Refuse to accept certificate chains containing any RSA public key smaller

net/base/x509_certificate_openssl.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 <openssl/asn1.h>
 #include <openssl/crypto.h>
 #include <openssl/obj_mac.h>
 #include <openssl/pem.h>
@@ skipping 601 matching lines @@
                                                 Pickle* pickle) {
   DERCache der_cache;
   if (!GetDERAndCacheIfNeeded(cert_handle, &der_cache))
     return false;
 
   return pickle->WriteData(
       reinterpret_cast<const char*>(der_cache.data),
       der_cache.data_length);
 }
 
+//static
+void X509Certificate::GetPublicKeyInfo(OSCertHandle cert_handle,
+                                       size_t* size_bits,
+                                       PublicKeyType* type) {
+  EVP_PKEY* key = X509_get_pubkey(cert_handle);
+  *size_bits = EVP_PKEY_size(key) * 8;
+
+  switch (key->type) {
+    case EVP_PKEY_RSA:
+      *type = PublicKeyType::RSA;
+      break;
+    case EVP_PKEY_DSA:
+      *type = PublicKeyType::DSA;
+      break;
+    case EVP_PKEY_EC:
+      *type = PublicKeyType::EC;
+      break;
+    case EVP_PKEY_DH:
+      *type = PublicKeyType::DH;
+      break;
+    default:
+      *type = PublicKeyType::NONE;
+  }
+}
+
 }  // namespace net