P J P <ppandit@redhat.com> 于2020年3月25日周三 上午1:31写道：

> From: Prasad J Pandit <pjp@fedoraproject.org>
>
> Tulip network driver while copying tx/rx buffers does not check
> frame size against r/w data length. This may lead to OOB buffer
> access. Add check to avoid it.
>
> Limit iterations over descriptors to avoid potential infinite
> loop issue in tulip_xmit_list_update.
>
> Reported-by: Li Qiang <pangpei.lq@antfin.com>
> Reported-by: Ziming Zhang <ezrakiez@gmail.com>
> Reported-by: Jason Wang <jasowang@redhat.com>
> Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
>


Tested-by: Li Qiang <liq3ea@gmail.com>
Reviewed-by: Li Qiang <liq3ea@gmail.com>

Thanks,
Li Qiang



> ---
>  hw/net/tulip.c | 36 +++++++++++++++++++++++++++---------
>  1 file changed, 27 insertions(+), 9 deletions(-)
>
> Update v7: fix length check expression to replace '>=' with '>'
>   -> https://lists.gnu.org/archive/html/qemu-devel/2020-03/msg07160.html
>
> diff --git a/hw/net/tulip.c b/hw/net/tulip.c
> index cfac2719d3..1295f51d07 100644
> --- a/hw/net/tulip.c
> +++ b/hw/net/tulip.c
> @@ -170,6 +170,10 @@ static void tulip_copy_rx_bytes(TULIPState *s, struct
> tulip_descriptor *desc)
>          } else {
>              len = s->rx_frame_len;
>          }
> +
> +        if (s->rx_frame_len + len > sizeof(s->rx_frame)) {
> +            return;
> +        }
>          pci_dma_write(&s->dev, desc->buf_addr1, s->rx_frame +
>              (s->rx_frame_size - s->rx_frame_len), len);
>          s->rx_frame_len -= len;
> @@ -181,6 +185,10 @@ static void tulip_copy_rx_bytes(TULIPState *s, struct
> tulip_descriptor *desc)
>          } else {
>              len = s->rx_frame_len;
>          }
> +
> +        if (s->rx_frame_len + len > sizeof(s->rx_frame)) {
> +            return;
> +        }
>          pci_dma_write(&s->dev, desc->buf_addr2, s->rx_frame +
>              (s->rx_frame_size - s->rx_frame_len), len);
>          s->rx_frame_len -= len;
> @@ -227,7 +235,8 @@ static ssize_t tulip_receive(TULIPState *s, const
> uint8_t *buf, size_t size)
>
>      trace_tulip_receive(buf, size);
>
> -    if (size < 14 || size > 2048 || s->rx_frame_len ||
> tulip_rx_stopped(s)) {
> +    if (size < 14 || size > sizeof(s->rx_frame) - 4
> +        || s->rx_frame_len || tulip_rx_stopped(s)) {
>          return 0;
>      }
>
> @@ -275,7 +284,6 @@ static ssize_t tulip_receive_nc(NetClientState *nc,
>      return tulip_receive(qemu_get_nic_opaque(nc), buf, size);
>  }
>
> -
>  static NetClientInfo net_tulip_info = {
>      .type = NET_CLIENT_DRIVER_NIC,
>      .size = sizeof(NICState),
> @@ -558,7 +566,7 @@ static void tulip_tx(TULIPState *s, struct
> tulip_descriptor *desc)
>          if ((s->csr[6] >> CSR6_OM_SHIFT) & CSR6_OM_MASK) {
>              /* Internal or external Loopback */
>              tulip_receive(s, s->tx_frame, s->tx_frame_len);
> -        } else {
> +        } else if (s->tx_frame_len <= sizeof(s->tx_frame)) {
>              qemu_send_packet(qemu_get_queue(s->nic),
>                  s->tx_frame, s->tx_frame_len);
>          }
> @@ -570,23 +578,31 @@ static void tulip_tx(TULIPState *s, struct
> tulip_descriptor *desc)
>      }
>  }
>
> -static void tulip_copy_tx_buffers(TULIPState *s, struct tulip_descriptor
> *desc)
> +static int tulip_copy_tx_buffers(TULIPState *s, struct tulip_descriptor
> *desc)
>  {
>      int len1 = (desc->control >> TDES1_BUF1_SIZE_SHIFT) &
> TDES1_BUF1_SIZE_MASK;
>      int len2 = (desc->control >> TDES1_BUF2_SIZE_SHIFT) &
> TDES1_BUF2_SIZE_MASK;
>
> +    if (s->tx_frame_len + len1 > sizeof(s->tx_frame)) {
> +        return -1;
> +    }
>      if (len1) {
>          pci_dma_read(&s->dev, desc->buf_addr1,
>              s->tx_frame + s->tx_frame_len, len1);
>          s->tx_frame_len += len1;
>      }
>
> +    if (s->tx_frame_len + len2 > sizeof(s->tx_frame)) {
> +        return -1;
> +    }
>      if (len2) {
>          pci_dma_read(&s->dev, desc->buf_addr2,
>              s->tx_frame + s->tx_frame_len, len2);
>          s->tx_frame_len += len2;
>      }
>      desc->status = (len1 + len2) ? 0 : 0x7fffffff;
> +
> +    return 0;
>  }
>
>  static void tulip_setup_filter_addr(TULIPState *s, uint8_t *buf, int n)
> @@ -651,13 +667,15 @@ static uint32_t tulip_ts(TULIPState *s)
>
>  static void tulip_xmit_list_update(TULIPState *s)
>  {
> +#define TULIP_DESC_MAX 128
> +    uint8_t i = 0;
>      struct tulip_descriptor desc;
>
>      if (tulip_ts(s) != CSR5_TS_SUSPENDED) {
>          return;
>      }
>
> -    for (;;) {
> +    for (i = 0; i < TULIP_DESC_MAX; i++) {
>          tulip_desc_read(s, s->current_tx_desc, &desc);
>          tulip_dump_tx_descriptor(s, &desc);
>
> @@ -675,10 +693,10 @@ static void tulip_xmit_list_update(TULIPState *s)
>                  s->tx_frame_len = 0;
>              }
>
> -            tulip_copy_tx_buffers(s, &desc);
> -
> -            if (desc.control & TDES1_LS) {
> -                tulip_tx(s, &desc);
> +            if (!tulip_copy_tx_buffers(s, &desc)) {
> +                if (desc.control & TDES1_LS) {
> +                    tulip_tx(s, &desc);
> +                }
>              }
>          }
>          tulip_desc_write(s, s->current_tx_desc, &desc);
> --
> 2.25.1
>
>
>