@Foxboron Kernel has IMHO nice approach for parsing ASN.1 written a long time ago by David Howells but still legit, safe and fast:

1. scripts/asn1_compiler.c: compiles ASN.1 as bytecode with callbacks called “actions” written in C.
2. lib/asn1_decoder.c: there’s a function that takes a blob containing bytecode program for a particular ASN.1 definition and buffer containing der-file. Then the function interprets the whole thing using two arrays: machine[] for opcodes and actions[] for callbacks.

Parsers become quite strict and safe as any instance of parser does not try to parse every possible ASN.1 but fails on anything else than one single particular ASN1 format.

I recently went through ASN.1 crates for Rust with the idea of doing experimental CONFIG_ASN1_RUST flag, but none of the crates I found (looked e.g. every single one from crates.io) was not even near the quality of this elegant approach. Well-designed C can be safer than improperly designed Rust, and this good example of it.

If I did an ASN.1 parser in user space with Go, I’d use the gist of this design even on that.

The project itself could have bunch for ASN.1 files in its repository and the build process would pre-compile the parsers for each one of them. Then based on the OID, the decoder could just pick the right parser from cache indexed by the OID.

Thought to share this because I love the design and have not seen this idea implemented in user space.

I completely forgot I uploaded VistaPro 3.20 (the scenery renderer) to the Internet Archive, where you can run it from your browser. For those sudden urges of wanting to create some landscapes.

https://archive.org/details/vistapro320

Includes the MakePath tool.

Don't forget to take screenshots of your creations! Nothing can be retrieved from the disk the in-browser DOSBox keeps, as far as I know.

(Please be patient with the Archive's speed, they're dealing with persistent DDoS attacks at the moment)

@mort @gregkh s/fuck/hug/ 🌼

@harrysintonen Quite recent RNG. Added to my backlog after looking from Wikipedia the implementation: "FPGA exercise: https://en.wikipedia.org/wiki/Permuted_congruential_generator";. Perfect learning for my low FPGA skills with low-end'ish Lattice FPGA ;-) [but with open source stack, which is rare]. Thx.

Also this will purposely bound to Linux at least for now. E.g. it should be able to interact directly with kernel keyring.

So the first goal would be to make this dump into two commands:

tpm2_createprimary --hierarchy o -G ecc -c owner.txt
tpm2_evictcontrol -c owner.txt 0x81000001
openssl ecparam -name prime256v1 -genkey -noout -out private.pem
tpm2_import -C 0x81000001 -G ecc -i private.pem -u key.pub -r key.priv
tpm2_encodeobject -C 0x81000001 -u key.pub -r key.priv -o key.priv.pem
openssl asn1parse -inform pem -in key.priv.pem -noout -out key.priv.der

The.idea is to make it more like use-case oriented tool rather than one that maps the protocol as “plumbing” commands.

@colinianking One tool that I missed most is the error decoder, which can show the constant name on which I've been unsuccessful with other options ;-) Contributions are welcome but I might relicense the code base as MIT.

While developing asymmetric TPM2 keys, and reviewing TPM bus encryption earlier, I came to realize that both tpm2-tools and ibmtss feel unintuitive.

So I started to seek, if some had ever backed up my old tpm2-scripts, from which kselftest was inherited. I did not have anymore any repo for that one.

With Google I luckily found a backup from the Github profile of @colinianking, so thank you for that. Then I just copied over latest version of just tpm2.py (GPL/BSD dual-licensed file).

Probably will have some incompatibility issues with old scripts and updated main module (less than 10 updates in its total life-time tho) but I will fix them as soon as I need to test anything.

Anyway, a new and to-be-lean TPM2 hacking tool has been initiated: tpm2ctl (there’s no even file of that name yet but definitely will be at some point ;-)).

URL: https://gitlab.com/jarkkojs/tpm2ctl

A plea for more thoughtful comments https://lwn.net/Articles/975597/ #tech #linux

Ever wondered why @torvalds coined the #Linux #kernel's "no regressions" rule? He just explained it again here: https://lore.kernel.org/all/CAHk-=wgtb7y-bEh7tPDvDWru7ZKQ8-KMjZ53Tsk37zsPPdwXbA@mail.gmail.com/

'"[…] I introduced that "no regressions" rule something like two decades ago, because people need to be able to update their kernel without fear of something they relied on suddenly stopping to work. […]"'

Follow the link for context and other statements that did not fit into a toot.

#LinuxKernel #regressions

@ljs @kernellogger @torvalds Yeah, it is more important how you react when by a plain mistake a regression is introduced, than not introducing them at all, i.e. transparency and brutal honesty is the key IMHO :-)

And also, for instance with this fresh bus encryption feature for TPM chips, despite getting only a single performance regression report from a private user so far, I scaled "default y" down to "default X86_64" because that is the only platform where I've been able to test it successfully even with an old Intel Celeron NUC.

I would also emphasize this as a maintainer: even if the new feature is exciting, scale it down *eagerly* before it hits a release. It is always easier scale up later on, than scale down. I tend to label "uncertainty" as a regression despite not having better knowledge rather than "wait and see". I'd label any other behavior as pure ignorance: you knew that shit might hit the fan but did absolutely nothing.

Emailed to TCG:

Forwarded message from Trusted Computing Group on Wed May 29, 2024 at 1:58 PM:
Message Body:
Some views on topic I've written:
- https://social.kernel.org/notice/AiNuw35YY9uOSrhiK0
- https://github.com/wolfSSL/wolfTPM/issues/356
Linux kernel patch set ongoing which made me realize that p256k1 is lacking from your registry:
- https://lore.kernel.org/linux-integrity/20240528210823.28798-1-jarkko@kernel.org/
This really should exist despite not being the most secure ECC given the compatibility to a number o
f open source projects and platforms (not just ETH and BTC). Please read also the above links, the w
rite ups are short and to the point. This would add by factors the importance of TPM2 ecosystem spre
ading to new applications.

--
This e-mail was sent from a contact form on Trusted Computing Group (https://trustedcomputinggroup.o
rg)

On possibility of adding TPM_ECC_SECP_P256_K1 curve to https://trustedcomputinggroup.org/wp-content/uploads/TCG-Algorithm-Registry-Revision-1.34_pub-1.pdf

Unless I overlooked something, which is entirely possible, Linux does not know how to sign even NIST-ECDSA (p256r1). That would make tpm2_key_ecdsa the first module that can do ECDSA signatures at all.

I think after TPM2 RSA/ECDSA work lands to mainline, I'll make software implementation of p256k1 ECDSA verification, and some time later, signing. That way at least TPM2 keys can root a key hierarchy for p256k1 keys to the Linux keyring, despite being just software implementation.

Stefan Berger has done during last 2-3 years a decent ecc_* API so should not be even a huge stretch.

So tpm2_key_ecdsa (if I did not overlook anything, cannot be 100% sure) might even enable ECDSA signing overall for Linux kernel for the first time.

#linux #kernel #keys #keyring

https://curl.se/libcurl/

Connecting to #Ethereum Name Service and similar crazy crypto distributed hellholes is dead easy with C: #libcurl. Also much more transparent than those crazy #Web3-frameworks :-) I don't know what they do in the machinery, so thus do not like them.

Dropped this question also to #wolfSSL: https://github.com/wolfSSL/wolfTPM/issues/356

#Microsoft has invested considerable amount of money on #Ethereum but still nobody has put forward p256k1 to the TCG Algorithm Registry. IMHO, would be somewhat dead obvious thing to do...

https://trustedcomputinggroup.org/resource/tcg-algorithm-registry/

#TPM #blockchain

I wonder if TCG is ever going to add p256k1 to their algorithm repository...

Asymmetric #TPM2 #keys v7:

https://lore.kernel.org/linux-crypto/20240528210823.28798-1-jarkko@kernel.org/T/#mb07f85a8c3f4af388cbc08438e71ac8aea447d85

This is the first version with fully working #ECDSA signing and signature verification with the public key.

Implementation notes:

1. Accepts only sha256 at this point. Can be easily extended later. It is best overall choice for the first version.
2. Does not accept any authentication policy yet. Can be extended later by adding a new parameter to match_table_t param_keys in security/keys/keyctl_pkey.c. E.g. "policy=%s".

I’m pretty happy with this, given that I did it fully during 1.5 week period on my free time and unpaid ;-)

#Linux #kernel #TPM