Input: uinput - fix crash when mixing old and new init style

If user tries to initialize uinput device mixing old and new style
initialization (i.e. using old UI_SET_ABSBIT instead of UI_ABS_SETUP,
we forget to allocate input->absinfo and will crash when trying to send
absolute events:

        ioctl(ui, UI_DEV_SETUP, &us);
        ioctl(ui, UI_SET_PHYS, "Test");

        ioctl(ui, UI_SET_EVBIT, EV_ABS);
        ioctl(ui, UI_SET_ABSBIT, ABS_X);
        ioctl(ui, UI_SET_ABSBIT, ABS_Y);
        ioctl(ui, UI_DEV_CREATE, 0);

Reported-by: Rodrigo Rivas Costa <rodrigorivascosta@gmail.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=191811
Fixes: fbae10db0940 ("Input: uinput - rework ABS validation")
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c
index 92595b98e7ede7b96dc4c9dd44f4629262f6e3a6..022be0e22eba97b10b95e653f48cee44f1d4ba36 100644 (file)
--- a/drivers/input/misc/uinput.c
+++ b/drivers/input/misc/uinput.c
@@ -263,13 +263,21 @@ static int uinput_create_device(struct uinput_device *udev)
                return -EINVAL;
        }
 
-       if (test_bit(ABS_MT_SLOT, dev->absbit)) {
-               nslot = input_abs_get_max(dev, ABS_MT_SLOT) + 1;
-               error = input_mt_init_slots(dev, nslot, 0);
-               if (error)
+       if (test_bit(EV_ABS, dev->evbit)) {
+               input_alloc_absinfo(dev);
+               if (!dev->absinfo) {
+                       error = -EINVAL;
                        goto fail1;
-       } else if (test_bit(ABS_MT_POSITION_X, dev->absbit)) {
-               input_set_events_per_packet(dev, 60);
+               }
+
+               if (test_bit(ABS_MT_SLOT, dev->absbit)) {
+                       nslot = input_abs_get_max(dev, ABS_MT_SLOT) + 1;
+                       error = input_mt_init_slots(dev, nslot, 0);
+                       if (error)
+                               goto fail1;
+               } else if (test_bit(ABS_MT_POSITION_X, dev->absbit)) {
+                       input_set_events_per_packet(dev, 60);
+               }
        }
 
        if (test_bit(EV_FF, dev->evbit) && !udev->ff_effects_max) {