Edit /system/device_table.txt:

1# See package/makedevs/README for details
2#
3# This device table is used to assign proper ownership and permissions
4# on various files. It doesn't create any device file, as it is used
5# in both static device configurations (where /dev/ is static) and in
6# dynamic configurations (where devtmpfs, mdev or udev are used).
7#
8# <name>        <type>  <mode>  <uid> <gid> <major> <minor> <start> <inc> <count>
9/dev          d 755 0 0 - - - - -
10/tmp          d 1777  0 0 - - - - -
11/etc          d 755 0 0 - - - - -
12/root         d 700 0 0 - - - - -
13/var/www        d 755 33  33  - - - - -
14/etc/shadow       f 600 0 0 - - - - -
15/etc/passwd       f 644 0 0 - - - - -
16/etc/network/if-up.d      d 755 0 0 - - - - -
17/etc/network/if-pre-up.d    d 755 0 0 - - - - -
18/etc/network/if-down.d      d 755 0 0 - - - - -
19/etc/network/if-post-down.d   d 755 0 0 - - - - -
20# uncomment this to allow starting x as non-root
21#/usr/X11R6/bin/Xfbdev          f 4755  0 0 - - - - -
22/home/user        d 777 1000  1000  - - - - -
23/etc/ssh        d 755 0 0 - - - - -
24/etc/ssh/ssh_config     f 600 0 0 - - - - -

Should be intuitive for basic usage