segfault when adding OSPF virtual link on Bird 1.6.4

[Cybertinus]

Hello Ondrej,

Thanks for the quick response and patch! I just applied it on a stock 
1.6.4 source, compiled it on my CentOS 7.6 testmachines (with 
./configure --prefix=/ --enable-debug; make; make install) and loaded my 
config with it.
My console/logfile is now being flooded with messages like:
bird: ospf1: Bad DBDES packet from nbr 2.2.2.2 on enp0s8 - MS-bit 
mismatch (7)
bird: ospf1: Bad DBDES packet from nbr 2.2.2.2 on enp0s8 - DD sequence 
number mismatch (4281812757)
bird: ospf1: Bad DBDES packet from nbr 2.2.2.2 on enp0s8 - DD sequence 
number mismatch (4177508748)
bird: ospf1: Bad DBDES packet from nbr 2.2.2.2 on enp0s8 - MS-bit 
mismatch (7)
bird: ospf1: Bad DBDES packet from nbr 2.2.2.2 on enp0s8 - too late for 
DD exchange (7)

But I suspect that this is because I have something wrong in my Bird 
config (it is a test network for a reason off course ;) ).

Will this patch be included in a 1.6.5 release? And do you know when 
such a version will be available?
Does 2.0.x have the same problem and can this patch fix the issue there 
too?

Kind regards,
Cybertinus

On 2018-12-10 02:04, Ondrej Zajicek wrote:
> On Sat, Dec 08, 2018 at 09:48:52PM +0100, Cybertinus wrote:
>> Hello everybody,
>> 
>> Today I was experimenting with a Bird setup. All the Bird machines are
>> CentOS 7.6 VMs running in Virtualbox on my laptop. When I add an OSPF
>> virtual link to hook up two area 0's together I get a segfault of Bird 
>> 1.6.4
>> itself. All the links between the VMs are defined as "Internal 
>> Network"
>> links. Each connection between routers got it's own internal network, 
>> so
>> there should be no overlap between those connections.
> 
> Hello
> 
> Thanks for the thorough bugreport, the attached patch should fix the 
> issue.
> 
>> Steps to reproduce:
>> 1. Create a bird.conf with the following contents specified in the 
>> attached
>> bird.conf
>> 2. Start Bird
>> 3. Add the following line to the area 1 config:
>>        virtual link 2.2.2.2;
>> 4. Run `birdc configure`
>> 5. Observe the following error in your syslog:
>> Dec  8 21:01:35 r3 kernel: bird[3469]: segfault at 32 ip 
>> 0000000000429fe0 sp
>> 00007fff599d3350 error 4 in bird[400000+73
> 
> Technically it would crash during reconfiguration when vlink is already
> defined, even if the reconfiguration changes nothing.