Strange hex dump output in sudo password prompt?

Jont828 · 2019-05-17 21:18:46

I've been having a strange issue where when I got into the TTY console and use any sudo command, it prompts me for my password and then outputs some strange text that looks a lot like a hex dump. Does anyone know where this output is coming from? Here's a screenshot of what I mean. Thanks1

Last edited by Jont828 (2019-05-17 21:26:04)

Trilby · 2019-05-17 21:48:23

Any command? Your screenshot shows your `sudo fbcat` command where the output obviously didn't corrupt the stdout or you'd not have that screenshot to post. It's not apparent from stderr either, unless it came out only after the screenshot was saved.

Is the output always the same, or does it depend on what command is used?

Can you post the output of the following:

type sudo
pacman -Qkk sudo
sudo grep '^[^#]' /etc/sudoers

seth · 2019-05-17 21:55:57

The second sudo has no pw prompt.
Does the output come before or after you enter the password?

The magic byte matches .ico, ie. an icon. Can you dumpt the output as text?
("sudo foo > text 2>&1")

Jont828 · 2019-05-18 00:23:59

Thanks for the replies! Mean to say that when it when it prompts me with "[sudo] password for jtong," and the output isn't sent to a file, the hex dump thing comes.

When I ran `pacman -Qkk` I got a problem with a file size mismatch. Here's a screenshot. Also, here should be the output.

0000 00 00 01 00 01 00 08 00  dd a6 4e 57 01 00 34 46  | ..........NW..4F
0010 02 00 07 00 60 39 00 00  01 00 84 08 01 00 07 00  | ....`9..........
0020 00 04 00 00 02 00 84 28  03 00 12 00 e0 10 00 00  | .......(........
0030 02 00 76 36 01 00 0c 00  10 0a 00 00 01 00 86 47  | ..v6...........G
0040 00 00 01 00 50 5a 00 00  02 00 23 77 00 00 01 00  | ....PZ....#w....
0050 80 2f 00 00 02 00 66 37  01 00 0c 00 f0 22 02 00  | ./....f7....."..
0060 01 00 25 56 00 00 01 00  70 04 00 00              | ..%V....p...

loqs · 2019-05-18 00:28:42

What is the contents of /etc/pam.d/sudo ?

Jont828 · 2019-05-18 01:07:42

Just this

#%PAM-1.0
auth		sufficient	pam_fingerprint-gui.so
auth		include		system-auth
account		include		system-auth
session		include		system-auth

Trilby · 2019-05-18 01:32:09

And if you comment out the fingerprint-gui line?

Jont828 · 2019-05-19 19:38:26

Thanks! That seems to have done the trick! Do you know if I need to fix the time-stamp and file size mismatch on /etc/pam.d/sudo and /etc/sudoers?

Trilby · 2019-05-19 19:45:03

No, it's expected that those files have changed if you've configued sudo. In fact the change to the pam file is documented in the wiki as one of the steps to using a fingerprint reader - yours just doesn't seem to be working properly. It's likely - given that seth suggested that's an .ico file - that fingerprint image data is getting dumped somehow. Unfortunately I have *zero* experience with fingerprint readers.

Are you even trying to use the fingerprint reader? You said you are entering a password.

Jont828 · 2019-05-20 20:53:58

I tried to configure fingerprint login a while back for Gnome shell but it didn't seem to work. I guess it must have modified some files.

Arch Linux

#1 2019-05-17 21:18:46

Strange hex dump output in sudo password prompt?

#2 2019-05-17 21:48:23

Re: Strange hex dump output in sudo password prompt?

#3 2019-05-17 21:55:57

Re: Strange hex dump output in sudo password prompt?

#4 2019-05-18 00:23:59

Re: Strange hex dump output in sudo password prompt?

#5 2019-05-18 00:28:42

Re: Strange hex dump output in sudo password prompt?

#6 2019-05-18 01:07:42

Re: Strange hex dump output in sudo password prompt?

#7 2019-05-18 01:32:09

Re: Strange hex dump output in sudo password prompt?

#8 2019-05-19 19:38:26

Re: Strange hex dump output in sudo password prompt?

#9 2019-05-19 19:45:03

Re: Strange hex dump output in sudo password prompt?

#10 2019-05-20 20:53:58

Re: Strange hex dump output in sudo password prompt?

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