Why is my root login disabled? (and why is my filesystem read-only?)

[paperwhite]

I've been trying to SSH into my new Kindle Paperwhite 2015, which was jailbroken using knc1's great tutorial I found here. After jailbreaking, I updated my firmware to 5.8.1 and installed KUAL and USBNet for 5.X, along some other KUAL extensions, and tried to SSH into my Kindle.

But I didn't have the passwords for root. I tried the default passwords, the Kindle password generators (including KindleTool), and none of them worked. So I resorted to kterm to dump /etc/passwd and /etc/shadow, so I could brute-force it with Jack the Ripper.

Turns out, my /etc/passwd looks like this:

root:x:0:0:root:/tmp/root:/bin/sh
daemon:x:1:1:daemon:/usr/sbin:/bin/sh
bin:x:2:2:bin:/bin:/bin/sh
sys:x:3:3:sys:/dev:/bin/sh
sync:x:4:100:sync:/bin:/bin/sync
operator:x:37:37:Operator:/var:/bin/sh
sshd:x:103:99:Operator:/var:/bin/sh
messagebus:x:92:92:messagebus:/bin/false
nobody:x:99:99:nobody:/tmp:/bin/sh
default:x:1000:1000:Default non-root user:/dev/null:/bin/sh
framework:x:9000:150:Framework User:/tmp/framework:/bin/sh
guestuser:x:1002:1001:Guest user:/tmp/guestuser:/bin/sh

And my /etc/shadow looks like this:

root:!:10933:0:99999:7:::
daemon:*:10933:0:99999:7:::
bin:*:10933:0:99999:7:::
sys:*:10933:0:99999:7:::
sync:*:10933:0:99999:7:::
operator:*:10933:0:99999:7:::
sshd:*:10933:0:99999:7:::
messagebus:*:10933:0:99999:7:::
nobody:*:10933:0:99999:7:::
default:!:10933:0:99999:7:::
framework:!:14033:0:99999:7:::
guestuser:!:16506:0:99999:7:::

Every password for every account, including framework, was disabled! That's why I couldn't login!

I didn't want to touch things I don't know anything about, so I thought the easiest thing to do was to use kterm to add a new user:

[kterm]# su
[root]# adduser toor
adduser: /etc/passwd: Read-only file system
[root]#

That didn't work.

I just want to be able to login to my Kindle as root. Can somebody shed some light on why my logins are all messed up, or how to properly fix it?

[geekmaster]

You need to do 'mntroot rw' to remount root as writable. New kindles disable the root account. You need to remove 'x' from accounts in /etc/passwd to enable them (i.e. 'root::'). Be sure to set a password for newly enabled accounts. Then do 'mntroot ro' to remount root as read-only.

(There may be additional details, but that is how I remember it).

[paperwhite]

That was a quick response! mntroot rw did the trick, thank you!

[knc1]

Originally Posted by paperwhite

- - - -
I didn't want to touch things I don't know anything about, so I thought the easiest thing to do was to use kterm to add a new user:

[kterm]# su
[root]# adduser toor
adduser: /etc/passwd: Read-only file system
[root]#

That didn't work.
- - - -

You are contradicting yourself above.
First you state your desire to not touch things you don't know about -
And then present a set of commands that does exactly that.

- - - - -

I suspect you have been speed-reading the documentation that came with USBnetworking (which includes the sshd server).

I.E: use telnet over USB cable

[NiLuJe]

Yeah, double-check the doc, and then set up shared key auth like a good citizen .

Because tweaking passwd might do the job right now, but it's ugly, and will be useless the next time you update your device.

(And unless you already played with the config, the fact that the account is locked is irrelevant, everything is patched to let you in over USB in the default setup).