tests/httpserverauth.py

sharesafe: introduce functionality to automatically upgrade shares

In past few months, we have developed a `share-safe` mode for sharing repository
in which share source requirements and config values are shared with the shares.

To get it rolling, an important task is to get these shares automatically
upgraded. We are focusing on an installation where shares are created by scripts
and test jobs. It will be difficult to manually upgrade these and we need some
functionality to do so automatically.

This patch introduces a config option to deal with it. If all of the following
conditions are met, we upgrade the share repository automatically:

* If the config option is enabled
* Share source repository is share-safe enabled
* Share is not share-safe enabled
* Any command is run in the share

Upgrading the share is pretty easy as it involves only editing the requirements
file.

Differential Revision: https://phab.mercurial-scm.org/D9679

from __future__ import absolute_import

import base64
import hashlib

from mercurial.hgweb import common
from mercurial import node


def parse_keqv_list(req, l):
    """Parse list of key=value strings where keys are not duplicated."""
    parsed = {}
    for elt in l:
        k, v = elt.split(b'=', 1)
        if v[0:1] == b'"' and v[-1:] == b'"':
            v = v[1:-1]
        parsed[k] = v
    return parsed


class digestauthserver(object):
    def __init__(self):
        self._user_hashes = {}

    def gethashers(self):
        def _md5sum(x):
            m = hashlib.md5()
            m.update(x)
            return node.hex(m.digest())

        h = _md5sum

        kd = lambda s, d, h=h: h(b"%s:%s" % (s, d))
        return h, kd

    def adduser(self, user, password, realm):
        h, kd = self.gethashers()
        a1 = h(b'%s:%s:%s' % (user, realm, password))
        self._user_hashes[(user, realm)] = a1

    def makechallenge(self, realm):
        # We aren't testing the protocol here, just that the bytes make the
        # proper round trip.  So hardcoded seems fine.
        nonce = b'064af982c5b571cea6450d8eda91c20d'
        return b'realm="%s", nonce="%s", algorithm=MD5, qop="auth"' % (
            realm,
            nonce,
        )

    def checkauth(self, req, header):
        log = req.rawenv[b'wsgi.errors']

        h, kd = self.gethashers()
        resp = parse_keqv_list(req, header.split(b', '))

        if resp.get(b'algorithm', b'MD5').upper() != b'MD5':
            log.write(b'Unsupported algorithm: %s' % resp.get(b'algorithm'))
            raise common.ErrorResponse(
                common.HTTP_FORBIDDEN, b"unknown algorithm"
            )
        user = resp[b'username']
        realm = resp[b'realm']
        nonce = resp[b'nonce']

        ha1 = self._user_hashes.get((user, realm))
        if not ha1:
            log.write(b'No hash found for user/realm "%s/%s"' % (user, realm))
            raise common.ErrorResponse(common.HTTP_FORBIDDEN, b"bad user")

        qop = resp.get(b'qop', b'auth')
        if qop != b'auth':
            log.write(b"Unsupported qop: %s" % qop)
            raise common.ErrorResponse(common.HTTP_FORBIDDEN, b"bad qop")

        cnonce, ncvalue = resp.get(b'cnonce'), resp.get(b'nc')
        if not cnonce or not ncvalue:
            log.write(b'No cnonce (%s) or ncvalue (%s)' % (cnonce, ncvalue))
            raise common.ErrorResponse(common.HTTP_FORBIDDEN, b"no cnonce")

        a2 = b'%s:%s' % (req.method, resp[b'uri'])
        noncebit = b"%s:%s:%s:%s:%s" % (nonce, ncvalue, cnonce, qop, h(a2))

        respdig = kd(ha1, noncebit)
        if respdig != resp[b'response']:
            log.write(
                b'User/realm "%s/%s" gave %s, but expected %s'
                % (user, realm, resp[b'response'], respdig)
            )
            return False

        return True


digest = digestauthserver()


def perform_authentication(hgweb, req, op):
    auth = req.headers.get(b'Authorization')

    if req.headers.get(b'X-HgTest-AuthType') == b'Digest':
        if not auth:
            challenge = digest.makechallenge(b'mercurial')
            raise common.ErrorResponse(
                common.HTTP_UNAUTHORIZED,
                b'who',
                [(b'WWW-Authenticate', b'Digest %s' % challenge)],
            )

        if not digest.checkauth(req, auth[7:]):
            raise common.ErrorResponse(common.HTTP_FORBIDDEN, b'no')

        return

    if not auth:
        raise common.ErrorResponse(
            common.HTTP_UNAUTHORIZED,
            b'who',
            [(b'WWW-Authenticate', b'Basic Realm="mercurial"')],
        )

    if base64.b64decode(auth.split()[1]).split(b':', 1) != [b'user', b'pass']:
        raise common.ErrorResponse(common.HTTP_FORBIDDEN, b'no')


def extsetup(ui):
    common.permhooks.insert(0, perform_authentication)
    digest.adduser(b'user', b'pass', b'mercurial')