[tor-commits] [stem/master] Trailing whitespace broke 'ss' connection resolution

[atagar at torproject.org]

commit 8a00dcb0cd1bf00e6fc5ea315de555882a175683
Author: Damian Johnson <atagar at torproject.org>
Date:   Fri Sep 11 15:56:37 2020 -0700

    Trailing whitespace broke 'ss' connection resolution
    
    Some platforms append trailing whitespace to the output of the 'ss' command.
    Caught thanks to toralf...
    
      https://github.com/torproject/stem/issues/46
    
    Determined the problem by running the following against toralf's output...
    
      from stem.util.connection import Resolver, get_connections
      from unittest.mock import patch
    
      with open('ss-nptu.log') as ss_file:
        ss_output = ss_file.read()
    
      with patch('stem.util.system.call') as call_mock:
        call_mock.return_value = ss_output.split('\n')
    
        print('parsed %i connections' % len(get_connections(Resolver.SS, process_pid = 2238, process_name = 'tor')))
    
    Before:
    
      % python3.7 demo.py
      Traceback (most recent call last):
        File "demo.py", line 12, in <module>
          print('parsed %i connections' % len(get_connections(Resolver.SS, process_pid = 2238, process_name = 'tor')))
        File "/home/atagar/Desktop/stem/stem/util/connection.py", line 333, in get_connections
          raise OSError('No results found using: %s' % resolver_command)
      OSError: No results found using: ss -nptu
    
    After:
    
      % python3.7 demo.py
      parsed 8114 connections
---
 docs/change_log.rst          |  4 ++++
 stem/util/connection.py      |  2 +-
 test/settings.cfg            |  1 +
 test/unit/util/connection.py | 19 +++++++++++++++++++
 4 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/docs/change_log.rst b/docs/change_log.rst
index 5a9a8928..cc830d6c 100644
--- a/docs/change_log.rst
+++ b/docs/change_log.rst
@@ -67,6 +67,10 @@ The following are only available within Stem's `git repository
 
   * *transport* lines within extrainfo descriptors failed to validate
 
+ * **Utilities**
+
+  * *ss* connection resolver failed on platforms that append whitespace (:ticket:`46`)
+
  * **Installation**
 
   * Migrated from distutil to setuptools
diff --git a/stem/util/connection.py b/stem/util/connection.py
index a83922f7..2198d526 100644
--- a/stem/util/connection.py
+++ b/stem/util/connection.py
@@ -126,7 +126,7 @@ RESOLVER_FILTER = {
   Resolver.NETSTAT_WINDOWS: '^\\s*{protocol}\\s+{local}\\s+{remote}\\s+ESTABLISHED\\s+{pid}\\s*$',
 
   # tcp    ESTAB      0      0           192.168.0.20:44415       38.229.79.2:443    users:(("tor",15843,9))
-  Resolver.SS: '^{protocol}\\s+ESTAB\\s+.*\\s+{local}\\s+{remote}\\s+users:\\(\\("{name}",(?:pid=)?{pid},(?:fd=)?[0-9]+\\)\\)$',
+  Resolver.SS: '^{protocol}\\s+ESTAB\\s+.*\\s+{local}\\s+{remote}\\s+users:\\(\\("{name}",(?:pid=)?{pid},(?:fd=)?[0-9]+\\)\\)\\s*$',
 
   # tor  3873  atagar  45u  IPv4  40994  0t0  TCP 10.243.55.20:45724->194.154.227.109:9001 (ESTABLISHED)
   Resolver.LSOF: '^{name}\\s+{pid}\\s+.*\\s+{protocol}\\s+{local}->{remote} \\(ESTABLISHED\\)$',
diff --git a/test/settings.cfg b/test/settings.cfg
index e49835ea..b1d26d92 100644
--- a/test/settings.cfg
+++ b/test/settings.cfg
@@ -188,6 +188,7 @@ pycodestyle.ignore stem/descriptor/__init__.py => E402: import stem.descriptor.s
 pycodestyle.ignore stem/descriptor/__init__.py => E402: import stem.descriptor.tordnsel
 pycodestyle.ignore test/unit/util/connection.py => W291: _tor     tor        15843   10 pipe 0x0 state:
 pycodestyle.ignore test/unit/util/connection.py => W291: _tor     tor        15843   11 pipe 0x0 state:
+pycodestyle.ignore test/unit/util/connection.py => W291: tcp    ESTAB
 
 # False positives from pyflakes. These are mappings between the path and the
 # issue.
diff --git a/test/unit/util/connection.py b/test/unit/util/connection.py
index 575667b4..24020c55 100644
--- a/test/unit/util/connection.py
+++ b/test/unit/util/connection.py
@@ -64,6 +64,12 @@ tcp    ESTAB      0      0              127.0.0.1:22            127.0.0.1:56673
 tcp    ESTAB      0      0           192.168.0.1:44415        38.229.79.2:443    users:(("tor",15843,9))
 """
 
+SS_WHITESPACE_OUTPUT = """\
+Netid  State      Recv-Q Send-Q     Local Address:Port       Peer Address:Port
+tcp    ESTAB      0      0           192.168.0.1:44092      23.112.135.72:443    users:(("tor",15843,10))    
+tcp    ESTAB      0      0           192.168.0.1:44415        38.229.79.2:443    users:(("tor",15843,9))    
+"""
+
 SS_IPV6_OUTPUT = """\
 Netid  State      Recv-Q Send-Q Local Address:Port               Peer Address:Port
 tcp    ESTAB      0      0      5.9.158.75:443                107.170.93.13:56159               users:(("tor",pid=25056,fd=997))
@@ -315,6 +321,19 @@ class TestConnection(unittest.TestCase):
     call_mock.side_effect = OSError('Unable to call ss')
     self.assertRaises(OSError, stem.util.connection.get_connections, Resolver.SS, process_pid = 1111)
 
+  @patch('stem.util.system.call', Mock(return_value = SS_WHITESPACE_OUTPUT.split('\n')))
+  def test_get_connections_by_ss_with_whitespace(self):
+    """
+    On some platforms the 'ss' command pads its lines with trailing whitespace.
+    """
+
+    expected = [
+      Connection('192.168.0.1', 44092, '23.112.135.72', 443, 'tcp', False),
+      Connection('192.168.0.1', 44415, '38.229.79.2', 443, 'tcp', False),
+    ]
+
+    self.assertEqual(expected, stem.util.connection.get_connections(Resolver.SS, process_pid = 15843, process_name = 'tor'))
+
   @patch('stem.util.system.call', Mock(return_value = SS_IPV6_OUTPUT.split('\n')))
   def test_get_connections_by_ss_ipv6(self):
     """