text: /*-
   * Copyright (c) 1999, 2000, 2001, 2002 Robert N. M. Watson
   * Copyright (c) 2001, 2002 Networks Associates Technology, Inc.
   * All rights reserved.
   *
   * This software was developed by Robert Watson for the TrustedBSD Project.
   *
   * This software was developed for the FreeBSD Project in part by Network
   * Associates Laboratories, the Security Research Division of Network
   * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
   * as part of the DARPA CHATS research program.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   * $FreeBSD: src/sys/security/mac_seeotheruids/mac_seeotheruids.c,v 1.4 2002/12/10 16:20:34 rwatson Exp $
   */
  
  /*
   * Developed by the TrustedBSD Project.
   * Prevent processes owned by a particular uid from seeing various transient
   * kernel objects associated with other uids.
   */
  
  #include <sys/types.h>
  #include <sys/param.h>
  #include <sys/conf.h>
  #include <sys/kernel.h>
  #include <sys/mac.h>
  #include <sys/mount.h>
  #include <sys/proc.h>
  #include <sys/systm.h>
  #include <sys/sysproto.h>
  #include <sys/sysent.h>
  #include <sys/vnode.h>
  #include <sys/file.h>
  #include <sys/socket.h>
  #include <sys/socketvar.h>
  #include <sys/sysctl.h>
  
  #include <net/bpfdesc.h>
  #include <net/if.h>
  #include <net/if_types.h>
  #include <net/if_var.h>
  
  #include <vm/vm.h>
  
  #include <sys/mac_policy.h>
  
  SYSCTL_DECL(_security_mac);
  
  SYSCTL_NODE(_security_mac, OID_AUTO, seeotheruids, CTLFLAG_RW, 0,
      "TrustedBSD mac_seeotheruids policy controls");
  
  static int	mac_seeotheruids_enabled = 1;
  SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, enabled, CTLFLAG_RW,
      &mac_seeotheruids_enabled, 0, "Enforce seeotheruids policy");
  
  /*
   * Exception: allow credentials to be aware of other credentials with the
   * same primary gid.
   */
  static int	primarygroup_enabled = 0;
  SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, primarygroup_enabled,
      CTLFLAG_RW, &primarygroup_enabled, 0, "Make an exception for credentials "
      "with the same real primary group id");
  
  /*
   * Exception: allow processes with a specific gid to be exempt from the
   * policy.  One sysctl enables this functionality; the other sets the
   * exempt gid.
   */
  static int	specificgid_enabled = 0;
  SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, specificgid_enabled,
      CTLFLAG_RW, &specificgid_enabled, 0, "Make an exception for credentials "
      "with a specific gid as their real primary group id or group set");
  
  static gid_t	specificgid = 0;
  SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, specificgid, CTLFLAG_RW,
      &specificgid, 0, "Specific gid to be exempt from seeotheruids policy");
  
  static int
  mac_seeotheruids_check(struct ucred *u1, struct ucred *u2)
  {
  
  	if (!mac_seeotheruids_enabled)
  		return (0);
  
  	if (primarygroup_enabled) {
  		if (u1->cr_rgid == u2->cr_rgid)
  			return (0);
  	}
  
  	if (specificgid_enabled) {
  		if (u1->cr_rgid == specificgid || groupmember(specificgid, u1))
  			return (0);
  	}
  
  	if (u1->cr_ruid == u2->cr_ruid)
  		return (0);
  
  	return (ESRCH);
  }
  
  static int
  mac_seeotheruids_check_cred_visible(struct ucred *u1, struct ucred *u2)
  {
  
  	return (mac_seeotheruids_check(u1, u2));
  }
  
  static int
  mac_seeotheruids_check_proc_signal(struct ucred *cred, struct proc *proc,
      int signum)
  {
  
  	return (mac_seeotheruids_check(cred, proc->p_ucred));
  }
  
  static int
  mac_seeotheruids_check_proc_sched(struct ucred *cred, struct proc *proc)
  {
  
  	return (mac_seeotheruids_check(cred, proc->p_ucred));
  }
  
  static int
  mac_seeotheruids_check_proc_debug(struct ucred *cred, struct proc *proc)
  {
  
  	return (mac_seeotheruids_check(cred, proc->p_ucred));
  }
  
  static int
  mac_seeotheruids_check_socket_visible(struct ucred *cred, struct socket *socket,
      struct label *socketlabel)
  {
  
  	return (mac_seeotheruids_check(cred, socket->so_cred));
  }
  
  static struct mac_policy_ops mac_seeotheruids_ops =
  {
  	.mpo_check_cred_visible = mac_seeotheruids_check_cred_visible,
  	.mpo_check_proc_debug = mac_seeotheruids_check_proc_debug,
  	.mpo_check_proc_sched = mac_seeotheruids_check_proc_sched,
  	.mpo_check_proc_signal = mac_seeotheruids_check_proc_signal,
  	.mpo_check_socket_visible = mac_seeotheruids_check_socket_visible,
  };
  
  MAC_POLICY_SET(&mac_seeotheruids_ops, trustedbsd_mac_seeotheruids,
      "TrustedBSD MAC/seeotheruids", MPC_LOADTIME_FLAG_UNLOADOK, NULL);
  