Fix NULL deref segfault in bhyve's usb_mouse.c

Some of the cases inside umouse_request() (usr.sbin/bhyve/usb_mouse.c)
use the data component of an event, while only partially checking if
it's NULL. 'data' has a NULL check, but then 'data' is immediately
deferenced anyway after the check regardless of if it's NULL or not.

For example:
	case UREQ(UR_GET_STATUS, UT_READ_INTERFACE):
	case UREQ(UR_GET_STATUS, UT_READ_ENDPOINT):
		DPRINTF(("umouse: (UR_GET_STATUS, UT_READ_INTERFACE)"));
		if (data != NULL && len > 1) {
			USETW(udata, 0);
			data->blen = len - 2;
			data->bdone += 2;
		}
		eshort = data->blen > 0;
		break;

There are actually four occurrences of this same bug, each in a
different case in this switch block.

Signed-off-by: Jack Bendtsen <jackdbendtsen@gmail.com>
PR: 282237
Reviewed by: imp, jhb, vexeduxr
MFC After: 1 week
Pull Request: https://github.com/freebsd/freebsd-src/pull/1728

0 files changed, 0 insertions, 0 deletions