Re: [PATCH 17/23] y2038: time: avoid timespec usage in settimeofday()

From
Thomas Gleixner <hidden>
Date
2019-11-13 21:53:32
Also in
lkml
Reply to
Arnd Bergmann, 2019-11-08
On Fri, 8 Nov 2019, Arnd Bergmann wrote:
quoted hunk ↗ jump to hunk
-SYSCALL_DEFINE2(settimeofday, struct timeval __user *, tv,
+SYSCALL_DEFINE2(settimeofday, struct __kernel_old_timeval __user *, tv,
 		struct timezone __user *, tz)
 {
 	struct timespec64 new_ts;
-	struct timeval user_tv;
 	struct timezone new_tz;
 
 	if (tv) {
-		if (copy_from_user(&user_tv, tv, sizeof(*tv)))
+		if (get_user(new_ts.tv_sec, &tv->tv_sec) ||
+		    get_user(new_ts.tv_nsec, &tv->tv_usec))
 			return -EFAULT;
How is that supposed to be correct on a 32bit kernel?
quoted hunk ↗ jump to hunk
 
-		if (!timeval_valid(&user_tv))
+		if (tv->tv_usec > USEC_PER_SEC)
 			return -EINVAL;
That's incomplete:

static inline bool timeval_valid(const struct timeval *tv)
{
        /* Dates before 1970 are bogus */
        if (tv->tv_sec < 0)
                return false;

	/* Can't have more microseconds then a second */
        if (tv->tv_usec < 0 || tv->tv_usec >= USEC_PER_SEC)
                return false;

        return true;
}

quoted hunk ↗ jump to hunk
 
-		new_ts.tv_sec = user_tv.tv_sec;
-		new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC;
+		new_ts.tv_nsec *= NSEC_PER_USEC;
 	}
 	if (tz) {
 		if (copy_from_user(&new_tz, tz, sizeof(*tz)))
@@ -245,18 +244,17 @@ COMPAT_SYSCALL_DEFINE2(settimeofday, struct old_timeval32 __user *, tv,
 		       struct timezone __user *, tz)
 {
 	struct timespec64 new_ts;
-	struct timeval user_tv;
 	struct timezone new_tz;
 
 	if (tv) {
-		if (compat_get_timeval(&user_tv, tv))
+		if (get_user(new_ts.tv_sec, &tv->tv_sec) ||
+		    get_user(new_ts.tv_nsec, &tv->tv_usec))
 			return -EFAULT;
 
-		if (!timeval_valid(&user_tv))
+		if (new_ts.tv_nsec > USEC_PER_SEC)
 			return -EINVAL;
Ditto.

Thanks,

	tglx
Thread (19 messages) 19 messages, 7 authors, last reply 2019-11-15
Keyboard shortcuts
hback out one level
jnext message in thread / next series-diff position
kprevious message in thread / previous series-diff position
ldrill in
Escclose help / fold thread tree
?toggle this help