pki: eapol: T4245: Add full CA and client cert chains to wpa_supplicant PEM files

This commit updates the eapol code so that it writes the full
certificate chains for both the specified CA and the client certificate
to `<iface>_ca.pem` and `<iface>_cert.pem`, respectively.

The full CA chain is necessary for validating the incoming server
certificate when it is signed by an intermediate CA and the
intermediate CA cert is not included in the EAP-TLS ServerHello. In this
scenario, wpa_supplicant needs to have both the intermediate CA and the
root CA in its `ca_file`.

Similarly, the full client certificate chain is needed when the ISP
expects/requires that the client (wpa_supplicant) sends the client cert
+ the intermediate CA (or even + the root CA) as part of the EAP-TLS
ClientHello.

Signed-off-by: Andrew Gunnerson <chillermillerlong@hotmail.com>

3 files changed, 125 insertions, 27 deletions

diff --git a/python/vyos/pki.py b/python/vyos/pki.py
index 68ad73bf2..0b916eaae 100644
--- a/python/vyos/pki.py
+++ b/python/vyos/pki.py
@@ -331,3 +331,29 @@ def verify_certificate(cert, ca_cert):
         return True
     except InvalidSignature:
         return False
+
+# Certificate chain
+
+def find_parent(cert, ca_certs):
+    for ca_cert in ca_certs:
+        if verify_certificate(cert, ca_cert):
+            return ca_cert
+    return None
+
+def find_chain(cert, ca_certs):
+    remaining = ca_certs.copy()
+    chain = [cert]
+
+    while remaining:
+        parent = find_parent(chain[-1], remaining)
+        if parent is None:
+            # No parent in the list of remaining certificates or there's a circular dependency
+            break
+        elif parent == chain[-1]:
+            # Self-signed: must be root CA (end of chain)
+            break
+        else:
+            remaining.remove(parent)
+            chain.append(parent)
+
+    return chain
diff --git a/smoketest/scripts/cli/test_interfaces_ethernet.py b/smoketest/scripts/cli/test_interfaces_ethernet.py
index 6d80e4c96..ae3d5ed96 100755
--- a/smoketest/scripts/cli/test_interfaces_ethernet.py
+++ b/smoketest/scripts/cli/test_interfaces_ethernet.py
@@ -21,29 +21,73 @@ import unittest
 from base_interfaces_test import BasicInterfaceTest
 from vyos.configsession import ConfigSessionError
 from vyos.ifconfig import Section
+from vyos.pki import CERT_BEGIN
 from vyos.util import cmd
 from vyos.util import process_named_running
 from vyos.util import read_file
 
-cert_data = """
-MIICFDCCAbugAwIBAgIUfMbIsB/ozMXijYgUYG80T1ry+mcwCgYIKoZIzj0EAwIw
-WTELMAkGA1UEBhMCR0IxEzARBgNVBAgMClNvbWUtU3RhdGUxEjAQBgNVBAcMCVNv
-bWUtQ2l0eTENMAsGA1UECgwEVnlPUzESMBAGA1UEAwwJVnlPUyBUZXN0MB4XDTIx
-MDcyMDEyNDUxMloXDTI2MDcxOTEyNDUxMlowWTELMAkGA1UEBhMCR0IxEzARBgNV
-BAgMClNvbWUtU3RhdGUxEjAQBgNVBAcMCVNvbWUtQ2l0eTENMAsGA1UECgwEVnlP
-UzESMBAGA1UEAwwJVnlPUyBUZXN0MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE
-01HrLcNttqq4/PtoMua8rMWEkOdBu7vP94xzDO7A8C92ls1v86eePy4QllKCzIw3
-QxBIoCuH2peGRfWgPRdFsKNhMF8wDwYDVR0TAQH/BAUwAwEB/zAOBgNVHQ8BAf8E
-BAMCAYYwHQYDVR0lBBYwFAYIKwYBBQUHAwIGCCsGAQUFBwMBMB0GA1UdDgQWBBSu
-+JnU5ZC4mkuEpqg2+Mk4K79oeDAKBggqhkjOPQQDAgNHADBEAiBEFdzQ/Bc3Lftz
-ngrY605UhA6UprHhAogKgROv7iR4QgIgEFUxTtW3xXJcnUPWhhUFhyZoqfn8dE93
-+dm/LDnp7C0=
+server_ca_root_cert_data = """
+MIIBcTCCARagAwIBAgIUDcAf1oIQV+6WRaW7NPcSnECQ/lUwCgYIKoZIzj0EAwIw
+HjEcMBoGA1UEAwwTVnlPUyBzZXJ2ZXIgcm9vdCBDQTAeFw0yMjAyMTcxOTQxMjBa
+Fw0zMjAyMTUxOTQxMjBaMB4xHDAaBgNVBAMME1Z5T1Mgc2VydmVyIHJvb3QgQ0Ew
+WTATBgcqhkjOPQIBBggqhkjOPQMBBwNCAAQ0y24GzKQf4aM2Ir12tI9yITOIzAUj
+ZXyJeCmYI6uAnyAMqc4Q4NKyfq3nBi4XP87cs1jlC1P2BZ8MsjL5MdGWozIwMDAP
+BgNVHRMBAf8EBTADAQH/MB0GA1UdDgQWBBRwC/YaieMEnjhYa7K3Flw/o0SFuzAK
+BggqhkjOPQQDAgNJADBGAiEAh3qEj8vScsjAdBy5shXzXDVVOKWCPTdGrPKnu8UW
+a2cCIQDlDgkzWmn5ujc5ATKz1fj+Se/aeqwh4QyoWCVTFLIxhQ==
 """
 
-key_data = """
-MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQgPLpD0Ohhoq0g4nhx
-2KMIuze7ucKUt/lBEB2wc03IxXyhRANCAATTUestw222qrj8+2gy5rysxYSQ50G7
-u8/3jHMM7sDwL3aWzW/zp54/LhCWUoLMjDdDEEigK4fal4ZF9aA9F0Ww
+server_ca_intermediate_cert_data = """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+"""
+
+client_ca_root_cert_data = """
+MIIBcDCCARagAwIBAgIUZmoW2xVdwkZSvglnkCq0AHKa6zIwCgYIKoZIzj0EAwIw
+HjEcMBoGA1UEAwwTVnlPUyBjbGllbnQgcm9vdCBDQTAeFw0yMjAyMTcxOTQxMjFa
+Fw0zMjAyMTUxOTQxMjFaMB4xHDAaBgNVBAMME1Z5T1MgY2xpZW50IHJvb3QgQ0Ew
+WTATBgcqhkjOPQIBBggqhkjOPQMBBwNCAATUpKXzQk2NOVKDN4VULk2yw4mOKPvn
+mg947+VY7lbpfOfAUD0QRg95qZWCw899eKnXp/U4TkAVrmEKhUb6OJTFozIwMDAP
+BgNVHRMBAf8EBTADAQH/MB0GA1UdDgQWBBTXu6xGWUl25X3sBtrhm3BJSICIATAK
+BggqhkjOPQQDAgNIADBFAiEAnTzEwuTI9bz2Oae3LZbjP6f/f50KFJtjLZFDbQz7
+DpYCIDNRHV8zBUibC+zg5PqMpQBKd/oPfNU76nEv6xkp/ijO
+"""
+
+client_ca_intermediate_cert_data = """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+"""
+
+client_cert_data = """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+"""
+
+client_key_data = """
+MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQgxaxAQsJwjoOCByQE
++qSYKtKtJzbdbOnTsKNSrfgkFH6hRANCAARuyynqfc/qJj5eKJ03oOH8X4Z8spDe
+APO9WYckMM0ldPj+9kU607szFzPwjaPWzPdgyIWz3hcN8yAhCIhytmJa
 """
 
 def get_wpa_supplicant_value(interface, key):
@@ -51,6 +95,10 @@ def get_wpa_supplicant_value(interface, key):
     tmp = re.findall(r'\n?{}=(.*)'.format(key), tmp)
     return tmp[0]
 
+def get_certificate_count(interface, cert_type):
+    tmp = read_file(f'/run/wpa_supplicant/{interface}_{cert_type}.pem')
+    return tmp.count(CERT_BEGIN)
+
 class EthernetInterfaceTest(BasicInterfaceTest.TestCase):
     @classmethod
     def setUpClass(cls):
@@ -165,16 +213,23 @@ class EthernetInterfaceTest(BasicInterfaceTest.TestCase):
             self.cli_commit()
 
     def test_eapol_support(self):
-        ca_name = 'eapol'
-        cert_name = 'eapol'
+        ca_certs = {
+            'eapol-server-ca-root': server_ca_root_cert_data,
+            'eapol-server-ca-intermediate': server_ca_intermediate_cert_data,
+            'eapol-client-ca-root': client_ca_root_cert_data,
+            'eapol-client-ca-intermediate': client_ca_intermediate_cert_data,
+        }
+        cert_name = 'eapol-client'
 
-        self.cli_set(['pki', 'ca', ca_name, 'certificate', cert_data.replace('\n','')])
-        self.cli_set(['pki', 'certificate', cert_name, 'certificate', cert_data.replace('\n','')])
-        self.cli_set(['pki', 'certificate', cert_name, 'private', 'key', key_data.replace('\n','')])
+        for name, data in ca_certs.items():
+            self.cli_set(['pki', 'ca', name, 'certificate', data.replace('\n','')])
+
+        self.cli_set(['pki', 'certificate', cert_name, 'certificate', client_cert_data.replace('\n','')])
+        self.cli_set(['pki', 'certificate', cert_name, 'private', 'key', client_key_data.replace('\n','')])
 
         for interface in self._interfaces:
             # Enable EAPoL
-            self.cli_set(self._base_path + [interface, 'eapol', 'ca-certificate', ca_name])
+            self.cli_set(self._base_path + [interface, 'eapol', 'ca-certificate', 'eapol-server-ca-intermediate'])
             self.cli_set(self._base_path + [interface, 'eapol', 'certificate', cert_name])
 
         self.cli_commit()
@@ -206,7 +261,12 @@ class EthernetInterfaceTest(BasicInterfaceTest.TestCase):
             tmp = get_wpa_supplicant_value(interface, 'identity')
             self.assertEqual(f'"{mac}"', tmp)
 
-        self.cli_delete(['pki', 'ca', ca_name])
+        # Check certificate files have the full chain
+        self.assertEqual(get_certificate_count(interface, 'ca'), 2)
+        self.assertEqual(get_certificate_count(interface, 'cert'), 3)
+
+        for name in ca_certs:
+            self.cli_delete(['pki', 'ca', name])
         self.cli_delete(['pki', 'certificate', cert_name])
 
 if __name__ == '__main__':
diff --git a/src/conf_mode/interfaces-ethernet.py b/src/conf_mode/interfaces-ethernet.py
index ab8d58f81..2a8a126f2 100755
--- a/src/conf_mode/interfaces-ethernet.py
+++ b/src/conf_mode/interfaces-ethernet.py
@@ -32,7 +32,9 @@ from vyos.configverify import verify_vlan_config
 from vyos.configverify import verify_vrf
 from vyos.ethtool import Ethtool
 from vyos.ifconfig import EthernetIf
-from vyos.pki import wrap_certificate
+from vyos.pki import find_chain
+from vyos.pki import encode_certificate
+from vyos.pki import load_certificate
 from vyos.pki import wrap_private_key
 from vyos.template import render
 from vyos.util import call
@@ -159,7 +161,14 @@ def generate(ethernet):
         cert_name = ethernet['eapol']['certificate']
         pki_cert = ethernet['pki']['certificate'][cert_name]
 
-        write_file(cert_file_path, wrap_certificate(pki_cert['certificate']))
+        loaded_pki_cert = load_certificate(pki_cert['certificate'])
+        loaded_ca_certs = {load_certificate(c['certificate'])
+            for c in ethernet['pki']['ca'].values()}
+
+        cert_full_chain = find_chain(loaded_pki_cert, loaded_ca_certs)
+
+        write_file(cert_file_path,
+                   '\n'.join(encode_certificate(c) for c in cert_full_chain))
         write_file(cert_key_path, wrap_private_key(pki_cert['private']['key']))
 
         if 'ca_certificate' in ethernet['eapol']:
@@ -167,8 +176,11 @@ def generate(ethernet):
             ca_cert_name = ethernet['eapol']['ca_certificate']
             pki_ca_cert = ethernet['pki']['ca'][ca_cert_name]
 
+            loaded_ca_cert = load_certificate(pki_ca_cert['certificate'])
+            ca_full_chain = find_chain(loaded_ca_cert, loaded_ca_certs)
+
             write_file(ca_cert_file_path,
-                       wrap_certificate(pki_ca_cert['certificate']))
+                       '\n'.join(encode_certificate(c) for c in ca_full_chain))
     else:
         # delete configuration on interface removal
         if os.path.isfile(wpa_suppl_conf.format(**ethernet)):