Unable to open included file even it has permissions?

[Robert Scheck]

Good evening,

could somebody please point out my mistake? Why is BIRD telling that it
can't access /var/lib/foo/bird.conf?

$ birdc configure soft
BIRD 2.0.7 ready.
Reading configuration from /etc/bird.conf
/etc/bird.conf:206:10 Unable to open included file /var/lib/foo/bird.conf: Permission denied
$ 

$ tail /etc/bird.conf
#
# protocol bgp client2 from rr_clients {
#	neighbor 10.0.2.1;
# }
#
# protocol bgp client3 from rr_clients {
#	neighbor 10.0.3.1;
# }

include "/var/lib/foo/bird.conf";  # This is line 206
$

$ ps aux | grep bird
bird     29334  0.0  0.1  43752  2968 ?        Ss   00:50   0:00 /usr/sbin/bird -f -u bird -g bird
root     29531  0.0  0.0 112724   960 pts/0    S+   00:58   0:00 grep --color=auto bird
$  

$ ls -ld /var/lib/foo/ /var/lib/foo/bird.conf 
drwxr-x---. 2 foo  foo  4096 Feb 27 00:53 /var/lib/foo/
-rw-r--r--. 1 root root   10 Feb 27 00:53 /var/lib/foo/bird.conf
$ 

$ id bird
uid=996(bird) gid=993(bird) groups=993(bird),1000(foo)
$ 

$ strace -fff -p 29334 -s 4096
[…]
open("/var/lib/foo/bird.conf", O_RDONLY) = -1 EACCES (Permission denied)
[…] ^C
$ 

But:

$ su - bird -s /bin/bash -c "head /var/lib/foo/bird.conf"
# Include
$ 

And:

$ su - bird -s /bin/bash -c "id"
uid=996(bird) gid=993(bird) groups=993(bird),1000(foo) context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
$ 

Even it's not relevant:
$ getenforce 
Permissive
$ 


Regards,
  Robert