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Linux kernel hacker and maintainer etc.

OpenPGP: 3AB05486C7752FE1
And neither uses heap. It needs bit over 3 kB of stack in the worst case scenario so should be fairly sustainable in many scenarios.
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Jarkko Sakkinen

Edited 1 year ago

Great my little zmodem2 crate is now supporting no_std. Not that useful yet before I have made file transfer API sequential (repeated calls, one per subpacket), or even fully async compatible (or postpone async to 0.2).

https://github.com/jarkkojs/zmodem2/commit/bc83180cacf04b5611c4068062408ef0ed75f797

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also need to make unescaping a separate stage to get clean (and fast) async implementation. now that escaping/unescaping is data instead of code it factors down the complexity of the original problem to half.

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Jarkko Sakkinen

sometimes the most #fortran solution is the best :-) not pretty, probably not too “rustacean” but gets the job done…

https://github.com/jarkkojs/zmodem2/commit/a4ad4508a99b66f46ab9daf0f08956c532285107

now it is pretty easy also add quirks later on without having to maintain a grazy ruleset.

#rustlang

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Edited 1 year ago

November 2023 - My Linux Kernel work

"-Wstringop-overflow

Late in October I sent a patch to globally enable the -Wstringop-overflow compiler option, which finally landed in linux-next on November 28th. It’s expected to be merged into mainline during the next merge window, likely in the last couple of weeks of December, but “We’ll see”. I plan to send a pull request for this to Linus when the time is right. 🙂 [...]"

You can read the whole post here:
https://embeddedor.com/blog/2023/12/05/november-2023-linux-kernel-work/

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or at least time saver
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Jarkko Sakkinen

core::array::from_fn is a life-saver #rustlang

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Jarkko Sakkinen

My #kernel (smoke) #testing ground: https://github.com/jarkkojs/buildroot-tpmdd

I think it is useful enough also update to MAINTAINERS. I’ve also tweaked #qemu scripts to automatically put #swtpm on background and some options what sort of TPM ought to be emulated.

#buildroot #linux

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@almenal99 i have no strong opinions on text editors, which is probably obvious already since i switch it every 10-20 years at most :-) it feels to me like discussing whether bosch or makita is superior if i was doing renovations sort of...
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@mo8it yeah, exactly. this was getting too insane :-) i liked vim the most when it did not have many plugins... then it also did not matter much which vim version happened to be around.
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Started this just a bit over a week ago and circa 90 commits done :-) I desperately need this myself and the stack has been a trainwreck for literally decades, and far behind what MS-DOS provided, which is a disgrace...
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Jarkko Sakkinen

Learned how async works in Rust and it looks like straight-forward to convert #zmodem2 crate to that as I have state machine alike structure for both send and return. Given how slow these transfers I make it async only, not async opt-in feature.

After that only some minor things need to be added and fixed and I can finally start gluing it to https://github.com/jarkkojs/tior and start working on its UI again.

For tior I’ll switch also switch to serial2 crate, which provides simpler API, a pro-active maintainer and fully working Windows serial support, which is not the case with seriaport.

With the asynchronous ZMODEM crate (right now the standard is invoking external program) it is possible to implement file transfer dialog, which shows progress, cancels the transfer according to the specification and generally not get a feeling that system is somehow halted :-)

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Hope everyone noted that I used words "mitigate" and "decrease", not e.g. "address" or "protect from" :-) Security is (and always has been) all about making breaking in expensive and visible enough to the level that the price is too high than the value of the asset protected. It is not that much different from physical world where you decide which sort of locks, doors etc. your house needs so that no one wants to rob your property.
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Jarkko Sakkinen

Edited 1 year ago

James Bottomley posted new version of the #HMAC encryption patches for #TPM2: https://lore.kernel.org/linux-integrity/20231127190854.13310-1-James.Bottomley@HansenPartnership.com/T/#t

I spent some time refactoring the tpm_buf changes because they were the major glitch for me in the earlier versions, and those patches have been included now to this series, which is of course great. The series is probably rather sooner than later ready for inclusion to the mainline.

This adds up to the TPM2 sealed hard drive encryption by mitigating bus interposers by a factor. An interposer is an actor intercepting traffic between the CPU and a discrete TPM chip (i.e. not firmware TPM).

A bus interposer can reset a TPM and replay PCR’s as the chip returns to its initial state, which resets them. To mitigate this, kernel creates HMAC session for each TPM transaction and derives session key from the so.called null hierarchy, which essentially provides a new random seed per TPM reset.

Therefore, interposer’s ability to reset TPM decreases because kernel will not be able to communicate with the TPM and that way indirectly a malicious act can be detected by far better chances than ever before.

IMHO, this fits quite nicely to the stuff that #OpenSUSE and #Ubuntu have been working on lately.

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@occhiolist sure np :-)
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@occhiolist TBH, I had to do a web search to find out what systemd-homed even is :-) So I guess I don’t possess that information.

My guess is that systemd-homed should not need to support at least when having LVM on top. User space is unaware that there even is encryption for the most part (except tools that specifically communicate with firmware/UEFI/MOK for e.g. grabbing a recovery key). For me it is pretty hard to make a corner case but I don’t have hard data. on this one. Hope this helps.

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Jarkko Sakkinen

Edited 1 year ago
I use now #TPM2 sealed LVM/LUKS2 encrypted partitioning in my Linux desktop. No need to type password anymore when booting up great. #Linux #TPM
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Jarkko Sakkinen

I switched to #helix editor because three advantages weight me more than disadvantage of having to learn away for #vim shortcuts:

  1. Too much legacy.
  2. Too many plugins.
  3. It is a varying challenge to install the latest version #neovim, which anyway needs to be done in order not to break init.lua (and that big pile of plugins).

So for the price of few weeks inconvenience I can stop spending time on text editor configuration and/or figuring out on how to install it.

I used #vim and later on neovim fo the period 1998-2023, even before using Linux. I switched to vim in MS-DOS from text editor called #QEDIT :-)

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Jarkko Sakkinen

Does Rust #Linux already have bindings for network drivers? I’m thinking of making #lowRISC Ethernet driver because the one provided by OpenHW Group is a corpse. It is like made for v5.7 and since not updated. This is the one that is used in #CVA6.

#rustlang

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