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itimers: Move compat itimer syscalls to native ones

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

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Thomas 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
This commit is contained in:
Al Viro 2017-06-07 09:42:37 +01:00 committed by Thomas Gleixner
parent b0dc12426e
commit 54ad9c46c2
4 changed files with 62 additions and 55 deletions
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4
include/linux/compat.h
View File

@ -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;

73
kernel/compat.c
View File

@ -217,67 +217,30 @@ 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)));
}
struct compat_itimerval v32;
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();
error = do_getitimer(which, &kit);
if (!error && put_compat_itimerval(it, &kit))
error = -EFAULT;
return error;
}
COMPAT_SYSCALL_DEFINE3(setitimer, int, which,
struct compat_itimerval __user *, in,
struct compat_itimerval __user *, out)
{
struct itimerval kin, kout;
int error;
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))
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;
}
int put_compat_itimerval(struct compat_itimerval __user *o, const struct itimerval *i)
{
struct compat_itimerval v32;
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)
{
return compat_jiffies_to_clock_t(clock_t_to_jiffies(x));

38
kernel/time/itimer.c
View File

@ -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

2
kernel/time/posix-stubs.c
View File

@ -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