From 8f7ed34c3adff12755f9f4d5c4905353c7301308 Mon Sep 17 00:00:00 2001
From: Jeff Tinker <jtinker@google.com>
Date: Tue, 23 Apr 2013 15:57:10 -0700
Subject: [PATCH] Wrap Init Data in PSSH Box

The Java APIs only easily expose getting the PSSH data blob, not the full PSSH
box.  So that apps do not have to do extra work, wrapping the PSSH data blob in a
PSSH box again, we do it for them in the DrmPlugin.

Includes requisite changes to the Unit tests

Bug: 8584241

Merge of https://widevine-internal-review.googlesource.com/#/c/5142/
from the Widevine CDM repository.

Change-Id: Ifb5910dd52380e1b591ecdf1e4273c8d9f3294cc
---
 libwvdrmengine/mediadrm/src/WVDrmPlugin.cpp   | 22 +++++++++++++--
 .../mediadrm/test/WVDrmPlugin_test.cpp        | 28 +++++++++++++------
 2 files changed, 39 insertions(+), 11 deletions(-)

diff --git a/libwvdrmengine/mediadrm/src/WVDrmPlugin.cpp b/libwvdrmengine/mediadrm/src/WVDrmPlugin.cpp
index 164f78c2..b5893c6b 100644
--- a/libwvdrmengine/mediadrm/src/WVDrmPlugin.cpp
+++ b/libwvdrmengine/mediadrm/src/WVDrmPlugin.cpp
@@ -8,6 +8,7 @@
 
 #include "WVDrmPlugin.h"
 
+#include <endian.h>
 #include <sstream>
 #include <string>
 #include <vector>
@@ -129,9 +130,24 @@ status_t WVDrmPlugin::getKeyRequest(
   } else {
     return android::ERROR_DRM_CANNOT_HANDLE;
   }
-
   CdmSessionId cdmSessionId(sessionId.begin(), sessionId.end());
-  CdmInitData cdmInitData(initData.begin(), initData.end());
+
+  // Build PSSH box for PSSH data in initData.
+  static const char psshPrefix[] = {
+    0, 0, 0, 0,                                     // Total size
+    'p', 's', 's', 'h',                             // "PSSH"
+    0, 0, 0, 0,                                     // Flags - must be zero
+    0xED, 0xEF, 0x8B, 0xA9, 0x79, 0xD6, 0x4A, 0xCE, // Widevine UUID
+    0xA3, 0xC8, 0x27, 0xDC, 0xD5, 0x1D, 0x21, 0xED,
+    0, 0, 0, 0                                      // Size of initData
+  };
+  CdmInitData psshBox(psshPrefix, sizeof(psshPrefix) / sizeof(uint8_t));
+  psshBox.append(reinterpret_cast<const char*>(initData.array()),
+                 initData.size());
+  uint32_t* psshBoxSize = reinterpret_cast<uint32_t*>(&psshBox[0]);
+  uint32_t* initDataSize = reinterpret_cast<uint32_t*>(&psshBox[28]);
+  *initDataSize = htonl(initData.size());
+  *psshBoxSize = htonl(psshBox.size());
 
   CdmAppParameterMap cdmParameters;
   for (size_t i = 0; i < optionalParameters.size(); ++i) {
@@ -147,7 +163,7 @@ status_t WVDrmPlugin::getKeyRequest(
   CdmKeyMessage keyRequest;
   string cdmDefaultUrl;
 
-  CdmResponseType res = mCDM->GenerateKeyRequest(cdmSessionId, cdmInitData,
+  CdmResponseType res = mCDM->GenerateKeyRequest(cdmSessionId, psshBox,
                                                  cdmLicenseType,
                                                  cdmParameters, &keyRequest,
                                                  &cdmDefaultUrl);
diff --git a/libwvdrmengine/mediadrm/test/WVDrmPlugin_test.cpp b/libwvdrmengine/mediadrm/test/WVDrmPlugin_test.cpp
index 01eeb58d..6a21ba7d 100644
--- a/libwvdrmengine/mediadrm/test/WVDrmPlugin_test.cpp
+++ b/libwvdrmengine/mediadrm/test/WVDrmPlugin_test.cpp
@@ -166,9 +166,9 @@ TEST_F(WVDrmPluginTest, GeneratesKeyRequests) {
   MockCrypto crypto;
   WVDrmPlugin plugin(&cdm, &crypto);
 
-  static const uint32_t kInitDataSize = 128;
+  static const size_t kInitDataSize = 128;
   uint8_t initDataRaw[kInitDataSize];
-  static const uint32_t kRequestSize = 256;
+  static const size_t kRequestSize = 256;
   uint8_t requestRaw[kRequestSize];
   FILE* fp = fopen("/dev/urandom", "r");
   fread(initDataRaw, sizeof(uint8_t), kInitDataSize, fp);
@@ -178,6 +178,20 @@ TEST_F(WVDrmPluginTest, GeneratesKeyRequests) {
   Vector<uint8_t> initData;
   initData.appendArray(initDataRaw, kInitDataSize);
 
+  static const uint8_t psshPrefix[] = {
+    0, 0, 0, 32 + kInitDataSize,                    // Total size
+    'p', 's', 's', 'h',                             // "PSSH"
+    0, 0, 0, 0,                                     // Flags - must be zero
+    0xED, 0xEF, 0x8B, 0xA9, 0x79, 0xD6, 0x4A, 0xCE, // Widevine UUID
+    0xA3, 0xC8, 0x27, 0xDC, 0xD5, 0x1D, 0x21, 0xED,
+    0, 0, 0, kInitDataSize                          // Size of initData
+  };
+  static const size_t kPsshPrefixSize = sizeof(psshPrefix);
+  static const size_t kPsshBoxSize = kPsshPrefixSize + kInitDataSize;
+  uint8_t psshBox[kPsshBoxSize];
+  memcpy(psshBox, psshPrefix, kPsshPrefixSize);
+  memcpy(psshBox + kPsshPrefixSize, initDataRaw, kInitDataSize);
+
   CdmKeyMessage cdmRequest(requestRaw, requestRaw + kRequestSize);
 
   KeyedVector<String8, String8> parameters;
@@ -196,8 +210,7 @@ TEST_F(WVDrmPluginTest, GeneratesKeyRequests) {
     InSequence calls;
 
     EXPECT_CALL(cdm, GenerateKeyRequest(cdmSessionId,
-                                        ElementsAreArray(initDataRaw,
-                                                         kInitDataSize),
+                                        ElementsAreArray(psshBox, kPsshBoxSize),
                                         kLicenseTypeOffline, cdmParameters, _,
                                         _))
         .WillOnce(DoAll(SetArgPointee<4>(cdmRequest),
@@ -205,10 +218,9 @@ TEST_F(WVDrmPluginTest, GeneratesKeyRequests) {
                         Return(wvcdm::KEY_MESSAGE)));
 
     EXPECT_CALL(cdm, GenerateKeyRequest(cdmSessionId,
-                                        ElementsAreArray(initDataRaw,
-                                                         kInitDataSize),
-                                        kLicenseTypeStreaming, cdmParameters,
-                                        _, _))
+                                        ElementsAreArray(psshBox, kPsshBoxSize),
+                                        kLicenseTypeStreaming, cdmParameters, _,
+                                        _))
         .WillOnce(DoAll(SetArgPointee<4>(cdmRequest),
                         SetArgPointee<5>(kDefaultUrl),
                         Return(wvcdm::KEY_MESSAGE)));