Commit 64c8b76e authored Dec 07, 2019 by Dmitry Torokhov Committed by Greg Kroah-Hartman Jan 14, 2020

HID: hid-input: clear unmapped usages



commit 4f3882177240a1f55e45a3d241d3121341bead78 upstream.

We should not be leaving half-mapped usages with potentially invalid
keycodes, as that may confuse hidinput_find_key() when the key is located
by index, which may end up feeding way too large keycode into the VT
keyboard handler and cause OOB write there:

BUG: KASAN: global-out-of-bounds in clear_bit include/asm-generic/bitops-instrumented.h:56 [inline]
BUG: KASAN: global-out-of-bounds in kbd_keycode drivers/tty/vt/keyboard.c:1411 [inline]
BUG: KASAN: global-out-of-bounds in kbd_event+0xe6b/0x3790 drivers/tty/vt/keyboard.c:1495
Write of size 8 at addr ffffffff89a1b2d8 by task syz-executor108/1722
...
 kbd_keycode drivers/tty/vt/keyboard.c:1411 [inline]
 kbd_event+0xe6b/0x3790 drivers/tty/vt/keyboard.c:1495
 input_to_handler+0x3b6/0x4c0 drivers/input/input.c:118
 input_pass_values.part.0+0x2e3/0x720 drivers/input/input.c:145
 input_pass_values drivers/input/input.c:949 [inline]
 input_set_keycode+0x290/0x320 drivers/input/input.c:954
 evdev_handle_set_keycode_v2+0xc4/0x120 drivers/input/evdev.c:882
 evdev_do_ioctl drivers/input/evdev.c:1150 [inline]

Cc: stable@vger.kernel.org
Reported-by:  <syzbot+19340dff067c2d3835c0@syzkaller.appspotmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Tested-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 2d21f37e

drivers/hid/hid-input.c

+12 −4

Original line number	Diff line number	Diff line
		@@ -1125,9 +1125,15 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel
		}

		mapped:
		if (device->driver->input_mapped && device->driver->input_mapped(device,
		hidinput, field, usage, &bit, &max) < 0)
		goto ignore;
		if (device->driver->input_mapped &&
		device->driver->input_mapped(device, hidinput, field, usage,
		&bit, &max) < 0) {
		/*
		* The driver indicated that no further generic handling
		* of the usage is desired.
		*/
		return;
		}

		set_bit(usage->type, input->evbit);

		@@ -1208,9 +1214,11 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel
		set_bit(MSC_SCAN, input->mscbit);
		}

		ignore:
		return;

		ignore:
		usage->type = 0;
		usage->code = 0;
		}

		void hidinput_hid_event(struct hid_device hid, struct hid_field field, struct hid_usage *usage, __s32 value)