tests/httpserverauth.py

copies: detect case when a merge decision overwrite previous data

We now detect and record when a merge case required special logic (eg: thing
that append during the merge, ambiguity leading to picking p1 data, etc) and we
explicitly mark the result as superseding the previous data.

This fixes the family of test we previously added.

Differential Revision: https://phab.mercurial-scm.org/D9613

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')