SSH disabled algorithms (#2648)

* Add support for SSH disabled_algorithms parameter introduced in Paramiko 2.6.0

* Fixing test issue; adding Zyxel platform to docs as forgot to add it earlier

* Simplifying type hints

Co-authored-by: Baptiste Jonglez <baptiste.jonglez@inria.fr>

PLATFORMS.md

@@ -91,6 +91,7 @@
 - Ubiquiti Unifi Switch
 - Versa Networks FlexVNF
 - Watchguard Firebox
+- Zyxel NOS
 - 6WIND TurboRouter
 
 ###### Supported SSH device_type values
@@ -207,6 +208,7 @@
 - watchguard_fireware
 - yamaha
 - zte_zxros
+- zyxel_os
  
 ###### Supported Telnet device_type values
  

netmiko/base_connection.py

@@ -145,6 +145,7 @@ class BaseConnection:
         key_file: Optional[str] = None,
         pkey: Optional[paramiko.PKey] = None,
         passphrase: Optional[str] = None,
+        disabled_algorithms: Optional[Dict[str, Any]] = None,
         allow_agent: bool = False,
         ssh_strict: bool = False,
         system_host_keys: bool = False,
@@ -214,6 +215,9 @@ class BaseConnection:
         :param passphrase: Passphrase to use for encrypted key; password will be used for key
                 decryption if not specified.
 
+        :param disabled_algorithms: Dictionary of SSH algorithms to disable. Refer to the Paramiko
+                documentation for a description of the expected format.
+
         :param allow_agent: Enable use of SSH key-agent.
 
         :param ssh_strict: Automatically reject unknown SSH host keys (default: False, which
@@ -419,6 +423,7 @@ class BaseConnection:
             self.system_host_keys = system_host_keys
             self.alt_host_keys = alt_host_keys
             self.alt_key_file = alt_key_file
+            self.disabled_algorithms = disabled_algorithms or {}
 
             # For SSH proxy support
             self.ssh_config_file = ssh_config_file
@@ -954,6 +959,7 @@ You can look at the Netmiko session_log or debug log for more information.
             "key_filename": self.key_file,
             "pkey": self.pkey,
             "passphrase": self.passphrase,
+            "disabled_algorithms": self.disabled_algorithms,
             "timeout": self.conn_timeout,
             "auth_timeout": self.auth_timeout,
             "banner_timeout": self.banner_timeout,

tests/unit/test_base_connection.py

@@ -56,6 +56,7 @@ def test_use_ssh_file():
         timeout=60,
         pkey=None,
         passphrase=None,
+        disabled_algorithms=None,
         auth_timeout=None,
         banner_timeout=10,
         conn_timeout=5,
@@ -76,6 +77,7 @@ def test_use_ssh_file():
         "timeout": 5,
         "pkey": None,
         "passphrase": None,
+        "disabled_algorithms": None,
         "auth_timeout": None,
         "banner_timeout": 10,
     }
@@ -101,6 +103,7 @@ def test_use_ssh_file_proxyjump():
         timeout=60,
         pkey=None,
         passphrase=None,
+        disabled_algorithms=None,
         auth_timeout=None,
         conn_timeout=5,
         banner_timeout=10,
@@ -121,6 +124,7 @@ def test_use_ssh_file_proxyjump():
         "timeout": 5,
         "pkey": None,
         "passphrase": None,
+        "disabled_algorithms": None,
         "auth_timeout": None,
         "banner_timeout": 10,
     }
@@ -145,6 +149,7 @@ def test_connect_params_dict():
         timeout=60,
         pkey=None,
         passphrase=None,
+        disabled_algorithms=None,
         auth_timeout=None,
         banner_timeout=10,
         conn_timeout=3,
@@ -163,6 +168,7 @@ def test_connect_params_dict():
         "timeout": 3,
         "pkey": None,
         "passphrase": None,
+        "disabled_algorithms": None,
         "auth_timeout": None,
         "banner_timeout": 10,
         "sock": None,