Refuse to accept certificate chains containing any RSA public key smaller

net/base/x509_certificate_nss.cc

Index: net/base/x509_certificate_nss.cc
===================================================================
--- net/base/x509_certificate_nss.cc	(revision 110129)
+++ net/base/x509_certificate_nss.cc	(working copy)
@@ -1045,4 +1045,29 @@
       cert_handle->derCert.len);
 }
 
+//static
+void X509Certificate::GetPublicKeyInfo(OSCertHandle cert_handle,
+                                       size_t* size_bits,
+                                       PublicKeyType* type) {
+  SECKEYPublicKey* key = CERT_ExtractPublicKey(cert_handle);
+  *size_bits = SECKEY_PublicKeyStrengthInBits(key);
+
+  switch (key->keyType) {
+    case rsaKey:
+      *type = PublicKeyType::RSA;
+      break;
+    case dsaKey:
+      *type = PublicKeyType::DSA;
+      break;
+    case dhKey:
+      *type = PublicKeyType::DH;
+      break;
+    case ecKey:
+      *type = PublicKeyType::ECDSA;
+      break;
+    default:
+      *type = PublicKeyType::NONE;
+  }
+}
+
 }  // namespace net