From 76e51503bb7882da7beb8113177f2e89427813b2 Mon Sep 17 00:00:00 2001 From: Paulo Flabiano Smorigo Date: Wed, 5 Feb 2014 09:42:42 -0200 Subject: [PATCH 17/87] trim arp packets with abnormal size GRUB uses arp request to create the arp response. If the incoming packet is foobared, GRUB needs to trim the arp response packet before sending it. --- grub-core/net/arp.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/grub-core/net/arp.c b/grub-core/net/arp.c index 4b68c41..f7c59d3 100644 --- a/grub-core/net/arp.c +++ b/grub-core/net/arp.c @@ -142,6 +142,12 @@ grub_net_arp_receive (struct grub_net_buff *nb, if (grub_net_addr_cmp (&inf->address, &target_addr) == 0 && arp_packet->op == grub_cpu_to_be16_compile_time (ARP_REQUEST)) { + if ((nb->tail - nb->data) > 50) + { + grub_dprintf ("net", "arp packet with abnormal size (%ld bytes).\n", + nb->tail - nb->data); + nb->tail = nb->data + 50; + } grub_net_link_level_address_t target; struct grub_net_buff nb_reply; struct arppkt *arp_reply; -- 2.5.0