1tpm2_stirrandom(1) General Commands Manual tpm2_stirrandom(1)
2
6 tpm2_stirrandom(1) - Add “additional information” into TPM RNG state.
7
9 tpm2_stirrandom [OPTIONS] [ARGUMENT]
10
12 tpm2_stirrandom(1) - Inject “additional information” as bytes into TPM
13 entropy Protected Capability pool.
14 “Additional information” can be extracted from file specified as argu‐
16 ment or being read from STDIN if argument is not specified.
17 Up to 128 bytes can be injected at once through standard input to
19 tpm2_stirrandom(1).
20 If input file is larger than 128 bytes, tpm2_stirrandom(1) will fail.
22 Adding data through tpm2_stirrandom(1) will trigger a reseeding of TPM
24 DRBG Protected Capability. It is used when performing any sensitive
25 action on a shielded location such as loading a persistent key or act‐
26 ing on a Protected Capability like updating TPM firmware.
27
29 This command has no option
30 References
33 This collection of options are common to many programs and provide in‐
34 formation that many users may expect.
35 • -h, --help=[man|no-man]: Display the tools manpage. By default, it
37 attempts to invoke the manpager for the tool, however, on failure
38 will output a short tool summary. This is the same behavior if the
39 “man” option argument is specified, however if explicit “man” is re‐
40 quested, the tool will provide errors from man on stderr. If the
41 “no-man” option if specified, or the manpager fails, the short op‐
42 tions will be output to stdout.
43 To successfully use the manpages feature requires the manpages to be
45 installed or on MANPATH, See man(1) for more details.
46 • -v, --version: Display version information for this tool, supported
48 tctis and exit.
49 • -V, --verbose: Increase the information that the tool prints to the
51 console during its execution. When using this option the file and
52 line number are printed.
53 • -Q, --quiet: Silence normal tool output to stdout.
55 • -Z, --enable-errata: Enable the application of errata fixups. Useful
57 if an errata fixup needs to be applied to commands sent to the TPM.
58 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent. in‐
59 formation many users may expect.
60
62 The TCTI or “Transmission Interface” is the communication mechanism
63 with the TPM. TCTIs can be changed for communication with TPMs across
64 different mediums.
65 To control the TCTI, the tools respect:
67 1. The command line option -T or --tcti
69 2. The environment variable: TPM2TOOLS_TCTI.
71 Note: The command line option always overrides the environment vari‐
73 able.
74 The current known TCTIs are:
76 • tabrmd - The resource manager, called tabrmd
78 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
79 abrmd as a tcti name are synonymous.
80 • mssim - Typically used for communicating to the TPM software simula‐
82 tor.
83 • device - Used when talking directly to a TPM device file.
85 • none - Do not initalize a connection with the TPM. Some tools allow
87 for off-tpm options and thus support not using a TCTI. Tools that do
88 not support it will error when attempted to be used without a TCTI
89 connection. Does not support ANY options and MUST BE presented as
90 the exact text of “none”.
91 The arguments to either the command line option or the environment
93 variable are in the form:
94 <tcti-name>:<tcti-option-config>
96 Specifying an empty string for either the <tcti-name> or <tcti-op‐
98 tion-config> results in the default being used for that portion respec‐
99 tively.
100 TCTI Defaults
102 When a TCTI is not specified, the default TCTI is searched for using
103 dlopen(3) semantics. The tools will search for tabrmd, device and
104 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
105 what TCTI will be chosen as the default by using the -v option to print
106 the version information. The “default-tcti” key-value pair will indi‐
107 cate which of the aforementioned TCTIs is the default.
108 Custom TCTIs
110 Any TCTI that implements the dynamic TCTI interface can be loaded. The
111 tools internally use dlopen(3), and the raw tcti-name value is used for
112 the lookup. Thus, this could be a path to the shared library, or a li‐
113 brary name as understood by dlopen(3) semantics.
114
116 This collection of options are used to configure the various known TCTI
117 modules available:
118 • device: For the device TCTI, the TPM character device file for use by
120 the device TCTI can be specified. The default is /dev/tpm0.
121 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI=“de‐
123 vice:/dev/tpm0”
124 • mssim: For the mssim TCTI, the domain name or IP address and port
126 number used by the simulator can be specified. The default are
127 127.0.0.1 and 2321.
128 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
130 TI=“mssim:host=localhost,port=2321”
131 • abrmd: For the abrmd TCTI, the configuration string format is a se‐
133 ries of simple key value pairs separated by a `,' character. Each
134 key and value string are separated by a `=' character.
135 • TCTI abrmd supports two keys:
137 1. `bus_name' : The name of the tabrmd service on the bus (a
139 string).
140 2. `bus_type' : The type of the dbus instance (a string) limited to
142 `session' and `system'.
143 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
145 ample.FooBar:
146 \--tcti=tabrmd:bus_name=com.example.FooBar
148 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
150 sion:
151 \--tcti:bus_type=session
153 NOTE: abrmd and tabrmd are synonymous. the various known TCTI mod‐
155 ules.)
156
158 Inject from stdin using echo
159 echo -n "myrandomdata" | tpm2_stirrandom
160 Inject 64 bytes from stdin using a file
162 dd if=/dev/urandom bs=1 count=64 > myrandom.bin
163 tpm2_stirrandom < ./myrandom.bin
165 Inject bytes from a file and reading up to 128 bytes
167 dd if=/dev/urandom of=./myrandom.bin bs=1 count=42
168 tpm2_stirrandom ./myrandom.bin
170
172 Please be aware that even if the “additional information” added by
173 tpm2_stirrandom(1) can be entropy gathered from other DRBG sources, the
174 TPM has no way of determining if the value has any entropy or not. As
175 a consequence, it will just be considered as “additional input”.
176 The “additional input” is as defined in NIST SP800-90A
178 (https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublica‐
179 tion800-90.pdf)
180
182 Tools can return any of the following codes:
183 • 0 - Success.
185 • 1 - General non-specific error.
187 • 2 - Options handling error.
189 • 3 - Authentication error.
191 • 4 - TCTI related error.
193 • 5 - Non supported scheme. Applicable to tpm2_testparams.
195
197 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
198
200 See the Mailing List (https://lists.01.org/mailman/listinfo/tpm2)
201tpm2-tools tpm2_stirrandom(1)