BIND DNS server reports wrong memory size when run in chroot environment

md303 · 10-23-2017, 09:35 PM

Hello,

I have BIND 9.11.2 (built from source) running on Debian Jessie. When I run it in normal context (without chroot) and reload the config, it shows the following line in the log:

Code:

config: info: 'max-cache-size 90%' - setting to 218MB (out of 242MB)

But when I run it in chroot, it shows below:

Code:

config: info: none:103: 'max-cache-size 90%' - setting to 175921860444MB (out of 17592186044415MB)

I am assuming I am missing some files under chroot directory, but I am not sure what. I copied all BIND files/folders, localtime file, null and random dev files, and all library files needed by named process (determined with ldd command) under the chroot directory.

Could anyone assist me in determining what I may be missing?

Any help would be appreciated.

Thank you.

bathory · 10-25-2017, 06:54 AM

Quote:

I am assuming I am missing some files under chroot directory, but I am not sure what. I copied all BIND files/folders, localtime file, null and random dev files, and all library files needed by named process (determined with ldd command) under the chroot directory.

I can't tell if that's the case, but nul and random are not ordinary files.
They are special character files, so you need to use mknod to create them (see 2.4 here)

Code:

mknod /chroot/named/dev/null c 1 3
mknod /chroot/named/dev/random c 1 8
chmod 666 /chroot/named/dev/{null,random}

You can suppress this message by adding something like the following in named.conf:

Code:

max-cache-size 218M;