Provided by: swtpm_0.7.3-0ubuntu5.24.04.1_amd64 
NAME
swtpm - TPM Emulator for TPM 1.2 and 2.0
SYNOPSIS
swtpm socket [OPTIONS]
swtpm chardev [OPTIONS]
swtpm cuse [OPTIONS]
DESCRIPTION
swtpm implements a TPM software emulator built on libtpms. It provides access to TPM
functionality over a TCP/IP socket interface or it can listend for commands on a character
device, or create a CUSE (character device in userspace) interface for receiving of TPM
commands.
Unless corresponding command line parameters are used, the swtpm socket version requires
that the environment variable TPM_PORT be set to the TCP/IP port the process is supposed
to listen on for TPM request messages.
Similarly, the environment variable TPM_PATH can be set and contain the name of a
directory where the TPM can store its persistent state into.
The swtpm process can be gracefully terminated by sending a SIGTERM signal to it.
The swtpm cuse version requires root rights to start the TPM.
Options for socket interface
The following options are supported if the socket interface is chosen:
-p|--port <port>
Use the given port rather than using the environment variable TPM_PORT.
-t|--terminate
Terminate the TPM after the client has closed the connection.
--server [type=tcp][,port=<port>[,bindaddr=<address>
[,ifname=<ifname>]]][,fd=<fd>][,disconnect]
Expect TCP connections on the given port; if a port is not provided a file descriptor
must be passed with the fd parameter and the commands are read from this file
descriptor then. If a port is provided the bind address on which to listen for TCP
connections can be provided as well; the default bind address is 127.0.0.1. If a link
local IPv6 address is provided, the name of the interface to bind to must be provided
with ifname.
This parameter enables a persistent connection by default unless the disconnect option
is given. This parameter should be used rather than the -p and --fd options.
--server type=unixio[,path=<path>][,fd=<fd>] [,mode=<0...>][,uid=<uid>][,gid=<gid>]
Expect UnixIO connections on the given path. If no path is provided, a file descriptor
must be passed instead. The mode parameter allows a user to set the file mode bits of
the UnixIO path. The mode bits value must be given as an octal number starting with a
'0'. The default value is 0770. uid and gid set the ownership of the UnixIO socket's
path. This operation requires root privileges.
Options for character device interface
The following options are supported if the chardev interface is chosen:
-c|--chardev <device path>
Use the given device to listen for TPM commands and send response on.
--vtpm-proxy
Create a Linux vTPM proxy device instance and read TPM commands from its backend
device.
Options for the CUSE interface
The following options are supported if the cuse interface is chosen:
-n|--name <NAME>
The TPM will use a device with the given name. A device with the given name will be
created in /dev. This is a mandatory option.
-M|--maj <MAJOR>
Create the device with the given major number.
-m|--min <MINOR>
Create the device with the given minor number.
Options for socket and character device interfaces:
The following options are supported by the socket and character device interfaces:
-f|--fd <fd>
Use the given socket file descriptor or character device file descriptor for receiving
TPM commands and sending responses. For the socket interface, this option
automatically assumes -t.
-d|--daemon
Daemonize the process.
--ctrl type=[unixio|tcp][,path=<path>]
[,port=<port>[,bindaddr=<address>[,ifname=<ifname>]]]
[,fd=<filedescriptor>|clientfd=<filedescriptor>] [,mode=<0...>][,uid=<uid>][,gid=<gid>]
This option adds a control channel to the TPM. The control channel can either use a
UnixIO socket with a given path or filedescriptor or it can use a TCP socket on the
given port or filedescriptor. If a port is provided the bind address on which to
listen for TCP connections can be provided as well; the default bind address is
127.0.0.1. If a link local IPv6 address is provided, the name of the interface to bind
to must be provided with ifname.
The mode parameter allows a user to set the file mode bits of the UnixIO path. The
mode bits value must be given as an octal number starting with a '0'. The default
value is 0770. uid and gid set the ownership of the UnixIO socket's path. This
operation requires root privileges.
The control channel enables out-of-band control of the TPM, such as resetting the TPM.
Options for all interfaces
The following options are support by all interfaces:
--tpmstate dir=<dir>[,mode=<0...>]|backend-uri=<uri>
Use the given path rather than using the environment variable TPM_PATH.
If dir is specified, the TPM state files will be written to the dir with the given
file mode bits. This value must be given as an octal number starting with a '0'. The
default value is 0640.
If backend-uri is specified, the TPM state data will be stored to the URI. Currently
backend-uri=dir://<path_to_dir> and backend-uri=file://<path_to_dir> are available.
For 'dir://', the URI should specify the path to the directory where files are stored.
If path_to_dir starts with a '/' then the path is interpreted as an absolute path,
otherwise it is a path relative to the current directory. For 'file://', the URI
should specify a single file or block device where TPM state will be stored. A
blockdevice must exist already and be big enough to store all state. (since v0.7)
--tpm2
Choose TPM 2 functionality; by default a TPM 1.2 is chosen.
--log [fd=<fd>|file=<path>][,level=<n>] [,prefix=<prefix>][,truncate]
Enable logging to a file given its file descriptor or its path. Use '-' for path to
suppress the logging.
The level parameter allows a user to choose the level of logging. Starting at log
level 5, libtpms debug logging is activated.
All logged lines will be prefixed with prefix. By default no prefix is prepended.
If truncate is passed, the log file will be truncated.
--locality reject-locality-4[,allow-set-locality]
The reject-locality-4 parameter will cause TPM error messages to be returned for
requests to set the TPM into locality 4.
The allow-set-locality parameter allows the swtpm to receive TPM/TPM2_SetLocality
commands. This is parameter is useful if the Linux VTPM proxy driver access is enabled
by file descriptor passing. This option is implied by the --vtpm-proxy option and
therefore need not be explicitly set if this option is passed. In all other cases care
should be taken as to who can send the TPM/TPM2_SetLocality command.
--key file=<keyfile>|fd=<fd> [,format=<hex|binary>][,mode=aes-cbc|aes-256-cbc],
[remove[=true|false]]
Enable encryption of the state files of the TPM. The keyfile must contain an AES key
of supported size; 128 bit (16 bytes) and 256 bit (32 bytes) keys are supported.
The key may be in binary format, in which case the file size must be 16 or 32 bytes.
If the key is in hex format (default), the key may consist of 32 or 64 hex digits
starting with an optional '0x'.
The mode parameter indicates which block chaining mode is to be used. Currently aes-
cbc (aes-128-cbc) and aes-256-cbc are supported. The encrypted data is integrity
protected using encrypt-then-mac.
The remove parameter will attempt to remove the given keyfile once the key has been
read.
--key pwdfile=<passphrase file>|pwdfd=<fd>
[,mode=aes-cbc|aes-256-cbc][remove[=true|false]][,kdf=sha512|pbkdf2]
This variant of the key parameter allows a user to provide a passphrase in a file.
The file is read and a key is derived from it using either a SHA512 hash or PBKDF2. By
default PBKDF2 is used.
--migration-key file=<keyfile>|fd=<fd> [,format=<hex|binary>][,mode=aes-cbc|aes-256-cbc]
[,remove[=true|false]]
The availability of a migration key ensures that the state of the TPM will not be
revealed in unencrypted form when the TPM state blobs are retrieved through the ioctl
interface. The migration key is not used for encrypting TPM state written to files,
this is what the --key parameter is used for.
The migration key and the key used for encrypting the TPM state files may be the same.
While the key for the TPM state files needs to stay with those files it encrypts, the
migration key needs to stay with the TPM state blobs. If for example the state of the
TPM is migrated between hosts in a data center, then the TPM migration key must be
available at all the destinations, so in effect it may have to be a key shared across
all machines in the datacenter. In contrast to that, the key used for encrypting the
TPM state files can be different for each TPM and need only be available on the host
where the TPM state resides.
The migration key enables the encryption of the TPM state blobs. The keyfile must
contain an AES key of supported size; 128 bit (16 bytes) and 256 bit (32 bytes) keys
are supported.
The key may be in binary format, in which case the file size must be 16 or 32 bytes.
If the key is in hex format (default), the key may consist of 32 or 64 hex digits
starting with an optional '0x'.
The mode parameter indicates which block chaining mode is to be used. Currently aes-
cbc (aes-128-cbc) and aes-256-cbc are supported. The encrypted data is integrity
protected using encrypt-then-mac.
The remove parameter will attempt to remove the given keyfile once the key has been
read.
--migration-key pwdfile=<passphrase file>|pwdfd=<fd>
[,mode=aes-cbc|aes-256-cbc][,remove[=true|false]][,pdf=sha512|pbkdf2]
This variant of the key parameter allows a user to provide a passphrase in a file.
The file is read and a key is derived from it using either a SHA512 hash or PBKDF2. By
default PBKDF2 is used.
--pid file=<pidfile>|fd=<filedescriptor>
This options allows a user to set the name of file where the process ID (pid) of the
TPM will be written into. It is also possible to pass a file descriptor to a file that
has been opened for writing.
-r|--runas <owner>
Switch to the given user. This option can only be used when swtpm is started as root.
--seccomp action=none|log|kill (since v0.2)
This option allows a user to select the action to take by the seccomp profile when a
syscall is executed that is not allowed. The default is kill. To disable the seccomp
profile, choose none. The log action logs offending syscalls. The log action is only
available if libseccomp supports logging.
This option is only available on Linux and only if swtpm was compiled with libseccomp
support.
--flags [not-need-init] [,startup-clear|startup-state|startup-deactivated|startup-none]
The not-need-init flag enables the TPM to accept TPM commands right after start
without requiring an INIT to be sent to it through the command channel (see the '-i'
option of swtpm_ioctl).
The startup options cause a TPM_Startup or TPM2_Startup command to automatically be
sent. The startup-deactivated option is only valid for a TPM 1.2. These options imply
not-need-init, except for the startup-none option, which results in no command being
sent.
If --vtpm-proxy is used, startup-clear is automatically chosen but this can be changed
with this option.
--print-capabilities (since v0.2)
Print capabilities that were added to swtpm after version 0.1. The output may contain
the following:
{
"type": "swtpm",
"features": [
"tpm-1.2",
"tpm-2.0",
"cmdarg-seccomp",
"cmdarg-key-fd",
"cmdarg-pwd-fd",
"cmdarg-print-states",
"nvram-backend-dir",
"nvram-backend-file",
"tpm-send-command-header",
"flags-opt-startup",
"rsa-keysize-1024",
"rsa-keysize-2048",
"rsa-keysize-3072"
],
"version": "0.7.0"
}
The version field is available since v0.7.
The meaning of the feature verbs is as follows:
tpm-1.2 (since v0.7)
TPM 1.2 emulation is supported (libtpms is compiled with 1.2 support).
tpm-2.0 (since v0.7)
TPM 2 emulation is supported (libtpms is compiled with 2.0 support).
(the --tpm2 option is supported)
cmdarg-seccomp (since v0.2)
The --seccomp option is supported.
cmdarg-key-fd (since v0.2)
The --key option supports the fd= parameter.
cmdarg-pwd-fd (since v0.2)
The --key option supports the pwdfd= parameter.
cmdarg-print-states (since v0.7)
The --print-states option is supported.
nvram-backend-dir (since v0.7)
The --tpmstate option supports the backend-uri=dir://... parameter.
nvram-backend-file (since v0.7)
The --tpmstate option supports the backend-uri=file://... parameter.
tpm-send-command-header (since v0.2)
The TPM 2 commands may be prefixed by a header that carries a 4-byte command, 1
byte for locality, and 4-byte TPM 2 command length indicator. The TPM 2 will
respond by preprending a 4-byte response indicator and a 4-byte trailer. All data
is sent in big endian format.
flags-opt-startup (since v0.3)
The --flags option supports the startup-... options.
rsa-keysize-2048 (since v0.4)
The TPM 2 supports the shown RSA key sizes. If none of the rsa-keysize verbs is
shown then only RSA 2048 bit keys are supported.
--print-states (since v0.7)
This option allows to print out the TPM 1.2 or TPM 2 state blobs that are currently
stored in a storage backend. This option requires that the storage backend be
specified using the --tpmstate option and if TPM 2 state blobs are supposed to be
shown, the --tpm2 option must be passed.
The following shows the JSON output of this option. It indicates that the 'permall'
and 'volatile' states are available.
{
"type": "swtpm",
"states": [
{
"name": "permall",
"size": 6013
}, {
"name": "volatile",
"size": 1087
}
]
}
-h|--help
Display usage info.
SEE ALSO
swtpm_bios, swtpm_cuse