fix(hidpp): bounds-check raw report dispatch lambdas#551
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Filter lambdas in hidpp::Device and hidpp10::ReceiverMonitor indexed the raw byte buffer at Offset::Type, ::DeviceIndex, and ::SubID without checking that the buffer was large enough. A short hidraw read (possible from a malicious or buggy device, or partial reads under load) would cause an out-of-bounds access on std::vector::operator[]. Reject reports shorter than the offsets we read.
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Summary
The filter lambdas in
hidpp::Device::_setupReportsAndInitandhidpp10::ReceiverMonitor::_ready/waitForDeviceindex the raw byte buffer atOffset::Type,Offset::DeviceIndex, andOffset::SubIDwithout checking that the buffer is large enough:return (report[Offset::Type] == Report::Type::Short || ...) && (report[Offset::DeviceIndex] == index);reportis the rawstd::vector<uint8_t>returned byread(hidraw_fd)and may be shorter than 2 bytes (a buggy or malicious device, or a partial read).std::vector::operator[]does no bounds checking, so this is undefined behaviour.Fix
Add a
report.size() <= Offset::DeviceIndex(orOffset::SubID) guard at the top of each filter lambda.Test plan