1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * eCryptfs: Linux filesystem encryption layer
5 * Copyright (C) 1997-2004 Erez Zadok
6 * Copyright (C) 2001-2004 Stony Brook University
7 * Copyright (C) 2004-2007 International Business Machines Corp.
8 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
9 * Michael C. Thompson <mcthomps@us.ibm.com>
12 #include <linux/file.h>
13 #include <linux/poll.h>
14 #include <linux/slab.h>
15 #include <linux/mount.h>
16 #include <linux/pagemap.h>
17 #include <linux/security.h>
18 #include <linux/compat.h>
19 #include <linux/fs_stack.h>
20 #include "ecryptfs_kernel.h"
23 * ecryptfs_read_update_atime
25 * generic_file_read updates the atime of upper layer inode. But, it
26 * doesn't give us a chance to update the atime of the lower layer
27 * inode. This function is a wrapper to generic_file_read. It
28 * updates the atime of the lower level inode if generic_file_read
29 * returns without any errors. This is to be used only for file reads.
30 * The function to be used for directory reads is ecryptfs_read.
32 static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,
36 const struct path *path;
37 struct file *file = iocb->ki_filp;
39 rc = generic_file_read_iter(iocb, to);
41 path = ecryptfs_dentry_to_lower_path(file->f_path.dentry);
47 struct ecryptfs_getdents_callback {
48 struct dir_context ctx;
49 struct dir_context *caller;
50 struct super_block *sb;
55 /* Inspired by generic filldir in fs/readdir.c */
57 ecryptfs_filldir(struct dir_context *ctx, const char *lower_name,
58 int lower_namelen, loff_t offset, u64 ino, unsigned int d_type)
60 struct ecryptfs_getdents_callback *buf =
61 container_of(ctx, struct ecryptfs_getdents_callback, ctx);
67 buf->filldir_called++;
68 err = ecryptfs_decode_and_decrypt_filename(&name, &name_size,
73 ecryptfs_printk(KERN_DEBUG,
74 "%s: Error attempting to decode and decrypt filename [%s]; rc = [%d]\n",
75 __func__, lower_name, err);
79 /* Mask -EINVAL errors as these are most likely due a plaintext
80 * filename present in the lower filesystem despite filename
81 * encryption being enabled. One unavoidable example would be
82 * the "lost+found" dentry in the root directory of an Ext4
88 buf->caller->pos = buf->ctx.pos;
89 res = dir_emit(buf->caller, name, name_size, ino, d_type);
92 buf->entries_written++;
98 * @file: The eCryptfs directory file
99 * @ctx: The actor to feed the entries to
101 static int ecryptfs_readdir(struct file *file, struct dir_context *ctx)
104 struct file *lower_file;
105 struct inode *inode = file_inode(file);
106 struct ecryptfs_getdents_callback buf = {
107 .ctx.actor = ecryptfs_filldir,
111 lower_file = ecryptfs_file_to_lower(file);
112 rc = iterate_dir(lower_file, &buf.ctx);
113 ctx->pos = buf.ctx.pos;
114 if (rc >= 0 && (buf.entries_written || !buf.filldir_called))
115 fsstack_copy_attr_atime(inode, file_inode(lower_file));
119 struct kmem_cache *ecryptfs_file_info_cache;
121 static int read_or_initialize_metadata(struct dentry *dentry)
123 struct inode *inode = d_inode(dentry);
124 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
125 struct ecryptfs_crypt_stat *crypt_stat;
128 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
129 mount_crypt_stat = &ecryptfs_superblock_to_private(
130 inode->i_sb)->mount_crypt_stat;
131 mutex_lock(&crypt_stat->cs_mutex);
133 if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED &&
134 crypt_stat->flags & ECRYPTFS_KEY_VALID) {
139 rc = ecryptfs_read_metadata(dentry);
143 if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) {
144 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
145 | ECRYPTFS_ENCRYPTED);
150 if (!(mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) &&
151 !i_size_read(ecryptfs_inode_to_lower(inode))) {
152 rc = ecryptfs_initialize_file(dentry, inode);
159 mutex_unlock(&crypt_stat->cs_mutex);
163 static int ecryptfs_mmap(struct file *file, struct vm_area_struct *vma)
165 struct file *lower_file = ecryptfs_file_to_lower(file);
167 * Don't allow mmap on top of file systems that don't support it
168 * natively. If FILESYSTEM_MAX_STACK_DEPTH > 2 or ecryptfs
169 * allows recursive mounting, this will need to be extended.
171 if (!lower_file->f_op->mmap)
173 return generic_file_mmap(file, vma);
178 * @inode: inode specifying file to open
179 * @file: Structure to return filled in
181 * Opens the file specified by inode.
183 * Returns zero on success; non-zero otherwise
185 static int ecryptfs_open(struct inode *inode, struct file *file)
188 struct ecryptfs_crypt_stat *crypt_stat = NULL;
189 struct dentry *ecryptfs_dentry = file->f_path.dentry;
190 /* Private value of ecryptfs_dentry allocated in
191 * ecryptfs_lookup() */
192 struct ecryptfs_file_info *file_info;
194 /* Released in ecryptfs_release or end of function if failure */
195 file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
196 ecryptfs_set_file_private(file, file_info);
198 ecryptfs_printk(KERN_ERR,
199 "Error attempting to allocate memory\n");
203 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
204 mutex_lock(&crypt_stat->cs_mutex);
205 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
206 ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
207 /* Policy code enabled in future release */
208 crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
209 | ECRYPTFS_ENCRYPTED);
211 mutex_unlock(&crypt_stat->cs_mutex);
212 rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
214 printk(KERN_ERR "%s: Error attempting to initialize "
215 "the lower file for the dentry with name "
216 "[%pd]; rc = [%d]\n", __func__,
217 ecryptfs_dentry, rc);
220 if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE)
221 == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) {
223 printk(KERN_WARNING "%s: Lower file is RO; eCryptfs "
224 "file must hence be opened RO\n", __func__);
227 ecryptfs_set_file_lower(
228 file, ecryptfs_inode_to_private(inode)->lower_file);
229 rc = read_or_initialize_metadata(ecryptfs_dentry);
232 ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = "
233 "[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino,
234 (unsigned long long)i_size_read(inode));
237 ecryptfs_put_lower_file(inode);
239 kmem_cache_free(ecryptfs_file_info_cache,
240 ecryptfs_file_to_private(file));
247 * @inode: inode specifying file to open
248 * @file: Structure to return filled in
250 * Opens the file specified by inode.
252 * Returns zero on success; non-zero otherwise
254 static int ecryptfs_dir_open(struct inode *inode, struct file *file)
256 struct dentry *ecryptfs_dentry = file->f_path.dentry;
257 /* Private value of ecryptfs_dentry allocated in
258 * ecryptfs_lookup() */
259 struct ecryptfs_file_info *file_info;
260 struct file *lower_file;
262 /* Released in ecryptfs_release or end of function if failure */
263 file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
264 ecryptfs_set_file_private(file, file_info);
265 if (unlikely(!file_info)) {
266 ecryptfs_printk(KERN_ERR,
267 "Error attempting to allocate memory\n");
270 lower_file = dentry_open(ecryptfs_dentry_to_lower_path(ecryptfs_dentry),
271 file->f_flags, current_cred());
272 if (IS_ERR(lower_file)) {
273 printk(KERN_ERR "%s: Error attempting to initialize "
274 "the lower file for the dentry with name "
275 "[%pd]; rc = [%ld]\n", __func__,
276 ecryptfs_dentry, PTR_ERR(lower_file));
277 kmem_cache_free(ecryptfs_file_info_cache, file_info);
278 return PTR_ERR(lower_file);
280 ecryptfs_set_file_lower(file, lower_file);
284 static int ecryptfs_flush(struct file *file, fl_owner_t td)
286 struct file *lower_file = ecryptfs_file_to_lower(file);
288 if (lower_file->f_op->flush) {
289 filemap_write_and_wait(file->f_mapping);
290 return lower_file->f_op->flush(lower_file, td);
296 static int ecryptfs_release(struct inode *inode, struct file *file)
298 ecryptfs_put_lower_file(inode);
299 kmem_cache_free(ecryptfs_file_info_cache,
300 ecryptfs_file_to_private(file));
304 static int ecryptfs_dir_release(struct inode *inode, struct file *file)
306 fput(ecryptfs_file_to_lower(file));
307 kmem_cache_free(ecryptfs_file_info_cache,
308 ecryptfs_file_to_private(file));
312 static loff_t ecryptfs_dir_llseek(struct file *file, loff_t offset, int whence)
314 return vfs_llseek(ecryptfs_file_to_lower(file), offset, whence);
318 ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
322 rc = file_write_and_wait(file);
326 return vfs_fsync(ecryptfs_file_to_lower(file), datasync);
329 static int ecryptfs_fasync(int fd, struct file *file, int flag)
332 struct file *lower_file = NULL;
334 lower_file = ecryptfs_file_to_lower(file);
335 if (lower_file->f_op->fasync)
336 rc = lower_file->f_op->fasync(fd, lower_file, flag);
341 ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
343 struct file *lower_file = ecryptfs_file_to_lower(file);
346 if (!lower_file->f_op->unlocked_ioctl)
351 case FS_IOC_GETFLAGS:
352 case FS_IOC_SETFLAGS:
353 case FS_IOC_GETVERSION:
354 case FS_IOC_SETVERSION:
355 rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
356 fsstack_copy_attr_all(file_inode(file), file_inode(lower_file));
366 ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
368 struct file *lower_file = ecryptfs_file_to_lower(file);
369 long rc = -ENOIOCTLCMD;
371 if (!lower_file->f_op->compat_ioctl)
376 case FS_IOC32_GETFLAGS:
377 case FS_IOC32_SETFLAGS:
378 case FS_IOC32_GETVERSION:
379 case FS_IOC32_SETVERSION:
380 rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
381 fsstack_copy_attr_all(file_inode(file), file_inode(lower_file));
390 const struct file_operations ecryptfs_dir_fops = {
391 .iterate_shared = ecryptfs_readdir,
392 .read = generic_read_dir,
393 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
395 .compat_ioctl = ecryptfs_compat_ioctl,
397 .open = ecryptfs_dir_open,
398 .release = ecryptfs_dir_release,
399 .fsync = ecryptfs_fsync,
400 .llseek = ecryptfs_dir_llseek,
403 const struct file_operations ecryptfs_main_fops = {
404 .llseek = generic_file_llseek,
405 .read_iter = ecryptfs_read_update_atime,
406 .write_iter = generic_file_write_iter,
407 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
409 .compat_ioctl = ecryptfs_compat_ioctl,
411 .mmap = ecryptfs_mmap,
412 .open = ecryptfs_open,
413 .flush = ecryptfs_flush,
414 .release = ecryptfs_release,
415 .fsync = ecryptfs_fsync,
416 .fasync = ecryptfs_fasync,
417 .splice_read = generic_file_splice_read,