Bring back SCT_STATUS_INVALID for cached entries

https://codereview.chromium.org/2241213002/ split SCT_STATUS_INVALID
into two new enum values to record the different reasons that an SCT
might be invalid. However, we didn't realize that SCT_STATUS_INVALID
might still be present in disk cache entries, resulting in renderer
kills when the browser tries to deserialize SSLStatus objects containing
these cached SCT_STATUS_INVALID values.

This CL brings back SCT_STATUS_INVALID and documents it as deprecated,
but still existent for the sake of cache entries.

BUG=640296

Review-Url: https://codereview.chromium.org/2277653002
Cr-Commit-Position: refs/heads/master@{#414280}

chrome/browser/ssl/chrome_expect_ct_reporter.cc

@@ -152,6 +152,7 @@ void ChromeExpectCTReporter::OnExpectCTFailed(
       case net::ct::SCT_STATUS_LOG_UNKNOWN:
         AddUnknownSCT(sct_and_status, unknown_scts.get());
         break;
+      case net::ct::SCT_STATUS_INVALID:
       case net::ct::SCT_STATUS_INVALID_SIGNATURE:
       case net::ct::SCT_STATUS_INVALID_TIMESTAMP:
         AddInvalidSCT(sct_and_status, invalid_scts.get());

chrome/browser/ui/website_settings/website_settings.cc

@@ -197,7 +197,9 @@ int GetSiteIdentityDetailsMessageByCTInfo(
                   : IDS_PAGE_INFO_SECURITY_TAB_SECURE_IDENTITY_CT_VERIFIED);
 
   // Any invalid SCT.
-  if (CertificateTransparencyStatusMatchAny(
+  if (CertificateTransparencyStatusMatchAny(sct_verify_statuses,
+                                            net::ct::SCT_STATUS_INVALID) ||
+      CertificateTransparencyStatusMatchAny(
           sct_verify_statuses, net::ct::SCT_STATUS_INVALID_TIMESTAMP) ||
       CertificateTransparencyStatusMatchAny(
           sct_verify_statuses, net::ct::SCT_STATUS_INVALID_SIGNATURE))

content/common/ssl_status_serialization.cc

@@ -31,6 +31,9 @@ bool CheckSecurityStyle(int security_style) {
 bool CheckSCTStatus(uint32_t sct_status) {
   switch (sct_status) {
     case net::ct::SCT_STATUS_LOG_UNKNOWN:
+    // INVALID is deprecated and should not be used anymore, but it
+    // might have been previously written into the disk cache.
+    case net::ct::SCT_STATUS_INVALID:
     case net::ct::SCT_STATUS_INVALID_SIGNATURE:
     case net::ct::SCT_STATUS_OK:
     case net::ct::SCT_STATUS_INVALID_TIMESTAMP:

content/common/ssl_status_serialization_unittest.cc

@@ -148,4 +148,19 @@ TEST(SSLStatusSerializationTest, DeserializeBogusSCTVerifyStatus) {
   EXPECT_PRED2(SSLStatusAreEqual, SSLStatus(), deserialized);
 }
 
+// Test that SCTVerifyStatus INVALID can be deserialized; even though
+// this value is deprecated, it may still appear in previously written
+// disk cache entries. Regression test for https://crbug.com/640296
+TEST(SSLStatusSerializationTest, DeserializeInvalidSCT) {
+  SSLStatus status;
+  SetTestStatus(&status);
+  status.sct_statuses.push_back(
+      static_cast<net::ct::SCTVerifyStatus>(net::ct::SCT_STATUS_INVALID));
+  std::string serialized = SerializeSecurityInfo(status);
+
+  SSLStatus deserialized;
+  ASSERT_TRUE(DeserializeSecurityInfo(serialized, &deserialized));
+  EXPECT_PRED2(SSLStatusAreEqual, status, deserialized);
+}
+
 }  // namespace

net/cert/ct_sct_to_string.cc

@@ -62,6 +62,8 @@ const std::string StatusToString(SCTVerifyStatus status) {
   switch (status) {
     case SCT_STATUS_LOG_UNKNOWN:
       return "From unknown log";
+    case SCT_STATUS_INVALID:
+      return "Invalid";
     case SCT_STATUS_INVALID_SIGNATURE:
       return "Invalid signature";
     case SCT_STATUS_OK:

net/cert/sct_status_flags.h

@@ -21,9 +21,12 @@ enum SCTVerifyStatus {
   // The SCT is from an unknown log, so we cannot verify its signature.
   SCT_STATUS_LOG_UNKNOWN = 1,
 
-  // SCTVerifyStatus=2 used to represent SCT_STATUS_INVALID, which has now been
-  // split into INVALID_SIGNATURE and INVALID_TIMESTAMP to represent the
-  // different reasons an SCT could be invalid.
+  // This value is deprecated and should not be used. It has been split
+  // into INVALID_SIGNATURE and INVALID_TIMESTAMP to represent the
+  // different reasons an SCT could be invalid. Though it is no longer
+  // in use, it is preserved here because it may be present in
+  // serialized messages.
+  SCT_STATUS_INVALID = 2,
 
   // The SCT is from a known log, and the signature is valid.
   SCT_STATUS_OK = 3,