From d2a69d49f156c0bc3f3ba9f9cb14c21d817eadb3 Mon Sep 17 00:00:00 2001

From: Andrei Borzenkov <arvidjaar@gmail.com>

Date: Sun, 17 May 2015 22:38:30 +0300

Subject: [PATCH 245/261] bootp: ignore gateway_ip (relay) field.

From RFC1542:

   The 'giaddr' field is rather poorly named.  It exists to facilitate

   the transfer of BOOTREQUEST messages from a client, through BOOTP

   relay agents, to servers on different networks than the client.

   Similarly, it facilitates the delivery of BOOTREPLY messages from the

   servers, through BOOTP relay agents, back to the client.  In no case

   does it represent a general IP router to be used by the client.  A

   BOOTP client MUST set the 'giaddr' field to zero (0.0.0.0) in all

   BOOTREQUEST messages it generates.

   A BOOTP client MUST NOT interpret the 'giaddr' field of a BOOTREPLY

   message to be the IP address of an IP router.  A BOOTP client SHOULD

   completely ignore the contents of the 'giaddr' field in BOOTREPLY

   messages.

Leave code ifdef'd out for the time being in case we see regression.

Suggested by: Rink Springer <rink@rink.nu>

Closes: 43396

---

 docs/grub.texi        | 6 ++++--

 grub-core/net/bootp.c | 7 +++++++

 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/docs/grub.texi b/docs/grub.texi

index ef09c8324..98138e04d 100644

--- a/docs/grub.texi

+++ b/docs/grub.texi

@@ -5211,8 +5211,10 @@ by @var{shortname} which can be used to remove it (@pxref{net_del_route}).

 Perform configuration of @var{card} using DHCP protocol. If no card name

 is specified, try to configure all existing cards. If configuration was

 successful, interface with name @var{card}@samp{:dhcp} and configured

-address is added to @var{card}. If server provided gateway information in

-DHCP ACK packet, it is added as route entry with the name @var{card}@samp{:dhcp:gw}. Additionally the following DHCP options are recognized and processed:

+address is added to @var{card}.

+@comment If server provided gateway information in

+@comment DHCP ACK packet, it is added as route entry with the name @var{card}@samp{:dhcp:gw}.

+Additionally the following DHCP options are recognized and processed:

 @table @samp

 @item 1 (Subnet Mask)

diff --git a/grub-core/net/bootp.c b/grub-core/net/bootp.c

index b4b8159cd..62d602d96 100644

--- a/grub-core/net/bootp.c

+++ b/grub-core/net/bootp.c

@@ -237,6 +237,12 @@ grub_net_configure_by_dhcp_ack (const char *name,

   hwaddr.type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET;

   inter = grub_net_add_addr (name, card, &addr, &hwaddr, flags);

+#if 0

+  /* This is likely based on misunderstanding. gateway_ip refers to

+     address of BOOTP relay and should not be used after BOOTP transaction

+     is complete.

+     See RFC1542, 3.4 Interpretation of the 'giaddr' field

+   */

   if (bp->gateway_ip)

     {

       grub_net_network_level_netaddress_t target;

@@ -258,6 +264,7 @@ grub_net_configure_by_dhcp_ack (const char *name,

       target.ipv4.masksize = 32;

       grub_net_add_route (name, target, inter);

     }

+#endif

   if (size > OFFSET_OF (boot_file, bp))

     grub_env_set_net_property (name, "boot_file", bp->boot_file,

-- 

2.13.5