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![David Howells](/assets/img/avatar_default.png)
commita7889c6320
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:ae46578b96
("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 [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@linuxfoundation.org>
225 lines
5 KiB
C
225 lines
5 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* mountpoint management
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*
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* Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/pagemap.h>
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#include <linux/mount.h>
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#include <linux/namei.h>
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#include <linux/gfp.h>
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#include <linux/fs_context.h>
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#include "internal.h"
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static struct dentry *afs_mntpt_lookup(struct inode *dir,
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struct dentry *dentry,
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unsigned int flags);
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static int afs_mntpt_open(struct inode *inode, struct file *file);
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static void afs_mntpt_expiry_timed_out(struct work_struct *work);
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const struct file_operations afs_mntpt_file_operations = {
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.open = afs_mntpt_open,
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.llseek = noop_llseek,
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};
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const struct inode_operations afs_mntpt_inode_operations = {
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.lookup = afs_mntpt_lookup,
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.readlink = page_readlink,
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.getattr = afs_getattr,
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};
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const struct inode_operations afs_autocell_inode_operations = {
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.getattr = afs_getattr,
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};
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static LIST_HEAD(afs_vfsmounts);
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static DECLARE_DELAYED_WORK(afs_mntpt_expiry_timer, afs_mntpt_expiry_timed_out);
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static unsigned long afs_mntpt_expiry_timeout = 10 * 60;
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static const char afs_root_volume[] = "root.cell";
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/*
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* no valid lookup procedure on this sort of dir
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*/
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static struct dentry *afs_mntpt_lookup(struct inode *dir,
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struct dentry *dentry,
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unsigned int flags)
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{
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_enter("%p,%p{%pd2}", dir, dentry, dentry);
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return ERR_PTR(-EREMOTE);
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}
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/*
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* no valid open procedure on this sort of dir
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*/
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static int afs_mntpt_open(struct inode *inode, struct file *file)
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{
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_enter("%p,%p{%pD2}", inode, file, file);
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return -EREMOTE;
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}
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/*
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* Set the parameters for the proposed superblock.
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*/
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static int afs_mntpt_set_params(struct fs_context *fc, struct dentry *mntpt)
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{
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struct afs_fs_context *ctx = fc->fs_private;
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struct afs_super_info *src_as = AFS_FS_S(mntpt->d_sb);
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struct afs_vnode *vnode = AFS_FS_I(d_inode(mntpt));
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struct afs_cell *cell;
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const char *p;
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int ret;
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if (fc->net_ns != src_as->net_ns) {
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put_net(fc->net_ns);
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fc->net_ns = get_net(src_as->net_ns);
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}
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if (src_as->volume && src_as->volume->type == AFSVL_RWVOL) {
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ctx->type = AFSVL_RWVOL;
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ctx->force = true;
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}
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if (ctx->cell) {
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afs_put_cell(ctx->net, ctx->cell);
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ctx->cell = NULL;
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}
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if (test_bit(AFS_VNODE_PSEUDODIR, &vnode->flags)) {
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/* if the directory is a pseudo directory, use the d_name */
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unsigned size = mntpt->d_name.len;
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if (size < 2)
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return -ENOENT;
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p = mntpt->d_name.name;
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if (mntpt->d_name.name[0] == '.') {
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size--;
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p++;
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ctx->type = AFSVL_RWVOL;
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ctx->force = true;
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}
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if (size > AFS_MAXCELLNAME)
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return -ENAMETOOLONG;
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cell = afs_lookup_cell(ctx->net, p, size, NULL, false);
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if (IS_ERR(cell)) {
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pr_err("kAFS: unable to lookup cell '%pd'\n", mntpt);
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return PTR_ERR(cell);
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}
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ctx->cell = cell;
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ctx->volname = afs_root_volume;
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ctx->volnamesz = sizeof(afs_root_volume) - 1;
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} else {
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/* read the contents of the AFS special symlink */
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struct page *page;
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loff_t size = i_size_read(d_inode(mntpt));
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char *buf;
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if (src_as->cell)
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ctx->cell = afs_get_cell(src_as->cell);
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if (size < 2 || size > PAGE_SIZE - 1)
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return -EINVAL;
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page = read_mapping_page(d_inode(mntpt)->i_mapping, 0, NULL);
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if (IS_ERR(page))
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return PTR_ERR(page);
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if (PageError(page)) {
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ret = afs_bad(AFS_FS_I(d_inode(mntpt)), afs_file_error_mntpt);
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put_page(page);
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return ret;
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}
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buf = kmap(page);
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ret = -EINVAL;
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if (buf[size - 1] == '.')
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ret = vfs_parse_fs_string(fc, "source", buf, size - 1);
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kunmap(page);
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put_page(page);
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if (ret < 0)
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return ret;
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}
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return 0;
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}
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/*
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* create a vfsmount to be automounted
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*/
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static struct vfsmount *afs_mntpt_do_automount(struct dentry *mntpt)
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{
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struct fs_context *fc;
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struct vfsmount *mnt;
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int ret;
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BUG_ON(!d_inode(mntpt));
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fc = fs_context_for_submount(&afs_fs_type, mntpt);
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if (IS_ERR(fc))
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return ERR_CAST(fc);
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ret = afs_mntpt_set_params(fc, mntpt);
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if (!ret)
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mnt = fc_mount(fc);
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else
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mnt = ERR_PTR(ret);
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put_fs_context(fc);
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return mnt;
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}
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/*
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* handle an automount point
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*/
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struct vfsmount *afs_d_automount(struct path *path)
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{
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struct vfsmount *newmnt;
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_enter("{%pd}", path->dentry);
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newmnt = afs_mntpt_do_automount(path->dentry);
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if (IS_ERR(newmnt))
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return newmnt;
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mntget(newmnt); /* prevent immediate expiration */
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mnt_set_expiry(newmnt, &afs_vfsmounts);
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queue_delayed_work(afs_wq, &afs_mntpt_expiry_timer,
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afs_mntpt_expiry_timeout * HZ);
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_leave(" = %p", newmnt);
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return newmnt;
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}
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/*
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* handle mountpoint expiry timer going off
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*/
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static void afs_mntpt_expiry_timed_out(struct work_struct *work)
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{
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_enter("");
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if (!list_empty(&afs_vfsmounts)) {
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mark_mounts_for_expiry(&afs_vfsmounts);
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queue_delayed_work(afs_wq, &afs_mntpt_expiry_timer,
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afs_mntpt_expiry_timeout * HZ);
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}
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_leave("");
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}
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/*
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* kill the AFS mountpoint timer if it's still running
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*/
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void afs_mntpt_kill_timer(void)
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{
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_enter("");
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ASSERT(list_empty(&afs_vfsmounts));
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cancel_delayed_work_sync(&afs_mntpt_expiry_timer);
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}
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