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Make Defensive Copies in CopyBufferInChunks

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am: b305d99d3b

Change-Id: I6657bd3174202f061a003f0e8132075b807af2e9
This commit is contained in:
John W. Bruce
2018-05-24 17:04:27 -07:00
committed by android-build-merger
parent 7132c09585 b305d99d3b
commit f3b5d0408b
1 changed files with 9 additions and 10 deletions
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19
libwvdrmengine/cdm/core/src/crypto_session.cpp
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@@ -2358,7 +2358,7 @@ size_t CryptoSession::GenericEncryptionBlockSize(
OEMCryptoResult CryptoSession::CopyBufferInChunks( OEMCryptoResult CryptoSession::CopyBufferInChunks(
const CdmDecryptionParameters& params, const CdmDecryptionParameters& params,
OEMCrypto_DestBufferDesc buffer_descriptor) { OEMCrypto_DestBufferDesc full_buffer_descriptor) {
size_t remaining_encrypt_length = params.encrypt_length; size_t remaining_encrypt_length = params.encrypt_length;
uint8_t subsample_flags = OEMCrypto_FirstSubsample; uint8_t subsample_flags = OEMCrypto_FirstSubsample;
@@ -2374,19 +2374,18 @@ OEMCryptoResult CryptoSession::CopyBufferInChunks(
// calculating the new values. // calculating the new values.
remaining_encrypt_length -= chunk_size; remaining_encrypt_length -= chunk_size;
// Update the destination buffer with the new offset. // Update the destination buffer with the new offset. Because OEMCrypto
// can modify the OEMCrypto_DestBufferDesc during the call to
// OEMCrypto_CopyBuffer, (and is known to do so on some platforms) a new
// OEMCrypto_DestBufferDesc must be allocated for each call.
OEMCrypto_DestBufferDesc buffer_descriptor = full_buffer_descriptor;
switch (buffer_descriptor.type) { switch (buffer_descriptor.type) {
case OEMCrypto_BufferType_Clear: case OEMCrypto_BufferType_Clear:
buffer_descriptor.buffer.clear.address = buffer_descriptor.buffer.clear.address += additional_offset;
static_cast<uint8_t*>(params.decrypt_buffer) + buffer_descriptor.buffer.clear.max_length -= additional_offset;
params.decrypt_buffer_offset + additional_offset;
buffer_descriptor.buffer.clear.max_length =
params.decrypt_buffer_length -
(params.decrypt_buffer_offset + additional_offset);
break; break;
case OEMCrypto_BufferType_Secure: case OEMCrypto_BufferType_Secure:
buffer_descriptor.buffer.secure.offset = buffer_descriptor.buffer.secure.offset += additional_offset;
params.decrypt_buffer_offset + additional_offset;
break; break;
case OEMCrypto_BufferType_Direct: case OEMCrypto_BufferType_Direct:
// OEMCrypto_BufferType_Direct does not need modification. // OEMCrypto_BufferType_Direct does not need modification.