What were you trying to do that didn't work?

The "dirname $0" command in a script is giving a strange output when a sha256 checksum is added to a sudo rule.

[root@vm251-174 scripts]# cat /scripts/test1
#!/bin/sh
dirname $0
[root@vm251-174 scripts]# cat /scripts/test2
#!/bin/sh
dirname $0

[test@vm251-174 scripts]$ echo $SHELL
/bin/bash

[test@vm251-174 scripts]$ sudo /scripts/test1
/scripts
[test@vm251-174 scripts]$ sudo /scripts/test2
/dev/fd <----------------------------------------- Here the expected output is "/scripts"

Please provide the package NVR for which bug is seen:

sudo-1.9.5p2-1.el8_9.x86_64
sudo-1.9.5p2-10.el9_3.x86_64

How reproducible:

Always, reproducible

Steps to reproduce

[1] Create the following files:

1. mkdir /scripts
2. echo $'#!/bin/sh \ndirname $0' > /scripts/test1
3. echo $'#!/bin/sh \ndirname $0' > /scripts/tes2
4. chmod a+x /scripts/test1 /scripts/test2

[2] Create a test user:

1. useradd test
2. passwd test

[3] Add the following lines to sudoers:

1. tail -2 /etc/sudoers
   test ALL = NOPASSWD: /scripts/test1
   test ALL = NOPASSWD: sha256:86395225936899a345cb4bed5b3d0a570dcfcbf5b19488517c53cc24a5bcceb2 /scripts/test2

[4] Execute /scripts/test1 and /scripts/test2 scrupts using sudo:

1. su test
   $ sudo /scripts/test1
   $ sudo /scripts/test2

Expected results

$ sudo /scripts/test1
/scripts
$ sudo /scripts/test2
/dev/fd <----------------------------------------- Here the expected output should be "/scripts"

Actual results

$ sudo /scripts/test1
/scripts
$ sudo /scripts/test2
/dev/fd

Is this expected behavior or a bug?

Is there any scope to change this behavior?

Can sudo replace FD with actual file once validation is done?