[klibc] [PATCH 0/1] ipconfig DHCP bug

[Patrick Masotta]

Hi guys 

ipconfig performs not well conformed DHCP client transactions.
This bug does not affect 100% of the DHCP servers as some of 

them are more forgiving than others when considering client 

side protocol mistakes;

i.e When PXE installing on a VMware Workstation using the VMware DHCP 

server plus a proxyDHCP the bug is not present.

When PXE installing on a real PC with a Netgear ISP router as DHCP server

and a proxyDHCP the bug is present.


This is an old bug reported here:
https://bugs.launchpad.net/ubuntu/+source/klibc/+bug/1327412and recently ""partially"" fixed in 

debian/patches/broadcast_dhcp_send.patch found here:

https://launchpad.net/ubuntu/+archive/primary/+files/klibc_2.0.4-8ubuntu1.debian.tar.xz

It would be nice if it is correctly fixed upstream.
as this bug affects lot of distros.

Basically the function dhcp_send() at dhcp_proto.c
mistakenly define 

bootp.yiaddr = dev->ip_addr;
when in a client originated DHCP DHCPREQUEST(RFC2131 Page 36) 

it should be
bootp.yiaddr = INADDR_ANY; // "0"


and also it forgets to define the flags
bootp.flags = htons(0x800);



Best,
Patrick

Signed-off-by: Patrick Masotta <masottaus at yahoo.com>
---

diff -uprN a/klibc-2.0.4/usr/kinit/ipconfig/dhcp_proto.c b/klibc-2.0.4/usr/kinit/ipconfig/dhcp_proto.c
--- a/klibc-2.0.4/usr/kinit/ipconfig/dhcp_proto.c       2014-07-09 09:21:02.000000000 -0600
+++ b/klibc-2.0.4/usr/kinit/ipconfig/dhcp_proto.c       2016-03-21 01:51:12.747420454 -0600
@@ -201,7 +201,8 @@ static int dhcp_send(struct netdev *dev,
bootp.hlen      = dev->hwlen;
bootp.xid       = dev->bootp.xid;
bootp.ciaddr    = INADDR_ANY;
-       bootp.yiaddr    = dev->ip_addr;
+       bootp.yiaddr    = INADDR_ANY;
+       bootp.flags     = htons(0x800);
bootp.giaddr    = INADDR_ANY;
bootp.secs      = htons(time(NULL) - dev->open_time);
memcpy(bootp.chaddr, dev->hwaddr, 16);