Add support for MD2, MD4, and MD5 to SignatureAlgorithm.

net/cert/x509_util_openssl.cc

 // Copyright (c) 2012 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/cert/x509_util_openssl.h"
 
 #include <limits.h>
 
 #include <algorithm>
 #include <memory>
@@ skipping 321 matching lines @@
                         &signature_value, nullptr))
     return false;
 
   std::unique_ptr<SignatureAlgorithm> signature_algorithm =
       SignatureAlgorithm::Create(signature_algorithm_tlv, nullptr);
   if (!signature_algorithm)
     return false;
 
   const EVP_MD* digest_evp_md = nullptr;
   switch (signature_algorithm->digest()) {
+    case net::DigestAlgorithm::Md2:
+    case net::DigestAlgorithm::Md4:
+      // Shouldn't be reachable.
+      digest_evp_md = nullptr;
+      break;
+
+    // Per RFC 5929 section 4.1, MD5 and SHA1 map to SHA256.
+    case net::DigestAlgorithm::Md5:
     case net::DigestAlgorithm::Sha1:
     case net::DigestAlgorithm::Sha256:
       digest_evp_md = EVP_sha256();
       break;
 
     case net::DigestAlgorithm::Sha384:
       digest_evp_md = EVP_sha384();
       break;
 
     case net::DigestAlgorithm::Sha512:
@@ skipping 29 matching lines @@
 bssl::UniquePtr<CRYPTO_BUFFER> CreateCryptoBuffer(
     const base::StringPiece& data) {
   return bssl::UniquePtr<CRYPTO_BUFFER>(
       CRYPTO_BUFFER_new(reinterpret_cast<const uint8_t*>(data.data()),
                         data.size(), GetBufferPool()));
 }
 
 }  // namespace x509_util
 
 }  // namespace net