From c2cedc78984a4d977bde6a65184525cb9874a38c Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Wed, 15 Jul 2015 18:17:00 +0100 Subject: [PATCH] rtl8139: skip offload on short Ethernet/IP header 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) { Signed-off-by: Stefan Hajnoczi Signed-off-by: Stefano Stabellini --- hw/net/rtl8139.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c index 61a7f7529..81d26e546 100644 --- a/hw/net/rtl8139.c +++ b/hw/net/rtl8139.c @@ -2161,6 +2161,11 @@ 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; -- 2.39.5