GUF-Yocto-jethro-9.0-r7707-0
i.MX6
User Manual
Udev can be configured in
/etc/udev/udev.conf
.
More information about udev can be found at:
https://www.kernel.org/pub/linux/utils/kernel/hotplug/udev/udev.html
4.1.2 D-Bus
The
dbus
service is a message bus system, a simple way for applications to communicate with each another.
Additionally, D-Bus helps coordinating the process lifecycle: it makes it simple and reliable to code a
single
instance
application or daemon, and to launch applications and daemons on demand when their services are
needed.
Garz & Fricke systems are shipped with dbus bindings for glib and Qt. Therefore, the corresponding APIs can
be used for application programming. Furthermore, Garz & Fricke systems are configured to support
HALD
that
allows to detect hotplugging events in applications asynchronously.
The dbus service has a startup link that points to the corresponding start script:
/etc/rc5.d/S02dbus-1 -> /etc/init.d/dbus-1
More information about dbus can be found at:
http://www.freedesktop.org/wiki/Software/dbus
More information about the Qt dbus bindings can be found at:
http://qt-project.org/doc/qt-4.7/intro-to-dbus.html
More information about the glib dbus bindings can be found at:
http://dbus.freedesktop.org/doc/dbus-glib
4.1.3 SSH service
The
ssh
service allows the user to log in on the target system. Futhermore, the SFTP and SCP functionalities
are activated to allow secure file transfers. The communication is encrypted.
The ssh service has a startup link that points to the corresponding start script:
/etc/rc5.d/S09sshd -> /etc/init.d/openssh
The startup script simply starts
/usr/sbin/sshd
as a daemon. The sshd configuration can be found in the target’s
root file system at
/etc/ssh/sshd_config
.
More information about OpenSSH can be found at:
Login
Garz & Fricke devices are configured to use passwords for authentication also on the ssh service. As
there is no password set for root by default, this is a widely open door for attackers. See the
[
I
chapter how to handle this issue.
SSH Keys
The Garz & Fricke yocto images are containing default SSH Keys that are the same on every image.
Those keys are used to identify the device when connecting to it from a remote host, to make sure you send
your password to the correct device ( and not some Man-in-the-middle ). To make use of this feature you should
generate your own keys with:
root@gufboardll:~# rm /etc/ssh/ssh_host_*key*
root@gufboardll:~# /etc/init.d/sshd restart
generating ssh RSA key...
generating ssh ECDSA key...
generating ssh DSA key...
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