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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen master] docs: move vtpm from misc to man
commit 1854013b0134ece4be45e0ea6d3ee57ba70fbe0f
Author: Cédric Bosdonnat <cbosdonnat@xxxxxxxx>
AuthorDate: Fri Dec 9 15:49:54 2016 +0100
Commit: Wei Liu <wei.liu2@xxxxxxxxxx>
CommitDate: Mon Jan 9 11:05:28 2017 +0000
docs: move vtpm from misc to man
vtpm.txt is referenced in xl.cfg man page. Convert it to pod,
move it to the man folder and update the reference. The man page
is named xen-vtmp to avoid any potential conflict with other
VTPM documentation.
Signed-off-by: Cédric Bosdonnat <cbosdonnat@xxxxxxxx>
Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
docs/INDEX | 1 -
docs/man/xen-vtpm.pod.7 | 377 +++++++++++++++++++++++++++++++++++++++++++++++
docs/man/xl.cfg.pod.5.in | 3 +-
docs/misc/vtpm.txt | 355 --------------------------------------------
4 files changed, 378 insertions(+), 358 deletions(-)
diff --git a/docs/INDEX b/docs/INDEX
index 101d43c..66cc82b 100644
--- a/docs/INDEX
+++ b/docs/INDEX
@@ -18,7 +18,6 @@ misc/xenstore-paths Xenstore path documentation
misc/distro_mapping Distro Directory Layouts
misc/dump-core-format Xen Core Dump Format
misc/vtd VT-d HOWTO
-misc/vtpm Virtual TPM
misc/xen-error-handling Xen Error Handling
misc/xenpaging Xen Paging
misc/xsm-flask XSM/FLASK Configuration
diff --git a/docs/man/xen-vtpm.pod.7 b/docs/man/xen-vtpm.pod.7
new file mode 100644
index 0000000..8de67f4
--- /dev/null
+++ b/docs/man/xen-vtpm.pod.7
@@ -0,0 +1,377 @@
+Copyright (c) 2010-2012 United States Government, as represented by
+the Secretary of Defense. All rights reserved.
+November 12 2012
+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.
+
+=head1 INTRODUCTION
+
+The goal of this work is to provide a TPM functionality to a virtual guest
+operating system (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.
+
+=head1 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 |
+ +------------------+
+
+=over 4
+
+=item Linux DomU
+
+The Linux based guest that wants to use a vTPM. There many be
+more than one of these.
+
+=item xen-tpmfront.ko
+
+Linux kernel virtual TPM frontend driver. This driver
+provides vTPM access to a para-virtualized Linux based DomU.
+
+=item 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.
+
+=item 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 all initialized to zero.
+
+=item 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 could also be used separately to
+implement a mini-os domain that wishes to use a vTPM of
+its own.
+
+=item 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.
+
+=item 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.
+
+=item Hardware TPM
+
+The physical TPM that is soldered onto the motherboard.
+
+=back
+
+=head1 INSTALLATION
+
+=head2 Prerequisites:
+
+You must have an x86 machine with a TPM on the motherboard. The only extra
+software requirement for compiling vTPM is cmake. You must use libxl to manage
+domains with vTPMs; 'xm' is deprecated and does not support vTPMs.
+
+=head2 Compiling the Xen tree:
+
+Compile and install the Xen tree as usual; be sure that the vTPM domains are
+enabled when you run configure.
+
+=head2 Compiling the LINUX dom0 kernel:
+
+Because the TPM manager uses direct access to the physical TPM, it may
interfere
+with access to the TPM by dom0. The simplest solution for this is to prevent
+dom0 from accessing the physical TPM by compiling the kernel without a driver
or
+blacklisting the module. If dom0 needs a TPM but does not need to use it
during
+the boot process (i.e. it is not using IMA), a virtual TPM can be attached to
+dom0 after the system is booted.
+
+Access to the physical TPM may be required in order to manage the NVRAM or to
+perform other advanced operations where the vTPM is insufficient. In order to
+prevent interference, the TPM Manager and dom0 should use different values for
+the TPM's locality; since Linux always uses locality 0, using locality 2 for
the
+TPM Manager is recommended. If both Linux and the TPM Manager attempt to
access
+the TPM at the same time, the TPM device will return a busy status; some
+applications will consider this a fatal error instead of retrying the command
at
+a later time. If a vTPM gets an error when loading its key, it will currently
+generate a fresh vTPM image (with a new EK, SRK, and blank NVRAM).
+
+
+=head2 Compiling the LINUX domU kernel:
+
+The domU kernel used by domains with vtpms must include the xen-tpmfront.ko
+driver. It can be built directly into the kernel or as a module; however, some
+features such as IMA require the TPM to be built in to the kernel.
+
+ CONFIG_TCG_TPM=y
+ CONFIG_TCG_XEN=y
+
+=head1 VTPM MANAGER SETUP
+
+=head2 Manager disk image setup:
+
+The vTPM Manager requires a disk image to store its encrypted data. The image
+does not require a filesystem and can live anywhere on the host disk. The image
+is not large; the Xen 4.5 vtpmmgr is limited to using the first 2MB of the
image
+but can support more than 20,000 vTPMs.
+
+=head2 Manager config file:
+
+The vTPM Manager domain (vtpmmgr-stubdom) must be started like any other Xen
+virtual machine and requires a config file. The manager requires a disk image
+for storage and permission to access the hardware memory pages for the TPM. The
+disk must be presented as "hda", and the TPM memory pages are passed using the
+iomem configuration parameter. The TPM TIS uses 5 pages of IO memory (one per
+locality) that start at physical address 0xfed40000. By default, the TPM
manager
+uses locality 0 (so only the page at 0xfed40 is needed); this can be changed on
+the domain's command line. For full functionality in deep quotes, using
+locality 2 is required to manipulate PCR 20-22.
+
+=head2 Starting and stopping the manager:
+
+The vTPM manager should be started at boot; you may wish to create an init
+script to do this. If a domain builder is used, the TPM Manager should be
+started by the domain builder to minimize the trusted computing base for the
+vTPM manager's secrets.
+
+Once initialization is complete you should see the following:
+
+ INFO[VTPM]: Waiting for commands from vTPM's:
+
+The TPM Manager does not respond to shutdown requests; use the destroy command
+to shut it down.
+
+=head1 VTPM AND LINUX PVM SETUP
+
+=head2 vTPM disk image setup:
+
+The vTPM requires a disk image to store its persistent data (RSA keys, NVRAM,
+etc). The image does not require a filesystem. The image does not need to be
+large; 2 Mb should be sufficient.
+
+=head2 vTPM config file:
+
+The vTPM domain requires a configuration file like any other domain. The vTPM
+requires a disk image for storage and a TPM frontend driver to communicate with
+the manager. You are required to generate a uuid for this vtpm, which is
+specified on the C<vtpm=> line that describes its connection to the vTPM
Manager.
+The uuidgen application may be used to generate a uuid, or one from the output
+of the C<manage-vtpmmgr.pl vtpm-add> command may be used to create a vTPM
+belonging to a specific group.
+
+If you wish to clear the vTPM data you can either recreate the disk image or
+change the uuid.
+
+=head2 Linux Guest config file:
+
+The Linux guest config file needs to be modified to include the Linux tpmfront
+driver. Add the following line:
+
+ vtpm=["backend=domu-vtpm"]
+
+Currently only Linux guests are supported (PV or HVM with PV drivers).
+
+While attaching a vTPM after a guest is booted (using xl vtpm-attach) is
+supported, the attached vTPM will not have a record of the boot of the attached
+guest. Furthermore, if the vTPM has been freshly created, a malicious guest
+could then extend any values into PCRs, potentially forging its boot
+configuration. Attaching a vTPM to a running domain should only be used for
+trusted domains or when measurements have already been sent to the vTPM from
+another source.
+
+=head2 Using the vTPM in the guest:
+
+If xen-tpmfront was compiled as a module, it must be loaded it in the guest.
+
+ # modprobe xen-tpmfront
+
+After the Linux domain boots and the xen-tpmfront driver is loaded, you should
+see the following on the vtpm console:
+
+ Info: VTPM attached to Frontend X/Y
+
+You can quickly test the vTPM by using the sysfs interface:
+
+ # cat /sys/devices/vtpm-0/pubek
+ # cat /sys/devices/vtpm-0/pcrs
+
+If you have trousers and tpm_tools installed on the guest, the tpm_version
+command should return the following:
+
+The version command should return the following:
+
+ TPM 1.2 Version Info:
+ Chip Version: 1.2.0.7
+ Spec Level: 2
+ Errata Revision: 1
+ TPM Vendor ID: ETHZ
+ TPM Version: 01010000
+ Manufacturer Info: 4554485a
+
+You should also see the command being sent to the vtpm console as well as the
+vtpm saving its state. You should see the vtpm key being encrypted and stored
on
+the vtpmmgr console.
+
+You may wish to write a script to start your vtpm and guest together and to
+destroy the vtpm when the guest shuts down.
+
+=head1 INTEGRATION WITH PV-GRUB
+
+The vTPM currently starts up with all PCRs set to their default values (all
+zeros for the lower 16). This means that any decisions about the
+trustworthiness of the created domain must be made based on the environment
that
+created the vTPM and the domU; for example, a system that only constructs
images
+using a trusted configuration and guest kernel be able to provide guarantees
+about the guests and any measurements done that kernel (such as the IMA TCB
+log). Guests wishing to use a custom kernel in such a secure environment are
+often started using the pv-grub bootloader as the kernel, which then can load
+the untrusted kernel without needing to parse an untrusted filesystem and
kernel
+in dom0. If the pv-grub stub domain succeeds in connecting to a vTPM, it will
+extend the hash of the kernel that it boots into PCR #4, and will extend the
+command line and initrd into PCR #5 before booting so that a domU booted in
this
+way can attest to its early boot state.
+
+=head1 MORE INFORMATION
+
+See <xen-vtpmmgr(7)> for more details about how the manager domain works, how
to use
+it, and its command line parameters.
+
+=head1 VTPM DOMAIN OPERATION
+
+The vtpm-stubdom is a mini-OS domain that emulates a TPM for the guest OS to
+use. It is a small wrapper around the Berlios TPM emulator version 0.7.4.
+Commands are passed from the linux guest via the mini-os TPM backend driver.
+vTPM data is encrypted and stored via a disk image provided to the virtual
+machine. The key used to encrypt the data along with a hash of the vTPM's data
+is sent to the vTPM manager for secure storage and later retrieval. The vTPM
+domain communicates with the manager using a mini-os tpm front/back device
pair.
+
+=head1 VTPM DOMAIN COMMAND LINE ARGUMENTS
+
+Command line arguments are passed to the domain via the 'extra' parameter in
the
+VM config file. Each parameter is separated by white space. For example:
+
+ extra="foo=bar baz"
+
+=head2 List of Arguments:
+
+=over 4
+
+=item B<loglevel>=<LOG>
+
+Controls the amount of logging printed to the console.
+The possible values for <LOG> are:
+
+=over 4
+
+=item * error
+
+=item * info (default)
+
+=item * debug
+
+=back
+
+=item B<clear>
+
+Start the Berlios emulator in "clear" mode. (default)
+
+=item B<save>
+
+Start the Berlios emulator in "save" mode.
+
+=item B<deactivated>
+
+Start the Berlios emulator in "deactivated" mode.
+See the Berlios TPM emulator documentation for details
+about the startup mode. For all normal use, always use clear
+which is the default. You should not need to specify any of these.
+
+=item B<maintcmds>=<1|0>
+
+Enable to disable the TPM maintenance commands.
+These commands are used by tpm manufacturers and thus
+open a security hole. They are disabled by default.
+
+=item B<hwinitpcr>=<PCRSPEC>
+
+Initialize the virtual Platform Configuration Registers
+(PCRs) with PCR values from the hardware TPM. Each pcr specified by
+<PCRSPEC> will be initialized with the value of that same PCR in TPM
+once at startup. By default all PCRs are zero initialized.
+Possible values of <PCRSPEC> are:
+
+=over
+
+=item * all: copy all pcrs
+
+=item * none: copy no pcrs (default)
+
+=item * <N>: copy pcr n
+
+=item * <X-Y>: copy pcrs x to y (inclusive)
+
+=back
+
+These can also be combined by comma separation, for example:
+C<hwinitpcrs=5,12-16> will copy pcrs 5, 12, 13, 14, 15, and 16.
+
+=back
+
+=head1 REFERENCES
+
+Berlios TPM Emulator: L<http://tpm-emulator.berlios.de/>
diff --git a/docs/man/xl.cfg.pod.5.in b/docs/man/xl.cfg.pod.5.in
index fc2faac..766bf4d 100644
--- a/docs/man/xl.cfg.pod.5.in
+++ b/docs/man/xl.cfg.pod.5.in
@@ -491,8 +491,7 @@ L<xl-network-configuration(5)>.
=item B<vtpm=[ "VTPM_SPEC_STRING", "VTPM_SPEC_STRING", ...]>
Specifies the virtual trusted platform module to be
-provided to the guest. Please see F<docs/misc/vtpm.txt>
-for more details.
+provided to the guest. Please see L<xen-vtpm(7)> for more details.
Each B<VTPM_SPEC_STRING> is a comma-separated list of C<KEY=VALUE>
settings, from the following list:
diff --git a/docs/misc/vtpm.txt b/docs/misc/vtpm.txt
deleted file mode 100644
index 1887d40..0000000
--- a/docs/misc/vtpm.txt
+++ /dev/null
@@ -1,355 +0,0 @@
-Copyright (c) 2010-2012 United States Government, as represented by
-the Secretary of Defense. All rights reserved.
-November 12 2012
-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 (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 many be
- more than one of these.
-
- * xen-tpmfront.ko: Linux kernel virtual TPM frontend driver. This driver
- provides vTPM access to a para-virtualized 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 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 could also be used
separately to
- implement a mini-os domain that wishes to use a vTPM of
- its own.
-
- * 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.
-
-------------------------------
-INSTALLATION
-------------------------------
-
-Prerequisites:
---------------
-You must have an x86 machine with a TPM on the motherboard. The only extra
-software requirement for compiling vTPM is cmake. You must use libxl to manage
-domains with vTPMs; 'xm' is deprecated and does not support vTPMs.
-
-Compiling the Xen tree:
------------------------
-
-Compile and install the Xen tree as usual; be sure that the vTPM domains are
-enabled when you run configure.
-
-Compiling the LINUX dom0 kernel:
---------------------------------
-
-Because the TPM manager uses direct access to the physical TPM, it may
interfere
-with access to the TPM by dom0. The simplest solution for this is to prevent
-dom0 from accessing the physical TPM by compiling the kernel without a driver
or
-blacklisting the module. If dom0 needs a TPM but does not need to use it
during
-the boot process (i.e. it is not using IMA), a virtual TPM can be attached to
-dom0 after the system is booted.
-
-Access to the physical TPM may be required in order to manage the NVRAM or to
-perform other advanced operations where the vTPM is insufficient. In order to
-prevent interference, the TPM Manager and dom0 should use different values for
-the TPM's locality; since Linux always uses locality 0, using locality 2 for
the
-TPM Manager is recommended. If both Linux and the TPM Manager attempt to
access
-the TPM at the same time, the TPM device will return a busy status; some
-applications will consider this a fatal error instead of retrying the command
at
-a later time. If a vTPM gets an error when loading its key, it will currently
-generate a fresh vTPM image (with a new EK, SRK, and blank NVRAM).
-
-
-Compiling the LINUX domU kernel:
---------------------------------
-
-The domU kernel used by domains with vtpms must include the xen-tpmfront.ko
-driver. It can be built directly into the kernel or as a module; however, some
-features such as IMA require the TPM to be built in to the kernel.
-
-CONFIG_TCG_TPM=y
-CONFIG_TCG_XEN=y
-
-------------------------------
-VTPM MANAGER SETUP
-------------------------------
-
-Manager disk image setup:
--------------------------
-
-The vTPM Manager requires a disk image to store its encrypted data. The image
-does not require a filesystem and can live anywhere on the host disk. The image
-is not large; the Xen 4.5 vtpmmgr is limited to using the first 2MB of the
image
-but can support more than 20,000 vTPMs.
-
-Manager config file:
---------------------
-
-The vTPM Manager domain (vtpmmgr-stubdom) must be started like any other Xen
-virtual machine and requires a config file. The manager requires a disk image
-for storage and permission to access the hardware memory pages for the TPM. The
-disk must be presented as "hda", and the TPM memory pages are passed using the
-iomem configuration parameter. The TPM TIS uses 5 pages of IO memory (one per
-locality) that start at physical address 0xfed40000. By default, the TPM
manager
-uses locality 0 (so only the page at 0xfed40 is needed); this can be changed on
-the domain's command line. For full functionality in deep quotes, using
-locality 2 is required to manipulate PCR 20-22.
-
-Starting and stopping the manager:
-----------------------------------
-
-The vTPM manager should be started at boot; you may wish to create an init
-script to do this. If a domain builder is used, the TPM Manager should be
-started by the domain builder to minimize the trusted computing base for the
-vTPM manager's secrets.
-
-Once initialization is complete you should see the following:
-INFO[VTPM]: Waiting for commands from vTPM's:
-
-The TPM Manager does not respond to shutdown requests; use the destroy command
-to shut it down.
-
-------------------------------
-VTPM AND LINUX PVM SETUP
-------------------------------
-
-vTPM disk image setup:
-----------------------
-
-The vTPM requires a disk image to store its persistent data (RSA keys, NVRAM,
-etc). The image does not require a filesystem. The image does not need to be
-large; 2 Mb should be sufficient.
-
-vTPM config file:
------------------
-
-The vTPM domain requires a configuration file like any other domain. The vTPM
-requires a disk image for storage and a TPM frontend driver to communicate with
-the manager. You are required to generate a uuid for this vtpm, which is
-specified on the "vtpm=" line that describes its connection to the vTPM
Manager.
-The uuidgen application may be used to generate a uuid, or one from the output
-of the "manage-vtpmmgr.pl vtpm-add" command may be used to create a vTPM
-belonging to a specific group.
-
-If you wish to clear the vTPM data you can either recreate the disk image or
-change the uuid.
-
-Linux Guest config file:
-------------------------
-
-The Linux guest config file needs to be modified to include the Linux tpmfront
-driver. Add the following line:
-
-vtpm=["backend=domu-vtpm"]
-
-Currently only Linux guests are supported (PV or HVM with PV drivers).
-
-While attaching a vTPM after a guest is booted (using xl vtpm-attach) is
-supported, the attached vTPM will not have a record of the boot of the attached
-guest. Furthermore, if the vTPM has been freshly created, a malicious guest
-could then extend any values into PCRs, potentially forging its boot
-configuration. Attaching a vTPM to a running domain should only be used for
-trusted domains or when measurements have already been sent to the vTPM from
-another source.
-
-Using the vTPM in the guest:
-----------------------------
-
-If xen-tpmfront was compiled as a module, it must be loaded it in the guest.
-
-# modprobe xen-tpmfront
-
-After the Linux domain boots and the xen-tpmfront driver is loaded, you should
-see the following on the vtpm console:
-
-Info: VTPM attached to Frontend X/Y
-
-You can quickly test the vTPM by using the sysfs interface:
-
-# cat /sys/devices/vtpm-0/pubek
-# cat /sys/devices/vtpm-0/pcrs
-
-If you have trousers and tpm_tools installed on the guest, the tpm_version
-command should return the following:
-
-The version command should return the following:
- TPM 1.2 Version Info:
- Chip Version: 1.2.0.7
- Spec Level: 2
- Errata Revision: 1
- TPM Vendor ID: ETHZ
- TPM Version: 01010000
- Manufacturer Info: 4554485a
-
-You should also see the command being sent to the vtpm console as well as the
-vtpm saving its state. You should see the vtpm key being encrypted and stored
on
-the vtpmmgr console.
-
-You may wish to write a script to start your vtpm and guest together and to
-destroy the vtpm when the guest shuts down.
-
-------------------------------
-INTEGRATION WITH PV-GRUB
-------------------------------
-
-The vTPM currently starts up with all PCRs set to their default values (all
-zeros for the lower 16). This means that any decisions about the
-trustworthiness of the created domain must be made based on the environment
that
-created the vTPM and the domU; for example, a system that only constructs
images
-using a trusted configuration and guest kernel be able to provide guarantees
-about the guests and any measurements done that kernel (such as the IMA TCB
-log). Guests wishing to use a custom kernel in such a secure environment are
-often started using the pv-grub bootloader as the kernel, which then can load
-the untrusted kernel without needing to parse an untrusted filesystem and
kernel
-in dom0. If the pv-grub stub domain succeeds in connecting to a vTPM, it will
-extend the hash of the kernel that it boots into PCR #4, and will extend the
-command line and initrd into PCR #5 before booting so that a domU booted in
this
-way can attest to its early boot state.
-
-------------------------------
-MORE INFORMATION
-------------------------------
-
-See vtpmmgr.txt for more details about how the manager domain works, how to use
-it, and its command line parameters.
-
-------------------------------
-VTPM DOMAIN OPERATION
-------------------------------
-
-The vtpm-stubdom is a mini-OS domain that emulates a TPM for the guest OS to
-use. It is a small wrapper around the Berlios TPM emulator version 0.7.4.
-Commands are passed from the linux guest via the mini-os TPM backend driver.
-vTPM data is encrypted and stored via a disk image provided to the virtual
-machine. The key used to encrypt the data along with a hash of the vTPM's data
-is sent to the vTPM manager for secure storage and later retrieval. The vTPM
-domain communicates with the manager using a mini-os tpm front/back device
pair.
-
-------------------------------------
-VTPM DOMAIN COMMAND LINE ARGUMENTS
-------------------------------------
-
-Command line arguments are passed to the domain via the 'extra' parameter in
the
-VM config file. Each parameter is separated by white space. For example:
-
-extra="foo=bar baz"
-
-List of Arguments:
-------------------
-
-loglevel=<LOG>: Controls the amount of logging printed to the console.
- The possible values for <LOG> are:
- error
- info (default)
- debug
-
-clear: Start the Berlios emulator in "clear" mode. (default)
-
-save: Start the Berlios emulator in "save" mode.
-
-deactivated: Start the Berlios emulator in "deactivated" mode.
- See the Berlios TPM emulator documentation for details
- about the startup mode. For all normal use, always use clear
- which is the default. You should not need to specify any of these.
-
-maintcmds=<1|0>: Enable to disable the TPM maintenance commands.
- These commands are used by tpm manufacturers and thus
- open a security hole. They are disabled by default.
-
-hwinitpcr=<PCRSPEC>: Initialize the virtual Platform Configuration Registers
- (PCRs) with PCR values from the hardware TPM. Each pcr specified by
- <PCRSPEC> will be initialized with the value of that same PCR in TPM
- once at startup. By default all PCRs are zero initialized.
- Value values of <PCRSPEC> are:
- all: copy all pcrs
- none: copy no pcrs (default)
- <N>: copy pcr n
- <X-Y>: copy pcrs x to y (inclusive)
-
- These can also be combined by comma separation, for example:
- hwinitpcrs=5,12-16
- will copy pcrs 5, 12, 13, 14, 15, and 16.
-
-------------------------------
-REFERENCES
-------------------------------
-
-Berlios TPM Emulator:
-http://tpm-emulator.berlios.de/
--
generated by git-patchbot for /home/xen/git/xen.git#master
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