Re: [PATCH v2] esp: process the result of scsi_device_find()

[Philippe Mathieu-Daudé]

Cc'ing Mark.

On 29/12/23 16:26, Alexandra Diupina wrote:
> Add a 'current_lun' check for a null value
> to avoid null pointer dereferencing and
> recover host if NULL return
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: 4eb8606560 (esp: store lun coming from the MESSAGE OUT phase)
> Signed-off-by: Alexandra Diupina <adiupina@astralinux.ru>
> ---
> v2: duplicate the scsi_device_find() logic from esp_select()
>   hw/scsi/esp.c | 10 ++++++++++
>   1 file changed, 10 insertions(+)
>
> diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c
> index 9b11d8c573..03fdd53de6 100644
> --- a/hw/scsi/esp.c
> +++ b/hw/scsi/esp.c
> @@ -292,6 +292,16 @@ static void do_command_phase(ESPState *s)
>       esp_fifo_pop_buf(&s->cmdfifo, buf, cmdlen);
>   
>       current_lun = scsi_device_find(&s->bus, 0, s->current_dev->id, s->lun);
> +
> +    if (!current_lun) {
> +        /* No such drive */
> +        s->rregs[ESP_RSTAT] = 0;
> +        s->rregs[ESP_RINTR] = INTR_DC;
> +        s->rregs[ESP_RSEQ] = SEQ_0;
> +        esp_raise_irq(s);
> +        return;
> +    }
> +
>       s->current_req = scsi_req_new(current_lun, 0, s->lun, buf, cmdlen, s);
>       datalen = scsi_req_enqueue(s->current_req);
>       s->ti_size = datalen;