KindleTERM - a SSH client kindlet

vdp · 11-17-2010, 05:15 AM

Hi,

I wrote a quick and dirty hack based on the MidpSSH J2ME SSH/telnet client, to make it run on Kindle. Well, I am somewhat hesitant on the 'quick' part, since it took me a good amount of time during the last 3 weeks, but it is certainly dirty

. You can find the git repo on GitHub.

Thanks to Andrew de Quincey for making possible writing kindlets without the highly restricted Amazon development kit.

I've only had the opportunity to test it on my Kindle DXG, so I don't know how well it performs on other models.

I will describe the installation process in case someone is willing to try it.

The usual disclaimer applies: You should not take the steps described below unless you are comfortable about messing with your device and potentially bricking it. DO IT ON YOUR OWN RISK - if something goes wrong I will probably not be able to help you.

1) Copy the developer.keystore in /var/local/java/keystore directory. I wanted to use the AdQ's keystore used for KIF but unfortunatelly Ant's signjar task fails with message:

Code:

[signjar] jarsigner: Certificate chain not found for: dkadq.  dkadq must reference a valid KeyStore key entry containing a private key and corresponding public key certificate chain.

I am not all that familiar with the Java keystores so I am not sure yet what the problem is.
If someone have an idea how to fix it you are wellcome.

2) The Kindle framework's sandbox should be relaxed somewhat to allow SSH connections.
In /opt/amazon/ebook/security/external.policy after "grant signedBy "Kindlet" {" add the lines

Code:

permission java.net.SocketPermission "localhost:1024-", "accept, connect, listen";
permission java.net.SocketPermission "192.168.2.1", "connect, accept";
permission java.net.SocketPermission "localhost", "connect, accept";

These changes permit connections to the kindlet, and from the kindlet to the localhost and usbnet host ip. Perhaps here is the place to say (as already mentioned by others on this forum) that the Amazon 3G access should be considered privilege rather than right, so I will not support any attempts to exploit the free 3G.

3) Copy the KindleTERM.azw2 to the 'documents' directory.

Known bugs and limitations:

- I am not sure if this is the case if you only make connections to the kindle (localhost), but I discovered that the connections from Kindle to other hosts are automatically disconnected after 2 or so minutes. If you want to prevent this you should stop netwatchd daemon.

Code:

/etc/init.d/netwatchd stop

- MidpSSH tries to emulate a DEC vt320 terminal. It seems that it is not that common type of terminal so neither my Ubuntu 9.04 nor the Kindle have a terminfo description. I tried different terminfo files (e.g. the one from http://www.sunmanagers.org/archives/1995/1561.html) none of them work as it should for example in VIM. Don't know if the reason is the imperfect emulation in terminal.VT320 class, the way I use it in kindle.KindleTerminal or terminfo entries needs tweaking. Every help on this issue is very wellcome.

- Key events handling is far from perfect. For example there is still no way to emulate "TAB" on the device's keyboard. It should be trivial to fix though. I implemented also a "remote keyboard" feature - the kindlet listens to port 3333 for key events. On the host machine you can start:

Code:

java -cp KindleTERM.azw2 kindle.RemoteKeyboard

and the keys you press when it's window is on focus are relayed to the kindlet.
It needs a java property file, named remote_keyboard.properties in the current working directory:

Code:

host 192.168.2.2
port 3333

This feature is a potential security hole if you use it on a WiFi-enabled Kindle, so you should change your firewall accordingly.

- If you choose to save session info it is saved in plain text in the kindlet's 'work' directory so it is a security risk also.

NiLuJe · 11-17-2010, 01:17 PM

Nice!

Here's a bunch of vt320 terminfo files (from the latest ncurses release), maybe one of them will help...

.

vladm · 11-17-2010, 04:35 PM

so just to confirm I understand this right - it runs as app on your kindle and allows you to connect via ssh either to the kindle itself or to a remote host - basically use kindle as ssh terminal / client?

Polvo · 11-18-2010, 04:41 AM

Well done! I managed to install on my Kindle 3 (3G) and connect to localhost.

Elleo · 11-21-2010, 04:05 PM

You can find vt320 terminfo in the ncurses-term package on Debian and Ubuntu, however I found that most ncurses based applications (irssi, mutt, etc.) still don't behave correctly with it.

The simplest solution I've come up with is to set the TERM environment variable to "ansi" instead of "vt320". i.e. run "export TERM=ansi" after logging in.

stormont · 11-22-2010, 01:53 PM

Thank you

stasenko · 12-05-2010, 02:24 PM

I try to connect to kindle with this params:

Code:

host: localhost
port:22
username: root
password: (what value do I need enter to this field?)

connection log is

Code:

Connecting to localhost:22 ...OK
...
...
...
Requesting authentication
Sent password
Sent password
Sent password
Sent password
Sent password
Sent password
Sent password
Sent password
Sent password
Sent password

What is wrong?

stormont · 12-05-2010, 05:16 PM

Quote:

Originally Posted by stasenko

I try to connect to kindle with this params:

Code:

host: localhost
port:22
username: root
password: (what value do I need enter to this field?)

connection log is

Code:

Connecting to localhost:22 ...OK
...
...
...
Requesting authentication
Sent password
Sent password
Sent password
Sent password
Sent password
Sent password
Sent password
Sent password
Sent password
Sent password

What is wrong?

telnet/ssh w/USB ethernet, then at root shell give your kindle a password - type 'passwd'

stasenko · 12-06-2010, 01:19 AM

Quote:

Originally Posted by stormont

telnet/ssh w/USB ethernet, then at root shell give your kindle a password - type 'passwd'

Thank you

ennerr · 12-12-2010, 04:09 AM

Is there mapping for Ctrl key?

Thanks

JDShaffer · 12-12-2010, 06:47 PM

OK. I'm not computer-illiterate, but I am Kindle-hacking illiterate.

How do I get to the point where I can see /var/local/java/keystore on my Kindle 2?

Currently I have the latest "jailbreak" and "screensaver hack" and "font hack" as described by NiLuJe in the Fonts & ScreenSavers hacks for Kindles thread. And I'm running the latest Kindle 2 firmware, 2.5.4.

Not sure how to get root from this point. Sorry if this has been answered somewhere, but I can't seem to locate the answer myself.

Thank you, and cheers.

Jeffrey

JDShaffer · 12-12-2010, 10:38 PM

(Deleted older comment)

OK. I got it all figured out. I read your blog and found the info I needed. I ended up using scp to get your developer key on there... (and later saw you made a .bin file that will do the same. Got your ktest, term, and kif (tested the first two so far).

Great stuff! Thanks for all the hard work!
Now, if I could figure out how to port Abiword or at least Pico (sorry, I'm not used to vi -- my bad).

Cheers,
Jeffrey

JDShaffer · 12-13-2010, 08:16 AM

-----

JDShaffer · 12-13-2010, 08:19 AM

Nevermind. Got it. Had to have usbNetworking running, even if I'm not using the laptop to connect in...

JDShaffer · 12-13-2010, 09:37 AM

@vdp -- VI looks nice full screen, but is there an ESC key built in to the KindleTERM app?

11-17-2010, 05:15 AM	#1
vdp Enthusiast Posts: 45 Karma: 10842 Join Date: Aug 2010 Device: Kindle DXG	KindleTERM - a SSH client kindlet Hi, I wrote a quick and dirty hack based on the MidpSSH J2ME SSH/telnet client, to make it run on Kindle. Well, I am somewhat hesitant on the 'quick' part, since it took me a good amount of time during the last 3 weeks, but it is certainly dirty . You can find the git repo on GitHub. Thanks to Andrew de Quincey for making possible writing kindlets without the highly restricted Amazon development kit. I've only had the opportunity to test it on my Kindle DXG, so I don't know how well it performs on other models. I will describe the installation process in case someone is willing to try it. The usual disclaimer applies: You should not take the steps described below unless you are comfortable about messing with your device and potentially bricking it. DO IT ON YOUR OWN RISK - if something goes wrong I will probably not be able to help you. 1) Copy the developer.keystore in /var/local/java/keystore directory. I wanted to use the AdQ's keystore used for KIF but unfortunatelly Ant's signjar task fails with message: Code: [signjar] jarsigner: Certificate chain not found for: dkadq. dkadq must reference a valid KeyStore key entry containing a private key and corresponding public key certificate chain. I am not all that familiar with the Java keystores so I am not sure yet what the problem is. If someone have an idea how to fix it you are wellcome. 2) The Kindle framework's sandbox should be relaxed somewhat to allow SSH connections. In /opt/amazon/ebook/security/external.policy after "grant signedBy "Kindlet" {" add the lines Code: permission java.net.SocketPermission "localhost:1024-", "accept, connect, listen"; permission java.net.SocketPermission "192.168.2.1", "connect, accept"; permission java.net.SocketPermission "localhost", "connect, accept"; These changes permit connections to the kindlet, and from the kindlet to the localhost and usbnet host ip. Perhaps here is the place to say (as already mentioned by others on this forum) that the Amazon 3G access should be considered privilege rather than right, so I will not support any attempts to exploit the free 3G. 3) Copy the KindleTERM.azw2 to the 'documents' directory. Known bugs and limitations: - I am not sure if this is the case if you only make connections to the kindle (localhost), but I discovered that the connections from Kindle to other hosts are automatically disconnected after 2 or so minutes. If you want to prevent this you should stop netwatchd daemon. Code: /etc/init.d/netwatchd stop - MidpSSH tries to emulate a DEC vt320 terminal. It seems that it is not that common type of terminal so neither my Ubuntu 9.04 nor the Kindle have a terminfo description. I tried different terminfo files (e.g. the one from http://www.sunmanagers.org/archives/1995/1561.html) none of them work as it should for example in VIM. Don't know if the reason is the imperfect emulation in terminal.VT320 class, the way I use it in kindle.KindleTerminal or terminfo entries needs tweaking. Every help on this issue is very wellcome. - Key events handling is far from perfect. For example there is still no way to emulate "TAB" on the device's keyboard. It should be trivial to fix though. I implemented also a "remote keyboard" feature - the kindlet listens to port 3333 for key events. On the host machine you can start: Code: java -cp KindleTERM.azw2 kindle.RemoteKeyboard and the keys you press when it's window is on focus are relayed to the kindlet. It needs a java property file, named remote_keyboard.properties in the current working directory: Code: host 192.168.2.2 port 3333 This feature is a potential security hole if you use it on a WiFi-enabled Kindle, so you should change your firewall accordingly. - If you choose to save session info it is saved in plain text in the kindlet's 'work' directory so it is a security risk also. Last edited by ixtab; 10-09-2013 at 05:02 AM.

11-17-2010, 01:17 PM	#2
NiLuJe BLAM! Posts: 13,477 Karma: 26012492 Join Date: Jun 2010 Location: Paris, France Device: Kindle 2i, 3g, 4, 5w, PW, PW2, PW5; Kobo H2O, Forma, Elipsa, Sage, C2E	Nice! Here's a bunch of vt320 terminfo files (from the latest ncurses release), maybe one of them will help... . Last edited by HarryT; 10-08-2013 at 11:51 AM.

11-22-2010, 01:53 PM	#6
stormont Junior Member Posts: 2 Karma: 10 Join Date: Nov 2010 Device: Kindle 3 Wifi	Thank you Last edited by stormont; 11-25-2010 at 06:53 PM.

12-12-2010, 06:47 PM	#11
JDShaffer Hobbit Posts: 20 Karma: 10 Join Date: Jan 2007 Location: Shizuoka, Japan Device: k2i	Noob Question... OK. I'm not computer-illiterate, but I am Kindle-hacking illiterate. How do I get to the point where I can see /var/local/java/keystore on my Kindle 2? Currently I have the latest "jailbreak" and "screensaver hack" and "font hack" as described by NiLuJe in the Fonts & ScreenSavers hacks for Kindles thread. And I'm running the latest Kindle 2 firmware, 2.5.4. Not sure how to get root from this point. Sorry if this has been answered somewhere, but I can't seem to locate the answer myself. Thank you, and cheers. Jeffrey

12-12-2010, 10:38 PM	#12
JDShaffer Hobbit Posts: 20 Karma: 10 Join Date: Jan 2007 Location: Shizuoka, Japan Device: k2i	(Deleted older comment) OK. I got it all figured out. I read your blog and found the info I needed. I ended up using scp to get your developer key on there... (and later saw you made a .bin file that will do the same. Got your ktest, term, and kif (tested the first two so far). Great stuff! Thanks for all the hard work! Now, if I could figure out how to port Abiword or at least Pico (sorry, I'm not used to vi -- my bad). Cheers, Jeffrey Last edited by JDShaffer; 12-13-2010 at 08:11 AM.

11-17-2010, 04:35 PM	#3
vladm Junior Member Posts: 3 Karma: 10 Join Date: Oct 2010 Device: K3g	so just to confirm I understand this right - it runs as app on your kindle and allows you to connect via ssh either to the kindle itself or to a remote host - basically use kindle as ssh terminal / client?

11-18-2010, 04:41 AM	#4
Polvo Enthusiast Posts: 45 Karma: 14412 Join Date: Oct 2010 Location: Spain Device: Kindle 3 - 3G	Well done! I managed to install on my Kindle 3 (3G) and connect to localhost.

11-21-2010, 04:05 PM	#5
Elleo Junior Member Posts: 5 Karma: 12 Join Date: Nov 2010 Location: Aberystwyth, UK Device: Kindle 3 (3G)	You can find vt320 terminfo in the ncurses-term package on Debian and Ubuntu, however I found that most ncurses based applications (irssi, mutt, etc.) still don't behave correctly with it. The simplest solution I've come up with is to set the TERM environment variable to "ansi" instead of "vt320". i.e. run "export TERM=ansi" after logging in.

12-12-2010, 04:09 AM	#10
ennerr Junior Member Posts: 1 Karma: 10 Join Date: Dec 2010 Device: Kindle 3 Wifi	Is there mapping for Ctrl key? Thanks

12-13-2010, 08:16 AM	#13
JDShaffer Hobbit Posts: 20 Karma: 10 Join Date: Jan 2007 Location: Shizuoka, Japan Device: k2i	----- Last edited by JDShaffer; 12-13-2010 at 09:38 AM. Reason: Removed dumb question

12-13-2010, 08:19 AM	#14
JDShaffer Hobbit Posts: 20 Karma: 10 Join Date: Jan 2007 Location: Shizuoka, Japan Device: k2i	Nevermind. Got it. Had to have usbNetworking running, even if I'm not using the laptop to connect in...

12-13-2010, 09:37 AM	#15
JDShaffer Hobbit Posts: 20 Karma: 10 Join Date: Jan 2007 Location: Shizuoka, Japan Device: k2i	@vdp -- VI looks nice full screen, but is there an ESC key built in to the KindleTERM app?

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