Re: [Qemu-devel] [PATCH 2/3] adlib: mark as insecure and deprecated.

[Paolo Bonzini]

On 25/10/2018 10:52, Gerd Hoffmann wrote:
> We have a lovely, guest-triggerable buffer overflow in opl2 emulation.
> 
> Reproducer:
>     outw(0xff60, 0x220);
>     outw(0x1020, 0x220);
>     outw(0xffb0, 0x220);
> Result:
>     Will overflow FM_OPL->AR_TABLE[] (see hw/audio/fmopl.[ch])

I am dumb and I don't understand.  In set_ar_dr you get

        v = 0xff
        ar = 15
        dr = 15

and OPL->AR_TABLE[60] is accessed.  The size of the array is 75, which
seems to be actually 14 more than required.  Likewise OPL->DR_TABLE[60]
is accessed.

The next accesses use SLOT->ksr which is 0 so it's fine too.

Paolo