Fix cens Mode in Android CDM am: e0f4942b8f am: 442099fb15

am: 67682ddf1a

Change-Id: Idb1f713da3002733152544dd6eae2da06119dbdb

libwvdrmengine/cdm/core/include/wv_cdm_types.h

@@ -282,11 +282,9 @@ enum CdmCipherMode {
 struct CdmCencPatternEncryptionDescriptor {
   size_t encrypt_blocks;  // number of 16 byte blocks to decrypt
   size_t skip_blocks;     // number of 16 byte blocks to leave in clear
-  size_t offset_blocks;   // offset into the pattern for this call, in blocks
   CdmCencPatternEncryptionDescriptor()
       : encrypt_blocks(0),
-        skip_blocks(0),
-        offset_blocks(0) {}
+        skip_blocks(0) {}
 };
 
 struct CdmDecryptionParameters {

libwvdrmengine/cdm/core/src/crypto_session.cpp

@@ -689,7 +689,7 @@ CdmResponseType CryptoSession::Decrypt(const CdmDecryptionParameters& params) {
     OEMCrypto_CENCEncryptPatternDesc pattern_descriptor;
     pattern_descriptor.encrypt = params.pattern_descriptor.encrypt_blocks;
     pattern_descriptor.skip = params.pattern_descriptor.skip_blocks;
-    pattern_descriptor.offset = params.pattern_descriptor.offset_blocks;
+    pattern_descriptor.offset = 0;  // Deprecated field
     AutoLock auto_lock(crypto_lock_);
     // Check if key needs to be selected
     if (params.is_encrypted) {

libwvdrmengine/mediacrypto/include/WVCryptoPlugin.h

@@ -47,7 +47,7 @@ class WVCryptoPlugin : public android::CryptoPlugin {
   wvcdm::CdmSessionId configureTestMode(const void* data, size_t size);
   static wvcdm::CdmResponseType countEncryptedBlocksInPatternedRange(
       size_t range, size_t startingOffset, const Pattern& pattern,
-      size_t startingPatternOffset, uint64_t* result);
+      uint64_t* result);
   static void incrementIV(uint64_t increaseBy, std::vector<uint8_t>* ivPtr);
 };
 

libwvdrmengine/mediacrypto/src/WVCryptoPlugin.cpp

@@ -146,7 +146,6 @@ ssize_t WVCryptoPlugin::decrypt(bool secure, const uint8_t key[KEY_ID_SIZE],
   size_t blockOffset = 0;
   const size_t patternLengthInBytes =
       (pattern.mEncryptBlocks + pattern.mSkipBlocks) * kAESBlockSize;
-  size_t patternOffsetInBytes = 0;
 
   for (size_t i = 0; i < numSubSamples; ++i) {
     const SubSample& subSample = subSamples[i];
@@ -187,7 +186,6 @@ ssize_t WVCryptoPlugin::decrypt(bool secure, const uint8_t key[KEY_ID_SIZE],
       params.encrypt_buffer = source + offset;
       params.encrypt_length = subSample.mNumBytesOfClearData;
       params.block_offset = 0;
-      params.pattern_descriptor.offset_blocks = 0;
       params.decrypt_buffer_offset = offset;
       params.subsample_flags = clearFlags;
 
@@ -238,12 +236,6 @@ ssize_t WVCryptoPlugin::decrypt(bool secure, const uint8_t key[KEY_ID_SIZE],
       params.encrypt_buffer = source + offset;
       params.encrypt_length = subSample.mNumBytesOfEncryptedData;
       params.block_offset = blockOffset;
-      // Note that the pattern offset calculation relies intentionally on
-      // integer division's flooring behavior. If we are partway through a
-      // crypto block, we should return the offset of the pattern block we are
-      // partway through.
-      size_t patternOffsetInBlocks = patternOffsetInBytes / kAESBlockSize;
-      params.pattern_descriptor.offset_blocks = patternOffsetInBlocks;
       params.decrypt_buffer_offset = offset;
       params.subsample_flags = encryptedFlags;
 
@@ -301,7 +293,7 @@ ssize_t WVCryptoPlugin::decrypt(bool secure, const uint8_t key[KEY_ID_SIZE],
         } else {
           res = countEncryptedBlocksInPatternedRange(
               subSample.mNumBytesOfEncryptedData, blockOffset, pattern,
-              patternOffsetInBlocks, &increment);
+              &increment);
           if (!isCdmResponseTypeSuccess(res)) {
             // Swallow the specifics of the error to obscure decrypt internals.
             return kErrorCDMGeneric;
@@ -312,12 +304,6 @@ ssize_t WVCryptoPlugin::decrypt(bool secure, const uint8_t key[KEY_ID_SIZE],
         // Update the block offset
         blockOffset = (blockOffset + subSample.mNumBytesOfEncryptedData) %
             kAESBlockSize;
-
-        if (patternLengthInBytes > 0) {
-          patternOffsetInBytes =
-              (patternOffsetInBytes + subSample.mNumBytesOfEncryptedData) %
-                  patternLengthInBytes;
-        }
       } else if (mode == kMode_AES_CBC && patternLengthInBytes == 0) {
         // If there is no pattern, assume cbc1 mode and update the IV.
 
@@ -363,14 +349,13 @@ ssize_t WVCryptoPlugin::decrypt(bool secure, const uint8_t key[KEY_ID_SIZE],
 
 CdmResponseType WVCryptoPlugin::countEncryptedBlocksInPatternedRange(
     size_t range, size_t startingOffset, const Pattern& pattern,
-    size_t startingPatternOffset, uint64_t* result) {
+    uint64_t* result) {
   uint64_t blocksPassed = 0;
   size_t bytesRemaining = range;
-  size_t patternOffset = startingPatternOffset;
+  size_t patternPosition = 0;
   size_t patternLength = pattern.mEncryptBlocks + pattern.mSkipBlocks;
 
-  if (result == NULL || startingOffset >= kAESBlockSize ||
-      startingPatternOffset >= patternLength) {
+  if (result == NULL || startingOffset >= kAESBlockSize) {
     return wvcdm::UNKNOWN_ERROR;
   }
 
@@ -379,10 +364,10 @@ CdmResponseType WVCryptoPlugin::countEncryptedBlocksInPatternedRange(
   size_t bytesNeededToCompleteABlock = kAESBlockSize - startingOffset;
   while (bytesRemaining >= bytesNeededToCompleteABlock) {
     bytesRemaining -= bytesNeededToCompleteABlock;
-    if (patternOffset < pattern.mEncryptBlocks) {
+    if (patternPosition < pattern.mEncryptBlocks) {
       ++blocksPassed;
     }
-    patternOffset = (patternOffset + 1) % patternLength;
+    patternPosition = (patternPosition + 1) % patternLength;
 
     // After the first block, we only concern ourselves with complete blocks.
     bytesNeededToCompleteABlock = kAESBlockSize;