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lint.py
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lint.py
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"""
Check the given capa rules for style issues.
Usage:
$ python scripts/lint.py rules/
Copyright (C) 2020 Mandiant, Inc. All Rights Reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at: [package root]/LICENSE.txt
Unless required by applicable law or agreed to in writing, software distributed under the License
is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and limitations under the License.
"""
import gc
import os
import re
import sys
import json
import time
import string
import difflib
import hashlib
import logging
import argparse
import itertools
import posixpath
from typing import Set, Dict, List
from pathlib import Path
from dataclasses import field, dataclass
import tqdm
import pydantic
import termcolor
import ruamel.yaml
import tqdm.contrib.logging
import capa.main
import capa.rules
import capa.engine
import capa.loader
import capa.helpers
import capa.features.insn
import capa.capabilities.common
from capa.rules import Rule, RuleSet
from capa.features.common import OS_AUTO, String, Feature, Substring
from capa.render.result_document import RuleMetadata
logger = logging.getLogger("lint")
def red(s):
return termcolor.colored(s, "red")
def orange(s):
return termcolor.colored(s, "yellow")
def green(s):
return termcolor.colored(s, "green")
@dataclass
class Context:
"""
attributes:
samples: mapping from content hash (MD5, SHA, etc.) to file path.
rules: rules to inspect
is_thorough: should inspect long-running lints
capabilities_by_sample: cache of results, indexed by file path.
"""
samples: Dict[str, Path]
rules: RuleSet
is_thorough: bool
capabilities_by_sample: Dict[Path, Set[str]] = field(default_factory=dict)
class Lint:
WARN = orange("WARN")
FAIL = red("FAIL")
name = "lint"
level = FAIL
recommendation = ""
def check_rule(self, ctx: Context, rule: Rule):
return False
class NameCasing(Lint):
name = "rule name casing"
recommendation = "Rename rule using to start with lower case letters"
def check_rule(self, ctx: Context, rule: Rule):
return rule.name[0] in string.ascii_uppercase and rule.name[1] not in string.ascii_uppercase
class FilenameDoesntMatchRuleName(Lint):
name = "filename doesn't match the rule name"
recommendation = "Rename rule file to match the rule name"
recommendation_template = 'Rename rule file to match the rule name, expected: "{:s}", found: "{:s}"'
def check_rule(self, ctx: Context, rule: Rule):
expected = rule.name
expected = expected.lower()
expected = expected.replace(".net", "dotnet")
expected = expected.replace(" ", "-")
expected = expected.replace("(", "")
expected = expected.replace(")", "")
expected = expected.replace("+", "")
expected = expected.replace("/", "")
expected = expected.replace(".", "")
expected = expected + ".yml"
found = Path(rule.meta["capa/path"]).name
self.recommendation = self.recommendation_template.format(expected, found)
return expected != found
class MissingNamespace(Lint):
name = "missing rule namespace"
recommendation = "Add meta.namespace so that the rule is emitted correctly"
def check_rule(self, ctx: Context, rule: Rule):
return (
"namespace" not in rule.meta
and not is_nursery_rule(rule)
and "maec/malware-category" not in rule.meta
and "lib" not in rule.meta
)
class NamespaceDoesntMatchRulePath(Lint):
name = "file path doesn't match rule namespace"
recommendation = "Move rule to appropriate directory or update the namespace"
def check_rule(self, ctx: Context, rule: Rule):
# let the other lints catch namespace issues
if "namespace" not in rule.meta:
return False
if is_nursery_rule(rule):
return False
if "maec/malware-category" in rule.meta:
return False
if "lib" in rule.meta:
return False
return rule.meta["namespace"] not in get_normpath(rule.meta["capa/path"])
class MissingScopes(Lint):
name = "missing scopes"
recommendation = (
"Add meta.scopes with both the static (meta.scopes.static) and dynamic (meta.scopes.dynamic) scopes"
)
def check_rule(self, ctx: Context, rule: Rule):
return "scopes" not in rule.meta
class MissingStaticScope(Lint):
name = "missing static scope"
recommendation = "Add a static scope for the rule (file, function, basic block, instruction, or unsupported)"
def check_rule(self, ctx: Context, rule: Rule):
return "static" not in rule.meta.get("scopes")
class MissingDynamicScope(Lint):
name = "missing dynamic scope"
recommendation = "Add a dynamic scope for the rule (file, process, thread, call, or unsupported)"
def check_rule(self, ctx: Context, rule: Rule):
return "dynamic" not in rule.meta.get("scopes")
class InvalidStaticScope(Lint):
name = "invalid static scope"
recommendation = "For the static scope, use either: file, function, basic block, instruction, or unsupported"
def check_rule(self, ctx: Context, rule: Rule):
return rule.meta.get("scopes").get("static") not in (
"file",
"function",
"basic block",
"instruction",
"unsupported",
)
class InvalidDynamicScope(Lint):
name = "invalid static scope"
recommendation = "For the dynamic scope, use either: file, process, thread, call, or unsupported"
def check_rule(self, ctx: Context, rule: Rule):
return rule.meta.get("scopes").get("dynamic") not in (
"file",
"process",
"thread",
"call",
"unsupported",
)
class InvalidScopes(Lint):
name = "invalid scopes"
recommendation = "At least one scope (static or dynamic) must be specified"
def check_rule(self, ctx: Context, rule: Rule):
return (rule.meta.get("scopes").get("static") == "unsupported") and (
rule.meta.get("scopes").get("dynamic") == "unsupported"
)
class MissingAuthors(Lint):
name = "missing authors"
recommendation = "Add meta.authors so that users know who to contact with questions"
def check_rule(self, ctx: Context, rule: Rule):
return "authors" not in rule.meta
class MissingExamples(Lint):
name = "missing examples"
recommendation = "Add meta.examples so that the rule can be tested and verified"
def check_rule(self, ctx: Context, rule: Rule):
return (
"examples" not in rule.meta
or not isinstance(rule.meta["examples"], list)
or len(rule.meta["examples"]) == 0
or rule.meta["examples"] == [None]
)
class MissingExampleOffset(Lint):
name = "missing example offset"
recommendation = "Add offset of example function"
def check_rule(self, ctx: Context, rule: Rule):
if rule.meta.get("scope") in ("function", "basic block"):
examples = rule.meta.get("examples")
if isinstance(examples, list):
for example in examples:
if example and ":" not in example:
logger.debug("example: %s", example)
return True
class ExampleFileDNE(Lint):
name = "referenced example doesn't exist"
recommendation = "Add the referenced example to samples directory ($capa-root/tests/data or supplied via --samples)"
def check_rule(self, ctx: Context, rule: Rule):
if not rule.meta.get("examples"):
# let the MissingExamples lint catch this case, don't double report.
return False
found = False
for example in rule.meta.get("examples", []):
if example:
example_id = example.partition(":")[0]
if example_id in ctx.samples:
found = True
break
return not found
class IncorrectValueType(Lint):
name = "incorrect value type"
recommendation = "Change value type"
def check_rule(self, ctx: Context, rule: Rule):
try:
_ = RuleMetadata.from_capa(rule)
except pydantic.ValidationError as e:
self.recommendation = str(e).strip()
return True
return False
class InvalidAttckOrMbcTechnique(Lint):
name = "att&ck/mbc entry is malformed or does not exist"
recommendation = """
The att&ck and mbc fields must respect the following format:
<Tactic/Objective>::<Technique/Behavior> [<ID>]
OR
<Tactic/Objective>::<Technique/Behavior>::<Subtechnique/Method> [<ID.SubID>]
"""
def __init__(self):
super().__init__()
try:
data_path = Path(__file__).resolve().parent / "linter-data.json"
with data_path.open("rb") as fd:
self.data = json.load(fd)
self.enabled_frameworks = self.data.keys()
except (FileNotFoundError, json.decoder.JSONDecodeError):
# linter-data.json missing, or JSON error: log an error and skip this lint
logger.warning(
"Could not load 'scripts/linter-data.json'. The att&ck and mbc information will not be linted."
)
self.enabled_frameworks = []
# This regex matches the format defined in the recommendation attribute
self.reg = re.compile(r"^([\w\s-]+)::(.+) \[([A-Za-z0-9.]+)\]$")
def _entry_check(self, framework, category, entry, eid):
if category not in self.data[framework].keys():
self.recommendation = f'Unknown category: "{category}"'
return True
if eid not in self.data[framework][category].keys():
self.recommendation = f"Unknown entry ID: {eid}"
return True
if self.data[framework][category][eid] != entry:
self.recommendation = (
f'{eid} should be associated to entry "{self.data[framework][category][eid]}" instead of "{entry}"'
)
return True
return False
def check_rule(self, ctx: Context, rule: Rule):
for framework in self.enabled_frameworks:
if framework in rule.meta:
for r in rule.meta[framework]:
m = self.reg.match(r)
if m is None:
return True
args = m.group(1, 2, 3)
if self._entry_check(framework, *args):
return True
return False
DEFAULT_SIGNATURES = capa.main.get_default_signatures()
def get_sample_capabilities(ctx: Context, path: Path) -> Set[str]:
nice_path = path.resolve().absolute()
if path in ctx.capabilities_by_sample:
logger.debug("found cached results: %s: %d capabilities", nice_path, len(ctx.capabilities_by_sample[path]))
return ctx.capabilities_by_sample[path]
logger.debug("analyzing sample: %s", nice_path)
args = argparse.Namespace(input_file=nice_path, format=capa.main.FORMAT_AUTO, backend=capa.main.BACKEND_AUTO)
format_ = capa.main.get_input_format_from_cli(args)
backend = capa.main.get_backend_from_cli(args, format_)
extractor = capa.loader.get_extractor(
nice_path,
format_,
OS_AUTO,
backend,
DEFAULT_SIGNATURES,
should_save_workspace=False,
disable_progress=True,
)
capabilities, _ = capa.capabilities.common.find_capabilities(ctx.rules, extractor, disable_progress=True)
# mypy doesn't seem to be happy with the MatchResults type alias & set(...keys())?
# so we ignore a few types here.
capabilities = set(capabilities.keys()) # type: ignore
assert isinstance(capabilities, set)
logger.debug("computed results: %s: %d capabilities", nice_path, len(capabilities))
ctx.capabilities_by_sample[path] = capabilities
# when i (wb) run the linter in thorough mode locally,
# the OS occasionally kills the process due to memory usage.
# so, be extra aggressive in keeping memory usage down.
#
# tbh, im not sure this actually does anything, but maybe it helps?
gc.collect()
return capabilities
class DoesntMatchExample(Lint):
name = "doesn't match on referenced example"
recommendation = "Fix the rule logic or provide a different example"
def check_rule(self, ctx: Context, rule: Rule):
if not ctx.is_thorough:
return False
examples = rule.meta.get("examples", [])
if not examples:
return False
for example in examples:
example_id = example.partition(":")[0]
try:
path = ctx.samples[example_id]
except KeyError:
# lint ExampleFileDNE will catch this.
# don't double report.
continue
try:
capabilities = get_sample_capabilities(ctx, path)
except Exception as e:
logger.exception("failed to extract capabilities: %s %s %s", rule.name, path, e)
return True
if rule.name not in capabilities:
return True
class StatementWithSingleChildStatement(Lint):
name = "rule contains one or more statements with a single child statement"
recommendation = "remove the superfluous parent statement"
recommendation_template = "remove the superfluous parent statement: {:s}"
violation = False
def check_rule(self, ctx: Context, rule: Rule):
self.violation = False
def rec(statement, is_root=False):
if isinstance(statement, (capa.engine.And, capa.engine.Or)):
children = list(statement.get_children())
if not is_root and len(children) == 1 and isinstance(children[0], capa.engine.Statement):
self.recommendation = self.recommendation_template.format(str(statement))
self.violation = True
for child in children:
rec(child)
rec(rule.statement, is_root=True)
return self.violation
class OrStatementWithAlwaysTrueChild(Lint):
name = "rule contains an `or` statement that's always True because of an `optional` or other child statement that's always True"
recommendation = "clarify the rule logic, e.g. by moving the always True child statement"
recommendation_template = "clarify the rule logic, e.g. by moving the always True child statement: {:s}"
violation = False
def check_rule(self, ctx: Context, rule: Rule):
self.violation = False
def rec(statement):
if isinstance(statement, capa.engine.Or):
children = list(statement.get_children())
for child in children:
# `Some` implements `optional` which is an alias for `0 or more`
if isinstance(child, capa.engine.Some) and child.count == 0:
self.recommendation = self.recommendation_template.format(str(child))
self.violation = True
rec(child)
rec(rule.statement)
return self.violation
class NotNotUnderAnd(Lint):
name = "rule contains a `not` statement that's not found under an `and` statement"
recommendation = "clarify the rule logic and ensure `not` is always found under `and`"
violation = False
def check_rule(self, ctx: Context, rule: Rule):
self.violation = False
def rec(statement):
if isinstance(statement, capa.engine.Statement):
if not isinstance(statement, capa.engine.And):
for child in statement.get_children():
if isinstance(child, capa.engine.Not):
self.violation = True
for child in statement.get_children():
rec(child)
rec(rule.statement)
return self.violation
class OptionalNotUnderAnd(Lint):
name = "rule contains an `optional` or `0 or more` statement that's not found under an `and` statement"
recommendation = "clarify the rule logic and ensure `optional` and `0 or more` is always found under `and`"
violation = False
def check_rule(self, ctx: Context, rule: Rule):
self.violation = False
def rec(statement):
if isinstance(statement, capa.engine.Statement):
if not isinstance(statement, capa.engine.And):
for child in statement.get_children():
if isinstance(child, capa.engine.Some) and child.count == 0:
self.violation = True
for child in statement.get_children():
rec(child)
rec(rule.statement)
return self.violation
class UnusualMetaField(Lint):
name = "unusual meta field"
recommendation = "Remove the meta field"
recommendation_template = 'Remove the meta field: "{:s}"'
def check_rule(self, ctx: Context, rule: Rule):
for key in rule.meta.keys():
if key in capa.rules.META_KEYS:
continue
if key in capa.rules.HIDDEN_META_KEYS:
continue
self.recommendation = self.recommendation_template.format(key)
return True
return False
class LibRuleNotInLibDirectory(Lint):
name = "lib rule not found in lib directory"
recommendation = "Move the rule to the `lib` subdirectory of the rules path"
def check_rule(self, ctx: Context, rule: Rule):
if is_nursery_rule(rule):
return False
if "lib" not in rule.meta:
return False
return "lib/" not in get_normpath(rule.meta["capa/path"])
class LibRuleHasNamespace(Lint):
name = "lib rule has a namespace"
recommendation = "Remove the namespace from the rule"
def check_rule(self, ctx: Context, rule: Rule):
if "lib" not in rule.meta:
return False
return "namespace" in rule.meta
class FeatureStringTooShort(Lint):
name = "feature string too short"
recommendation = 'capa only extracts strings with length >= 4; will not match on "{:s}"'
def check_features(self, ctx: Context, features: List[Feature]):
for feature in features:
if isinstance(feature, (String, Substring)):
assert isinstance(feature.value, str)
if len(feature.value) < 4:
self.recommendation = self.recommendation.format(feature.value)
return True
return False
class FeatureNegativeNumber(Lint):
name = "feature value is negative"
recommendation = "specify the number's two's complement representation"
recommendation_template = (
"capa treats number features as unsigned values; you may specify the number's two's complement "
+ 'representation; will not match on "{:d}"'
)
def check_features(self, ctx: Context, features: List[Feature]):
for feature in features:
if isinstance(feature, (capa.features.insn.Number,)):
assert isinstance(feature.value, int)
if feature.value < 0:
self.recommendation = self.recommendation_template.format(feature.value)
return True
return False
class FeatureNtdllNtoskrnlApi(Lint):
name = "feature api may overlap with ntdll and ntoskrnl"
level = Lint.WARN
recommendation_template = (
"check if {:s} is exported by both ntdll and ntoskrnl; if true, consider removing {:s} "
+ "module requirement to improve detection"
)
def check_features(self, ctx: Context, features: List[Feature]):
for feature in features:
if isinstance(feature, capa.features.insn.API):
assert isinstance(feature.value, str)
modname, _, impname = feature.value.rpartition(".")
if modname == "ntdll" and impname in (
"LdrGetProcedureAddress",
"LdrLoadDll",
"NtCreateThread",
"NtCreatUserProcess",
"NtLoadDriver",
"NtQueryDirectoryObject",
"NtResumeThread",
"NtSuspendThread",
"NtTerminateProcess",
"NtWriteVirtualMemory",
"RtlGetNativeSystemInformation",
"NtCreateThreadEx",
"NtCreateUserProcess",
"NtOpenDirectoryObject",
"NtQueueApcThread",
"ZwResumeThread",
"ZwSuspendThread",
"ZwWriteVirtualMemory",
"NtCreateProcess",
"ZwCreateThread",
"NtCreateProcessEx",
"ZwCreateThreadEx",
"ZwCreateProcess",
"ZwCreateUserProcess",
"RtlCreateUserProcess",
"NtProtectVirtualMemory",
"NtEnumerateSystemEnvironmentValuesEx",
"NtQuerySystemEnvironmentValueEx",
"NtQuerySystemEnvironmentValue",
):
# ntoskrnl.exe does not export these routines
continue
if modname == "ntoskrnl" and impname in (
"PsGetVersion",
"PsLookupProcessByProcessId",
"KeStackAttachProcess",
"ObfDereferenceObject",
"KeUnstackDetachProcess",
"ExGetFirmwareEnvironmentVariable",
):
# ntdll.dll does not export these routines
continue
if modname in ("ntdll", "ntoskrnl"):
self.recommendation = self.recommendation_template.format(impname, modname)
return True
return False
class FormatSingleEmptyLineEOF(Lint):
name = "EOF format"
recommendation = "end file with a single empty line"
def check_rule(self, ctx: Context, rule: Rule):
if rule.definition.endswith("\n") and not rule.definition.endswith("\n\n"):
return False
return True
class FormatIncorrect(Lint):
name = "rule format incorrect"
recommendation_template = "use scripts/capafmt.py or adjust as follows\n{:s}"
def check_rule(self, ctx: Context, rule: Rule):
# EOL depends on Git and our .gitattributes defines text=auto (Git handles files it thinks is best)
# we prefer LF only, but enforcing across OSs seems tedious and unnecessary
actual = rule.definition.replace("\r\n", "\n")
expected = capa.rules.Rule.from_yaml(rule.definition, use_ruamel=True).to_yaml()
if actual != expected:
diff = difflib.ndiff(actual.splitlines(1), expected.splitlines(True))
recommendation_template = self.recommendation_template
self.recommendation = recommendation_template.format("".join(diff))
return True
return False
class FormatStringQuotesIncorrect(Lint):
name = "rule string quotes incorrect"
def check_rule(self, ctx: Context, rule: Rule):
events = capa.rules.Rule._get_ruamel_yaml_parser().parse(rule.definition)
for key in events:
if isinstance(key, ruamel.yaml.ScalarEvent) and key.value == "string":
value = next(events) # assume value is next event
if not isinstance(value, ruamel.yaml.ScalarEvent):
# ignore non-scalar
continue
if value.value.startswith("/") and value.value.endswith(("/", "/i")):
# ignore regex for now
continue
if value.style is None:
# no quotes
self.recommendation = f'add double quotes to "{value.value}"'
return True
if value.style == "'":
# single quote
self.recommendation = f'change single quotes to double quotes for "{value.value}"'
return True
elif isinstance(key, ruamel.yaml.ScalarEvent) and key.value == "substring":
value = next(events) # assume value is next event
if not isinstance(value, ruamel.yaml.ScalarEvent):
# ignore non-scalar
continue
if value.style is None:
# no quotes
self.recommendation = f'add double quotes to "{value.value}"'
return True
if value.style == "'":
# single quote
self.recommendation = f'change single quotes to double quotes for "{value.value}"'
return True
else:
continue
return False
def run_lints(lints, ctx: Context, rule: Rule):
for lint in lints:
if lint.check_rule(ctx, rule):
yield lint
def run_feature_lints(lints, ctx: Context, features: List[Feature]):
for lint in lints:
if lint.check_features(ctx, features):
yield lint
NAME_LINTS = (
NameCasing(),
FilenameDoesntMatchRuleName(),
)
def lint_name(ctx: Context, rule: Rule):
return run_lints(NAME_LINTS, ctx, rule)
SCOPES_LINTS = (
MissingScopes(),
MissingStaticScope(),
MissingDynamicScope(),
InvalidStaticScope(),
InvalidDynamicScope(),
InvalidScopes(),
)
def lint_scope(ctx: Context, rule: Rule):
return run_lints(SCOPES_LINTS, ctx, rule)
META_LINTS = (
MissingNamespace(),
NamespaceDoesntMatchRulePath(),
MissingAuthors(),
MissingExamples(),
MissingExampleOffset(),
ExampleFileDNE(),
UnusualMetaField(),
LibRuleNotInLibDirectory(),
LibRuleHasNamespace(),
InvalidAttckOrMbcTechnique(),
IncorrectValueType(),
)
def lint_meta(ctx: Context, rule: Rule):
return run_lints(META_LINTS, ctx, rule)
FEATURE_LINTS = (FeatureStringTooShort(), FeatureNegativeNumber(), FeatureNtdllNtoskrnlApi())
def lint_features(ctx: Context, rule: Rule):
features = get_features(ctx, rule)
return run_feature_lints(FEATURE_LINTS, ctx, features)
FORMAT_LINTS = (
FormatSingleEmptyLineEOF(),
FormatStringQuotesIncorrect(),
FormatIncorrect(),
)
def lint_format(ctx: Context, rule: Rule):
return run_lints(FORMAT_LINTS, ctx, rule)
def get_normpath(path):
return posixpath.normpath(path).replace(os.sep, "/")
def get_features(ctx: Context, rule: Rule):
# get features from rule and all dependencies including subscopes and matched rules
features = []
namespaces = ctx.rules.rules_by_namespace
deps = [ctx.rules.rules[dep] for dep in rule.get_dependencies(namespaces)]
for r in [rule] + deps:
features.extend(get_rule_features(r))
return features
def get_rule_features(rule):
features = []
def rec(statement):
if isinstance(statement, capa.engine.Statement):
for child in statement.get_children():
rec(child)
else:
features.append(statement)
rec(rule.statement)
return features
LOGIC_LINTS = (
DoesntMatchExample(),
StatementWithSingleChildStatement(),
OrStatementWithAlwaysTrueChild(),
NotNotUnderAnd(),
OptionalNotUnderAnd(),
)
def lint_logic(ctx: Context, rule: Rule):
return run_lints(LOGIC_LINTS, ctx, rule)
def is_nursery_rule(rule):
"""
The nursery is a spot for rules that have not yet been fully polished.
For example, they may not have references to public example of a technique.
Yet, we still want to capture and report on their matches.
"""
return rule.meta.get("capa/nursery")
def lint_rule(ctx: Context, rule: Rule):
logger.debug(rule.name)
violations = list(
itertools.chain(
lint_name(ctx, rule),
lint_scope(ctx, rule),
lint_meta(ctx, rule),
lint_logic(ctx, rule),
lint_features(ctx, rule),
lint_format(ctx, rule),
)
)
if len(violations) > 0:
# don't show nursery rules with a single violation: needs examples.
# this is by far the most common reason to be in the nursery,
# and ends up just producing a lot of noise.
if not (is_nursery_rule(rule) and len(violations) == 1 and violations[0].name == "missing examples"):
print("")
print(f'{" (nursery) " if is_nursery_rule(rule) else ""} {rule.name}')
for violation in violations:
print(
f"{' ' if is_nursery_rule(rule) else ''} {Lint.WARN if is_nursery_rule(rule) else violation.level}: {violation.name}: {violation.recommendation}"
)
print("")
if is_nursery_rule(rule):
has_examples = not any(v.level == Lint.FAIL and v.name == "missing examples" for v in violations)
lints_failed = len(
tuple(
filter(
lambda v: v.level == Lint.FAIL
and not (v.name == "missing examples" or v.name == "referenced example doesn't exist"),
violations,
)
)
)
lints_warned = len(
tuple(
filter(
lambda v: v.level == Lint.WARN
or (v.level == Lint.FAIL and v.name == "referenced example doesn't exist"),
violations,
)
)
)
if (not lints_failed) and (not lints_warned) and has_examples:
print("")
print(f'{" (nursery) " if is_nursery_rule(rule) else ""} {rule.name}')
print(f" {Lint.WARN}: {green('no lint failures')}: Graduate the rule")
print("")
else:
lints_failed = len(tuple(filter(lambda v: v.level == Lint.FAIL, violations)))
lints_warned = len(tuple(filter(lambda v: v.level == Lint.WARN, violations)))
return (lints_failed, lints_warned)
def width(s, count):
if len(s) > count:
return s[: count - 3] + "..."
else:
return s.ljust(count)
def lint(ctx: Context):
"""
Returns: Dict[string, Tuple(int, int)]
- # lints failed
- # lints warned
"""
ret = {}
source_rules = [rule for rule in ctx.rules.rules.values() if not rule.is_subscope_rule()]
with tqdm.contrib.logging.tqdm_logging_redirect(source_rules, unit="rule", leave=False) as pbar:
with capa.helpers.redirecting_print_to_tqdm(False):
for rule in pbar:
name = rule.name
pbar.set_description(width(f"linting rule: {name}", 48))
ret[name] = lint_rule(ctx, rule)
return ret
def collect_samples(samples_path: Path) -> Dict[str, Path]:
"""
recurse through the given path, collecting all file paths, indexed by their content sha256, md5, and filename.
"""
samples = {}
for path in samples_path.rglob("*"):
if path.suffix in [".viv", ".idb", ".i64", ".frz", ".fnames"]:
continue
try:
buf = path.read_bytes()
except IOError:
continue
sha256 = hashlib.sha256()
sha256.update(buf)
md5 = hashlib.md5()
md5.update(buf)
samples[sha256.hexdigest().lower()] = path
samples[sha256.hexdigest().upper()] = path
samples[md5.hexdigest().lower()] = path
samples[md5.hexdigest().upper()] = path
samples[path.name] = path
return samples
def main(argv=None):
if argv is None:
argv = sys.argv[1:]
default_samples_path = str(Path(__file__).resolve().parent.parent / "tests" / "data")
parser = argparse.ArgumentParser(description="Lint capa rules.")
capa.main.install_common_args(parser, wanted={"tag"})
parser.add_argument("rules", type=str, action="append", help="Path to rules")
parser.add_argument("--samples", type=str, default=default_samples_path, help="Path to samples")
parser.add_argument(
"--thorough",
action="store_true",
help="Enable thorough linting - takes more time, but does a better job",
)
args = parser.parse_args(args=argv)
try:
capa.main.handle_common_args(args)
except capa.main.ShouldExitError as e:
return e.status_code
if args.debug:
logging.getLogger("capa").setLevel(logging.DEBUG)
logging.getLogger("viv_utils").setLevel(logging.DEBUG)
else:
logging.getLogger("capa").setLevel(logging.ERROR)
logging.getLogger("viv_utils").setLevel(logging.ERROR)
time0 = time.time()
try:
rules = capa.main.get_rules_from_cli(args)
except capa.main.ShouldExitError as e:
return e.status_code
logger.info("collecting potentially referenced samples")
samples_path = Path(args.samples)