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Merge "cas: validate shared buffer size before using" into oc-mr1-dev

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Chong Zhang 2017-11-10 09:01:08 +00:00 committed by Android (Google) Code Review
commit 6a8fab9781
1 changed files with 52 additions and 1 deletions
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53
cas/1.0/default/DescramblerImpl.cpp
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@ -18,8 +18,9 @@
#define LOG_TAG "android.hardware.cas@1.0-DescramblerImpl"
#include <hidlmemory/mapping.h>
#include <media/hardware/CryptoAPI.h>
#include <media/cas/DescramblerAPI.h>
#include <media/hardware/CryptoAPI.h>
#include <media/stagefright/foundation/AUtils.h>
#include <utils/Log.h>
#include "DescramblerImpl.h"
@ -70,6 +71,11 @@ Return<bool> DescramblerImpl::requiresSecureDecoderComponent(
return mPlugin->requiresSecureDecoderComponent(String8(mime.c_str()));
}
static inline bool validateRangeForSize(
uint64_t offset, uint64_t length, uint64_t size) {
return isInRange<uint64_t, uint64_t>(0, size, offset, length);
}
Return<void> DescramblerImpl::descramble(
ScramblingControl scramblingControl,
const hidl_vec<SubSample>& subSamples,
@ -81,12 +87,57 @@ Return<void> DescramblerImpl::descramble(
ALOGV("%s", __FUNCTION__);
sp<IMemory> srcMem = mapMemory(srcBuffer.heapBase);
// Validate if the offset and size in the SharedBuffer is consistent with the
// mapped ashmem, since the offset and size is controlled by client.
if (srcMem == NULL) {
ALOGE("Failed to map src buffer.");
_hidl_cb(toStatus(BAD_VALUE), 0, NULL);
return Void();
}
if (!validateRangeForSize(
srcBuffer.offset, srcBuffer.size, (uint64_t)srcMem->getSize())) {
ALOGE("Invalid src buffer range: offset %llu, size %llu, srcMem size %llu",
srcBuffer.offset, srcBuffer.size, (uint64_t)srcMem->getSize());
android_errorWriteLog(0x534e4554, "67962232");
_hidl_cb(toStatus(BAD_VALUE), 0, NULL);
return Void();
}
// use 64-bit here to catch bad subsample size that might be overflowing.
uint64_t totalBytesInSubSamples = 0;
for (size_t i = 0; i < subSamples.size(); i++) {
totalBytesInSubSamples += (uint64_t)subSamples[i].numBytesOfClearData +
subSamples[i].numBytesOfEncryptedData;
}
// Further validate if the specified srcOffset and requested total subsample size
// is consistent with the source shared buffer size.
if (!validateRangeForSize(srcOffset, totalBytesInSubSamples, srcBuffer.size)) {
ALOGE("Invalid srcOffset and subsample size: "
"srcOffset %llu, totalBytesInSubSamples %llu, srcBuffer size %llu",
srcOffset, totalBytesInSubSamples, srcBuffer.size);
android_errorWriteLog(0x534e4554, "67962232");
_hidl_cb(toStatus(BAD_VALUE), 0, NULL);
return Void();
}
void *srcPtr = (uint8_t *)(void *)srcMem->getPointer() + srcBuffer.offset;
void *dstPtr = NULL;
if (dstBuffer.type == BufferType::SHARED_MEMORY) {
// When using shared memory, src buffer is also used as dst,
// we don't map it again here.
dstPtr = srcPtr;
// In this case the dst and src would be the same buffer, need to validate
// dstOffset against the buffer size too.
if (!validateRangeForSize(dstOffset, totalBytesInSubSamples, srcBuffer.size)) {
ALOGE("Invalid dstOffset and subsample size: "
"dstOffset %llu, totalBytesInSubSamples %llu, srcBuffer size %llu",
dstOffset, totalBytesInSubSamples, srcBuffer.size);
android_errorWriteLog(0x534e4554, "67962232");
_hidl_cb(toStatus(BAD_VALUE), 0, NULL);
return Void();
}
} else {
native_handle_t *handle = const_cast<native_handle_t *>(
dstBuffer.secureMemory.getNativeHandle());