bd78cece5d
- crhold() returns a reference to the ucred whose refcount it bumps. - crcopy() now simply copies the credentials from one credential to another and has no return value. - a new crshared() primitive is added which returns true if a ucred's refcount is > 1 and false (0) otherwise.
1854 lines
40 KiB
C
1854 lines
40 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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* Copyright (c) 2000, 2001 Robert N. M. Watson. 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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*
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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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* 3. All advertising materials mentioning features or use of this software
|
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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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
|
|
* SUCH DAMAGE.
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*
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* @(#)kern_prot.c 8.6 (Berkeley) 1/21/94
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* $FreeBSD$
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|
*/
|
|
|
|
/*
|
|
* System calls related to processes and protection
|
|
*/
|
|
|
|
#include "opt_compat.h"
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|
#include "opt_global.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/kernel.h>
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|
#include <sys/lock.h>
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|
#include <sys/mutex.h>
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|
#include <sys/proc.h>
|
|
#include <sys/sysproto.h>
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|
#include <sys/malloc.h>
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|
#include <sys/pioctl.h>
|
|
#include <sys/resourcevar.h>
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|
#include <sys/sysctl.h>
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|
#include <sys/jail.h>
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|
|
|
static MALLOC_DEFINE(M_CRED, "cred", "credentials");
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|
|
|
SYSCTL_NODE(_kern, OID_AUTO, security, CTLFLAG_RW, 0,
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"Kernel 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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|
* getpid
|
|
*/
|
|
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
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|
getpid(td, uap)
|
|
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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|
|
|
mtx_lock(&Giant);
|
|
td->td_retval[0] = p->p_pid;
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|
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
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|
PROC_LOCK(p);
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|
td->td_retval[1] = p->p_pptr->p_pid;
|
|
PROC_UNLOCK(p);
|
|
#endif
|
|
mtx_unlock(&Giant);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* getppid
|
|
*/
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getppid_args {
|
|
int dummy;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
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|
getppid(td, uap)
|
|
struct thread *td;
|
|
struct getppid_args *uap;
|
|
{
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|
struct proc *p = td->td_proc;
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|
|
|
mtx_lock(&Giant);
|
|
PROC_LOCK(p);
|
|
td->td_retval[0] = p->p_pptr->p_pid;
|
|
PROC_UNLOCK(p);
|
|
mtx_unlock(&Giant);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Get process group ID; note that POSIX getpgrp takes no parameter
|
|
*
|
|
* MP SAFE
|
|
*/
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getpgrp_args {
|
|
int dummy;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
int
|
|
getpgrp(td, uap)
|
|
struct thread *td;
|
|
struct getpgrp_args *uap;
|
|
{
|
|
struct proc *p = td->td_proc;
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|
|
|
mtx_lock(&Giant);
|
|
td->td_retval[0] = p->p_pgrp->pg_id;
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|
mtx_unlock(&Giant);
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|
return (0);
|
|
}
|
|
|
|
/* Get an arbitary pid's process group id */
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getpgid_args {
|
|
pid_t pid;
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|
};
|
|
#endif
|
|
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
int
|
|
getpgid(td, uap)
|
|
struct thread *td;
|
|
struct getpgid_args *uap;
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct proc *pt;
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|
int error = 0;
|
|
|
|
mtx_lock(&Giant);
|
|
if (uap->pid == 0)
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|
td->td_retval[0] = p->p_pgrp->pg_id;
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|
else if ((pt = pfind(uap->pid)) == NULL)
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error = ESRCH;
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|
else {
|
|
error = p_cansee(p, pt);
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|
if (error == 0)
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|
td->td_retval[0] = pt->p_pgrp->pg_id;
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|
PROC_UNLOCK(pt);
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|
}
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|
mtx_unlock(&Giant);
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|
return (error);
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|
}
|
|
|
|
/*
|
|
* Get an arbitary pid's session id.
|
|
*/
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getsid_args {
|
|
pid_t pid;
|
|
};
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|
#endif
|
|
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
int
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|
getsid(td, uap)
|
|
struct thread *td;
|
|
struct getsid_args *uap;
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct proc *pt;
|
|
int error = 0;
|
|
|
|
mtx_lock(&Giant);
|
|
if (uap->pid == 0)
|
|
td->td_retval[0] = p->p_session->s_sid;
|
|
else if ((pt = pfind(uap->pid)) == NULL)
|
|
error = ESRCH;
|
|
else {
|
|
error = p_cansee(p, pt);
|
|
if (error == 0)
|
|
td->td_retval[0] = pt->p_session->s_sid;
|
|
PROC_UNLOCK(pt);
|
|
}
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
|
|
/*
|
|
* getuid() - MP SAFE
|
|
*/
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getuid_args {
|
|
int dummy;
|
|
};
|
|
#endif
|
|
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
getuid(td, uap)
|
|
struct thread *td;
|
|
struct getuid_args *uap;
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
|
|
mtx_lock(&Giant);
|
|
td->td_retval[0] = p->p_ucred->cr_ruid;
|
|
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
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|
td->td_retval[1] = p->p_ucred->cr_uid;
|
|
#endif
|
|
mtx_unlock(&Giant);
|
|
return (0);
|
|
}
|
|
|
|
/*
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|
* geteuid() - MP SAFE
|
|
*/
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct geteuid_args {
|
|
int dummy;
|
|
};
|
|
#endif
|
|
|
|
/* ARGSUSED */
|
|
int
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|
geteuid(td, uap)
|
|
struct thread *td;
|
|
struct geteuid_args *uap;
|
|
{
|
|
mtx_lock(&Giant);
|
|
td->td_retval[0] = td->td_proc->p_ucred->cr_uid;
|
|
mtx_unlock(&Giant);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* getgid() - MP SAFE
|
|
*/
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getgid_args {
|
|
int dummy;
|
|
};
|
|
#endif
|
|
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
getgid(td, uap)
|
|
struct thread *td;
|
|
struct getgid_args *uap;
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
|
|
mtx_lock(&Giant);
|
|
td->td_retval[0] = p->p_ucred->cr_rgid;
|
|
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
|
|
td->td_retval[1] = p->p_ucred->cr_groups[0];
|
|
#endif
|
|
mtx_unlock(&Giant);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Get effective group ID. The "egid" is groups[0], and could be obtained
|
|
* via getgroups. This syscall exists because it is somewhat painful to do
|
|
* correctly in a library function.
|
|
*/
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getegid_args {
|
|
int dummy;
|
|
};
|
|
#endif
|
|
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
getegid(td, uap)
|
|
struct thread *td;
|
|
struct getegid_args *uap;
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
|
|
mtx_lock(&Giant);
|
|
td->td_retval[0] = p->p_ucred->cr_groups[0];
|
|
mtx_unlock(&Giant);
|
|
return (0);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getgroups_args {
|
|
u_int gidsetsize;
|
|
gid_t *gidset;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
int
|
|
getgroups(td, uap)
|
|
struct thread *td;
|
|
register struct getgroups_args *uap;
|
|
{
|
|
struct ucred *cred;
|
|
struct proc *p = td->td_proc;
|
|
u_int ngrp;
|
|
int error = 0;
|
|
|
|
mtx_lock(&Giant);
|
|
cred = p->p_ucred;
|
|
if ((ngrp = uap->gidsetsize) == 0) {
|
|
td->td_retval[0] = cred->cr_ngroups;
|
|
error = 0;
|
|
goto done2;
|
|
}
|
|
if (ngrp < cred->cr_ngroups) {
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
ngrp = cred->cr_ngroups;
|
|
if ((error = copyout((caddr_t)cred->cr_groups,
|
|
(caddr_t)uap->gidset, ngrp * sizeof(gid_t)))) {
|
|
goto done2;
|
|
}
|
|
td->td_retval[0] = ngrp;
|
|
done2:
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setsid_args {
|
|
int dummy;
|
|
};
|
|
#endif
|
|
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setsid(td, uap)
|
|
register struct thread *td;
|
|
struct setsid_args *uap;
|
|
{
|
|
int error;
|
|
struct proc *p = td->td_proc;
|
|
|
|
mtx_lock(&Giant);
|
|
if (p->p_pgid == p->p_pid || pgfind(p->p_pid)) {
|
|
error = EPERM;
|
|
} else {
|
|
(void)enterpgrp(p, p->p_pid, 1);
|
|
td->td_retval[0] = p->p_pid;
|
|
error = 0;
|
|
}
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* set process group (setpgid/old setpgrp)
|
|
*
|
|
* caller does setpgid(targpid, targpgid)
|
|
*
|
|
* pid must be caller or child of caller (ESRCH)
|
|
* if a child
|
|
* pid must be in same session (EPERM)
|
|
* pid can't have done an exec (EACCES)
|
|
* if pgid != pid
|
|
* there must exist some pid in same session having pgid (EPERM)
|
|
* pid must not be session leader (EPERM)
|
|
*/
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setpgid_args {
|
|
int pid; /* target process id */
|
|
int pgid; /* target pgrp id */
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setpgid(td, uap)
|
|
struct thread *td;
|
|
register struct setpgid_args *uap;
|
|
{
|
|
struct proc *curp = td->td_proc;
|
|
register struct proc *targp; /* target process */
|
|
register struct pgrp *pgrp; /* target pgrp */
|
|
int error;
|
|
|
|
if (uap->pgid < 0)
|
|
return (EINVAL);
|
|
|
|
mtx_lock(&Giant);
|
|
|
|
if (uap->pid != 0 && uap->pid != curp->p_pid) {
|
|
if ((targp = pfind(uap->pid)) == NULL || !inferior(targp)) {
|
|
if (targp)
|
|
PROC_UNLOCK(targp);
|
|
error = ESRCH;
|
|
goto done2;
|
|
}
|
|
if ((error = p_cansee(curproc, targp))) {
|
|
PROC_UNLOCK(targp);
|
|
goto done2;
|
|
}
|
|
if (targp->p_pgrp == NULL ||
|
|
targp->p_session != curp->p_session) {
|
|
PROC_UNLOCK(targp);
|
|
error = EPERM;
|
|
goto done2;
|
|
}
|
|
if (targp->p_flag & P_EXEC) {
|
|
PROC_UNLOCK(targp);
|
|
error = EACCES;
|
|
goto done2;
|
|
}
|
|
} else {
|
|
targp = curp;
|
|
PROC_LOCK(curp); /* XXX: not needed */
|
|
}
|
|
if (SESS_LEADER(targp)) {
|
|
PROC_UNLOCK(targp);
|
|
error = EPERM;
|
|
goto done2;
|
|
}
|
|
if (uap->pgid == 0) {
|
|
uap->pgid = targp->p_pid;
|
|
} else if (uap->pgid != targp->p_pid) {
|
|
if ((pgrp = pgfind(uap->pgid)) == 0 ||
|
|
pgrp->pg_session != curp->p_session) {
|
|
PROC_UNLOCK(targp);
|
|
error = EPERM;
|
|
goto done2;
|
|
}
|
|
}
|
|
/* XXX: We should probably hold the lock across enterpgrp. */
|
|
PROC_UNLOCK(targp);
|
|
error = enterpgrp(targp, uap->pgid, 0);
|
|
done2:
|
|
mtx_unlock(&Giant);
|
|
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(td, uap)
|
|
struct thread *td;
|
|
struct setuid_args *uap;
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
uid_t uid;
|
|
int error = 0;
|
|
|
|
uid = uap->uid;
|
|
oldcred = p->p_ucred;
|
|
mtx_lock(&Giant);
|
|
|
|
/*
|
|
* 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 uid's 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_xxx(oldcred, NULL, PRISON_ROOT)))
|
|
goto done2;
|
|
|
|
newcred = crdup(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_xxx(oldcred, NULL, 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, uid);
|
|
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.
|
|
* Copy credentials so other references do not see our changes.
|
|
*/
|
|
if (uid != oldcred->cr_uid) {
|
|
change_euid(newcred, uid);
|
|
setsugid(p);
|
|
}
|
|
p->p_ucred = newcred;
|
|
crfree(oldcred);
|
|
done2:
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct seteuid_args {
|
|
uid_t euid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
seteuid(td, uap)
|
|
struct thread *td;
|
|
struct seteuid_args *uap;
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
uid_t euid;
|
|
int error = 0;
|
|
|
|
euid = uap->euid;
|
|
|
|
mtx_lock(&Giant);
|
|
oldcred = p->p_ucred;
|
|
if (euid != oldcred->cr_ruid && /* allow seteuid(getuid()) */
|
|
euid != oldcred->cr_svuid && /* allow seteuid(saved uid) */
|
|
(error = suser_xxx(oldcred, NULL, PRISON_ROOT))) {
|
|
goto done2;
|
|
}
|
|
/*
|
|
* Everything's okay, do it. Copy credentials so other references do
|
|
* not see our changes.
|
|
*/
|
|
newcred = crdup(oldcred);
|
|
if (oldcred->cr_uid != euid) {
|
|
change_euid(newcred, euid);
|
|
setsugid(p);
|
|
}
|
|
p->p_ucred = newcred;
|
|
crfree(oldcred);
|
|
done2:
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setgid_args {
|
|
gid_t gid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setgid(td, uap)
|
|
struct thread *td;
|
|
struct setgid_args *uap;
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
gid_t gid;
|
|
int error = 0;
|
|
|
|
gid = uap->gid;
|
|
|
|
mtx_lock(&Giant);
|
|
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_xxx(oldcred, NULL, PRISON_ROOT))) {
|
|
goto done2;
|
|
}
|
|
|
|
newcred = crdup(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_xxx(oldcred, NULL, 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;
|
|
crfree(oldcred);
|
|
done2:
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setegid_args {
|
|
gid_t egid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setegid(td, uap)
|
|
struct thread *td;
|
|
struct setegid_args *uap;
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
gid_t egid;
|
|
int error = 0;
|
|
|
|
egid = uap->egid;
|
|
|
|
mtx_lock(&Giant);
|
|
oldcred = p->p_ucred;
|
|
if (egid != oldcred->cr_rgid && /* allow setegid(getgid()) */
|
|
egid != oldcred->cr_svgid && /* allow setegid(saved gid) */
|
|
(error = suser_xxx(oldcred, NULL, PRISON_ROOT))) {
|
|
goto done2;
|
|
}
|
|
newcred = crdup(oldcred);
|
|
if (oldcred->cr_groups[0] != egid) {
|
|
change_egid(newcred, egid);
|
|
setsugid(p);
|
|
}
|
|
p->p_ucred = newcred;
|
|
crfree(oldcred);
|
|
done2:
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setgroups_args {
|
|
u_int gidsetsize;
|
|
gid_t *gidset;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setgroups(td, uap)
|
|
struct thread *td;
|
|
struct setgroups_args *uap;
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
u_int ngrp;
|
|
int error;
|
|
|
|
mtx_lock(&Giant);
|
|
|
|
ngrp = uap->gidsetsize;
|
|
oldcred = p->p_ucred;
|
|
if ((error = suser_xxx(oldcred, NULL, PRISON_ROOT)))
|
|
goto done2;
|
|
if (ngrp > NGROUPS) {
|
|
error = EINVAL;
|
|
goto done2;
|
|
}
|
|
/*
|
|
* XXX A little bit lazy here. We could test if anything has
|
|
* changed before crcopy() and setting P_SUGID.
|
|
*/
|
|
newcred = crdup(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 {
|
|
if ((error = copyin((caddr_t)uap->gidset,
|
|
(caddr_t)newcred->cr_groups, ngrp * sizeof(gid_t)))) {
|
|
crfree(newcred);
|
|
goto done2;
|
|
}
|
|
newcred->cr_ngroups = ngrp;
|
|
}
|
|
setsugid(p);
|
|
p->p_ucred = newcred;
|
|
crfree(oldcred);
|
|
done2:
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setreuid_args {
|
|
uid_t ruid;
|
|
uid_t euid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setreuid(td, uap)
|
|
register struct thread *td;
|
|
struct setreuid_args *uap;
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
uid_t ruid, euid;
|
|
int error = 0;
|
|
|
|
ruid = uap->ruid;
|
|
euid = uap->euid;
|
|
|
|
mtx_lock(&Giant);
|
|
|
|
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_xxx(oldcred, NULL, PRISON_ROOT)) != 0) {
|
|
goto done2;
|
|
}
|
|
newcred = crdup(oldcred);
|
|
if (euid != (uid_t)-1 && oldcred->cr_uid != euid) {
|
|
change_euid(newcred, euid);
|
|
setsugid(p);
|
|
}
|
|
if (ruid != (uid_t)-1 && oldcred->cr_ruid != ruid) {
|
|
change_ruid(newcred, ruid);
|
|
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;
|
|
crfree(oldcred);
|
|
done2:
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setregid_args {
|
|
gid_t rgid;
|
|
gid_t egid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setregid(td, uap)
|
|
register struct thread *td;
|
|
struct setregid_args *uap;
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
gid_t rgid, egid;
|
|
int error = 0;
|
|
|
|
rgid = uap->rgid;
|
|
egid = uap->egid;
|
|
|
|
mtx_lock(&Giant);
|
|
|
|
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_xxx(oldcred, NULL, PRISON_ROOT)) != 0) {
|
|
goto done2;
|
|
}
|
|
|
|
newcred = crdup(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;
|
|
crfree(oldcred);
|
|
done2:
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* 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(td, uap)
|
|
register struct thread *td;
|
|
struct setresuid_args *uap;
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
uid_t ruid, euid, suid;
|
|
int error;
|
|
|
|
ruid = uap->ruid;
|
|
euid = uap->euid;
|
|
suid = uap->suid;
|
|
|
|
mtx_lock(&Giant);
|
|
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_xxx(oldcred, NULL, PRISON_ROOT)) != 0) {
|
|
goto done2;
|
|
}
|
|
|
|
newcred = crdup(oldcred);
|
|
if (euid != (uid_t)-1 && oldcred->cr_uid != euid) {
|
|
change_euid(newcred, euid);
|
|
setsugid(p);
|
|
}
|
|
if (ruid != (uid_t)-1 && oldcred->cr_ruid != ruid) {
|
|
change_ruid(newcred, ruid);
|
|
setsugid(p);
|
|
}
|
|
if (suid != (uid_t)-1 && oldcred->cr_svuid != suid) {
|
|
change_svuid(newcred, suid);
|
|
setsugid(p);
|
|
}
|
|
p->p_ucred = newcred;
|
|
crfree(oldcred);
|
|
error = 0;
|
|
done2:
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* 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(td, uap)
|
|
register struct thread *td;
|
|
struct setresgid_args *uap;
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct ucred *newcred, *oldcred;
|
|
gid_t rgid, egid, sgid;
|
|
int error;
|
|
|
|
rgid = uap->rgid;
|
|
egid = uap->egid;
|
|
sgid = uap->sgid;
|
|
|
|
mtx_lock(&Giant);
|
|
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_xxx(oldcred, NULL, PRISON_ROOT)) != 0) {
|
|
goto done2;
|
|
}
|
|
newcred = crdup(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;
|
|
crfree(oldcred);
|
|
error = 0;
|
|
done2:
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getresuid_args {
|
|
uid_t *ruid;
|
|
uid_t *euid;
|
|
uid_t *suid;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
getresuid(td, uap)
|
|
register struct thread *td;
|
|
struct getresuid_args *uap;
|
|
{
|
|
struct ucred *cred;
|
|
struct proc *p = td->td_proc;
|
|
int error1 = 0, error2 = 0, error3 = 0;
|
|
|
|
mtx_lock(&Giant);
|
|
cred = p->p_ucred;
|
|
|
|
if (uap->ruid)
|
|
error1 = copyout((caddr_t)&cred->cr_ruid,
|
|
(caddr_t)uap->ruid, sizeof(cred->cr_ruid));
|
|
if (uap->euid)
|
|
error2 = copyout((caddr_t)&cred->cr_uid,
|
|
(caddr_t)uap->euid, sizeof(cred->cr_uid));
|
|
if (uap->suid)
|
|
error3 = copyout((caddr_t)&cred->cr_svuid,
|
|
(caddr_t)uap->suid, sizeof(cred->cr_svuid));
|
|
mtx_unlock(&Giant);
|
|
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(td, uap)
|
|
register struct thread *td;
|
|
struct getresgid_args *uap;
|
|
{
|
|
struct ucred *cred;
|
|
struct proc *p = td->td_proc;
|
|
int error1 = 0, error2 = 0, error3 = 0;
|
|
|
|
mtx_lock(&Giant);
|
|
cred = p->p_ucred;
|
|
|
|
if (uap->rgid)
|
|
error1 = copyout((caddr_t)&cred->cr_rgid,
|
|
(caddr_t)uap->rgid, sizeof(cred->cr_rgid));
|
|
if (uap->egid)
|
|
error2 = copyout((caddr_t)&cred->cr_groups[0],
|
|
(caddr_t)uap->egid, sizeof(cred->cr_groups[0]));
|
|
if (uap->sgid)
|
|
error3 = copyout((caddr_t)&cred->cr_svgid,
|
|
(caddr_t)uap->sgid, sizeof(cred->cr_svgid));
|
|
mtx_unlock(&Giant);
|
|
return error1 ? error1 : (error2 ? error2 : error3);
|
|
}
|
|
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct issetugid_args {
|
|
int dummy;
|
|
};
|
|
#endif
|
|
/* ARGSUSED */
|
|
int
|
|
issetugid(td, uap)
|
|
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.
|
|
*/
|
|
td->td_retval[0] = (p->p_flag & P_SUGID) ? 1 : 0;
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
int
|
|
__setugid(td, uap)
|
|
struct thread *td;
|
|
struct __setugid_args *uap;
|
|
{
|
|
#ifdef REGRESSION
|
|
int error = 0;
|
|
|
|
mtx_lock(&Giant);
|
|
switch (uap->flag) {
|
|
case 0:
|
|
td->td_proc->p_flag &= ~P_SUGID;
|
|
break;
|
|
case 1:
|
|
td->td_proc->p_flag |= P_SUGID;
|
|
break;
|
|
default:
|
|
error = EINVAL;
|
|
break;
|
|
}
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
#else /* !REGRESSION */
|
|
return (ENOSYS);
|
|
#endif /* !REGRESSION */
|
|
}
|
|
|
|
/*
|
|
* Check if gid is a member of the group set.
|
|
*/
|
|
int
|
|
groupmember(gid, cred)
|
|
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 kern.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(_kern_security, OID_AUTO, suser_enabled, CTLFLAG_RW,
|
|
&suser_enabled, 0, "processes with uid 0 have privilege");
|
|
|
|
/*
|
|
* Test whether the specified credentials imply "super-user" privilege.
|
|
* Return 0 or EPERM.
|
|
*/
|
|
int
|
|
suser(p)
|
|
struct proc *p;
|
|
{
|
|
return suser_xxx(0, p, 0);
|
|
}
|
|
|
|
/*
|
|
* version for when the thread pointer is available and not the proc.
|
|
* (saves having to include proc.h into every file that needs to do the change.)
|
|
*/
|
|
int
|
|
suser_td(td)
|
|
|
|
struct thread *td;
|
|
{
|
|
return suser_xxx(0, td->td_proc, 0);
|
|
}
|
|
|
|
/*
|
|
* wrapper to use if you have the thread on hand but not the proc.
|
|
*/
|
|
int
|
|
suser_xxx_td(cred, td, flag)
|
|
struct ucred *cred;
|
|
struct thread *td;
|
|
int flag;
|
|
{
|
|
return(suser_xxx(cred, td->td_proc, flag));
|
|
}
|
|
|
|
int
|
|
suser_xxx(cred, proc, flag)
|
|
struct ucred *cred;
|
|
struct proc *proc;
|
|
int flag;
|
|
{
|
|
if (!suser_enabled)
|
|
return (EPERM);
|
|
if (!cred && !proc) {
|
|
printf("suser_xxx(): THINK!\n");
|
|
return (EPERM);
|
|
}
|
|
if (!cred)
|
|
cred = proc->p_ucred;
|
|
if (cred->cr_uid != 0)
|
|
return (EPERM);
|
|
if (jailed(cred) && !(flag & PRISON_ROOT))
|
|
return (EPERM);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Test (local, globale) securelevel values against passed required
|
|
* securelevel. _gt implements (level > securelevel), and _ge implements
|
|
* (level >= securelevel). Returns 0 oer EPERM.
|
|
*
|
|
* cr is permitted to be NULL for the time being, as there were some
|
|
* existing securelevel checks that occurred without a process/credential
|
|
* context. In the future this will be disallowed, so a kernel
|
|
* message is displayed.
|
|
*/
|
|
int
|
|
securelevel_gt(struct ucred *cr, int level)
|
|
{
|
|
|
|
if (cr == NULL) {
|
|
printf("securelevel_gt: cr is NULL\n");
|
|
if (level > securelevel)
|
|
return (0);
|
|
else
|
|
return (EPERM);
|
|
} else if (cr->cr_prison == NULL) {
|
|
if (level > securelevel)
|
|
return (0);
|
|
else
|
|
return (EPERM);
|
|
} else {
|
|
if (level > imax(cr->cr_prison->pr_securelevel, securelevel))
|
|
return (0);
|
|
else
|
|
return (EPERM);
|
|
}
|
|
|
|
}
|
|
|
|
int
|
|
securelevel_ge(struct ucred *cr, int level)
|
|
{
|
|
|
|
if (cr == NULL) {
|
|
printf("securelevel_ge: cr is NULL\n");
|
|
if (level >= securelevel)
|
|
return (0);
|
|
else
|
|
return (EPERM);
|
|
} if (cr->cr_prison == NULL) {
|
|
if (level >= securelevel)
|
|
return (0);
|
|
else
|
|
return (EPERM);
|
|
} else {
|
|
if (level >= imax(cr->cr_prison->pr_securelevel, securelevel))
|
|
return (0);
|
|
else
|
|
return (EPERM);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* kern_security_seeotheruids_permitted determines whether or not visibility
|
|
* of processes and sockets with credentials holding different real uid's
|
|
* is possible using a variety of system MIBs.
|
|
*/
|
|
static int kern_security_seeotheruids_permitted = 1;
|
|
SYSCTL_INT(_kern_security, OID_AUTO, seeotheruids_permitted,
|
|
CTLFLAG_RW, &kern_security_seeotheruids_permitted, 0,
|
|
"Unprivileged processes may see subjects/objects with different real uid");
|
|
|
|
/*-
|
|
* 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 be immutable credentials
|
|
* u1 and u2 must be valid for the lifetime of 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);
|
|
if (!kern_security_seeotheruids_permitted &&
|
|
u1->cr_ruid != u2->cr_ruid) {
|
|
if (suser_xxx(u1, NULL, PRISON_ROOT) != 0)
|
|
return (ESRCH);
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
/*-
|
|
* Determine if p1 "can see" the subject specified by p2.
|
|
* Returns: 0 for permitted, an errno value otherwise
|
|
* Locks: Sufficient locks to protect p1->p_ucred and p2->p_ucred must
|
|
* be held. Normally, p1 will be curproc, and a lock must be held
|
|
* for p2.
|
|
* References: p1 and p2 must be valid for the lifetime of the call
|
|
*/
|
|
int
|
|
p_cansee(struct proc *p1, struct proc *p2)
|
|
{
|
|
|
|
/* Wrap cr_cansee() for all functionality. */
|
|
return (cr_cansee(p1->p_ucred, p2->p_ucred));
|
|
}
|
|
|
|
/*-
|
|
* Determine whether p1 may deliver the specified signal to p2.
|
|
* Returns: 0 for permitted, an errno value otherwise
|
|
* Locks: Sufficient locks to protect various components of p1 and p2
|
|
* must be held. Normally, p1 will be curproc, and a lock must
|
|
* be held for p2.
|
|
* References: p1 and p2 must be valid for the lifetime of the call
|
|
*/
|
|
int
|
|
p_cansignal(struct proc *p1, struct proc *p2, int signum)
|
|
{
|
|
int error;
|
|
|
|
if (p1 == p2)
|
|
return (0);
|
|
|
|
/*
|
|
* Jail semantics limit the scope of signalling to p2 in the same
|
|
* jail as p1, if p1 is in jail.
|
|
*/
|
|
if ((error = prison_check(p1->p_ucred, p2->p_ucred)))
|
|
return (error);
|
|
|
|
/*
|
|
* UNIX signalling semantics require that processes in the same
|
|
* session always be able to deliver SIGCONT to one another,
|
|
* overriding the remaining protections.
|
|
*/
|
|
if (signum == SIGCONT && p1->p_session == p2->p_session)
|
|
return (0);
|
|
|
|
/*
|
|
* 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 (p2->p_flag & P_SUGID) {
|
|
switch (signum) {
|
|
case 0:
|
|
case SIGKILL:
|
|
case SIGINT:
|
|
case SIGTERM:
|
|
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, privilege is required. */
|
|
error = suser_xxx(NULL, p1, PRISON_ROOT);
|
|
if (error)
|
|
return (error);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Generally, the target credential's ruid or svuid must match the
|
|
* subject credential's ruid or euid.
|
|
*/
|
|
if (p1->p_ucred->cr_ruid != p2->p_ucred->cr_ruid &&
|
|
p1->p_ucred->cr_ruid != p2->p_ucred->cr_svuid &&
|
|
p1->p_ucred->cr_uid != p2->p_ucred->cr_ruid &&
|
|
p1->p_ucred->cr_uid != p2->p_ucred->cr_svuid) {
|
|
/* Not permitted, try privilege. */
|
|
error = suser_xxx(NULL, p1, PRISON_ROOT);
|
|
if (error)
|
|
return (error);
|
|
}
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*-
|
|
* Determine whether p1 may reschedule p2
|
|
* Returns: 0 for permitted, an errno value otherwise
|
|
* Locks: Sufficient locks to protect various components of p1 and p2
|
|
* must be held. Normally, p1 will be curproc, and a lock must
|
|
* be held for p2.
|
|
* References: p1 and p2 must be valid for the lifetime of the call
|
|
*/
|
|
int
|
|
p_cansched(struct proc *p1, struct proc *p2)
|
|
{
|
|
int error;
|
|
|
|
if (p1 == p2)
|
|
return (0);
|
|
if ((error = prison_check(p1->p_ucred, p2->p_ucred)))
|
|
return (error);
|
|
if (p1->p_ucred->cr_ruid == p2->p_ucred->cr_ruid)
|
|
return (0);
|
|
if (p1->p_ucred->cr_uid == p2->p_ucred->cr_ruid)
|
|
return (0);
|
|
if (suser_xxx(0, p1, PRISON_ROOT) == 0)
|
|
return (0);
|
|
|
|
#ifdef CAPABILITIES
|
|
if (!cap_check_xxx(0, p1, CAP_SYS_NICE, PRISON_ROOT))
|
|
return (0);
|
|
#endif
|
|
|
|
return (EPERM);
|
|
}
|
|
|
|
/*
|
|
* The kern_unprivileged_procdebug_permitted 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?
|
|
*/
|
|
static int kern_unprivileged_procdebug_permitted = 1;
|
|
SYSCTL_INT(_kern_security, OID_AUTO, unprivileged_procdebug_permitted,
|
|
CTLFLAG_RW, &kern_unprivileged_procdebug_permitted, 0,
|
|
"Unprivileged processes may use process debugging facilities");
|
|
|
|
/*-
|
|
* Determine whether p1 may debug p2.
|
|
* Returns: 0 for permitted, an errno value otherwise
|
|
* Locks: Sufficient locks to protect various components of p1 and p2
|
|
* must be held. Normally, p1 will be curproc, and a lock must
|
|
* be held for p2.
|
|
* References: p1 and p2 must be valid for the lifetime of the call
|
|
*/
|
|
int
|
|
p_candebug(struct proc *p1, struct proc *p2)
|
|
{
|
|
int error;
|
|
|
|
if (!kern_unprivileged_procdebug_permitted) {
|
|
error = suser_xxx(NULL, p1, PRISON_ROOT);
|
|
if (error)
|
|
return (error);
|
|
}
|
|
|
|
if (p1 == p2)
|
|
return (0);
|
|
|
|
if ((error = prison_check(p1->p_ucred, p2->p_ucred)))
|
|
return (error);
|
|
|
|
/*
|
|
* Not owned by you, has done setuid (unless you're root).
|
|
* XXX add a CAP_SYS_PTRACE here?
|
|
*/
|
|
if (p1->p_ucred->cr_uid != p2->p_ucred->cr_uid ||
|
|
p1->p_ucred->cr_uid != p2->p_ucred->cr_svuid ||
|
|
p1->p_ucred->cr_uid != p2->p_ucred->cr_ruid ||
|
|
p2->p_flag & P_SUGID) {
|
|
error = suser_xxx(NULL, p1, PRISON_ROOT);
|
|
if (error)
|
|
return (error);
|
|
}
|
|
|
|
/* can't trace init when securelevel > 0 */
|
|
if (p2->p_pid == 1) {
|
|
error = securelevel_gt(p1->p_ucred, 0);
|
|
if (error)
|
|
return (error);
|
|
}
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Allocate a zeroed cred structure.
|
|
*/
|
|
struct ucred *
|
|
crget()
|
|
{
|
|
register struct ucred *cr;
|
|
|
|
MALLOC(cr, struct ucred *, sizeof(*cr), M_CRED, M_WAITOK | M_ZERO);
|
|
cr->cr_ref = 1;
|
|
mtx_init(&cr->cr_mtx, "ucred", MTX_DEF);
|
|
return (cr);
|
|
}
|
|
|
|
/*
|
|
* Claim another reference to a ucred structure.
|
|
*/
|
|
struct ucred *
|
|
crhold(cr)
|
|
struct ucred *cr;
|
|
{
|
|
|
|
mtx_lock(&cr->cr_mtx);
|
|
cr->cr_ref++;
|
|
mtx_unlock(&cr->cr_mtx);
|
|
return (cr);
|
|
}
|
|
|
|
|
|
/*
|
|
* Free a cred structure.
|
|
* Throws away space when ref count gets to 0.
|
|
*/
|
|
void
|
|
crfree(cr)
|
|
struct ucred *cr;
|
|
{
|
|
|
|
mtx_lock(&cr->cr_mtx);
|
|
KASSERT(cr->cr_ref > 0, ("bad ucred refcount: %d", cr->cr_ref));
|
|
if (--cr->cr_ref == 0) {
|
|
mtx_destroy(&cr->cr_mtx);
|
|
/*
|
|
* 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);
|
|
FREE((caddr_t)cr, M_CRED);
|
|
} else {
|
|
mtx_unlock(&cr->cr_mtx);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Check to see if this ucred is shared.
|
|
*/
|
|
int
|
|
crshared(cr)
|
|
struct ucred *cr;
|
|
{
|
|
int shared;
|
|
|
|
mtx_lock(&cr->cr_mtx);
|
|
shared = (cr->cr_ref > 1);
|
|
mtx_unlock(&cr->cr_mtx);
|
|
return (shared);
|
|
}
|
|
|
|
/*
|
|
* Copy a ucred's contents from a template. Does not block.
|
|
*/
|
|
void
|
|
crcopy(dest, src)
|
|
struct ucred *dest, *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);
|
|
}
|
|
|
|
/*
|
|
* Dup cred struct to a new held one.
|
|
*/
|
|
struct ucred *
|
|
crdup(cr)
|
|
struct ucred *cr;
|
|
{
|
|
struct ucred *newcr;
|
|
|
|
newcr = crget();
|
|
crcopy(newcr, cr);
|
|
return (newcr);
|
|
}
|
|
|
|
/*
|
|
* Get login name, if available.
|
|
*/
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct getlogin_args {
|
|
char *namebuf;
|
|
u_int namelen;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
getlogin(td, uap)
|
|
struct thread *td;
|
|
struct getlogin_args *uap;
|
|
{
|
|
int error;
|
|
struct proc *p = td->td_proc;
|
|
|
|
mtx_lock(&Giant);
|
|
if (uap->namelen > MAXLOGNAME)
|
|
uap->namelen = MAXLOGNAME;
|
|
error = copyout((caddr_t) p->p_pgrp->pg_session->s_login,
|
|
(caddr_t) uap->namebuf, uap->namelen);
|
|
mtx_unlock(&Giant);
|
|
return(error);
|
|
}
|
|
|
|
/*
|
|
* Set login name.
|
|
*/
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct setlogin_args {
|
|
char *namebuf;
|
|
};
|
|
#endif
|
|
/*
|
|
* MPSAFE
|
|
*/
|
|
/* ARGSUSED */
|
|
int
|
|
setlogin(td, uap)
|
|
struct thread *td;
|
|
struct setlogin_args *uap;
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
int error;
|
|
char logintmp[MAXLOGNAME];
|
|
|
|
mtx_lock(&Giant);
|
|
if ((error = suser_xxx(0, p, PRISON_ROOT)))
|
|
goto done2;
|
|
error = copyinstr((caddr_t) uap->namebuf, (caddr_t) logintmp,
|
|
sizeof(logintmp), (size_t *)0);
|
|
if (error == ENAMETOOLONG) {
|
|
error = EINVAL;
|
|
} else if (!error) {
|
|
(void) memcpy(p->p_pgrp->pg_session->s_login, logintmp,
|
|
sizeof(logintmp));
|
|
}
|
|
done2:
|
|
mtx_unlock(&Giant);
|
|
return (error);
|
|
}
|
|
|
|
void
|
|
setsugid(p)
|
|
struct proc *p;
|
|
{
|
|
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(newcred, euid)
|
|
struct ucred *newcred;
|
|
uid_t euid;
|
|
{
|
|
|
|
newcred->cr_uid = euid;
|
|
uifree(newcred->cr_uidinfo);
|
|
newcred->cr_uidinfo = uifind(euid);
|
|
}
|
|
|
|
/*-
|
|
* 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(newcred, 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(newcred, ruid)
|
|
struct ucred *newcred;
|
|
uid_t ruid;
|
|
{
|
|
|
|
(void)chgproccnt(newcred->cr_ruidinfo, -1, 0);
|
|
newcred->cr_ruid = ruid;
|
|
uifree(newcred->cr_ruidinfo);
|
|
newcred->cr_ruidinfo = uifind(ruid);
|
|
(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(newcred, 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(newcred, 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(newcred, svgid)
|
|
struct ucred *newcred;
|
|
gid_t svgid;
|
|
{
|
|
|
|
newcred->cr_svgid = svgid;
|
|
}
|