Commit e1c120a9 authored by Stefan Hajnoczi's avatar Stefan Hajnoczi
Browse files

rtl8139: skip offload on short Ethernet/IP header (CVE-2015-5165) 



Transmit offload features access Ethernet and IP headers the packet.  If
the packet is too short we must not attempt to access header fields:

  int proto = be16_to_cpu(*(uint16_t *)(saved_buffer + 12));
  ...
  eth_payload_data = saved_buffer + ETH_HLEN;
  ...
  ip = (ip_header*)eth_payload_data;
  if (IP_HEADER_VERSION(ip) != IP_HEADER_VERSION_4) {

Reported-by: default avatar朱东海(启路) <donghai.zdh@alibaba-inc.com>
Reviewed-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent d6812d60

hw/net/rtl8139.c

+5 −0
Original line number Diff line number Diff line
@@ -2150,6 +2150,11 @@ static int rtl8139_cplus_transmit_one(RTL8139State *s) 
        {

            DPRINTF("+++ C+ mode offloaded task checksum\n");



            /* Large enough for Ethernet and IP headers? */

            if (saved_size < ETH_HLEN + sizeof(ip_header)) {

                goto skip_offload;

            }



            /* ip packet header */

            ip_header *ip = NULL;

            int hlen = 0;