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From: ebiederm@xmission.com (Eric W. Biederman)
To: Linux Containers <containers@lists.linux-foundation.org>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Subject: Use cases for multiple uid mapping?
Date: Fri, 28 Aug 2020 10:17:16 -0500	[thread overview]
Message-ID: <87zh6eiyv7.fsf@x220.int.ebiederm.org> (raw)


We had a discussion in the hackroom at LPC talking about use cases for
a shiftfs style setup where there are different mappings of uids to
disk.

In the discussion we had a couple of ideas of kernel developments
we should look at that address some of these.

- Fix rlimits in user namespaces (This potentially allows multiple
  containers to run with the same userids simplifying the mapping
  problem).

- Look at extending kuid_t to 64bits and using the highbits to
  implement uids that are private to user namespaces and don't
  map out.
  
- Look at ways for allowing setgroups unprivileged.


Together this has the potential that the existing uid & gid mappings
will be able to function the same as the proposed fusid mappings. Fingers crossed.


I had some problems with audio and a lot of people were talking
quickly.  So I did not manage to capture everyone's use cases.   And I
definitely was not able to see how everyone's use cases interacted with
the changes we are looking at.

I know for certain I missed Serge's usecase (apologies).

Can people follow up to this and report their use cases?

There are some real challenges and I would like to see if we
can solve them, while avoiding scary problems like changing
uids on write.

Eric







  


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             reply	other threads:[~2020-08-28 15:21 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-28 15:17 Eric W. Biederman [this message]
2020-08-28 15:55 ` Use cases for multiple uid mapping? Stéphane Graber via Containers
2020-08-28 17:03   ` Sargun Dhillon
2020-08-30  5:48 ` James Bottomley
2020-09-01  6:06 ` Serge E. Hallyn
2020-09-01 14:53   ` Eric W. Biederman
2020-09-24 17:09     ` Alban Crequy
2020-09-25  8:13       ` Christian Brauner

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