coredumps with Bird 3.0.0 with bfd authentication enabled

[Daniel Suchy]

Hello,
with Bird 3.0.0 I'm experiencing crashes during `birdc configure`. 
During quick debugging I figured it's somewhat related to BFD - in my 
use case I have keyed SHA1 authentication enabled (but similar issue I 
had with simple BFD session authentication). With session authentication 
disabled, there's no issue.

With BFD session authentication enabled, first configure call after 
daemon start isn't problem, but second causes seqfault.

I'm using pre-build packages from pkg.labs.nic.cz. Issue observed on 
amd64 and armhf builds.

Also discovered, that I have to fully restart daemon to take 
authentication configuration change in effect (configure doesn't reflect 
the change) - this quite complicated debugging :-)

crash as seen in dmesg:

kernel: bird[1535627]: segfault at 0 ip 00005563d2355893 sp 
00007fbd6e5fc3e8 error 4 in bird[4e893,5563d231b000+100000] likely on 
CPU 2 (core 2, socket 0)
kernel: Code: 1f 84 00 00 00 00 00 31 ff 48 89 f8 c3 66 2e 0f 1f 84 00 
00 00 00 00 f3 0f 1e fa 4c 8b 05 15 14 14 00 48 85 ff 74 36 48 8b 0f 
<48> 8b 01 48 85 c0 75 13 eb 29 0f 1f 00 48 8b 10 48 89 c1 48 85 d2


 From coredump:

                                                       Module libzstd.so.1
                                                       Stack trace of 
thread 1535627:
                                                       #0 
0x00005563d2355893 n/a (n/a + 0x0)
                                                       #1 
0x00005563d2380fe9 n/a (n/a + 0x0)
                                                       #2 
0x00005563d23e9085 n/a (n/a + 0x0)
                                                       #3 
0x00005563d23eaa90 n/a (n/a + 0x0)
                                                       #4 
0x00005563d23ec429 n/a (n/a + 0x0)
                                                       #5 
0x00005563d23475ef n/a (n/a + 0x0)
                                                       #6 
0x00005563d23eb78f n/a (n/a + 0x0)
                                                       #7 
0x00007fbd70749f52 n/a (libc.so.6 + 0x91f52)
                                                       #8 
0x00007fbd707c8678 n/a (libc.so.6 + 0x110678)

                                                       Stack trace of 
thread 1535624:
                                                       #0 
0x00007fbd707bae9f __poll (libc.so.6 + 0x102e9f)
                                                       #1 
0x00005563d23eb82e n/a (n/a + 0x0)
                                                       #2 
0x00007fbd70749f52 n/a (libc.so.6 + 0x91f52)
                                                       #3 
0x00007fbd707c8678 n/a (libc.so.6 + 0x110678)

                                                       Stack trace of 
thread 1535623:
                                                       #0 
0x00007fbd707bae9f __poll (libc.so.6 + 0x102e9f)
                                                       #1 
0x00005563d231e035 n/a (n/a + 0x0)
                                                       #2 
0x00007fbd706e1d68 n/a (libc.so.6 + 0x29d68)
                                                       #3 
0x00007fbd706e1e25 __libc_start_main (libc.so.6 + 0x29e25)
                                                       #4 
0x00005563d231e985 n/a (n/a + 0x0)
                                                       ELF object binary 
architecture: AMD x86-64



- Daniel