From cf2e819b7059f199075b099260983e8108eea74a Mon Sep 17 00:00:00 2001 From: Paulo Flabiano Smorigo Date: Wed, 5 Feb 2014 09:42:42 -0200 Subject: [PATCH 133/143] 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 d62d0cc..77581f4 100644 --- a/grub-core/net/arp.c +++ b/grub-core/net/arp.c @@ -162,6 +162,12 @@ grub_net_arp_receive (struct grub_net_buff *nb, if (grub_net_addr_cmp (&inf->address, &target_addr) == 0 && grub_be_to_cpu16 (arp_header->op) == 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; /* We've already checked that pln is either 4 or 16. */ char tmp[16]; -- 1.9.3