fix(ssh): ssh.which returning None for POSIX paths when running on Windows (#2732)

* fix(ssh): use POSIX separator for path detection in ssh.which

On Windows, `os.path.sep` is '\\', which fails to detect POSIX paths.
Hardcoding '/' ensures consistent path detection since the `ssh`
module targets POSIX-compliant systems.

* Update CHANGELOG.md

* feat(context): add path_sep and pathlist_sep to context, make the path seperator dependent on the context.os

* fix(ssh): declare path separator as private member in ssh

* fix(ssh): remote path handling with pathlib

* fix(ssh): replace os.path.basename functions with pathlib for path handling

* fix(ssh): ensure remote paths are decoded to str

Author: enihsyou

CHANGELOG.md

@@ -136,6 +136,7 @@ The table below shows which release corresponds to each branch, and what date th
 - [#2702][2702] ssh: Don't cache username in ssh checksec output
 - [#2722][2722] safeeval: allow LIST_APPEND and SET_ADD opcodes (Python 3.14)
 - [#2730][2730] Fix atexception handlers in term mode
+- [#2732][2732] ssh: fix `ssh.which` returns None for POSIX paths when running on Windows
 - [#2733][2733] loongarch64: fix incorrect mov assembly template
 - [#2746][2746] elf: point people at libc_start_main_return when they look up __libc_start_main_ret
 
@@ -197,6 +198,7 @@ The table below shows which release corresponds to each branch, and what date th
 [2722]: https://github.com/Gallopsled/pwntools/pull/2722
 [2725]: https://github.com/Gallopsled/pwntools/pull/2725
 [2730]: https://github.com/Gallopsled/pwntools/pull/2730
+[2732]: https://github.com/Gallopsled/pwntools/pull/2732
 [2733]: https://github.com/Gallopsled/pwntools/pull/2733
 [2739]: https://github.com/Gallopsled/pwntools/pull/2739
 [2740]: https://github.com/Gallopsled/pwntools/pull/2740

pwnlib/tubes/ssh.py

@@ -1,5 +1,6 @@
 import logging
 import os
+import pathlib
 import re
 import shutil
 import string
@@ -592,6 +593,8 @@ class ssh(Timeout, Logger):
     pid = None
 
     _cwd = '.'
+    _sep = '/'
+    _pathlib = pathlib.PurePosixPath
     _tried_sftp = False
 
     def __init__(self, user=None, host=None, port=22, password=None, key=None,
@@ -696,6 +699,10 @@ def __init__(self, user=None, host=None, port=22, password=None, key=None,
 
         misc.mkdir_p(self._cachedir)
 
+        if context.os == 'windows':
+            self._sep = '\\'
+            self._pathlib = pathlib.PureWindowsPath    
+
         import paramiko
 
         # Make a basic attempt to parse the ssh_config file
@@ -1122,14 +1129,15 @@ def which(self, program):
         system which adds the current working directory to the end of ``$PATH``.
         """
         # If name is a path, do not attempt to resolve it.
-        if os.path.sep in program:
+        if self._sep in program:
             return program
 
         program = packing._encode(program)
+        pathsep = self._sep.encode()
 
         result = self.system(b'export PATH=$PATH:$PWD; command -v ' + program).recvall().strip()
 
-        if (b'/' + program) not in result:
+        if (pathsep + program) not in result:
             return None
 
         return packing._decode(result)
@@ -1471,8 +1479,7 @@ def _download_to_cache(self, remote, p, fingerprint=True):
 
         fingerprint = fingerprint and self._get_fingerprint(remote) or None
         if fingerprint is None:
-            local = os.path.normpath(remote)
-            local = os.path.basename(local)
+            local = self._pathlib(remote).name
             local += time.strftime('-%Y-%m-%d-%H%M%S')
             local = os.path.join(self._cachedir, local)
 
@@ -1541,7 +1548,8 @@ def download_file(self, remote, local = None):
 
 
         if not local:
-            local = os.path.basename(os.path.normpath(remote))
+            remote_str = remote.decode() if not hasattr(remote, 'encode') else remote
+            local = self._pathlib(remote_str).name
 
         with self.progress('Downloading %r to %r' % (remote, local)) as p:
             local_tmp = self._download_to_cache(remote, p)
@@ -1617,9 +1625,12 @@ def upload_data(self, data, remote):
             Hello, world
         """
         data = packing._need_bytes(data)
+        if not hasattr(remote, 'encode'):
+            remote = remote.decode('utf-8')
         # If a relative path was provided, prepend the cwd
-        if os.path.normpath(remote) == os.path.basename(remote):
-            remote = os.path.join(self.cwd, remote)
+        remote_path = self._pathlib(remote)
+        if str(remote_path) == remote_path.name:
+            remote = str(self._pathlib(self.cwd) / remote)
 
         if self.sftp:
             flo = BytesIO(data)
@@ -1650,9 +1661,7 @@ def upload_file(self, filename, remote = None):
 
 
         if remote is None:
-            remote = os.path.normpath(filename)
-            remote = os.path.basename(remote)
-            remote = os.path.join(self.cwd, remote)
+            remote = str(self._pathlib(self.cwd) / self._pathlib(filename).name)
 
         with open(filename, 'rb') as fd:
             data = fd.read()
@@ -1909,7 +1918,7 @@ def set_working_directory(self, wd = None, symlink = False):
         status = 0
 
         if symlink and not isinstance(symlink, (bytes, str)):
-            symlink = os.path.join(self.pwd(), b'*')
+            symlink = str(self._pathlib(self.pwd().decode()) / '*')
         if not hasattr(symlink, 'encode') and hasattr(symlink, 'decode'):
             symlink = symlink.decode('utf-8')