1swtpm-create-tpmca(8) swtpm-create-tpmca(8)
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6 swtpm-create-tpmca - Tool to create a local CA for swtpm_localca
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9 swtpm-create-tpmca [OPTIONS]
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12 swtpm-create-tpmca is a tool to create a TPM 1.2 based CA that can be
13 used by swtpm_localca to sign EK and platform certificates. The CA
14 uses a GnuTLS key to sign certificates. To do this, GnuTLS talks to the
15 TPM 1.2 using the tcsd (TrouSerS) daemon.
16 Since the TPM CA's certificate must be signed by a CA, a root
18 certificate authority will also be created and will sign this
19 certificate. The root CA's private key and certificate will be located
20 in the same directory as the signing key and have the names
21 swtpm-localca-rootca-privkey.pem and swtpm-localca-rootca-cert.pem
22 respectively. The environment variable SWTPM_ROOTCA_PASSWORD can be set
23 for the password of the root CA's private key.
24 Note: This tool is experimental. See the section on known issues below.
26 The following options are supported:
28 --dir dir
30 The directory where the keys will be written to. An existing root
31 CA with the files swtpm-localca-rootca-privkey.pem and
32 swtpm-localca-rootca-cert.pem in this directory will be reused. If
33 either one of these files does not exist, a new root CA will be
34 created.
35 --overwrite
37 Overwrite the contents of the output directory.
38 --register
40 Register the key with TCSD. For the key to be available for
41 signing, the same user that created the TPM CA has to run the
42 swtpm_localca tool later on. If this option is not passed, the
43 private key is written into a file and can be used by others as
44 well.
45 --key-password s
47 The new signing key will get this password.
48 Note: Due to a bug in GnuTLS certtool it may be necessary to use
50 the same password for the signing key as for the SRK.
51 --srk-password s
53 The TPM SRK password.
54 Note: Since GnuTLS tpmtool does not support the 'well known'
56 password of 20 zero bytes, the SRK password must be set.
57 --outfile filename
59 The name of a file where to write the swtpm-localca.conf
60 configuration to.
61 --owner owner
63 The name or uid number of the owner who will own the directory and
64 outfile file. This option only has an effect if this swtpm-create-
65 tpmca is run by the root user.
66 --group group
68 The name or gid number of the group who will own the directory and
69 outfile file. This option only has an effect if this swtpm-create-
70 tpmca is run by the root user.
71 --tss-tcsd-hostname
73 The hostname where tcsd is running on. The default hostname is
74 'localhost'.
75 -tss-tcsd-port
77 The TCP port on which tcsd is listening for messages. The default
78 port is 30003.
79 --tpm2
81 The TPM to use for signing the certificates is a TPM 2 and Intel's
82 TSS stack must be running (tpm2-abrmd) along with its PKCS11
83 module. The TPM 2 PKCS11 module must have been initialized using
84 the tpm2_ptool.
85 The environment variables SWTPM_PKCS11_PIN and SWTPM_PKCS11_SO_PIN
87 should be set to hold the PINs. If SWTPM_PKCS11_PIN is not set then
88 the default PIN 'swtpm-tpmca' will be used. SWTPM_PKCS11_SO_PIN is
89 needed for creating the token and must be explicitly set as an
90 environment variable.
91 --pid pimary-object-id
93 The primary object id that the tpm2_ptool returns upon 'init'.
94 -help, -h, -?
96 Display the help screen and exit.
97
99 The following example creates an intermediate TPM CA and writes the
100 keys into /var/lib/swtpm-localca and the swtpm_localca configuration to
101 /etc/swtpm-localca.conf. It can then be used for signing certificates
102 of newly created swtpm TPMs.
103 If the host's TPM is a TPM 1.2, we need to start the tcsd first and can
105 then create the TPM key and TPM CA certificate:
106 #> sudo systemctl start tcsd
108 #> sudo /usr/share/swtpm/swtpm-create-tpmca \
109 --dir /var/lib/swtpm-localca \
110 --overwrite \
111 --outfile /etc/swtpm-localca.conf \
112 --srk-password password \
113 --key-password password \
114 --group tss
115 statedir = /var/lib/swtpm-localca
116 signingkey = tpmkey:file=/var/lib/swtpm-localca/swtpm-localca-tpmca-privkey.pem
117 issuercert = /var/lib/swtpm-localca/swtpm-localca-tpmca-cert.pem
118 certserial = /var/lib/swtpm-localca/certserial
119 TSS_TCSD_HOSTNAME = localhost
120 TSS_TCSD_PORT = 30003
121 signingkey_password = password
122 parentkey_password = password
123 Alternatively, if the host's TPM is a TPM 2 and Intel's TPM 2 stack is
125 installed, we need to start tpm2-abrmd first and can then create the
126 TPM key and TPM CA certificate:
127 #> sudo systemctl start tpm2-abrmd
129 #> tpm2_ptool init
130 action: Created
131 id: 1 # this is the --pid parameter below
132 #> sudo SWTPM_PKCS11_PIN="mypin 123" SWTPM_PKCS11_SO_PIN=123 /usr/share/swtpm/swtpm-create-tpmca \
133 --dir /var/lib/swtpm-localca \
134 --overwrite \
135 --outfile /etc/swtpm-localca.conf \
136 --group tss \
137 --tpm2 \
138 --pid 1
139 statedir = /var/lib/swtpm-localca
140 signingkey = pkcs11:model=SW%20%20%20TPM\;manufacturer=IBM\;serial=0000000000000000\;token=swtpm-tpmca-1\;id=%31\;object=swtpm-tpmca-key\;type=private
141 issuercert = /var/lib/swtpm-localca/swtpm-localca-tpmca-cert.pem
142 certserial = /var/lib/swtpm-localca/certserial
143 SWTPM_PKCS11_PIN = mypin 123
144 Note: This also works for non-root users by adapting the --dir and
146 --outfile parameters here and below by changing the --dir parameter and
147 adding a --config parameter.
148 To test either one of the above TPM CAs, run the following command:
150 #> swtpm_localca \
152 --type ek --ek x=11,y=13 \
153 --dir /tmp --vmid test --tpm2 \
154 --tpm-spec-family 2.0 --tpm-spec-revision 146 --tpm-spec-level 00 \
155 --tpm-model swtpm --tpm-version 20170101 --tpm-manufacturer IBM
156 The --tpm2 in this command indicates that the TPM for which the
158 certificate is created is a TPM 2.
159
161 The interaction of GnuTLS certtool with the TPM TCSD daemon may cause
162 so many TPM (key) authentication failures that the TPM refuses to
163 accept any more authenticated commands until the TPM's owner sends it
164 the TPM_ORD_ResetLockValue command. The reason for this is that
165 certtool first tries to use 20 zero bytes for the SRK password and only
166 then prompts for and uses the required SRK password. The GnuTLS tpmtool
167 does not support 20 zero bytes for the SRK password, so forces the
168 usage of a 'real' password.
169 The effect of the authentication failures may be that the TPM CA cannot
171 sign certificates since the TPM does not accept authenticated commands.
172
174 swtpm_localca, swtpm-localca.conf, tcsd
175
177 Report bugs to Stefan Berger <stefanb@linux.ibm.com>
178swtpm 2023-08-16 swtpm-create-tpmca(8)