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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Olga Kornievskaia <kolga@netapp.com>,
        Trond Myklebust <trond.myklebust@hammerspace.com>
Subject: [PATCH 5.16 0067/1017] NFS: NFSv2/v3 clients should never be setting NFS_CAP_XATTR
Date:   Tue,  5 Apr 2022 09:16:20 +0200
Message-Id: <20220405070356.177860477@linuxfoundation.org>
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From: Trond Myklebust <trond.myklebust@hammerspace.com>

commit b622ffe1d9ecbac71f0cddb52ff0831efdf8fb83 upstream.

Ensure that we always initialise the 'xattr_support' field in struct
nfs_fsinfo, so that nfs_server_set_fsinfo() doesn't declare our NFSv2/v3
client to be capable of supporting the NFSv4.2 xattr protocol by setting
the NFS_CAP_XATTR capability.

This configuration can cause nfs_do_access() to set access mode bits
that are unsupported by the NFSv3 ACCESS call, which may confuse
spec-compliant servers.

Reported-by: Olga Kornievskaia <kolga@netapp.com>
Fixes: b78ef845c35d ("NFSv4.2: query the server for extended attribute support")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/nfs/nfs3xdr.c |    1 +
 fs/nfs/proc.c    |    1 +
 2 files changed, 2 insertions(+)

--- a/fs/nfs/nfs3xdr.c
+++ b/fs/nfs/nfs3xdr.c
@@ -2228,6 +2228,7 @@ static int decode_fsinfo3resok(struct xd
 	/* ignore properties */
 	result->lease_time = 0;
 	result->change_attr_type = NFS4_CHANGE_TYPE_IS_UNDEFINED;
+	result->xattr_support = 0;
 	return 0;
 }
 
--- a/fs/nfs/proc.c
+++ b/fs/nfs/proc.c
@@ -92,6 +92,7 @@ nfs_proc_get_root(struct nfs_server *ser
 	info->maxfilesize = 0x7FFFFFFF;
 	info->lease_time = 0;
 	info->change_attr_type = NFS4_CHANGE_TYPE_IS_UNDEFINED;
+	info->xattr_support = 0;
 	return 0;
 }