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Commit 54ad9c46 authored by Al Viro's avatar Al Viro Committed by Thomas Gleixner
Browse files

itimers: Move compat itimer syscalls to native ones 



get rid of set_fs(), sanitize compat copyin/copyout.

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/20170607084241.28657-12-viro@ZenIV.linux.org.uk
parent b0dc1242

include/linux/compat.h

+4 −0
Original line number Diff line number Diff line
@@ -94,6 +94,10 @@ struct compat_itimerval { 
	struct compat_timeval	it_value;

};



struct itimerval;

int get_compat_itimerval(struct itimerval *, const struct compat_itimerval __user *);

int put_compat_itimerval(struct compat_itimerval __user *, const struct itimerval *);



struct compat_tms {

	compat_clock_t		tms_utime;

	compat_clock_t		tms_stime;

kernel/compat.c

+16 −53
Original line number Diff line number Diff line
@@ -217,65 +217,28 @@ int compat_convert_timespec(struct timespec __user **kts, 
	return 0;

}



static inline long get_compat_itimerval(struct itimerval *o,

		struct compat_itimerval __user *i)

int get_compat_itimerval(struct itimerval *o, const struct compat_itimerval __user *i)

{

	return (!access_ok(VERIFY_READ, i, sizeof(*i)) ||

		(__get_user(o->it_interval.tv_sec, &i->it_interval.tv_sec) |

		 __get_user(o->it_interval.tv_usec, &i->it_interval.tv_usec) |

		 __get_user(o->it_value.tv_sec, &i->it_value.tv_sec) |

		 __get_user(o->it_value.tv_usec, &i->it_value.tv_usec)));

}



static inline long put_compat_itimerval(struct compat_itimerval __user *o,

		struct itimerval *i)

{

	return (!access_ok(VERIFY_WRITE, o, sizeof(*o)) ||

		(__put_user(i->it_interval.tv_sec, &o->it_interval.tv_sec) |

		 __put_user(i->it_interval.tv_usec, &o->it_interval.tv_usec) |

		 __put_user(i->it_value.tv_sec, &o->it_value.tv_sec) |

		 __put_user(i->it_value.tv_usec, &o->it_value.tv_usec)));

}



asmlinkage long sys_ni_posix_timers(void);



COMPAT_SYSCALL_DEFINE2(getitimer, int, which,

		struct compat_itimerval __user *, it)

{

	struct itimerval kit;

	int error;



	if (!IS_ENABLED(CONFIG_POSIX_TIMERS))

		return sys_ni_posix_timers();

	struct compat_itimerval v32;



	error = do_getitimer(which, &kit);

	if (!error && put_compat_itimerval(it, &kit))

		error = -EFAULT;

	return error;

	if (copy_from_user(&v32, i, sizeof(struct compat_itimerval)))

		return -EFAULT;

	o->it_interval.tv_sec = v32.it_interval.tv_sec;

	o->it_interval.tv_usec = v32.it_interval.tv_usec;

	o->it_value.tv_sec = v32.it_value.tv_sec;

	o->it_value.tv_usec = v32.it_value.tv_usec;

	return 0;

}



COMPAT_SYSCALL_DEFINE3(setitimer, int, which,

		struct compat_itimerval __user *, in,

		struct compat_itimerval __user *, out)

int put_compat_itimerval(struct compat_itimerval __user *o, const struct itimerval *i)

{

	struct itimerval kin, kout;

	int error;

	struct compat_itimerval v32;



	if (!IS_ENABLED(CONFIG_POSIX_TIMERS))

		return sys_ni_posix_timers();



	if (in) {

		if (get_compat_itimerval(&kin, in))

			return -EFAULT;

	} else

		memset(&kin, 0, sizeof(kin));



	error = do_setitimer(which, &kin, out ? &kout : NULL);

	if (error || !out)

		return error;

	if (put_compat_itimerval(out, &kout))

		return -EFAULT;

	return 0;

	v32.it_interval.tv_sec = i->it_interval.tv_sec;

	v32.it_interval.tv_usec = i->it_interval.tv_usec;

	v32.it_value.tv_sec = i->it_value.tv_sec;

	v32.it_value.tv_usec = i->it_value.tv_usec;

	return copy_to_user(o, &v32, sizeof(struct compat_itimerval)) ? -EFAULT : 0;

}



static compat_clock_t clock_t_to_compat_clock_t(clock_t x)

kernel/time/itimer.c

+38 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
#include <linux/posix-timers.h>

#include <linux/hrtimer.h>

#include <trace/events/timer.h>

#include <linux/compat.h>



#include <linux/uaccess.h>
@@ -116,6 +117,19 @@ SYSCALL_DEFINE2(getitimer, int, which, struct itimerval __user *, value) 
	return error;

}



#ifdef CONFIG_COMPAT

COMPAT_SYSCALL_DEFINE2(getitimer, int, which,

		       struct compat_itimerval __user *, it)

{

	struct itimerval kit;

	int error = do_getitimer(which, &kit);



	if (!error && put_compat_itimerval(it, &kit))

		error = -EFAULT;

	return error;

}

#endif





/*

 * The timer is automagically restarted, when interval != 0
@@ -294,3 +308,27 @@ SYSCALL_DEFINE3(setitimer, int, which, struct itimerval __user *, value, 
		return -EFAULT;

	return 0;

}



#ifdef CONFIG_COMPAT

COMPAT_SYSCALL_DEFINE3(setitimer, int, which,

		       struct compat_itimerval __user *, in,

		       struct compat_itimerval __user *, out)

{

	struct itimerval kin, kout;

	int error;



	if (in) {

		if (get_compat_itimerval(&kin, in))

			return -EFAULT;

	} else {

		memset(&kin, 0, sizeof(kin));

	}



	error = do_setitimer(which, &kin, out ? &kout : NULL);

	if (error || !out)

		return error;

	if (put_compat_itimerval(out, &kout))

		return -EFAULT;

	return 0;

}

#endif

kernel/time/posix-stubs.c

+2 −0
Original line number Diff line number Diff line
@@ -44,6 +44,8 @@ SYS_NI(alarm); 
COMPAT_SYS_NI(clock_adjtime);

COMPAT_SYS_NI(timer_settime);

COMPAT_SYS_NI(timer_gettime);

COMPAT_SYS_NI(getitimer);

COMPAT_SYS_NI(setitimer);



/*

 * We preserve minimal support for CLOCK_REALTIME and CLOCK_MONOTONIC