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424 lines
11 KiB
424 lines
11 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* eCryptfs: Linux filesystem encryption layer |
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* |
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* Copyright (C) 1997-2004 Erez Zadok |
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* Copyright (C) 2001-2004 Stony Brook University |
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* Copyright (C) 2004-2007 International Business Machines Corp. |
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* Author(s): Michael A. Halcrow <[email protected]> |
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* Michael C. Thompson <[email protected]> |
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*/ |
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#include <linux/file.h> |
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#include <linux/poll.h> |
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#include <linux/slab.h> |
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#include <linux/mount.h> |
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#include <linux/pagemap.h> |
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#include <linux/security.h> |
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#include <linux/compat.h> |
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#include <linux/fs_stack.h> |
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#include "ecryptfs_kernel.h" |
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|
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/* |
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* ecryptfs_read_update_atime |
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* |
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* generic_file_read updates the atime of upper layer inode. But, it |
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* doesn't give us a chance to update the atime of the lower layer |
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* inode. This function is a wrapper to generic_file_read. It |
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* updates the atime of the lower level inode if generic_file_read |
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* returns without any errors. This is to be used only for file reads. |
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* The function to be used for directory reads is ecryptfs_read. |
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*/ |
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static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb, |
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struct iov_iter *to) |
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{ |
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ssize_t rc; |
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struct path *path; |
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struct file *file = iocb->ki_filp; |
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|
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rc = generic_file_read_iter(iocb, to); |
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if (rc >= 0) { |
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path = ecryptfs_dentry_to_lower_path(file->f_path.dentry); |
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touch_atime(path); |
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} |
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return rc; |
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} |
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struct ecryptfs_getdents_callback { |
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struct dir_context ctx; |
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struct dir_context *caller; |
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struct super_block *sb; |
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int filldir_called; |
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int entries_written; |
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}; |
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/* Inspired by generic filldir in fs/readdir.c */ |
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static int |
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ecryptfs_filldir(struct dir_context *ctx, const char *lower_name, |
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int lower_namelen, loff_t offset, u64 ino, unsigned int d_type) |
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{ |
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struct ecryptfs_getdents_callback *buf = |
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container_of(ctx, struct ecryptfs_getdents_callback, ctx); |
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size_t name_size; |
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char *name; |
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int rc; |
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buf->filldir_called++; |
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rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size, |
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buf->sb, lower_name, |
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lower_namelen); |
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if (rc) { |
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if (rc != -EINVAL) { |
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ecryptfs_printk(KERN_DEBUG, |
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"%s: Error attempting to decode and decrypt filename [%s]; rc = [%d]\n", |
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__func__, lower_name, rc); |
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return rc; |
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} |
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|
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/* Mask -EINVAL errors as these are most likely due a plaintext |
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* filename present in the lower filesystem despite filename |
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* encryption being enabled. One unavoidable example would be |
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* the "lost+found" dentry in the root directory of an Ext4 |
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* filesystem. |
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*/ |
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return 0; |
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} |
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buf->caller->pos = buf->ctx.pos; |
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rc = !dir_emit(buf->caller, name, name_size, ino, d_type); |
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kfree(name); |
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if (!rc) |
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buf->entries_written++; |
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return rc; |
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} |
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/** |
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* ecryptfs_readdir |
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* @file: The eCryptfs directory file |
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* @ctx: The actor to feed the entries to |
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*/ |
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static int ecryptfs_readdir(struct file *file, struct dir_context *ctx) |
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{ |
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int rc; |
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struct file *lower_file; |
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struct inode *inode = file_inode(file); |
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struct ecryptfs_getdents_callback buf = { |
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.ctx.actor = ecryptfs_filldir, |
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.caller = ctx, |
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.sb = inode->i_sb, |
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}; |
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lower_file = ecryptfs_file_to_lower(file); |
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rc = iterate_dir(lower_file, &buf.ctx); |
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ctx->pos = buf.ctx.pos; |
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if (rc < 0) |
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goto out; |
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if (buf.filldir_called && !buf.entries_written) |
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goto out; |
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if (rc >= 0) |
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fsstack_copy_attr_atime(inode, |
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file_inode(lower_file)); |
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out: |
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return rc; |
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} |
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struct kmem_cache *ecryptfs_file_info_cache; |
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static int read_or_initialize_metadata(struct dentry *dentry) |
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{ |
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struct inode *inode = d_inode(dentry); |
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struct ecryptfs_mount_crypt_stat *mount_crypt_stat; |
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struct ecryptfs_crypt_stat *crypt_stat; |
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int rc; |
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crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; |
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mount_crypt_stat = &ecryptfs_superblock_to_private( |
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inode->i_sb)->mount_crypt_stat; |
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mutex_lock(&crypt_stat->cs_mutex); |
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if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED && |
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crypt_stat->flags & ECRYPTFS_KEY_VALID) { |
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rc = 0; |
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goto out; |
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} |
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rc = ecryptfs_read_metadata(dentry); |
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if (!rc) |
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goto out; |
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if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) { |
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crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED |
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| ECRYPTFS_ENCRYPTED); |
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rc = 0; |
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goto out; |
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} |
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if (!(mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) && |
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!i_size_read(ecryptfs_inode_to_lower(inode))) { |
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rc = ecryptfs_initialize_file(dentry, inode); |
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if (!rc) |
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goto out; |
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} |
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rc = -EIO; |
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out: |
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mutex_unlock(&crypt_stat->cs_mutex); |
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return rc; |
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} |
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static int ecryptfs_mmap(struct file *file, struct vm_area_struct *vma) |
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{ |
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struct file *lower_file = ecryptfs_file_to_lower(file); |
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/* |
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* Don't allow mmap on top of file systems that don't support it |
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* natively. If FILESYSTEM_MAX_STACK_DEPTH > 2 or ecryptfs |
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* allows recursive mounting, this will need to be extended. |
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*/ |
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if (!lower_file->f_op->mmap) |
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return -ENODEV; |
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return generic_file_mmap(file, vma); |
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} |
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/** |
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* ecryptfs_open |
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* @inode: inode specifying file to open |
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* @file: Structure to return filled in |
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* |
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* Opens the file specified by inode. |
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* |
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* Returns zero on success; non-zero otherwise |
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*/ |
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static int ecryptfs_open(struct inode *inode, struct file *file) |
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{ |
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int rc = 0; |
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struct ecryptfs_crypt_stat *crypt_stat = NULL; |
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struct dentry *ecryptfs_dentry = file->f_path.dentry; |
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/* Private value of ecryptfs_dentry allocated in |
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* ecryptfs_lookup() */ |
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struct ecryptfs_file_info *file_info; |
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/* Released in ecryptfs_release or end of function if failure */ |
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file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL); |
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ecryptfs_set_file_private(file, file_info); |
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if (!file_info) { |
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ecryptfs_printk(KERN_ERR, |
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"Error attempting to allocate memory\n"); |
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rc = -ENOMEM; |
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goto out; |
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} |
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crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; |
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mutex_lock(&crypt_stat->cs_mutex); |
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if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) { |
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ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n"); |
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/* Policy code enabled in future release */ |
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crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED |
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| ECRYPTFS_ENCRYPTED); |
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} |
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mutex_unlock(&crypt_stat->cs_mutex); |
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rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode); |
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if (rc) { |
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printk(KERN_ERR "%s: Error attempting to initialize " |
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"the lower file for the dentry with name " |
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"[%pd]; rc = [%d]\n", __func__, |
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ecryptfs_dentry, rc); |
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goto out_free; |
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} |
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if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE) |
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== O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) { |
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rc = -EPERM; |
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printk(KERN_WARNING "%s: Lower file is RO; eCryptfs " |
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"file must hence be opened RO\n", __func__); |
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goto out_put; |
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} |
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ecryptfs_set_file_lower( |
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file, ecryptfs_inode_to_private(inode)->lower_file); |
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rc = read_or_initialize_metadata(ecryptfs_dentry); |
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if (rc) |
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goto out_put; |
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ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = " |
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"[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino, |
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(unsigned long long)i_size_read(inode)); |
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goto out; |
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out_put: |
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ecryptfs_put_lower_file(inode); |
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out_free: |
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kmem_cache_free(ecryptfs_file_info_cache, |
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ecryptfs_file_to_private(file)); |
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out: |
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return rc; |
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} |
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/** |
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* ecryptfs_dir_open |
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* @inode: inode specifying file to open |
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* @file: Structure to return filled in |
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* |
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* Opens the file specified by inode. |
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* |
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* Returns zero on success; non-zero otherwise |
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*/ |
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static int ecryptfs_dir_open(struct inode *inode, struct file *file) |
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{ |
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struct dentry *ecryptfs_dentry = file->f_path.dentry; |
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/* Private value of ecryptfs_dentry allocated in |
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* ecryptfs_lookup() */ |
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struct ecryptfs_file_info *file_info; |
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struct file *lower_file; |
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/* Released in ecryptfs_release or end of function if failure */ |
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file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL); |
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ecryptfs_set_file_private(file, file_info); |
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if (unlikely(!file_info)) { |
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ecryptfs_printk(KERN_ERR, |
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"Error attempting to allocate memory\n"); |
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return -ENOMEM; |
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} |
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lower_file = dentry_open(ecryptfs_dentry_to_lower_path(ecryptfs_dentry), |
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file->f_flags, current_cred()); |
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if (IS_ERR(lower_file)) { |
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printk(KERN_ERR "%s: Error attempting to initialize " |
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"the lower file for the dentry with name " |
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"[%pd]; rc = [%ld]\n", __func__, |
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ecryptfs_dentry, PTR_ERR(lower_file)); |
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kmem_cache_free(ecryptfs_file_info_cache, file_info); |
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return PTR_ERR(lower_file); |
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} |
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ecryptfs_set_file_lower(file, lower_file); |
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return 0; |
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} |
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static int ecryptfs_flush(struct file *file, fl_owner_t td) |
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{ |
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struct file *lower_file = ecryptfs_file_to_lower(file); |
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if (lower_file->f_op->flush) { |
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filemap_write_and_wait(file->f_mapping); |
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return lower_file->f_op->flush(lower_file, td); |
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} |
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return 0; |
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} |
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static int ecryptfs_release(struct inode *inode, struct file *file) |
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{ |
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ecryptfs_put_lower_file(inode); |
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kmem_cache_free(ecryptfs_file_info_cache, |
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ecryptfs_file_to_private(file)); |
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return 0; |
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} |
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static int ecryptfs_dir_release(struct inode *inode, struct file *file) |
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{ |
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fput(ecryptfs_file_to_lower(file)); |
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kmem_cache_free(ecryptfs_file_info_cache, |
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ecryptfs_file_to_private(file)); |
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return 0; |
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} |
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static loff_t ecryptfs_dir_llseek(struct file *file, loff_t offset, int whence) |
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{ |
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return vfs_llseek(ecryptfs_file_to_lower(file), offset, whence); |
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} |
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static int |
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ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
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{ |
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int rc; |
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rc = file_write_and_wait(file); |
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if (rc) |
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return rc; |
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return vfs_fsync(ecryptfs_file_to_lower(file), datasync); |
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} |
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static int ecryptfs_fasync(int fd, struct file *file, int flag) |
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{ |
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int rc = 0; |
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struct file *lower_file = NULL; |
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lower_file = ecryptfs_file_to_lower(file); |
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if (lower_file->f_op->fasync) |
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rc = lower_file->f_op->fasync(fd, lower_file, flag); |
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return rc; |
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} |
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static long |
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ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
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{ |
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struct file *lower_file = ecryptfs_file_to_lower(file); |
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long rc = -ENOTTY; |
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if (!lower_file->f_op->unlocked_ioctl) |
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return rc; |
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switch (cmd) { |
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case FITRIM: |
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case FS_IOC_GETFLAGS: |
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case FS_IOC_SETFLAGS: |
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case FS_IOC_GETVERSION: |
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case FS_IOC_SETVERSION: |
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rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg); |
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fsstack_copy_attr_all(file_inode(file), file_inode(lower_file)); |
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return rc; |
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default: |
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return rc; |
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} |
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} |
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#ifdef CONFIG_COMPAT |
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static long |
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ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
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{ |
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struct file *lower_file = ecryptfs_file_to_lower(file); |
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long rc = -ENOIOCTLCMD; |
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if (!lower_file->f_op->compat_ioctl) |
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return rc; |
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switch (cmd) { |
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case FITRIM: |
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case FS_IOC32_GETFLAGS: |
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case FS_IOC32_SETFLAGS: |
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case FS_IOC32_GETVERSION: |
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case FS_IOC32_SETVERSION: |
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rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg); |
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fsstack_copy_attr_all(file_inode(file), file_inode(lower_file)); |
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return rc; |
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default: |
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return rc; |
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} |
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} |
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#endif |
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const struct file_operations ecryptfs_dir_fops = { |
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.iterate_shared = ecryptfs_readdir, |
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.read = generic_read_dir, |
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.unlocked_ioctl = ecryptfs_unlocked_ioctl, |
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#ifdef CONFIG_COMPAT |
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.compat_ioctl = ecryptfs_compat_ioctl, |
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#endif |
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.open = ecryptfs_dir_open, |
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.release = ecryptfs_dir_release, |
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.fsync = ecryptfs_fsync, |
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.llseek = ecryptfs_dir_llseek, |
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}; |
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const struct file_operations ecryptfs_main_fops = { |
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.llseek = generic_file_llseek, |
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.read_iter = ecryptfs_read_update_atime, |
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.write_iter = generic_file_write_iter, |
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.unlocked_ioctl = ecryptfs_unlocked_ioctl, |
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#ifdef CONFIG_COMPAT |
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.compat_ioctl = ecryptfs_compat_ioctl, |
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#endif |
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.mmap = ecryptfs_mmap, |
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.open = ecryptfs_open, |
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.flush = ecryptfs_flush, |
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.release = ecryptfs_release, |
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.fsync = ecryptfs_fsync, |
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.fasync = ecryptfs_fasync, |
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.splice_read = generic_file_splice_read, |
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};
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