vscode-python/pythonFiles/jedi/api/environment.py at master · plusls/vscode-python · GitHub

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"""

Environments are a way to activate different Python versions or Virtualenvs for

static analysis. The Python binary in that environment is going to be executed.

"""

import os

import re

import sys

import hashlib

import filecmp

from subprocess import PIPE

from collections import namedtuple

# When dropping Python 2.7 support we should consider switching to

# `shutil.which`.

from distutils.spawn import find_executable

from jedi._compatibility import GeneralizedPopen

from jedi.cache import memoize_method, time_cache

from jedi.evaluate.compiled.subprocess import get_subprocess, \

EvaluatorSameProcess, EvaluatorSubprocess

import parso

_VersionInfo = namedtuple('VersionInfo', 'major minor micro')

_SUPPORTED_PYTHONS = ['3.6', '3.5', '3.4', '3.3', '2.7']

_SAFE_PATHS = ['/usr/bin', '/usr/local/bin']

_CURRENT_VERSION = '%s.%s' % (sys.version_info.major, sys.version_info.minor)

class InvalidPythonEnvironment(Exception):

"""

If you see this exception, the Python executable or Virtualenv you have

been trying to use is probably not a correct Python version.

"""

class _BaseEnvironment(object):

@memoize_method

def get_grammar(self):

version_string = '%s.%s' % (self.version_info.major, self.version_info.minor)

return parso.load_grammar(version=version_string)

@property

def _sha256(self):

try:

return self._hash

except AttributeError:

self._hash = _calculate_sha256_for_file(self.executable)

return self._hash

class Environment(_BaseEnvironment):

"""

This class is supposed to be created by internal Jedi architecture. You

should not create it directly. Please use create_environment or the other

functions instead. It is then returned by that function.

"""

def __init__(self, path, executable):

self.path = os.path.abspath(path)

"""

The path to an environment, matches ``sys.prefix``.

"""

self.executable = os.path.abspath(executable)

"""

The Python executable, matches ``sys.executable``.

"""

self.version_info = self._get_version()

"""

Like ``sys.version_info``. A tuple to show the current Environment's

Python version.

"""

def _get_version(self):

try:

process = GeneralizedPopen([self.executable, '--version'], stdout=PIPE, stderr=PIPE)

stdout, stderr = process.communicate()

retcode = process.poll()

if retcode:

raise InvalidPythonEnvironment()

except OSError:

raise InvalidPythonEnvironment()

# Until Python 3.4 wthe version string is part of stderr, after that

# stdout.

output = stdout + stderr

match = re.match(br'Python (\d+)\.(\d+)\.(\d+)', output)

if match is None:

raise InvalidPythonEnvironment("--version not working")

return _VersionInfo(*[int(m) for m in match.groups()])

def __repr__(self):

version = '.'.join(str(i) for i in self.version_info)

return '<%s: %s in %s>' % (self.__class__.__name__, version, self.path)

def get_evaluator_subprocess(self, evaluator):

return EvaluatorSubprocess(evaluator, self._get_subprocess())

def _get_subprocess(self):

return get_subprocess(self.executable)

@memoize_method

def get_sys_path(self):

"""

The sys path for this environment. Does not include potential

modifications like ``sys.path.append``.

:returns: list of str

"""

# It's pretty much impossible to generate the sys path without actually

# executing Python. The sys path (when starting with -S) itself depends

# on how the Python version was compiled (ENV variables).

# If you omit -S when starting Python (normal case), additionally

# site.py gets executed.

return self._get_subprocess().get_sys_path()

class SameEnvironment(Environment):

def __init__(self):

super(SameEnvironment, self).__init__(sys.prefix, sys.executable)

def _get_version(self):

return _VersionInfo(*sys.version_info[:3])

class InterpreterEnvironment(_BaseEnvironment):

def __init__(self):

self.version_info = _VersionInfo(*sys.version_info[:3])

def get_evaluator_subprocess(self, evaluator):

return EvaluatorSameProcess(evaluator)

def get_sys_path(self):

return sys.path

def _get_virtual_env_from_var():

var = os.environ.get('VIRTUAL_ENV')

if var is not None:

if var == sys.prefix:

return SameEnvironment()

try:

return create_environment(var)

except InvalidPythonEnvironment:

pass

def _calculate_sha256_for_file(path):

sha256 = hashlib.sha256()

with open(path, 'rb') as f:

for block in iter(lambda: f.read(filecmp.BUFSIZE), b''):

sha256.update(block)

return sha256.hexdigest()

def get_default_environment():

"""

Tries to return an active Virtualenv. If there is no VIRTUAL_ENV variable

set it will return the latest Python version installed on the system. This

makes it possible to use as many new Python features as possible when using

autocompletion and other functionality.

:returns: :class:`Environment`

"""

virtual_env = _get_virtual_env_from_var()

if virtual_env is not None:

return virtual_env

for environment in find_system_environments():

return environment

# If no Python Environment is found, use the environment we're already

# using.

return SameEnvironment()

@time_cache(seconds=10 * 60) # 10 Minutes

def get_cached_default_environment():

return get_default_environment()

def find_virtualenvs(paths=None, **kwargs):

"""

:param paths: A list of paths in your file system to be scanned for

Virtualenvs. It will search in these paths and potentially execute the

Python binaries. Also the VIRTUAL_ENV variable will be checked if it

contains a valid Virtualenv.

:param safe: Default True. In case this is False, it will allow this

function to execute potential `python` environments. An attacker might

be able to drop an executable in a path this function is searching by

default. If the executable has not been installed by root, it will not

be executed.

:yields: :class:`Environment`

"""

def py27_comp(paths=None, safe=True):

if paths is None:

paths = []

_used_paths = set()

# Using this variable should be safe, because attackers might be able

# to drop files (via git) but not environment variables.

virtual_env = _get_virtual_env_from_var()

if virtual_env is not None:

yield virtual_env

_used_paths.add(virtual_env.path)

for directory in paths:

if not os.path.isdir(directory):

continue

directory = os.path.abspath(directory)

for path in os.listdir(directory):

path = os.path.join(directory, path)

if path in _used_paths:

# A path shouldn't be evaluated twice.

continue

_used_paths.add(path)

try:

executable = _get_executable_path(path, safe=safe)

yield Environment(path, executable)

except InvalidPythonEnvironment:

pass

return py27_comp(paths, **kwargs)

def find_system_environments():

"""

Ignores virtualenvs and returns the Python versions that were installed on

your system. This might return nothing, if you're running Python e.g. from

a portable version.

The environments are sorted from latest to oldest Python version.

:yields: :class:`Environment`

"""

for version_string in _SUPPORTED_PYTHONS:

try:

yield get_system_environment(version_string)

except InvalidPythonEnvironment:

pass

# TODO: the logic to find the Python prefix is much more complicated than that.

# See Modules/getpath.c for UNIX and PC/getpathp.c for Windows in CPython's

# source code. A solution would be to deduce it by running the Python

# interpreter and printing the value of sys.prefix.

def _get_python_prefix(executable):

if os.name != 'nt':

return os.path.dirname(os.path.dirname(executable))

landmark = os.path.join('Lib', 'os.py')

prefix = os.path.dirname(executable)

while prefix:

if os.path.join(prefix, landmark):

return prefix

prefix = os.path.dirname(prefix)

raise InvalidPythonEnvironment(

"Cannot find prefix of executable %s." % executable)

# TODO: this function should probably return a list of environments since

# multiple Python installations can be found on a system for the same version.

def get_system_environment(version):

"""

Return the first Python environment found for a string of the form 'X.Y'

where X and Y are the major and minor versions of Python.

:raises: :exc:`.InvalidPythonEnvironment`

:returns: :class:`Environment`

"""

exe = find_executable('python' + version)

if exe:

if exe == sys.executable:

return SameEnvironment()

return Environment(_get_python_prefix(exe), exe)

if os.name == 'nt':

for prefix, exe in _get_executables_from_windows_registry(version):

return Environment(prefix, exe)

raise InvalidPythonEnvironment("Cannot find executable python%s." % version)

def create_environment(path, safe=True):

"""

Make it possible to create an environment by hand.

:raises: :exc:`.InvalidPythonEnvironment`

:returns: :class:`Environment`

"""

return Environment(path, _get_executable_path(path, safe=safe))

def _get_executable_path(path, safe=True):

"""

Returns None if it's not actually a virtual env.

"""

if os.name == 'nt':

python = os.path.join(path, 'Scripts', 'python.exe')

else:

python = os.path.join(path, 'bin', 'python')

if not os.path.exists(python):

raise InvalidPythonEnvironment("%s seems to be missing." % python)

if safe and not _is_safe(python):

raise InvalidPythonEnvironment("The python binary is potentially unsafe.")

return python

def _get_executables_from_windows_registry(version):

# The winreg module is named _winreg on Python 2.

try:

import winreg

except ImportError:

import _winreg as winreg

# TODO: support Python Anaconda.

sub_keys = [

r'SOFTWARE\Python\PythonCore\{version}\InstallPath',

r'SOFTWARE\Wow6432Node\Python\PythonCore\{version}\InstallPath',

r'SOFTWARE\Python\PythonCore\{version}-32\InstallPath',

r'SOFTWARE\Wow6432Node\Python\PythonCore\{version}-32\InstallPath'

]

for root_key in [winreg.HKEY_CURRENT_USER, winreg.HKEY_LOCAL_MACHINE]:

for sub_key in sub_keys:

sub_key = sub_key.format(version=version)

try:

with winreg.OpenKey(root_key, sub_key) as key:

prefix = winreg.QueryValueEx(key, '')[0]

exe = os.path.join(prefix, 'python.exe')

if os.path.isfile(exe):

yield prefix, exe

except WindowsError:

pass

def _is_safe(executable_path):

# Resolve sym links. A venv typically is a symlink to a known Python

# binary. Only virtualenvs copy symlinks around.

real_path = os.path.realpath(executable_path)

if _is_unix_safe_simple(real_path):

return True

# Just check the list of known Python versions. If it's not in there,

# it's likely an attacker or some Python that was not properly

# installed in the system.

for environment in find_system_environments():

if environment.executable == real_path:

return True

# If the versions don't match, just compare the binary files. If we

# don't do that, only venvs will be working and not virtualenvs.

# venvs are symlinks while virtualenvs are actual copies of the

# Python files.

# This still means that if the system Python is updated and the

# virtualenv's Python is not (which is probably never going to get

# upgraded), it will not work with Jedi. IMO that's fine, because

# people should just be using venv. ~ dave

if environment._sha256 == _calculate_sha256_for_file(real_path):

return True

return False

def _is_unix_safe_simple(real_path):

if _is_unix_admin():

# In case we are root, just be conservative and

# only execute known paths.

return any(real_path.startswith(p) for p in _SAFE_PATHS)

uid = os.stat(real_path).st_uid

# The interpreter needs to be owned by root. This means that it wasn't

# written by a user and therefore attacking Jedi is not as simple.

# The attack could look like the following:

# 1. A user clones a repository.

# 2. The repository has an innocent looking folder called foobar. jedi

# searches for the folder and executes foobar/bin/python --version if

# there's also a foobar/bin/activate.

# 3. The bin/python is obviously not a python script but a bash script or

# whatever the attacker wants.

return uid == 0

def _is_unix_admin():

try:

return os.getuid() == 0

except AttributeError:

return False # Windows

vscode-python/pythonFiles/jedi/api/environment.py at master · plusls/vscode-python · GitHub

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