From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> [ Upstream commit 99d3bf5f7377d42f8be60a6b9cb60fb0be34dceb ] syzbot is reporting too large allocation at input_mt_init_slots(), for num_slots is supplied from userspace using ioctl(UI_DEV_CREATE). Since nobody knows possible max slots, this patch chose 1024. Reported-by: syzbot <syzbot+0122fa359a69694395d5@xxxxxxxxxxxxxxxxxxxxxxxxx> Closes: https://syzkaller.appspot.com/bug?extid=0122fa359a69694395d5 Suggested-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/input/input-mt.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/input/input-mt.c b/drivers/input/input-mt.c index 6c7326c93721c..fd01c9306e66c 100644 --- a/drivers/input/input-mt.c +++ b/drivers/input/input-mt.c @@ -48,6 +48,9 @@ int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots, return 0; if (mt) return mt->num_slots != num_slots ? -EINVAL : 0; + /* Arbitrary limit for avoiding too large memory allocation. */ + if (num_slots > 1024) + return -EINVAL; mt = kzalloc(struct_size(mt, slots, num_slots), GFP_KERNEL); if (!mt) -- 2.43.0
