[Bugs] [Bug 1252072] New: POSIX ACLs as used by a FUSE mount can not use more than 32 groups

bugzilla at redhat.com bugzilla at redhat.com
Mon Aug 10 16:10:06 UTC 2015


https://bugzilla.redhat.com/show_bug.cgi?id=1252072

            Bug ID: 1252072
           Summary: POSIX ACLs as used by a FUSE mount can not use more
                    than 32 groups
           Product: GlusterFS
           Version: 3.6.3
         Component: fuse
          Keywords: Triaged
          Severity: medium
          Priority: medium
          Assignee: ndevos at redhat.com
          Reporter: ndevos at redhat.com
                CC: bugs at gluster.org, gluster-bugs at redhat.com
        Depends On: 1246275



+++ This bug was initially created as a clone of Bug #1246275 +++

Description of problem:
When enabling support for POSIX ACLs on a FUSE mount with the "-o acl" mount
option, permission checks only use the first 32 groups of a user. If
permissions of a directory/file are permitted by groups further in the
group-list, the permissions are not applied. The group-list of the user is
truncated to the fist 32 groups.

Version-Release number of selected component (if applicable):
mainline

How reproducible:
100%

Steps to Reproduce:
1. mount a volume with "-o acl"
2. create a lot of groups (33 or more)
3. create a user that belongs to a lot of groups
4. create a directory on the volume
5. add a POSIX ACL to the new directory, allow writes for the directory to the 
   last group the user belongs to (setfacl -m g:123456:rwx /path/new/dir)
6. create a new file in the director as the user

Actual results:
"Permission denied"

Expected results:
The user should be allowed to create the file, the user is member of the group
with write access.

Additional info:
If the number of groups the user belongs to is higher than ~93, the volume
option server.manage-gids needs to be enabled too.

--- Additional comment from Anand Avati on 2015-07-24 00:14:49 CEST ---

REVIEW: http://review.gluster.org/11732 (fuse: add "resolve-gids" mount option
to overcome 32-groups limit) posted (#2) for review on master by Niels de Vos
(ndevos at redhat.com)

--- Additional comment from Anand Avati on 2015-07-29 16:36:59 CEST ---

REVIEW: http://review.gluster.org/11732 (fuse: add "resolve-gids" mount option
to overcome 32-groups limit) posted (#3) for review on master by Niels de Vos
(ndevos at redhat.com)

--- Additional comment from Anand Avati on 2015-08-05 13:53:26 CEST ---

COMMIT: http://review.gluster.org/11732 committed in master by Kaleb KEITHLEY
(kkeithle at redhat.com) 
------
commit 64a5bf3749c67fcc00773a2716d0c7b61b0b4417
Author: Niels de Vos <ndevos at redhat.com>
Date:   Tue Jul 21 18:50:12 2015 +0200

    fuse: add "resolve-gids" mount option to overcome 32-groups limit

    Add a --resolve-gids commandline option to the glusterfs binary. This
    option gets set when executing "mount -t glusterfs -o resolve-gids ...".

    This option is most useful in combination with the "acl" mount option.
    POSIX ACL permission checking is done on the FUSE-client side to improve
    performance (in addition to the checking on the bricks).

    The fuse-bridge reads /proc/$PID/status by default, and this file
    contains maximum 32 groups. Any local (client-side) permission checking
    that requires more than the first 32 groups will fail.

    By enabling the "resolve-gids" option, the fuse-bridge will call
    getgrouplist() to retrieve all the groups from the user accessing the
    mountpoint. This is comparable to how "nfs.server-aux-gids" works.

    Note that when a user belongs to more than ~93 groups, the volume option
    server.manage-gids needs to be enabled too. Without this option, the
    RPC-layer will need to reduce the number of groups to make them fit in
    the RPC-header.

    Change-Id: I7ede90d0e41bcf55755cced5747fa0fb1699edb2
    BUG: 1246275
    Signed-off-by: Niels de Vos <ndevos at redhat.com>
    Reviewed-on: http://review.gluster.org/11732
    Tested-by: NetBSD Build System <jenkins at build.gluster.org>
    Reviewed-by: Ravishankar N <ravishankar at redhat.com>
    Tested-by: Gluster Build System <jenkins at build.gluster.com>
    Reviewed-by: jiffin tony Thottan <jthottan at redhat.com>
    Reviewed-by: Kaleb KEITHLEY <kkeithle at redhat.com>


Referenced Bugs:

https://bugzilla.redhat.com/show_bug.cgi?id=1246275
[Bug 1246275] POSIX ACLs as used by a FUSE mount can not use more than 32
groups
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