What's the meaning and effect of open_basedir ?

[tellmethis]

I currently have an installation of phpBB 3.3.10, which is hosted on what I think must be a Linux virtual server running PHP 7.3.23. Excuse any tech speak dumbness.

Users of the forum, including me, have intermittently experienced web browsers returning a blank page when access the forum. This will continue for a while, then suddenly the forum is functioning again. Then it'll be fine for a few days, then it'll be problematic for a few hours.

I've raised the issue numerous times with the server host. Historically the host has come back with "it's working fine", though that'll be a timing thing. Recently I pressed further with this. This statement has come back to me:

As you informed us earlier, the website <URL> goes down intermittently, we have investigated on this and checked the logs for the time this issue has occurred. Could you please verify if you have setup open_basedir for your forum? The error log shows that the website was going down due to open_basedir restriction

I have no clue how relevant open_basedir may be in regards to contributing to blank web browser pages, but so that I can at least answer the question from the server host, can somebody please point me to how I know whether open_basedir has been set up?

[ssl]

In general the host is able to lift/add exceptions to open_basedir restrictions because of security issues.

[Mick]

It would be helpful if we could see any clues in the server error logs so we can suggest what you need to say to your host. If you can’t get at the server logs ask your host to get them for you.

[tellmethis]

It would be helpful if we could see any clues in the server error logs so we can suggest what you need to say to your host. If you can’t get at the server logs ask your host to get them for you.

Thanks Mick. The host's reply did include an extract of the logs, however I didn't post here as I'm largely clueless as to whether they contain information that puts the site or server at risk. I've audaciously shot you a PM in case of interest or if you're happy to shed further light.

[Mick]

You need to get your host to look at/fix whatever it is that’s triggering the open_basedir exception but:

Could you please verify if you have setup open_basedir for your forum? The error log shows that the website was going down due to open_basedir restriction

Does this mean you’re self hosted?

[tellmethis]

Does this mean you’re self hosted?

This is another place I get lost, but in case this answers the question, I subscribe to "Web Hosting Platinum", which is one of the packages included on this page. I can log in to the server via Plesk, if that makes sense.

[Mick]

If you can get at the server settings look for open_basedir and see if you have access to it. If you have access as a test you can turn it off altogether and if that cures the problem explain to your host what you’ve done and suggest they whitelist whatever it is that’s triggering the error. Don’t forget to turn open_basedir back on when you’ve finished testing. You can also see the status of open_basedir in your PHP information in the ACP.

[tellmethis]

Thanks Mick.

Via ACP > PHP Information, the Directive for open_basedir shows ...

Code: Select all

/var/www/vhosts/knowles.net.au/:/tmp/

.. for both Local Value and Master Value. Does this indicate whether or not open_basedir has been set up?

[Mick]

Mine shows “no value” in both local and master values as I know my host doesn’t use it under normal conditions. If you have values in there I suspect it’s setup but with probable incorrect settings. Your error messages should point the host in the right direction. Sorry I can’t be of more help.

[tellmethis]

In case of interest to others in the future, I provided the server host with all information, including pointing to this topic, and has responded with:

We have removed the "open_basedir restriction" and the site is now up and loading fine

And indeed it is. Hopefully it stays that way.

How the server host did so I have no clue, however I checked back into ACP > PHP information, and now the line for open_basedir shows no value in each of the LOCAL VALUE and MASTER VALUE columns.

Appreciate all of the input along the way.

[tellmethis]

My ongoing saga.

As per my last post, the issue that I had may or may not be related to a new issue that I have.

Now, when a user navigates to the UCP, this displays in the top left of the browser window:

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[phpBB Debug] PHP Warning: in file [ROOT]/phpbb/db/driver/mysqli.php on line 264: mysqli_fetch_assoc(): Couldn't fetch mysqli_result
[phpBB Debug] PHP Warning: in file [ROOT]/phpbb/db/driver/mysqli.php on line 326: mysqli_free_result(): Couldn't fetch mysqli_result

The display of this PHP warning itself doesn't prevent a user seeing the UCP. However the problem was noticed when a user tried to navigate to Manage Attachments, at which point a blank page is returned.

I don't know whether it's a clue as to the cause, however whatever steps the server host took to rectify the initial problem reported (ie. opening post of this topic), the steps included:

It seems that the PHP version is changed from 7.4 to 7.3. We have updated the php version from php7.3 to 7.4 and the website start loading fine.

Any clues as to where to begin to fix this new issue