From a666c8bd18aee7bf1b202b6b8c0ffe953bd2c1b6 Mon Sep 17 00:00:00 2001 From: Andrei Borzenkov Date: Sun, 17 May 2015 22:38:30 +0300 Subject: [PATCH] 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 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 4af22aff8..88bd75f38 100644 --- a/docs/grub.texi +++ b/docs/grub.texi @@ -5162,8 +5162,10 @@ 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 613675533..4fdeac3ef 100644 --- a/grub-core/net/bootp.c +++ b/grub-core/net/bootp.c @@ -157,6 +157,12 @@ 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; @@ -178,6 +184,7 @@ 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,