gistfile1.txt

require 'openssl'
require 'net/http'

def cert_from_url(url)
  txt = Net::HTTP.get(URI(url))
  OpenSSL::X509::Certificate.new(txt)
end

LEAF_CERTIFICATE = OpenSSL::X509::Certificate.new %q[
-----BEGIN CERTIFICATE-----
MIIFKDCCBBCgAwIBAgISBP+uKglvwxGq302F+yCqxvnXMA0GCSqGSIb3DQEBCwUA
MDIxCzAJBgNVBAYTAlVTMRYwFAYDVQQKEw1MZXQncyBFbmNyeXB0MQswCQYDVQQD
EwJSMzAeFw0yMTA4MTEwOTAxMzdaFw0yMTExMDkwOTAxMzVaMBwxGjAYBgNVBAMT
EWdlb2lwLmVsYXN0aWMuZGV2MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKC
AQEAtazxd/2FWW1O5evHkDnPi4vcZJDFxs8V0tlI2ppf/OTymlBHMbzBE3BsUEP7
SkT+6kPnqQoy85S66zT4f2XyQfSWUZJeMPMcODl5P0SXEBlKv+ElRYvrsUpuc0ZH
ZTIM3+ueUY5M3Xmo9ao+I5evahr4Pf1laRWhHRLzFdKiMn7r1/qXf+PzKqZlzLng
cULtVpCTZlOk7CwrsAxwTYdFe1Z0b2ebKs793Ghag2V3D2YtCMuqLa1GP1sBsFRT
v1XPehXb5UOWffp3RJnUoG3n7K5cPI6G+fUAGRF3wxKuH+PYyW6/irb5+v4CVVSi
z+f29zDYeOc+baWGWFfymktslwIDAQABo4ICTDCCAkgwDgYDVR0PAQH/BAQDAgWg
MB0GA1UdJQQWMBQGCCsGAQUFBwMBBggrBgEFBQcDAjAMBgNVHRMBAf8EAjAAMB0G
A1UdDgQWBBQ23ntd4n192uVjxt9C0B18QYWMyzAfBgNVHSMEGDAWgBQULrMXt1hW
y65QCUDmH6+dixTCxjBVBggrBgEFBQcBAQRJMEcwIQYIKwYBBQUHMAGGFWh0dHA6
Ly9yMy5vLmxlbmNyLm9yZzAiBggrBgEFBQcwAoYWaHR0cDovL3IzLmkubGVuY3Iu
b3JnLzAcBgNVHREEFTATghFnZW9pcC5lbGFzdGljLmRldjBMBgNVHSAERTBDMAgG
BmeBDAECATA3BgsrBgEEAYLfEwEBATAoMCYGCCsGAQUFBwIBFhpodHRwOi8vY3Bz
LmxldHNlbmNyeXB0Lm9yZzCCAQQGCisGAQQB1nkCBAIEgfUEgfIA8AB1AH0+8viP
/4hVaCTCwMqeUol5K8UOeAl/LmqXaJl+IvDXAAABezSpB0oAAAQDAEYwRAIgC5B1
huzXAJCbtfWO5GGMVj930XNoNPGQj6o8yJfMQnMCIBdlncSV2rymFbZG7Q2PSAim
7/PkW/2qD3Vt8Ald8u3DAHcARJRlLrDuzq/EQAfYqP4owNrmgr7YyzG1P9MzlrW2
gagAAAF7NKkJHAAABAMASDBGAiEAnWU3nUNjdHdrE62v0y45WDLj6eyfXkIxAh9Z
GAA2wJACIQDtKZNFze3mAj7pE6m3AZMfnq4N0VvO2Ahr0HbpN/xWzDANBgkqhkiG
9w0BAQsFAAOCAQEABWFFyolbYnyqDA8ckU0Lm7btCM78CeljjKxVCGTqhlntJhhH
NBJcRArzCBkres7Z4yySiJ1vSUXNVvGITVCi2d/zJ5SxBDoT5v8IjEb98KH//9u3
Jb1CfuEADhnEUXjyf4GeIiTHtdKX36jGwTRO3YIa52G6HONbOnQBgcwn8FpYJdIj
3C58o5AxWRcVVQbaCFxjGcCLSUSQsJxzilsYE+xVqc+d5GftG3Nmy6l3Ht84693n
UwMrb/rlsQC163gtdVEN/GFCeLU+UfFGuSeCmUM3SmAIVfD/yjLvisVpf70pV0Jg
p1Px196NI71smu8LxrhX78ErTrR4GpDkx4W+uw==
-----END CERTIFICATE-----
]

cert_store = OpenSSL::X509::Store.new
cert_store.set_default_paths

OpenSSL::SSL::VERIFY_PEER = OpenSSL::SSL::VERIFY_NONE

chain = [
  # Intermediate cert from expired CA
  cert_from_url("https://letsencrypt.org/certs/lets-encrypt-r3-cross-signed.pem"),
  # Valid Intermediate cert
  cert_from_url("https://letsencrypt.org/certs/lets-encrypt-r3.pem"),
]
OpenSSL::SSL::VERIFY_PEER = OpenSSL::SSL::VERIFY_PEER
cert_store.verify(LEAF_CERTIFICATE, chain)

pp cert_store.chain
puts cert_store.error
puts cert_store.error_string