POC code to trigger UAF in sco_sock_sendmsg().

The example executable is built upon VHCI driver, you can easily transport it to ptty+UART like old POCs (https://www.openwall.com/lists/oss-security/2021/06/08/2).

- Makefile: try with `make vhci`
- poc.c: the main POC code, it will attack a controller, fake a SCO connection on it and then trigger the race
- syzkaller_utils.c/syzkaller_utils.h: helper code (from syzkaller) to interact with VHCI
