Building a Mesh Network in Rural Somaliland

Re:Building a Mesh Network in Rural Somaliland by voltagex_ on Friday January 03, 2014 @12:11AM (#7004273)

From your screenshot, I don't think that squashfs detection is right, you may have to play around with dd and unsquashfs.

Also try a newer version of binwalk [-1] and/or the 2.0 branch [0]

-1: https://github.com/devttys0/binwalk/

0: https://github.com/devttys0/binwalk/tree/binwalk-2.0

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Re:Building a Mesh Network in Rural Somaliland by hawkinsw on Friday January 03, 2014 @02:13PM (#7007402)

Here are some of the steps that I use to unsquash the binary Commotion images to make changes:

1. Find the PARTs

2. Extract them

3. unsquash: unsquashfs -d image/ squashfs.bin

4. Make the changes.

5. squash: ~/code/commotion-openwrt/commotion-openwrt/openwrt/staging_dir/host/bin/mksquashfs4 image/ squashfs-made.bin -nopad -noappend -root-owned -comp xz -Xpreset 9 -Xe -Xlc 0 -Xlp 2 -Xpb 2 -b 256k

6. pad: ~/code/commotion-openwrt/commotion-openwrt/openwrt/staging_dir/host/bin/padjffs2 squashfs-made.bin 64

7. mkfwimage: ~/code/commotion-openwrt/commotion-openwrt/openwrt/staging_dir/host/bin/mkfwimage -B XM -k kernel.img -r squashfs-made.bin -v XM.ar7240.v6.0.0-OpenWrt-r36682 -o openwrt-ar71xx-generic-ubnt-nano-m-squashfs-factory-DR2-tn.bin

If you are modifying a sysugrade image: Extract 0-1048576 (bytes): that's the kernel Extract the rest: that's the squashfs

Put them back together with ( dd if=vmlinux bs=1048576 conv=sync; dd if=squashfs-made.bin ) > openwrt-ar71xx-generic-ubnt-bullet-m-squashfs-sysupgrade-DR2-custom.bin

These are just my notes. Feel free to contact me if you want more information.

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Re:Building a Mesh Network in Rural Somaliland by cinquemb on Friday January 03, 2014 @12:36AM (#7004329)

I saw your comment yesterday, which made me want to take a stab at it. Thanks alot!

I used dd to get squashfs filesystem by itself[i], and unsquashfs [unsquashfs -v unsquashfs version 4.2 (2011/02/28)][i^2] but that gave that error, then I tried compiling with lzma,xz, lzo by their selfs and neither worked. But your right about the old version of binwalk, I was using v1.2.1.

[i] http://i.imgur.com/Vk35XL0.png

[i^2] http://i.imgur.com/HxTE0rR.png

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Re:Building a Mesh Network in Rural Somaliland by voltagex_ on Friday January 03, 2014 @01:43AM (#7004462)

You're at the point where I normally get stuck. From the slides yesterday, see if you can find the version of squashfs that was used when the firmware was built.

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Re:Building a Mesh Network in Rural Somaliland by cinquemb on Friday January 03, 2014 @02:25AM (#7004527)

That makes sense, cant access linksys website now to check (glad I got this binary in time :P) binwalk says "Squashfs filesystem, little endian, version 3.0" so I'm going to dl that and try again. Who knows, if I can get this to work, I can make a new wifi cracking script[0] that wont take hours with the vulns found so far by going through the backdoor, for security research purposes of course ;)

[0] https://github.com/cinquemb/WifiBruteCrack/blob/master/wifi_...

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Re:Building a Mesh Network in Rural Somaliland by voltagex_ on Friday January 03, 2014 @02:33AM (#7004548)

You may also want to send a request for GPL'd sources to Linksys for this device.

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Re:Building a Mesh Network in Rural Somaliland by voltagex_ on Friday January 03, 2014 @02:51AM (#7004577)

I have another way to extract this for you - can you please contact me?

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