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-   -   Is “obey pam restrictions” still supposed to work in Samba 4 ? (https://www.linuxquestions.org/questions/linux-server-73/is-%93obey-pam-restrictions%94-still-supposed-to-work-in-samba-4-a-4175690266/)

stoorky 02-10-2021 03:18 PM

Is “obey pam restrictions” still supposed to work in Samba 4 ?
 
Hi,

Working on Debian Buster 10.7 / Samba 4.9

The up-to-date Samba doc says (https://www.samba.org/samba/docs/cur...mb.conf.5.html) :

Quote:

When Samba 3.0 is configured to enable PAM support (i.e. --with-pam), this parameter will control whether or not Samba should obey PAM's account and session management directives.
Is this still supposed to work with Samba 4 ?

I had some strange result, it seems PAM's restrictions are enforced once, but then not anymore.

I tried to set up a file-size limitation on a Samba share. I'm not talking about quotas, I'm talking about preventing users from storing files that are bigger than 100MB, for example. I used /etc/security/limits.conf for this.

It almost works. Well, it works the first time a user tries to create a file, and then not anymore.

Here's what I did :

- First I defined a hard filesize limit of 100MB for user johndoe in /etc/security/limits.conf :
Code:

johndoe    hard    fsize    102400
- Then I added
Code:

session required pam_limits.so
to /etc/pam.d/samba, in order to tell PAM to enforce the limitations


- And finally, I added
Code:

obey pam restrictions = yes
to /etc/samba/smb.conf

At first it seemed promising, when user johndoe tries to copy a file > 100MB, a Windows 10 client throws the following error :
Quote:

An unexpected error is keeping you from copying the file...An unexpected network error occured
(see screenshot)

So far, so good ! That's what I wanted, prevent the user to store a file > 100MB

But if I click on "Try again", the file is copied anyway.

And if I then try to copy more files > 100MB, no more error message is thrown, and the copies proceed.

If user johndoe logs out and back in, same result : the first attempt at copying a file > 100MB throws an error, the following attempts succeed.

So, it seems the restriction I set in /etc/security/limits.conf is only enforced at the first attempt, and is no more enforced afterwards.

Any idea why ? Or any idea how I could achieve my goal (prevent a user to copy a file > 100MB) ?

stoorky 02-10-2021 04:04 PM

OK I got a straight answer from the Samba team

Basically, to sum things up, setting up a limit for individual file size can not be done with Samba

The full discussion can be found in the february mailing list archive (https://lists.samba.org/archive/samb...ebruary.txt.gz)


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