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Created attachment 1039200 [details]
initial version of patch

Description of problem:

If a netgroup entry specifies an IP address, and that IP address can be resolved to a name, the current match code only tests whether the canonical name and any aliases are in the netgroup, and does not test whether the IP address is in the netgroup.

If the IP address does not resolve to a name, the IP does get checked for membership in the netgroup, as expected.

As far as I can tell, this affects all versions of nfs-utils, including upstream.


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

nfs-utils-1.2.3-54.el6.x86_64 (though appears to affect all versions)


How reproducible:

reproducer below


Steps to Reproduce:

/etc/netgroup:
test_netgroup	(127.0.0.1,-,-)

/etc/exports:
/data2		@test_netgroup(rw,sync)

# mkdir /data2
# mkdir -p /mnt/test
# exportfs -a
# mount localhost:/data2 /mnt/test


Actual results:

mount.nfs: access denied by server while mounting localhost:/data2

(this will fail, assuming that there's a localhost entry in /etc/hosts)


Expected results:

mount succeeds


Additional info:

I took a first crack at a patch for support/export/client.c.  It works, but probably needs fixing.

Posted patch to linux-nfs

http://thread.gmane.org/gmane.linux.nfs/74669

Created attachment 1086677 [details]
patch

(In reply to Frank Sorenson from comment #5)
> Posted patch to linux-nfs
> 
> http://thread.gmane.org/gmane.linux.nfs/74669

Unfortunately this patch causes the following regression
    https://bugzilla.redhat.com/show_bug.cgi?id=1284079

Follow-up patch to fix the regression posted to linux-nfs:

http://article.gmane.org/gmane.linux.nfs/75620

Created attachment 1105746 [details]
patch to fix the regression

The two needed upstream commits:
commit 4b5bd85481a45957122357feebfcd514550fc219
Author: Frank Sorenson <sorenson>
Date:   Wed Dec 16 10:12:38 2015 -0500

    mountd: fix netgroup lookup for short hostnames

commit 9a92ef6f194926904b1289e0ce1daecb42bd5e8b
Author: Frank Sorenson <sorenson>
Date:   Mon Nov 2 08:31:29 2015 -0500

    mountd: fix netgroup lookup for resolvable IP addresses

Move to VERIFIED as Comment 17

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2016-0868.html