Re: [Qemu-devel] [PATCH v2] net: rocker: fix an incorrect array bounds check

[Jason Wang]

On 12/28/2015 06:54 PM, P J P wrote:
> From: Prasad J Pandit <address@hidden>
>
> While processing transmit(tx) descriptors in 'tx_consume' routine
> the switch emulator suffers from an off-by-one error, if a
> descriptor was to have more than allowed(ROCKER_TX_FRAGS_MAX=16)
> fragments. Fix an incorrect bounds check to avoid it.
>
> Reported-by: Qinghao Tang <address@hidden>
> Signed-off-by: Prasad J Pandit <address@hidden>
> ---
>  hw/net/rocker/rocker.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/hw/net/rocker/rocker.c b/hw/net/rocker/rocker.c
> index c57f1a6..2e77e50 100644
> --- a/hw/net/rocker/rocker.c
> +++ b/hw/net/rocker/rocker.c
> @@ -232,6 +232,9 @@ static int tx_consume(Rocker *r, DescInfo *info)
>          frag_addr = rocker_tlv_get_le64(tlvs[ROCKER_TLV_TX_FRAG_ATTR_ADDR]);
>          frag_len = rocker_tlv_get_le16(tlvs[ROCKER_TLV_TX_FRAG_ATTR_LEN]);
>  
> +        if (iovcnt >= ROCKER_TX_FRAGS_MAX) {
> +            goto err_too_many_frags;
> +        }
>          iov[iovcnt].iov_len = frag_len;
>          iov[iovcnt].iov_base = g_malloc(frag_len);
>          if (!iov[iovcnt].iov_base) {
> @@ -244,10 +247,7 @@ static int tx_consume(Rocker *r, DescInfo *info)
>              err = -ROCKER_ENXIO;
>              goto err_bad_io;
>          }
> -
> -        if (++iovcnt > ROCKER_TX_FRAGS_MAX) {
> -            goto err_too_many_frags;
> -        }
> +        iovcnt++;
>      }
>  
>      if (iovcnt) {

Applied in my -net.

Thanks