mirror of
https://git.FreeBSD.org/src.git
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df04411ac4
thread-local pointer, in practice that thread needs to be curthread. If we're running with INVARIANTS, generate a warning if not. If we have KDB compiled in, generate a stack trace. This doesn't fire at all in my local test environment, but could be irritating if it fires frequently for someone, so there will be motivation to fix things quickly when it does.
2044 lines
46 KiB
C
2044 lines
46 KiB
C
/*
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* Copyright (c) 1982, 1986, 1989, 1990, 1991, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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* Copyright (c) 2000-2001 Robert N. M. Watson. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)kern_prot.c 8.6 (Berkeley) 1/21/94
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*/
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/*
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* System calls related to processes and protection
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_compat.h"
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#include "opt_mac.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/acct.h>
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#include <sys/kdb.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/mac.h>
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#include <sys/malloc.h>
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#include <sys/mutex.h>
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#include <sys/sx.h>
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#include <sys/proc.h>
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#include <sys/sysproto.h>
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#include <sys/jail.h>
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#include <sys/pioctl.h>
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#include <sys/resourcevar.h>
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#include <sys/socket.h>
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#include <sys/socketvar.h>
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#include <sys/sysctl.h>
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static MALLOC_DEFINE(M_CRED, "cred", "credentials");
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SYSCTL_DECL(_security);
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SYSCTL_NODE(_security, OID_AUTO, bsd, CTLFLAG_RW, 0,
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"BSD security policy");
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#ifndef _SYS_SYSPROTO_H_
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struct getpid_args {
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int dummy;
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};
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#endif
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/*
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* MPSAFE
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*/
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/* ARGSUSED */
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int
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getpid(struct thread *td, struct getpid_args *uap)
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{
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struct proc *p = td->td_proc;
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td->td_retval[0] = p->p_pid;
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#if defined(COMPAT_43)
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PROC_LOCK(p);
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td->td_retval[1] = p->p_pptr->p_pid;
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PROC_UNLOCK(p);
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#endif
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return (0);
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}
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#ifndef _SYS_SYSPROTO_H_
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struct getppid_args {
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int dummy;
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};
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#endif
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/*
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* MPSAFE
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*/
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/* ARGSUSED */
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int
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getppid(struct thread *td, struct getppid_args *uap)
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{
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struct proc *p = td->td_proc;
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PROC_LOCK(p);
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td->td_retval[0] = p->p_pptr->p_pid;
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PROC_UNLOCK(p);
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return (0);
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}
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/*
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* Get process group ID; note that POSIX getpgrp takes no parameter.
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*/
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#ifndef _SYS_SYSPROTO_H_
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struct getpgrp_args {
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int dummy;
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};
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#endif
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/*
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* MPSAFE
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*/
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int
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getpgrp(struct thread *td, struct getpgrp_args *uap)
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{
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struct proc *p = td->td_proc;
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PROC_LOCK(p);
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td->td_retval[0] = p->p_pgrp->pg_id;
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PROC_UNLOCK(p);
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return (0);
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}
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/* Get an arbitary pid's process group id */
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#ifndef _SYS_SYSPROTO_H_
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struct getpgid_args {
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pid_t pid;
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};
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#endif
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/*
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* MPSAFE
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*/
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int
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getpgid(struct thread *td, struct getpgid_args *uap)
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{
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struct proc *p;
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int error;
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if (uap->pid == 0) {
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p = td->td_proc;
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PROC_LOCK(p);
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} else {
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p = pfind(uap->pid);
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if (p == NULL)
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return (ESRCH);
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error = p_cansee(td, p);
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if (error) {
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PROC_UNLOCK(p);
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return (error);
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}
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}
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td->td_retval[0] = p->p_pgrp->pg_id;
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PROC_UNLOCK(p);
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return (0);
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}
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/*
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* Get an arbitary pid's session id.
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*/
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#ifndef _SYS_SYSPROTO_H_
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struct getsid_args {
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pid_t pid;
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};
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#endif
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/*
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* MPSAFE
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*/
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int
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getsid(struct thread *td, struct getsid_args *uap)
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{
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struct proc *p;
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int error;
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if (uap->pid == 0) {
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p = td->td_proc;
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PROC_LOCK(p);
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} else {
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p = pfind(uap->pid);
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if (p == NULL)
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return (ESRCH);
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error = p_cansee(td, p);
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if (error) {
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PROC_UNLOCK(p);
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return (error);
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}
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}
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td->td_retval[0] = p->p_session->s_sid;
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PROC_UNLOCK(p);
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return (0);
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}
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#ifndef _SYS_SYSPROTO_H_
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struct getuid_args {
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int dummy;
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};
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#endif
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/*
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* MPSAFE
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*/
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/* ARGSUSED */
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int
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getuid(struct thread *td, struct getuid_args *uap)
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{
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td->td_retval[0] = td->td_ucred->cr_ruid;
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#if defined(COMPAT_43)
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td->td_retval[1] = td->td_ucred->cr_uid;
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#endif
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return (0);
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}
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#ifndef _SYS_SYSPROTO_H_
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struct geteuid_args {
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int dummy;
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};
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#endif
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/*
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* MPSAFE
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*/
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/* ARGSUSED */
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int
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geteuid(struct thread *td, struct geteuid_args *uap)
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{
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td->td_retval[0] = td->td_ucred->cr_uid;
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return (0);
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}
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#ifndef _SYS_SYSPROTO_H_
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struct getgid_args {
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int dummy;
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};
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#endif
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/*
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* MPSAFE
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*/
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/* ARGSUSED */
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int
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getgid(struct thread *td, struct getgid_args *uap)
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{
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td->td_retval[0] = td->td_ucred->cr_rgid;
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#if defined(COMPAT_43)
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td->td_retval[1] = td->td_ucred->cr_groups[0];
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#endif
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return (0);
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}
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/*
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* Get effective group ID. The "egid" is groups[0], and could be obtained
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* via getgroups. This syscall exists because it is somewhat painful to do
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* correctly in a library function.
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*/
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#ifndef _SYS_SYSPROTO_H_
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struct getegid_args {
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int dummy;
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};
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#endif
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/*
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* MPSAFE
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*/
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/* ARGSUSED */
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int
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getegid(struct thread *td, struct getegid_args *uap)
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{
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td->td_retval[0] = td->td_ucred->cr_groups[0];
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return (0);
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}
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#ifndef _SYS_SYSPROTO_H_
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struct getgroups_args {
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u_int gidsetsize;
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gid_t *gidset;
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};
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#endif
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/*
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* MPSAFE
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*/
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int
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getgroups(struct thread *td, register struct getgroups_args *uap)
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{
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struct ucred *cred;
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u_int ngrp;
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int error;
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cred = td->td_ucred;
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if ((ngrp = uap->gidsetsize) == 0) {
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td->td_retval[0] = cred->cr_ngroups;
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return (0);
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}
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if (ngrp < cred->cr_ngroups)
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return (EINVAL);
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ngrp = cred->cr_ngroups;
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error = copyout(cred->cr_groups, uap->gidset, ngrp * sizeof(gid_t));
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if (error == 0)
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td->td_retval[0] = ngrp;
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return (error);
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}
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#ifndef _SYS_SYSPROTO_H_
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struct setsid_args {
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int dummy;
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};
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#endif
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/*
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* MPSAFE
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*/
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/* ARGSUSED */
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int
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setsid(register struct thread *td, struct setsid_args *uap)
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{
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struct pgrp *pgrp;
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int error;
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struct proc *p = td->td_proc;
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struct pgrp *newpgrp;
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struct session *newsess;
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error = 0;
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pgrp = NULL;
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MALLOC(newpgrp, struct pgrp *, sizeof(struct pgrp), M_PGRP, M_WAITOK | M_ZERO);
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MALLOC(newsess, struct session *, sizeof(struct session), M_SESSION, M_WAITOK | M_ZERO);
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sx_xlock(&proctree_lock);
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if (p->p_pgid == p->p_pid || (pgrp = pgfind(p->p_pid)) != NULL) {
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if (pgrp != NULL)
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PGRP_UNLOCK(pgrp);
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error = EPERM;
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} else {
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(void)enterpgrp(p, p->p_pid, newpgrp, newsess);
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td->td_retval[0] = p->p_pid;
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newpgrp = NULL;
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newsess = NULL;
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}
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sx_xunlock(&proctree_lock);
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if (newpgrp != NULL)
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FREE(newpgrp, M_PGRP);
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if (newsess != NULL)
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FREE(newsess, M_SESSION);
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return (error);
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}
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/*
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* set process group (setpgid/old setpgrp)
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*
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* caller does setpgid(targpid, targpgid)
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*
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* pid must be caller or child of caller (ESRCH)
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* if a child
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* pid must be in same session (EPERM)
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* pid can't have done an exec (EACCES)
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* if pgid != pid
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* there must exist some pid in same session having pgid (EPERM)
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* pid must not be session leader (EPERM)
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*/
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#ifndef _SYS_SYSPROTO_H_
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struct setpgid_args {
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int pid; /* target process id */
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int pgid; /* target pgrp id */
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};
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#endif
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/*
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* MPSAFE
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*/
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/* ARGSUSED */
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int
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setpgid(struct thread *td, register struct setpgid_args *uap)
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{
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struct proc *curp = td->td_proc;
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register struct proc *targp; /* target process */
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register struct pgrp *pgrp; /* target pgrp */
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int error;
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struct pgrp *newpgrp;
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if (uap->pgid < 0)
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return (EINVAL);
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error = 0;
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MALLOC(newpgrp, struct pgrp *, sizeof(struct pgrp), M_PGRP, M_WAITOK | M_ZERO);
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sx_xlock(&proctree_lock);
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if (uap->pid != 0 && uap->pid != curp->p_pid) {
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if ((targp = pfind(uap->pid)) == NULL) {
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error = ESRCH;
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goto done;
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}
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if (!inferior(targp)) {
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PROC_UNLOCK(targp);
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error = ESRCH;
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goto done;
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}
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if ((error = p_cansee(curthread, targp))) {
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PROC_UNLOCK(targp);
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goto done;
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}
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if (targp->p_pgrp == NULL ||
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targp->p_session != curp->p_session) {
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PROC_UNLOCK(targp);
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error = EPERM;
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goto done;
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}
|
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if (targp->p_flag & P_EXEC) {
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PROC_UNLOCK(targp);
|
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error = EACCES;
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goto done;
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}
|
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PROC_UNLOCK(targp);
|
|
} else
|
|
targp = curp;
|
|
if (SESS_LEADER(targp)) {
|
|
error = EPERM;
|
|
goto done;
|
|
}
|
|
if (uap->pgid == 0)
|
|
uap->pgid = targp->p_pid;
|
|
if ((pgrp = pgfind(uap->pgid)) == NULL) {
|
|
if (uap->pgid == targp->p_pid) {
|
|
error = enterpgrp(targp, uap->pgid, newpgrp,
|
|
NULL);
|
|
if (error == 0)
|
|
newpgrp = NULL;
|
|
} else
|
|
error = EPERM;
|
|
} else {
|
|
if (pgrp == targp->p_pgrp) {
|
|
PGRP_UNLOCK(pgrp);
|
|
goto done;
|
|
}
|
|
if (pgrp->pg_id != targp->p_pid &&
|
|
pgrp->pg_session != curp->p_session) {
|
|
PGRP_UNLOCK(pgrp);
|
|
error = EPERM;
|
|
goto done;
|
|
}
|
|
PGRP_UNLOCK(pgrp);
|
|
error = enterthispgrp(targp, pgrp);
|
|
}
|
|
done:
|
|
sx_xunlock(&proctree_lock);
|
|
KASSERT((error == 0) || (newpgrp != NULL),
|
|
("setpgid failed and newpgrp is NULL"));
|
|
if (newpgrp != NULL)
|
|
FREE(newpgrp, M_PGRP);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Use the clause in B.4.2.2 that allows setuid/setgid to be 4.2/4.3BSD
|
|
* compatible. It says that setting the uid/gid to euid/egid is a special
|
|
* case of "appropriate privilege". Once the rules are expanded out, this
|
|
* basically means that setuid(nnn) sets all three id's, in all permitted
|
|
* cases unless _POSIX_SAVED_IDS is enabled. In that case, setuid(getuid())
|
|
* does not set the saved id - this is dangerous for traditional BSD
|
|
* programs. For this reason, we *really* do not want to set
|
|
* _POSIX_SAVED_IDS and do not want to clear POSIX_APPENDIX_B_4_2_2.
|
|
*/
|
|
#define POSIX_APPENDIX_B_4_2_2
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setuid_args {
|
|
uid_t uid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setuid(struct thread *td, struct setuid_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
uid_t uid;
|
|
struct uidinfo *uip;
|
|
int error;
|
|
|
|
uid = uap->uid;
|
|
newcred = crget();
|
|
uip = uifind(uid);
|
|
PROC_LOCK(p);
|
|
oldcred = p->p_ucred;
|
|
|
|
/*
|
|
* See if we have "permission" by POSIX 1003.1 rules.
|
|
*
|
|
* Note that setuid(geteuid()) is a special case of
|
|
* "appropriate privileges" in appendix B.4.2.2. We need
|
|
* to use this clause to be compatible with traditional BSD
|
|
* semantics. Basically, it means that "setuid(xx)" sets all
|
|
* three id's (assuming you have privs).
|
|
*
|
|
* Notes on the logic. We do things in three steps.
|
|
* 1: We determine if the euid is going to change, and do EPERM
|
|
* right away. We unconditionally change the euid later if this
|
|
* test is satisfied, simplifying that part of the logic.
|
|
* 2: We determine if the real and/or saved uids are going to
|
|
* change. Determined by compile options.
|
|
* 3: Change euid last. (after tests in #2 for "appropriate privs")
|
|
*/
|
|
if (uid != oldcred->cr_ruid && /* allow setuid(getuid()) */
|
|
#ifdef _POSIX_SAVED_IDS
|
|
uid != oldcred->cr_svuid && /* allow setuid(saved gid) */
|
|
#endif
|
|
#ifdef POSIX_APPENDIX_B_4_2_2 /* Use BSD-compat clause from B.4.2.2 */
|
|
uid != oldcred->cr_uid && /* allow setuid(geteuid()) */
|
|
#endif
|
|
(error = suser_cred(oldcred, PRISON_ROOT)) != 0) {
|
|
PROC_UNLOCK(p);
|
|
uifree(uip);
|
|
crfree(newcred);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Copy credentials so other references do not see our changes.
|
|
*/
|
|
crcopy(newcred, oldcred);
|
|
#ifdef _POSIX_SAVED_IDS
|
|
/*
|
|
* Do we have "appropriate privileges" (are we root or uid == euid)
|
|
* If so, we are changing the real uid and/or saved uid.
|
|
*/
|
|
if (
|
|
#ifdef POSIX_APPENDIX_B_4_2_2 /* Use the clause from B.4.2.2 */
|
|
uid == oldcred->cr_uid ||
|
|
#endif
|
|
suser_cred(oldcred, PRISON_ROOT) == 0) /* we are using privs */
|
|
#endif
|
|
{
|
|
/*
|
|
* Set the real uid and transfer proc count to new user.
|
|
*/
|
|
if (uid != oldcred->cr_ruid) {
|
|
change_ruid(newcred, uip);
|
|
setsugid(p);
|
|
}
|
|
/*
|
|
* Set saved uid
|
|
*
|
|
* XXX always set saved uid even if not _POSIX_SAVED_IDS, as
|
|
* the security of seteuid() depends on it. B.4.2.2 says it
|
|
* is important that we should do this.
|
|
*/
|
|
if (uid != oldcred->cr_svuid) {
|
|
change_svuid(newcred, uid);
|
|
setsugid(p);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* In all permitted cases, we are changing the euid.
|
|
*/
|
|
if (uid != oldcred->cr_uid) {
|
|
change_euid(newcred, uip);
|
|
setsugid(p);
|
|
}
|
|
p->p_ucred = newcred;
|
|
PROC_UNLOCK(p);
|
|
uifree(uip);
|
|
crfree(oldcred);
|
|
return (0);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct seteuid_args {
|
|
uid_t euid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
seteuid(struct thread *td, struct seteuid_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
uid_t euid;
|
|
struct uidinfo *euip;
|
|
int error;
|
|
|
|
euid = uap->euid;
|
|
newcred = crget();
|
|
euip = uifind(euid);
|
|
PROC_LOCK(p);
|
|
oldcred = p->p_ucred;
|
|
if (euid != oldcred->cr_ruid && /* allow seteuid(getuid()) */
|
|
euid != oldcred->cr_svuid && /* allow seteuid(saved uid) */
|
|
(error = suser_cred(oldcred, PRISON_ROOT)) != 0) {
|
|
PROC_UNLOCK(p);
|
|
uifree(euip);
|
|
crfree(newcred);
|
|
return (error);
|
|
}
|
|
/*
|
|
* Everything's okay, do it. Copy credentials so other references do
|
|
* not see our changes.
|
|
*/
|
|
crcopy(newcred, oldcred);
|
|
if (oldcred->cr_uid != euid) {
|
|
change_euid(newcred, euip);
|
|
setsugid(p);
|
|
}
|
|
p->p_ucred = newcred;
|
|
PROC_UNLOCK(p);
|
|
uifree(euip);
|
|
crfree(oldcred);
|
|
return (0);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setgid_args {
|
|
gid_t gid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setgid(struct thread *td, struct setgid_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
gid_t gid;
|
|
int error;
|
|
|
|
gid = uap->gid;
|
|
newcred = crget();
|
|
PROC_LOCK(p);
|
|
oldcred = p->p_ucred;
|
|
|
|
/*
|
|
* See if we have "permission" by POSIX 1003.1 rules.
|
|
*
|
|
* Note that setgid(getegid()) is a special case of
|
|
* "appropriate privileges" in appendix B.4.2.2. We need
|
|
* to use this clause to be compatible with traditional BSD
|
|
* semantics. Basically, it means that "setgid(xx)" sets all
|
|
* three id's (assuming you have privs).
|
|
*
|
|
* For notes on the logic here, see setuid() above.
|
|
*/
|
|
if (gid != oldcred->cr_rgid && /* allow setgid(getgid()) */
|
|
#ifdef _POSIX_SAVED_IDS
|
|
gid != oldcred->cr_svgid && /* allow setgid(saved gid) */
|
|
#endif
|
|
#ifdef POSIX_APPENDIX_B_4_2_2 /* Use BSD-compat clause from B.4.2.2 */
|
|
gid != oldcred->cr_groups[0] && /* allow setgid(getegid()) */
|
|
#endif
|
|
(error = suser_cred(oldcred, PRISON_ROOT)) != 0) {
|
|
PROC_UNLOCK(p);
|
|
crfree(newcred);
|
|
return (error);
|
|
}
|
|
|
|
crcopy(newcred, oldcred);
|
|
#ifdef _POSIX_SAVED_IDS
|
|
/*
|
|
* Do we have "appropriate privileges" (are we root or gid == egid)
|
|
* If so, we are changing the real uid and saved gid.
|
|
*/
|
|
if (
|
|
#ifdef POSIX_APPENDIX_B_4_2_2 /* use the clause from B.4.2.2 */
|
|
gid == oldcred->cr_groups[0] ||
|
|
#endif
|
|
suser_cred(oldcred, PRISON_ROOT) == 0) /* we are using privs */
|
|
#endif
|
|
{
|
|
/*
|
|
* Set real gid
|
|
*/
|
|
if (oldcred->cr_rgid != gid) {
|
|
change_rgid(newcred, gid);
|
|
setsugid(p);
|
|
}
|
|
/*
|
|
* Set saved gid
|
|
*
|
|
* XXX always set saved gid even if not _POSIX_SAVED_IDS, as
|
|
* the security of setegid() depends on it. B.4.2.2 says it
|
|
* is important that we should do this.
|
|
*/
|
|
if (oldcred->cr_svgid != gid) {
|
|
change_svgid(newcred, gid);
|
|
setsugid(p);
|
|
}
|
|
}
|
|
/*
|
|
* In all cases permitted cases, we are changing the egid.
|
|
* Copy credentials so other references do not see our changes.
|
|
*/
|
|
if (oldcred->cr_groups[0] != gid) {
|
|
change_egid(newcred, gid);
|
|
setsugid(p);
|
|
}
|
|
p->p_ucred = newcred;
|
|
PROC_UNLOCK(p);
|
|
crfree(oldcred);
|
|
return (0);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setegid_args {
|
|
gid_t egid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setegid(struct thread *td, struct setegid_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
gid_t egid;
|
|
int error;
|
|
|
|
egid = uap->egid;
|
|
newcred = crget();
|
|
PROC_LOCK(p);
|
|
oldcred = p->p_ucred;
|
|
if (egid != oldcred->cr_rgid && /* allow setegid(getgid()) */
|
|
egid != oldcred->cr_svgid && /* allow setegid(saved gid) */
|
|
(error = suser_cred(oldcred, PRISON_ROOT)) != 0) {
|
|
PROC_UNLOCK(p);
|
|
crfree(newcred);
|
|
return (error);
|
|
}
|
|
crcopy(newcred, oldcred);
|
|
if (oldcred->cr_groups[0] != egid) {
|
|
change_egid(newcred, egid);
|
|
setsugid(p);
|
|
}
|
|
p->p_ucred = newcred;
|
|
PROC_UNLOCK(p);
|
|
crfree(oldcred);
|
|
return (0);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setgroups_args {
|
|
u_int gidsetsize;
|
|
gid_t *gidset;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setgroups(struct thread *td, struct setgroups_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *tempcred, *oldcred;
|
|
u_int ngrp;
|
|
int error;
|
|
|
|
ngrp = uap->gidsetsize;
|
|
if (ngrp > NGROUPS)
|
|
return (EINVAL);
|
|
tempcred = crget();
|
|
error = copyin(uap->gidset, tempcred->cr_groups, ngrp * sizeof(gid_t));
|
|
if (error != 0) {
|
|
crfree(tempcred);
|
|
return (error);
|
|
}
|
|
newcred = crget();
|
|
PROC_LOCK(p);
|
|
oldcred = p->p_ucred;
|
|
error = suser_cred(oldcred, PRISON_ROOT);
|
|
if (error) {
|
|
PROC_UNLOCK(p);
|
|
crfree(newcred);
|
|
crfree(tempcred);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* XXX A little bit lazy here. We could test if anything has
|
|
* changed before crcopy() and setting P_SUGID.
|
|
*/
|
|
crcopy(newcred, oldcred);
|
|
if (ngrp < 1) {
|
|
/*
|
|
* setgroups(0, NULL) is a legitimate way of clearing the
|
|
* groups vector on non-BSD systems (which generally do not
|
|
* have the egid in the groups[0]). We risk security holes
|
|
* when running non-BSD software if we do not do the same.
|
|
*/
|
|
newcred->cr_ngroups = 1;
|
|
} else {
|
|
bcopy(tempcred->cr_groups, newcred->cr_groups,
|
|
ngrp * sizeof(gid_t));
|
|
newcred->cr_ngroups = ngrp;
|
|
}
|
|
setsugid(p);
|
|
p->p_ucred = newcred;
|
|
PROC_UNLOCK(p);
|
|
crfree(tempcred);
|
|
crfree(oldcred);
|
|
return (0);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setreuid_args {
|
|
uid_t ruid;
|
|
uid_t euid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setreuid(register struct thread *td, struct setreuid_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
uid_t euid, ruid;
|
|
struct uidinfo *euip, *ruip;
|
|
int error;
|
|
|
|
euid = uap->euid;
|
|
ruid = uap->ruid;
|
|
newcred = crget();
|
|
euip = uifind(euid);
|
|
ruip = uifind(ruid);
|
|
PROC_LOCK(p);
|
|
oldcred = p->p_ucred;
|
|
if (((ruid != (uid_t)-1 && ruid != oldcred->cr_ruid &&
|
|
ruid != oldcred->cr_svuid) ||
|
|
(euid != (uid_t)-1 && euid != oldcred->cr_uid &&
|
|
euid != oldcred->cr_ruid && euid != oldcred->cr_svuid)) &&
|
|
(error = suser_cred(oldcred, PRISON_ROOT)) != 0) {
|
|
PROC_UNLOCK(p);
|
|
uifree(ruip);
|
|
uifree(euip);
|
|
crfree(newcred);
|
|
return (error);
|
|
}
|
|
crcopy(newcred, oldcred);
|
|
if (euid != (uid_t)-1 && oldcred->cr_uid != euid) {
|
|
change_euid(newcred, euip);
|
|
setsugid(p);
|
|
}
|
|
if (ruid != (uid_t)-1 && oldcred->cr_ruid != ruid) {
|
|
change_ruid(newcred, ruip);
|
|
setsugid(p);
|
|
}
|
|
if ((ruid != (uid_t)-1 || newcred->cr_uid != newcred->cr_ruid) &&
|
|
newcred->cr_svuid != newcred->cr_uid) {
|
|
change_svuid(newcred, newcred->cr_uid);
|
|
setsugid(p);
|
|
}
|
|
p->p_ucred = newcred;
|
|
PROC_UNLOCK(p);
|
|
uifree(ruip);
|
|
uifree(euip);
|
|
crfree(oldcred);
|
|
return (0);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setregid_args {
|
|
gid_t rgid;
|
|
gid_t egid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setregid(register struct thread *td, struct setregid_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
gid_t egid, rgid;
|
|
int error;
|
|
|
|
egid = uap->egid;
|
|
rgid = uap->rgid;
|
|
newcred = crget();
|
|
PROC_LOCK(p);
|
|
oldcred = p->p_ucred;
|
|
if (((rgid != (gid_t)-1 && rgid != oldcred->cr_rgid &&
|
|
rgid != oldcred->cr_svgid) ||
|
|
(egid != (gid_t)-1 && egid != oldcred->cr_groups[0] &&
|
|
egid != oldcred->cr_rgid && egid != oldcred->cr_svgid)) &&
|
|
(error = suser_cred(oldcred, PRISON_ROOT)) != 0) {
|
|
PROC_UNLOCK(p);
|
|
crfree(newcred);
|
|
return (error);
|
|
}
|
|
|
|
crcopy(newcred, oldcred);
|
|
if (egid != (gid_t)-1 && oldcred->cr_groups[0] != egid) {
|
|
change_egid(newcred, egid);
|
|
setsugid(p);
|
|
}
|
|
if (rgid != (gid_t)-1 && oldcred->cr_rgid != rgid) {
|
|
change_rgid(newcred, rgid);
|
|
setsugid(p);
|
|
}
|
|
if ((rgid != (gid_t)-1 || newcred->cr_groups[0] != newcred->cr_rgid) &&
|
|
newcred->cr_svgid != newcred->cr_groups[0]) {
|
|
change_svgid(newcred, newcred->cr_groups[0]);
|
|
setsugid(p);
|
|
}
|
|
p->p_ucred = newcred;
|
|
PROC_UNLOCK(p);
|
|
crfree(oldcred);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* setresuid(ruid, euid, suid) is like setreuid except control over the
|
|
* saved uid is explicit.
|
|
*/
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setresuid_args {
|
|
uid_t ruid;
|
|
uid_t euid;
|
|
uid_t suid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setresuid(register struct thread *td, struct setresuid_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
uid_t euid, ruid, suid;
|
|
struct uidinfo *euip, *ruip;
|
|
int error;
|
|
|
|
euid = uap->euid;
|
|
ruid = uap->ruid;
|
|
suid = uap->suid;
|
|
newcred = crget();
|
|
euip = uifind(euid);
|
|
ruip = uifind(ruid);
|
|
PROC_LOCK(p);
|
|
oldcred = p->p_ucred;
|
|
if (((ruid != (uid_t)-1 && ruid != oldcred->cr_ruid &&
|
|
ruid != oldcred->cr_svuid &&
|
|
ruid != oldcred->cr_uid) ||
|
|
(euid != (uid_t)-1 && euid != oldcred->cr_ruid &&
|
|
euid != oldcred->cr_svuid &&
|
|
euid != oldcred->cr_uid) ||
|
|
(suid != (uid_t)-1 && suid != oldcred->cr_ruid &&
|
|
suid != oldcred->cr_svuid &&
|
|
suid != oldcred->cr_uid)) &&
|
|
(error = suser_cred(oldcred, PRISON_ROOT)) != 0) {
|
|
PROC_UNLOCK(p);
|
|
uifree(ruip);
|
|
uifree(euip);
|
|
crfree(newcred);
|
|
return (error);
|
|
}
|
|
|
|
crcopy(newcred, oldcred);
|
|
if (euid != (uid_t)-1 && oldcred->cr_uid != euid) {
|
|
change_euid(newcred, euip);
|
|
setsugid(p);
|
|
}
|
|
if (ruid != (uid_t)-1 && oldcred->cr_ruid != ruid) {
|
|
change_ruid(newcred, ruip);
|
|
setsugid(p);
|
|
}
|
|
if (suid != (uid_t)-1 && oldcred->cr_svuid != suid) {
|
|
change_svuid(newcred, suid);
|
|
setsugid(p);
|
|
}
|
|
p->p_ucred = newcred;
|
|
PROC_UNLOCK(p);
|
|
uifree(ruip);
|
|
uifree(euip);
|
|
crfree(oldcred);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* setresgid(rgid, egid, sgid) is like setregid except control over the
|
|
* saved gid is explicit.
|
|
*/
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setresgid_args {
|
|
gid_t rgid;
|
|
gid_t egid;
|
|
gid_t sgid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setresgid(register struct thread *td, struct setresgid_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
gid_t egid, rgid, sgid;
|
|
int error;
|
|
|
|
egid = uap->egid;
|
|
rgid = uap->rgid;
|
|
sgid = uap->sgid;
|
|
newcred = crget();
|
|
PROC_LOCK(p);
|
|
oldcred = p->p_ucred;
|
|
if (((rgid != (gid_t)-1 && rgid != oldcred->cr_rgid &&
|
|
rgid != oldcred->cr_svgid &&
|
|
rgid != oldcred->cr_groups[0]) ||
|
|
(egid != (gid_t)-1 && egid != oldcred->cr_rgid &&
|
|
egid != oldcred->cr_svgid &&
|
|
egid != oldcred->cr_groups[0]) ||
|
|
(sgid != (gid_t)-1 && sgid != oldcred->cr_rgid &&
|
|
sgid != oldcred->cr_svgid &&
|
|
sgid != oldcred->cr_groups[0])) &&
|
|
(error = suser_cred(oldcred, PRISON_ROOT)) != 0) {
|
|
PROC_UNLOCK(p);
|
|
crfree(newcred);
|
|
return (error);
|
|
}
|
|
|
|
crcopy(newcred, oldcred);
|
|
if (egid != (gid_t)-1 && oldcred->cr_groups[0] != egid) {
|
|
change_egid(newcred, egid);
|
|
setsugid(p);
|
|
}
|
|
if (rgid != (gid_t)-1 && oldcred->cr_rgid != rgid) {
|
|
change_rgid(newcred, rgid);
|
|
setsugid(p);
|
|
}
|
|
if (sgid != (gid_t)-1 && oldcred->cr_svgid != sgid) {
|
|
change_svgid(newcred, sgid);
|
|
setsugid(p);
|
|
}
|
|
p->p_ucred = newcred;
|
|
PROC_UNLOCK(p);
|
|
crfree(oldcred);
|
|
return (0);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getresuid_args {
|
|
uid_t *ruid;
|
|
uid_t *euid;
|
|
uid_t *suid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
getresuid(register struct thread *td, struct getresuid_args *uap)
|
|
{
|
|
struct ucred *cred;
|
|
int error1 = 0, error2 = 0, error3 = 0;
|
|
|
|
cred = td->td_ucred;
|
|
if (uap->ruid)
|
|
error1 = copyout(&cred->cr_ruid,
|
|
uap->ruid, sizeof(cred->cr_ruid));
|
|
if (uap->euid)
|
|
error2 = copyout(&cred->cr_uid,
|
|
uap->euid, sizeof(cred->cr_uid));
|
|
if (uap->suid)
|
|
error3 = copyout(&cred->cr_svuid,
|
|
uap->suid, sizeof(cred->cr_svuid));
|
|
return (error1 ? error1 : error2 ? error2 : error3);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getresgid_args {
|
|
gid_t *rgid;
|
|
gid_t *egid;
|
|
gid_t *sgid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
getresgid(register struct thread *td, struct getresgid_args *uap)
|
|
{
|
|
struct ucred *cred;
|
|
int error1 = 0, error2 = 0, error3 = 0;
|
|
|
|
cred = td->td_ucred;
|
|
if (uap->rgid)
|
|
error1 = copyout(&cred->cr_rgid,
|
|
uap->rgid, sizeof(cred->cr_rgid));
|
|
if (uap->egid)
|
|
error2 = copyout(&cred->cr_groups[0],
|
|
uap->egid, sizeof(cred->cr_groups[0]));
|
|
if (uap->sgid)
|
|
error3 = copyout(&cred->cr_svgid,
|
|
uap->sgid, sizeof(cred->cr_svgid));
|
|
return (error1 ? error1 : error2 ? error2 : error3);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct issetugid_args {
|
|
int dummy;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
issetugid(register struct thread *td, struct issetugid_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
|
|
/*
|
|
* Note: OpenBSD sets a P_SUGIDEXEC flag set at execve() time,
|
|
* we use P_SUGID because we consider changing the owners as
|
|
* "tainting" as well.
|
|
* This is significant for procs that start as root and "become"
|
|
* a user without an exec - programs cannot know *everything*
|
|
* that libc *might* have put in their data segment.
|
|
*/
|
|
PROC_LOCK(p);
|
|
td->td_retval[0] = (p->p_flag & P_SUGID) ? 1 : 0;
|
|
PROC_UNLOCK(p);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
int
|
|
__setugid(struct thread *td, struct __setugid_args *uap)
|
|
{
|
|
#ifdef REGRESSION
|
|
struct proc *p;
|
|
|
|
p = td->td_proc;
|
|
switch (uap->flag) {
|
|
case 0:
|
|
PROC_LOCK(p);
|
|
p->p_flag &= ~P_SUGID;
|
|
PROC_UNLOCK(p);
|
|
return (0);
|
|
case 1:
|
|
PROC_LOCK(p);
|
|
p->p_flag |= P_SUGID;
|
|
PROC_UNLOCK(p);
|
|
return (0);
|
|
default:
|
|
return (EINVAL);
|
|
}
|
|
#else /* !REGRESSION */
|
|
|
|
return (ENOSYS);
|
|
#endif /* REGRESSION */
|
|
}
|
|
|
|
/*
|
|
* Check if gid is a member of the group set.
|
|
*
|
|
* MPSAFE (cred must be held)
|
|
*/
|
|
int
|
|
groupmember(gid_t gid, struct ucred *cred)
|
|
{
|
|
register gid_t *gp;
|
|
gid_t *egp;
|
|
|
|
egp = &(cred->cr_groups[cred->cr_ngroups]);
|
|
for (gp = cred->cr_groups; gp < egp; gp++)
|
|
if (*gp == gid)
|
|
return (1);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* `suser_enabled' (which can be set by the security.suser_enabled
|
|
* sysctl) determines whether the system 'super-user' policy is in effect.
|
|
* If it is nonzero, an effective uid of 0 connotes special privilege,
|
|
* overriding many mandatory and discretionary protections. If it is zero,
|
|
* uid 0 is offered no special privilege in the kernel security policy.
|
|
* Setting it to zero may seriously impact the functionality of many
|
|
* existing userland programs, and should not be done without careful
|
|
* consideration of the consequences.
|
|
*/
|
|
int suser_enabled = 1;
|
|
SYSCTL_INT(_security_bsd, OID_AUTO, suser_enabled, CTLFLAG_RW,
|
|
&suser_enabled, 0, "processes with uid 0 have privilege");
|
|
TUNABLE_INT("security.bsd.suser_enabled", &suser_enabled);
|
|
|
|
/*
|
|
* Test whether the specified credentials imply "super-user" privilege.
|
|
* Return 0 or EPERM.
|
|
*/
|
|
int
|
|
suser_cred(struct ucred *cred, int flag)
|
|
{
|
|
|
|
if (!suser_enabled)
|
|
return (EPERM);
|
|
if (((flag & SUSER_RUID) ? cred->cr_ruid : cred->cr_uid) != 0)
|
|
return (EPERM);
|
|
if (jailed(cred) && !(flag & PRISON_ROOT))
|
|
return (EPERM);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Shortcut to hide contents of struct td and struct proc from the
|
|
* caller, promoting binary compatibility.
|
|
*/
|
|
int
|
|
suser(struct thread *td)
|
|
{
|
|
|
|
#ifdef INVARIANTS
|
|
if (td != curthread) {
|
|
printf("suser: thread %p (%d %s) != curthread %p (%d %s)\n",
|
|
td, td->td_proc->p_pid, td->td_proc->p_comm,
|
|
curthread, curthread->td_proc->p_pid,
|
|
curthread->td_proc->p_comm);
|
|
#ifdef KDB
|
|
kdb_backtrace();
|
|
#endif
|
|
}
|
|
#endif
|
|
return (suser_cred(td->td_ucred, 0));
|
|
}
|
|
|
|
/*
|
|
* Test the active securelevel against a given level. securelevel_gt()
|
|
* implements (securelevel > level). securelevel_ge() implements
|
|
* (securelevel >= level). Note that the logic is inverted -- these
|
|
* functions return EPERM on "success" and 0 on "failure".
|
|
*
|
|
* MPSAFE
|
|
*/
|
|
int
|
|
securelevel_gt(struct ucred *cr, int level)
|
|
{
|
|
int active_securelevel;
|
|
|
|
active_securelevel = securelevel;
|
|
KASSERT(cr != NULL, ("securelevel_gt: null cr"));
|
|
if (cr->cr_prison != NULL) {
|
|
mtx_lock(&cr->cr_prison->pr_mtx);
|
|
active_securelevel = imax(cr->cr_prison->pr_securelevel,
|
|
active_securelevel);
|
|
mtx_unlock(&cr->cr_prison->pr_mtx);
|
|
}
|
|
return (active_securelevel > level ? EPERM : 0);
|
|
}
|
|
|
|
int
|
|
securelevel_ge(struct ucred *cr, int level)
|
|
{
|
|
int active_securelevel;
|
|
|
|
active_securelevel = securelevel;
|
|
KASSERT(cr != NULL, ("securelevel_ge: null cr"));
|
|
if (cr->cr_prison != NULL) {
|
|
mtx_lock(&cr->cr_prison->pr_mtx);
|
|
active_securelevel = imax(cr->cr_prison->pr_securelevel,
|
|
active_securelevel);
|
|
mtx_unlock(&cr->cr_prison->pr_mtx);
|
|
}
|
|
return (active_securelevel >= level ? EPERM : 0);
|
|
}
|
|
|
|
/*
|
|
* 'see_other_uids' determines whether or not visibility of processes
|
|
* and sockets with credentials holding different real uids is possible
|
|
* using a variety of system MIBs.
|
|
* XXX: data declarations should be together near the beginning of the file.
|
|
*/
|
|
static int see_other_uids = 1;
|
|
SYSCTL_INT(_security_bsd, OID_AUTO, see_other_uids, CTLFLAG_RW,
|
|
&see_other_uids, 0,
|
|
"Unprivileged processes may see subjects/objects with different real uid");
|
|
|
|
/*-
|
|
* Determine if u1 "can see" the subject specified by u2, according to the
|
|
* 'see_other_uids' policy.
|
|
* Returns: 0 for permitted, ESRCH otherwise
|
|
* Locks: none
|
|
* References: *u1 and *u2 must not change during the call
|
|
* u1 may equal u2, in which case only one reference is required
|
|
*/
|
|
static int
|
|
cr_seeotheruids(struct ucred *u1, struct ucred *u2)
|
|
{
|
|
|
|
if (!see_other_uids && u1->cr_ruid != u2->cr_ruid) {
|
|
if (suser_cred(u1, PRISON_ROOT) != 0)
|
|
return (ESRCH);
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* 'see_other_gids' determines whether or not visibility of processes
|
|
* and sockets with credentials holding different real gids is possible
|
|
* using a variety of system MIBs.
|
|
* XXX: data declarations should be together near the beginning of the file.
|
|
*/
|
|
static int see_other_gids = 1;
|
|
SYSCTL_INT(_security_bsd, OID_AUTO, see_other_gids, CTLFLAG_RW,
|
|
&see_other_gids, 0,
|
|
"Unprivileged processes may see subjects/objects with different real gid");
|
|
|
|
/*
|
|
* Determine if u1 can "see" the subject specified by u2, according to the
|
|
* 'see_other_gids' policy.
|
|
* Returns: 0 for permitted, ESRCH otherwise
|
|
* Locks: none
|
|
* References: *u1 and *u2 must not change during the call
|
|
* u1 may equal u2, in which case only one reference is required
|
|
*/
|
|
static int
|
|
cr_seeothergids(struct ucred *u1, struct ucred *u2)
|
|
{
|
|
int i, match;
|
|
|
|
if (!see_other_gids) {
|
|
match = 0;
|
|
for (i = 0; i < u1->cr_ngroups; i++) {
|
|
if (groupmember(u1->cr_groups[i], u2))
|
|
match = 1;
|
|
if (match)
|
|
break;
|
|
}
|
|
if (!match) {
|
|
if (suser_cred(u1, PRISON_ROOT) != 0)
|
|
return (ESRCH);
|
|
}
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
/*-
|
|
* Determine if u1 "can see" the subject specified by u2.
|
|
* Returns: 0 for permitted, an errno value otherwise
|
|
* Locks: none
|
|
* References: *u1 and *u2 must not change during the call
|
|
* u1 may equal u2, in which case only one reference is required
|
|
*/
|
|
int
|
|
cr_cansee(struct ucred *u1, struct ucred *u2)
|
|
{
|
|
int error;
|
|
|
|
if ((error = prison_check(u1, u2)))
|
|
return (error);
|
|
#ifdef MAC
|
|
if ((error = mac_check_cred_visible(u1, u2)))
|
|
return (error);
|
|
#endif
|
|
if ((error = cr_seeotheruids(u1, u2)))
|
|
return (error);
|
|
if ((error = cr_seeothergids(u1, u2)))
|
|
return (error);
|
|
return (0);
|
|
}
|
|
|
|
/*-
|
|
* Determine if td "can see" the subject specified by p.
|
|
* Returns: 0 for permitted, an errno value otherwise
|
|
* Locks: Sufficient locks to protect p->p_ucred must be held. td really
|
|
* should be curthread.
|
|
* References: td and p must be valid for the lifetime of the call
|
|
*/
|
|
int
|
|
p_cansee(struct thread *td, struct proc *p)
|
|
{
|
|
|
|
/* Wrap cr_cansee() for all functionality. */
|
|
KASSERT(td == curthread, ("%s: td not curthread", __func__));
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
return (cr_cansee(td->td_ucred, p->p_ucred));
|
|
}
|
|
|
|
/*
|
|
* 'conservative_signals' prevents the delivery of a broad class of
|
|
* signals by unprivileged processes to processes that have changed their
|
|
* credentials since the last invocation of execve(). This can prevent
|
|
* the leakage of cached information or retained privileges as a result
|
|
* of a common class of signal-related vulnerabilities. However, this
|
|
* may interfere with some applications that expect to be able to
|
|
* deliver these signals to peer processes after having given up
|
|
* privilege.
|
|
*/
|
|
static int conservative_signals = 1;
|
|
SYSCTL_INT(_security_bsd, OID_AUTO, conservative_signals, CTLFLAG_RW,
|
|
&conservative_signals, 0, "Unprivileged processes prevented from "
|
|
"sending certain signals to processes whose credentials have changed");
|
|
/*-
|
|
* Determine whether cred may deliver the specified signal to proc.
|
|
* Returns: 0 for permitted, an errno value otherwise.
|
|
* Locks: A lock must be held for proc.
|
|
* References: cred and proc must be valid for the lifetime of the call.
|
|
*/
|
|
int
|
|
cr_cansignal(struct ucred *cred, struct proc *proc, int signum)
|
|
{
|
|
int error;
|
|
|
|
PROC_LOCK_ASSERT(proc, MA_OWNED);
|
|
/*
|
|
* Jail semantics limit the scope of signalling to proc in the
|
|
* same jail as cred, if cred is in jail.
|
|
*/
|
|
error = prison_check(cred, proc->p_ucred);
|
|
if (error)
|
|
return (error);
|
|
#ifdef MAC
|
|
if ((error = mac_check_proc_signal(cred, proc, signum)))
|
|
return (error);
|
|
#endif
|
|
if ((error = cr_seeotheruids(cred, proc->p_ucred)))
|
|
return (error);
|
|
if ((error = cr_seeothergids(cred, proc->p_ucred)))
|
|
return (error);
|
|
|
|
/*
|
|
* UNIX signal semantics depend on the status of the P_SUGID
|
|
* bit on the target process. If the bit is set, then additional
|
|
* restrictions are placed on the set of available signals.
|
|
*/
|
|
if (conservative_signals && (proc->p_flag & P_SUGID)) {
|
|
switch (signum) {
|
|
case 0:
|
|
case SIGKILL:
|
|
case SIGINT:
|
|
case SIGTERM:
|
|
case SIGALRM:
|
|
case SIGSTOP:
|
|
case SIGTTIN:
|
|
case SIGTTOU:
|
|
case SIGTSTP:
|
|
case SIGHUP:
|
|
case SIGUSR1:
|
|
case SIGUSR2:
|
|
/*
|
|
* Generally, permit job and terminal control
|
|
* signals.
|
|
*/
|
|
break;
|
|
default:
|
|
/* Not permitted without privilege. */
|
|
error = suser_cred(cred, PRISON_ROOT);
|
|
if (error)
|
|
return (error);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Generally, the target credential's ruid or svuid must match the
|
|
* subject credential's ruid or euid.
|
|
*/
|
|
if (cred->cr_ruid != proc->p_ucred->cr_ruid &&
|
|
cred->cr_ruid != proc->p_ucred->cr_svuid &&
|
|
cred->cr_uid != proc->p_ucred->cr_ruid &&
|
|
cred->cr_uid != proc->p_ucred->cr_svuid) {
|
|
/* Not permitted without privilege. */
|
|
error = suser_cred(cred, PRISON_ROOT);
|
|
if (error)
|
|
return (error);
|
|
}
|
|
|
|
return (0);
|
|
}
|
|
|
|
|
|
/*-
|
|
* Determine whether td may deliver the specified signal to p.
|
|
* Returns: 0 for permitted, an errno value otherwise
|
|
* Locks: Sufficient locks to protect various components of td and p
|
|
* must be held. td must be curthread, and a lock must be
|
|
* held for p.
|
|
* References: td and p must be valid for the lifetime of the call
|
|
*/
|
|
int
|
|
p_cansignal(struct thread *td, struct proc *p, int signum)
|
|
{
|
|
|
|
KASSERT(td == curthread, ("%s: td not curthread", __func__));
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
if (td->td_proc == p)
|
|
return (0);
|
|
|
|
/*
|
|
* UNIX signalling semantics require that processes in the same
|
|
* session always be able to deliver SIGCONT to one another,
|
|
* overriding the remaining protections.
|
|
*/
|
|
/* XXX: This will require an additional lock of some sort. */
|
|
if (signum == SIGCONT && td->td_proc->p_session == p->p_session)
|
|
return (0);
|
|
|
|
return (cr_cansignal(td->td_ucred, p, signum));
|
|
}
|
|
|
|
/*-
|
|
* Determine whether td may reschedule p.
|
|
* Returns: 0 for permitted, an errno value otherwise
|
|
* Locks: Sufficient locks to protect various components of td and p
|
|
* must be held. td must be curthread, and a lock must
|
|
* be held for p.
|
|
* References: td and p must be valid for the lifetime of the call
|
|
*/
|
|
int
|
|
p_cansched(struct thread *td, struct proc *p)
|
|
{
|
|
int error;
|
|
|
|
KASSERT(td == curthread, ("%s: td not curthread", __func__));
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
if (td->td_proc == p)
|
|
return (0);
|
|
if ((error = prison_check(td->td_ucred, p->p_ucred)))
|
|
return (error);
|
|
#ifdef MAC
|
|
if ((error = mac_check_proc_sched(td->td_ucred, p)))
|
|
return (error);
|
|
#endif
|
|
if ((error = cr_seeotheruids(td->td_ucred, p->p_ucred)))
|
|
return (error);
|
|
if ((error = cr_seeothergids(td->td_ucred, p->p_ucred)))
|
|
return (error);
|
|
if (td->td_ucred->cr_ruid == p->p_ucred->cr_ruid)
|
|
return (0);
|
|
if (td->td_ucred->cr_uid == p->p_ucred->cr_ruid)
|
|
return (0);
|
|
if (suser_cred(td->td_ucred, PRISON_ROOT) == 0)
|
|
return (0);
|
|
|
|
#ifdef CAPABILITIES
|
|
if (!cap_check(NULL, td, CAP_SYS_NICE, PRISON_ROOT))
|
|
return (0);
|
|
#endif
|
|
|
|
return (EPERM);
|
|
}
|
|
|
|
/*
|
|
* The 'unprivileged_proc_debug' flag may be used to disable a variety of
|
|
* unprivileged inter-process debugging services, including some procfs
|
|
* functionality, ptrace(), and ktrace(). In the past, inter-process
|
|
* debugging has been involved in a variety of security problems, and sites
|
|
* not requiring the service might choose to disable it when hardening
|
|
* systems.
|
|
*
|
|
* XXX: Should modifying and reading this variable require locking?
|
|
* XXX: data declarations should be together near the beginning of the file.
|
|
*/
|
|
static int unprivileged_proc_debug = 1;
|
|
SYSCTL_INT(_security_bsd, OID_AUTO, unprivileged_proc_debug, CTLFLAG_RW,
|
|
&unprivileged_proc_debug, 0,
|
|
"Unprivileged processes may use process debugging facilities");
|
|
|
|
/*-
|
|
* Determine whether td may debug p.
|
|
* Returns: 0 for permitted, an errno value otherwise
|
|
* Locks: Sufficient locks to protect various components of td and p
|
|
* must be held. td must be curthread, and a lock must
|
|
* be held for p.
|
|
* References: td and p must be valid for the lifetime of the call
|
|
*/
|
|
int
|
|
p_candebug(struct thread *td, struct proc *p)
|
|
{
|
|
int credentialchanged, error, grpsubset, i, uidsubset;
|
|
|
|
KASSERT(td == curthread, ("%s: td not curthread", __func__));
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
if (!unprivileged_proc_debug) {
|
|
error = suser_cred(td->td_ucred, PRISON_ROOT);
|
|
if (error)
|
|
return (error);
|
|
}
|
|
if (td->td_proc == p)
|
|
return (0);
|
|
if ((error = prison_check(td->td_ucred, p->p_ucred)))
|
|
return (error);
|
|
#ifdef MAC
|
|
if ((error = mac_check_proc_debug(td->td_ucred, p)))
|
|
return (error);
|
|
#endif
|
|
if ((error = cr_seeotheruids(td->td_ucred, p->p_ucred)))
|
|
return (error);
|
|
if ((error = cr_seeothergids(td->td_ucred, p->p_ucred)))
|
|
return (error);
|
|
|
|
/*
|
|
* Is p's group set a subset of td's effective group set? This
|
|
* includes p's egid, group access list, rgid, and svgid.
|
|
*/
|
|
grpsubset = 1;
|
|
for (i = 0; i < p->p_ucred->cr_ngroups; i++) {
|
|
if (!groupmember(p->p_ucred->cr_groups[i], td->td_ucred)) {
|
|
grpsubset = 0;
|
|
break;
|
|
}
|
|
}
|
|
grpsubset = grpsubset &&
|
|
groupmember(p->p_ucred->cr_rgid, td->td_ucred) &&
|
|
groupmember(p->p_ucred->cr_svgid, td->td_ucred);
|
|
|
|
/*
|
|
* Are the uids present in p's credential equal to td's
|
|
* effective uid? This includes p's euid, svuid, and ruid.
|
|
*/
|
|
uidsubset = (td->td_ucred->cr_uid == p->p_ucred->cr_uid &&
|
|
td->td_ucred->cr_uid == p->p_ucred->cr_svuid &&
|
|
td->td_ucred->cr_uid == p->p_ucred->cr_ruid);
|
|
|
|
/*
|
|
* Has the credential of the process changed since the last exec()?
|
|
*/
|
|
credentialchanged = (p->p_flag & P_SUGID);
|
|
|
|
/*
|
|
* If p's gids aren't a subset, or the uids aren't a subset,
|
|
* or the credential has changed, require appropriate privilege
|
|
* for td to debug p. For POSIX.1e capabilities, this will
|
|
* require CAP_SYS_PTRACE.
|
|
*/
|
|
if (!grpsubset || !uidsubset || credentialchanged) {
|
|
error = suser_cred(td->td_ucred, PRISON_ROOT);
|
|
if (error)
|
|
return (error);
|
|
}
|
|
|
|
/* Can't trace init when securelevel > 0. */
|
|
if (p == initproc) {
|
|
error = securelevel_gt(td->td_ucred, 0);
|
|
if (error)
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Can't trace a process that's currently exec'ing.
|
|
* XXX: Note, this is not a security policy decision, it's a
|
|
* basic correctness/functionality decision. Therefore, this check
|
|
* should be moved to the caller's of p_candebug().
|
|
*/
|
|
if ((p->p_flag & P_INEXEC) != 0)
|
|
return (EAGAIN);
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*-
|
|
* Determine whether the subject represented by cred can "see" a socket.
|
|
* Returns: 0 for permitted, ENOENT otherwise.
|
|
*/
|
|
int
|
|
cr_canseesocket(struct ucred *cred, struct socket *so)
|
|
{
|
|
int error;
|
|
|
|
error = prison_check(cred, so->so_cred);
|
|
if (error)
|
|
return (ENOENT);
|
|
#ifdef MAC
|
|
SOCK_LOCK(so);
|
|
error = mac_check_socket_visible(cred, so);
|
|
SOCK_UNLOCK(so);
|
|
if (error)
|
|
return (error);
|
|
#endif
|
|
if (cr_seeotheruids(cred, so->so_cred))
|
|
return (ENOENT);
|
|
if (cr_seeothergids(cred, so->so_cred))
|
|
return (ENOENT);
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Allocate a zeroed cred structure.
|
|
* MPSAFE
|
|
*/
|
|
struct ucred *
|
|
crget(void)
|
|
{
|
|
register struct ucred *cr;
|
|
|
|
MALLOC(cr, struct ucred *, sizeof(*cr), M_CRED, M_WAITOK | M_ZERO);
|
|
cr->cr_ref = 1;
|
|
cr->cr_mtxp = mtx_pool_find(mtxpool_sleep, cr);
|
|
#ifdef MAC
|
|
mac_init_cred(cr);
|
|
#endif
|
|
return (cr);
|
|
}
|
|
|
|
/*
|
|
* Claim another reference to a ucred structure.
|
|
* MPSAFE
|
|
*/
|
|
struct ucred *
|
|
crhold(struct ucred *cr)
|
|
{
|
|
|
|
mtx_lock(cr->cr_mtxp);
|
|
cr->cr_ref++;
|
|
mtx_unlock(cr->cr_mtxp);
|
|
return (cr);
|
|
}
|
|
|
|
/*
|
|
* Free a cred structure.
|
|
* Throws away space when ref count gets to 0.
|
|
* MPSAFE
|
|
*/
|
|
void
|
|
crfree(struct ucred *cr)
|
|
{
|
|
struct mtx *mtxp = cr->cr_mtxp;
|
|
|
|
mtx_lock(mtxp);
|
|
KASSERT(cr->cr_ref > 0, ("bad ucred refcount: %d", cr->cr_ref));
|
|
if (--cr->cr_ref == 0) {
|
|
mtx_unlock(mtxp);
|
|
/*
|
|
* Some callers of crget(), such as nfs_statfs(),
|
|
* allocate a temporary credential, but don't
|
|
* allocate a uidinfo structure.
|
|
*/
|
|
if (cr->cr_uidinfo != NULL)
|
|
uifree(cr->cr_uidinfo);
|
|
if (cr->cr_ruidinfo != NULL)
|
|
uifree(cr->cr_ruidinfo);
|
|
/*
|
|
* Free a prison, if any.
|
|
*/
|
|
if (jailed(cr))
|
|
prison_free(cr->cr_prison);
|
|
#ifdef MAC
|
|
mac_destroy_cred(cr);
|
|
#endif
|
|
FREE(cr, M_CRED);
|
|
} else {
|
|
mtx_unlock(mtxp);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Check to see if this ucred is shared.
|
|
* MPSAFE
|
|
*/
|
|
int
|
|
crshared(struct ucred *cr)
|
|
{
|
|
int shared;
|
|
|
|
mtx_lock(cr->cr_mtxp);
|
|
shared = (cr->cr_ref > 1);
|
|
mtx_unlock(cr->cr_mtxp);
|
|
return (shared);
|
|
}
|
|
|
|
/*
|
|
* Copy a ucred's contents from a template. Does not block.
|
|
* MPSAFE
|
|
*/
|
|
void
|
|
crcopy(struct ucred *dest, struct ucred *src)
|
|
{
|
|
|
|
KASSERT(crshared(dest) == 0, ("crcopy of shared ucred"));
|
|
bcopy(&src->cr_startcopy, &dest->cr_startcopy,
|
|
(unsigned)((caddr_t)&src->cr_endcopy -
|
|
(caddr_t)&src->cr_startcopy));
|
|
uihold(dest->cr_uidinfo);
|
|
uihold(dest->cr_ruidinfo);
|
|
if (jailed(dest))
|
|
prison_hold(dest->cr_prison);
|
|
#ifdef MAC
|
|
mac_copy_cred(src, dest);
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Dup cred struct to a new held one.
|
|
* MPSAFE
|
|
*/
|
|
struct ucred *
|
|
crdup(struct ucred *cr)
|
|
{
|
|
struct ucred *newcr;
|
|
|
|
newcr = crget();
|
|
crcopy(newcr, cr);
|
|
return (newcr);
|
|
}
|
|
|
|
#ifdef DIAGNOSTIC
|
|
void
|
|
cred_free_thread(struct thread *td)
|
|
{
|
|
struct ucred *cred;
|
|
|
|
cred = td->td_ucred;
|
|
td->td_ucred = NULL;
|
|
if (cred != NULL)
|
|
crfree(cred);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Fill in a struct xucred based on a struct ucred.
|
|
* MPSAFE
|
|
*/
|
|
void
|
|
cru2x(struct ucred *cr, struct xucred *xcr)
|
|
{
|
|
|
|
bzero(xcr, sizeof(*xcr));
|
|
xcr->cr_version = XUCRED_VERSION;
|
|
xcr->cr_uid = cr->cr_uid;
|
|
xcr->cr_ngroups = cr->cr_ngroups;
|
|
bcopy(cr->cr_groups, xcr->cr_groups, sizeof(cr->cr_groups));
|
|
}
|
|
|
|
/*
|
|
* small routine to swap a thread's current ucred for the correct one
|
|
* taken from the process.
|
|
* MPSAFE
|
|
*/
|
|
void
|
|
cred_update_thread(struct thread *td)
|
|
{
|
|
struct proc *p;
|
|
struct ucred *cred;
|
|
|
|
p = td->td_proc;
|
|
cred = td->td_ucred;
|
|
PROC_LOCK(p);
|
|
td->td_ucred = crhold(p->p_ucred);
|
|
PROC_UNLOCK(p);
|
|
if (cred != NULL)
|
|
crfree(cred);
|
|
}
|
|
|
|
/*
|
|
* Get login name, if available.
|
|
*/
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getlogin_args {
|
|
char *namebuf;
|
|
u_int namelen;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
getlogin(struct thread *td, struct getlogin_args *uap)
|
|
{
|
|
int error;
|
|
char login[MAXLOGNAME];
|
|
struct proc *p = td->td_proc;
|
|
|
|
if (uap->namelen > MAXLOGNAME)
|
|
uap->namelen = MAXLOGNAME;
|
|
PROC_LOCK(p);
|
|
SESS_LOCK(p->p_session);
|
|
bcopy(p->p_session->s_login, login, uap->namelen);
|
|
SESS_UNLOCK(p->p_session);
|
|
PROC_UNLOCK(p);
|
|
error = copyout(login, uap->namebuf, uap->namelen);
|
|
return(error);
|
|
}
|
|
|
|
/*
|
|
* Set login name.
|
|
*/
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setlogin_args {
|
|
char *namebuf;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setlogin(struct thread *td, struct setlogin_args *uap)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
int error;
|
|
char logintmp[MAXLOGNAME];
|
|
|
|
error = suser_cred(td->td_ucred, PRISON_ROOT);
|
|
if (error)
|
|
return (error);
|
|
error = copyinstr(uap->namebuf, logintmp, sizeof(logintmp), NULL);
|
|
if (error == ENAMETOOLONG)
|
|
error = EINVAL;
|
|
else if (!error) {
|
|
PROC_LOCK(p);
|
|
SESS_LOCK(p->p_session);
|
|
(void) memcpy(p->p_session->s_login, logintmp,
|
|
sizeof(logintmp));
|
|
SESS_UNLOCK(p->p_session);
|
|
PROC_UNLOCK(p);
|
|
}
|
|
return (error);
|
|
}
|
|
|
|
void
|
|
setsugid(struct proc *p)
|
|
{
|
|
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
p->p_flag |= P_SUGID;
|
|
if (!(p->p_pfsflags & PF_ISUGID))
|
|
p->p_stops = 0;
|
|
}
|
|
|
|
/*-
|
|
* Change a process's effective uid.
|
|
* Side effects: newcred->cr_uid and newcred->cr_uidinfo will be modified.
|
|
* References: newcred must be an exclusive credential reference for the
|
|
* duration of the call.
|
|
*/
|
|
void
|
|
change_euid(struct ucred *newcred, struct uidinfo *euip)
|
|
{
|
|
|
|
newcred->cr_uid = euip->ui_uid;
|
|
uihold(euip);
|
|
uifree(newcred->cr_uidinfo);
|
|
newcred->cr_uidinfo = euip;
|
|
}
|
|
|
|
/*-
|
|
* Change a process's effective gid.
|
|
* Side effects: newcred->cr_gid will be modified.
|
|
* References: newcred must be an exclusive credential reference for the
|
|
* duration of the call.
|
|
*/
|
|
void
|
|
change_egid(struct ucred *newcred, gid_t egid)
|
|
{
|
|
|
|
newcred->cr_groups[0] = egid;
|
|
}
|
|
|
|
/*-
|
|
* Change a process's real uid.
|
|
* Side effects: newcred->cr_ruid will be updated, newcred->cr_ruidinfo
|
|
* will be updated, and the old and new cr_ruidinfo proc
|
|
* counts will be updated.
|
|
* References: newcred must be an exclusive credential reference for the
|
|
* duration of the call.
|
|
*/
|
|
void
|
|
change_ruid(struct ucred *newcred, struct uidinfo *ruip)
|
|
{
|
|
|
|
(void)chgproccnt(newcred->cr_ruidinfo, -1, 0);
|
|
newcred->cr_ruid = ruip->ui_uid;
|
|
uihold(ruip);
|
|
uifree(newcred->cr_ruidinfo);
|
|
newcred->cr_ruidinfo = ruip;
|
|
(void)chgproccnt(newcred->cr_ruidinfo, 1, 0);
|
|
}
|
|
|
|
/*-
|
|
* Change a process's real gid.
|
|
* Side effects: newcred->cr_rgid will be updated.
|
|
* References: newcred must be an exclusive credential reference for the
|
|
* duration of the call.
|
|
*/
|
|
void
|
|
change_rgid(struct ucred *newcred, gid_t rgid)
|
|
{
|
|
|
|
newcred->cr_rgid = rgid;
|
|
}
|
|
|
|
/*-
|
|
* Change a process's saved uid.
|
|
* Side effects: newcred->cr_svuid will be updated.
|
|
* References: newcred must be an exclusive credential reference for the
|
|
* duration of the call.
|
|
*/
|
|
void
|
|
change_svuid(struct ucred *newcred, uid_t svuid)
|
|
{
|
|
|
|
newcred->cr_svuid = svuid;
|
|
}
|
|
|
|
/*-
|
|
* Change a process's saved gid.
|
|
* Side effects: newcred->cr_svgid will be updated.
|
|
* References: newcred must be an exclusive credential reference for the
|
|
* duration of the call.
|
|
*/
|
|
void
|
|
change_svgid(struct ucred *newcred, gid_t svgid)
|
|
{
|
|
|
|
newcred->cr_svgid = svgid;
|
|
}
|