@lindi2 @pid_eins After TPM2 asymmetric keys has landed we could conclude that the kernel side is in some sense "feature complete" as far as TPM2 is concerned.

There might be some additional stuff in EFI upcoming *possibly*. I'm thinking UKI here but since I'm not that familiar with it, I don't have exact picture what it might possibly require from kernel. But at least as far as runtime features are concerned, looking solid.

@lindi2 @pid_eins good news, Linus pulled my PR’s in queue:https://social.kernel.org/notice/AhrCE3Z7RqcBa1p1Hc. So the changes are now in the mainline.

For security research: HMAC pipe is for the kernel clients we do not want to layer /dev/tpm0. It can be done just as well in the user space (and should be when required).

I.e. right now for trusted keys, and soon’ish for asymmetric keys (feature requried for x.509 certificates [1]). You can also grep the call sites by:

$ git grep "tpm2_start_auth_session(.*);"
drivers/char/tpm/tpm2-cmd.c:	rc = tpm2_start_auth_session(chip);
drivers/char/tpm/tpm2-cmd.c:	err = tpm2_start_auth_session(chip);
include/linux/tpm.h:int tpm2_start_auth_session(struct tpm_chip *chip);
security/keys/trusted-keys/trusted_tpm2.c:	rc = tpm2_start_auth_session(chip);
security/keys/trusted-keys/trusted_tpm2.c:	rc = tpm2_start_auth_session(chip);
security/keys/trusted-keys/trusted_tpm2.c:	rc = tpm2_start_auth_session(chip);

x.509 part will be 6.11 feature.

[1] https://datatracker.ietf.org/doc/draft-woodhouse-cert-best-practice/ NOTE: a bit out of date, I chatted quickly with David and he is planning to remove TPM 1.2 and DSA keys from the draft.

Finally HMAC encryption for in-kernel TPM clients is going to a release! Has been hanging there for a long time.

LUKS2 and distributions starting to support it motivated me to rewrite the buffering code last Spring because that was my main turn-down in the original patch set, and then James took over and cleaned up the functionality and I reviewed it for few rounds until it was good enough.

With this and TPM2 sealed hard drive encryption there is a somewhat reasonable security model without having to type encryption password to a bootloader prompt (which is tedious). I.e. login and go.

A rare case of security feature also increasing user experience.

#linux #kernel #tpm #luks2

My first trial to split pull request to TPM, trusted keys, keyring parts: all three pull requests taken by pr-tracker-bot :—–O

One more left for asymmetric keys. Cannot believe this, I always screw up with this dance at least first time :-) Really made my Monday!

@grumpygamer [was a fair punishment tho]

@grumpygamer and always one of the floppy disks had a bad sector when you pirated a game from a friend :-(

Classic version control:

@ljs staff has been nice, polite and helpful have to say tho! thanks for not arresting me ;-)

@ljs i've sometimes been in completely wrong areas where i should not even have access just like by plain accident. then the security guard has just said "you should have never even gotten to these ports, how did this happen" (not when arrested, more like when i've went to ask myself where the f*ck i am).

@ljs i know

@sima @josh hmm... just a friendly advice but maybe you should not buy anything from those web stores? :-) i mean for me it sounds more like that the web browser recommends you not buy anything given the faulty security... so it is a feature almost

The City of #Helsinki Education Division #databreach has upto 120000 victims: "the perpetrator has gained access to the usernames and email addresses of all city personnel, as well as the personal IDs and addresses of students, guardians and personnel from the Education Division."

The attacker also gained access to confidential or sensitive records stored on a network share. The beach occurred due to unpatched known vulnerability getting exploited to gain unauthorized access. https://www.hel.fi/en/news/investigation-into-helsinki-education-division-data-breach-proceeds https://www.hel.fi/en/decision-making/data-breach #infosec #cybersecurity

@ljs Chicago airport can be tricky.

Sometimes it feels like every day is a x.509 day tbh... #x509

@signalapp @rjzak what you think

@signalapp Also, e.g. in Finland Signal is the recommended app for journalists. Why leave known loopholes to the implementation? Does not reflect the company's brand at all.

@signalapp Also we had this feature in https://www.enarx.dev/, i.e. it is possible to piggy pack CPU-attestation into x.509 :-) Both the issue and at least one way to fix it has been shown to exist.

@mjg59 also previous work exists where piggy packing CPU attestation into x.509 has been demonstrated. At least Enarx has this feature. So proof-of-concept done I guess.

@mjg59 i don't care about this that much but i'd like if they fixed the privacy issue: https://social.kernel.org/notice/AhqRIM69n1KYN5p5hg. good times to promote this given the board changes...

Let's put this into nutshell.

In Signal, SGX *does not* help the user to secure contact delivery. You have to *believe* that signal.org is trustworthy plain and simple.

In Signal, SGX does only help signal.org to secure contact delivery from 3rd party adversaries.

The marketing has been somewhat misleading with this for number of years although there has not been any actual lies. They are actually claiming only the 2nd clause but at the same time claiming that it would improve users privacy.

Users privacy can be objectively said to be improved only if one can test and measure that this is really the case. Otherwise it is up to you to believe that signal.org is doing the right thing, and not e.g. just emulate the associated opcodes.

I personally believe that they are doing the (morally) right thing, and using legit SGX, but I would feel more convinced if they would also provide hard evidence on the topic, i.e. certificate delivery and verification in the app using Intel's CA.

#signal #sgx #infosec @signalapp