[CentOS] problems with CentOS chroot

Maxim Soldatov

makc at makc.name
Mon Dec 17 14:47:28 UTC 2007


Hello,

I've got strange problem with centos (as well as rhel btw) chrooted
environment.

First of all I created simple directory with only the libs for 'bash'
and 'id' tools:

----
# chroot testcase/
bash-3.1# id
uid=0 gid=0 groups=0,1,2,3,4,6,10
----

Yes, I even do not have /etc/ directory inside testcase/ , but id shows
groups from the _host_ root account.


I tried to create full chroot with all the libs and tools based on
debian testing, but the same result:

# id
uid=0 gid=0 groups=0,1,2,3,4,6,10

but if I do 
# ls /etc/shadow /etc/passwd /etc/group
/etc/group  /etc/passwd  /etc/shadow

then
# id
uid=0(root) gid=0(root)
groups=0(root),1(daemon),2(bin),3(sys),4(adm),6(disk),10(uucp)

Args, quite strange for me.

I tried to use strace to identify where is the problem, and only one
thing I found is 530 error on read() :
[cut]
open("/etc/group", O_RDONLY|0x80000)    = -530
getgroups32(0, NULL)                    = 7
getgroups32(7, [0, 1, 2, 3, 4, 6, 10])  = 7
open("/etc/group", O_RDONLY|0x80000)    = -530
open("/etc/group", O_RDONLY|0x80000)    = -530
open("/etc/group", O_RDONLY|0x80000)    = -530
open("/etc/group", O_RDONLY|0x80000)    = -530
open("/etc/group", O_RDONLY|0x80000)    = -530
open("/etc/group", O_RDONLY|0x80000)    = -530
open("/etc/group", O_RDONLY|0x80000)    = -530
write(1, "uid=0 gid=0 groups=0,1,2,3,4,6,1"..., 34) = 34
[cut]


530 is EIOCBRETRY according to errno.h, but, honestly, I do not know
what does it mean and what I can do with it.

SElinux - disabled via /etc/selinux/config.

CentOS release 4.4 (Final) с ядром 2.6.9-67.ELsmp. 
as well as 
Red Hat Enterprise Linux Server release 5.1 (Tikanga) 2.6.18-53.1.4.el5

Could anyone please explain what is going on and what have I done wrong?

Thanks a lot for your time and sorry for my english.

-- 
Maxim Soldatov



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