asksven

ApplySettings

sven — 2010-03-06T11:40:14+01:00

ApplySettings

Apply settings is an application interfacing android with the underlying kernel. it allows you to define commands (e.g. 'echo sumthin > somewhere' and execute those from within Android. If there is a file to display a status the command can be added a status information that will be read from that file.

The current version as well as the sources and changelog can be found here and on SlideMe

android

photography:gallery:sidebar

sven — 2010-02-28T12:30:48+01:00

Galleries

computing:legacy:sidebar

sven — 2010-02-28T12:16:57+01:00

Running dropbear on Android

sven — 2010-02-14T00:57:35+01:00

Running dropbear on Android

Telnet is lame so we will have a look at setting up dropbear as sshd on Android. This how-to will show you how to install configure and run dropbear as sshd and how to connect with a ssh client.

Prerequisites

This obviously requires you to have full rights (root) on your Android.
busybox is required as well

Building dropbear

A dropbear built from the original sources won't run properly on Android; the reason is that Android has no proper user support (/etc/passwd). There are two solutions for getting the proper changes to the sources:

check out the changed sources from e.g. http://github.com/cyanogen/android_external_dropbear/
get the original sources and apply the patch yourself. The patch can be found here: http://wiki.androidx86.org/index.php?title=Installing_Dropbear

Once the sources are fixed you now need to crosscompile them. This requires a cross compiler to be setup (this process is not covered here).

The cross compilation and build goes like this:

   ./configure --host=arm-none-linux-gnueabi --disable-zlib
   make CC=arm-none-linux-gnueabi-gcc

Once built the output is following 3 binaries:

dropbear: the sshd
dropbearkey: the keygen
dropbearconvert: a key converter between dropbear and openssh key format

Installing

The installation is quite simple: copy the binaries to your favorite dir to android, e.g. /sdcard

Setup

Server

First we need a server key. Keys are generated using dropbearkey. To generate a RSA server key:

  dropbearkey -t rsa -f dropbear_rsa_host_key

Now create a dir /data/dropbear and copy dropbear_rsa_host_key there.

Test dropbear:

/sdcard/dropbear -r dropbear_rsa_host_key -F -E -v -s

This should show you the debuglog of dropbear starting in non-daemon mode (-F).

Now we need to generate a key/pair for the client to connect with (theoretically the client can connect using password but as stated above there is no read user/password support in Android and we don't want to use any hardcoded passwords (that's the reason why we run dropbear with the option -s (no-password).

To generate a key-pair we do:

  dropbearkey -t rsa -f /sdcard/id_rsa
  dropbearkey -f /sdcard/id_rsa -y > /sdcard/id_rsa.pub

This first command generates a private key, the second step extracts the public-key.

Now we jst need to create /data/dropbear/.ssh and cat the public-key to authorized_keys:

  mkdir /data/dropbear/.ssh
  cat /sdcard/id_rsa.pub > /data/dropbear/.ssh/authorized_keys

now check the perms of /data/dropbear/.ssh and /data/dropbear/.ssh/authorized_keys and make sure they are only readable/writable by root.

Client

Now it's time to take care of the client. As dropbear and openssh use different key formats we first need to convert id_rsa (private key) to openssh-format:

  /sdcard/dropbearconvert dropbear openssh /sdcard/id_rsa /sdcard/id_rsa_openssh

Now move /sdcard/id_rsa and /sdcard/id_rsa_openssh to your desktop (e.g. to your home). We move them instead of copying them as leaving a private key on the phone may compromise it.

Finally connect to the phone:

  ssh -i id_rsa_openssh <phone-ip>

If the connection fails check the Troubleshooting section.

That's it!

Troubleshooting

As stated before both the client and the server are quite sensitive to the sensitive files having the right perms. You can use -vv for both the client and the server to see debug info and fix whatever is wrong.

Common errors are:

.ssh, authorized_keys or your private key have wrong perms
the sshd does not find the public sig. of the key you use to connect with in authorized_keys
there is a mismatch in the key formats between the client (openssh) and the server (dropbear)
a missing /etc/shells file with the path to your shell (e.g. /system/bin/sh) will prevent dropbear from opening a session

Download

Download binaries

android

LedEffects

sven — 2010-02-13T00:09:05+01:00

LedEffects

LedEffects is an Android application specifically designed for XDAndroid or any other Android distro running on linux-msm.

It runs as a service and applies configurable light effects in response to various events like incoming call, SMS, Mail.

For now LedEffects is in development. The current version as well as the changelog can be found here

android

Android projects

sven — 2010-02-12T23:57:48+01:00

Android projects

LedEffects

Legacy projects

These are a few open source projects I've been working on.

CryptLIBOpenPGP

CryptLIBOpenPGP is a collection of Pascal routines and classes that implement the OpenPGP packets. It compiles and has been tested (and will be maintained) for Delphi.

This library is freely available with source code. It can be freely used and distributed conformingly to the terms of the General Public Licence (GPL). Version 1.0

Version 1.0 implements packets types 1, 2, 9, 13. Basically these packets were ncessary to implement sfoPGP, an OpenPGP packet analyser.

CryptLIB

Crypt_LIB is a collection of Pascal routines that implement cryptography. It compiles and has been tested (and will be maintained) both for Delphi and GPC.

This library is freely available with source code. It can be freely used and distributed conformingly to the terms of the General Public Licence (GPL). Version 2.0.1

A fix was made to MD5 for compiance with the RFC Version 2.0

Version 2.0 implements Blowfish and Blowfish CBC with random init. vector, ElGamal, ISAAC (RNG) and LargeIntegers (library for large integer artihmetics)

SChatBUDDY 3.0

SChatBUDDY is an application based on Crypt_LIB. It provides a user interface to crypt text and clipboard support to transfer text from/to a Chat program like ICQ or IRC.

SChatBUDDY supports public key encryption (ElGamal) so there is no need for transfering cleartext sesion keys.

SChatBUDDY is freely available as source code or compiled application. It can be freely used and distributed conformingly to the terms of the General Public Licence (GPL).

Sniffer for OpenPGP (SfOPGP)

sfoPGP is now available with source code