Refuse to accept certificate chains containing any RSA public key smaller

net/base/x509_certificate_mac.cc

 // Copyright (c) 2011 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/x509_certificate.h"
 
 #include <CommonCrypto/CommonDigest.h>
 #include <CoreServices/CoreServices.h>
 #include <Security/Security.h>
 #include <time.h>
@@ skipping 715 matching lines @@
   sint32 estTime;
   CSSM_RETURN crtn = CSSM_TP_SubmitCredRequest(tp_handle, NULL,
       CSSM_TP_AUTHORITY_REQUEST_CERTISSUE, &reqSet, &callerAuthContext,
        &estTime, &refId);
   if (crtn) {
     DLOG(ERROR) << "CSSM_TP_SubmitCredRequest failed " << crtn;
     return NULL;
   }
 
   CSSM_BOOL confirmRequired;
-  CSSM_TP_RESULT_SET *resultSet = NULL;
+  CSSM_TP_RESULT_SET* resultSet = NULL;
   crtn = CSSM_TP_RetrieveCredResult(tp_handle, &refId, NULL, &estTime,
                                     &confirmRequired, &resultSet);
   ScopedEncodedCertResults scopedResults(resultSet);
   crypto::CSSMFree(refId.Data);
   if (crtn) {
     DLOG(ERROR) << "CSSM_TP_RetrieveCredResult failed " << crtn;
     return NULL;
   }
 
   if (confirmRequired) {
@@ skipping 683 matching lines @@
                                                 Pickle* pickle) {
   CSSM_DATA cert_data;
   OSStatus status = SecCertificateGetData(cert_handle, &cert_data);
   if (status)
     return false;
 
   return pickle->WriteData(reinterpret_cast<char*>(cert_data.Data),
                            cert_data.Length);
 }
 
+// static
+void X509Certificate::GetPublicKeyInfo(OSCertHandle cert_handle,
+                                       size_t* size_bits,
+                                       PublicKeyType* type) {
+  SecKeyRef key;
+  OSStatus status = SecCertificateCopyPublicKey(cert_handle, &key);
+  if (status) {
+    CFRelease(key);
+    NOTREACHED() << "SecCertificateCopyPublicKey failed: " << status;
+    return;
+  }
+
+  CSSM_KEY* cssm_key;
+  status = SecKeyGetCSSMKey(key, &cssm_key);
+  if (status) {
+    CFRelease(key);
+    NOTREACHED() << "SecKeyGetCSSMKey failed: " << status;
+    return;
+  }
+
+  *size_bits = cssm_key->Header.LogicalKeySizeInBits;
+
+  switch (cssm_key->KeyHeader.AlgorithmId) {
+    case CSSM_ALGID_RSA:
+      *type = kPublicKeyTypeRSA;
+      break;
+    case CSSM_ALGID_DSA:
+      *type = kPublicKeyTypeDSA;
+      break;
+    case CSSM_ALGID_ECDSA:
+      *type = kPublicKeyTypeECDSA;
+      break;
+    case CSSM_ALGID_DH:
+      *type = kPublicKeyTypeDH;
+      break;
+    default:
+      *type = kPublicKeyTypeUnknown;
+  }
+
+  CFRelease(key);
+}
+
 }  // namespace net