING,
174 &copied_intermediate);
175 if (ok) {
176 intermediates.push_back(copied_intermediate);
177 intermediates_storage.emplace_back(copied_intermediate);
178 }
179 }
180
181 // Drop the self-signed root, if any. Match Internet Explorer in not sending
182 // it. Although the root's signature is irrelevant for authentication, some
183 // servers reject chains if the root is explicitly sent and has a weak
184 // signature algorithm. See https://crbug.com/607264.
185 //
186 // The leaf or a intermediate may also have a weak signature algorithm but,
187 // in that case, assume it is a configuration error.
188 if (!intermediates.empty() &&
189 x509_util::IsSelfSigned(intermediates.back())) {
190 intermediates.pop_back();
191 intermediates_storage.pop_back();
192 }
193
194 // Allow UTF-8 inside PrintableStrings in client certificates. See
195 // crbug.com/770323.
196 X509Certificate::UnsafeCreateOptions options;
197 options.printable_string_is_utf8 = true;
198 scoped_refptr<X509Certificate> cert =
199 x509_util::CreateX509CertificateFromCertContexts(
200 cert_context2.get(), intermediates, options);
201 if (cert) {
202 selected_identities.push_back(std::make_unique<ClientCertIdentityWin>(
203 std::move(cert),
204 std::move(cert_context2), // Takes ownership of |cert_context2|.
205 current_thread)); // The key must be acquired on the same thread, as
206 // the PCCERT_CONTEXT may not be thread safe.
207 }
208 }
209
210 std::sort(selected_identities.begin(), selected_identities.end(),
211 ClientCertIdentitySorter());
212 return selected_identities;
213 }
214
215 } // namespace
216
217 ClientCertStoreWin::ClientCertStoreWin() = default;
218
ClientCertStoreWin(base::RepeatingCallback<crypto::ScopedHCERTSTORE ()> cert_store_callback)219 ClientCertStoreWin::ClientCertStoreWin(
220 base::RepeatingCallback<crypto::ScopedHCERTSTORE()> cert_store_callback)
221 : cert_store_callback_(std::move(cert_store_callback)) {
222 DCHECK(!cert_store_callback_.is_null());
223 }
224
225 ClientCertStoreWin::~ClientCertStoreWin() = default;
226
GetClientCerts(const SSLCertRequestInfo & request,ClientCertListCallback callback)227 void ClientCertStoreWin::GetClientCerts(const SSLCertRequestInfo& request,
228 ClientCertListCallback callback) {
229 GetSSLPlatformKeyTaskRunner()->PostTaskAndReplyWithResult(
230 FROM_HERE,
231 // Caller is responsible for keeping the |request| alive
232 // until the callback is run, so std::cref is safe.
233 base::BindOnce(&ClientCertStoreWin::GetClientCertsWithCertStore,
234 std::cref(request), cert_store_callback_),
235 std::move(callback));
236 }
237
238 // static
GetClientCertsWithCertStore(const SSLCertRequestInfo & request,const base::RepeatingCallback<crypto::ScopedHCERTSTORE ()> & cert_store_callback)239 ClientCertIdentityList ClientCertStoreWin::GetClientCertsWithCertStore(
240 const SSLCertRequestInfo& request,
241 const base::RepeatingCallback<crypto::ScopedHCERTSTORE()>&
242 cert_store_callback) {
243 ScopedHCERTSTOREWithChecks cert_store;
244 if (cert_store_callback.is_null()) {
245 // Always open a new instance of the "MY" store, to ensure that there
246 // are no previously cached certificates being reused after they're
247 // no longer available (some smartcard providers fail to update the "MY"
248 // store handles and instead interpose CertOpenSystemStore). To help confirm
249 // this, use `ScopedHCERTSTOREWithChecks` and `CERT_CLOSE_STORE_CHECK_FLAG`
250 // to DCHECK that `cert_store` is not inadvertently ref-counted.
251 cert_store.reset(CertOpenSystemStore(NULL, L"MY"));
252 } else {
253 cert_store.reset(cert_store_callback.Run().release());
254 }
255 if (!cert_store.is_valid()) {
256 PLOG(ERROR) << "Could not open certificate store: ";
257 return ClientCertIdentityList();
258 }
259 return GetClientCertsImpl(cert_store.get(), request);
260 }
261
SelectClientCertsForTesting(const CertificateList & input_certs,const SSLCertRequestInfo & request,ClientCertIdentityList * selected_identities)262 bool ClientCertStoreWin::SelectClientCertsForTesting(
263 const CertificateList& input_certs,
264 const SSLCertRequestInfo& request,
265 ClientCertIdentityList* selected_identities) {
266 ScopedHCERTSTOREWithChecks test_store(
267 CertOpenStore(CERT_STORE_PROV_MEMORY, 0, NULL, 0, nullptr));
268 if (!test_store.is_valid())
269 return false;
270
271 // Add available certificates to the test store.
272 for (const auto& input_cert : input_certs) {
273 // Add the certificate to the test store.
274 PCCERT_CONTEXT cert = nullptr;
275 if (!CertAddEncodedCertificateToStore(
276 test_store.get(), X509_ASN_ENCODING,
277 reinterpret_cast<const BYTE*>(
278 CRYPTO_BUFFER_data(input_cert->cert_buffer())),
279 base::checked_cast<DWORD>(
280 CRYPTO_BUFFER_len(input_cert->cert_buffer())),
281 CERT_STORE_ADD_NEW, &cert)) {
282 return false;
283 }
284 // Hold the reference to the certificate (since we requested a copy).
285 crypto::ScopedPCCERT_CONTEXT scoped_cert(cert);
286
287 // Add dummy private key data to the certificate - otherwise the certificate
288 // would be discarded by the filtering routines.
289 CRYPT_KEY_PROV_INFO private_key_data;
290 memset(&private_key_data, 0, sizeof(private_key_data));
291 if (!CertSetCertificateContextProperty(cert,
292 CERT_KEY_PROV_INFO_PROP_ID,
293 0, &private_key_data)) {
294 return false;
295 }
296 }
297
298 *selected_identities = GetClientCertsImpl(test_store.get(), request);
299 return true;
300 }
301
302 } // namespace net
303