swtpm/man/man8/swtpm_setup.pod
Stefan Berger e3668c9f26 swtpm_setup: Add support for RSA-4096 keys for EKs
Add support for RSA-4096 kyes for EKs. This requires users to choose the
default-v2 profile because this is the only profile that currently enables
this type of a key.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
2025-05-08 20:49:36 -04:00

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=head1 NAME
swtpm_setup - Swtpm tool to simulate the manufacturing of a TPM 1.2 or 2.0
=head1 SYNOPSIS
B<swtpm_setup [OPTIONS]>
=head1 DESCRIPTION
B<swtpm_setup> is a tool that prepares the initial state for a libtpms-based
TPM.
The following options are supported:
=over 4
=item B<--runas <userid>>
Use this userid to run swtpm_setup as. Only 'root' can use this option.
=item B<--config <file>>
Path to configuration file containing the tool to use for creating
certificates; see also B<swtpm_setup.conf>
If this parameter is not provided, the default configuration file
will be used. The search order for the default configuration file is
as follows. If the environment variable XDG_CONFIG_HOME is set,
${XDG_CONFIG_HOME}/swtpm_setup.conf will be used if available, otherwise if
the environment variable HOME is set, ${HOME}/.config/swtpm_setup.conf
will be used if available. If none of the previous ones are available, /etc/swtpm_setup.conf
will be used.
=item B<--tpm-state <dir>> or B<--tpmstate <dir>>
Path where the TPM's state will be written to; this is a mandatory argument.
Prefix with dir:// to use directory backend, or file:// to use linear file.
=item B<--tpm "path-to-executable socket">
Path to the TPM executable; this is an optional argument and by default the
swtpm executable found in the PATH will be used. To use 'swtpm' with this
parameter it is necessary to pass along the 'socket' parameter. To emulate
the default behavior this option could be used as follows:
=over 2
--tpm "$(type -P swtpm) socket"
=back
=item B<--tpm2>
Do setup on a TPM 2; by default a TPM 1.2 is setup.
=item B<--createek>
Create an endorsement key (EK).
=item B<--allow-signing>
Create an EK that can sign. This option requires --tpm2.
This option will create a non-standard EK. When re-creating the EK, TPM 2
tools have to use the EK Template that is written at an NV index corresponding
to the created EK (e.g., NV index 0x01c00004 for RS 2048 EK). Otherwise the
tool-created EK will not correspond to the actual key being used or the
modulus shown in the EK certificate.
Note that the TCG specification "EK Credential Profile For TPM Family 2.0; Level 0"
suggests in its section on "EK Usage" that "the Endorsement Key can be a
created as a decryption or signing key." However, some platforms will
not accept an EK as a signing key, or as a signing and encryption key, and
therefore this option should be used very carefully.
=item B<--decryption>
Create an EK that can be used for key encipherment. This is the default
unless --allow-signing is passed. This option requires --tpm2.
=item B<--ecc>
Create elliptic curve crypto (ECC) keys; by default RSA keys are generated.
=item B<--take-ownership>
Take ownership; this option implies --createek. This option is only available for TPM 1.2.
=item B<--ownerpass <password>>
Provide custom owner password; default is 'ooo'. This option is only available for TPM 1.2.
=item B<--owner-well-known>
Use a password of all zeros (20 bytes of zeros) as the owner password.
This option is only available for TPM 1.2.
=item B<--srkpass <password>>
Provide custom SRK password; default is 'sss'. This option is only available for TPM 1.2.
=item B<--srk-well-known>
Use a password of all zeros (20 bytes of zeros) as the SRK password.
This option is only available for TPM 1.2.
=item B<--create-ek-cert>
Create an EK certificate; this implies --createek.
=item B<--create-platform-cert>
Create a platform certificate; this implies --create-ek-cert.
=item B<--lock-nvram>
Lock NVRAM access to all NVRAM locations that were written to.
=item B<--display>
At the end display as much info as possible about the configuration
of the TPM.
=item B<--logfile <logfile>>
The logfile to log to. By default logging goes to stdout and stderr.
=item B<--keyfile <keyfile>>
The key file contains an ASCII hex key consisting of 32 hex digits with an
optional leading '0x'. This is the key to be used by the TPM emulator
for encrypting the state of the TPM.
=item B<--keyfile-fd <file descriptor>>
Like B<--keyfile> but the key will be read from the file descriptor.
=item B<--pwdfile <passphrase file>>
The passphrase file contains a passphrase from which the TPM emulator
will derive the encryption key from and use the key for encrypting the TPM
state.
=item B<--pwdfile-fd <file descriptor>>
Like B<--pwdfile> but the passphrase will be read from the file descriptor.
=item B<--ciper <cipher>>
The cipher may be either aes-cbc or aes-128-cbc for 128 bit AES encryption,
or aes-256-cbc for 256 bit AES encryption. The same cipher must be used
on the I<swtpm> command line later on.
=item B<--overwrite>
Overwrite existing TPM state. All previous state will be erased.
If this option is not given and an existing state file is found, an error
code is returned.
=item B<--not-overwrite>
Do not overwrite existing TPM state. If existing TPM state is found, the
program ends without an error.
=item B<--vmid <VM ID>>
Optional VM ID that can be used to keep track of certificates issued
for VMs (or containers). This parameter will be passed through to the tool
used for creating the certificates and may be required by that tool.
=item B<--pcr-banks <PCR banks>>
Optional comma-separated list of PCR banks to activate. Providing '-'
allows a user to skip the selection and activates all PCR banks.
If this option is not provided, the I<swtpm_setup.conf> configuration
file will be consulted for the active_pcr_banks entry. If no such
entry is found then the default set of PCR banks will be activated.
The default set of PCR banks can be determined using the I<--help>
option.
=item B<--swtpm_ioctl <executable>>
Pass the path to the swtpm_ioctl executable. By default the swtpm_ioctl
in the PATH is used.
=item B<--tcsd-system-ps-file <file>>
This option is deprecated and has no effect (since v0.4).
=item B<--rsa-keysize <keysize>> (since v0.4)
This option allows to pass the size of a TPM 2 RSA EK key, such as 2048,
3072, or 4096. The supported keysizes for a TPM 2 can be queried for using
the I<--print-capabilities> option. The default size is 2048 bits for
both TPM 1.2 and TPM 2. If 'max' is passed, the largest possible key
size is used. It may be necessary to choose an approriate profile that
supports this key size, such as 'default-v2' for RSA-4096 keys.
=item B<--reconfigure> (since v0.7)
This option allows the reconfiguration of the active PCR banks of a
TPM 2 using the I<--pcr-banks> option.
=item B<--profile <json-profile>> (since v0.10)
Configure a TPM 2 with the given profile. Example profiles look
like this:
{"Name": "null"}
{"Name": "default-v1"}
{
"Name": "custom",
"Algorithms":"rsa,rsa-min-size=1024,tdes-min-size=128,hmac,aes,\
aes-min-size=128,mgf1,keyedhash,xor,sha256,sha384,\
sha512,null,rsassa,rsaes,rsapss,oaep,ecdsa,ecdh,ecdaa,\
sm2,ecschnorr,ecmqv,kdf1-sp800-56a,kdf2,kdf1-sp800-108,\
ecc,ecc-min-size=192,ecc-nist,ecc-bn,symcipher,camellia,\
camellia-min-size=128,cmac,ctr,ofb,cbc,cfb,ecb"
}
The JSON profile must contain the 'name' field with a name of a profile
supported by libtpms. Only the 'custom' profile, or profiles whose name
starts with 'custom:', are modifiable and may contain Algorithms, Commands, or
Attributes fields with user selections. Unknown fields in the JSON profile
will be ignored. For further information see the swtpm man page.
=item B<--profile-name <profile filename| built-in profile name> (since v0.10)
Configure a TPM 2 with a profile loaded from either one of the following
locations in the shown order, unless qualified by a prefix:
=over 2
=item * local profiles dir specified in swtpm_setup.conf as
'local_profiles_dir'; to force loading the profile from this directory,
prefix the name with 'local:'
=item * distro profile dir, which is typically /usr/share/swtpm/profiles; to
force loading the profile from this directory prefix the name with 'distro:'
=item * instantiate a libtpms built-in profile; to force a built-in profile
prefix the name with 'builtin:'
=back
All profiles loaded from the above mentioned directories require that the
file is available under the given name with '.json' appended.
Use the I<--print-profiles> and I<--tpm2> options to display all available
profiles.
=item B<--profile-file <file>> (since v0.10)
Configure a TPM 2 with a profile from a file.
=item B<--profile-file-fd <fd>> (since v0.10)
Configure a TPM 2 with a profile read from a file descriptor.
=item B<--profile-remove-disabled check|fips-host> (since v0.10)
When this option is passed then swtpm will remove algorithms from the given
profile that OpenSSL cannot use when FIPS mode is enabled on the host. If
the I<check> parameter is given then algorithms are tested before they are
removed while the I<fips-host> parameter forces the removal of all potentially
disabled algorithms without testing them.
This option only works if the 'custom' profile is referenced by passing
I<--profile '{"Name":"custom:test"}'> for example.
This option passes the I<remove-disable> option parameter as part of the
I<--profile> option to swtpm. For further information see the man page for
I<swtpm>.
=item B<--print-profiles> (since v0.10)
Print all profiles found in the local and disto profiles directories and
display the built-in ones. All profiles stored in files must have the .json
extension. The names in the displayed JSON will show the name under
which these profiles can be loaded with the I<--profile-name> option,
i.e., they will show their filename without the .json extension. Therefore,
a profile with filename myprofile.json will show the I<Name> 'myprofile'.
The author of the profile may want to set the I<Name> in the profile's JSON
to 'custom:myprofile'.
=item B<--print-capabilities> (since v0.2)
Print capabilities that were added to swtpm_setup after version 0.1.
The output may contain the following:
{
"type": "swtpm_setup",
"features": [
"tpm-1.2",
"tpm-2.0",
"cmdarg-keyfile-fd",
"cmdarg-pwdfile-fd",
"tpm12-not-need-root",
"cmdarg-write-ek-cert-files",
"cmdarg-create-config-files",
"cmdarg-reconfigure-pcr-banks",
"tpm2-rsa-keysize-2048",
"tpm2-rsa-keysize-3072",
"tpm2-rsa-keysize-4096",
"cmdarg-profile",
"cmdarg-profile-remove-disabled"
],
"version": "0.7.0"
}
The version field is available since v0.7.
The meaning of the feature verbs is as follows:
=over 4
=item B<cmdarg-key-fd> (since v0.2)
The I<--keyfile-fd> option is supported.
=item B<cmdarg-pwd-fd> (since v0.2)
The I<--pwdfile-fd> option is supported.
=item B<cmdarg-write-ek-cert-files> (since v0.7)
The I<--write-ek-cert-files> option is supported.
=item B<cmdarg-create-config-files> (since v0.7)
The I<--create-config-files> option is supported.
=item B<cmdarg-reconfigure-pcr-banks> (since v0.7)
The I<--reconfigure> option is supported and allows the reconfiguration of
the active PCR banks.
=item B<tpm2-rsa-keysize-2048, ...> (since v0.4)
The shown RSA key sizes are supported for a TPM 2's EK key. If none of the
tpm2-rsa-keysize verbs is shown then only RSA 2048 bit keys are supported.
=item B<tpm12-not-need-root> (since v0.4)
This option implies that any user can setup a TPM 1.2. Previously only root
or the 'tss' user, depending on configuration and availability of this account,
could do that.
=item B<tpm-1.2> (since v0.7)
TPM 1.2 setup is supported (libtpms is compiled with TPM 1.2 support).
=item B<tpm-2.0> (since v0.7)
TPM 2 setup is supported (libtpms is compiled with TPM 2 support).
=item B<cmdarg-profile> (since v0.10)
The I<--profile>, I<profile-file>, and I<--profile-file-fd> options are
supported.
=item B<cmdarg-profile-remove-disabled> (since v0.10)
The I<--profile-remove-disabled> option is supported.
=back
=item B<--write-ek-cert-files <directory>> (since v0.7)
This option causes endorsement key (EK) files to be written into the provided
directory. The files contain the DER-formatted EKs that were written into the
NVRAM locations of the TPM 1.2 or TPM 2. The EK files have the filename pattern
of ek-<key type>.crt. Example for filenames are ek-rsa2048.crt, ek-rsa3072.crt,
and ek-secp384r1.crt.
The keys that are written for a TPM 2 may change over time as the default
strength of the EK keys changes. This means that one should look for all
files with the above filename pattern when looking for the EKs.
=item B<--create-config-files [[overwrite][,root][,skip-if-exist]]> (since v0.7)
This option allows a user to create configuration files for swtpm_setup and
swtpm-localca under the $XDG_CONFIG_HOME or $HOME/.config directories.
The configuration files will not be created if any one of them already
exists and in this case the program will report the first file it finds
and exit with an error code.
The meaning of the options is as follows:
=over 4
=item B<overwrite>
Overwrite any existing configuration files.
=item B<root>
Create the configuration files even under the root account. These
configuration files may then shadow any other existing configuration files,
such as /etc/swtpm-localca.conf for example.
=item B<skip-if-exist>
Do nothing if any one of the configuration files that would be created already
exists. The program will exit without error code.
=back
Note: The case when a user is part of the group that is allowed to access
the default configuration files' paths is currently not handled. On many
systems this may be the case when a user is part of the 'tss' group. In
this case it is recommended that the user replace the swtpm-localca.conf
created with this command with a symbolic link to /etc/swtpm-localca.conf.
=item B<--help, -h>
Display the help screen
=back
=head1 EXAMPLE USAGE
To simulate manufacturing of a TPM, one would typically run the following command:
#> sudo swtpm_setup --tpmstate /tmp/mytpm1/ \
--create-ek-cert --create-platform-cert --lock-nvram
Note: since v0.4 TPM 1.2 setup does not require root rights anymore.
Any user can also simulate the manufacturing of a TPM using the
swtpm_localca utility. The following example assumes that the user has
set the environment variable XDG_CONFIG_HOME as follows (using bash for
example):
export XDG_CONFIG_HOME=~/.config
Note: The XDG_CONFIG_HOME variable is part of the XDG Base Directory
Specification.
The following configuration files need to be created:
~/.config/swtpm_setup.conf:
# Program invoked for creating certificates
create_certs_tool= /usr/share/swtpm/swtpm-localca
create_certs_tool_config = ${XDG_CONFIG_HOME}/swtpm-localca.conf
create_certs_tool_options = ${XDG_CONFIG_HOME}/swtpm-localca.options
~/.config/swtpm-localca.conf:
statedir = ${XDG_CONFIG_HOME}/var/lib/swtpm-localca
signingkey = ${XDG_CONFIG_HOME}/var/lib/swtpm-localca/signkey.pem
issuercert = ${XDG_CONFIG_HOME}/var/lib/swtpm-localca/issuercert.pem
certserial = ${XDG_CONFIG_HOME}/var/lib/swtpm-localca/certserial
~/.config/swtpm-localca.options:
--platform-manufacturer Fedora
--platform-version 2.12
--platform-model QEMU
Note: The tool swtpm-create-user-config-files can be used to create such
files (with different content):
#> /usr/share/swtpm/swtpm-create-user-config-files
Writing /home/stefanb/.config/swtpm_setup.conf.
Writing /home/stefanb/.config/swtpm-localca.conf.
Writing /home/stefanb/.config/swtpm-localca.options.
The following commands now create a TPM 2 with an EK and platform
certificate. The state of the TPM 2 will be stored in the directory
${XDG_CONFIG_HOME}/mytpm1.
#> mkdir -p ${XDG_CONFIG_HOME}/mytpm1
#> swtpm_setup --tpm2 --tpmstate ${XDG_CONFIG_HOME}/mytpm1 \
--create-ek-cert --create-platform-cert --lock-nvram
=head1 SEE ALSO
B<swtpm_setup.conf>
=head1 REPORTING BUGS
Report bugs to Stefan Berger <stefanb@linux.ibm.com>