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5556e7e6d3
Consider eCryptfs dcache entries to be stale when the corresponding lower inode's i_nlink count is zero. This solves a problem caused by the lower inode being directly modified, without going through the eCryptfs mount, leaving stale eCryptfs dentries cached and the eCryptfs inode's i_nlink count not being cleared. Signed-off-by: Tyler Hicks <tyhicks@canonical.com> Reported-by: Richard Weinberger <richard@nod.at> Cc: stable@vger.kernel.org
93 lines
2.6 KiB
C
93 lines
2.6 KiB
C
/**
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* eCryptfs: Linux filesystem encryption layer
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*
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* Copyright (C) 1997-2003 Erez Zadok
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* Copyright (C) 2001-2003 Stony Brook University
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* Copyright (C) 2004-2006 International Business Machines Corp.
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* Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
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* 02111-1307, USA.
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*/
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#include <linux/dcache.h>
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#include <linux/namei.h>
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#include <linux/mount.h>
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#include <linux/fs_stack.h>
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#include <linux/slab.h>
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#include "ecryptfs_kernel.h"
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/**
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* ecryptfs_d_revalidate - revalidate an ecryptfs dentry
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* @dentry: The ecryptfs dentry
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* @flags: lookup flags
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*
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* Called when the VFS needs to revalidate a dentry. This
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* is called whenever a name lookup finds a dentry in the
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* dcache. Most filesystems leave this as NULL, because all their
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* dentries in the dcache are valid.
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*
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* Returns 1 if valid, 0 otherwise.
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*
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*/
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static int ecryptfs_d_revalidate(struct dentry *dentry, unsigned int flags)
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{
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struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
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int rc = 1;
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if (flags & LOOKUP_RCU)
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return -ECHILD;
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if (lower_dentry->d_flags & DCACHE_OP_REVALIDATE)
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rc = lower_dentry->d_op->d_revalidate(lower_dentry, flags);
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if (d_really_is_positive(dentry)) {
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struct inode *inode = d_inode(dentry);
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fsstack_copy_attr_all(inode, ecryptfs_inode_to_lower(inode));
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if (!inode->i_nlink)
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return 0;
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}
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return rc;
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}
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struct kmem_cache *ecryptfs_dentry_info_cache;
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static void ecryptfs_dentry_free_rcu(struct rcu_head *head)
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{
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kmem_cache_free(ecryptfs_dentry_info_cache,
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container_of(head, struct ecryptfs_dentry_info, rcu));
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}
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/**
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* ecryptfs_d_release
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* @dentry: The ecryptfs dentry
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*
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* Called when a dentry is really deallocated.
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*/
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static void ecryptfs_d_release(struct dentry *dentry)
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{
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struct ecryptfs_dentry_info *p = dentry->d_fsdata;
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if (p) {
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path_put(&p->lower_path);
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call_rcu(&p->rcu, ecryptfs_dentry_free_rcu);
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}
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}
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const struct dentry_operations ecryptfs_dops = {
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.d_revalidate = ecryptfs_d_revalidate,
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.d_release = ecryptfs_d_release,
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};
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