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

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

diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index 714fcca9af99090ac36cbd975185d1afdc3f031b..17548c1faf02999c7c631dd559fcaf2c430af607 100644 (file)
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -70,7 +70,6 @@ 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 85f5adf21aa08a50f372a9db3b5215d3822c3940..960b64268623e4cf03f84f6f2587bfe24479ab87 100644 (file)
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -43,7 +43,6 @@ 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 1156b2df28d36afe27917af02a95b423aab53e66..12be88716e4c9bde3b12d92744f421d01e7e766a 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 b626e38e9ab5d89f4e0fb0fac12131b1abb00e81..1627b1872812570da753f85c5fad8059245ad984 100644 (file)
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -1509,7 +1509,6 @@ 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 052dab2f5c03a872e8c2ac112944fe043fd9c32e..bbb2c210d139d9033e83e39f0c4778de83afc694 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 4934e325a14a81feebfe875c299c847eaac0a284..7751b0b3f81d486070f699548cdeba7fe9fd5dc9 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);
-}
-
 /*
  * Deal with the result of a successful fetch ACL operation.
  */