On Wed, Aug 18, 2021 at 7:30 AM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
>
> The original EHCI register struct used a trailing 0-element array for
> addressing the N_PORTS-many available registers. However, after
> commit a46af4ebf9ff ("USB: EHCI: define extension registers like normal ones")
> the 0-element array started to overlap the USBMODE extension register.
>
> To avoid future compile-time warnings about accessing indexes within a
> 0-element array, rearrange the struct to actually describe the expected
> layout (max 15 registers) with a union. All offsets remain the same, and
> bounds checking becomes possible on accesses to port_status and hostpc.
...
> /* HOSTPC: offset 0x84 */
> - u32 hostpc[0]; /* HOSTPC extension */
> + u32 hostpc[HCS_N_PORTS_MAX];
> #define HOSTPC_PHCD (1<<22) /* Phy clock disable */
> #define HOSTPC_PSPD (3<<25) /* Port speed detection */
>
> - u32 reserved5[17];
> + u32 reserved5[2];
Shouldn't it be rather [17 - PORT_MAX]? for accuracy?
Or also a union approach?
--
With Best Regards,
Andy Shevchenko
