Archive for January 2012 | Monthly archive page
If you are interested in developing software (apps, tweaks) for a jailbroken iOS device, then check out my presentation on Developing For Jailbroken iOS platform that I gave at a recent CocoaHeads meeting. This should be a good starting point. The presentation discusses the pros and cons of developing for a jailbroken phone, the various development tools (XCode, Theos) and frameworks (Mobile Substrate) that are available for building applications / run-time patches as well as other relevant information on jailbroken phones (SHSH blobs, jailbreak software etc).
I own an Apple Developer's License and build Apple certified apps for the App Store. I pursue this as a hobby. So hopefully the presentation will get you started.
If you are developing for/on a jailbroken iPhone or iPad you are more than likely going to have to SSH into your iDevice a number of times. This includes transferring files to/from the device via SCP. Entering a password every time you have to SSH into the device is very tedious. Moreover, this becomes imperative if you need automation scripts to SSH/SCP into the device
This post explains how you can enable public-key authentication with SSH in order to bypass the password entry process. Note that enabling password-less entry into your iDevice is a potential security risk because anyone with access to your system can now access/control your device without any authentication. So if you enable this, be sure to secure access to your systems!
The steps to enable public-key authentication with the iPhone/iPad are no different than with any UNIX system.
The following commands need to be executed on the system from which you would be SSHing into your iPhone/iPad.
If you are using a Mac or a Linux system, the commands are executed from the terminal window. If you are using a Windows PC, you would have to run these commands within Cygwin.
- Go to the .ssh folder
MyMacBook-Pro-2:~.mactester$ cd ~/.ssh
- Generate public/private key-pair by running the ssh-keygen command. You will be prompted for some information. You can leave the file to save the key as default. Enter a passphrase . You will be prompted for the passphrase when you try to access your key.
MyMacBook-Pro-2:.ssh mactester$ ssh-keygen -t dsa
Generating public/private dsa key pair.
Enter file in which to save the key (/Users/mactester/.ssh/id_dsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /Users/mactester/.ssh/id_dsa.
Your public key has been saved in /Users/mactester/.ssh/id_dsa.pub.
- A public/private key pair would have been generated in the .ssh folder. The .pub file corresponds to the public key.
MyMacBook-Pro-2:.ssh mactester$ ls
Copy the PUBLIC KEY over to the ~/.ssh folder of your iPhone/iPad (in this example, the IPAddress of my device is 192.168.1.10)
MyMacBook-Pro-2:.ssh mactester$ scp id_dsa.pub firstname.lastname@example.org:~/.ssh
The following commands need to be executed on your iPhone/iPad.
For this, you can SSH into the iDevice (You would still be prompted for a password at this stage) or you can type in the following commands directly in the terminal application window of your jailbroken iDevice
- Save the public key as “authorized_keys”. If you already have public keys associated with other systems stored on your device, be sure to append the public key to “authorized_keys2” as shown in the example below. Make sure you set the right access permissions on the key.
MyiPhone:~root# cd ~/.ssh
MyiPhone:~/.ssh root# cat id_dsa.pub >> authorized_keys2
MyiPhone:~/.ssh root#chmod 0600 authorized_keys2
That’s it. The next time you SSH into your iDevice, you will not be prompted for a password.