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

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@math.uni-hamburg.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Gaja Sophie Peters <gaja.peters@math.uni-hamburg.de>
Reviewed-by: Jeffrey Altman <jaltman@auristor.com>
Reviewed-by: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003502.html
Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003567.html
Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003573.html
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index 3c486340b22085f8e23bec6780a5d0dad16468b8..e7494cd49ce7bcab9ed7c8632facac9963248f91 100644 (file)
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -69,7 +69,6 @@ const struct inode_operations afs_dir_inode_operations = {
        .permission     = afs_permission,
        .getattr        = afs_getattr,
        .setattr        = afs_setattr,
-       .listxattr      = afs_listxattr,
 };
 
 const struct address_space_operations afs_dir_aops = {

diff --git a/fs/afs/file.c b/fs/afs/file.c
index dd3c55c9101c4e8475eca6a66e789a5f991d845d..5d0b472e984ba911ff0a5802ceb60bd9a967b882 100644 (file)
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -42,7 +42,6 @@ const struct inode_operations afs_file_inode_operations = {
        .getattr        = afs_getattr,
        .setattr        = afs_setattr,
        .permission     = afs_permission,
-       .listxattr      = afs_listxattr,
 };
 
 const struct address_space_operations afs_fs_aops = {

diff --git a/fs/afs/inode.c b/fs/afs/inode.c
index a74e8e209454be076fcabd5ea5265009fa629acc..4f58b28a1edd28a321b9a9ff894e4a20cf1f2a7f 100644 (file)
--- 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)

diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 7fe88d918b23857c51821e25596945a3f667662d..c3ad582f9fd0ea907a3ba03a537549473d13d66a 100644 (file)
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -1354,7 +1354,6 @@ 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

diff --git a/fs/afs/mntpt.c b/fs/afs/mntpt.c
index 79bc5f1338edfb51e98f67ca47e167c32c903f18..f105f061e89bb09bdcfdd407dfe9859c6c3f0499 100644 (file)
--- a/fs/afs/mntpt.c
+++ b/fs/afs/mntpt.c
@@ -32,7 +32,6 @@ const struct inode_operations afs_mntpt_inode_operations = {
        .lookup         = afs_mntpt_lookup,
        .readlink       = page_readlink,
        .getattr        = afs_getattr,
-       .listxattr      = afs_listxattr,
 };
 
 const struct inode_operations afs_autocell_inode_operations = {

diff --git a/fs/afs/xattr.c b/fs/afs/xattr.c
index 5552d034090af8ce985d907469261b2cc3d46d18..13292d4ca860cd0781f7d70a57bcf1892a0f1f0d 100644 (file)
--- 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);
-}
-
 /*
  * Get a file's ACL.
  */