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Re: [Qemu-devel] [PATCH] net/vmxnet3: Refine l2 header validation
From: |
Dmitry Fleytman |
Subject: |
Re: [Qemu-devel] [PATCH] net/vmxnet3: Refine l2 header validation |
Date: |
Wed, 19 Aug 2015 10:31:54 -0700 |
ACK.
> On Aug 18, 2015, at 02:45 AM, Shmulik Ladkani <address@hidden> wrote:
>
> From: Dana Rubin <address@hidden>
>
> Validation of l2 header length assumed minimal packet size as
> eth_header + 2 * vlan_header regardless of the actual protocol.
>
> This caused crash for valid non-IP packets shorter than 22 bytes, as
> 'tx_pkt->packet_type' hasn't been assigned for such packets, and
> 'vmxnet3_on_tx_done_update_stats()' expects it to be properly set.
>
> Refine header length validation in 'vmxnet_tx_pkt_parse_headers'.
> Check its return value during packet processing flow.
>
> As a side effect, in case IPv4 and IPv6 header validation failure,
> corrupt packets will be dropped.
>
> Signed-off-by: Dana Rubin <address@hidden>
> Signed-off-by: Shmulik Ladkani <address@hidden>
> ---
> hw/net/vmxnet3.c | 4 +---
> hw/net/vmxnet_tx_pkt.c | 19 ++++++++++++++++---
> 2 files changed, 17 insertions(+), 6 deletions(-)
>
> diff --git a/hw/net/vmxnet3.c b/hw/net/vmxnet3.c
> index 59b06b8..f37297f 100644
> --- a/hw/net/vmxnet3.c
> +++ b/hw/net/vmxnet3.c
> @@ -729,9 +729,7 @@ static void vmxnet3_process_tx_queue(VMXNET3State *s, int
> qidx)
> }
>
> if (txd.eop) {
> - if (!s->skip_current_tx_pkt) {
> - vmxnet_tx_pkt_parse(s->tx_pkt);
> -
> + if (!s->skip_current_tx_pkt && vmxnet_tx_pkt_parse(s->tx_pkt)) {
> if (s->needs_vlan) {
> vmxnet_tx_pkt_setup_vlan_header(s->tx_pkt, s->tci);
> }
> diff --git a/hw/net/vmxnet_tx_pkt.c b/hw/net/vmxnet_tx_pkt.c
> index f7344c4..eb88ddf 100644
> --- a/hw/net/vmxnet_tx_pkt.c
> +++ b/hw/net/vmxnet_tx_pkt.c
> @@ -142,11 +142,24 @@ static bool vmxnet_tx_pkt_parse_headers(struct
> VmxnetTxPkt *pkt)
>
> bytes_read = iov_to_buf(pkt->raw, pkt->raw_frags, 0, l2_hdr->iov_base,
> ETH_MAX_L2_HDR_LEN);
> - if (bytes_read < ETH_MAX_L2_HDR_LEN) {
> + if (bytes_read < sizeof(struct eth_header)) {
> + l2_hdr->iov_len = 0;
> + return false;
> + }
> +
> + l2_hdr->iov_len = sizeof(struct eth_header);
> + switch (be16_to_cpu(PKT_GET_ETH_HDR(l2_hdr->iov_base)->h_proto)) {
> + case ETH_P_VLAN:
> + l2_hdr->iov_len += sizeof(struct vlan_header);
> + break;
> + case ETH_P_DVLAN:
> + l2_hdr->iov_len += 2 * sizeof(struct vlan_header);
> + break;
> + }
> +
> + if (bytes_read < l2_hdr->iov_len) {
> l2_hdr->iov_len = 0;
> return false;
> - } else {
> - l2_hdr->iov_len = eth_get_l2_hdr_length(l2_hdr->iov_base);
> }
>
> l3_proto = eth_get_l3_proto(l2_hdr->iov_base, l2_hdr->iov_len);
> --
> 1.9.1
>