[Bug 193246] Bug in IPv6 multicast join(), uncovered by Jenkins

[Andrey V. Elsukov]

On 03.09.2014 14:05, bugzilla-noreply at freebsd.org wrote:
> In FreeBSD, in  src/sys/netinet6/in6_mcast.c inside in6p_join_group(), there
> is this:
> 
>         if (!IN6_IS_ADDR_MULTICAST(&gsa->sin6.sin6_addr))
>                 return (EINVAL);
> 
> Since IN6_IS_ADDR_MULTICAST() only checks if the first octet is 0xff, that is
> what is returning the EINVAL.  So the JDK is creating
> an IPV4 multicast address mapped inside an IPV6 address.  The FreeBSD
> kernel code is rejecting this as a valid IPV6 multicast address.
> 
> I'm not sure if it is better to fix this in the kernel or the JDK.

Hi,

you said that this code works in linux. I looked in the linux kernel
source, and I think it should return EINVAL too.
net/ipv6/mcast.c:ipv6_sock_mc_join:

 154         if (!ipv6_addr_is_multicast(addr))
 155                 return -EINVAL;

-- 
WBR, Andrey V. Elsukov