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

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am: 67682ddf1a

Change-Id: Idb1f713da3002733152544dd6eae2da06119dbdb
This commit is contained in:
John "Juce" Bruce
2016-08-30 05:06:47 +00:00
committed by android-build-merger
parent 4a9c2fa2a1 67682ddf1a
commit eb153e78fc
4 changed files with 9 additions and 26 deletions
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2
libwvdrmengine/mediacrypto/include/WVCryptoPlugin.h
View File

@@ -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);
};

27
libwvdrmengine/mediacrypto/src/WVCryptoPlugin.cpp
View File

@@ -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;