From 305025fe1852b99fcd84b6cd75ed7392d4f49efc Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Fri, 31 Jul 2015 15:59:44 +0200 Subject: [PATCH 3/7] rtl8139: skip offload on short Ethernet/IP header (CVE-2015-5165) Message-id: <1438358388-10575-4-git-send-email-stefanha@redhat.com> Patchwork-id: 67237 O-Subject: [RHEL-7.1.z qemu-kvm EMBARGOED PATCH 3/7] rtl8139: skip offload on short Ethernet/IP header (CVE-2015-5165) Bugzilla: 1248764 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: Miroslav Rezanina --- hw/net/rtl8139.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c index ab32714..409029d 100644 --- a/hw/net/rtl8139.c +++ b/hw/net/rtl8139.c @@ -2142,6 +2142,11 @@ 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; -- 1.8.3.1