net/ssl/client_cert_store_impl_mac.cc

   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/ssl/client_cert_store_impl.h"
   6
   7 #include <CommonCrypto/CommonDigest.h>
   8 #include <CoreFoundation/CFArray.h>
   9 #include <CoreServices/CoreServices.h>
  10 #include <Security/SecBase.h>
  11 #include <Security/Security.h>
  12
  13 #include <algorithm>
  14 #include <string>
  15
  16 #include "base/callback.h"
  17 #include "base/logging.h"
  18 #include "base/mac/mac_logging.h"
  19 #include "base/mac/scoped_cftyperef.h"
  20 #include "base/strings/sys_string_conversions.h"
  21 #include "base/synchronization/lock.h"
  22 #include "crypto/mac_security_services_lock.h"
  23 #include "net/base/host_port_pair.h"
  24 #include "net/cert/x509_util.h"
  25 #include "net/cert/x509_util_mac.h"
  26
  27 using base::ScopedCFTypeRef;
  28
  29 namespace net {
  30
  31 namespace {
  32
  33 // Gets the issuer for a given cert, starting with the cert itself and
  34 // including the intermediate and finally root certificates (if any).
  35 // This function calls SecTrust but doesn't actually pay attention to the trust
  36 // result: it shouldn't be used to determine trust, just to traverse the chain.
  37 // Caller is responsible for releasing the value stored into *out_cert_chain.
  38 OSStatus CopyCertChain(SecCertificateRef cert_handle,
  39                        CFArrayRef* out_cert_chain) {
  40   DCHECK(cert_handle);
  41   DCHECK(out_cert_chain);
  42
  43   // Create an SSL policy ref configured for client cert evaluation.
  44   SecPolicyRef ssl_policy;
  45   OSStatus result = x509_util::CreateSSLClientPolicy(&ssl_policy);
  46   if (result)
  47     return result;
  48   ScopedCFTypeRef<SecPolicyRef> scoped_ssl_policy(ssl_policy);
  49
  50   // Create a SecTrustRef.
  51   ScopedCFTypeRef<CFArrayRef> input_certs(CFArrayCreate(
  52       NULL, const_cast<const void**>(reinterpret_cast<void**>(&cert_handle)),
  53       1, &kCFTypeArrayCallBacks));
  54   SecTrustRef trust_ref = NULL;
  55   {
  56     base::AutoLock lock(crypto::GetMacSecurityServicesLock());
  57     result = SecTrustCreateWithCertificates(input_certs, ssl_policy,
  58                                             &trust_ref);
  59   }
  60   if (result)
  61     return result;
  62   ScopedCFTypeRef<SecTrustRef> trust(trust_ref);
  63
  64   // Evaluate trust, which creates the cert chain.
  65   SecTrustResultType status;
  66   CSSM_TP_APPLE_EVIDENCE_INFO* status_chain;
  67   {
  68     base::AutoLock lock(crypto::GetMacSecurityServicesLock());
  69     result = SecTrustEvaluate(trust, &status);
  70   }
  71   if (result)
  72     return result;
  73   {
  74     base::AutoLock lock(crypto::GetMacSecurityServicesLock());
  75     result = SecTrustGetResult(trust, &status, out_cert_chain, &status_chain);
  76   }
  77   return result;
  78 }
  79
  80 // Returns true if |*cert| is issued by an authority in |valid_issuers|
  81 // according to Keychain Services, rather than using |cert|'s intermediate
  82 // certificates. If it is, |*cert| is updated to point to the completed
  83 // certificate
  84 bool IsIssuedByInKeychain(const std::vector<std::string>& valid_issuers,
  85                           scoped_refptr<X509Certificate>* cert) {
  86   DCHECK(cert);
  87   DCHECK(cert->get());
  88
  89   X509Certificate::OSCertHandle cert_handle = (*cert)->os_cert_handle();
  90   CFArrayRef cert_chain = NULL;
  91   OSStatus result = CopyCertChain(cert_handle, &cert_chain);
  92   if (result) {
  93     OSSTATUS_LOG(ERROR, result) << "CopyCertChain error";
  94     return false;
  95   }
  96
  97   if (!cert_chain)
  98     return false;
  99
 100   X509Certificate::OSCertHandles intermediates;
 101   for (CFIndex i = 1, chain_count = CFArrayGetCount(cert_chain);
 102        i < chain_count; ++i) {
 103     SecCertificateRef cert = reinterpret_cast<SecCertificateRef>(
 104         const_cast<void*>(CFArrayGetValueAtIndex(cert_chain, i)));
 105     intermediates.push_back(cert);
 106   }
 107
 108   scoped_refptr<X509Certificate> new_cert(X509Certificate::CreateFromHandle(
 109       cert_handle, intermediates));
 110   CFRelease(cert_chain);  // Also frees |intermediates|.
 111
 112   if (!new_cert->IsIssuedByEncoded(valid_issuers))
 113     return false;
 114
 115   cert->swap(new_cert);
 116   return true;
 117 }
 118
 119 // Examines the certificates in |preferred_cert| and |regular_certs| to find
 120 // all certificates that match the client certificate request in |request|,
 121 // storing the matching certificates in |selected_certs|.
 122 // If |query_keychain| is true, Keychain Services will be queried to construct
 123 // full certificate chains. If it is false, only the the certificates and their
 124 // intermediates (available via X509Certificate::GetIntermediateCertificates())
 125 // will be considered.
 126 void GetClientCertsImpl(const scoped_refptr<X509Certificate>& preferred_cert,
 127                         const CertificateList& regular_certs,
 128                         const SSLCertRequestInfo& request,
 129                         bool query_keychain,
 130                         CertificateList* selected_certs) {
 131   CertificateList preliminary_list;
 132   if (preferred_cert.get())
 133     preliminary_list.push_back(preferred_cert);
 134   preliminary_list.insert(preliminary_list.end(), regular_certs.begin(),
 135                           regular_certs.end());
 136
 137   selected_certs->clear();
 138   for (size_t i = 0; i < preliminary_list.size(); ++i) {
 139     scoped_refptr<X509Certificate>& cert = preliminary_list[i];
 140     if (cert->HasExpired() || !cert->SupportsSSLClientAuth())
 141       continue;
 142
 143     // Skip duplicates (a cert may be in multiple keychains).
 144     const SHA1HashValue& fingerprint = cert->fingerprint();
 145     size_t pos;
 146     for (pos = 0; pos < selected_certs->size(); ++pos) {
 147       if ((*selected_certs)[pos]->fingerprint().Equals(fingerprint))
 148         break;
 149     }
 150     if (pos < selected_certs->size())
 151       continue;
 152
 153     // Check if the certificate issuer is allowed by the server.
 154     if (request.cert_authorities.empty() ||
 155         cert->IsIssuedByEncoded(request.cert_authorities) ||
 156         (query_keychain &&
 157          IsIssuedByInKeychain(request.cert_authorities, &cert))) {
 158       selected_certs->push_back(cert);
 159     }
 160   }
 161
 162   // Preferred cert should appear first in the ui, so exclude it from the
 163   // sorting.
 164   CertificateList::iterator sort_begin = selected_certs->begin();
 165   CertificateList::iterator sort_end = selected_certs->end();
 166   if (preferred_cert.get() && sort_begin != sort_end &&
 167       sort_begin->get() == preferred_cert.get()) {
 168     ++sort_begin;
 169   }
 170   sort(sort_begin, sort_end, x509_util::ClientCertSorter());
 171 }
 172
 173 }  // namespace
 174
 175 ClientCertStoreImpl::ClientCertStoreImpl() {}
 176
 177 ClientCertStoreImpl::~ClientCertStoreImpl() {}
 178
 179 void ClientCertStoreImpl::GetClientCerts(const SSLCertRequestInfo& request,
 180                                          CertificateList* selected_certs,
 181                                          const base::Closure& callback) {
 182   std::string server_domain =
 183       HostPortPair::FromString(request.host_and_port).host();
 184
 185   ScopedCFTypeRef<SecIdentityRef> preferred_identity;
 186   if (!server_domain.empty()) {
 187     // See if there's an identity preference for this domain:
 188     ScopedCFTypeRef<CFStringRef> domain_str(
 189         base::SysUTF8ToCFStringRef("https://" + server_domain));
 190     SecIdentityRef identity = NULL;
 191     // While SecIdentityCopyPreferences appears to take a list of CA issuers
 192     // to restrict the identity search to, within Security.framework the
 193     // argument is ignored and filtering unimplemented. See
 194     // SecIdentity.cpp in libsecurity_keychain, specifically
 195     // _SecIdentityCopyPreferenceMatchingName().
 196     {
 197       base::AutoLock lock(crypto::GetMacSecurityServicesLock());
 198       if (SecIdentityCopyPreference(domain_str, 0, NULL, &identity) == noErr)
 199         preferred_identity.reset(identity);
 200     }
 201   }
 202
 203   // Now enumerate the identities in the available keychains.
 204   scoped_refptr<X509Certificate> preferred_cert = NULL;
 205   CertificateList regular_certs;
 206
 207   SecIdentitySearchRef search = NULL;
 208   OSStatus err;
 209   {
 210     base::AutoLock lock(crypto::GetMacSecurityServicesLock());
 211     err = SecIdentitySearchCreate(NULL, CSSM_KEYUSE_SIGN, &search);
 212   }
 213   if (err) {
 214     selected_certs->clear();
 215     callback.Run();
 216     return;
 217   }
 218   ScopedCFTypeRef<SecIdentitySearchRef> scoped_search(search);
 219   while (!err) {
 220     SecIdentityRef identity = NULL;
 221     {
 222       base::AutoLock lock(crypto::GetMacSecurityServicesLock());
 223       err = SecIdentitySearchCopyNext(search, &identity);
 224     }
 225     if (err)
 226       break;
 227     ScopedCFTypeRef<SecIdentityRef> scoped_identity(identity);
 228
 229     SecCertificateRef cert_handle;
 230     err = SecIdentityCopyCertificate(identity, &cert_handle);
 231     if (err != noErr)
 232       continue;
 233     ScopedCFTypeRef<SecCertificateRef> scoped_cert_handle(cert_handle);
 234
 235     scoped_refptr<X509Certificate> cert(
 236         X509Certificate::CreateFromHandle(cert_handle,
 237                                           X509Certificate::OSCertHandles()));
 238
 239     if (preferred_identity && CFEqual(preferred_identity, identity)) {
 240       // Only one certificate should match.
 241       DCHECK(!preferred_cert.get());
 242       preferred_cert = cert;
 243     } else {
 244       regular_certs.push_back(cert);
 245     }
 246   }
 247
 248   if (err != errSecItemNotFound) {
 249     OSSTATUS_LOG(ERROR, err) << "SecIdentitySearch error";
 250     selected_certs->clear();
 251     callback.Run();
 252     return;
 253   }
 254
 255   GetClientCertsImpl(preferred_cert, regular_certs, request, true,
 256                      selected_certs);
 257   callback.Run();
 258 }
 259
 260 bool ClientCertStoreImpl::SelectClientCertsForTesting(
 261     const CertificateList& input_certs,
 262     const SSLCertRequestInfo& request,
 263     CertificateList* selected_certs) {
 264   GetClientCertsImpl(NULL, input_certs, request, false, selected_certs);
 265   return true;
 266 }
 267
 268 #if !defined(OS_IOS)
 269 bool ClientCertStoreImpl::SelectClientCertsGivenPreferredForTesting(
 270     const scoped_refptr<X509Certificate>& preferred_cert,
 271     const CertificateList& regular_certs,
 272     const SSLCertRequestInfo& request,
 273     CertificateList* selected_certs) {
 274   GetClientCertsImpl(
 275       preferred_cert, regular_certs, request, false, selected_certs);
 276   return true;
 277 }
 278 #endif
 279
 280 }  // namespace net