Sarah Jamie Lewis

Executive Director @OpenPriv. Privacy Researcher

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[Sarah Jamie Lewis @SarahJamieLewis]

Hi I'm Sarah, Executive Director of Open Privacy (@OpenPriv) - A Canadian non-profit society dedicated to researching & building privacy enhancing tools that empower people & marginalized communities.

Donate to support our work: https://t.co/UZ8Za3VE5d

[Sarah Jamie Lewis @SarahJamieLewis]

It's been a good 15 years (joined 2007).

Twitter helped me travel the world, meet so many awesome people, make amazing friends (including my long term love).

See you all on the other side.

https://t.co/dEU0rCAdSt

[Sarah Jamie Lewis @SarahJamieLewis]

One of the suggestions I received yesterday was to implement some classic crypto attacks on stream.

To start let's go through cryptopals challenges which cover some really nice ones.

Come hang out/ask questions/play along!

Twitch: https://t.co/Y8B5mnTG4g

[Sarah Jamie Lewis @SarahJamieLewis]

Today on stream: Now that we can run Doom on our little risc-v OS we should probably start to make it playable (start setting up interrupt controllers / keyboard &mouse drivers / a clock etc.).

Twitch: https://t.co/Y8B5mnTG4g

[Sarah Jamie Lewis @SarahJamieLewis]

This was like ~40 hours of to go from zero to an OS that can run Doom. Very happy we got there!

I'm still experimenting with streaming but If you like this kind of stuff and would like to see more of it, please consider following/subscribing on Twitch: https://t.co/Y8B5mnTG4g

[Sarah Jamie Lewis @SarahJamieLewis]

Today on stream, now that Doom is technically running on our little risc-v operating system we are going try and get it working... (OSDev and Chill)

Come hang out / ask questions / play along.

Twitch: https://t.co/CkenUrlxHS

[Sarah Jamie Lewis @SarahJamieLewis]

Updated source code for both the OS and a link to the fbDoom changes needed for riscv/our OS ecall convention can be found here: https://t.co/o47yAzBZcl

[Sarah Jamie Lewis @SarahJamieLewis]

Today on stream, with the VGA driver and ELF loader written, we are finally going to get Doom running on our little risc-v operating system - after we write a few environment calls for libc hooks...

Come hang out / ask questions / play along.

Twitch: https://t.co/Y8B5mnTG4g

[Sarah Jamie Lewis @SarahJamieLewis]

Plan for the stream today is to implement seed pruning into our little Super Mario Bros. Fuzzer to prevent our backlog from filling up with low quality inputs.

#fuzzing

Twitch: https://t.co/CkenUrlxHS

[Sarah Jamie Lewis @SarahJamieLewis]

@dascandy42 Emulator for now (QEMU virt machine specifically).

Rough medium-term plan is to write a throw-away bios-less OS to start to get back to grips with risc-v/osdev/etc, then throw it away, and start again with something like OpenSBI targeting a more realistic machine.

[Sarah Jamie Lewis @SarahJamieLewis]

Today on stream: Can we get our little risc-v operating system to run Doom? Let's find out. (OSDev & Chill)

Twitch: https://t.co/CkenUrlxHS

[Sarah Jamie Lewis @SarahJamieLewis]

Update: after I had dinner and did other things for a few hours I took one quick look at the elf loader...found 6 (!) bugs, and it now works....

Our little OS can load a elf & (begin) execution, will go through fixes on Friday before we dive into actually getting doom to run...

[Sarah Jamie Lewis @SarahJamieLewis]

The answer: not today...we got Doom compiling for riscv with some stdlib stubs and then set about writing an elf loader for our kernel, but the clock ran out before we had shaken out the bugs there.

We will try again, with fresh eyes, on Friday!

[Sarah Jamie Lewis @SarahJamieLewis]

Today on stream we formalized PCI enumeration, and got a quick little QEMU VGA driver up and running. (Now on youtube: https://t.co/Eo7SxV5cdI)

Source: https://t.co/o47yAzBZcl

Next OSDev stream we will see if we can get Doom running on our little OS!

[Sarah Jamie Lewis @SarahJamieLewis]

Today on stream I'm going to be working on the seed selection algorithm in my little NES/Super Mario Bros. fuzzer.

Come hang out/learn about fuzzing

https://t.co/Y8B5mnTG4g

[Sarah Jamie Lewis @SarahJamieLewis]

Let's finish off setting up page tables and jump into playing around with PCI.

Twitch: https://t.co/Y8B5mnTG4g

[Sarah Jamie Lewis @SarahJamieLewis]

For those who were playing along today: We dropped into S-Mode and then spent some time setting up page tables.

After dinner, I worked out the reason why we were page faulting - I'll cover it next stream (or see mastodon for summary).

Updated code: https://t.co/o47yAzBZcl

[Sarah Jamie Lewis @SarahJamieLewis]

Today on stream: OSDev and Chill (Let's Build an OS: Day 1)

We're going to build on the little bootloader we wrote last time, dive into supervisor mode, and get to grips with paging and virtual memory.

Come hang out / chat / ask questions.

Twitch: https://t.co/Y8B5mnTG4g

[Sarah Jamie Lewis @SarahJamieLewis]

@pennywhispered Still experimenting with format/timing but I'm planning to at least do another OS dev stream tomorrow. (And I'll likely upload this last one to youtube)

Tentative twitch schedule is here: https://t.co/1I4ju5ETsR

[Sarah Jamie Lewis @SarahJamieLewis]

Today on stream: We're going to ease into building a little operating system by reading some riscv docs, setting up a development environment, and writing a little bootloader.

Come hang out / chat / ask questions.

Twitch: https://t.co/Y8B5mnTG4g