From: Dmitry Torokhov dmitry.torokhov@gmail.com
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
--- drivers/hid/hid-input.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)
--- a/drivers/hid/hid-input.c +++ b/drivers/hid/hid-input.c @@ -1026,9 +1026,15 @@ static void hidinput_configure_usage(str }
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);
@@ -1087,9 +1093,11 @@ mapped: 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)