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

net/cert/internal/signature_algorithm_unittest.cc

Index: net/cert/internal/signature_algorithm_unittest.cc
diff --git a/net/cert/internal/signature_algorithm_unittest.cc b/net/cert/internal/signature_algorithm_unittest.cc
index 2c124ada0d6e00e5c6cd331dcea626f52a815937..6e7c47318b98dca68e809e3df73a748fb97c0d73 100644
--- a/net/cert/internal/signature_algorithm_unittest.cc
+++ b/net/cert/internal/signature_algorithm_unittest.cc
@@ -1064,6 +1064,69 @@ TEST(SignatureAlgorithmTest, ParseDerRsaPssNonDefaultHashAndMaskGenAndSalt) {
   EXPECT_EQ(10u, params->salt_length());
 }
 
+// Parses a md5WithRSAEncryption which contains a NULL parameters field.
+//
+//   SEQUENCE (2 elem)
+//       OBJECT IDENTIFIER  1.2.840.113549.1.1.4
+//       NULL
+TEST(SignatureAlgorithmTest, ParseDerMd5WithRsaEncryptionNullParams) {
+  // clang-format off
+  const uint8_t kData[] = {
+      0x30, 0x0D,  // SEQUENCE (13 bytes)
+      0x06, 0x09,  // OBJECT IDENTIFIER (9 bytes)
+      0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x04,
+      0x05, 0x00,  // NULL (0 bytes)
+  };
+  // clang-format on
+  std::unique_ptr<SignatureAlgorithm> algorithm;
+  ASSERT_TRUE(ParseDer(kData, &algorithm));
+
+  EXPECT_EQ(SignatureAlgorithmId::RsaPkcs1, algorithm->algorithm());
+  EXPECT_EQ(DigestAlgorithm::Md5, algorithm->digest());
+}
+
+// Parses a md4WithRSAEncryption which contains a NULL parameters field.
+//
+//   SEQUENCE (2 elem)
+//       OBJECT IDENTIFIER  1.2.840.113549.1.1.3
+//       NULL
+TEST(SignatureAlgorithmTest, ParseDerMd4WithRsaEncryptionNullParams) {
+  // clang-format off
+  const uint8_t kData[] = {
+      0x30, 0x0D,  // SEQUENCE (13 bytes)
+      0x06, 0x09,  // OBJECT IDENTIFIER (9 bytes)
+      0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x03,
+      0x05, 0x00,  // NULL (0 bytes)
+  };
+  // clang-format on
+  std::unique_ptr<SignatureAlgorithm> algorithm;
+  ASSERT_TRUE(ParseDer(kData, &algorithm));
+
+  EXPECT_EQ(SignatureAlgorithmId::RsaPkcs1, algorithm->algorithm());
+  EXPECT_EQ(DigestAlgorithm::Md4, algorithm->digest());
+}
+
+// Parses a md2WithRSAEncryption which contains a NULL parameters field.
+//
+//   SEQUENCE (2 elem)
+//       OBJECT IDENTIFIER  1.2.840.113549.1.1.2
+//       NULL
+TEST(SignatureAlgorithmTest, ParseDerMd2WithRsaEncryptionNullParams) {
+  // clang-format off
+  const uint8_t kData[] = {
+      0x30, 0x0D,  // SEQUENCE (13 bytes)
+      0x06, 0x09,  // OBJECT IDENTIFIER (9 bytes)
+      0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x02,
+      0x05, 0x00,  // NULL (0 bytes)
+  };
+  // clang-format on
+  std::unique_ptr<SignatureAlgorithm> algorithm;
+  ASSERT_TRUE(ParseDer(kData, &algorithm));
+
+  EXPECT_EQ(SignatureAlgorithmId::RsaPkcs1, algorithm->algorithm());
+  EXPECT_EQ(DigestAlgorithm::Md2, algorithm->digest());
+}
+
 }  // namespace
 
 }  // namespace net