view mercurial/sshserver.py @ 29334:ecc9b788fd69

sslutil: per-host config option to define certificates

Recent work has introduced the [hostsecurity] config section for
defining per-host security settings. This patch builds on top
of this foundation and implements the ability to define a per-host
path to a file containing certificates used for verifying the server
certificate. It is logically a per-host web.cacerts setting.

This patch also introduces a warning when both per-host
certificates and fingerprints are defined. These are mutually
exclusive for host verification and I think the user should be
alerted when security settings are ambiguous because, well,
security is important.

Tests validating the new behavior have been added.

I decided against putting "ca" in the option name because a
non-CA certificate can be specified and used to validate the server
certificate (commonly this will be the exact public certificate
used by the server). It's worth noting that the underlying
Python API used is load_verify_locations(cafile=X) and it calls
into OpenSSL's SSL_CTX_load_verify_locations(). Even OpenSSL's
documentation seems to omit that the file can contain a non-CA
certificate if it matches the server's certificate exactly. I
thought a CA certificate was a special kind of x509 certificate.
Perhaps I'm wrong and any x509 certificate can be used as a
CA certificate [as far as OpenSSL is concerned]. In any case,
I thought it best to drop "ca" from the name because this reflects
reality.

# sshserver.py - ssh protocol server support for mercurial
#
# Copyright 2005-2007 Matt Mackall <[e-mail]>
# Copyright 2006 Vadim Gelfer <[e-mail]>
#
# 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 sys

from . import (
    error,
    hook,
    util,
    wireproto,
)

class sshserver(wireproto.abstractserverproto):
    def __init__(self, ui, repo):
        self.ui = ui
        self.repo = repo
        self.lock = None
        self.fin = ui.fin
        self.fout = ui.fout

        hook.redirect(True)
        ui.fout = repo.ui.fout = ui.ferr

        # Prevent insertion/deletion of CRs
        util.setbinary(self.fin)
        util.setbinary(self.fout)

    def getargs(self, args):
        data = {}
        keys = args.split()
        for n in xrange(len(keys)):
            argline = self.fin.readline()[:-1]
            arg, l = argline.split()
            if arg not in keys:
                raise error.Abort("unexpected parameter %r" % arg)
            if arg == '*':
                star = {}
                for k in xrange(int(l)):
                    argline = self.fin.readline()[:-1]
                    arg, l = argline.split()
                    val = self.fin.read(int(l))
                    star[arg] = val
                data['*'] = star
            else:
                val = self.fin.read(int(l))
                data[arg] = val
        return [data[k] for k in keys]

    def getarg(self, name):
        return self.getargs(name)[0]

    def getfile(self, fpout):
        self.sendresponse('')
        count = int(self.fin.readline())
        while count:
            fpout.write(self.fin.read(count))
            count = int(self.fin.readline())

    def redirect(self):
        pass

    def groupchunks(self, changegroup):
        while True:
            d = changegroup.read(4096)
            if not d:
                break
            yield d

    def sendresponse(self, v):
        self.fout.write("%d\n" % len(v))
        self.fout.write(v)
        self.fout.flush()

    def sendstream(self, source):
        write = self.fout.write
        for chunk in source.gen:
            write(chunk)
        self.fout.flush()

    def sendpushresponse(self, rsp):
        self.sendresponse('')
        self.sendresponse(str(rsp.res))

    def sendpusherror(self, rsp):
        self.sendresponse(rsp.res)

    def sendooberror(self, rsp):
        self.ui.ferr.write('%s\n-\n' % rsp.message)
        self.ui.ferr.flush()
        self.fout.write('\n')
        self.fout.flush()

    def serve_forever(self):
        try:
            while self.serve_one():
                pass
        finally:
            if self.lock is not None:
                self.lock.release()
        sys.exit(0)

    handlers = {
        str: sendresponse,
        wireproto.streamres: sendstream,
        wireproto.pushres: sendpushresponse,
        wireproto.pusherr: sendpusherror,
        wireproto.ooberror: sendooberror,
    }

    def serve_one(self):
        cmd = self.fin.readline()[:-1]
        if cmd and cmd in wireproto.commands:
            rsp = wireproto.dispatch(self.repo, self, cmd)
            self.handlers[rsp.__class__](self, rsp)
        elif cmd:
            impl = getattr(self, 'do_' + cmd, None)
            if impl:
                r = impl()
                if r is not None:
                    self.sendresponse(r)
            else: self.sendresponse("")
        return cmd != ''

    def _client(self):
        client = os.environ.get('SSH_CLIENT', '').split(' ', 1)[0]
        return 'remote:ssh:' + client