Bug 623637

Summary: [RHEL 4] Fix nfsd4 permissions problem
Product: Red Hat Enterprise Linux 4 Reporter: Sachin Prabhu <sprabhu>
Component: kernelAssignee: Red Hat Kernel Manager <kernel-mgr>
Status: CLOSED WONTFIX QA Contact: Red Hat Kernel QE team <kernel-qe>
Severity: medium Docs Contact:
Priority: medium    
Version: 4.8CC: jwest, moshiro
Target Milestone: rc   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2012-06-14 19:56:35 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---
Attachments:
Description Flags
User provided patch none

Description Sachin Prabhu 2010-08-12 11:30:08 UTC
We have a customer request to backport the following patch

commit 7fc90ec93a5eb71f4b08403baf5ba7176b3ec6b1
Author: J. Bruce Fields <bfields@citi.umich.edu>
Date:   Fri Jun 30 01:56:14 2006 -0700

    [PATCH] knfsd: nfsd: call nfsd_setuser() on fh_compose(), fix nfsd4 permissions problem

This patch also needs to be followed by

commit d1bbf14f37261c2c0dba71404602e1ddcec069d2
Author: NeilBrown <neilb@suse.de>
Date:   Sun Jul 30 03:03:16 2006 -0700

    [PATCH] knfsd: Fix stale file handle problem with subtree_checking.

which fixes a bug in the original patch.

Copying the description from the earlier patch

--
From: J. Bruce Fields <bfields@citi.umich.edu>

In the typical v2/v3 case the only new filehandles used as arguments to
operations are filehandles taken directly off the wire, which don't get
dentries until fh_verify() is called.

But in v4 the filehandles that are arguments to operations were often
created by previous operations (putrootfh, lookup, etc.) using
fh_compose, which sets the dentry in the filehandle without calling
nfsd_setuser().

This also means that, for example, if filesystem B is mounted on filesystem
A, and filesystem A is exported without root-squashing, then a client can
bypass the rootsquashing on B using a compound that starts at a filehandle
in A, crosses into B using lookups, and then does stuff in B.
--

Comment 2 Sachin Prabhu 2010-08-12 11:33:46 UTC
Created attachment 438406 [details]
User provided patch

Patch which combines the changes in 
git commits
7fc90ec93a5eb71f4b08403baf5ba7176b3ec6b1
and
d1bbf14f37261c2c0dba71404602e1ddcec069d2