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windows: insert file positioning call between reads and writes...
windows: insert file positioning call between reads and writes fopen() and fdopen() have a unique-to-Windows requirement that transitions between read and write operations in files opened in modes r+, w+, and a+ perform a file positioning call (fsetpos, fseek, or rewind) in between. While the MSDN docs don't say what will happen if this is not done, observations reveal that Python raises an IOError with errno 0. Furthermore, I /think/ this behavior isn't deterministic. But I can reproduce it reliably with subsequent patches applied that open revlogs in a+ mode and perform both reads and writes. This patch introduces a proxy class for file handles opened in r+, w+, and a+ mode on Windows. The class intercepts calls and audits whether a file positioning function has been called between read and write operations. If not, a dummy, no-op seek to the current file position is performed. This appears to be sufficient to "trick" Windows into allowing transitions between read and writes without raising errors.

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sslutil.py
204 lines | 8.3 KiB | text/x-python | PythonLexer
# 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.
from __future__ import absolute_import
import os
import ssl
import sys
from .i18n import _
from . import util
_canloaddefaultcerts = False
try:
ssl_context = ssl.SSLContext
_canloaddefaultcerts = util.safehasattr(ssl_context, 'load_default_certs')
def wrapsocket(sock, keyfile, certfile, ui, cert_reqs=ssl.CERT_NONE,
ca_certs=None, serverhostname=None):
# Allow any version of SSL starting with TLSv1 and
# up. Note that specifying TLSv1 here prohibits use of
# newer standards (like TLSv1_2), so this is the right way
# to do this. Note that in the future it'd be better to
# support using ssl.create_default_context(), which sets
# up a bunch of things in smart ways (strong ciphers,
# protocol versions, etc) and is upgraded by Python
# maintainers for us, but that breaks too many things to
# do it in a hurry.
sslcontext = ssl.SSLContext(ssl.PROTOCOL_SSLv23)
sslcontext.options &= ssl.OP_NO_SSLv2 & ssl.OP_NO_SSLv3
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)
sslcontext.verify_mode = cert_reqs
if ca_certs is not None:
sslcontext.load_verify_locations(cafile=ca_certs)
elif _canloaddefaultcerts:
sslcontext.load_default_certs()
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 util.Abort(_('ssl connection failed'))
return sslsocket
except AttributeError:
def wrapsocket(sock, keyfile, certfile, ui, cert_reqs=ssl.CERT_NONE,
ca_certs=None, serverhostname=None):
sslsocket = ssl.wrap_socket(sock, keyfile, certfile,
cert_reqs=cert_reqs, ca_certs=ca_certs,
ssl_version=ssl.PROTOCOL_TLSv1)
# check if wrap_socket failed silently because socket had been
# closed
# - see http://bugs.python.org/issue13721
if not sslsocket.cipher():
raise util.Abort(_('ssl connection failed'))
return sslsocket
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
if certnames:
return _('certificate is for %s') % ', '.join(certnames)
# 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.
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
"""
if sys.platform != 'darwin' or util.mainfrozen() or not sys.executable:
return False
exe = os.path.realpath(sys.executable).lower()
return (exe.startswith('/usr/bin/python') or
exe.startswith('/system/library/frameworks/python.framework/'))
def _defaultcacerts():
"""return path to CA certificates; None for system's store; ! to disable"""
if _plainapplepython():
dummycert = os.path.join(os.path.dirname(__file__), 'dummycert.pem')
if os.path.exists(dummycert):
return dummycert
if _canloaddefaultcerts:
return None
return '!'
def sslkwargs(ui, host):
kws = {'ui': ui}
hostfingerprint = ui.config('hostfingerprints', host)
if hostfingerprint:
return kws
cacerts = ui.config('web', 'cacerts')
if cacerts == '!':
pass
elif cacerts:
cacerts = util.expandpath(cacerts)
if not os.path.exists(cacerts):
raise util.Abort(_('could not find web.cacerts: %s') % cacerts)
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 != '!':
kws.update({'ca_certs': cacerts,
'cert_reqs': ssl.CERT_REQUIRED,
})
return kws
class validator(object):
def __init__(self, ui, host):
self.ui = ui
self.host = host
def __call__(self, sock, strict=False):
host = self.host
cacerts = self.ui.config('web', 'cacerts')
hostfingerprint = self.ui.config('hostfingerprints', host)
if not sock.cipher(): # work around http://bugs.python.org/issue13721
raise util.Abort(_('%s ssl connection error') % host)
try:
peercert = sock.getpeercert(True)
peercert2 = sock.getpeercert()
except AttributeError:
raise util.Abort(_('%s ssl connection error') % host)
if not peercert:
raise util.Abort(_('%s certificate error: '
'no certificate received') % host)
peerfingerprint = util.sha1(peercert).hexdigest()
nicefingerprint = ":".join([peerfingerprint[x:x + 2]
for x in xrange(0, len(peerfingerprint), 2)])
if hostfingerprint:
if peerfingerprint.lower() != \
hostfingerprint.replace(':', '').lower():
raise util.Abort(_('certificate for %s has unexpected '
'fingerprint %s') % (host, nicefingerprint),
hint=_('check hostfingerprint configuration'))
self.ui.debug('%s certificate matched fingerprint %s\n' %
(host, nicefingerprint))
elif cacerts != '!':
msg = _verifycert(peercert2, host)
if msg:
raise util.Abort(_('%s certificate error: %s') % (host, msg),
hint=_('configure hostfingerprint %s or use '
'--insecure to connect insecurely') %
nicefingerprint)
self.ui.debug('%s certificate successfully verified\n' % host)
elif strict:
raise util.Abort(_('%s certificate with fingerprint %s not '
'verified') % (host, nicefingerprint),
hint=_('check hostfingerprints or web.cacerts '
'config setting'))
else:
self.ui.warn(_('warning: %s certificate with fingerprint %s not '
'verified (check hostfingerprints or web.cacerts '
'config setting)\n') %
(host, nicefingerprint))