use shlex.split

dulwich/client.py

@@ -43,6 +43,7 @@ from io import BytesIO, BufferedReader
 import logging
 import os
 import select
+import shlex
 import socket
 import subprocess
 import sys
@@ -1516,7 +1517,7 @@ class SubprocessSSHVendor(SSHVendor):
             )
 
         if ssh_command:
-            args = ssh_command.split() + ["-x"]
+            args = shlex.split(ssh_command) + ["-x"]
         else:
             args = ["ssh", "-x"]
 
@@ -1557,7 +1558,7 @@ class PLinkSSHVendor(SSHVendor):
     ):
 
         if ssh_command:
-            args = ssh_command.split() + ["-ssh"]
+            args = shlex.split(ssh_command) + ["-ssh"]
         elif sys.platform == "win32":
             args = ["plink.exe", "-ssh"]
         else: