doc: describe certificate object properties

PR-URL: #24358
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>

Author: sam-github

doc/api/tls.md

@@ -638,44 +638,84 @@ added: v0.11.4
 
 * `detailed` {boolean} Include the full certificate chain if `true`, otherwise
   include just the peer's certificate.
-* Returns: {Object}
+* Returns: {Object} A certificate object.
 
-Returns an object representing the peer's certificate. The returned object has
-some properties corresponding to the fields of the certificate.
+Returns an object representing the peer's certificate. If the peer does not
+provide a certificate, an empty object will be returned. If the socket has been
+destroyed, `null` will be returned.
 
 If the full certificate chain was requested, each certificate will include an
 `issuerCertificate` property containing an object representing its issuer's
 certificate.
 
+#### Certificate Object
+
+A certificate object has properties corresponding to the fields of the
+certificate.
+
+* `raw` {Buffer} The DER encoded X.509 certificate data.
+* `subject` {Object} The certificate subject, described in terms of
+   Country (`C:`), StateOrProvince (`ST`), Locality (`L`), Organization (`O`),
+   OrganizationalUnit (`OU`), and CommonName (`CN`). The CommonName is typically
+   a DNS name with TLS certificates. Example:
+   `{C: 'UK', ST: 'BC', L: 'Metro', O: 'Node Fans', OU: 'Docs', CN: 'example.com'}`.
+* `issuer` {Object} The certificate issuer, described in the same terms as the
+   `subject`.
+* `valid_from` {string} The date-time the certificate is valid from.
+* `valid_to` {string} The date-time the certificate is valid to.
+* `serialNumber` {string} The certificate serial number, as a hex string.
+   Example: `'B9B0D332A1AA5635'`.
+* `fingerprint` {string} The SHA-1 digest of the DER encoded certificate. It is
+  returned as a `:` separated hexadecimal string. Example: `'2A:7A:C2:DD:...'`.
+* `fingerprint256` {string} The SHA-256 digest of the DER encoded certificate.
+   It is returned as a `:` separated hexadecimal string. Example:
+   `'2A:7A:C2:DD:...'`.
+* `ext_key_usage` {Array} (Optional) The extended key usage, a set of OIDs.
+* `subjectaltname` {Array} (Optional) An array of names for the subject, an
+   alternative to the `subject` names.
+* `infoAccess` {Array} (Optional) An array describing the AuthorityInfoAccess,
+   used with OCSP.
+* `issuerCert` {Object} (Optional) The issuer certificate object. For
+   self-signed certificates, this may be a circular reference.
+
+The certificate may contain information about the public key, depending on
+the key type.
+
+For RSA keys, the following properties may be defined:
+* `exponent` {string} The RSA exponent, as a string in hexadecimal number
+  notation.  Example: `'0x010001'`.
+* `modulus` {string} The RSA modulus, as a hexadecimal string. Example:
+   `'B56CE45CB7...'`.
+* `pubkey` {Buffer} The public key.
+
+
 ```text
 { subject:
-   { C: 'UK',
-     ST: 'Acknack Ltd',
-     L: 'Rhys Jones',
-     O: 'node.js',
-     OU: 'Test TLS Certificate',
-     CN: 'localhost' },
+   { OU: [ 'Domain Control Validated', 'PositiveSSL Wildcard' ],
+     CN: '*.nodejs.org' },
   issuer:
-   { C: 'UK',
-     ST: 'Acknack Ltd',
-     L: 'Rhys Jones',
-     O: 'node.js',
-     OU: 'Test TLS Certificate',
-     CN: 'localhost' },
-  issuerCertificate:
-   { ... another certificate, possibly with an .issuerCertificate ... },
-  raw: < RAW DER buffer >,
-  pubkey: < RAW DER buffer >,
-  valid_from: 'Nov 11 09:52:22 2009 GMT',
-  valid_to: 'Nov 6 09:52:22 2029 GMT',
-  fingerprint: '2A:7A:C2:DD:E5:F9:CC:53:72:35:99:7A:02:5A:71:38:52:EC:8A:DF',
-  fingerprint256: '2A:7A:C2:DD:E5:F9:CC:53:72:35:99:7A:02:5A:71:38:52:EC:8A:DF:00:11:22:33:44:55:66:77:88:99:AA:BB',
-  serialNumber: 'B9B0D332A1AA5635' }
+   { C: 'GB',
+     ST: 'Greater Manchester',
+     L: 'Salford',
+     O: 'COMODO CA Limited',
+     CN: 'COMODO RSA Domain Validation Secure Server CA' },
+  subjectaltname: 'DNS:*.nodejs.org, DNS:nodejs.org',
+  infoAccess:
+   { 'CA Issuers - URI':
+      [ 'http://crt.comodoca.com/COMODORSADomainValidationSecureServerCA.crt' ],
+     'OCSP - URI': [ 'http://ocsp.comodoca.com' ] },
+  modulus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
+  exponent: '0x10001',
+  pubkey: <Buffer ... >,
+  valid_from: 'Aug 14 00:00:00 2017 GMT',
+  valid_to: 'Nov 20 23:59:59 2019 GMT',
+  fingerprint: '01:02:59:D9:C3:D2:0D:08:F7:82:4E:44:A4:B4:53:C5:E2:3A:87:4D',
+  fingerprint256: '69:AE:1A:6A:D4:3D:C6:C1:1B:EA:C6:23:DE:BA:2A:14:62:62:93:5C:7A:EA:06:41:9B:0B:BC:87:CE:48:4E:02',
+  ext_key_usage: [ '1.3.6.1.5.5.7.3.1', '1.3.6.1.5.5.7.3.2' ],
+  serialNumber: '66593D57F20CBC573E433381B5FEC280',
+  raw: <Buffer ... > }
 ```
 
-If the peer does not provide a certificate, an empty object will be returned.
-If the socket has been destroyed, `null` will be returned.
-
 ### tlsSocket.getPeerFinished()
 <!-- YAML
 added: v9.9.0
@@ -830,8 +870,7 @@ added: v0.8.4
 
 * `hostname` {string} The host name or IP address to verify the certificate
   against.
-* `cert` {Object} An object representing the peer's certificate. The returned
-  object has some properties corresponding to the fields of the certificate.
+* `cert` {Object} A [certificate object][] representing the peer's certificate.
 * Returns: {Error|undefined}
 
 Verifies the certificate `cert` is issued to `hostname`.
@@ -847,36 +886,6 @@ the checks done with additional verification.
 This function is only called if the certificate passed all other checks, such as
 being issued by trusted CA (`options.ca`).
 
-The cert object contains the parsed certificate and will have a structure
-similar to:
-
-```text
-{ subject:
-   { OU: [ 'Domain Control Validated', 'PositiveSSL Wildcard' ],
-     CN: '*.nodejs.org' },
-  issuer:
-   { C: 'GB',
-     ST: 'Greater Manchester',
-     L: 'Salford',
-     O: 'COMODO CA Limited',
-     CN: 'COMODO RSA Domain Validation Secure Server CA' },
-  subjectaltname: 'DNS:*.nodejs.org, DNS:nodejs.org',
-  infoAccess:
-   { 'CA Issuers - URI':
-      [ 'http://crt.comodoca.com/COMODORSADomainValidationSecureServerCA.crt' ],
-     'OCSP - URI': [ 'http://ocsp.comodoca.com' ] },
-  modulus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
-  exponent: '0x10001',
-  pubkey: <Buffer ... >,
-  valid_from: 'Aug 14 00:00:00 2017 GMT',
-  valid_to: 'Nov 20 23:59:59 2019 GMT',
-  fingerprint: '01:02:59:D9:C3:D2:0D:08:F7:82:4E:44:A4:B4:53:C5:E2:3A:87:4D',
-  fingerprint256: '69:AE:1A:6A:D4:3D:C6:C1:1B:EA:C6:23:DE:BA:2A:14:62:62:93:5C:7A:EA:06:41:9B:0B:BC:87:CE:48:4E:02',
-  ext_key_usage: [ '1.3.6.1.5.5.7.3.1', '1.3.6.1.5.5.7.3.2' ],
-  serialNumber: '66593D57F20CBC573E433381B5FEC280',
-  raw: <Buffer ... > }
-```
-
 ## tls.connect(options[, callback])
 <!-- YAML
 added: v0.11.3
@@ -1396,5 +1405,6 @@ where `secureSocket` has the same API as `pair.cleartext`.
 [TLS Session Tickets]: https://www.ietf.org/rfc/rfc5077.txt
 [TLS recommendations]: https://wiki.mozilla.org/Security/Server_Side_TLS
 [asn1.js]: https://www.npmjs.com/package/asn1.js
+[certificate object]: #tls_certificate_object
 [modifying the default cipher suite]: #tls_modifying_the_default_tls_cipher_suite
 [specific attacks affecting larger AES key sizes]: https://www.schneier.com/blog/archives/2009/07/another_new_aes.html