Author Archives: daveti

About daveti

Interested in kernel hacking, compilers, machine learning and guitars.

Hacking Valgrind

This post talks about 3 commits I have recently added into my own valgrind tree [1], including the support for fsgsbase instructions, rdrand/rdseed instructions, and adding a new trapdoor (client request) to support gdb-like add-symbol-file command. Note that all these … Continue reading

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Valgrind trapdoor and fun

Valgrind has a client request mechanism, which allows a client to pass some information back to valgrind. This includes asks valgrind to do a logging in its own environment, tells valgrind a range of VA being used as a new … Continue reading

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Some notes on SGX OwnerEpoch and Sealing

Intel SGX has been there in the market for while. Yet there are still a lot of misundrestandings and mysteries about this technology. This post provides an introduction to Intel SGX OwnerEpoch and Sealing, discusses their security impacts, and speculates … Continue reading

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Kernel Code Execution Time Measurement (kcetm)

This post mainly talks about the correct usage of tsc counters provided by Intel x86/x86-64 architectures to measure the Linux kernel code execution time. Most of the content here is borrowed/inspired from [1]. Note that this is NOT a post … Continue reading

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Rowhammer Pine64

Rowhammer attacks have been well known, and gotten a lot of publications already. However, we notice that most rowhammers happened on x86 architecture due to the easy access to clflush from the user space. ARM architecture (both ARMv7 and ARMv8) … Continue reading

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“make deb-pkg” broken

Last time when I hacked the Linux kernel on Ubuntu, it was 4.4 on LTS 14.04. Time flies. Now I need to hack the kernel 4.13 again on LTS 16.04, and find the kernel build broken. It is fine that … Continue reading

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Running Multics on Linux (Fedora 27)

This post follows the “Multics Simulator Instructions”[1] (with some tweaks) to setup Multics simulator dps8m and run Multics on my Fedora 27. Other Linux distro (Ubuntu/Debian/Raspbian) may need some changes but basically work the same way. Experience the cutting-edge secure … Continue reading

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