view mercurial/hgweb/request.py @ 26120:1a45e49a6bed stable 3.5.1

hgweb: fix trust of templates path (BC)

Long ago we disabled trust of the templates path with a comment
describing the (insecure) behavior before the change. At some later
refactor, the code was apparently changed back to match the comment,
unaware that the intent of the comment was to describe the behavior to
avoid.

This change disables the trust and updates the comment to explicitly
say not only what the old problem was, but also that it was in fact a
problem and the action taken to prevent it.

Impact: prior to this change, if you had a UNIX-based hgweb server
where users can write hgrc files, those users could potentially read
any file readable by the web server.

This is marked as a backwards compatibility issue because people may
have configured templates without proper trust settings. Issue spotted
by Greg Szorc.

# hgweb/request.py - An http request from either CGI or the standalone server.
#
# Copyright 21 May 2005 - (c) 2005 Jake Edge <[e-mail]>
# Copyright 2005, 2006 Matt Mackall <[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.

import socket, cgi, errno
from mercurial import util
from common import ErrorResponse, statusmessage, HTTP_NOT_MODIFIED

shortcuts = {
    'cl': [('cmd', ['changelog']), ('rev', None)],
    'sl': [('cmd', ['shortlog']), ('rev', None)],
    'cs': [('cmd', ['changeset']), ('node', None)],
    'f': [('cmd', ['file']), ('filenode', None)],
    'fl': [('cmd', ['filelog']), ('filenode', None)],
    'fd': [('cmd', ['filediff']), ('node', None)],
    'fa': [('cmd', ['annotate']), ('filenode', None)],
    'mf': [('cmd', ['manifest']), ('manifest', None)],
    'ca': [('cmd', ['archive']), ('node', None)],
    'tags': [('cmd', ['tags'])],
    'tip': [('cmd', ['changeset']), ('node', ['tip'])],
    'static': [('cmd', ['static']), ('file', None)]
}

def normalize(form):
    # first expand the shortcuts
    for k in shortcuts.iterkeys():
        if k in form:
            for name, value in shortcuts[k]:
                if value is None:
                    value = form[k]
                form[name] = value
            del form[k]
    # And strip the values
    for k, v in form.iteritems():
        form[k] = [i.strip() for i in v]
    return form

class wsgirequest(object):
    def __init__(self, wsgienv, start_response):
        version = wsgienv['wsgi.version']
        if (version < (1, 0)) or (version >= (2, 0)):
            raise RuntimeError("Unknown and unsupported WSGI version %d.%d"
                               % version)
        self.inp = wsgienv['wsgi.input']
        self.err = wsgienv['wsgi.errors']
        self.threaded = wsgienv['wsgi.multithread']
        self.multiprocess = wsgienv['wsgi.multiprocess']
        self.run_once = wsgienv['wsgi.run_once']
        self.env = wsgienv
        self.form = normalize(cgi.parse(self.inp,
                                        self.env,
                                        keep_blank_values=1))
        self._start_response = start_response
        self.server_write = None
        self.headers = []

    def __iter__(self):
        return iter([])

    def read(self, count=-1):
        return self.inp.read(count)

    def drain(self):
        '''need to read all data from request, httplib is half-duplex'''
        length = int(self.env.get('CONTENT_LENGTH') or 0)
        for s in util.filechunkiter(self.inp, limit=length):
            pass

    def respond(self, status, type, filename=None, body=None):
        if self._start_response is not None:
            self.headers.append(('Content-Type', type))
            if filename:
                filename = (filename.split('/')[-1]
                            .replace('\\', '\\\\').replace('"', '\\"'))
                self.headers.append(('Content-Disposition',
                                     'inline; filename="%s"' % filename))
            if body is not None:
                self.headers.append(('Content-Length', str(len(body))))

            for k, v in self.headers:
                if not isinstance(v, str):
                    raise TypeError('header value must be string: %r' % (v,))

            if isinstance(status, ErrorResponse):
                self.headers.extend(status.headers)
                if status.code == HTTP_NOT_MODIFIED:
                    # RFC 2616 Section 10.3.5: 304 Not Modified has cases where
                    # it MUST NOT include any headers other than these and no
                    # body
                    self.headers = [(k, v) for (k, v) in self.headers if
                                    k in ('Date', 'ETag', 'Expires',
                                          'Cache-Control', 'Vary')]
                status = statusmessage(status.code, status.message)
            elif status == 200:
                status = '200 Script output follows'
            elif isinstance(status, int):
                status = statusmessage(status)

            self.server_write = self._start_response(status, self.headers)
            self._start_response = None
            self.headers = []
        if body is not None:
            self.write(body)
            self.server_write = None

    def write(self, thing):
        if thing:
            try:
                self.server_write(thing)
            except socket.error as inst:
                if inst[0] != errno.ECONNRESET:
                    raise

    def writelines(self, lines):
        for line in lines:
            self.write(line)

    def flush(self):
        return None

    def close(self):
        return None

def wsgiapplication(app_maker):
    '''For compatibility with old CGI scripts. A plain hgweb() or hgwebdir()
    can and should now be used as a WSGI application.'''
    application = app_maker()
    def run_wsgi(env, respond):
        return application(env, respond)
    return run_wsgi