4.19-stable review patch. If anyone has any objections, please let me know.
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From: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp
commit 99d3bf5f7377d42f8be60a6b9cb60fb0be34dceb upstream.
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@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=0122fa359a69694395d5 Suggested-by: Dmitry Torokhov dmitry.torokhov@gmail.com Signed-off-by: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Cc: George Kennedy george.kennedy@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/input/input-mt.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/drivers/input/input-mt.c +++ b/drivers/input/input-mt.c @@ -48,6 +48,9 @@ int input_mt_init_slots(struct input_dev 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)