Unable to open a file with Read group permission

Dominique Morales

5/26/24, 6:39 PM

I am trying to grant users read-only access to directory (conf) contents, so I added a user(dev1) to a group (tomcat) and set the group permission to g+r. I have the following user:group

1) tomcat:tomcat
2) dev1:developers

I have the following file and directory permissions:

dev1@athena:~$ ls -la /opt
drwxr-xr-x  6 root     root     4096 May 26 11:24 .
drwxr-xr-x 19 root     root     4096 May 20 15:09 ..
drwxr-xr-x  9 tomcat   tomcat   4096 May 26 10:34 apache-tomcat-10.1.9
lrwxrwxrwx  1 tomcat   tomcat     25 May 26 11:24 tomcat -> /opt/apache-tomcat-10.1.9

dev1@athena:~$ ls -la /opt/tomcat/ 
drwxr-xr-x 9 tomcat tomcat  4096 May 26 10:34 . 
drwxr-xr-x 6 root   root    4096 May 26 11:24 .. 
drwxr----- 3 tomcat tomcat  4096 May 26 16:02 conf
    
dev1@athena:~$ sudo ls -la /opt/tomcat/conf 
drwxr----- 3 tomcat tomcat 4096 May 26 16:02 . 
drwxr-xr-x 9 tomcat tomcat   4096 May 26 10:34 ..
-rw-r----- 1 tomcat tomcat   1411 May  9 14:30 context.xml
-rw-r----- 1 tomcat tomcat   6985 May 26 10:57 server.xml
-rw-r----- 1 tomcat tomcat 172391 May  9 14:30 web.xml

Note: I deleted some ls entries for brevity.

I configured dev1 to be a member of the tomcat group and verified, like so:

dev1@athena:~$ sudo usermod -aG tomcat dev1
dev1@athena:~$ groups
developers sudo tomcat
dev1@athena:~$ id
uid=1002(dev1) gid=1002(developers) groups=1002(developers),27(sudo),1001(tomcat)

I have logged out and login as dev1 and even restarted the VM. However, when I try to open server.xml using vi, I get a Permission Denied error

dev1@athena:~$ vi /opt/tomcat/conf/server.xml
  ...
  "/opt/tomcat/conf/server.xml" [Permission Denied]

When I try to list the contents of /opt/tomcat/conf, I also get Permission Denied error.

ls -la /opt/tomcat/conf
ls: cannot open directory '/opt/tomcat/conf': Permission denied

What permission did I miss to allow dev1 read-only access to the contents of /opt/tomcat/conf directory? Have I misunderstood Linux file permissions?

Additional info:

Version: Ubuntu Live Server 22.04.2
VM: VMWare Fusion 13.0.0
OS: Macos (M1) Monterey

Any help will be greatly appreciated. Thanks in advance.

0 + 3

permissions

steeldriver

5/26/24, 8:00 PM

See [Accessing files in a directory without x-permission?](https://askubuntu.com/questions/83788/accessing-files-in-a-directory-without-x-permission)

waltinator

5/26/24, 8:03 PM

Explore your Mount/Read/Write/Execute problems with `https://github.com/waltinator/pathlld`, a `bash` script to show the permissions, mount options along the path to an object or objects.

Dominique Morales

5/28/24, 3:45 PM

@steeldriver Thanks for the link. I added g+x permission to make it work.

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Unable to open a file with Read group permission

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