Ask Ubuntu General Room

Nathan Osman

12:31 AM

That moment where your own code becomes so complex you don't understand it.

"Who wrote this flaming pile of... oh wait... it was me."

TheWanderer

lol

have you seen my Java?

Android Dev

12:55 AM

@NathanOsman Yup, I've experienced that moment before...

@NathanOsman - Are you available to test another APK?

Nathan Osman

Sure.

Android Dev

Alright, so I've implemented the extract part, and hopefully you'll be able to extract a file from an image I send you. Give me a sec to get it on google drive

@NathanOsman OK, here's the APK and here's the image

@NathanOsman - If all goes well you should end up with a file called recovered_data.bin on your root storage directory. It should open up in Libreoffice

(By root I mean /mnt/sdcard, not /)

Nathan Osman

04-29 18:05:53.216 11424 11600 I System.out: Reading stego-image from disk...
04-29 18:05:53.216 11424 11600 I System.out: Error!
04-29 18:05:53.217 11424 11600 E AndroidRuntime: FATAL EXCEPTION: Thread-2
04-29 18:05:53.217 11424 11600 E AndroidRuntime: Process: com.androiddev.filesteg, PID: 11424
04-29 18:05:53.217 11424 11600 E AndroidRuntime: java.lang.NullPointerException: Attempt to invoke virtual method 'int android.graphics.Bitmap.getWidth()' on a null object reference
04-29 18:05:53.217 11424 11600 E AndroidRuntime:        at com.androiddev.filesteg.FileSteg2Util.doExtract(FileSteg2…

Unfortunately, it crashes :(

Android Dev

@NathanOsman Yeah, I had that too - make sure you select the image with the first screen that pops up, don't switch to another app to select it. (The different apps provide different URIs)

But as long as I selected it with the first screen that popped up it didn't crash

@NathanOsman - I probably should have told you that up front, sorry

Nathan Osman

1:12 AM

Ah.

Android Dev

Yeah, I'll need to get around to fixing that at some point...

Nathan Osman

I actually have some code that might help you with that.

I ran into the same problem with NitroShare.

Android Dev

Oh, I'd love to have a look at it then :)

Nathan Osman

If memory serves me correctly, it's this block here: github.com/nitroshare/nitroshare-android/blob/master/app/src/…

Android Dev

You might find my choice of a file to embed in that image rather funny - I just needed something long enough that it would take multiple rows, but not so big that it wouldn't fit inside the image

Nathan Osman

1:15 AM

Or rather, here's where execution starts: github.com/nitroshare/nitroshare-android/blob/master/app/src/…

That is in response to an intent with a URI.

Android Dev

Thanks!

Nathan Osman

It handles ContentResolver.SCHEME_ANDROID_RESOURCE, ContentResolver.SCHEME_CONTENT, and ContentResolver.SCHEME_FILE.

Android Dev

Now if it still crashes even if you don't switch to another app to select it, then kill Android fragmentation with fire

That's the one good thing about Apple

Nathan Osman

In the end, all it really wants is a AssetFileDescriptor.

Unfortunately, I get another error...

04-29 18:18:39.772 12583 12617 I art     : Alloc concurrent mark sweep GC freed 5(120B) AllocSpace objects, 0(0B) LOS objects, 40% free, 19MB/32MB, paused 165us total 10.201ms
04-29 18:18:39.772 12583 12617 W art     : Throwing OutOfMemoryError "Failed to allocate a 1079009670 byte allocation with 13534976 free bytes and 236MB until OOM"
04-29 18:18:39.772 12583 12617 I art     : Starting a blocking GC Alloc
04-29 18:18:39.772 12583 12617 I art     : Starting a blocking GC Alloc
04-29 18:18:39.774 12583 12617 I art     : Starting a blocking GC Alloc

Out of memory.

It's trying to allocate a 1 GB block of memory...

Android Dev

Yup, I had that too when I selected the wrong image that didn't actually have embedded data

I'll need to fix that as well..

Nathan Osman

1:20 AM

But I selected the one you gave me.

Android Dev

But you're sure you selected the right image?

Okay, let me try again on my end to be sure

@NathanOsman So I downloaded the image I linked you to, and it ran fine...

So what the heck?

Nathan Osman

I have no idea.

Android Dev

Nathan Osman

FileSteg2Util.java:151 is where the 1 GB allocation is happening.

Android Dev

@NathanOsman Can you verify the hash of the image? I posted the hash above

And yes that's Windows 7... I don't have Ubuntu on this laptop ATM

Nathan Osman

1:25 AM

$ sha256sum stegoimage.webp
14ea38530ab30dd39b5c0a7b0bd5cb5b9918504ac477539eba1fdbddcee573ab  stegoimage.webp

Different hash for me.

Android Dev

Wait... what's with the .webp extension?

It should be .png

Nathan Osman

Is Google Drive doing something sketchy here?

Android Dev

Uhmmmmmm... but that makes no sense since I literally re-downloaded it 2 minutes ago!

Nathan Osman

AHA!

It was my fault.

I right-clicked the image and did "Save As..."

Instead of clicking the download link.

Sorry :)

Android Dev

That's what we have checksums for :)

Nathan Osman

1:27 AM

Let me try again...

Android Dev

I would delete the webp one first so you don't get mixed up

Nathan Osman

Okay, I've got the recovered data.

recovered_data.bin

Android Dev

Yay! Does it open in Libreoffice?

Nathan Osman

One sec.

Android Dev

Nathan Osman

1:32 AM

Oh, it's RTF.

I thought it was ODT.

It kept crashing LibreOffice Writer.

I guess that's a bug I should be reporting to them :P

Android Dev

Libreoffice can't open RTF?

What?

I've opened RTFs many times

Nathan Osman

It can.

It just won't open it if I give it an .odt extension.

RTF works fine - consider this test a success.

Android Dev

Ah

@NathanOsman Well, except for the 2 unhandled exceptions...

Nathan Osman

True.

Android Dev

It's so annoying that you have to catch the 17 billion possible exceptions... and present the user with a meaningful error message!

Now I'm starting to see why devs tend to have unhelpful error messages and usually use meaningless error codes.

Nathan Osman

1:47 AM

I usually just log the descriptive error as soon as it occurs and then just present a generic message to the user.

They aren't going to understand the technical jargon but they will understand that something went wrong.

And then if they want to tell you about it, they just send the logs.

(Which has your helpful message.)

TheWanderer

you see, I log the error and pop something up

with the error included

Android Dev

@NathanOsman - If you're still around could I get your advice on something?

Nathan Osman

2:05 AM

Just about to eat supper.

But if you ask, I can reply later.

Android Dev

@NathanOsman OK. So the way I get the number of bytes to extract from the image is by embedding the length of the byte array in the first 32 bits. But if you give it a random image, those 32 bits could be anything, which is why it tried to allocate 1GB of RAM for you...

So the way I was thinking about getting around that was to embed a checksum of the the first 32 bits and then regenerate the hash of the first 32 on extraction to verify that it is in fact an image with hidden data. Otherwise it would just show a pop-up saying that the image doesn't have embedded data. But I'd like to get your advice on how to do it

Maybe you can think of a much more elegant approach.

Also @TheWanderer feel free to chime in --^

TheWanderer

idk what you're talking about

Android Dev

My code

TheWanderer

so the guy at the T-Mobile store today told me that the V20 is having battery swelling problems

rip

Android Dev

Well then... Let's hope we don't have another Note 7 situation

TheWanderer

2:19 AM

well there's nothing in the news

but the V20 has a removable battery

so

Android Dev

Oh right I forgot

@TheWanderer Would you be interested in alpha testing my app too?

TheWanderer

wgats it do

Android Dev

Embeds files inside images

I still have a lot of work to do before the next test

I need to handle 2 excpetions

I need to change to getting the buffer instead of reading each pixel one at a time

Ubuntu Questions on U&L

4:08 AM

0

Q: VirtualBox Bridge Networking: doesn't work when my laptop is on Wifi

In my Virtual Machine. I have two network interfaces (both bridge mode, I need bridge mode because I want to create a server). One of them are Ethernet (eth0) and the another Wifi (wlan0) - In guest (Centos) they are represented as enp0s3 and enp0s8. I set static ip for them, but the connection ...

Zanna

4:26 AM

@DavidFoerster appreciate your comment on "give it a try gents" ;)

Nathan Osman

4:46 AM

Playing around with some textures in Blender:

Chan-Ho Suh

5:11 AM

that your living room? Some comfy seats and a dragon egg?

anyway, nice job, Nathan. Looks nice :)

Nathan Osman

Thanks :)

I found some textures and I was able to make some of them seamless. This was the test for them.

Rinzwind

6:14 AM

now make the egg hatch

btw looks good :)

Zanna

looks like a nice piece of stone rather than an egg

kind of rough

Nathan Osman

Yup, it's supposed to be a rock.

Zanna

very nice

Rinzwind

6:37 AM

but dragoneggs have a dragon inside. rocks are just rocks :P

Zanna

haha I got an audit in close votes and I tried to post a comment on the question, but a little red popup told me "This is an audit" -thanks for that small clue!

Rinzwind

yeah you can abuse it: hey this looks like an audit, lets make an edit :=)

Zanna

:)

Takkat

Got stuck in an entirely misconfigured mainboard yesterday... The external graphics card appeared to be broken. So I decided the internal would do. I switched VGA in BIOS only to realize that some genius of an engineer had disabled the internal GPU of that i7 system electro-mechanically for "speed". No big deal normally but that crippled BIOS can't be reset to use the external card.

Zanna

sounds painful....

Takkat

6:58 AM

horribly so... I even removed the CMOS battery and found the clear-CMOS jumpers. An this only because I promised to install Ubuntu.

Zanna

:(

Nathan Osman

@Takkat Did clearing the CMOS work?

And how does one disable the internal GPU? Isn't it quite literally printed on the same die as the CPU?

Journeyman Geek

7:14 AM

@Takkat 0_0

@NathanOsman you can disable it on the bios typically...

quite a lot of boards also shared pci lanes...

Takkat

7:33 AM

@NathanOsman it did not work... I suspect clearing made the BIOS use the diabled internal VGA... :(

The DVI-sockets on the board are dead.

Solution in the web is: replacing the mainboard.

(i.e. take one where the internal GPU was not disabled)

RobotHumans

8:21 AM

We may need a merge on this one

Zanna

@RobotHumans did you flag? I agree with you

RobotHumans

@Zanna I did not yet. Wanted confirmation

And flagged for merge

Zanna

flagged too :)

very confusing in the current state!

good call

time to go to work :/

Ubuntu Questions on U&L

9:04 AM

0

Q: sda and sdb keep on swapping

The box is a HP microserver, running Ubuntu 16.04. I recently "upgraded" the boot device to a 64GB SSD. Additionally there is a 1TB SATA drive. usually it boots up with /dev/sda1 as the primary partition (on the ssd) and /dev/sda5 as swap, and /dev/sdb1 pointing to the partition on the 1Tb hdd, ...

ubuntu fstab uuid

Rinzwind

10:44 AM

as OT as it can get askubuntu.com/questions/910425/…

Journeyman Geek

could be asking about windows ;p

Jacob Vlijm

@Rinzwind As OT as in OT en SIEN.

Android Dev

11:01 AM

@JacobVlijm Can you havev a look at the comments on this post? Do we need a mod to check out the user? askubuntu.com/questions/910093/…

He's posted this comment twice:

Android Dev, the situation I encountered make my guess I was attacked by hackers. Have you participated in them? What are you intended to do? — piratesailor 2 hours ago

And he seems really impatient:

Android Dev, do you really want to answer my question? What are you intended to do? — piratesailor yesterday

Android Dev, it's here: paste.ubuntu.com/24479260. Would you please diagnose it for me? — piratesailor 6 hours ago

Maybe you could have a look too @Rinzwind? --^

user136984

@AndroidDev: That's very strange... Almost as though he is suggesting that you are one of his hackers! :D

user136984

He's either crazy or something fishy is going on.

Android Dev

@ParanoidPanda I know right? And he's posted it twice, and he's very impatient. I'm on the edge of pinging Seth to have a look

user136984

@AndroidDev: I think you should, something is not quite right about this.

Android Dev

Alright.

Rinzwind

11:08 AM

@AndroidDev he's been on SO for 4 years >:)

O_o

damn

Mmkaaaayy

1 answer 12 q's and reached 9k people

wtf :D

what's he been doing? :X actual life?

user136984

You can be a long term member are still be crazy, I should know that... :P

Rinzwind

11:10 AM

yeah but you took your account name into that issue :=)

oh wait!!!!!1

he's been a pirate and sailing

doh!

Android Dev

@Seth Sorry to bother you again, but I think you should have a look at this post (specifically the comments) something isn't quite right... askubuntu.com/q/910093/518562

@Rinzwind I honestly wonder if his account got compromised?

user136984

@AndroidDev: That is a possilibity, maybe he is then one of the hackers he speaks of! :D

user136984

Wouldn't that be funny? :D

Android Dev

Yup :D

Rinzwind

almost time for F1 :=)

user136984

11:54 AM

@terdon: Do you know about this? :)

user136984

0

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