Input: add safety guards to input_set_keycode()
commit cb222aed03d798fc074be55e59d9a112338ee784 upstream.
If we happen to have a garbage in input device's keycode table with values
too big we'll end up doing clear_bit() with offset way outside of our
bitmaps, damaging other objects within an input device or even outside of
it. Let's add sanity checks to the returned old keycodes.
Reported-by: syzbot+c769968809f9359b07aa@syzkaller.appspotmail.com
Reported-by: syzbot+76f3a30e88d256644c78@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/20191207212757.GA245964@dtor-ws
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/input/input.c b/drivers/input/input.c
index d95c34e..5d94fc3 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -850,16 +850,18 @@
}
}
- __clear_bit(*old_keycode, dev->keybit);
- __set_bit(ke->keycode, dev->keybit);
-
- for (i = 0; i < dev->keycodemax; i++) {
- if (input_fetch_keycode(dev, i) == *old_keycode) {
- __set_bit(*old_keycode, dev->keybit);
- break; /* Setting the bit twice is useless, so break */
+ if (*old_keycode <= KEY_MAX) {
+ __clear_bit(*old_keycode, dev->keybit);
+ for (i = 0; i < dev->keycodemax; i++) {
+ if (input_fetch_keycode(dev, i) == *old_keycode) {
+ __set_bit(*old_keycode, dev->keybit);
+ /* Setting the bit twice is useless, so break */
+ break;
+ }
}
}
+ __set_bit(ke->keycode, dev->keybit);
return 0;
}
@@ -915,9 +917,13 @@
* Simulate keyup event if keycode is not present
* in the keymap anymore
*/
- if (test_bit(EV_KEY, dev->evbit) &&
- !is_event_supported(old_keycode, dev->keybit, KEY_MAX) &&
- __test_and_clear_bit(old_keycode, dev->key)) {
+ if (old_keycode > KEY_MAX) {
+ dev_warn(dev->dev.parent ?: &dev->dev,
+ "%s: got too big old keycode %#x\n",
+ __func__, old_keycode);
+ } else if (test_bit(EV_KEY, dev->evbit) &&
+ !is_event_supported(old_keycode, dev->keybit, KEY_MAX) &&
+ __test_and_clear_bit(old_keycode, dev->key)) {
struct input_value vals[] = {
{ EV_KEY, old_keycode, 0 },
input_value_sync
