From ae1711acc04f1093ceec731811632106407e36fa Mon Sep 17 00:00:00 2001
From: Fred Gylys-Colwell <fredgc@google.com>
Date: Tue, 31 Mar 2015 15:09:45 -0700
Subject: [PATCH] Add backward compatibility to OEMCrypto_CopyBuffer

Merge from Widevine repository of http://go/wvgerrit/13912

This CL falls back to OEMCrypto_DecryptCTR if the oemcrypto library
does not implement OEMCrypto_CopyBuffer.  This allows devices with
oem crypto version 9 to function as they previously did.

Change-Id: Id3a4a94b1fd559f426ee260cfbf7077fa9101d8b
---
 .../cdm/core/src/crypto_session.cpp           | 25 +++++++++++--------
 .../mock/src/oemcrypto_engine_mock.cpp        | 10 +++++---
 .../oemcrypto/mock/src/oemcrypto_mock.cpp     |  7 +++---
 3 files changed, 24 insertions(+), 18 deletions(-)

diff --git a/libwvdrmengine/cdm/core/src/crypto_session.cpp b/libwvdrmengine/cdm/core/src/crypto_session.cpp
index 4ecbad6b..846282a6 100644
--- a/libwvdrmengine/cdm/core/src/crypto_session.cpp
+++ b/libwvdrmengine/cdm/core/src/crypto_session.cpp
@@ -660,25 +660,28 @@ CdmResponseType CryptoSession::Decrypt(const CdmDecryptionParameters& params) {
       break;
   }
 
-  OEMCryptoResult sts;
-  if (params.is_encrypted) {
+  OEMCryptoResult sts = OEMCrypto_ERROR_NOT_IMPLEMENTED;
+  if (!params.is_encrypted) {
+    sts = OEMCrypto_CopyBuffer(requested_security_level_,
+                               params.encrypt_buffer, params.encrypt_length,
+                               &buffer_descriptor, params.subsample_flags);
+  }
+  if (params.is_encrypted || sts == OEMCrypto_ERROR_NOT_IMPLEMENTED) {
     AutoLock auto_lock(crypto_lock_);
     // Check if key needs to be selected
-    if (key_id_ != *params.key_id) {
-      if (SelectKey(*params.key_id)) {
-        key_id_ = *params.key_id;
-      } else {
-        return NEED_KEY;
+    if (params.is_encrypted) {
+      if (key_id_ != *params.key_id) {
+        if (SelectKey(*params.key_id)) {
+          key_id_ = *params.key_id;
+        } else {
+          return NEED_KEY;
+        }
       }
     }
     sts = OEMCrypto_DecryptCTR(
         oec_session_id_, params.encrypt_buffer, params.encrypt_length,
         params.is_encrypted, &(*params.iv).front(), params.block_offset,
         &buffer_descriptor, params.subsample_flags);
-  } else {
-    sts = OEMCrypto_CopyBuffer(requested_security_level_,
-                               params.encrypt_buffer, params.encrypt_length,
-                               &buffer_descriptor, params.subsample_flags);
   }
 
   switch (sts) {
diff --git a/libwvdrmengine/oemcrypto/mock/src/oemcrypto_engine_mock.cpp b/libwvdrmengine/oemcrypto/mock/src/oemcrypto_engine_mock.cpp
index f93f4540..ed717639 100644
--- a/libwvdrmengine/oemcrypto/mock/src/oemcrypto_engine_mock.cpp
+++ b/libwvdrmengine/oemcrypto/mock/src/oemcrypto_engine_mock.cpp
@@ -1068,10 +1068,12 @@ OEMCryptoResult SessionContext::DecryptCTR(
     OEMCryptoBufferType buffer_type) {
   // If the data is clear, we do not need a current key selected.
   if (!is_encrypted) {
-    if (buffer_type == OEMCrypto_BufferType_Direct)
-      return OEMCrypto_ERROR_NOT_IMPLEMENTED;
-    memcpy(reinterpret_cast<uint8_t*>(clear_data), cipher_data,
-           cipher_data_length);
+    if (buffer_type != OEMCrypto_BufferType_Direct){
+      memcpy(reinterpret_cast<uint8_t*>(clear_data), cipher_data,
+             cipher_data_length);
+      return OEMCrypto_SUCCESS;
+    }
+    // For reference implementation, we quietly drop the clear direct video.
     return OEMCrypto_SUCCESS;
   }
 
diff --git a/libwvdrmengine/oemcrypto/mock/src/oemcrypto_mock.cpp b/libwvdrmengine/oemcrypto/mock/src/oemcrypto_mock.cpp
index f8806ee3..7ca9e8b3 100644
--- a/libwvdrmengine/oemcrypto/mock/src/oemcrypto_mock.cpp
+++ b/libwvdrmengine/oemcrypto/mock/src/oemcrypto_mock.cpp
@@ -536,10 +536,11 @@ OEMCryptoResult SetDestination(OEMCrypto_DestBufferDesc* out_buffer,
           + out_buffer->buffer.secure.offset;
       *max_length =  out_buffer->buffer.secure.max_length;
       break;
-    default:
     case OEMCrypto_BufferType_Direct:
-      return OEMCrypto_ERROR_NOT_IMPLEMENTED;
+      *destination = NULL;
       break;
+    default:
+      return OEMCrypto_ERROR_INVALID_CONTEXT;
   }
 
   if (out_buffer->type != OEMCrypto_BufferType_Direct
@@ -616,7 +617,7 @@ OEMCryptoResult OEMCrypto_CopyBuffer(const uint8_t *data_addr,
                                        &max_length);
   if (sts != OEMCrypto_SUCCESS) return sts;
 
-  memcpy(destination, data_addr, data_length);
+  if (destination != NULL) memcpy(destination, data_addr, data_length);
   return OEMCrypto_SUCCESS;
 }