[PATCH 1/2] aio: handle integer overflow in io_getevents() timespec usage

[Benjamin LaHaise]

Dmitry Vyukov reported an integer overflow in io_getevents() when
running a fuzzer.  Upon investigation, the triggers appears to be that
an invalid value for the tv_sec or tv_nsec was passed in which is not
handled by timespec_to_ktime().  This patch fixes that by making
io_getevents() return -EINVAL when timespec_valid() checks fail.  We
use timespec_valid() instead of timespec_valid_strict() to avoid issues
caused by userspace not knowing the cutoff for KTIME_SEC_MAX.

Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Signed-off-by: Benjamin LaHaise <bcrl@xxxxxxxxx>
Acked-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>

diff --git a/fs/aio.c b/fs/aio.c
index 155f842..e0d5398 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1269,6 +1269,8 @@ static long read_events(struct kioctx *ctx, long min_nr, long nr,
 
 		if (unlikely(copy_from_user(&ts, timeout, sizeof(ts))))
 			return -EFAULT;
+		if (!timespec_valid(&ts))
+			return -EINVAL;
 
 		until = timespec_to_ktime(ts);
 	}
-- 
2.5.0