Re: [PATCH 4/5] hw/i2c: pmbus: block uninitialised string reads

[Corey Minyard <minyard@acm.org>]

On Wed, Mar 22, 2023 at 05:55:12PM +0000, Titus Rwantare wrote:
> Devices models calling pmbus_send_string can't be relied upon to
> send a non-zero pointer. This logs an error and doesn't segfault.

Yes, a good idea.

Acked-by: Corey Minyard <cminyard@mvista.com>

> 
> Reviewed-by: Patrick Venture <venture@google.com>
> Signed-off-by: Titus Rwantare <titusr@google.com>
> ---
>  hw/i2c/pmbus_device.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/hw/i2c/pmbus_device.c b/hw/i2c/pmbus_device.c
> index bb42e410b4..18e629eaac 100644
> --- a/hw/i2c/pmbus_device.c
> +++ b/hw/i2c/pmbus_device.c
> @@ -94,6 +94,13 @@ void pmbus_send64(PMBusDevice *pmdev, uint64_t data)
>  
>  void pmbus_send_string(PMBusDevice *pmdev, const char *data)
>  {
> +    if (!data) {
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "%s: %s: uninitialised read from 0x%02x\n",
> +                      __func__, DEVICE(pmdev)->canonical_path, pmdev->code);
> +        return;
> +    }
> +
>      size_t len = strlen(data);
>      g_assert(len + pmdev->out_buf_len < SMBUS_DATA_MAX_LEN);
>      pmdev->out_buf[len + pmdev->out_buf_len] = len;
> -- 
> 2.40.0.rc1.284.g88254d51c5-goog
>