OCTOPUS

Samuel AUBERTIN - EURECOM - 2022

OCTOPUS is a Spectre V1 (Bounds Check Bypass) + V2 (Branch Target Injection) compiler flag tester.

It measures the success rate of the attacks using different compilers:

• GCC
• CLANG

And compilation/linking flags such as:

• Optimisation levels (-O)
• Static/dynamic linking
• Masking and lfence as mitigation against Spectre V1
• RETPOLINE as mitigation against Spectre V2

Results

Results are stored as JSON objects in an unique file for each run, following this pattern: result-$(UUID).json

Dependencies

• clang and lld
• gcc
• sftp
• uuid
• The libC static symbols: glibc-static

Execution

Will build, execute and upload the results.

make

Build only

make [-j XXX] build where XXX is the number of parallel processes.

Results aggregation

Results are automatically uploaded to a server with a dedicated account using sftp.

Here is an exhaustive list of the data sent:

• CPU model name and microcode version.
• Kernel version and compilation date.
• GCC and clang versions.
• The list of mitigations enabled at runtime.
• The cache timings of the processor computed by the calibrate_threshold() function.
• Each spectre execution success rate.

NONE of this data will be used for anyhting else except this experiment.

References

Both implementations are heavily inspired by:

• ErikAugust gist
• genua GmbH PoC