How to use TPM2 tool in Linux

TPM2 tool on Linux

https://github.com/intel/tpm2-tools/wiki/How-to-use-tpm2-tools

The tpm2.0-tools manual seems too confusing for people new to TPM 2.0 related areas. This HOW-TO article helps people get to know the basic usage of the tools (v1.1.0) provided by this project, and so be confident to continue using it.

First of all, let's look at some self-contained tools.

• To list values for all available pcrs:

$ tpm2_pcrlist

• To list info about existing NV indices:

$ tpm2_nvlist

• To list info about existing persistent objects:

$ tpm2_listpersistent

• To get a 20 bytes random number into file random.out:

$ tpm2_getrandom -s 20 -o random.out

• To caculate the SHA1 hash value of file data.in and output into hash.out

$ tpm2_hash -H n -g 0x0004 -I data.in -o hash.out -t tk.out

Then, let's understand a word 'ownership' before continuing. TPM ownership means the authorization to do things need authentication first. So taking ownership on a TPM means setting authentication secrets into a TPM so that the ownership can be authenticated later via proving the knowledge of the existing authentication secrets.

• To take ownership with "ownerpass" as owner password, "endorsepass" as endorsement password, "lockpass" as lockout password:

$ tpm2_takeownership -o ownerpass -e endorsepass -l lockpass

• To change ownership passwords to new ones:

$ tpm2_takeownership -o ownerpassnew -e endorsepassnew -l lockpassnew -O ownerpass -E endorsepass -L lockpass

• To set ownership passwords to NULL:

$ tpm2_takeownership -O ownerpassnew -E endorsepassnew -L lockpassnew

• To clear ownership(owner related resources will be released, but can only work while lockout auth is NULL or lockout password is known):

$ tpm2_takeownership -c [-L lockpass]

Most tools can run with or without taking ownership, if not taking ownership, skip corresponding parameter when writing command line. Next up, command lines will be given in both cases for each tools.

• Define NV index with index number 0x1500001, size 32 bytes, attribute word 0x2000A and owner autherization:

Ownership not taken:

$ tpm2_nvdefine -x 0x1500001 -a 0x40000001 -s 32 -t 0x2000A

Ownership taken:

$ tpm2_nvdefine -x 0x1500001 -a 0x40000001 -s 32 -t 0x2000A -P ownerpass

• Write content from file nv.data into NV index 0x1500001, using owner password as authentication

Ownership not taken:

$ tpm2_nvwrite -x 0x1500001 -a 0x40000001 -f nv.data

Ownership taken:

$ tpm2_nvwrite -x 0x1500001 -a 0x40000001 -f nv.data -P ownerpass

• Read 32 bytes content from NV index 0x1500001, start from offset 0, using owner password as authentication

Ownership not taken:

$ tpm2_nvread -x 0x1500001 -a 0x40000001 -s 32 -o 0

Ownership taken:

$ tpm2_nvread -x 0x1500001 -a 0x40000001 -s 32 -o 0 -P ownerpass

• Release NV index 0x1500001, using owner password as authentication

Ownership not taken:

$ tpm2_nvrelease -x 0x1500001 -a 0x40000001

Ownership taken:

$ tpm2_nvrelease -x 0x1500001 -a 0x40000001 -P ownerpass

• Create a Primary Object in endorsement hierarchy, with objectpass as the object password, with RSA keys & SHA256 name hash algorithm, with object context saved in file po.ctx.

Ownership not taken:

$ tpm2_createprimary -A e -K objectpass -g 0x000b -G 0x0001 -C po.ctx

Ownership taken:

$ tpm2_createprimary -A e -K objectpass -g 0x000b -G 0x0001 -C po.ctx -P endorsepass

• Create a RSA key under the previous primary key, with subobjectpass as the object password, with SHA256 name hash algorithm, with public portion saved in key.pub and private portion saved in key.priv

Parent doesn't have password:

$ tpm2_create -c po.ctx -K subobjectpass -g 0x000b -G 0x0001 -o key.pub -O key.priv

Parent has password:

$ tpm2_create -c po.ctx -P objectpass -K subobjectpass -g 0x000b -G 0x0001 -o key.pub -O key.priv

• Load the created RSA key

Parent doesn't have password:

$ tpm2_load -c po.ctx -u key.pub -r key.priv -n key.name -C obj.ctx

Parent has password:

$ tpm2_load -c po.ctx -P objectpass -u key.pub -r key.priv -n key.name -C obj.ctx

• Encrypt with RSA key:

$ tpm2_rsaencrypt -c obj.ctx -I data.in -o data.encrypted

• Decrypt with RSA key:

Key doesn't have password:

$ tpm2_rsadecrypt -c obj.ctx -I data.encrypted -o data.out

Key has password:

$ tpm2_rsadecrypt -c obj.ctx -P subobjectpass -I data.encrypted -o data.out

• Sign on data with RSA key, using SHA256 as hash algorithm:

Key doesn't have password:

$ tpm2_sign -c obj.ctx -g 0x000b -m msg.in -s sig.out

Key has password:

$ tpm2_sign -c obj.ctx -P subobjectpass -g 0x000b -m msg.in -s sig.out

• Verify signature with RSA key:

$ tpm2_verifysignature -c obj.ctx -g 0x000b -m msg.in -s sig.out -t tk.sig

TPM Support in Redhat Ubuntu

Is Trusted Platform Module (TPM) supported by Red Hat?

Environment

• Red Hat Enterprise Linux

Issue

• What is the current status of RHEL interfacing with the TPM?
• Are you currently tracking the development of the trusted GRUB boot loader developed by the Trusted Computing Group?
• Is this product intended to be integrated with the standard Red Hat delivery?
• Is the use of Trusted GRUB supported by Red Hat as part of its standard product delivery?
• What are the current plans for Red Hat Enterprise Linux to support a Trusted Network Connect?
• Does RHEL support TPM 2.0 devices?

Resolution

With Red Hat Enterprise Linux 7, Red Hat ships the tpm-tools package that can talk to the Trusted Platform Module (TPM v.1)

TPM (v1 only) is also now available in RHEL 6.9 as a Technology Preview feature.

Red Hat Enterprise Linux 7.3 completes the kernel level driver support for Trusted Platform Module version 2.0 (TPM 2.0) compliant devices.
In order to access and use the TPM 2.0 hardware you need userspace utilities not currently shipped with RHEL. Requests to add those utilities are currently being reviewed by product management for inclusion into a future RHEL 7 minor release.

Until that time, customers wishing to utilize TPM 2 devices will need the following Unsupported software:

https://github.com/01org/tpm2.0-tools
https://github.com/01org/TPM2.0-TSS

At the time of this writing, Red Hat does not ship the boot loader ("Trusted GRUB") that would be required as part of the chain of trust to establish full TPM integration. No components in RHEL utilize the TPM device to encrypt user data by default.

Red Hat does ship tboot, which enables the use of Intel's TXT technology for trusted boot (this is also Tech Preview on RHEL 6).

TPM 2.0 support by DELL HP Lenovo

TPM 1.2 vs. 2.0 Features

Enterprise Client - Wiki

TPM 1.2 versus TPM 2.0 - Cryptographic Support

The table of encryption algorithms below provides a summary; for a more comprehensive list of TPM algorithms, please reference the TCG Algorithm Registry. The list of mandatory algorithms for TPM 2.0 in a PC is defined in the latest PC Client Platform TPM Profile.

 

Algorithm Type	Algorithm Name	TPM 1.2	TPM 2.0
Asymmetric	RSA 1024	Yes	Optional
	RSA 2048	Yes	Yes
	ECC P256	No	Yes
	ECC BN256	No	Yes
Symmetric	AES 128	Optional	Yes
	AES 256	Optional	Optional
Hash	SHA-1	Yes	Yes
	SHA-2 256	No	Yes
HMAC	SHA-1	Yes	Yes
	SHA-2 256	No	Yes

 

TPM 1.2 versus TPM 2.0 - Behavior Differences

TPM 1.2 supports a single "owner" authorization, with an RSA 2048b Endorsement Key (EK) for signing/attestation and a single RSA 2048b Storage Root Key (SRK) for encryption. This means a single user or entity ("owner") has control over both the signing/attestation and encryption functions of the TPM. In general, the SRK serves as the parent for any keys created in TPM 1.2. TPM 1.2 was specified as an opt-in device (see this TCG article for more information regarding the meaning of "opt-in" as it applies to TPM).

TPM 2.0 has the same functionality represented by the EK for signing/attestation and SRK for encryption as in 1.2, but the control is split into two different hierarchies in 2.0, the Endorsement Hierarchy (EH) and the Storage Hierarchy (SH). In addition to the EH and SH, TPM 2.0 also contains a Platform Hierarchy (PH) for maintenance functions, and a Null Hierarchy. Each hierarchy has its own unique "owner" for authorization. Because of this, TPM 2.0 supports 4 authorizations which would be analogous to the single TPM 1.2 "owner".  

In TPM 2.0, the new Platform Hierarchy is intended to be used by platform manufacturers. The Storage and Endorsement hierarchies, and the Null hierarchy will be used by OS's and OS-present applications. TPM 2.0 has been specified in a way that makes discovery and management less cumbersome than 1.2. TPM 2.0 has the capability to support RSA and ECC algorithms for Endorsement Keys and SRK's.

TPM 1.2 vs. 2.0 - Supported Applications and Features:

Feature or Application	TPM 1.2	TPM 2.0
DDP|ST - OTP client	Yes	No*
DDP|Encryption	Yes	Yes
Intel® Trusted Execution Technology ™	Yes	Yes
Microsoft Bitlocker™	Yes	Yes
Microsoft Virtual Smart Card	Yes	Yes
Microsoft Credential Guard™	Yes	Yes
Microsoft Passport™	Yes	Yes
TCG Measured Boot	Yes	Yes
UEFI Secure Boot	Yes	Yes
Microsoft Device Guard ™	Yes	Yes

 

Note: * DDP | ST works on a system configured with TPM 2.0 but does not utilize the TPM 2.0 at this time.  

 

How is Discrete TPM 2.0 different from a firmware TPM (fTPM)?

A firmware-based TPM (fTPM) is a TPM that operates using the resources and context of a multi-function/feature compute device (such as an SoC, CPU, or other similar compute environment).

A discrete TPM is implemented as an isolated, separate function/feature chip, with all necessary compute resources contained within the discrete physical chip package. A discrete TPM has full control of dedicated internal resources (such as volatile memory, non-volatile memory, and cryptographic logic), and it is the only function accessing and utilizing those resources.

A firmware based TPM does not have its own dedicated storage.  It relies on OS and platform services to provide it access to storage within the platform.  One of the implications of not having dedicated storage involves the presence of an Endorsement Key (EK) certificate.  Discrete TPM devices can be delivered by the TPM manufacturer to the platform manufacturer with an EK certificate installed in the TPM storage for the TPM Endorsement Key.  This is not possible with a firmware TPM.  Firmware TPM vendors make certificates available to end users through manufacturer specific process.  To acquire the EK certificate for a system, platform owners need to contact the chipset/CPU vendor for that platform. 

Additionally, a TCG Certified discrete TPM is required to meet compliance and security requirements including hardening of the chip and its internal resources similar to smart cards. TCG compliance verifies the TPM correctly implements the TCG specifications. The hardening required by TCG certification allows a Certified discrete TPM to protect itself against more complicated physical attacks.

OS Support matrix:

OS Vendor Support

OS	TPM 1.2	TPM 2.0
Windows 7	Yes	No (1)
Windows 8	Yes	Yes (2)
Windows 8.1	Yes	Yes (2)
Windows 10	Yes	Yes
RHEL	Yes	Yes (3)(4)
Ubuntu	Yes	Yes (3)(5)

1. Windows 7 64bit with SP configured in UEFI + CSM boot mode can support TPM 2.0, supported on some platforms
2. Windows 8 launched with support for TPM 2.0, but only supports SHA-1
3. Requires Linux upstream kernel version 4.4 or newer. Linux distribution vendors may choose to backport support to older kernels.
4. RHEL 7.3 and later have basic kernel support. RHEL 7.4 has a tech preview of the userspace tools.
5. Supported on Ubuntu 16.04 and later.

 

Dell Commercial Platform OS Support

OS	TPM 1.2	TPM 2.0
Windows 7	Yes	No
Windows 8	Yes	No (5)
Windows 8.1	Yes	No (5)
Windows 10	Yes	Yes (6)
RHEL	No (7)	Yes (8)
Ubuntu 14.04	No (7)	No
Ubuntu 16.04	No (7)	Yes (9)

5. Dell supports TPM 2.0 with Windows 8 and 8.1 on a limited number of Tablets and Detachable PC's that support Microsoft Connected Standby.

6. TPM 2.0 support available on all Commercial platforms in Spring 2016, and the factory default TPM mode on Windows 10 is TPM 2.0.

7. TPM 1.2 is not officially support by Dell with Linux except on select IoT platforms.

8. Requires RHEL 7.3 or later. User may need to manually change the TPM mode from 1.2 to 2.0.

9. Dell has collaborated with Canonical on TPM 2.0 support on client systems that will ship with TPM 2.0. This requires that Ubuntu 16.04 ships with the system.

 

Dell Platform Support for TPM 2.0

This information has been moved.  See http://en.community.dell.com/techcenter/enterprise-client/w/wiki/12265.dell-tpm-platform-support .