# 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.

import os

from mercurial import util

from mercurial.i18n import _

try:

    # avoid using deprecated/broken FakeSocket in python 2.6

    import ssl

    CERT_REQUIRED = ssl.CERT_REQUIRED

    def ssl_wrap_socket(sock, keyfile, certfile,

                cert_reqs=ssl.CERT_NONE, ca_certs=None):

        sslsocket = ssl.wrap_socket(sock, keyfile, certfile,

                cert_reqs=cert_reqs, ca_certs=ca_certs)

        # 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 ImportError:

    CERT_REQUIRED = 2

    import socket, httplib

    def ssl_wrap_socket(sock, key_file, cert_file,

                        cert_reqs=CERT_REQUIRED, ca_certs=None):

        if not util.safehasattr(socket, 'ssl'):

            raise util.Abort(_('Python SSL support not found'))

        if ca_certs:

            raise util.Abort(_(

                'certificate checking requires Python 2.6'))

        ssl = socket.ssl(sock, key_file, cert_file)

        return httplib.FakeSocket(sock, ssl)

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.

#

# We COMPLETELY ignore CERT_REQUIRED on Python <= 2.5, as it's totally

# busted on those versions.

def sslkwargs(ui, host):

    cacerts = ui.config('web', 'cacerts')

    hostfingerprint = ui.config('hostfingerprints', host)

    if cacerts and not hostfingerprint:

        cacerts = util.expandpath(cacerts)

        if not os.path.exists(cacerts):

            raise util.Abort(_('could not find web.cacerts: %s') % cacerts)

        return {'ca_certs': cacerts,

                'cert_reqs': CERT_REQUIRED,

                }

    return {}

class validator(object):

    def __init__(self, ui, host):

        self.ui = ui

        self.host = host

    def __call__(self, sock):

        host = self.host

        cacerts = self.ui.config('web', 'cacerts')

        hostfingerprint = self.ui.config('hostfingerprints', host)

        if not getattr(sock, 'getpeercert', False): # python 2.5 ?

            if hostfingerprint:

                raise util.Abort(_("host fingerprint for %s can't be "

                                   "verified (Python too old)") % host)

            if self.ui.configbool('ui', 'reportoldssl', True):

                self.ui.warn(_("warning: certificate for %s can't be verified "

                               "(Python too old)\n") % host)

            return

        if not sock.cipher(): # work around http://bugs.python.org/issue13721

            raise util.Abort(_('%s ssl connection error') % host)

        peercert = sock.getpeercert(True)

        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(sock.getpeercert(), 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)

        else:

            self.ui.warn(_('warning: %s certificate with fingerprint %s not '

                           'verified (check hostfingerprints or web.cacerts '

                           'config setting)\n') %

                         (host, nicefingerprint))