ssh on Onyx Boox M92

[peterx]

Hi!

It would be great if we could run an ssh server on the Onyx Boox M92. I managed to compile dropbear statically linked and run it. There are two problems, though:

1. the kernel does not support the devpts filesystem, which is important for ssh login
2. the ssh server crashes very often (always after the first command), I do not know how this is caused, though

I have attached the binary (gzipped due to forum restrictions). You additionally need a host key (use your desktop to generate it) and you have to copy your public user key to /root/.ssh/authorized_keys (do not forget to create the directory).

[FDD]

Originally Posted by peterx

the kernel does not support the devpts filesystem, which is important for ssh login

Hi! I cannot try this myself right now (my M92 is still in China ) but it should be possible to kexec to a new kernel with with devpts support (if kexec is unsupported, it could be compiled as a module). I don't think there are sources for the last kernel on https://github.com/onyx-intl/ , so we should probably ask Onyx to put them online. I have little time right now, but I'd like to give this a try using qemu...

EDIT: The kernel is probably the stock one from Freescale, I'll give it a look.

[peterx]

Originally Posted by FDD

Hi! I cannot try this myself right now (my M92 is still in China ) but it should be possible to kexec to a new kernel with with devpts support (if kexec is unsupported, it could be compiled as a module). I don't think there are sources for the last kernel on https://github.com/onyx-intl/ , so we should probably ask Onyx to put them online. I have little time right now, but I'd like to give this a try using qemu...

EDIT: The kernel is probably the stock one from Freescale, I'll give it a look.

The kernel version is 2.6.35.3-998-ga1cd8a7 which at least seems to be common (there is something on the web about it).

Another thing to try is to use BSD style pseudo-terminals, i.e. create the files /dev/ptyp... and /dev/ttyp...

[FDD]

Good news! I managed to compile and use the serial gadget module, so it is now possibile to connect to the M92.
I'll try to polish the whole thing a bit and upload it in the evening.

[FDD]

Here we go. DISCLAIMER: you are on your own, so be careful.
Also, I tested this only on the original v1.6 firmware, but could (should?) run on the other versions.

Unzip the attached zip file somewhere in your M92 or SD card; you will find two directories, gserial and allow_root.

To login in your M92:

1. plug the usb cable;
2. answer "No" to the USB Connection popup;
3. run start_usb_serial.oar from the gserial directory;
4. your computer should detect a new serial port device. Use you favourite terminal emulator to connect to it.
5. login with user app, no password will be asked. (Be careful, even if you are not root, permission aren't really going to protect you.)

To logout press Control+D or type exit. If you want to login again, re-run the start_usb_serial.oar command.

When you are done, logout then execute stop_usb_serial.oar without disconnecting the USB cable. The usual popup will appear.

So now you want to login as root, don't you?
Go to the allow_root directory and run root_pw_clear.oar; now you can login as root, no password asked. To restore everything as it was, run root_pw_restore.oar (will only work if you don't change the root password by hand, but if you can do that, I assume you can restore everything by yourself.) Also, does anybody knows what the original root password is?

Be careful and have fun!

EDIT: The archive was updated because I put the wrong module in there, as you can read below. Sorry guys!

[pkbo]

Originally Posted by FDD

Here we go.

Did not work for me:

insmod: cannot insert './g_serial.ko': Invalid module format (-1): Exec format error

And in the dmesg

g_serial: no symbol version for module_layout

How to make it work? Thanks.

[peterx]

Originally Posted by pkbo

Did not work for me:

insmod: cannot insert './g_serial.ko': Invalid module format (-1): Exec format error

And in the dmesg

g_serial: no symbol version for module_layout

How to make it work? Thanks.

I am getting the same error. Can we somehow force the kernel to load the module? Why does it work for you, FDD?

[FDD]

Originally Posted by peterx

I am getting the same error. Can we somehow force the kernel to load the module? Why does it work for you, FDD?

Ok, I put the wrong module copy in the archive, I changed the orginal post, it should be fixed now. Give it a try!

[pkbo]

It works fine now.

[peterx]

Originally Posted by FDD

Ok, I put the wrong module copy in the archive, I changed the orginal post, it should be fixed now. Give it a try!

Absolutely great! The USB console is so much faster than ssh over Wifi and, more important: It is absolutely stable. Thanks a lot for that module!

By the way, you can use the program called "cu" to connect to a serial console under linux:

cu -l /dev/ttyACM0 -s 115200

[sergeyvl12]

Originally Posted by FDD

Good news! I managed to compile and use the serial gadget module, so it is now possibile to connect to the M92.
I'll try to polish the whole thing a bit and upload it in the evening.

FDD, thanks!

It runs on my A62. Could you compile g_ether.ko (please!)

P.S. I can't run Qt applications from 'app' user:

Qt for Embedded Linux data directory is not owned by user 16

[sergeyvl12]

Originally Posted by peterx

Hi!

It would be great if we could run an ssh server on the Onyx Boox M92. I managed to compile dropbear statically linked and run it. There are two problems, though:

1. the kernel does not support the devpts filesystem, which is important for ssh login
2. the ssh server crashes very often (always after the first command), I do not know how this is caused, though

Try this. I use it with my Onyx Boox A62. It has never crashed (I used it for a month) and works quite fast.

http://pbsdk.vlasovsoft.net/files/onyx_dropbear.zip

BTW today I managed to turn on wifi without starting a web browser. I'll update this package with wifi scripts soon...

"the kernel does not support the devpts filesystem, which is important for ssh login"

Not so important ... we still can work using ssh -T ...

[rkomar]

Is it definitely the case that the kernel doesn't support devpts? On my Pocketbook device, the kernel supports it, but the OS wasn't set up for it. I got root access and fixed that by changing the permissions on /dev/ptmx and by adding the option gid=5 for devpts in /etc/fstab. Perhaps that's all that is necessary on the Onyx devices, as well.

[sergeyvl12]

Originally Posted by rkomar

Is it definitely the case that the kernel doesn't support devpts? On my Pocketbook device, the kernel supports it, but the OS wasn't set up for it. I got root access and fixed that by changing the permissions on /dev/ptmx and by adding the option gid=5 for devpts in /etc/fstab. Perhaps that's all that is necessary on the Onyx devices, as well.

ssh server (dropbear) on Onyx is started from root user and I login to Onyx as root, so it is not the question of permissions I think...

[peterx]

Originally Posted by rkomar

Is it definitely the case that the kernel doesn't support devpts? On my Pocketbook device, the kernel supports it, but the OS wasn't set up for it. I got root access and fixed that by changing the permissions on /dev/ptmx and by adding the option gid=5 for devpts in /etc/fstab. Perhaps that's all that is necessary on the Onyx devices, as well.

If you want to mount the devpts filesystem, the kernel responds with something like "unknown filesystem type devpts" and devpts is not available as a module.