Re: [Qemu-devel] [PATCH v2] scsi: megasas: check 'read_queue_head' index value

[Alexander Graf <agraf@suse.de>]

On 05/25/2016 02:25 PM, P J P wrote:
> From: Prasad J Pandit <pjp@fedoraproject.org>
>
> While doing MegaRAID SAS controller command frame lookup, routine
> 'megasas_lookup_frame' uses 'read_queue_head' value as an index
> into 'frames[MEGASAS_MAX_FRAMES=2048]' array. Limit its value
> within array bounds to avoid any OOB access.
>
> Reported-by: Li Qiang <liqiang6-s@360.cn>
> Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>

Reviewed-by: Alexander Graf <agraf@suse.de>


Alex

> ---
>   hw/scsi/megasas.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> Update as per
>    -> https://lists.gnu.org/archive/html/qemu-devel/2016-05/msg04403.html
>
> diff --git a/hw/scsi/megasas.c b/hw/scsi/megasas.c
> index bf642d4..cc66d36 100644
> --- a/hw/scsi/megasas.c
> +++ b/hw/scsi/megasas.c
> @@ -650,7 +650,9 @@ static int megasas_init_firmware(MegasasState *s, MegasasCmd *cmd)
>       pa_hi = le32_to_cpu(initq->pi_addr_hi);
>       s->producer_pa = ((uint64_t) pa_hi << 32) | pa_lo;
>       s->reply_queue_head = ldl_le_pci_dma(pcid, s->producer_pa);
> +    s->reply_queue_head %= MEGASAS_MAX_FRAMES;
>       s->reply_queue_tail = ldl_le_pci_dma(pcid, s->consumer_pa);
> +    s->reply_queue_tail %= MEGASAS_MAX_FRAMES;
>       flags = le32_to_cpu(initq->flags);
>       if (flags & MFI_QUEUE_FLAG_CONTEXT64) {
>           s->flags |= MEGASAS_MASK_USE_QUEUE64;