Re: zfs howto

[Chavdar Ivanov <ci4ic4%gmail.com@localhost>]

Awesome, thanks! Fix confirmed.

On Sun, 14 Feb 2021 at 09:35, J. Hannken-Illjes <hannken%eis.cs.tu-bs.de@localhost> wrote:
>
> > On 14. Feb 2021, at 02:55, Brad Spencer <brad%anduin.eldar.org@localhost> wrote:
> >
> > Chavdar Ivanov <ci4ic4%gmail.com@localhost> writes:
> >
> > [snip]
> >
> >>> I am not sure of the complete context of the statement, but I do this
> >>> all of the time with normal NetBSD NFS against a ZFS fileset.
> >>>
> >>> build% cat /etc/exports
> >>> /usr/installed_src/PKGSRC_2018Q4 -alldirs -maproot=root anotherbuild.system.eldar.org
> >>>
> >>> build% zfs list /usr/installed_src/PKGSRC_2018Q4
> >>> NAME                               USED  AVAIL  REFER  MOUNTPOINT
> >>> tank/installed_src/PKGSRC_2018Q4   414M   250G   414M  /usr/installed_src/PKGSRC_2018Q4
> >>>
> >>>
> >>> These are DOMUs running NetBSD 9.0_STABLE from around September.  I have
> >>> not tried this with -current, but there are no crashes for me with 9.x.
> >
> > [snip]
> >
> >>
> >> I got it ---
> >>
> >> With the following entry in -etc-exports:
> >>
> >>     /tank/t1 -maproot=0:10 -network 192.168.0/24
> >>
> >> the NFS server crashes when /tank/t1 is zfs system.
> >>
> >> With the following one:
> >>
> >>     /tank/t1 -maproot=root -network 192.168.0/24
> >>
> >> it works fine.
> >>
> >> Mind you, '-maproot=0:10' is the first example from 'man exports' ...
>
> The trigger is '-maproot' with group(s), first bug is mountd leaving
> 'cr_gid' as -2 and setting the first group list member to 10 in this case.
>
> Second bug is ZFS setting illegal group id -2 aka 4294967294 to GID_NOBODY
> with id -2.  Later this illegal id leads to null pointer dereference
> in zfs_log_create() at zfs_log.c:297 "lr->lr_gid = fuidp->z_fuid_group"
> where fuidp is NULL.
>
> With the attached diff the ZFS bug gets fixed and your export works.
>
> > Glad to see that it isn't totally broken.  I am by no means an expert in
> > the ZFS code, and I am not in a position to take a lot of time looking
> > at it right now, but if the trace back in the PR is correct, it makes it
> > almost totally though the mkdir call and crashes in the log create step
> > after the directory node is created.  I am trying not to speculate too
> > much here, but the code may fail to handle the group in the exports
> > line.
> >
> >
> >
> >
> >
> >
> > --
> > Brad Spencer - brad%anduin.eldar.org@localhost - KC8VKS - http://anduin.eldar.org
>
> --
> J. Hannken-Illjes - hannken%eis.cs.tu-bs.de@localhost - TU Braunschweig



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