openssl_publickey: fix handling of OpenSSH private keys with passphrase (#54192)

* Cleanup.
* Make sure that OpenSSH passphrases are handled correctly.
* Add changelog.

(cherry picked from commit 1a94cf140c)

changelogs/fragments/54192-openssl_publickey-openssh-passphrase.yml

@@ -0,0 +1,2 @@
+bugfixes:
+- "openssl_publickey - fixed crash on Python 3 when OpenSSH private keys were used with passphrases."

lib/ansible/modules/crypto/openssl_publickey.py

@@ -123,7 +123,6 @@ fingerprint:
       sha512: "fd:ed:5e:39:48:5f:9f:fe:7f:25:06:3f:79:08:cd:ee:a5:e7:b3:3d:13:82:87:1f:84:e1:f5:c7:28:77:53:94:86:56:38:69:f0:d9:35:22:01:1e:a6:60:...:0f:9b"
 '''
 
-import hashlib
 import os
 
 try:
@@ -136,7 +135,7 @@ else:
     pyopenssl_found = True
 
 from ansible.module_utils import crypto as crypto_utils
-from ansible.module_utils._text import to_native
+from ansible.module_utils._text import to_native, to_bytes
 from ansible.module_utils.basic import AnsibleModule
 
 
@@ -170,10 +169,13 @@ class PublicKey(crypto_utils.OpenSSLObject):
         if not self.check(module, perms_required=False) or self.force:
             try:
                 if self.format == 'OpenSSH':
-                    privatekey_content = open(self.privatekey_path, 'rb').read()
-                    key = crypto_serialization.load_pem_private_key(privatekey_content,
-                                                                    password=self.privatekey_passphrase,
-                                                                    backend=default_backend())
+                    with open(self.privatekey_path, 'rb') as private_key_fh:
+                        privatekey_content = private_key_fh.read()
+                    key = crypto_serialization.load_pem_private_key(
+                        privatekey_content,
+                        password=None if self.privatekey_passphrase is None else to_bytes(self.privatekey_passphrase),
+                        backend=default_backend()
+                    )
                     publickey_content = key.public_key().public_bytes(
                         crypto_serialization.Encoding.OpenSSH,
                         crypto_serialization.PublicFormat.OpenSSH