Commit edbeda46 authored by Al Viro's avatar Al Viro Committed by Thomas Gleixner
Browse files

time/posix-timers: Move the compat copyouts to the nanosleep implementations 



Turn restart_block.nanosleep.{rmtp,compat_rmtp} into a tagged union (kind =
1 -> native, kind = 2 -> compat, kind = 0 -> nothing) and make the places
doing actual copyout handle compat as well as native (that will become a
helper in the next commit).  Result: compat wrappers, messing with
reassignments, etc. are gone.

[ tglx: Folded in a variant of Peter Zijlstras enum patch ]

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170607084241.28657-6-viro@ZenIV.linux.org.uk
parent 99e6c0e6

include/linux/posix-timers.h

+0 −2
Original line number Diff line number Diff line
@@ -110,8 +110,6 @@ void posix_cpu_timers_exit_group(struct task_struct *task); 
void set_process_cpu_timer(struct task_struct *task, unsigned int clock_idx,

			   u64 *newval, u64 *oldval);



long clock_nanosleep_restart(struct restart_block *restart_block);



void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new);



void posixtimer_rearm(struct siginfo *info);

include/linux/restart_block.h

+13 −2
Original line number Diff line number Diff line
@@ -11,6 +11,14 @@ struct timespec; 
struct compat_timespec;

struct pollfd;



enum timespec_type {

	TT_NONE		= 0,

	TT_NATIVE	= 1,

#ifdef CONFIG_COMPAT

	TT_COMPAT	= 2,

#endif

};



/*

 * System call restart block.

 */
@@ -29,10 +37,13 @@ struct restart_block { 
		/* For nanosleep */

		struct {

			clockid_t clockid;

			enum timespec_type type;

			union {

				struct timespec __user *rmtp;

#ifdef CONFIG_COMPAT

				struct compat_timespec __user *compat_rmtp;

#endif

			};

			u64 expires;

		} nanosleep;

		/* For poll */

kernel/compat.c

+0 −131
Original line number Diff line number Diff line
@@ -213,82 +213,6 @@ int compat_convert_timespec(struct timespec __user **kts, 
	return 0;

}



static long compat_nanosleep_restart(struct restart_block *restart)

{

	struct compat_timespec __user *rmtp;

	struct timespec rmt;

	mm_segment_t oldfs;

	long ret;



	restart->nanosleep.rmtp = (struct timespec __user *) &rmt;

	oldfs = get_fs();

	set_fs(KERNEL_DS);

	ret = hrtimer_nanosleep_restart(restart);

	set_fs(oldfs);



	if (ret == -ERESTART_RESTARTBLOCK) {

		rmtp = restart->nanosleep.compat_rmtp;



		if (rmtp && compat_put_timespec(&rmt, rmtp))

			return -EFAULT;

	}



	return ret;

}



COMPAT_SYSCALL_DEFINE2(nanosleep, struct compat_timespec __user *, rqtp,

		       struct compat_timespec __user *, rmtp)

{

	struct timespec tu, rmt;

	struct timespec64 tu64;

	mm_segment_t oldfs;

	long ret;



	if (compat_get_timespec(&tu, rqtp))

		return -EFAULT;



	tu64 = timespec_to_timespec64(tu);

	if (!timespec64_valid(&tu64))

		return -EINVAL;



	oldfs = get_fs();

	set_fs(KERNEL_DS);

	current->restart_block.nanosleep.rmtp =

				rmtp ? (struct timespec __user *)&rmt : NULL;

	ret = hrtimer_nanosleep(&tu64, HRTIMER_MODE_REL, CLOCK_MONOTONIC);

	set_fs(oldfs);



	/*

	 * hrtimer_nanosleep() can only return 0 or

	 * -ERESTART_RESTARTBLOCK here because:

	 *

	 * - we call it with HRTIMER_MODE_REL and therefor exclude the

	 *   -ERESTARTNOHAND return path.

	 *

	 * - we supply the rmtp argument from the task stack (due to

	 *   the necessary compat conversion. So the update cannot

	 *   fail, which excludes the -EFAULT return path as well. If

	 *   it fails nevertheless we have a bigger problem and wont

	 *   reach this place anymore.

	 *

	 * - if the return value is 0, we do not have to update rmtp

	 *    because there is no remaining time.

	 *

	 * We check for -ERESTART_RESTARTBLOCK nevertheless if the

	 * core implementation decides to return random nonsense.

	 */

	if (ret == -ERESTART_RESTARTBLOCK) {

		struct restart_block *restart = &current->restart_block;



		restart->fn = compat_nanosleep_restart;

		restart->nanosleep.compat_rmtp = rmtp;



		if (rmtp && compat_put_timespec(&rmt, rmtp))

			return -EFAULT;

	}

	return ret;

}



static inline long get_compat_itimerval(struct itimerval *o,

		struct compat_itimerval __user *i)

{
@@ -821,61 +745,6 @@ COMPAT_SYSCALL_DEFINE2(clock_getres, clockid_t, which_clock, 
	return err;

}



static long compat_clock_nanosleep_restart(struct restart_block *restart)

{

	long err;

	mm_segment_t oldfs;

	struct timespec tu;

	struct compat_timespec __user *rmtp = restart->nanosleep.compat_rmtp;



	restart->nanosleep.rmtp = (struct timespec __user *) &tu;

	oldfs = get_fs();

	set_fs(KERNEL_DS);

	err = clock_nanosleep_restart(restart);

	set_fs(oldfs);



	if ((err == -ERESTART_RESTARTBLOCK) && rmtp &&

	    compat_put_timespec(&tu, rmtp))

		return -EFAULT;



	if (err == -ERESTART_RESTARTBLOCK) {

		restart->fn = compat_clock_nanosleep_restart;

		restart->nanosleep.compat_rmtp = rmtp;

	}

	return err;

}



COMPAT_SYSCALL_DEFINE4(clock_nanosleep, clockid_t, which_clock, int, flags,

		       struct compat_timespec __user *, rqtp,

		       struct compat_timespec __user *, rmtp)

{

	long err;

	mm_segment_t oldfs;

	struct timespec in, out;

	struct restart_block *restart;



	if (compat_get_timespec(&in, rqtp))

		return -EFAULT;



	oldfs = get_fs();

	set_fs(KERNEL_DS);

	err = sys_clock_nanosleep(which_clock, flags,

				  (struct timespec __user *) &in,

				  (struct timespec __user *) &out);

	set_fs(oldfs);



	if ((err == -ERESTART_RESTARTBLOCK) && rmtp &&

	    compat_put_timespec(&out, rmtp))

		return -EFAULT;



	if (err == -ERESTART_RESTARTBLOCK) {

		restart = &current->restart_block;

		restart->fn = compat_clock_nanosleep_restart;

		restart->nanosleep.compat_rmtp = rmtp;

	}

	return err;

}



/*

 * We currently only need the following fields from the sigevent

 * structure: sigev_value, sigev_signo, sig_notify and (sometimes

kernel/time/alarmtimer.c

+12 −4
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
#include <linux/posix-timers.h>

#include <linux/workqueue.h>

#include <linux/freezer.h>

#include <linux/compat.h>



#include "posix-timers.h"
@@ -691,7 +692,7 @@ static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm, 
static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp,

				enum alarmtimer_type type)

{

	struct timespec __user *rmtp;

	struct restart_block *restart;

	alarm->data = (void *)current;

	do {

		set_current_state(TASK_INTERRUPTIBLE);
@@ -709,8 +710,8 @@ static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp, 


	if (freezing(current))

		alarmtimer_freezerset(absexp, type);

	rmtp = current->restart_block.nanosleep.rmtp;

	if (rmtp) {

	restart = &current->restart_block;

	if (restart->nanosleep.type != TT_NONE) {

		struct timespec rmt;

		ktime_t rem;
@@ -720,7 +721,14 @@ static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp, 
			return 0;

		rmt = ktime_to_timespec(rem);



		if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))

#ifdef CONFIG_COMPAT

		if (restart->nanosleep.type == TT_COMPAT) {

			if (compat_put_timespec(&rmt,

						restart->nanosleep.compat_rmtp))

				return -EFAULT;

		} else

#endif

		if (copy_to_user(restart->nanosleep.rmtp, &rmt, sizeof(rmt)))

			return -EFAULT;

	}

	return -ERESTART_RESTARTBLOCK;

kernel/time/hrtimer.c

+37 −5
Original line number Diff line number Diff line
@@ -51,6 +51,7 @@ 
#include <linux/sched/debug.h>

#include <linux/timer.h>

#include <linux/freezer.h>

#include <linux/compat.h>



#include <linux/uaccess.h>
@@ -1441,7 +1442,8 @@ EXPORT_SYMBOL_GPL(hrtimer_init_sleeper); 


static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)

{

	struct timespec __user *rmtp;

	struct restart_block *restart;



	hrtimer_init_sleeper(t, current);



	do {
@@ -1461,15 +1463,23 @@ static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mod 
	if (!t->task)

		return 0;



	rmtp = current->restart_block.nanosleep.rmtp;

	if (rmtp) {

		struct timespec rmt;

	restart = &current->restart_block;

	if (restart->nanosleep.type != TT_NONE) {

		ktime_t rem = hrtimer_expires_remaining(&t->timer);

		struct timespec rmt;



		if (rem <= 0)

			return 0;

		rmt = ktime_to_timespec(rem);



		if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))

#ifdef CONFIG_COMPAT

		if (restart->nanosleep.type == TT_COMPAT) {

			if (compat_put_timespec(&rmt,

						restart->nanosleep.compat_rmtp))

				return -EFAULT;

		} else

#endif

		if (copy_to_user(restart->nanosleep.rmtp, &rmt, sizeof(rmt)))

			return -EFAULT;

	}

	return -ERESTART_RESTARTBLOCK;
@@ -1535,10 +1545,32 @@ SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp, 
	if (!timespec64_valid(&tu64))

		return -EINVAL;



	current->restart_block.nanosleep.type = rmtp ? TT_NATIVE : TT_NONE;

	current->restart_block.nanosleep.rmtp = rmtp;

	return hrtimer_nanosleep(&tu64, HRTIMER_MODE_REL, CLOCK_MONOTONIC);

}



#ifdef CONFIG_COMPAT



COMPAT_SYSCALL_DEFINE2(nanosleep, struct compat_timespec __user *, rqtp,

		       struct compat_timespec __user *, rmtp)

{

	struct timespec64 tu64;

	struct timespec tu;



	if (compat_get_timespec(&tu, rqtp))

		return -EFAULT;



	tu64 = timespec_to_timespec64(tu);

	if (!timespec64_valid(&tu64))

		return -EINVAL;



	current->restart_block.nanosleep.type = rmtp ? TT_COMPAT : TT_NONE;

	current->restart_block.nanosleep.compat_rmtp = rmtp;

	return hrtimer_nanosleep(&tu64, HRTIMER_MODE_REL, CLOCK_MONOTONIC);

}

#endif



/*

 * Functions related to boot-time initialization:

 */

CRA Git | Maintained and supported by SUSTech CRA and CCSE