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Disk: Fix out of bounds accesses in base ReadDriver

v0.3.0-dev
Paul Hollinsky 2021-11-19 14:14:55 -05:00
parent f8bfb243fa
commit 80cd4ae052
1 changed files with 11 additions and 9 deletions
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20
disk/diskreaddriver.cpp
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@ -14,19 +14,21 @@ optional<uint64_t> DiskReadDriver::readLogicalDisk(Communication& com, device_ev
const uint32_t idealBlockSize = getBlockSizeBounds().second; const uint32_t idealBlockSize = getBlockSizeBounds().second;
const uint64_t startBlock = pos / idealBlockSize; const uint64_t startBlock = pos / idealBlockSize;
const uint64_t posWithinFirstBlock = pos % idealBlockSize; const uint32_t posWithinFirstBlock = static_cast<uint32_t>(pos % idealBlockSize);
const uint64_t blocks = amount / idealBlockSize + (amount % idealBlockSize ? 1 : 0) + (posWithinFirstBlock ? 1 : 0); uint64_t blocks = amount / idealBlockSize + (amount % idealBlockSize ? 1 : 0);
if(blocks * idealBlockSize - posWithinFirstBlock < amount)
blocks++; // We need one more block to get the last partial block's worth
uint64_t blocksProcessed = 0; uint64_t blocksProcessed = 0;
while(blocksProcessed < blocks && timeout >= std::chrono::milliseconds::zero()) { while(blocksProcessed < blocks && timeout >= std::chrono::milliseconds::zero()) {
const uint64_t currentBlock = startBlock + blocksProcessed; const uint64_t currentBlock = startBlock + blocksProcessed;
const int intoOffset = std::min<int>((blocksProcessed * idealBlockSize) - posWithinFirstBlock, 0); const uint64_t intoOffset = std::max<uint64_t>((blocksProcessed * idealBlockSize) - posWithinFirstBlock, 0);
const auto posWithinCurrentBlock = (blocksProcessed ? 0 : posWithinFirstBlock); const uint32_t posWithinCurrentBlock = (blocksProcessed ? 0 : posWithinFirstBlock);
auto curAmt = idealBlockSize - posWithinCurrentBlock; uint32_t curAmt = idealBlockSize - posWithinCurrentBlock;
const auto amountLeft = amount - *ret; const auto amountLeft = amount - ret.value_or(0);
if(curAmt > amountLeft) if(curAmt > amountLeft)
curAmt = amountLeft; curAmt = static_cast<uint32_t>(amountLeft);
const bool useAlignedReadBuffer = (posWithinCurrentBlock != 0 || curAmt != idealBlockSize); const bool useAlignedReadBuffer = (posWithinCurrentBlock != 0 || curAmt != idealBlockSize);
if(useAlignedReadBuffer && alignedReadBuffer.size() < idealBlockSize) if(useAlignedReadBuffer && alignedReadBuffer.size() < idealBlockSize)
@ -34,7 +36,7 @@ optional<uint64_t> DiskReadDriver::readLogicalDisk(Communication& com, device_ev
auto start = std::chrono::high_resolution_clock::now(); auto start = std::chrono::high_resolution_clock::now();
auto readAmount = readLogicalDiskAligned(com, report, currentBlock * idealBlockSize, auto readAmount = readLogicalDiskAligned(com, report, currentBlock * idealBlockSize,
useAlignedReadBuffer ? alignedReadBuffer.data() : into + intoOffset, idealBlockSize, timeout); useAlignedReadBuffer ? alignedReadBuffer.data() : (into + intoOffset), idealBlockSize, timeout);
timeout -= std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::high_resolution_clock::now() - start); timeout -= std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::high_resolution_clock::now() - start);
if(!readAmount.has_value() || *readAmount == 0) { if(!readAmount.has_value() || *readAmount == 0) {
@ -50,7 +52,7 @@ optional<uint64_t> DiskReadDriver::readLogicalDisk(Communication& com, device_ev
if(!ret) if(!ret)
ret.emplace(); ret.emplace();
*ret += *readAmount; *ret += std::min<uint64_t>(*readAmount, curAmt);
blocksProcessed++; blocksProcessed++;
} }