Re: [PATCH] hw/net/rocker: Avoid undefined shifts with more than 31 ports

[Peter Maydell]

Ping?

thanks
-- PMM

On Fri, 29 Jul 2022 at 16:59, Peter Maydell <peter.maydell@linaro.org> wrote:
>
> In rocker_port_phys_link_status() and rocker_port_phys_enable_read()
> we construct a 64-bit value with one bit per front-panel port.
> However we accidentally do the shift as 32-bit arithmetic, which
> means that if there are more than 31 front-panel ports this is
> undefined behaviour.
>
> Fix the problem by ensuring we use 64-bit arithmetic for the whole
> calculation. (We won't ever shift off the 64-bit value because
> ROCKER_FP_PORTS_MAX is 62.)
>
> Resolves: Coverity CID 1487121, 1487160
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  hw/net/rocker/rocker.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/hw/net/rocker/rocker.c b/hw/net/rocker/rocker.c
> index 31f2340fb91..d8f3f16fe87 100644
> --- a/hw/net/rocker/rocker.c
> +++ b/hw/net/rocker/rocker.c
> @@ -1010,7 +1010,7 @@ static uint64_t rocker_port_phys_link_status(Rocker *r)
>          FpPort *port = r->fp_port[i];
>
>          if (fp_port_get_link_up(port)) {
> -            status |= 1 << (i + 1);
> +            status |= 1ULL << (i + 1);
>          }
>      }
>      return status;
> @@ -1025,7 +1025,7 @@ static uint64_t rocker_port_phys_enable_read(Rocker *r)
>          FpPort *port = r->fp_port[i];
>
>          if (fp_port_enabled(port)) {
> -            ret |= 1 << (i + 1);
> +            ret |= 1ULL << (i + 1);
>          }
>      }
>      return ret;