net/ssl/client_cert_store_win.cc

   1 // Copyright 2013 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/ssl/client_cert_store_win.h"
   6
   7 #include <algorithm>
   8 #include <string>
   9
  10 #define SECURITY_WIN32  // Needs to be defined before including security.h
  11 #include <windows.h>
  12 #include <wincrypt.h>
  13 #include <security.h>
  14
  15 #include "base/callback.h"
  16 #include "base/logging.h"
  17 #include "crypto/scoped_capi_types.h"
  18 #include "net/cert/x509_util.h"
  19
  20 namespace net {
  21
  22 namespace {
  23
  24 // Callback required by Windows API function CertFindChainInStore(). In addition
  25 // to filtering by extended/enhanced key usage, we do not show expired
  26 // certificates and require digital signature usage in the key usage extension.
  27 //
  28 // This matches our behavior on Mac OS X and that of NSS. It also matches the
  29 // default behavior of IE8. See http://support.microsoft.com/kb/890326 and
  30 // http://blogs.msdn.com/b/askie/archive/2009/06/09/my-expired-client-certifica
  31 //     tes-no-longer-display-when-connecting-to-my-web-server-using-ie8.aspx
  32 static BOOL WINAPI ClientCertFindCallback(PCCERT_CONTEXT cert_context,
  33                                           void* find_arg) {
  34   // Verify the certificate key usage is appropriate or not specified.
  35   BYTE key_usage;
  36   if (CertGetIntendedKeyUsage(X509_ASN_ENCODING, cert_context->pCertInfo,
  37                               &key_usage, 1)) {
  38     if (!(key_usage & CERT_DIGITAL_SIGNATURE_KEY_USAGE))
  39       return FALSE;
  40   } else {
  41     DWORD err = GetLastError();
  42     // If |err| is non-zero, it's an actual error. Otherwise the extension
  43     // just isn't present, and we treat it as if everything was allowed.
  44     if (err) {
  45       DLOG(ERROR) << "CertGetIntendedKeyUsage failed: " << err;
  46       return FALSE;
  47     }
  48   }
  49
  50   // Verify the current time is within the certificate's validity period.
  51   if (CertVerifyTimeValidity(NULL, cert_context->pCertInfo) != 0)
  52     return FALSE;
  53
  54   // Verify private key metadata is associated with this certificate.
  55   // TODO(ppi): Is this really needed? Isn't it equivalent to leaving
  56   // CERT_CHAIN_FIND_BY_ISSUER_NO_KEY_FLAG not set in |find_flags| argument of
  57   // CertFindChainInStore()?
  58   DWORD size = 0;
  59   if (!CertGetCertificateContextProperty(
  60           cert_context, CERT_KEY_PROV_INFO_PROP_ID, NULL, &size)) {
  61     return FALSE;
  62   }
  63
  64   return TRUE;
  65 }
  66
  67 void GetClientCertsImpl(HCERTSTORE cert_store,
  68                         const SSLCertRequestInfo& request,
  69                         CertificateList* selected_certs) {
  70   selected_certs->clear();
  71
  72   const size_t auth_count = request.cert_authorities.size();
  73   std::vector<CERT_NAME_BLOB> issuers(auth_count);
  74   for (size_t i = 0; i < auth_count; ++i) {
  75     issuers[i].cbData = static_cast<DWORD>(request.cert_authorities[i].size());
  76     issuers[i].pbData = reinterpret_cast<BYTE*>(
  77         const_cast<char*>(request.cert_authorities[i].data()));
  78   }
  79
  80   // Enumerate the client certificates.
  81   CERT_CHAIN_FIND_BY_ISSUER_PARA find_by_issuer_para;
  82   memset(&find_by_issuer_para, 0, sizeof(find_by_issuer_para));
  83   find_by_issuer_para.cbSize = sizeof(find_by_issuer_para);
  84   find_by_issuer_para.pszUsageIdentifier = szOID_PKIX_KP_CLIENT_AUTH;
  85   find_by_issuer_para.cIssuer = static_cast<DWORD>(auth_count);
  86   find_by_issuer_para.rgIssuer =
  87       reinterpret_cast<CERT_NAME_BLOB*>(issuers.data());
  88   find_by_issuer_para.pfnFindCallback = ClientCertFindCallback;
  89
  90   PCCERT_CHAIN_CONTEXT chain_context = NULL;
  91   DWORD find_flags = CERT_CHAIN_FIND_BY_ISSUER_CACHE_ONLY_FLAG |
  92                      CERT_CHAIN_FIND_BY_ISSUER_CACHE_ONLY_URL_FLAG;
  93   for (;;) {
  94     // Find a certificate chain.
  95     chain_context = CertFindChainInStore(cert_store,
  96                                          X509_ASN_ENCODING,
  97                                          find_flags,
  98                                          CERT_CHAIN_FIND_BY_ISSUER,
  99                                          &find_by_issuer_para,
 100                                          chain_context);
 101     if (!chain_context) {
 102       if (GetLastError() != CRYPT_E_NOT_FOUND)
 103         DPLOG(ERROR) << "CertFindChainInStore failed: ";
 104       break;
 105     }
 106
 107     // Get the leaf certificate.
 108     PCCERT_CONTEXT cert_context =
 109         chain_context->rgpChain[0]->rgpElement[0]->pCertContext;
 110     // Copy the certificate, so that it is valid after |cert_store| is closed.
 111     PCCERT_CONTEXT cert_context2 = NULL;
 112     BOOL ok = CertAddCertificateContextToStore(NULL, cert_context,
 113                                                CERT_STORE_ADD_USE_EXISTING,
 114                                                &cert_context2);
 115     if (!ok) {
 116       NOTREACHED();
 117       continue;
 118     }
 119
 120     // Grab the intermediates, if any.
 121     X509Certificate::OSCertHandles intermediates;
 122     for (DWORD i = 1; i < chain_context->rgpChain[0]->cElement; ++i) {
 123       PCCERT_CONTEXT chain_intermediate =
 124           chain_context->rgpChain[0]->rgpElement[i]->pCertContext;
 125       PCCERT_CONTEXT copied_intermediate = NULL;
 126       ok = CertAddCertificateContextToStore(NULL, chain_intermediate,
 127                                             CERT_STORE_ADD_USE_EXISTING,
 128                                             &copied_intermediate);
 129       if (ok)
 130         intermediates.push_back(copied_intermediate);
 131     }
 132     scoped_refptr<X509Certificate> cert = X509Certificate::CreateFromHandle(
 133         cert_context2, intermediates);
 134     selected_certs->push_back(cert);
 135     CertFreeCertificateContext(cert_context2);
 136     for (size_t i = 0; i < intermediates.size(); ++i)
 137       CertFreeCertificateContext(intermediates[i]);
 138   }
 139
 140   std::sort(selected_certs->begin(), selected_certs->end(),
 141             x509_util::ClientCertSorter());
 142 }
 143
 144 }  // namespace
 145
 146 ClientCertStoreWin::ClientCertStoreWin() {}
 147
 148 ClientCertStoreWin::~ClientCertStoreWin() {}
 149
 150 void ClientCertStoreWin::GetClientCerts(const SSLCertRequestInfo& request,
 151                                          CertificateList* selected_certs,
 152                                          const base::Closure& callback) {
 153   // Client certificates of the user are in the "MY" system certificate store.
 154   HCERTSTORE my_cert_store = CertOpenSystemStore(NULL, L"MY");
 155   if (!my_cert_store) {
 156     PLOG(ERROR) << "Could not open the \"MY\" system certificate store: ";
 157     selected_certs->clear();
 158     callback.Run();
 159     return;
 160   }
 161
 162   GetClientCertsImpl(my_cert_store, request, selected_certs);
 163   if (!CertCloseStore(my_cert_store, CERT_CLOSE_STORE_CHECK_FLAG))
 164     PLOG(ERROR) << "Could not close the \"MY\" system certificate store: ";
 165   callback.Run();
 166 }
 167
 168 bool ClientCertStoreWin::SelectClientCertsForTesting(
 169     const CertificateList& input_certs,
 170     const SSLCertRequestInfo& request,
 171     CertificateList* selected_certs) {
 172   typedef crypto::ScopedCAPIHandle<
 173       HCERTSTORE,
 174       crypto::CAPIDestroyerWithFlags<HCERTSTORE,
 175                                      CertCloseStore, 0> > ScopedHCERTSTORE;
 176
 177   ScopedHCERTSTORE test_store(CertOpenStore(CERT_STORE_PROV_MEMORY, 0, NULL, 0,
 178                                             NULL));
 179   if (!test_store)
 180     return false;
 181
 182   // Add available certificates to the test store.
 183   for (size_t i = 0; i < input_certs.size(); ++i) {
 184     // Add the certificate to the test store.
 185     PCCERT_CONTEXT cert = NULL;
 186     if (!CertAddCertificateContextToStore(test_store,
 187                                           input_certs[i]->os_cert_handle(),
 188                                           CERT_STORE_ADD_NEW, &cert)) {
 189       return false;
 190     }
 191     // Add dummy private key data to the certificate - otherwise the certificate
 192     // would be discarded by the filtering routines.
 193     CRYPT_KEY_PROV_INFO private_key_data;
 194     memset(&private_key_data, 0, sizeof(private_key_data));
 195     if (!CertSetCertificateContextProperty(cert,
 196                                            CERT_KEY_PROV_INFO_PROP_ID,
 197                                            0, &private_key_data)) {
 198       return false;
 199     }
 200     // Decrement the reference count of the certificate (since we requested a
 201     // copy).
 202     if (!CertFreeCertificateContext(cert))
 203       return false;
 204   }
 205
 206   GetClientCertsImpl(test_store.get(), request, selected_certs);
 207   return true;
 208 }
 209
 210 }  // namespace net