PKI secrets engine - quick start - intermediate CA setup

In the first Quick Start guide, certificates were issued directly from the root certificate authority. As described in the example, this is not a recommended practice. This guide builds on the previous guide's root certificate authority and creates an intermediate authority using the root authority to sign the intermediate's certificate.

Mount the backend

To add another certificate authority to our OpenBao instance, we have to mount it at a different path.

$ bao secrets enable -path=pki_int pki
Successfully mounted 'pki' at 'pki_int'!

Configure an intermediate CA

$ bao secrets tune -max-lease-ttl=43800h pki_int
Successfully tuned mount 'pki_int'!

That sets the maximum TTL for secrets issued from the mount to 5 years. This value should be less than or equal to the root certificate authority.

Now, we generate our intermediate certificate signing request:

$ bao write pki_int/intermediate/generate/internal common_name="myopenbao.com Intermediate Authority" ttl=43800h
Key Value
csr -----BEGIN CERTIFICATE REQUEST-----
MIICsjCCAZoCAQAwLTErMCkGA1UEAxMibXl2YXVsdC5jb20gSW50ZXJtZWRpYXRl
IEF1dGhvcml0eTCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAJU1Qh8l
BW16WHAu34Fy92FnSy4219WVlKw1xwpKxjd95xH6WcxXozOs6oHFQ9c592bz51F8
KK3FFJYraUrGONI5Cz9qHbzC1mFCmjnXVXCoeNKIzEBG0Y+ehH7MQ1SvDCyvaJPX
ItFXaGf6zENiGsApw3Y3lFr0MjPzZDBH1p4Nq3aA6L2BaxvO5vczdQl5tE2ud/zs
GIdCWnl1ThDEeiX1Ppduos/dx3gaZa9ly3iCuDMKIL9yK5XTBTgKB6ALPApekLQB
kcUFbOuMzjrDSBe9ytu65yICYp26iAPPA8aKTj5cUgscgzEvQS66rSAVG/unrWxb
wbl8b7eQztCmp60CAwEAAaBAMD4GCSqGSIb3DQEJDjExMC8wLQYDVR0RBCYwJIIi
bXl2YXVsdC5jb20gSW50ZXJtZWRpYXRlIEF1dGhvcml0eTANBgkqhkiG9w0BAQsF
AAOCAQEAZA9A1QvTdAd45+Ay55FmKNWnis1zLjbmWNJURUoDei6i6SCJg0YGX1cZ
WkD0ibxPYihSsKRaIUwC2bE8cxZM57OSs7ISUmyPQAT2IHTHvuGK72qlFRBlFOzg
SHEG7gfyKdrALphyF8wM3u4gXhcnY3CdltjabL3YakZqd3Ey4870/0XXeo5c4k7w
/+n9M4xED4TnXYCGfLAlu5WWKSeCvu9mHXnJcLo1MiYjX7KGey/xYYbfxHSPm4ul
tI6Vf59zDRscfNmq37fERD3TiKP0QZNGTSRvnrxrx2RUQGXFywM8l4doG8nS5BxU
2jP20cdv0lJFvHr9663/8B/+F5L6Yw==
-----END CERTIFICATE REQUEST-----

Take the signing request from the intermediate authority and sign it using another certificate authority, in this case the root certificate authority generated in the first example.

$ bao write pki/root/sign-intermediate csr=@pki_int.csr format=pem_bundle ttl=43800h
Key             Value
certificate     -----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
expiration      1669568873
issuing_ca      -----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
serial_number   10:dc:50:0f:b2:88:26:2d:73:13:f8:c4:89:8a:80:1b:55:42:e0:dc

Now set the intermediate certificate authorities signing certificate to the root-signed certificate.

$ bao write pki_int/intermediate/set-signed certificate=@signed_certificate.pem
Success! Data written to: pki_int/intermediate/set-signed

The intermediate certificate authority is now configured and ready to issue certificates.

Set URL configuration

Generated certificates can have the CRL location and the location of the issuing certificate encoded. These values must be set manually, but can be changed at any time.

$ bao write pki_int/config/urls issuing_certificates="http://127.0.0.1:8200/v1/pki_int/ca" crl_distribution_points="http://127.0.0.1:8200/v1/pki_int/crl"
Success! Data written to: pki_int/ca/urls

Configure a role

The next step is to configure a role. A role is a logical name that maps to a policy used to generate those credentials. For example, let's create an "example-dot-com" role:

$ bao write pki_int/roles/example-dot-com \
    allowed_domains=example.com \
    allow_subdomains=true max_ttl=72h
Success! Data written to: pki_int/roles/example-dot-com

Issue certificates

By writing to the roles/example-dot-com path we are defining the example-dot-com role. To generate a new certificate, we simply write to the issue endpoint with that role name: OpenBao is now configured to create and manage certificates!

$ bao write pki_int/issue/example-dot-com \
    common_name=blah.example.com
Key                 Value
---                 -----
certificate         -----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
issuing_ca          -----BEGIN CERTIFICATE-----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==
-----END CERTIFICATE-----
ca_chain            [-----BEGIN CERTIFICATE-----
MIIDijCCAnKgAwIBAgIUB28DoGwgGFKL7fbOu9S4FalHLn0wDQYJKoZIhvcNAQEL
BQAwLzEtMCsGA1UEAxMkVmF1bHQgVGVzdGluZyBJbnRlcm1lZGlhdGUgQXV0aG9y
aXR5MB4XDTE2MDkyNzAwMDgyMVoXDTI2MDkxNjE2MDg1MVowMzExMC8GA1UEAxMo
VmF1bHQgVGVzdGluZyBJbnRlcm1lZGlhdGUgU3ViIEF1dGhvcml0eTCCASIwDQYJ
KoZIhvcNAQEBBQADggEPADCCAQoCggEBAOSCiSij4wy1wiMwvZt+rtU3IaO6ZTn9
LfIPuGsR5/QSJk37pCZQco1LgoE/rTl+/xu3bDovyHDmgObghC6rzVOX2Tpi7kD+
DOZpqxOsaS8ebYgxB/XJTSxyEJuSAcpSNLqqAiZivuQXdaD0N7H3Or0awwmKE9mD
I0g8CF4fPDmuuOG0ASn9fMqXVVt5tXtEqZ9yJYfNOXx3FOPjRVOZf+kvSc31wCKe
i/KmR0AQOmToKMzq988nLqFPTi9KZB8sEU20cGFeTQFol+m3FTcIru94EPD+nLUn
xtlLELVspYb/PP3VpvRj9b+DY8FGJ5nfSJl7Rkje+CD4VxJpSadin3kCAwEAAaOB
mTCBljAOBgNVHQ8BAf8EBAMCAQYwDwYDVR0TAQH/BAUwAwEB/zAdBgNVHQ4EFgQU
gM37P8oXmA972ztLfw+b1eIY5nowHwYDVR0jBBgwFoAUj4YAIxRwrBy0QMRKLnD0
kVidIuYwMwYDVR0RBCwwKoIoVmF1bHQgVGVzdGluZyBJbnRlcm1lZGlhdGUgU3Vi
IEF1dGhvcml0eTANBgkqhkiG9w0BAQsFAAOCAQEAA4buJuPNJvA1kiATLw1dVU2J
HPubk2Kp26Mg+GwLn7Vz45Ub133JCYfF3/zXLFZZ5Yub9gWTtjScrvNfQTAbNGdQ
BdnUlMmIRmfB7bfckhryR2R9byumeHATgNKZF7h8liNHI7X8tTzZGs6wPdXOLlzR
TlM3m1RNK8pbSPOkfPb06w9cBRlD8OAbNtJmuypXA6tYyiiMYBhP0QLAO3i4m1ns
aAjAgEjtkB1rQxW5DxoTArZ0asiIdmIcIGmsVxfDQIjFlRxAkafMs74v+5U5gbBX
wsOledU0fLl8KLq8W3OXqJwhGLK65fscrP0/omPAcFgzXf+L4VUADM4XhW6Xyg==
-----END CERTIFICATE-----]
private_key         -----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----
private_key_type    rsa
serial_number       3e:20:32:c6:af:a7:20:4e:b1:95:67:fb:86:bc:cb:90:f4:31:b6:f3

OpenBao has now generated a new set of credentials using the example-dot-com role configuration. Here we see the dynamically generated private key and certificate. The issuing CA certificate and CA trust chain are returned as well. The CA Chain returns all the intermediate authorities in the trust chain. The root authority is not included since that will usually be trusted by the underlying OS.

API

The PKI secrets engine has a full HTTP API. Please see the PKI secrets engine API for more details.