[LinuxPPS] 8 Oct 07:12 - [IPv6]: Fix ICMPv6 redirect handling with target multicast address

[linuxpps: Brian Haley <>]

[IPv6]: Fix ICMPv6 redirect handling with target multicast address  
  
When the ICMPv6 Target address is multicast, Linux processes the  
redirect instead of dropping it. The problem is in this code in  
ndisc_redirect_rcv():  
  
if (ipv6_addr_equal(dest, target)) {  
on_link = 1;  
} else if (!(ipv6_addr_type(target) & IPV6_ADDR_LINKLOCAL)) {  
ND_PRINTK2(KERN_WARNING  
"ICMPv6 Redirect: target address is not  
link-local.\n");  
return;  
}  
  
This second check will succeed if the Target address is, for example,  
FF02::1 because it has link-local scope. Instead, it should be checking  
if it's a unicast link-local address, as stated in RFC 2461/4861 Section  
8.1:  
  
- The ICMP Target Address is either a link-local address (when  
redirected to a router) or the same as the ICMP Destination  
Address (when redirected to the on-link destination).  
  
I know this doesn't explicitly say unicast link-local address, but it's  
implied.  
  
This bug is preventing Linux kernels from achieving IPv6 Logo Phase II  
certification because of a recent error that was found in the TAHI test  
suite - Neighbor Disovery suite test 206 (v6LC.2.3.6_G) had the  
multicast address in the Destination field instead of Target field, so  
we were passing the test. This won't be the case anymore.  
  
The patch below fixes this problem, and also fixes ndisc_send_redirect()  
to not send an invalid redirect with a multicast address in the Target  
field. I re-ran the TAHI Neighbor Discovery section to make sure Linux  
passes all 245 tests now.  
  
Signed-off-by: Brian Haley   
Acked-by: David L Stevens   
Signed-off-by: David S. Miller   
  
net/ipv6/ndisc.c

URL: http://gitweb.enneenne.com/?p=linuxpps;a=commit;h=bf0b48dfc368c07c42b5a3a5658c8ee81b4283ac