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Re: [Qemu-devel] [PATCH v1] lsi53c895a: check message length value is va
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] [PATCH v1] lsi53c895a: check message length value is valid |
Date: |
Fri, 26 Oct 2018 21:55:01 +0100 |
On 26 October 2018 at 20:43, P J P <address@hidden> wrote:
> From: Prasad J Pandit <address@hidden>
>
> While writing a message in 'lsi_do_msgin', message length value
> in 'msg_len' could be invalid. Add check to avoid OOB access issue.
>
> Signed-off-by: Prasad J Pandit <address@hidden>
> ---
> hw/scsi/lsi53c895a.c | 15 ++++++++++++++-
> 1 file changed, 14 insertions(+), 1 deletion(-)
>
> Update v1: add .post_load routine and an assert() call
> -> https://lists.gnu.org/archive/html/qemu-devel/2018-10/msg05730.html
>
> diff --git a/hw/scsi/lsi53c895a.c b/hw/scsi/lsi53c895a.c
> index d1e6534311..3a40e62853 100644
> --- a/hw/scsi/lsi53c895a.c
> +++ b/hw/scsi/lsi53c895a.c
> @@ -861,12 +861,13 @@ static void lsi_do_status(LSIState *s)
>
> static void lsi_do_msgin(LSIState *s)
> {
> - int len;
> + uint8_t len;
> trace_lsi_do_msgin(s->dbc, s->msg_len);
> s->sfbr = s->msg[0];
> len = s->msg_len;
> if (len > s->dbc)
> len = s->dbc;
> + assert(len <= LSI_MAX_MSGIN_LEN);
> pci_dma_write(PCI_DEVICE(s), s->dnad, s->msg, len);
> /* Linux drivers rely on the last byte being in the SIDL. */
> s->sidl = s->msg[len - 1];
Is it possible to get here with len == 0 ?
thanks
-- PMM