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freebsd/sys/kern/p1003_1b.c
Florian Walpen 2198221bd9
sched_setscheduler(2): Change realtime privilege check
Check for privilege PRIV_SCHED_SETPOLICY instead of PRIV_SCHED_SET, to
at least make it coherent with what is done at thread creation when
a realtime policy is requested, and have users authorized by
mac_priority(4) pass it.

This change is good enough in practice since it only allows 'root' (as
before) and mac_priority(4)'s authorized users in (the point of this
change), without other side effects.  More changes in this area, to
generally ensure that all privilege checks are consistent, are going to
come as olce's priority revamp project lands.

(olce: Expanded the explanations.)

PR:                     276962
Reported by:            jbeich
Reviewed by:            olce
Approved by:            emaste (mentor)
MFC after:              3 days
Differential Revision:  https://reviews.freebsd.org/D43835
2024-02-14 15:24:11 +01:00

382 lines
8.8 KiB
C

/*-
* SPDX-License-Identifier: BSD-4-Clause
*
* Copyright (c) 1996, 1997, 1998
* HD Associates, Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by HD Associates, Inc
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY HD ASSOCIATES AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL HD ASSOCIATES OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/* p1003_1b: Real Time common code.
*/
#include <sys/cdefs.h>
#include "opt_posix.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/posix4.h>
#include <sys/syscallsubr.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/sysproto.h>
MALLOC_DEFINE(M_P31B, "p1003.1b", "Posix 1003.1B");
/* The system calls return ENOSYS if an entry is called that is not run-time
* supported. I am also logging since some programs start to use this when
* they shouldn't. That will be removed if annoying.
*/
int
syscall_not_present(struct thread *td, const char *s, struct nosys_args *uap)
{
log(LOG_ERR, "cmd %s pid %d tried to use non-present %s\n",
td->td_name, td->td_proc->p_pid, s);
/* a " return nosys(p, uap); " here causes a core dump.
*/
return ENOSYS;
}
#if !defined(_KPOSIX_PRIORITY_SCHEDULING)
/* Not configured but loadable via a module:
*/
static int
sched_attach(void)
{
return 0;
}
SYSCALL_NOT_PRESENT_GEN(sched_setparam)
SYSCALL_NOT_PRESENT_GEN(sched_getparam)
SYSCALL_NOT_PRESENT_GEN(sched_setscheduler)
SYSCALL_NOT_PRESENT_GEN(sched_getscheduler)
SYSCALL_NOT_PRESENT_GEN(sched_yield)
SYSCALL_NOT_PRESENT_GEN(sched_get_priority_max)
SYSCALL_NOT_PRESENT_GEN(sched_get_priority_min)
SYSCALL_NOT_PRESENT_GEN(sched_rr_get_interval)
#else
/* Configured in kernel version:
*/
static struct ksched *ksched;
static int
sched_attach(void)
{
int ret = ksched_attach(&ksched);
if (ret == 0)
p31b_setcfg(CTL_P1003_1B_PRIORITY_SCHEDULING, 200112L);
return ret;
}
int
sys_sched_setparam(struct thread *td, struct sched_setparam_args *uap)
{
struct thread *targettd;
struct proc *targetp;
int e;
struct sched_param sched_param;
e = copyin(uap->param, &sched_param, sizeof(sched_param));
if (e)
return (e);
if (uap->pid == 0) {
targetp = td->td_proc;
targettd = td;
PROC_LOCK(targetp);
} else {
targetp = pfind(uap->pid);
if (targetp == NULL)
return (ESRCH);
targettd = FIRST_THREAD_IN_PROC(targetp);
}
e = kern_sched_setparam(td, targettd, &sched_param);
PROC_UNLOCK(targetp);
return (e);
}
int
kern_sched_setparam(struct thread *td, struct thread *targettd,
struct sched_param *param)
{
struct proc *targetp;
int error;
targetp = targettd->td_proc;
PROC_LOCK_ASSERT(targetp, MA_OWNED);
error = p_cansched(td, targetp);
if (error == 0)
error = ksched_setparam(ksched, targettd,
(const struct sched_param *)param);
return (error);
}
int
sys_sched_getparam(struct thread *td, struct sched_getparam_args *uap)
{
int e;
struct sched_param sched_param;
struct thread *targettd;
struct proc *targetp;
if (uap->pid == 0) {
targetp = td->td_proc;
targettd = td;
PROC_LOCK(targetp);
} else {
targetp = pfind(uap->pid);
if (targetp == NULL) {
return (ESRCH);
}
targettd = FIRST_THREAD_IN_PROC(targetp);
}
e = kern_sched_getparam(td, targettd, &sched_param);
PROC_UNLOCK(targetp);
if (e == 0)
e = copyout(&sched_param, uap->param, sizeof(sched_param));
return (e);
}
int
kern_sched_getparam(struct thread *td, struct thread *targettd,
struct sched_param *param)
{
struct proc *targetp;
int error;
targetp = targettd->td_proc;
PROC_LOCK_ASSERT(targetp, MA_OWNED);
error = p_cansee(td, targetp);
if (error == 0)
error = ksched_getparam(ksched, targettd, param);
return (error);
}
int
sys_sched_setscheduler(struct thread *td, struct sched_setscheduler_args *uap)
{
int e;
struct sched_param sched_param;
struct thread *targettd;
struct proc *targetp;
e = copyin(uap->param, &sched_param, sizeof(sched_param));
if (e)
return (e);
if (uap->pid == 0) {
targetp = td->td_proc;
targettd = td;
PROC_LOCK(targetp);
} else {
targetp = pfind(uap->pid);
if (targetp == NULL)
return (ESRCH);
targettd = FIRST_THREAD_IN_PROC(targetp);
}
e = kern_sched_setscheduler(td, targettd, uap->policy,
&sched_param);
PROC_UNLOCK(targetp);
return (e);
}
int
kern_sched_setscheduler(struct thread *td, struct thread *targettd,
int policy, struct sched_param *param)
{
struct proc *targetp;
int error;
targetp = targettd->td_proc;
PROC_LOCK_ASSERT(targetp, MA_OWNED);
/* Only privileged users are allowed to set a scheduler policy. */
error = priv_check(td, PRIV_SCHED_SETPOLICY);
if (error)
return (error);
error = p_cansched(td, targetp);
if (error == 0)
error = ksched_setscheduler(ksched, targettd, policy,
(const struct sched_param *)param);
return (error);
}
int
sys_sched_getscheduler(struct thread *td, struct sched_getscheduler_args *uap)
{
int e, policy;
struct thread *targettd;
struct proc *targetp;
if (uap->pid == 0) {
targetp = td->td_proc;
targettd = td;
PROC_LOCK(targetp);
} else {
targetp = pfind(uap->pid);
if (targetp == NULL)
return (ESRCH);
targettd = FIRST_THREAD_IN_PROC(targetp);
}
e = kern_sched_getscheduler(td, targettd, &policy);
PROC_UNLOCK(targetp);
if (e == 0)
td->td_retval[0] = policy;
return (e);
}
int
kern_sched_getscheduler(struct thread *td, struct thread *targettd,
int *policy)
{
struct proc *targetp;
int error;
targetp = targettd->td_proc;
PROC_LOCK_ASSERT(targetp, MA_OWNED);
error = p_cansee(td, targetp);
if (error == 0)
error = ksched_getscheduler(ksched, targettd, policy);
return (error);
}
int
sys_sched_yield(struct thread *td, struct sched_yield_args *uap)
{
sched_relinquish(td);
return (0);
}
int
sys_sched_get_priority_max(struct thread *td,
struct sched_get_priority_max_args *uap)
{
int error, prio;
error = ksched_get_priority_max(ksched, uap->policy, &prio);
td->td_retval[0] = prio;
return (error);
}
int
sys_sched_get_priority_min(struct thread *td,
struct sched_get_priority_min_args *uap)
{
int error, prio;
error = ksched_get_priority_min(ksched, uap->policy, &prio);
td->td_retval[0] = prio;
return (error);
}
int
sys_sched_rr_get_interval(struct thread *td,
struct sched_rr_get_interval_args *uap)
{
struct timespec timespec;
int error;
error = kern_sched_rr_get_interval(td, uap->pid, &timespec);
if (error == 0)
error = copyout(&timespec, uap->interval, sizeof(timespec));
return (error);
}
int
kern_sched_rr_get_interval(struct thread *td, pid_t pid,
struct timespec *ts)
{
int e;
struct thread *targettd;
struct proc *targetp;
if (pid == 0) {
targettd = td;
targetp = td->td_proc;
PROC_LOCK(targetp);
} else {
targetp = pfind(pid);
if (targetp == NULL)
return (ESRCH);
targettd = FIRST_THREAD_IN_PROC(targetp);
}
e = kern_sched_rr_get_interval_td(td, targettd, ts);
PROC_UNLOCK(targetp);
return (e);
}
int
kern_sched_rr_get_interval_td(struct thread *td, struct thread *targettd,
struct timespec *ts)
{
struct proc *p;
int error;
p = targettd->td_proc;
PROC_LOCK_ASSERT(p, MA_OWNED);
error = p_cansee(td, p);
if (error == 0)
error = ksched_rr_get_interval(ksched, targettd, ts);
return (error);
}
#endif
static void
p31binit(void *notused)
{
(void) sched_attach();
p31b_setcfg(CTL_P1003_1B_PAGESIZE, PAGE_SIZE);
}
SYSINIT(p31b, SI_SUB_P1003_1B, SI_ORDER_FIRST, p31binit, NULL);