Subject: bug#35662: Really relocatable binaries crash with Permission denied

From: Ludovic Courtès <[email-masked]>
Date: Wed, 15 May 2019 18:15:19 +0200

Hi,

"pelzflorian (Florian Pelz)" <[email-masked]> skribis:

> Do I understand correctly that user namespaces are not really disabled
> (?) but fail on ZFS?

Correct.  Specifically, read-only bind mounts of (and to?) files that
reside on ZFS fail with EACCESS, which is normally “impossible.”

It would be great if you could ask the admins specifically what they did
in relation to user namespaces.

>> I don’t have any great option to offer.  You could perhaps modify
>> run-in-namespace.c so that it doesn’t even try user namespaces and
>> instead goes directly to the PRoot option?
>>
>> However working around this behavior of ZFS it not completely trivial
>> and I’m not sure we should put much energy to paper over non-standard
>> file system behavior.
>> 
>> Thoughts?
>>
>
> If ZFS makes user namespaces fail, then could run-un-namespace.c fall
> back to PRoot when detecting ZFS, somehow?

It’s code, so everything is possible :-), but like I wrote it’s a bit of
work, and it’s something that cannot happen (AFAIK) with file systems
that are part of Linux.

Thanks,
Ludo’.