DSM-G600, DNS-3xx and NSA-220 Hack Forum

Hi,

did you find any more info on where the DNS calls chmod -R 777? I'd like to install funplug on a USB stick as well.

The bootlog suggests that the rootfs is a ramdisk. If that is true, you can exchange chmod by a script which logs it commandline, and its PPID, and the commandline of the parent, and the PPPID, and...
This might tell where and how it's called.

A work around to be able to put FFP on an USB stick could be the usage of a loop device on a big file on the stick.

KyleK wrote:

If a binary tool uses a syscall, the script won't help.

Well, at least then you know it's not a script which does the ugly work.

Ok, I did some digging.

First attempt was to intercept any calls to "chmod" to see who's actually doing the chmodding:

CALLER: 0 init         --->     1 /ffp/bin/bash /bin/chmod 777 -R /mnt/USB/HD_c1

That's not much help

But, I think I still found the culprit: /usr/local/modules/scripts/usbmount (shell-script) calls /usr/local/modules/sbin/usb_disk (binary). And that binary contains the string "chmod 777 -R 777 %s/%s/%s". Bam!
Now my problem is, since /usr/local/modules is mounted ro, I can neither change the script nor hex-patch the binary.

Any ideas how to obtain this?

Hey guys,

I've been running funplug from a (ext2) USB stick for a couple of weeks now, and finally had some time to create a little package for everyone to use.
I followed Mijzelfs suggestions to replace /bin/chmod with a custom script that blocks that one particular command that causes so much trouble.

You can get the package here: dns325-chmod-fix-0.1-1.tgz

This script should work with ffp-0.5 and ffp-0.7.

So, what does it do?
The package contains 2 script files, chmod_usb.sh and dns325-fix-chmod.sh. The first is the replacement for /bin/chmod, the second does the dirty work to replace /bin/chmod with a symlink to chmod_usb.sh.
All this is done automatically when you install the script (via funpkg -i dns325-chmod-fix-0.1-1.tgz).
The 2 scripts are copied to /usr/local/config. Also, the file rc.init.sh residing in that folder is modified so that it calls dns325-fix-chmod.sh when you boot the NAS.
That script is perfect for the task, because it gets called right before the hotplug script takes action, and also before the NAS looks for fun_plug.


Anyway, let me know how it goes for you (this is my first package with a doinst.sh).

PS: For now, all calls to /bin/chmod are logged to /usr/local/config/chmod.log, and you can see here which calls are suppressed and which go through.


Edit: Fixed link.

Last edited by KyleK (2012-06-13 09:51:40)

Hi KyleK,
your installation package works like a charm. Finally is my USB mounted as it should be - with permissions.

Thank you again!

Gyngy

Depending on your goal you could avoid automounting. When the 345 supports loopdevices, you could let a filesystem start on an offset on a raw disk. It won't be automounted, but fun_plug can mount it.

Updated the link in my post, as the package was moved to a different folder. Thanks for catching this, bazzer!

Hi,

i ran into a problem trying to run FFP on USB.

Followed shadowandy guide on http://www.shadowandy.net/2011/12/movin … to-usb.htm

however following all the steps..

except running into an error on Update it to suppress HD_c instead of HD_c1 by typing “cat /usr/local/config/chmod_usb.sh | sed -e ‘s/\/HD_c1\”/\/HD_c\”/’ >> /usr/local/config/chmod_usb.sh“

can't get it to run hence i forgot it knowing my mounting is hd_c1

followed all the way through..

and finally the error here.

/dev/sdc1: UUID="5ef5ce8f-cab0-4adc-9f54-cc320707d57a" TYPE="ext2"
Success. Found 5ef5ce8f-cab0-4adc-9f54-cc320707d57a.
* FFP was not found on a USB device. Reverting back to HDD-based FFP

KyleK wrote:

Did you format the USB stick and put the fun_plug.tgz archive onto the stick?

yes i did format the stick and did a copy instead.

following shadowandy guide.

Copy the current ffp folder to USB

We will be shifting the current ffp installation on your disk to the USB drive and it will take a while before the copy completes so sit back and enjoy a can of coke or a cup of Starbucks.

Copy the current ffp installation to USB by typing “cp -a /mnt/HD/HD_a2/ffp /mnt/USB/HD_c1/“

I did this.

I have double confirmed that my USB stick is ext2 format and have ffp folder inside.

KyleK wrote:

Is your USB stick mounted to /mnt/USB/HD_c or /mnt/USB/HD_c1?
If the latter, then you need to modify the fun_plug script (put the correct path in the variable FFP_USB, right at the beginning of the file).

oh! i get it. let me try it now!

thank you so much!

I have just installed transmission. Do i need to move the file to the USB instead?