view hgext/acl.py @ 6779:d3147b4e3e8a

hgweb: centralize permission checks for protocol commands

Consistently enforces authorization checks set up in hgrc up front, so that
the actual commands don't have to worry about them and implementers of
hgweb alternatives can easily implement their own permission checks.

# acl.py - changeset access control for mercurial
#
# Copyright 2006 Vadim Gelfer <[e-mail]>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.
#
# this hook allows to allow or deny access to parts of a repo when
# taking incoming changesets.
#
# authorization is against local user name on system where hook is
# run, not committer of original changeset (since that is easy to
# spoof).
#
# acl hook is best to use if you use hgsh to set up restricted shells
# for authenticated users to only push to / pull from.  not safe if
# user has interactive shell access, because they can disable hook.
# also not safe if remote users share one local account, because then
# no way to tell remote users apart.
#
# to use, configure acl extension in hgrc like this:
#
#   [extensions]
#   hgext.acl =
#
#   [hooks]
#   pretxnchangegroup.acl = python:hgext.acl.hook
#
#   [acl]
#   sources = serve        # check if source of incoming changes in this list
#                          # ("serve" == ssh or http, "push", "pull", "bundle")
#
# allow and deny lists have subtree pattern (default syntax is glob)
# on left, user names on right. deny list checked before allow list.
#
#   [acl.allow]
#   # if acl.allow not present, all users allowed by default
#   # empty acl.allow = no users allowed
#   docs/** = doc_writer
#   .hgtags = release_engineer
#
#   [acl.deny]
#   # if acl.deny not present, no users denied by default
#   # empty acl.deny = all users allowed
#   glob pattern = user4, user5
#   ** = user6

from mercurial.i18n import _
from mercurial.node import bin, short
from mercurial import util
import getpass

class checker(object):
    '''acl checker.'''

    def buildmatch(self, key):
        '''return tuple of (match function, list enabled).'''
        if not self.ui.has_section(key):
            self.ui.debug(_('acl: %s not enabled\n') % key)
            return None, False

        thisuser = self.getuser()
        pats = [pat for pat, users in self.ui.configitems(key)
                if thisuser in users.replace(',', ' ').split()]
        self.ui.debug(_('acl: %s enabled, %d entries for user %s\n') %
                      (key, len(pats), thisuser))
        if pats:
            match = util.matcher(self.repo.root, names=pats)[1]
        else:
            match = util.never
        return match, True

    def getuser(self):
        '''return name of authenticated user.'''
        return self.user

    def __init__(self, ui, repo):
        self.ui = ui
        self.repo = repo
        self.user = getpass.getuser()
        cfg = self.ui.config('acl', 'config')
        if cfg:
            self.ui.readsections(cfg, 'acl.allow', 'acl.deny')
        self.allow, self.allowable = self.buildmatch('acl.allow')
        self.deny, self.deniable = self.buildmatch('acl.deny')

    def skipsource(self, source):
        '''true if incoming changes from this source should be skipped.'''
        ok_sources = self.ui.config('acl', 'sources', 'serve').split()
        return source not in ok_sources

    def check(self, node):
        '''return if access allowed, raise exception if not.'''
        files = self.repo[node].files()
        if self.deniable:
            for f in files:
                if self.deny(f):
                    self.ui.debug(_('acl: user %s denied on %s\n') %
                                  (self.getuser(), f))
                    raise util.Abort(_('acl: access denied for changeset %s') %
                                     short(node))
        if self.allowable:
            for f in files:
                if not self.allow(f):
                    self.ui.debug(_('acl: user %s not allowed on %s\n') %
                                  (self.getuser(), f))
                    raise util.Abort(_('acl: access denied for changeset %s') %
                                     short(node))
        self.ui.debug(_('acl: allowing changeset %s\n') % short(node))

def hook(ui, repo, hooktype, node=None, source=None, **kwargs):
    if hooktype != 'pretxnchangegroup':
        raise util.Abort(_('config error - hook type "%s" cannot stop '
                           'incoming changesets') % hooktype)

    c = checker(ui, repo)
    if c.skipsource(source):
        ui.debug(_('acl: changes have source "%s" - skipping\n') % source)
        return

    for rev in xrange(repo[node].rev(), len(repo)):
        c.check(repo.changelog.node(rev))