Patch "afs: Stop listxattr() from listing "afs.*" attributes" has been added to the 5.11-stable tree

[gregkh at linuxfoundation.org]

This is a note to let you know that I've just added the patch titled

    afs: Stop listxattr() from listing "afs.*" attributes

to the 5.11-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     afs-stop-listxattr-from-listing-afs.-attributes.patch
and it can be found in the queue-5.11 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable at vger.kernel.org> know about it.


>From a7889c6320b9200e3fe415238f546db677310fa9 Mon Sep 17 00:00:00 2001
From: David Howells <dhowells at redhat.com>
Date: Tue, 9 Mar 2021 08:27:39 +0000
Subject: afs: Stop listxattr() from listing "afs.*" attributes

From: David Howells <dhowells at redhat.com>

commit a7889c6320b9200e3fe415238f546db677310fa9 upstream.

afs_listxattr() lists all the available special afs xattrs (i.e. those in
the "afs.*" space), no matter what type of server we're dealing with.  But
OpenAFS servers, for example, cannot deal with some of the extra-capable
attributes that AuriStor (YFS) servers provide.  Unfortunately, the
presence of the afs.yfs.* attributes causes errors[1] for anything that
tries to read them if the server is of the wrong type.

Fix the problem by removing afs_listxattr() so that none of the special
xattrs are listed (AFS doesn't support xattrs).  It does mean, however,
that getfattr won't list them, though they can still be accessed with
getxattr() and setxattr().

This can be tested with something like:

	getfattr -d -m ".*" /afs/example.com/path/to/file

With this change, none of the afs.* attributes should be visible.

Changes:
ver #2:
 - Hide all of the afs.* xattrs, not just the ACL ones.

Fixes: ae46578b963f ("afs: Get YFS ACLs and information through xattrs")
Reported-by: Gaja Sophie Peters <gaja.peters at math.uni-hamburg.de>
Signed-off-by: David Howells <dhowells at redhat.com>
Tested-by: Gaja Sophie Peters <gaja.peters at math.uni-hamburg.de>
Reviewed-by: Jeffrey Altman <jaltman at auristor.com>
Reviewed-by: Marc Dionne <marc.dionne at auristor.com>
cc: linux-afs at lists.infradead.org
Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003502.html [1]
Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003567.html # v1
Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003573.html # v2
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
---
 fs/afs/dir.c      |    1 -
 fs/afs/file.c     |    1 -
 fs/afs/inode.c    |    1 -
 fs/afs/internal.h |    1 -
 fs/afs/mntpt.c    |    1 -
 fs/afs/xattr.c    |   23 -----------------------
 6 files changed, 28 deletions(-)

--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -69,7 +69,6 @@ const struct inode_operations afs_dir_in
 	.permission	= afs_permission,
 	.getattr	= afs_getattr,
 	.setattr	= afs_setattr,
-	.listxattr	= afs_listxattr,
 };
 
 const struct address_space_operations afs_dir_aops = {
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -43,7 +43,6 @@ const struct inode_operations afs_file_i
 	.getattr	= afs_getattr,
 	.setattr	= afs_setattr,
 	.permission	= afs_permission,
-	.listxattr	= afs_listxattr,
 };
 
 const struct address_space_operations afs_fs_aops = {
--- a/fs/afs/inode.c
+++ b/fs/afs/inode.c
@@ -27,7 +27,6 @@
 
 static const struct inode_operations afs_symlink_inode_operations = {
 	.get_link	= page_get_link,
-	.listxattr	= afs_listxattr,
 };
 
 static noinline void dump_vnode(struct afs_vnode *vnode, struct afs_vnode *parent_vnode)
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -1508,7 +1508,6 @@ extern int afs_launder_page(struct page
  * xattr.c
  */
 extern const struct xattr_handler *afs_xattr_handlers[];
-extern ssize_t afs_listxattr(struct dentry *, char *, size_t);
 
 /*
  * yfsclient.c
--- a/fs/afs/mntpt.c
+++ b/fs/afs/mntpt.c
@@ -32,7 +32,6 @@ const struct inode_operations afs_mntpt_
 	.lookup		= afs_mntpt_lookup,
 	.readlink	= page_readlink,
 	.getattr	= afs_getattr,
-	.listxattr	= afs_listxattr,
 };
 
 const struct inode_operations afs_autocell_inode_operations = {
--- a/fs/afs/xattr.c
+++ b/fs/afs/xattr.c
@@ -11,29 +11,6 @@
 #include <linux/xattr.h>
 #include "internal.h"
 
-static const char afs_xattr_list[] =
-	"afs.acl\0"
-	"afs.cell\0"
-	"afs.fid\0"
-	"afs.volume\0"
-	"afs.yfs.acl\0"
-	"afs.yfs.acl_inherited\0"
-	"afs.yfs.acl_num_cleaned\0"
-	"afs.yfs.vol_acl";
-
-/*
- * Retrieve a list of the supported xattrs.
- */
-ssize_t afs_listxattr(struct dentry *dentry, char *buffer, size_t size)
-{
-	if (size == 0)
-		return sizeof(afs_xattr_list);
-	if (size < sizeof(afs_xattr_list))
-		return -ERANGE;
-	memcpy(buffer, afs_xattr_list, sizeof(afs_xattr_list));
-	return sizeof(afs_xattr_list);
-}
-
 /*
  * Deal with the result of a successful fetch ACL operation.
  */


Patches currently in stable-queue which might be from dhowells at redhat.com are

queue-5.11/afs-stop-listxattr-from-listing-afs.-attributes.patch
queue-5.11/afs-fix-accessing-yfs-xattrs-on-a-non-yfs-server.patch