From 6c4f54130d892f5034ac40d139ff27b8bb4d1927 Mon Sep 17 00:00:00 2001
From: zhangpan <zhangpan103@h-partners.com>
Date: Fri, 12 Apr 2024 12:47:45 +0800
Subject: [PATCH] Add Insecure Algorithm Logs

---
 paramiko/auth_handler.py |  5 ++++
 paramiko/transport.py    | 65 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 70 insertions(+)

diff --git a/paramiko/auth_handler.py b/paramiko/auth_handler.py
index db89670..0454358 100644
--- a/paramiko/auth_handler.py
+++ b/paramiko/auth_handler.py
@@ -384,6 +384,11 @@ class AuthHandler(object):
                 m.add_boolean(True)
                 key_type, bits = self._get_key_type_and_bits(self.private_key)
                 algorithm = self._finalize_pubkey_algorithm(key_type)
+                if not list (
+                        filter(
+                            algorithm.__contains__,
+                            self.transport._whitelist_pubkeys)):
+                    self._log(WARNING, "Insecure PubKey algorithm may be used: {}".format(algorithm))
                 m.add_string(algorithm)
                 m.add_string(bits)
                 blob = self._get_session_blob(
diff --git a/paramiko/transport.py b/paramiko/transport.py
index 5265e09..e8ff0e0 100644
--- a/paramiko/transport.py
+++ b/paramiko/transport.py
@@ -213,6 +213,43 @@ class Transport(threading.Thread, ClosingContextManager):
     )
     _preferred_compression = ("none",)
 
+    _whitelist_ciphers = (
+        "aes128-ctr",
+        "aes192-ctr",
+        "aes256-ctr",
+        "chacha20-poly1305@openssh.com",
+        "aes128-gcm@openssh.com",
+        "aes256-gcm@openssh.com",
+    )
+
+    _whitelist_macs = (
+        "hmac-sha2-512",
+        "hmac-sha2-512-etm@openssh.com",
+        "hmac-sha2-256",
+        "hmac-sha2-256-etm@openssh.com",
+    )
+
+    _whitelist_keys = (
+        "ssh-ed25519",
+        "ecdsa-sha2-nistp256",
+        "ssh-ed25519-cert-v01@openssh.com",
+        "rsa-sha2-256",
+        "rsa-sha2-512",
+    )
+
+    _whitelist_pubkeys = (
+        "ssh-ed25519",
+        "ssh-ed25519-cert-v01@openssh.com",
+        "rsa-sha2-256",
+        "rsa-sha2-512",
+    )
+
+    _whitelist_kex = (
+        "curve25519-sha256",
+        "curve25519-sha256@libssh.org",
+        "diffie-hellman-group-exchange-sha256",
+    )
+
     _cipher_info = {
         "aes128-ctr": {
             "class": algorithms.AES,
@@ -2507,6 +2544,13 @@ class Transport(threading.Thread, ClosingContextManager):
                 "Incompatible ssh peer (no acceptable kex algorithm)"
             )  # noqa
         self.kex_engine = self._kex_info[agreed_kex[0]](self)
+
+        if not list (
+                filter(
+                    agreed_kex[0].__contains__,
+                    self._whitelist_kex)):
+            self._log(WARNING, "Insecure Kex algorithm may be used: {}".format(agreed_kex[0]))
+
         self._log(DEBUG, "Kex: {}".format(agreed_kex[0]))
 
         if self.server_mode:
@@ -2534,6 +2578,13 @@ class Transport(threading.Thread, ClosingContextManager):
             raise IncompatiblePeer(
                 "Incompatible ssh peer (can't match requested host key type)"
             )  # noqa
+
+        if not list (
+                filter(
+                    self.host_key_type.__contains__,
+                    self._whitelist_keys)):
+            self._log(WARNING, "Insecure HostKey algorithm may be used: {}".format(self.host_key_type))
+
         self._log_agreement("HostKey", agreed_keys[0], agreed_keys[0])
 
         if self.server_mode:
@@ -2568,6 +2619,13 @@ class Transport(threading.Thread, ClosingContextManager):
             )  # noqa
         self.local_cipher = agreed_local_ciphers[0]
         self.remote_cipher = agreed_remote_ciphers[0]
+
+        if not list (
+                filter(
+                    self.local_cipher.__contains__,
+                    self._whitelist_ciphers)):
+            self._log(WARNING, "Insecure Cipher algorithm may be used: {}".format(self.local_cipher))
+
         self._log_agreement(
             "Cipher", local=self.local_cipher, remote=self.remote_cipher
         )
@@ -2592,6 +2650,13 @@ class Transport(threading.Thread, ClosingContextManager):
             )
         self.local_mac = agreed_local_macs[0]
         self.remote_mac = agreed_remote_macs[0]
+
+        if not list (
+                filter(
+                    self.local_mac.__contains__,
+                    self._whitelist_macs)):
+            self._log(WARNING, "Insecure Mac algorithm may be used: {}".format(self.local_mac))
+
         self._log_agreement(
             "MAC", local=self.local_mac, remote=self.remote_mac
         )
-- 
2.33.0