<h2>Editing File: /usr/lib/python3.6/site-packages/setroubleshoot/access_control.py</h2><form method='post'><textarea name='content' class='file-edit'># Authors: Karl MacMillan &lt;kmacmillan@mentalrootkit.com&gt;
#
# Copyright (C) 2006,2007,2008 Red Hat, Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
#

&quot;&quot;&quot;Access control for setroubleshoot. For now this is only used for
determining which users are allowed to connect to the server: see
UserServerAccess for more information.&quot;&quot;&quot;

import struct
import socket as Socket
import syslog

from setroubleshoot.config import get_config
from setroubleshoot.util import syslog_trace

__all__ = [
    'ServerAccess',
]


# SO_PEERCRED is not defined by the socket class unless patched
# SO_PEERCRED's value is architecture dependent
# alpha, mips:    18
# parisc:         0x4011
# powerpc:        21
# sparc, sparc64: 0x0040
# default:        17
try:
    SO_PEERCRED = Socket.SO_PEERCRED
except AttributeError:
    import os
    import re
    machine = os.uname()[4]
    if re.search(r'^i\d86', machine):
        SO_PEERCRED = 17     # i386,i486,i586,i686, etc.
    elif re.search(r'^x86_64', machine):
        SO_PEERCRED = 17     # x86_64
    elif re.search(r'^(ppc|powerpc)', machine):
        SO_PEERCRED = 21     # ppc
    elif re.search(r'^(alpha|mips)', machine):
        SO_PEERCRED = 18     # alpha, mips
    elif re.search(r'^sparc', machine):
        SO_PEERCRED = 0x0040  # sparc
    elif re.search(r'^parisc', machine):
        SO_PEERCRED = 0x4011  # parisc
    else:
        SO_PEERCRED = 17
    #print &quot;hardcoding SO_PEERCRED=%s&quot; % SO_PEERCRED


class ServerAccess:
    &quot;&quot;&quot;
    Determine if a user should be given access to the server based
    on the configuration file.
    &quot;&quot;&quot;

    privileges = {'client': {'wildcard': True},
                  'fix_cmd': {'wildcard': False},
                  }

    def __init__(self):
        # No attempt is made to validate the user name is valid. This
        # makes the configuration file more relaxed. Additionally, the
        # server (which we assume is the only user of this class) will
        # be getting uids from the kernel, so there shouldn't be access
        # requested from invalid uids

        self.privileges = {}
        for privilege in list(ServerAccess.privileges.keys()):
            self.privileges[privilege] = self.init_privilege(privilege)

    def init_privilege(self, privilege):
        cfg_names = [name.strip() for name in
                     get_config('access', '%s_users' % privilege).split(',')]
        return cfg_names

    def valid_privilege(self, privilege):
        valid = privilege in ServerAccess.privileges
        if valid:
            return True
        syslog.syslog(syslog.LOG_ERR, &quot;unknown access privilege (%s)&quot; % privilege)
        return False

    def unrestricted_privilege(self, privilege):
        if not self.valid_privilege(privilege):
            return False

        if not ServerAccess.privileges[privilege]['wildcard']:
            return False
        return '*' in self.privileges[privilege]

    def user_allowed(self, privilege, user):
        &quot;&quot;&quot;
        Determine if the given user name is allowed access.
        Returns True if access should be given, False if not.
        &quot;&quot;&quot;
        if not self.valid_privilege(privilege):
            return False

        if self.unrestricted_privilege(privilege):
            return True
        if user in self.privileges[privilege]:
            return True
        else:
            return False

    def uid_allowed(self, privilege, uid):
        &quot;&quot;&quot;
        Determine if the given uid is allowed access. No error
        is returned if the uid is invalid (False is returned).
        Returns True if access should be given, False if not.
        &quot;&quot;&quot;

        if not self.valid_privilege(privilege):
            return False

        if self.unrestricted_privilege(privilege):
            return True
        try:
            import pwd
            pwd_entry = pwd.getpwuid(uid)
        except KeyError:
            # Not a valid uid - so they don't get access. This
            # is not an error.
            return False

        return self.user_allowed(privilege, pwd_entry[0])

    def get_credentials(self, sock):
        &quot;&quot;&quot;Obtain the effective user and group IDs of the process on
        the other end of a socket. SO_PEERCRED is used so the information
        returned is generally trustworthy (though root processes can
        impersonate any uid/gid).&quot;&quot;&quot;

        pid = uid = gid = None
        try:
            # socket attributes family,type,proto,timeout available only in Python &gt;= 2.5
            family = sock.family
            if family != Socket.AF_UNIX:
                return uid, gid
        except AttributeError:
            # rely on pid,uid,gid being -1 if family is not AF_UNIX
            pass

        format_ucred = 'III'  # pid_t, uid_t, gid_t
        sizeof_ucred = struct.calcsize(format_ucred)

        try:
            ucred = sock.getsockopt(Socket.SOL_SOCKET, SO_PEERCRED, sizeof_ucred)
            pid, uid, gid = struct.unpack(format_ucred, ucred)
            if pid == -1:
                pid = None
            if uid == -1:
                uid = None
            if gid == -1:
                gid = None
        except Exception as e:
            pid = uid = gid = None
            import traceback
            syslog_trace(traceback.format_exc())
            syslog.syslog(syslog.LOG_ERR, &quot;get_credentials(): %s&quot; % e)

        return uid, gid
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