Implement LoadTemporaryRoot for Windows

net/base/test_root_certs_win.cc

+// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "net/base/test_root_certs.h"
+
+#include <windows.h>
+#include <wincrypt.h>
+
+#include "base/basictypes.h"
+#include "base/lazy_instance.h"
+#include "base/logging.h"
+#include "net/base/x509_certificate.h"
+
+namespace net {
+
+namespace {
+
+// Provides a CertDllOpenStoreProv callback provider function, to be called
+// by CertOpenStore when the CERT_STORE_PROV_SYSTEM_W store is opened. See
+// http://msdn.microsoft.com/en-us/library/aa376043(VS.85).aspx.
+BOOL WINAPI InterceptedOpenStoreW(LPCSTR store_provider,
+                                  DWORD encoding,
+                                  HCRYPTPROV crypt_provider,
+                                  DWORD flags,
+                                  const void* extra,
+                                  HCERTSTORE memory_store,
+                                  PCERT_STORE_PROV_INFO store_info);
+
+// CryptoAPIInjector is used to inject a store provider function for system
+// certificate stores before the one provided internally by Crypt32.dll.
+// Once injected, there is no way to remove, so every call to open a system
+// store will be redirected to the injected function.
+struct CryptoAPIInjector {
+  // The previous default function for opening system stores. For most
+  // configurations, this should point to Crypt32's internal
+  // I_CertDllOpenSystemStoreProvW function.
+  PFN_CERT_DLL_OPEN_STORE_PROV_FUNC original_function;
+
+  // The handle that CryptoAPI uses to ensure the DLL implementing
+  // |original_function| remains loaded in memory.
+  HCRYPTOIDFUNCADDR original_handle;
+
+ private:
+  friend struct base::DefaultLazyInstanceTraits<CryptoAPIInjector>;
+
+  CryptoAPIInjector()
+      : original_function(NULL),
+        original_handle(NULL) {
+    HCRYPTOIDFUNCSET registered_functions =
+        CryptInitOIDFunctionSet(CRYPT_OID_OPEN_STORE_PROV_FUNC, 0);
+
+    // Preserve the original handler function in |original_function|. If other
+    // functions are overridden, they will also need to be preserved.
+    BOOL ok = CryptGetOIDFunctionAddress(
+        registered_functions, 0, CERT_STORE_PROV_SYSTEM_W, 0,
+        reinterpret_cast<void**>(&original_function), &original_handle);
+    DCHECK(ok);
+
+    // For now, intercept only the numeric form of the system store
+    // function, CERT_STORE_PROV_SYSTEM_W (0x0A), which is what Crypt32
+    // functionality uses exclusively. Depending on the machine that tests
+    // are being run on, it may prove necessary to also intercept
+    // sz_CERT_STORE_PROV_SYSTEM_[A/W] and CERT_STORE_PROV_SYSTEM_A, based
+    // on whether or not any third-party CryptoAPI modules have been
+    // installed.
+    const CRYPT_OID_FUNC_ENTRY kFunctionToIntercept =
+        { CERT_STORE_PROV_SYSTEM_W, &InterceptedOpenStoreW };
+
+    // Inject kFunctionToIntercept at the front of the linked list that
+    // crypt32 uses when CertOpenStore is called, replacing the existing
+    // registered function.
+    ok = CryptInstallOIDFunctionAddress(NULL, 0,
+                                        CRYPT_OID_OPEN_STORE_PROV_FUNC, 1,
+                                        &kFunctionToIntercept,
+                                        CRYPT_INSTALL_OID_FUNC_BEFORE_FLAG);
+    DCHECK(ok);
+  }
+
+  // This is never called, because this object is intentionally leaked.
+  // Certificate verification happens on a non-joinable worker thread, which
+  // may still be running when ~AtExitManager is called, so the LazyInstance
+  // must be leaky.
+  ~CryptoAPIInjector() {
+    original_function = NULL;
+    CryptFreeOIDFunctionAddress(original_handle, NULL);
+  }
+};
+
+base::LazyInstance<CryptoAPIInjector,
+                   base::LeakyLazyInstanceTraits<CryptoAPIInjector> >
+    g_capi_injector(base::LINKER_INITIALIZED);
+
+BOOL WINAPI InterceptedOpenStoreW(LPCSTR store_provider,
+                                  DWORD encoding,
+                                  HCRYPTPROV crypt_provider,
+                                  DWORD flags,
+                                  const void* store_name,
+                                  HCERTSTORE memory_store,
+                                  PCERT_STORE_PROV_INFO store_info) {
+  // If the high word is all zeroes, then |store_provider| is a numeric ID.
+  // Otherwise, it's a pointer to a null-terminated ASCII string. See the
+  // documentation for CryptGetOIDFunctionAddress for more information.
+  uint32 store_as_uint = reinterpret_cast<uint32>(store_provider);
+  if (store_as_uint > 0xFFFF || store_provider != CERT_STORE_PROV_SYSTEM_W ||
+      !g_capi_injector.Get().original_function)
+    return FALSE;
+
+  BOOL ok = g_capi_injector.Get().original_function(store_provider, encoding,
+                                                    crypt_provider, flags,
+                                                    store_name, memory_store,
+                                                    store_info);
+  // Only the Root store should have certificates injected. If
+  // CERT_SYSTEM_STORE_RELOCATE_FLAG is set, then |store_name| points to a
+  // CERT_SYSTEM_STORE_RELOCATE_PARA structure, rather than a
+  // NULL-terminated wide string, so check before making a string
+  // comparison.
+  if (!ok || TestRootCerts::GetInstance()->IsEmpty() ||
+      (flags & CERT_SYSTEM_STORE_RELOCATE_FLAG) ||
+      lstrcmpiW(reinterpret_cast<LPCWSTR>(store_name), L"root"))
+    return ok;
+
+  // The result of CertOpenStore with CERT_STORE_PROV_SYSTEM_W is documented
+  // to be a collection store, and that appears to hold for |memory_store|.
+  // Attempting to add an individual certificate to |memory_store| causes
+  // the request to be forwarded to the first physical store in the
+  // collection that accepts modifications, which will cause a secure
+  // confirmation dialog to be displayed, confirming the user wishes to
+  // trust the certificate. However, appending a store to the collection
+  // will merely modify the temporary collection store, and will not persist
+  // any changes to the underlying physical store. When the |memory_store| is
+  // searched to see if a certificate is in the Root store, all the
+  // underlying stores in the collection will be searched, and any certificate
+  // in temporary_roots() will be found and seen as trusted.
+  return CertAddStoreToCollection(
+      memory_store, TestRootCerts::GetInstance()->temporary_roots(), 0, 0);
+}
+
+}  // namespace
+
+bool TestRootCerts::Add(X509Certificate* certificate) {
+  // Ensure that the default CryptoAPI functionality has been intercepted.
+  // If a test certificate is never added, then no interception should
+  // happen.
+  g_capi_injector.Get();
+
+  BOOL ok = CertAddCertificateContextToStore(
+      temporary_roots_, certificate->os_cert_handle(),
+      CERT_STORE_ADD_NEW, NULL);
+  if (!ok) {
+    // If the certificate is already added, return successfully.
+    return GetLastError() == CRYPT_E_EXISTS;
+  }
+
+  empty_ = false;
+  return true;
+}
+
+void TestRootCerts::Clear() {
+  empty_ = true;
+
+  PCCERT_CONTEXT prev_cert = NULL;
+  while (prev_cert = CertEnumCertificatesInStore(temporary_roots_, NULL))
+    CertDeleteCertificateFromStore(prev_cert);
+}
+
+bool TestRootCerts::IsEmpty() const {
+  return empty_;
+}
+
+HCERTCHAINENGINE TestRootCerts::GetChainEngine() const {
+  if (IsEmpty())
+    return NULL;  // Default chain engine will suffice.
+
+  // Each HCERTCHAINENGINE caches both the configured system stores and
+  // information about each chain that has been built. In order to ensure
+  // that changes to |temporary_roots_| are properly propagated and that the
+  // various caches are flushed, when at least one certificate is added,
+  // return a new chain engine for every call. Each chain engine creation
+  // should re-open the root store, ensuring the most recent changes are
+  // visible.
+  CERT_CHAIN_ENGINE_CONFIG engine_config = {
+    sizeof(engine_config)
+  };
+  engine_config.dwFlags =
+      CERT_CHAIN_ENABLE_CACHE_AUTO_UPDATE |
+      CERT_CHAIN_ENABLE_SHARE_STORE;
+  HCERTCHAINENGINE chain_engine = NULL;
+  BOOL ok = CertCreateCertificateChainEngine(&engine_config, &chain_engine);
+  DCHECK(ok);
+  return chain_engine;
+}
+
+TestRootCerts::~TestRootCerts() {
+  CertCloseStore(temporary_roots_, 0);
+}
+
+void TestRootCerts::Init() {
+  empty_ = true;
+  temporary_roots_ = CertOpenStore(
+      CERT_STORE_PROV_MEMORY, 0, NULL,
+      CERT_STORE_DEFER_CLOSE_UNTIL_LAST_FREE_FLAG, NULL);
+  DCHECK(temporary_roots_);
+}
+
+}  // namespace net