OpenSSL TLS using tpm2-pkcs11 doesn't work on newer versions
by Ignacio Jaureguiberry
I was trying to make wpa_supplicant use a tpm2-pkcs11 stored private key to authenticate against a RADIUS server, I mentioned about it on this discussion: https://lists.01.org/hyperkitty/list/tpm2@lists.01.org/message/AYUBCAFCCX...
With some fixes on tpm2-pkcs11, TLS is working and there is an integration test for that here: https://github.com/tpm2-software/tpm2-pkcs11/blob/master/test/integration...
I wasn't able to reproduce this on Ubuntu 18, and noted that the test cases ran on top of an Ubuntu 16.04 image. I tried Ubuntu 16.04 and TLS works as in the integration test. I also checked that using latest version of wpa_supplicant, it does work with tpm2-pkcs11 and creates an EAP-TLS connection using the TPM.
I've debugged a bit in both OS versions and found that openssl is calling pkey_rsa_sign with different padding modes: RSA_PKCS1_PADDING in Ubuntu 16, and RSA_PKCS1_PSS_PADDING in Ubuntu 18. The consequence is that in tpm2-pkcs11, sign_init is being called using CKM_RSA_PKCS as mechanism on Ubuntu 16, but in Ubuntu 18 it is being called with CKM_RSA_X_509, which is not supported.
I think I have to file a bug to OpenSSL, but I don't know too much about the PKCS11 specs to support the claims. I'd appreciate any help to file a decent issue. Also, any workaround is welcome, as replacing OpenSSL in any distribution is very hard given all the software that depends on it.
2 years, 1 month
Made an ZFS root pool auto-unlock, please give review of method
by Garrett Fields
Back in the end of July, I wrote a message on this discussion list titled
"PCR Policy enforcement when using nvram". In that, I asked for a way to
have both a PCR check AND a password lock an nvram range (not an OR). I
really appreciated everyone's help, especially William Roberts, who gave
some sample code of using a session to accomplish this goal.
Now that Ubuntu has updated its repositories for the upcoming 20.04 LTS
release and included TPM-tools v4.x, I figured it was time to take another
look.
My goal is to provide a method to auto-unlock a ZFS encrypted root
filesystem. Currently, ZFS allows for unlocking via a prompt or file
containing a raw, hex, or passphrase values. The mechanisms are already
inplace to prompt on startup.
So far I have just done a proof of concept. It probably loads of bad code
and tons of polish needed:
https://github.com/ghfields/zfs/compare/master...ghfields:tpm2-autounlock
I forked the zfs project, expanded the its initramfs hooks to include the
required tpm2-tools binaries, and added another stanza to init script's
decrypting section. I also created a pair of scripts that configures the
system and tests readback.
The nvram index and the PCRs used are stored/read from the zfs filesystem
properties. I used the filesytem's GUID as the required password as
another check to verify the NVRAM range was intended for that filesystem.
I also intend to issue an nvreadlock to prevent snooping once the key is
used.
I'd be interested in a critique of the method overall I expect there ways
to make this more secure. With enough effort, one could issue a
break=premount on the kernel line and manually extract the password from
the TPM. Any way to tighten that up?
I'm a total novice at TPM in general, but am completely open to advise and
guidance.
Thanks,
Garrett Fields
2 years, 2 months
[RELEASE] tpm2-tools: version 4.1.1
by Roberts, William C
Hello,
I would like to announce the newest stable tools release of version 4.1.1 with the following changes:
4.1.1 - 2020-01-21
* tpm2\_certify: Fix output of attestation data including size field. Now outputs just bytes.
* tpm2\_certifycreation: Fix tool to match manpage where the code had the -C and -c options reversed.
* tpm2\_gettime: Fix output of attestation data including size field. Now outputs just bytes.
* tpm2\_nvcertify: Fix output of attestation data including size field. Now outputs just bytes.
* tpm2\_nvreadpublic: add name hash output.
* tpm2\_import: Support object policies when importing raw key material.
* Fix overflow in pcrs.h where sizeof() was used instead of ARRAY\_LEN().
* build:
- Fix compilation issue: lib/tpm2\_hash.c:17:19: note: 'left' was declared here.
* man:
- Fix manpage examples that have "sha" instead of "sha1"
- tpm2\_shutdown manpage was missing, add it to build.
- Fix manpage example for tpm2\_createak's tpm2\_evictcontrol example.
https://github.com/tpm2-software/tpm2-tools/releases/tag/4.1.1
Thanks,
Bill
2 years, 3 months
Key Certification
by Steffen Schwebel
Hello again,
so I played around with tpm2 tools some more.
I managed to get TLS-EAP networking working with keys stored inside the
crypto chip
Now I would like to prove that the secret keys used are really stored
inside.
If I understand it correctly, I should be able to just sign keys stored
inside the TPM with the AIK I created in a previous step.
so, tpm2_load && tpm2_certify ?
except there seems to be no way to load the keys I created with
tpm2tss-genkey, right?
regards,
Steffen
--
Steffen Schwebel
Mail: s.schwebel(a)uvensys.de
uvensys GmbH
2 years, 3 months
Rust wrapper for TSS ESAPI
by Ionut Mihalcea
Hello all!
As part of some TPM integration work that we’ve been doing, we required access to the Enhanced System API from the Rust language, so we decided to create a wrapper crate and make it available on crates.io. This week we managed to upstream v1 of the crate and its accompanying documentation:
* https://crates.io/crates/tss-esapi
* https://docs.rs/tss-esapi
The crate exposes:
* Raw FFI bindings to the TSS 2.0 ESYS layer
* A low-level abstraction of the bindings which mainly works as a convenience layer, hiding uses of `unsafe` code from the client and making more use of Rusty types.
* A high-level abstraction layer which allows for easy creation and usage of RSA keys for signing and verifying, closer to a proper Rusty development experience.
The last two are by no means complete (in terms of API coverage), focusing on RSA key generation/importing/exporting and signing/verifying with them.
We would be grateful for any feedback, comments, contributions or ideas for what other utilities/abstractions would be most useful!
Thanks,
Ionut
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2 years, 4 months
