From e70ff64e2817dce971fbd79fd65e9b6b2a7ecb39 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Sat, 1 Aug 2015 08:39:29 -0400 Subject: [PATCH 3/7] rtl8139: skip offload on short Ethernet/IP header (CVE-2015-5165) RH-Author: Stefan Hajnoczi Message-id: <1438418373-7324-4-git-send-email-stefanha@redhat.com> Patchwork-id: 67260 O-Subject: [virt-devel] [RHEL-6.7.z qemu-kvm EMBARGOED PATCH 3/7] rtl8139: skip offload on short Ethernet/IP header (CVE-2015-5165) Bugzilla: 1248761 RH-Acked-by: Dr. David Alan Gilbert RH-Acked-by: Xiao Wang RH-Acked-by: Laszlo Ersek 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: Jeff E. Nelson --- hw/rtl8139.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/hw/rtl8139.c b/hw/rtl8139.c index 04cc14b..f4a983b 100644 --- a/hw/rtl8139.c +++ b/hw/rtl8139.c @@ -2146,6 +2146,11 @@ static int rtl8139_cplus_transmit_one(RTL8139State *s) { DEBUG_PRINT(("RTL8139: +++ 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; -- 2.1.0