# 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

    ssl_wrap_socket = ssl.wrap_socket

    CERT_REQUIRED = ssl.CERT_REQUIRED

except ImportError:

    CERT_REQUIRED = 2

    def ssl_wrap_socket(sock, key_file, cert_file,

                        cert_reqs=CERT_REQUIRED, ca_certs=None):

        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

        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 cacerts and not hostfingerprint:

            msg = _verifycert(sock.getpeercert(), host)

            if msg:

                raise util.Abort(_('%s certificate error: %s '

                                   '(use --insecure to connect '

                                   'insecurely)') % (host, msg))

            self.ui.debug('%s certificate successfully verified\n' % host)

        else:

            if getattr(sock, 'getpeercert', False):

                peercert = sock.getpeercert(True)

                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(_('invalid certificate for %s '

                                           'with fingerprint %s') %

                                         (host, nicefingerprint))

                    self.ui.debug('%s certificate matched fingerprint %s\n' %

                                  (host, nicefingerprint))

                else:

                    self.ui.warn(_('warning: %s certificate '

                                   'with fingerprint %s not verified '

                                   '(check hostfingerprints or web.cacerts '

                                   'config setting)\n') %

                                 (host, nicefingerprint))

            else: # python 2.5 ?

                if hostfingerprint:

                    raise util.Abort(_('no certificate for %s with '

                                       'configured hostfingerprint') % host)

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

                               '(check web.cacerts config setting)\n') %

                             host)