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Re: [PATCH 4/4] net/colo.c: fix segmentation fault when packet is not pa
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address@hidden |
Subject: |
Re: [PATCH 4/4] net/colo.c: fix segmentation fault when packet is not parsed correctly |
Date: |
Mon, 21 Mar 2022 03:39:50 +0000 |
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On 09/03/2022 16:38, Zhang Chen wrote:
> When COLO use only one vnet_hdr_support parameter between
> filter-redirector and filter-mirror(or colo-compare), COLO will crash
> with segmentation fault. Back track as follow:
>
> Thread 1 "qemu-system-x86" received signal SIGSEGV, Segmentation fault.
> 0x0000555555cb200b in eth_get_l2_hdr_length (p=0x0)
> at /home/tao/project/COLO/colo-qemu/include/net/eth.h:296
> 296 uint16_t proto = be16_to_cpu(PKT_GET_ETH_HDR(p)->h_proto);
> (gdb) bt
> 0 0x0000555555cb200b in eth_get_l2_hdr_length (p=0x0)
> at /home/tao/project/COLO/colo-qemu/include/net/eth.h:296
> 1 0x0000555555cb22b4 in parse_packet_early (pkt=0x555556a44840) at
> net/colo.c:49
> 2 0x0000555555cb2b91 in is_tcp_packet (pkt=0x555556a44840) at
> net/filter-rewriter.c:63
>
> So wrong vnet_hdr_len will cause pkt->data become NULL.
Not sure if we can check this earlier, well
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
> Add check to
> raise error and add trace-events to track vnet_hdr_len.
>
> Signed-off-by: Tao Xu <tao3.xu@intel.com>
> Signed-off-by: Zhang Chen <chen.zhang@intel.com>
> ---
> net/colo.c | 9 ++++++++-
> net/trace-events | 1 +
> 2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/net/colo.c b/net/colo.c
> index 694f3c93ef..6b0ff562ad 100644
> --- a/net/colo.c
> +++ b/net/colo.c
> @@ -46,7 +46,14 @@ int parse_packet_early(Packet *pkt)
> static const uint8_t vlan[] = {0x81, 0x00};
> uint8_t *data = pkt->data + pkt->vnet_hdr_len;
> uint16_t l3_proto;
> - ssize_t l2hdr_len = eth_get_l2_hdr_length(data);
> + ssize_t l2hdr_len;
> +
> + if (data == NULL) {
> + trace_colo_proxy_main_vnet_info("This packet is not parsed
> correctly, "
> + "pkt->vnet_hdr_len",
> pkt->vnet_hdr_len);
> + return 1;
> + }
> + l2hdr_len = eth_get_l2_hdr_length(data);
>
> if (pkt->size < ETH_HLEN + pkt->vnet_hdr_len) {
> trace_colo_proxy_main("pkt->size < ETH_HLEN");
> diff --git a/net/trace-events b/net/trace-events
> index d7a17256cc..6af927b4b9 100644
> --- a/net/trace-events
> +++ b/net/trace-events
> @@ -9,6 +9,7 @@ vhost_user_event(const char *chr, int event) "chr: %s got
> event: %d"
>
> # colo.c
> colo_proxy_main(const char *chr) ": %s"
> +colo_proxy_main_vnet_info(const char *sta, int size) ": %s = %d"
>
> # colo-compare.c
> colo_compare_main(const char *chr) ": %s"