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from __future__ import print_function
import os, sys, json, re
import collections
script_directory = os.path.dirname(os.path.abspath(__file__))
template_directory = os.path.abspath(
os.path.join(script_directory, 'template'))
test_root_directory = os.path.abspath(
os.path.join(script_directory, '..', '..', '..'))
def get_template(basename):
with open(os.path.join(template_directory, basename), "r") as f:
return f.read()
def write_file(filename, contents):
with open(filename, "w") as f:
f.write(contents)
def read_nth_line(fp, line_number):
fp.seek(0)
for i, line in enumerate(fp):
if (i + 1) == line_number:
return line
def load_spec_json(path_to_spec):
re_error_location = re.compile('line ([0-9]+) column ([0-9]+)')
with open(path_to_spec, "r") as f:
try:
return json.load(f, object_pairs_hook=collections.OrderedDict)
except ValueError as ex:
print(ex.message)
match = re_error_location.search(ex.message)
if match:
line_number, column = int(match.group(1)), int(match.group(2))
print(read_nth_line(f, line_number).rstrip())
print(" " * (column - 1) + "^")
sys.exit(1)
class ShouldSkip(Exception):
'''
Raised when the given combination of subresource type, source context type,
delivery type etc. are not supported and we should skip that configuration.
ShouldSkip is expected in normal generator execution (and thus subsequent
generation continues), as we first enumerate a broad range of configurations
first, and later raise ShouldSkip to filter out unsupported combinations.
ShouldSkip is distinguished from other general errors that cause immediate
termination of the generator and require fix.
'''
def __init__(self):
pass
class PolicyDelivery(object):
'''
See `@typedef PolicyDelivery` comments in
`common/security-features/resources/common.sub.js`.
'''
def __init__(self, delivery_type, key, value):
self.delivery_type = delivery_type
self.key = key
self.value = value
@classmethod
def list_from_json(cls, list, target_policy_delivery,
supported_delivery_types):
# type: (dict, PolicyDelivery, typing.List[str]) -> typing.List[PolicyDelivery]
'''
Parses a JSON object `list` that represents a list of `PolicyDelivery`
and returns a list of `PolicyDelivery`, plus supporting placeholders
(see `from_json()` comments below or
`common/security-features/README.md`).
Can raise `ShouldSkip`.
'''
if list is None:
return []
out = []
for obj in list:
policy_delivery = PolicyDelivery.from_json(
obj, target_policy_delivery, supported_delivery_types)
# Drop entries with null values.
if policy_delivery.value is None:
continue
out.append(policy_delivery)
return out
@classmethod
def from_json(cls, obj, target_policy_delivery, supported_delivery_types):
# type: (dict, PolicyDelivery, typing.List[str]) -> PolicyDelivery
'''
Parses a JSON object `obj` and returns a `PolicyDelivery` object.
In addition to dicts (in the same format as to_json() outputs),
this method accepts the following placeholders:
"policy":
`target_policy_delivery`
"policyIfNonNull":
`target_policy_delivery` if its value is not None.
"anotherPolicy":
A PolicyDelivery that has the same key as
`target_policy_delivery` but a different value.
The delivery type is selected from `supported_delivery_types`.
Can raise `ShouldSkip`.
'''
if obj == "policy":
policy_delivery = target_policy_delivery
elif obj == "nonNullPolicy":
if target_policy_delivery.value is None:
raise ShouldSkip()
policy_delivery = target_policy_delivery
elif obj == "anotherPolicy":
policy_delivery = target_policy_delivery.get_another_policy(
supported_delivery_types[0])
elif type(obj) == dict:
policy_delivery = PolicyDelivery(obj['deliveryType'], obj['key'],
obj['value'])
else:
raise Exception('policy delivery is invalid: ' + obj)
# Omit unsupported combinations of source contexts and delivery type.
if policy_delivery.delivery_type not in supported_delivery_types:
raise ShouldSkip()
return policy_delivery
def to_json(self):
# type: () -> dict
return {
"deliveryType": self.delivery_type,
"key": self.key,
"value": self.value
}
def get_another_policy(self, delivery_type):
# type: (str) -> PolicyDelivery
if self.key == 'referrerPolicy':
if self.value == 'no-referrer':
return PolicyDelivery(delivery_type, self.key, 'unsafe-url')
else:
return PolicyDelivery(delivery_type, self.key, 'no-referrer')
else:
raise Exception('delivery key is invalid: ' + self.key)
class SourceContext(object):
def __init__(self, source_context_type, policy_deliveries):
# type: (unicode, typing.List[PolicyDelivery]) -> None
self.source_context_type = source_context_type
self.policy_deliveries = policy_deliveries
@classmethod
def from_json(cls, obj, target_policy_delivery, source_context_schema):
'''
Parses a JSON object `obj` and returns a `SourceContext` object.
`target_policy_delivery` and `source_context_schema` are used for
policy delivery placeholders and filtering out unsupported
delivery types.
Can raise `ShouldSkip`.
'''
source_context_type = obj.get('sourceContextType')
policy_deliveries = PolicyDelivery.list_from_json(
obj.get('policyDeliveries'), target_policy_delivery,
source_context_schema['supported_delivery_type']
[source_context_type])
return SourceContext(source_context_type, policy_deliveries)
def to_json(self):
return {
"sourceContextType": self.source_context_type,
"policyDeliveries": [x.to_json() for x in self.policy_deliveries]
}
class CustomEncoder(json.JSONEncoder):
'''
Used to dump dicts containing `SourceContext`/`PolicyDelivery` into JSON.
'''
def default(self, obj):
if isinstance(obj, SourceContext):
return obj.to_json()
if isinstance(obj, PolicyDelivery):
return obj.to_json()
return json.JSONEncoder.default(self, obj)
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