Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Handling ini files #13

Merged
merged 3 commits into from
Apr 6, 2018
Merged
Show file tree
Hide file tree
Changes from 2 commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
89 changes: 87 additions & 2 deletions detect_secrets/plugins/high_entropy_strings.py
Original file line number Diff line number Diff line change
Expand Up @@ -3,9 +3,19 @@
import math
import re
import string
from contextlib import contextmanager

from future import standard_library

from .base import BasePlugin
from detect_secrets.core.potential_secret import PotentialSecret
standard_library.install_aliases()
import configparser # noqa: E402


INI_FILE_EXTENSIONS = (
'ini',
)


class HighEntropyStringsPlugin(BasePlugin):
Expand All @@ -22,6 +32,14 @@ def __init__(self, charset, limit, *args):
# TODO: Update for not just python comments?
self.ignore_regex = re.compile(r'# ?pragma: ?whitelist[ -]secret')

def analyze(self, file, filename):
# Heuristically determine whether file is an ini-formatted file.
for ext in INI_FILE_EXTENSIONS:
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

We could maybe run file on them and see if it comes back ASCII text, might get expensive.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

ini styled formats is definitely a subset of ASCII text, so that solution may lead to false positives.

Eg.

$ file test_data/config.ini
test_data/config.ini: ASCII text
$ file test_data/baseline.file
test_data/baseline.file: ASCII text

Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I'm kind of ambivalent, right now it's easier to exclude files than include them in the tuple, which makes me lean towards including more by default/making the false-p/false-n rate customizable. Nothing is really set in stone though, we can always change it in the future.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Good point. Let me jiggle it up a bit.

if filename.endswith('.{}'.format(ext)):
return self._analyze_ini_file(file, filename)

return super(HighEntropyStringsPlugin, self).analyze(file, filename)

def calculate_shannon_entropy(self, data):
"""Returns the entropy of a given string.

Expand Down Expand Up @@ -54,13 +72,49 @@ def analyze_string(self, string, line_num, filename):
# There may be multiple strings on the same line
results = self.regex.findall(string)
for result in results:
entropy_value = self.calculate_shannon_entropy(result[1])
# To accommodate changing self.regex, due to different filetypes
if isinstance(result, tuple):
result = result[1]

entropy_value = self.calculate_shannon_entropy(result)
if entropy_value > self.entropy_limit:
secret = PotentialSecret(self.secret_type, filename, line_num, result[1])
secret = PotentialSecret(self.secret_type, filename, line_num, result)
output[secret] = secret

return output

def _analyze_ini_file(self, file, filename):
"""
:returns: same format as super().analyze()
"""
parser = configparser.ConfigParser()
parser.read_file(file)

potential_secrets = {}

# Hacky way to keep track of line location.
file.seek(0)
lines = list(map(lambda x: x.strip(), file.readlines()))
line_offset = 0

with self._non_quoted_string_regex():
for section_name, _ in parser.items():
for key, value in parser.items(section_name):
# +1, because we don't want to double count lines
offset = self._get_line_offset(key, value, lines) + 1
line_offset += offset
lines = lines[offset:]

secrets = self.analyze_string(
value,
line_offset,
filename,
)

potential_secrets.update(secrets)

return potential_secrets

@property
def __dict__(self):
output = super(HighEntropyStringsPlugin, self).__dict__
Expand All @@ -70,6 +124,37 @@ def __dict__(self):

return output

@contextmanager
def _non_quoted_string_regex(self):
"""For certain file formats, strings need not necessarily follow the
normal convention of being denoted by single or double quotes. In these
cases, we modify the regex accordingly.
"""
old_regex = self.regex
self.regex = re.compile(r'^([%s]+)$' % self.charset)

yield

self.regex = old_regex

@staticmethod
def _get_line_offset(key, value, lines):
"""Returns the index of the location of key, value pair in lines.

:type key: str
:param key: key, in config file.

:type value: str
:param value: value for key, in config file.

:type lines: list
:param lines: a collection of lines-so-far in file
"""
regex = re.compile(r'^{}[ :=]+{}'.format(key, value))
for index, line in enumerate(lines):
if regex.match(line):
return index


class HexHighEntropyString(HighEntropyStringsPlugin):
"""HighEntropyStringsPlugin for hex strings"""
Expand Down
9 changes: 9 additions & 0 deletions test_data/config.ini
Original file line number Diff line number Diff line change
@@ -0,0 +1,9 @@
[credentials]
password = 12345678901234

[parent]
[child]
key = value

[aws]
aws_secret_key = 2345678901
26 changes: 26 additions & 0 deletions tests/plugins/high_entropy_strings_test.py
Original file line number Diff line number Diff line change
Expand Up @@ -104,6 +104,32 @@ def test_ignored_lines(self, content_to_format):

assert len(results) == 0

def test_ini_file(self):
# We're testing two files here, because we want to make sure that
# the HighEntropyStrings regex is reset back to normal after
# scanning the ini file.
filenames = [
'test_data/config.ini',
'test_data/files/file_with_secrets.py',
]

plugin = Base64HighEntropyString(3)

accumulated_secrets = {}
for filename in filenames:
with open(filename) as f:
accumulated_secrets.update(
plugin.analyze(f, filename),
)

for secret in accumulated_secrets.values():
location = str(secret).splitlines()[1]
assert location in (
'Location: test_data/config.ini:2',
'Location: test_data/config.ini:9',
'Location: test_data/files/file_with_secrets.py:3',
)


class TestBase64HighEntropyStrings(HighEntropyStringsTest):

Expand Down