sslutil.py
317 lines
| 11.8 KiB
| text/x-python
|
PythonLexer
/ mercurial / sslutil.py
|
r14204 | # sslutil.py - SSL handling for mercurial | ||
# | ||||
# Copyright 2005, 2006, 2007, 2008 Matt Mackall <mpm@selenic.com> | ||||
# Copyright 2006, 2007 Alexis S. L. Carvalho <alexis@cecm.usp.br> | ||||
# Copyright 2006 Vadim Gelfer <vadim.gelfer@gmail.com> | ||||
# | ||||
# This software may be used and distributed according to the terms of the | ||||
# GNU General Public License version 2 or any later version. | ||||
|
r25977 | |||
from __future__ import absolute_import | ||||
|
r14204 | |||
|
r25977 | import os | ||
import ssl | ||||
import sys | ||||
from .i18n import _ | ||||
|
r28577 | from . import ( | ||
error, | ||||
util, | ||||
) | ||||
|
r24291 | |||
|
r28647 | # Python 2.7.9+ overhauled the built-in SSL/TLS features of Python. It added | ||
# support for TLS 1.1, TLS 1.2, SNI, system CA stores, etc. These features are | ||||
# all exposed via the "ssl" module. | ||||
# | ||||
# Depending on the version of Python being used, SSL/TLS support is either | ||||
# modern/secure or legacy/insecure. Many operations in this module have | ||||
# separate code paths depending on support in Python. | ||||
|
r26622 | hassni = getattr(ssl, 'HAS_SNI', False) | ||
|
r28648 | try: | ||
OP_NO_SSLv2 = ssl.OP_NO_SSLv2 | ||||
OP_NO_SSLv3 = ssl.OP_NO_SSLv3 | ||||
except AttributeError: | ||||
OP_NO_SSLv2 = 0x1000000 | ||||
OP_NO_SSLv3 = 0x2000000 | ||||
|
r28649 | try: | ||
# ssl.SSLContext was added in 2.7.9 and presence indicates modern | ||||
# SSL/TLS features are available. | ||||
SSLContext = ssl.SSLContext | ||||
modernssl = True | ||||
|
r28650 | _canloaddefaultcerts = util.safehasattr(SSLContext, 'load_default_certs') | ||
|
r28649 | except AttributeError: | ||
modernssl = False | ||||
|
r28650 | _canloaddefaultcerts = False | ||
|
r28649 | |||
# We implement SSLContext using the interface from the standard library. | ||||
class SSLContext(object): | ||||
# ssl.wrap_socket gained the "ciphers" named argument in 2.7. | ||||
_supportsciphers = sys.version_info >= (2, 7) | ||||
def __init__(self, protocol): | ||||
# From the public interface of SSLContext | ||||
self.protocol = protocol | ||||
self.check_hostname = False | ||||
self.options = 0 | ||||
self.verify_mode = ssl.CERT_NONE | ||||
# Used by our implementation. | ||||
self._certfile = None | ||||
self._keyfile = None | ||||
self._certpassword = None | ||||
self._cacerts = None | ||||
self._ciphers = None | ||||
def load_cert_chain(self, certfile, keyfile=None, password=None): | ||||
self._certfile = certfile | ||||
self._keyfile = keyfile | ||||
self._certpassword = password | ||||
def load_default_certs(self, purpose=None): | ||||
pass | ||||
def load_verify_locations(self, cafile=None, capath=None, cadata=None): | ||||
if capath: | ||||
raise error.Abort('capath not supported') | ||||
if cadata: | ||||
raise error.Abort('cadata not supported') | ||||
self._cacerts = cafile | ||||
def set_ciphers(self, ciphers): | ||||
if not self._supportsciphers: | ||||
raise error.Abort('setting ciphers not supported') | ||||
self._ciphers = ciphers | ||||
def wrap_socket(self, socket, server_hostname=None, server_side=False): | ||||
# server_hostname is unique to SSLContext.wrap_socket and is used | ||||
# for SNI in that context. So there's nothing for us to do with it | ||||
# in this legacy code since we don't support SNI. | ||||
args = { | ||||
'keyfile': self._keyfile, | ||||
'certfile': self._certfile, | ||||
'server_side': server_side, | ||||
'cert_reqs': self.verify_mode, | ||||
'ssl_version': self.protocol, | ||||
'ca_certs': self._cacerts, | ||||
} | ||||
if self._supportsciphers: | ||||
args['ciphers'] = self._ciphers | ||||
return ssl.wrap_socket(socket, **args) | ||||
|
r28652 | def wrapsocket(sock, keyfile, certfile, ui, cert_reqs=ssl.CERT_NONE, | ||
ca_certs=None, serverhostname=None): | ||||
|
r28653 | """Add SSL/TLS to a socket. | ||
This is a glorified wrapper for ``ssl.wrap_socket()``. It makes sane | ||||
choices based on what security options are available. | ||||
In addition to the arguments supported by ``ssl.wrap_socket``, we allow | ||||
the following additional arguments: | ||||
* serverhostname - The expected hostname of the remote server. If the | ||||
server (and client) support SNI, this tells the server which certificate | ||||
to use. | ||||
""" | ||||
|
r28652 | # Despite its name, PROTOCOL_SSLv23 selects the highest protocol | ||
# that both ends support, including TLS protocols. On legacy stacks, | ||||
# the highest it likely goes in TLS 1.0. On modern stacks, it can | ||||
# support TLS 1.2. | ||||
# | ||||
# The PROTOCOL_TLSv* constants select a specific TLS version | ||||
# only (as opposed to multiple versions). So the method for | ||||
# supporting multiple TLS versions is to use PROTOCOL_SSLv23 and | ||||
# disable protocols via SSLContext.options and OP_NO_* constants. | ||||
# However, SSLContext.options doesn't work unless we have the | ||||
# full/real SSLContext available to us. | ||||
# | ||||
# SSLv2 and SSLv3 are broken. We ban them outright. | ||||
if modernssl: | ||||
protocol = ssl.PROTOCOL_SSLv23 | ||||
else: | ||||
protocol = ssl.PROTOCOL_TLSv1 | ||||
|
r28651 | |||
|
r28652 | # TODO use ssl.create_default_context() on modernssl. | ||
sslcontext = SSLContext(protocol) | ||||
|
r28651 | |||
|
r28652 | # This is a no-op on old Python. | ||
sslcontext.options |= OP_NO_SSLv2 | OP_NO_SSLv3 | ||||
|
r28651 | |||
|
r28848 | # This still works on our fake SSLContext. | ||
sslcontext.verify_mode = cert_reqs | ||||
|
r28652 | if certfile is not None: | ||
def password(): | ||||
f = keyfile or certfile | ||||
return ui.getpass(_('passphrase for %s: ') % f, '') | ||||
sslcontext.load_cert_chain(certfile, keyfile, password) | ||||
|
r28848 | |||
|
r28652 | if ca_certs is not None: | ||
sslcontext.load_verify_locations(cafile=ca_certs) | ||||
else: | ||||
# This is a no-op on old Python. | ||||
sslcontext.load_default_certs() | ||||
|
r23834 | |||
|
r28652 | sslsocket = sslcontext.wrap_socket(sock, server_hostname=serverhostname) | ||
# check if wrap_socket failed silently because socket had been | ||||
# closed | ||||
# - see http://bugs.python.org/issue13721 | ||||
if not sslsocket.cipher(): | ||||
raise error.Abort(_('ssl connection failed')) | ||||
return sslsocket | ||||
|
r14204 | |||
def _verifycert(cert, hostname): | ||||
'''Verify that cert (in socket.getpeercert() format) matches hostname. | ||||
CRLs is not handled. | ||||
Returns error message if any problems are found and None on success. | ||||
''' | ||||
if not cert: | ||||
return _('no certificate received') | ||||
dnsname = hostname.lower() | ||||
def matchdnsname(certname): | ||||
return (certname == dnsname or | ||||
'.' in dnsname and certname == '*.' + dnsname.split('.', 1)[1]) | ||||
san = cert.get('subjectAltName', []) | ||||
if san: | ||||
certnames = [value.lower() for key, value in san if key == 'DNS'] | ||||
for name in certnames: | ||||
if matchdnsname(name): | ||||
return None | ||||
|
r14666 | if certnames: | ||
return _('certificate is for %s') % ', '.join(certnames) | ||||
|
r14204 | |||
# subject is only checked when subjectAltName is empty | ||||
for s in cert.get('subject', []): | ||||
key, value = s[0] | ||||
if key == 'commonName': | ||||
try: | ||||
# 'subject' entries are unicode | ||||
certname = value.lower().encode('ascii') | ||||
except UnicodeEncodeError: | ||||
return _('IDN in certificate not supported') | ||||
if matchdnsname(certname): | ||||
return None | ||||
return _('certificate is for %s') % certname | ||||
return _('no commonName or subjectAltName found in certificate') | ||||
# CERT_REQUIRED means fetch the cert from the server all the time AND | ||||
# validate it against the CA store provided in web.cacerts. | ||||
|
r23042 | def _plainapplepython(): | ||
"""return true if this seems to be a pure Apple Python that | ||||
* is unfrozen and presumably has the whole mercurial module in the file | ||||
system | ||||
* presumably is an Apple Python that uses Apple OpenSSL which has patches | ||||
for using system certificate store CAs in addition to the provided | ||||
cacerts file | ||||
""" | ||||
|
r24614 | if sys.platform != 'darwin' or util.mainfrozen() or not sys.executable: | ||
|
r23042 | return False | ||
|
r24614 | exe = os.path.realpath(sys.executable).lower() | ||
|
r23042 | return (exe.startswith('/usr/bin/python') or | ||
exe.startswith('/system/library/frameworks/python.framework/')) | ||||
|
r24288 | def _defaultcacerts(): | ||
|
r24291 | """return path to CA certificates; None for system's store; ! to disable""" | ||
|
r24288 | if _plainapplepython(): | ||
dummycert = os.path.join(os.path.dirname(__file__), 'dummycert.pem') | ||||
if os.path.exists(dummycert): | ||||
return dummycert | ||||
|
r24291 | if _canloaddefaultcerts: | ||
return None | ||||
|
r24290 | return '!' | ||
|
r24288 | |||
|
r14204 | def sslkwargs(ui, host): | ||
|
r25415 | kws = {'ui': ui} | ||
|
r22574 | hostfingerprint = ui.config('hostfingerprints', host) | ||
if hostfingerprint: | ||||
return kws | ||||
cacerts = ui.config('web', 'cacerts') | ||||
|
r24290 | if cacerts == '!': | ||
pass | ||||
elif cacerts: | ||||
|
r14204 | cacerts = util.expandpath(cacerts) | ||
if not os.path.exists(cacerts): | ||||
|
r26587 | raise error.Abort(_('could not find web.cacerts: %s') % cacerts) | ||
|
r24290 | else: | ||
cacerts = _defaultcacerts() | ||||
if cacerts and cacerts != '!': | ||||
ui.debug('using %s to enable OS X system CA\n' % cacerts) | ||||
ui.setconfig('web', 'cacerts', cacerts, 'defaultcacerts') | ||||
if cacerts != '!': | ||||
|
r19806 | kws.update({'ca_certs': cacerts, | ||
|
r25432 | 'cert_reqs': ssl.CERT_REQUIRED, | ||
|
r19806 | }) | ||
return kws | ||||
|
r14204 | |||
class validator(object): | ||||
def __init__(self, ui, host): | ||||
self.ui = ui | ||||
self.host = host | ||||
|
r18887 | def __call__(self, sock, strict=False): | ||
|
r14204 | host = self.host | ||
|
r18879 | |||
|
r15816 | if not sock.cipher(): # work around http://bugs.python.org/issue13721 | ||
|
r26587 | raise error.Abort(_('%s ssl connection error') % host) | ||
|
r18879 | try: | ||
peercert = sock.getpeercert(True) | ||||
peercert2 = sock.getpeercert() | ||||
except AttributeError: | ||||
|
r26587 | raise error.Abort(_('%s ssl connection error') % host) | ||
|
r18879 | |||
|
r15817 | if not peercert: | ||
|
r26587 | raise error.Abort(_('%s certificate error: ' | ||
|
r15817 | 'no certificate received') % host) | ||
|
r28850 | |||
# If a certificate fingerprint is pinned, use it and only it to | ||||
# validate the remote cert. | ||||
hostfingerprints = self.ui.configlist('hostfingerprints', host) | ||||
|
r15814 | peerfingerprint = util.sha1(peercert).hexdigest() | ||
nicefingerprint = ":".join([peerfingerprint[x:x + 2] | ||||
for x in xrange(0, len(peerfingerprint), 2)]) | ||||
|
r28525 | if hostfingerprints: | ||
fingerprintmatch = False | ||||
for hostfingerprint in hostfingerprints: | ||||
if peerfingerprint.lower() == \ | ||||
hostfingerprint.replace(':', '').lower(): | ||||
fingerprintmatch = True | ||||
break | ||||
if not fingerprintmatch: | ||||
|
r26587 | raise error.Abort(_('certificate for %s has unexpected ' | ||
|
r15997 | 'fingerprint %s') % (host, nicefingerprint), | ||
hint=_('check hostfingerprint configuration')) | ||||
|
r15815 | self.ui.debug('%s certificate matched fingerprint %s\n' % | ||
(host, nicefingerprint)) | ||||
|
r28850 | return | ||
# No pinned fingerprint. Establish trust by looking at the CAs. | ||||
cacerts = self.ui.config('web', 'cacerts') | ||||
if cacerts != '!': | ||||
|
r18879 | msg = _verifycert(peercert2, host) | ||
|
r14204 | if msg: | ||
|
r26587 | raise error.Abort(_('%s certificate error: %s') % (host, msg), | ||
|
r15814 | hint=_('configure hostfingerprint %s or use ' | ||
'--insecure to connect insecurely') % | ||||
nicefingerprint) | ||||
|
r14204 | self.ui.debug('%s certificate successfully verified\n' % host) | ||
|
r18887 | elif strict: | ||
|
r26587 | raise error.Abort(_('%s certificate with fingerprint %s not ' | ||
|
r18887 | 'verified') % (host, nicefingerprint), | ||
hint=_('check hostfingerprints or web.cacerts ' | ||||
'config setting')) | ||||
|
r14204 | else: | ||
|
r15815 | self.ui.warn(_('warning: %s certificate with fingerprint %s not ' | ||
'verified (check hostfingerprints or web.cacerts ' | ||||
'config setting)\n') % | ||||
(host, nicefingerprint)) | ||||