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Fixing security bugs for CVE-2016-9587

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This commit is contained in:
James Cammarata 2016-12-13 11:14:47 -06:00
parent 258c6ada52
commit a6fff93967
7 changed files with 129 additions and 47 deletions
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9
lib/ansible/playbook/conditional.py
View file

@ -28,8 +28,10 @@ from ansible.errors import AnsibleError, AnsibleUndefinedVariable
from ansible.playbook.attribute import FieldAttribute
from ansible.template import Templar
from ansible.module_utils._text import to_native
from ansible.vars.unsafe_proxy import wrap_var
DEFINED_REGEX = re.compile(r'(hostvars\[.+\]|[\w_]+)\s+(not\s+is|is|is\s+not)\s+(defined|undefined)')
LOOKUP_REGEX = re.compile(r'lookup\s*\(')
class Conditional:
@ -127,9 +129,12 @@ class Conditional:
return conditional
# a Jinja2 evaluation that results in something Python can eval!
if hasattr(conditional, '__UNSAFE__') and LOOKUP_REGEX.match(conditional):
raise AnsibleError("The conditional '%s' contains variables which came from an unsafe " \
"source and also contains a lookup() call, failing conditional check" % conditional)
presented = "{%% if %s %%} True {%% else %%} False {%% endif %%}" % conditional
conditional = templar.template(presented)
val = conditional.strip()
val = templar.template(presented).strip()
if val == "True":
return True
elif val == "False":

32
lib/ansible/plugins/action/__init__.py
View file

@ -30,7 +30,7 @@ import time
from abc import ABCMeta, abstractmethod
from ansible import constants as C
from ansible.compat.six import binary_type, text_type, iteritems, with_metaclass
from ansible.compat.six import binary_type, string_types, text_type, iteritems, with_metaclass
from ansible.compat.six.moves import shlex_quote
from ansible.errors import AnsibleError, AnsibleConnectionFailure
from ansible.executor.module_common import modify_module
@ -39,6 +39,7 @@ from ansible.module_utils.json_utils import _filter_non_json_lines
from ansible.parsing.utils.jsonify import jsonify
from ansible.playbook.play_context import MAGIC_VARIABLE_MAPPING
from ansible.release import __version__
from ansible.vars.unsafe_proxy import wrap_var
try:
@ -458,6 +459,8 @@ class ActionBase(with_metaclass(ABCMeta, object)):
# happens sometimes when it is a dir and not on bsd
if 'checksum' not in mystat['stat']:
mystat['stat']['checksum'] = ''
elif not isinstance(mystat['stat']['checksum'], string_types):
raise AnsibleError("Invalid checksum returned by stat: expected a string type but got %s" % type(mystat['stat']['checksum']))
return mystat['stat']
@ -677,16 +680,9 @@ class ActionBase(with_metaclass(ABCMeta, object)):
display.debug("done with _execute_module (%s, %s)" % (module_name, module_args))
return data
def _parse_returned_data(self, res):
try:
filtered_output, warnings = _filter_non_json_lines(res.get('stdout', u''))
for w in warnings:
display.warning(w)
data = json.loads(filtered_output)
data['_ansible_parsed'] = True
if 'ansible_facts' in data and isinstance(data['ansible_facts'], dict):
def _clean_returned_data(self, data):
remove_keys = set()
fact_keys = set(data['ansible_facts'].keys())
fact_keys = set(data.keys())
# first we add all of our magic variable names to the set of
# keys we want to remove from facts
for magic_var in MAGIC_VARIABLE_MAPPING:
@ -715,7 +711,21 @@ class ActionBase(with_metaclass(ABCMeta, object)):
# then we remove them (except for ssh host keys)
for r_key in remove_keys:
if not r_key.startswith('ansible_ssh_host_key_'):
del data['ansible_facts'][r_key]
del data[r_key]
def _parse_returned_data(self, res):
try:
filtered_output, warnings = _filter_non_json_lines(res.get('stdout', u''))
for w in warnings:
display.warning(w)
data = json.loads(filtered_output)
data['_ansible_parsed'] = True
if 'ansible_facts' in data and isinstance(data['ansible_facts'], dict):
self._clean_returned_data(data['ansible_facts'])
data['ansible_facts'] = wrap_var(data['ansible_facts'])
if 'add_host' in data and isinstance(data['add_host'].get('host_vars', None), dict):
self._clean_returned_data(data['add_host']['host_vars'])
data['add_host'] = wrap_var(data['add_host'])
except ValueError:
# not valid json, lets try to capture error
data = dict(failed=True, _ansible_parsed=False)

1
lib/ansible/plugins/action/template.py
View file

@ -23,6 +23,7 @@ import pwd
import time
from ansible import constants as C
from ansible.compat.six import string_types
from ansible.errors import AnsibleError
from ansible.module_utils._text import to_bytes, to_native, to_text
from ansible.module_utils.pycompat24 import get_exception

85
lib/ansible/template/__init__.py
View file

@ -30,8 +30,9 @@ from numbers import Number
from jinja2 import Environment
from jinja2.loaders import FileSystemLoader
from jinja2.exceptions import TemplateSyntaxError, UndefinedError
from jinja2.nodes import EvalContext
from jinja2.utils import concat as j2_concat
from jinja2.runtime import StrictUndefined
from jinja2.runtime import Context, StrictUndefined
from ansible import constants as C
from ansible.compat.six import string_types, text_type
@ -41,7 +42,7 @@ from ansible.template.safe_eval import safe_eval
from ansible.template.template import AnsibleJ2Template
from ansible.template.vars import AnsibleJ2Vars
from ansible.module_utils._text import to_native, to_text
from ansible.vars.unsafe_proxy import UnsafeProxy, wrap_var
try:
from hashlib import sha1
@ -126,6 +127,62 @@ def _count_newlines_from_end(in_str):
# Uncommon cases: zero length string and string containing only newlines
return i
class AnsibleEvalContext(EvalContext):
'''
A custom jinja2 EvalContext, which is currently unused and saved
here for possible future use.
'''
pass
class AnsibleContext(Context):
'''
A custom context, which intercepts resolve() calls and sets a flag
internally if any variable lookup returns an AnsibleUnsafe value. This
flag is checked post-templating, and (when set) will result in the
final templated result being wrapped via UnsafeProxy.
'''
def __init__(self, *args, **kwargs):
super(AnsibleContext, self).__init__(*args, **kwargs)
self.eval_ctx = AnsibleEvalContext(self.environment, self.name)
self.unsafe = False
def _is_unsafe(self, val):
'''
Our helper function, which will also recursively check dict and
list entries due to the fact that they may be repr'd and contain
a key or value which contains jinja2 syntax and would otherwise
lose the AnsibleUnsafe value.
'''
if isinstance(val, dict):
for key in val.keys():
if self._is_unsafe(val[key]):
return True
elif isinstance(val, list):
for item in val:
if self._is_unsafe(item):
return True
elif isinstance(val, string_types) and hasattr(val, '__UNSAFE__'):
return True
return False
def resolve(self, key):
'''
The intercepted resolve(), which uses the helper above to set the
internal flag whenever an unsafe variable value is returned.
'''
val = super(AnsibleContext, self).resolve(key)
if val is not None and not self.unsafe:
if self._is_unsafe(val):
self.unsafe = True
return val
class AnsibleEnvironment(Environment):
'''
Our custom environment, which simply allows us to override the class-level
values for the Template and Context classes used by jinja2 internally.
'''
context_class = AnsibleContext
template_class = AnsibleJ2Template
class Templar:
'''
@ -159,14 +216,13 @@ class Templar:
self._fail_on_filter_errors = True
self._fail_on_undefined_errors = C.DEFAULT_UNDEFINED_VAR_BEHAVIOR
self.environment = Environment(
self.environment = AnsibleEnvironment(
trim_blocks=True,
undefined=StrictUndefined,
extensions=self._get_extensions(),
finalize=self._finalize,
loader=FileSystemLoader(self._basedir),
)
self.environment.template_class = AnsibleJ2Template
self.SINGLE_VAR = re.compile(r"^%s\s*(\w*)\s*%s$" % (self.environment.variable_start_string, self.environment.variable_end_string))
@ -229,7 +285,7 @@ class Templar:
def _clean_data(self, orig_data):
''' remove jinja2 template tags from a string '''
if not isinstance(orig_data, string_types) or hasattr(orig_data, '__ENCRYPTED__'):
if not isinstance(orig_data, string_types) or hasattr(orig_data, '__ENCRYPTED__') or hasattr(orig_data, '__UNSAFE__'):
return orig_data
with contextlib.closing(StringIO(orig_data)) as data:
@ -292,11 +348,12 @@ class Templar:
# Don't template unsafe variables, instead drop them back down to their constituent type.
if hasattr(variable, '__UNSAFE__'):
if isinstance(variable, text_type):
return self._clean_data(variable)
rval = self._clean_data(variable)
else:
# Do we need to convert these into text_type as well?
# return self._clean_data(to_text(variable._obj, nonstring='passthru'))
return self._clean_data(variable._obj)
rval = self._clean_data(variable._obj)
return rval
try:
if convert_bare:
@ -328,14 +385,23 @@ class Templar:
if cache and sha1_hash in self._cached_result:
result = self._cached_result[sha1_hash]
else:
result = self.do_template(variable, preserve_trailing_newlines=preserve_trailing_newlines, escape_backslashes=escape_backslashes, fail_on_undefined=fail_on_undefined, overrides=overrides)
result = self.do_template(
variable,
preserve_trailing_newlines=preserve_trailing_newlines,
escape_backslashes=escape_backslashes,
fail_on_undefined=fail_on_undefined,
overrides=overrides,
)
if convert_data and not self._no_type_regex.match(variable):
# if this looks like a dictionary or list, convert it to such using the safe_eval method
if (result.startswith("{") and not result.startswith(self.environment.variable_start_string)) or \
result.startswith("[") or result in ("True", "False"):
unsafe = hasattr(result, '__UNSAFE__')
eval_results = safe_eval(result, locals=self._available_variables, include_exceptions=True)
if eval_results[1] is None:
result = eval_results[0]
if unsafe:
result = wrap_var(result)
else:
# FIXME: if the safe_eval raised an error, should we do something with it?
pass
@ -435,7 +501,6 @@ class Templar:
ran = None
if ran:
from ansible.vars.unsafe_proxy import UnsafeProxy, wrap_var
if wantlist:
ran = wrap_var(ran)
else:
@ -505,6 +570,8 @@ class Templar:
try:
res = j2_concat(rf)
if new_context.unsafe:
res = wrap_var(res)
except TypeError as te:
if 'StrictUndefined' in to_native(te):
errmsg = "Unable to look up a name or access an attribute in template string (%s).\n" % to_native(data)

2
lib/ansible/template/template.py
View file

@ -33,5 +33,5 @@ class AnsibleJ2Template(jinja2.environment.Template):
'''
def new_context(self, vars=None, shared=False, locals=None):
return jinja2.runtime.Context(self.environment, vars.add_locals(locals), self.name, self.blocks)
return self.environment.context_class(self.environment, vars.add_locals(locals), self.name, self.blocks)

2
lib/ansible/template/vars.py
View file

@ -82,7 +82,7 @@ class AnsibleJ2Vars:
# HostVars is special, return it as-is, as is the special variable
# 'vars', which contains the vars structure
from ansible.vars.hostvars import HostVars
if isinstance(variable, dict) and varname == "vars" or isinstance(variable, HostVars):
if isinstance(variable, dict) and varname == "vars" or isinstance(variable, HostVars) or hasattr(variable, '__UNSAFE__'):
return variable
else:
value = None

3
lib/ansible/vars/unsafe_proxy.py
View file

@ -64,7 +64,6 @@ __all__ = ['UnsafeProxy', 'AnsibleUnsafe', 'AnsibleJSONUnsafeEncoder', 'AnsibleJ
class AnsibleUnsafe(object):
__UNSAFE__ = True
class AnsibleUnsafeText(text_type, AnsibleUnsafe):
pass
@ -101,7 +100,7 @@ class AnsibleJSONUnsafeDecoder(json.JSONDecoder):
def _wrap_dict(v):
for k in v.keys():
if v[k] is not None:
v[k] = wrap_var(v[k])
v[wrap_var(k)] = wrap_var(v[k])
return v