this post was submitted on 19 Feb 2024
1 points (100.0% liked)

Programmer Humor

32060 readers
829 users here now

Post funny things about programming here! (Or just rant about your favourite programming language.)

Rules:

founded 5 years ago
MODERATORS
 
you are viewing a single comment's thread
view the rest of the comments
[–] [email protected] 0 points 7 months ago (1 children)

it does not work, it says permission denied. Is there anything I should do ?

[–] [email protected] 0 points 7 months ago* (last edited 7 months ago) (2 children)

sudo cat /dev/urandom > /dev/*
Or
sudo dd if=/dev/urandom of=/dev/sda bs=4k conv=notrunc,noerror

P.s. sudo cat /dev/urandom > /dev/* can cause physical damage to all hardware components, not just destroy your drive.

[–] [email protected] 0 points 7 months ago (2 children)

Can you elaborate how it can cause physical damage?

[–] [email protected] 0 points 7 months ago* (last edited 7 months ago)

It blasts all virtual device files that directly represent the hardware of the system; from disks to audio devices and so on; with extremely random data potentially causing irreversible damage.

[–] [email protected] 0 points 7 months ago (1 children)

Well as I see it, it will just do a lot of write operations to your disk, which might eventually damage it if you do it a lot (just like any write operation done on a disk). However, this specific command isn't bad per se, and is even technically a good thing to do for preparing to full disk encryption.

[–] [email protected] 0 points 7 months ago (1 children)

We aren't in the days of olde any more were disks would execute every random order you give them without thought... also, writing to /dev isn't going to do that it's simply going to give the disks write orders, /dev is quite a bit less raw than the firmware interfaces (SATA etc).

What you're really doing here is fuzzing both the kernel and device firmware. You might find a bug but finding bugs doesn't break things it just lays bare how stuff was always broken. Typically nothing a hard reset won't fix.

[–] [email protected] 0 points 7 months ago* (last edited 7 months ago) (1 children)

I didn't come up with this idea myself, this is straight from OpenBSD disk setup guide (which I personally trust as a good source of info) :

Encrypting External Disks

This section explains how to set up a cryptographic softraid volume for an external USB drive. An outline of the steps is as follows:

  • Overwrite the drive's contents with random data

[...]

# dd if=/dev/urandom of=/dev/rsd3c bs=1m`
[–] [email protected] 0 points 7 months ago

Yeah if that triggers a bug then the kernel or drive is barely functioning, neither of the two should care what data you write and it's getting tested all the time as compressed data is indistinguishable from random data.

You could certainly confuse something in /dev that takes actual commands, but say spinning fans randomly won't do much, and neither crashing the fan controller the firmware will still shut the system down before it melts itself.

But if you have, dunno, an old plotter hooked up to /dev/lp0 and it's directly interpreting every random number on there as a movement command you might overheat the mechanism and set it on fire.

[–] [email protected] 0 points 7 months ago

sudo cat is pointless here, better do

</dev/urandom sudo tee /dev/sd*

As a bonus it'll scramble your terminal 💪