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authorJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>2016-11-03 17:57:52 -0600
committerJonathan Corbet <corbet@lwn.net>2016-11-07 18:56:42 -0700
commit799a545bb9383c6185ad27063adca03d28ee1823 (patch)
tree99cd895961ab157bd817989f53d60f2f57a1d190 /Documentation/security/tpm
parent9e355ba76455d6d44f5cf888eee820ae9a06b3ec (diff)
tpm: move documentation under Documentation/security
In order too make Documentation root directory cleaner move the tpm directory under Documentation/security. Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation/security/tpm')
-rw-r--r--Documentation/security/tpm/index.rst7
-rw-r--r--Documentation/security/tpm/tpm_vtpm_proxy.rst50
-rw-r--r--Documentation/security/tpm/xen-tpmfront.txt113
3 files changed, 170 insertions, 0 deletions
diff --git a/Documentation/security/tpm/index.rst b/Documentation/security/tpm/index.rst
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index 000000000000..af77a7bbb070
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+++ b/Documentation/security/tpm/index.rst
@@ -0,0 +1,7 @@
+=====================================
+Trusted Platform Module documentation
+=====================================
+
+.. toctree::
+
+ tpm_vtpm_proxy
diff --git a/Documentation/security/tpm/tpm_vtpm_proxy.rst b/Documentation/security/tpm/tpm_vtpm_proxy.rst
new file mode 100644
index 000000000000..ea08e76b17f5
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+=============================================
+Virtual TPM Proxy Driver for Linux Containers
+=============================================
+
+| Authors:
+| Stefan Berger <stefanb@linux.vnet.ibm.com>
+
+This document describes the virtual Trusted Platform Module (vTPM)
+proxy device driver for Linux containers.
+
+Introduction
+============
+
+The goal of this work is to provide TPM functionality to each Linux
+container. This allows programs to interact with a TPM in a container
+the same way they interact with a TPM on the physical system. Each
+container gets its own unique, emulated, software TPM.
+
+Design
+======
+
+To make an emulated software TPM available to each container, the container
+management stack needs to create a device pair consisting of a client TPM
+character device ``/dev/tpmX`` (with X=0,1,2...) and a 'server side' file
+descriptor. The former is moved into the container by creating a character
+device with the appropriate major and minor numbers while the file descriptor
+is passed to the TPM emulator. Software inside the container can then send
+TPM commands using the character device and the emulator will receive the
+commands via the file descriptor and use it for sending back responses.
+
+To support this, the virtual TPM proxy driver provides a device ``/dev/vtpmx``
+that is used to create device pairs using an ioctl. The ioctl takes as
+an input flags for configuring the device. The flags for example indicate
+whether TPM 1.2 or TPM 2 functionality is supported by the TPM emulator.
+The result of the ioctl are the file descriptor for the 'server side'
+as well as the major and minor numbers of the character device that was created.
+Besides that the number of the TPM character device is returned. If for
+example ``/dev/tpm10`` was created, the number (``dev_num``) 10 is returned.
+
+Once the device has been created, the driver will immediately try to talk
+to the TPM. All commands from the driver can be read from the file descriptor
+returned by the ioctl. The commands should be responded to immediately.
+
+UAPI
+====
+
+.. kernel-doc:: include/uapi/linux/vtpm_proxy.h
+
+.. kernel-doc:: drivers/char/tpm/tpm_vtpm_proxy.c
+ :functions: vtpmx_ioc_new_dev
diff --git a/Documentation/security/tpm/xen-tpmfront.txt b/Documentation/security/tpm/xen-tpmfront.txt
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index 000000000000..69346de87ff3
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+Virtual TPM interface for Xen
+
+Authors: Matthew Fioravante (JHUAPL), Daniel De Graaf (NSA)
+
+This document describes the virtual Trusted Platform Module (vTPM) subsystem for
+Xen. The reader is assumed to have familiarity with building and installing Xen,
+Linux, and a basic understanding of the TPM and vTPM concepts.
+
+INTRODUCTION
+
+The goal of this work is to provide a TPM functionality to a virtual guest
+operating system (in Xen terms, a DomU). This allows programs to interact with
+a TPM in a virtual system the same way they interact with a TPM on the physical
+system. Each guest gets its own unique, emulated, software TPM. However, each
+of the vTPM's secrets (Keys, NVRAM, etc) are managed by a vTPM Manager domain,
+which seals the secrets to the Physical TPM. If the process of creating each of
+these domains (manager, vTPM, and guest) is trusted, the vTPM subsystem extends
+the chain of trust rooted in the hardware TPM to virtual machines in Xen. Each
+major component of vTPM is implemented as a separate domain, providing secure
+separation guaranteed by the hypervisor. The vTPM domains are implemented in
+mini-os to reduce memory and processor overhead.
+
+This mini-os vTPM subsystem was built on top of the previous vTPM work done by
+IBM and Intel corporation.
+
+
+DESIGN OVERVIEW
+---------------
+
+The architecture of vTPM is described below:
+
++------------------+
+| Linux DomU | ...
+| | ^ |
+| v | |
+| xen-tpmfront |
++------------------+
+ | ^
+ v |
++------------------+
+| mini-os/tpmback |
+| | ^ |
+| v | |
+| vtpm-stubdom | ...
+| | ^ |
+| v | |
+| mini-os/tpmfront |
++------------------+
+ | ^
+ v |
++------------------+
+| mini-os/tpmback |
+| | ^ |
+| v | |
+| vtpmmgr-stubdom |
+| | ^ |
+| v | |
+| mini-os/tpm_tis |
++------------------+
+ | ^
+ v |
++------------------+
+| Hardware TPM |
++------------------+
+
+ * Linux DomU: The Linux based guest that wants to use a vTPM. There may be
+ more than one of these.
+
+ * xen-tpmfront.ko: Linux kernel virtual TPM frontend driver. This driver
+ provides vTPM access to a Linux-based DomU.
+
+ * mini-os/tpmback: Mini-os TPM backend driver. The Linux frontend driver
+ connects to this backend driver to facilitate communications
+ between the Linux DomU and its vTPM. This driver is also
+ used by vtpmmgr-stubdom to communicate with vtpm-stubdom.
+
+ * vtpm-stubdom: A mini-os stub domain that implements a vTPM. There is a
+ one to one mapping between running vtpm-stubdom instances and
+ logical vtpms on the system. The vTPM Platform Configuration
+ Registers (PCRs) are normally all initialized to zero.
+
+ * mini-os/tpmfront: Mini-os TPM frontend driver. The vTPM mini-os domain
+ vtpm-stubdom uses this driver to communicate with
+ vtpmmgr-stubdom. This driver is also used in mini-os
+ domains such as pv-grub that talk to the vTPM domain.
+
+ * vtpmmgr-stubdom: A mini-os domain that implements the vTPM manager. There is
+ only one vTPM manager and it should be running during the
+ entire lifetime of the machine. This domain regulates
+ access to the physical TPM on the system and secures the
+ persistent state of each vTPM.
+
+ * mini-os/tpm_tis: Mini-os TPM version 1.2 TPM Interface Specification (TIS)
+ driver. This driver used by vtpmmgr-stubdom to talk directly to
+ the hardware TPM. Communication is facilitated by mapping
+ hardware memory pages into vtpmmgr-stubdom.
+
+ * Hardware TPM: The physical TPM that is soldered onto the motherboard.
+
+
+INTEGRATION WITH XEN
+--------------------
+
+Support for the vTPM driver was added in Xen using the libxl toolstack in Xen
+4.3. See the Xen documentation (docs/misc/vtpm.txt) for details on setting up
+the vTPM and vTPM Manager stub domains. Once the stub domains are running, a
+vTPM device is set up in the same manner as a disk or network device in the
+domain's configuration file.
+
+In order to use features such as IMA that require a TPM to be loaded prior to
+the initrd, the xen-tpmfront driver must be compiled in to the kernel. If not
+using such features, the driver can be compiled as a module and will be loaded
+as usual.