Merge "Reject partial clear subsamples when keys are not loaded" into rvc-dev

libwvdrmengine/cdm/src/wv_content_decryption_module.cpp

@@ -313,8 +313,6 @@ CdmResponseType WvContentDecryptionModule::DecryptV16(
     bool status =
         cdm_engine->FindSessionForKey(parameters.key_id, &local_session_id);
     if (!status) {
-      // A key does not need to be loaded if the content consists entirely of
-      // clear data.
       bool is_any_protected = std::any_of(
           std::begin(parameters.samples), std::end(parameters.samples),
           [](const CdmDecryptionSample& sample) -> bool {
@@ -325,7 +323,22 @@ CdmResponseType WvContentDecryptionModule::DecryptV16(
                 });
           });
 
-      if (is_any_protected) {
+      // A key does not need to be loaded if
+      // (a) the content consists of one or more samples and is entirely
+      //     clear data
+      // (b) (legacy) the content consists of clear lead/frame in a single
+      //     subsample. In earlier releases content was presented for decryption
+      //     as individual subsamples. If the clear frame is broken up across
+      //     multiple subsamples decryption, requests should be rejected
+      //     (b/110251447)
+      // TODO(b/149524614): Remove support for the legacy case
+      if (is_any_protected ||
+          (parameters.observe_legacy_fields && parameters.samples.size() == 1 &&
+           parameters.samples[0].subsamples.size() == 1 &&
+           !(parameters.samples[0].subsamples[0].flags &
+                 OEMCrypto_FirstSubsample &&
+             parameters.samples[0].subsamples[0].flags &
+                 OEMCrypto_LastSubsample))) {
         return KEY_NOT_FOUND_IN_SESSION;
       }
     }