app-cm-nightlies update

A lot have been downloading my simple cyanogenmod changelog application, it was deployed to market in about 2 days when someone sends an email asking if i could add x device to the list.

Given the nature of cm-nightlies.appspot.com i couldn't pull the device list directly from the site and had to hardcode and distribute a static list of devices with the application, later i discovered that the whole site's source code was available at github. Nice, i just added the functionality my self.

tonky pulled my merge request and i just updated the application to automatically refresh devices as they are added by the cyanogenmod community, Cool :)

Get your curiosity satisfied with cyanogenmod changelog

Wanting to learn about the Actionbar and compatibility with older versions of android, i've made a simple changelog viewing app for cyanogenmod.

The motivation is pretty simple: Finding my self perioticly refreshing the cm-nightlies.appspot.com page looking for exciting changes - i thought it could be cool to have this in my pocket :)

Its available in Google Play (former Android market) and the source code is available at github.

P.S. I'll be happy to receive a pull request with a nice launcher icon - i'm not that into graphics :)

Monitor your dropbox folder changes with GeekTool and PHP

I daily use Dropbox to share files with my friends and customers and with a lot of folders shared it can become quite distracting to have growl popping up every 2 seconds.

On the other hand its often nice see what people are actually doing with your files, and with the excellent GeekTool for OSX its posible to embed this information on your desktop, like this:

The script is written in php which i think is available on the Mac out of the box (I certainly dont remember installing it my self).

The script is available here - you need to edit the file and put your dropbox event feed in the $feedUrl variable and your ready to go :)

Make the Android Emulator ready for SSL MITM

Then investigating native android apps communication, you'll sometimes need to perform a man-in-the-middle attack on the apps, even though they communicate through SSL. Tools like Charles Webproxy makes this pretty easy.

However Charles "dummy" certificate need to be added to your android instance's cacerts.bks in order to make android apps trust the proxy. If you dont do this, you'll end up with https connection's telling you the certificate cant be trusted. e.g.:

But its actually more problematic then this security warning. If your just looking at the browsers SSL trafic, you'll properly be fine with just clicking Continue, but meny native apps won't communicate with the internet if it can't trust the certificate.

Note: This should work with other proxy/sniffing tools as well, just find their certificate and add that instead.

The good news is this is easily done, you need to perform these steps:

1. Make sure your android instance's sdcard partition is large enough to hold the entire /system (its ~100M) 200M will do.
2. Pull out the cacerts.bks file
3. Add the certificate to it
4. Push it back
5. Make it persistent (so it works when the instance reboots)

Note: You'll need to start the emulator with the `emulator` tool found in the android sdk, appending `-partition-size 128` to it, else you cant write to the /system partition, even though remounting it read-write.

So lets walk through the steps

SDcard partition size
This is done in AVD Manager. Open it through Eclipse or by typing

android avd

In your terminal. Dont forget to start the emulator from the commandline with the -partition-size parameter mentioned above. Something like

emulator -avd lille21 -partition-size 128

 Where lille21 is the name of the instance.

Pull out the cacerts.bks file
This is done by issuing adb's pull command

adb pull /system/etc/security/cacerts.bks cacerts.bks

Add your certificate to cacerts.bks
This is done using keytool with the following command

keytool -keystore cacerts.bks -storetype BKS -provider org.bouncycastle.jce.provider.BouncyCastleProvider -storepass changeit -importcert -trustcacerts -alias somealias -file charles-proxy-ssl-proxying-certificate.crt -noprompt

The above command should output something like:

Certificate was added to keystore

Note: On the Mac, you'll maybe get an error about keytool not being able to find bouncycastle, fix this by getting the lastest provider from here and put it in your $JAVA_HOME/jre/lib/ext/. (On the Mac with Lion, thats `/System/Library/Frameworks/JavaVM.framework/Home/lib/ext/`.

Another Note: The charles-proxy-ssl-proxying-certificate.crt is found inside the Charles.app package, e.g `Charles.app/Contents/docs/charles-proxy-ssl-proxying-certificate.crt`.

Third Note: I dont know why the password is changeit, around the internets some have reported it to be "" e.g. nothing.

Push the cacerts.bks file back
First, remount the /system read-write.

adb remount

Second, change the original file's permissions.

adb shell chmod 777 /system/etc/security/cacerts.bks 

Third, push the new cacerts.bks.

adb push cacerts.bks /system/etc/security/

Now the file is in place, but you need to reboot the android instance in order to make it read your new file. (And if you reboot it now, you'll loose your new file, you need to make a new system.img file.

Make it persistent (with a new system.img file)
This is done with a tool called, `mkfs.yaffs2.arm`. Download it here.

 Push the mkfs.yaffs2.arm tool to your android instance.

adb push Downloads/mkfs.yaffs2.arm /data/data/temp/mkfs.yaffs2

Make it executable.

adb shell chmod 777 /data/data/temp/mkfs.yaffs2 

Make a new system.img on the sdcard partition

Jump into the shell with:

adb shell

Inside the shell type:

/data/data/temp/mkfs.yaffs2 /system /sdcard/system.img 

Note: Be sure about the sdcard mount location, on android 2.1 its /sdcard while on android 2.3 its /mnt/sdcard. Check it with the mount command inside the shell

It should output something like this:
mkfs.yaffs2: Android YAFFS2 Tool,Build by PowerGUI
            at http://www.openhandsetalliance.org.cn
Building...
Build Ok.

Quit the shell and download the newly generated system.img.

 adb pull /sdcard/system.img system.img

Note: Again, watch the sdcard's location!

Kill the emulator and boot the new system.img.

Just kill it or exit it in whatever way you see fit, when its closed, you can put your new system.img inside the instances folder.

On the mac its by default ~/.android/avd/<avdname>.avd/ . This is properly also true for linux boxes.

cp system.img .android/avd/lille21.avd/

As far as i know you wont be overwriting anything, the emulator normaly loads a system wide "/system" partition found in your sdk directory, but then it finds the instance has its one, it will load that instead.

Note: My instance is called lille21, you've properly called yours something else.

Now your all ready and set
Boot your instance with

emulator -avd lille21 -http-proxy http://yourinterfaceip:8888

And your ready to monitor all kinds of trafic from webpages and even native android applications!

If your using Charles webproxy remember to enable SSL Proxying.

Ta da! No more certificate trust issues:

Final Note
Ive tried this on android 2.1 and 2.3, not sure if it works on honeycomb (3.0+).
Let me know if you find anything interesting when looking at your favorite app communication :)