Users can write data outside their directory (via SSH)

Virtualmin
1

Hallo everyone,

I know the topic of SSH and user’s permissions was discussed many times, but I haven’t found reason / solution for this:

  1. I create new server with one user - this user has SSH access by default, into his home directory /home/user

  2. If I login via SSH like this user, I can access folders like /etc /var and others - this is known “issue”

  3. But what I didn’t figured out, why this user can write into /etc /var and others?

The problem is, that this user can use e.g. folder /tmp like the storage no matter the limitations of his account. Or he can just mess my system everywhere :frowning:

Is this bug, or the classic behaviour?

Thanks for reply, best regards

Nikos

2

Howdy,

Users can read and write to any directory they have permission to access – and usually the default setup is secure :slight_smile: There’s some details on that here:

http://www.virtualmin.com/documentation/security/faq

A user bring able to write to /tmp is normal – that’s what /tmp is there for.

A user can read some things in /etc and /var by default, but shouldn’t be able to write to it. Are you sure the user is actually able to write, and not just read?

-Eric

3

Oh, you are right. They can’t write to all directories like /etc. Thanks for the link - that cleared my doubts :-).

Just last question - if I set data size limitation for virtual server - etc. 100MB - can the user write to the /tmp directory more than 100MB?

4

he can not

5

Howdy,

Helpmin is correct – so long as your /tmp directory is on the same partition as /home – your user quotas apply to both directories.

-Eric