[stable-2.4] ignore ansible.cfg in world writable cwd (#42070)

* ignore ansible.cfg in world writable cwd
 * also added 'warnings' to config
 * updated man page template.
(cherry picked from commit b6f2aad600)

Co-authored-by: Brian Coca <bcoca@users.noreply.github.com>

CHANGELOG.md

@@ -8,6 +8,8 @@ Ansible Changes By Release
 ### Bugfixes
 * **Security Fix** - avoid loading host/group vars from cwd when not specifying
   a playbook or playbook base dir (https://github.com/ansible/ansible/pull/42067)
+* **Security Fix** - avoid using ansible.cfg in a world readable dir
+  https://github.com/ansible/ansible/pull/42070
 
 
 <a id="2.4.5"></a>

docs/templates/man.j2

@@ -76,17 +76,18 @@ ENVIRONMENT
 The following environment variables may be specified.
 
 {% if inventory %}
-ANSIBLE_INVENTORY  -- Override the default ansible inventory file
+ANSIBLE_INVENTORY  -- Override the default ansible inventory sources
 
 {% endif %}
 {% if library %}
 ANSIBLE_LIBRARY -- Override the default ansible module library path
 
 {% endif %}
-ANSIBLE_CONFIG -- Override the default ansible config file
+ANSIBLE_CONFIG -- Specify override location for the ansible config file
 
 Many more are available for most options in ansible.cfg
 
+For a full list check https://docs.ansible.com/. or use the `ansible-config` command.
 
 FILES
 -----
@@ -99,6 +100,9 @@ FILES
 
 ~/.ansible.cfg -- User config file, overrides the default config if present
 
+./ansible.cfg -- Local config file (in current working direcotry) assumed to be 'project specific' and overrides the rest if present.
+
+As mentioned above, the ANSIBLE_CONFIG environment variable will override all others.
 
 AUTHOR
 ------
@@ -110,8 +114,8 @@ See the AUTHORS file for a complete list of contributors.
 COPYRIGHT
 ---------
 
-Copyright © 2017 Red Hat, Inc | Ansible.
+Copyright © 2018 Red Hat, Inc | Ansible.
-Ansible is released under the terms of the GPLv3 License.
+Ansible is released under the terms of the GPLv3 license.
 
 
 SEE ALSO

lib/ansible/config/manager.py

@@ -7,6 +7,7 @@ __metaclass__ = type
 
 import os
 import sys
+import stat
 import tempfile
 import yaml
 
@@ -134,7 +135,7 @@ def get_ini_config_value(p, entry):
     return value
 
 
-def find_ini_config_file():
+def find_ini_config_file(warnings=None):
     ''' Load INI Config File order(first found is used): ENV, CWD, HOME, /etc/ansible '''
     # FIXME: eventually deprecate ini configs
 
@@ -144,7 +145,14 @@ def find_ini_config_file():
         if os.path.isdir(path0):
             path0 += "/ansible.cfg"
     try:
-        path1 = os.getcwd() + "/ansible.cfg"
+        path1 = os.getcwd()
+        perms1 = os.stat(path1)
+        if perms1.st_mode & stat.S_IWOTH:
+            if warnings is not None:
+                warnings.add("Ansible is in a world writable directory (%s), ignoring it as an ansible.cfg source." % to_text(path1))
+            path1 = None
+        else:
+            path1 += "/ansible.cfg"
     except OSError:
         path1 = None
     path2 = unfrackpath("~/.ansible.cfg", follow=False)
@@ -163,6 +171,7 @@ class ConfigManager(object):
 
     UNABLE = []
     DEPRECATED = []
+    WARNINGS = set()
 
     def __init__(self, conf_file=None):
 
@@ -184,7 +193,7 @@ class ConfigManager(object):
 
         if self._config_file is None:
             # set config using ini
-            self._config_file = find_ini_config_file()
+            self._config_file = find_ini_config_file(self.WARNINGS)
 
         if self._config_file:
             if os.path.exists(self._config_file):

lib/ansible/constants.py

@@ -18,6 +18,16 @@ from ansible.module_utils.six import string_types
 from ansible.config.manager import ConfigManager, ensure_type, get_ini_config_value
 
 
+def _warning(msg):
+    ''' display is not guaranteed here, nor it being the full class, but try anyways, fallback to sys.stderr.write '''
+    try:
+        from __main__ import display
+        display.warning(msg)
+    except:
+        import sys
+        sys.stderr.write(' [WARNING] %s\n' % (msg))
+
+
 def _deprecated(msg):
     ''' display is not guaranteed here, nor it being the full class, but try anyways, fallback to sys.stderr.write '''
     try:
@@ -122,3 +132,6 @@ for setting in config.data.get_settings():
         value = ensure_type(value, setting.name)
 
     set_constant(setting.name, value)
+
+for warn in config.WARNINGS:
+    _warning(warn)