inode.c 30.3 KB
Newer Older
1 2 3 4 5
/**
 * eCryptfs: Linux filesystem encryption layer
 *
 * Copyright (C) 1997-2004 Erez Zadok
 * Copyright (C) 2001-2004 Stony Brook University
6
 * Copyright (C) 2004-2007 International Business Machines Corp.
7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
 *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
 *              Michael C. Thompsion <mcthomps@us.ibm.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 */

#include <linux/file.h>
#include <linux/vmalloc.h>
#include <linux/pagemap.h>
#include <linux/dcache.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/crypto.h>
33
#include <linux/fs_stack.h>
34 35 36 37 38 39 40
#include "ecryptfs_kernel.h"

static struct dentry *lock_parent(struct dentry *dentry)
{
	struct dentry *dir;

	dir = dget(dentry->d_parent);
41
	mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT);
42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79
	return dir;
}

static void unlock_parent(struct dentry *dentry)
{
	mutex_unlock(&(dentry->d_parent->d_inode->i_mutex));
	dput(dentry->d_parent);
}

static void unlock_dir(struct dentry *dir)
{
	mutex_unlock(&dir->d_inode->i_mutex);
	dput(dir);
}

/**
 * ecryptfs_create_underlying_file
 * @lower_dir_inode: inode of the parent in the lower fs of the new file
 * @lower_dentry: New file's dentry in the lower fs
 * @ecryptfs_dentry: New file's dentry in ecryptfs
 * @mode: The mode of the new file
 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
 *
 * Creates the file in the lower file system.
 *
 * Returns zero on success; non-zero on error condition
 */
static int
ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
				struct dentry *dentry, int mode,
				struct nameidata *nd)
{
	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
	struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
	struct dentry *dentry_save;
	struct vfsmount *vfsmount_save;
	int rc;

80 81 82 83
	dentry_save = nd->path.dentry;
	vfsmount_save = nd->path.mnt;
	nd->path.dentry = lower_dentry;
	nd->path.mnt = lower_mnt;
84
	rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
85 86
	nd->path.dentry = dentry_save;
	nd->path.mnt = vfsmount_save;
87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121
	return rc;
}

/**
 * ecryptfs_do_create
 * @directory_inode: inode of the new file's dentry's parent in ecryptfs
 * @ecryptfs_dentry: New file's dentry in ecryptfs
 * @mode: The mode of the new file
 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
 *
 * Creates the underlying file and the eCryptfs inode which will link to
 * it. It will also update the eCryptfs directory inode to mimic the
 * stat of the lower directory inode.
 *
 * Returns zero on success; non-zero on error condition
 */
static int
ecryptfs_do_create(struct inode *directory_inode,
		   struct dentry *ecryptfs_dentry, int mode,
		   struct nameidata *nd)
{
	int rc;
	struct dentry *lower_dentry;
	struct dentry *lower_dir_dentry;

	lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
	lower_dir_dentry = lock_parent(lower_dentry);
	if (unlikely(IS_ERR(lower_dir_dentry))) {
		ecryptfs_printk(KERN_ERR, "Error locking directory of "
				"dentry\n");
		rc = PTR_ERR(lower_dir_dentry);
		goto out;
	}
	rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
					     ecryptfs_dentry, mode, nd);
122
	if (rc) {
123 124 125
		printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
		       "rc = [%d]\n", __FUNCTION__, rc);
		goto out_lock;
126 127 128 129 130 131 132
	}
	rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
				directory_inode->i_sb, 0);
	if (rc) {
		ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
		goto out_lock;
	}
133 134
	fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
	fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
135 136 137 138 139 140 141 142
out_lock:
	unlock_dir(lower_dir_dentry);
out:
	return rc;
}

/**
 * grow_file
143
 * @ecryptfs_dentry: the eCryptfs dentry
144 145 146
 *
 * This is the code which will grow the file to its correct size.
 */
147
static int grow_file(struct dentry *ecryptfs_dentry)
148
{
149
	struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
150 151
	struct file fake_file;
	struct ecryptfs_file_info tmp_file_info;
152 153
	char zero_virt[] = { 0x00 };
	int rc = 0;
154 155

	memset(&fake_file, 0, sizeof(fake_file));
156
	fake_file.f_path.dentry = ecryptfs_dentry;
157 158
	memset(&tmp_file_info, 0, sizeof(tmp_file_info));
	ecryptfs_set_file_private(&fake_file, &tmp_file_info);
159 160 161 162 163 164 165 166
	ecryptfs_set_file_lower(
		&fake_file,
		ecryptfs_inode_to_private(ecryptfs_inode)->lower_file);
	rc = ecryptfs_write(&fake_file, zero_virt, 0, 1);
	i_size_write(ecryptfs_inode, 0);
	rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
	ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |=
		ECRYPTFS_NEW_FILE;
167 168 169 170 171 172 173 174 175 176 177 178 179
	return rc;
}

/**
 * ecryptfs_initialize_file
 *
 * Cause the file to be changed from a basic empty file to an ecryptfs
 * file with a header and first data page.
 *
 * Returns zero on success
 */
static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
{
180 181
	struct ecryptfs_crypt_stat *crypt_stat =
		&ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
182 183 184 185
	int rc = 0;

	if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
		ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
186
		crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
187
		goto out;
188
	}
189
	crypt_stat->flags |= ECRYPTFS_NEW_FILE;
190 191 192
	ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
	rc = ecryptfs_new_file_context(ecryptfs_dentry);
	if (rc) {
193 194 195
		ecryptfs_printk(KERN_ERR, "Error creating new file "
				"context; rc = [%d]\n", rc);
		goto out;
196
	}
197
	rc = ecryptfs_write_metadata(ecryptfs_dentry);
198
	if (rc) {
199 200
		printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
		goto out;
201
	}
202
	rc = grow_file(ecryptfs_dentry);
203
	if (rc)
204
		printk(KERN_ERR "Error growing file; rc = [%d]\n", rc);
205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225
out:
	return rc;
}

/**
 * ecryptfs_create
 * @dir: The inode of the directory in which to create the file.
 * @dentry: The eCryptfs dentry
 * @mode: The mode of the new file.
 * @nd: nameidata
 *
 * Creates a new file.
 *
 * Returns zero on success; non-zero on error condition
 */
static int
ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
		int mode, struct nameidata *nd)
{
	int rc;

226 227
	/* ecryptfs_do_create() calls ecryptfs_interpose(), which opens
	 * the crypt_stat->lower_file (persistent file) */
228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257
	rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
	if (unlikely(rc)) {
		ecryptfs_printk(KERN_WARNING, "Failed to create file in"
				"lower filesystem\n");
		goto out;
	}
	/* At this point, a file exists on "disk"; we need to make sure
	 * that this on disk file is prepared to be an ecryptfs file */
	rc = ecryptfs_initialize_file(ecryptfs_dentry);
out:
	return rc;
}

/**
 * ecryptfs_lookup
 * @dir: inode
 * @dentry: The dentry
 * @nd: nameidata, may be NULL
 *
 * Find a file on disk. If the file does not exist, then we'll add it to the
 * dentry cache and continue on to read it from the disk.
 */
static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
				      struct nameidata *nd)
{
	int rc = 0;
	struct dentry *lower_dir_dentry;
	struct dentry *lower_dentry;
	struct vfsmount *lower_mnt;
	char *encoded_name;
258
	int encoded_namelen;
259
	struct ecryptfs_crypt_stat *crypt_stat = NULL;
260
	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
261 262 263 264 265 266 267
	char *page_virt = NULL;
	struct inode *lower_inode;
	u64 file_size;

	lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
	dentry->d_op = &ecryptfs_dops;
	if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
268 269 270 271 272
	    || (dentry->d_name.len == 2
		&& !strcmp(dentry->d_name.name, ".."))) {
		d_drop(dentry);
		goto out;
	}
273 274 275 276 277 278
	encoded_namelen = ecryptfs_encode_filename(crypt_stat,
						   dentry->d_name.name,
						   dentry->d_name.len,
						   &encoded_name);
	if (encoded_namelen < 0) {
		rc = encoded_namelen;
279 280
		d_drop(dentry);
		goto out;
281 282 283 284 285 286 287 288 289
	}
	ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
			"= [%d]\n", encoded_name, encoded_namelen);
	lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
				      encoded_namelen - 1);
	kfree(encoded_name);
	if (IS_ERR(lower_dentry)) {
		ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
		rc = PTR_ERR(lower_dentry);
290 291
		d_drop(dentry);
		goto out;
292
	}
293
	lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
294 295 296 297
	ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
       		"d_name.name = [%s]\n", lower_dentry,
		lower_dentry->d_name.name);
	lower_inode = lower_dentry->d_inode;
298
	fsstack_copy_attr_atime(dir, lower_dir_dentry->d_inode);
299 300 301
	BUG_ON(!atomic_read(&lower_dentry->d_count));
	ecryptfs_set_dentry_private(dentry,
				    kmem_cache_alloc(ecryptfs_dentry_info_cache,
302
						     GFP_KERNEL));
303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328
	if (!ecryptfs_dentry_to_private(dentry)) {
		rc = -ENOMEM;
		ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
				"to allocate ecryptfs_dentry_info struct\n");
		goto out_dput;
	}
	ecryptfs_set_dentry_lower(dentry, lower_dentry);
	ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
	if (!lower_dentry->d_inode) {
		/* We want to add because we couldn't find in lower */
		d_add(dentry, NULL);
		goto out;
	}
	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
	if (rc) {
		ecryptfs_printk(KERN_ERR, "Error interposing\n");
		goto out_dput;
	}
	if (S_ISDIR(lower_inode->i_mode)) {
		ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
		goto out;
	}
	if (S_ISLNK(lower_inode->i_mode)) {
		ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
		goto out;
	}
329 330 331 332
	if (special_file(lower_inode->i_mode)) {
		ecryptfs_printk(KERN_DEBUG, "Is a special file; returning\n");
		goto out;
	}
333 334 335 336 337 338
	if (!nd) {
		ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
				"as we *think* we are about to unlink\n");
		goto out;
	}
	/* Released in this function */
339
	page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
340
				      GFP_USER);
341 342 343 344 345 346 347
	if (!page_virt) {
		rc = -ENOMEM;
		ecryptfs_printk(KERN_ERR,
				"Cannot ecryptfs_kmalloc a page\n");
		goto out_dput;
	}
	crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
348
	if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
349
		ecryptfs_set_default_sizes(crypt_stat);
350 351
	rc = ecryptfs_read_and_validate_header_region(page_virt,
						      dentry->d_inode);
352
	if (rc) {
353 354 355 356 357 358
		rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
		if (rc) {
			printk(KERN_DEBUG "Valid metadata not found in header "
			       "region or xattr region; treating file as "
			       "unencrypted\n");
			rc = 0;
359 360 361
			kmem_cache_free(ecryptfs_header_cache_2, page_virt);
			goto out;
		}
362
		crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
363
	}
364 365 366 367
	mount_crypt_stat = &ecryptfs_superblock_to_private(
		dentry->d_sb)->mount_crypt_stat;
	if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
		if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
368
			file_size = (crypt_stat->num_header_bytes_at_front
369 370 371 372 373 374 375
				     + i_size_read(lower_dentry->d_inode));
		else
			file_size = i_size_read(lower_dentry->d_inode);
	} else {
		memcpy(&file_size, page_virt, sizeof(file_size));
		file_size = be64_to_cpu(file_size);
	}
376
	i_size_write(dentry->d_inode, (loff_t)file_size);
377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408
	kmem_cache_free(ecryptfs_header_cache_2, page_virt);
	goto out;

out_dput:
	dput(lower_dentry);
	d_drop(dentry);
out:
	return ERR_PTR(rc);
}

static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
			 struct dentry *new_dentry)
{
	struct dentry *lower_old_dentry;
	struct dentry *lower_new_dentry;
	struct dentry *lower_dir_dentry;
	u64 file_size_save;
	int rc;

	file_size_save = i_size_read(old_dentry->d_inode);
	lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
	lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
	dget(lower_old_dentry);
	dget(lower_new_dentry);
	lower_dir_dentry = lock_parent(lower_new_dentry);
	rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
		      lower_new_dentry);
	if (rc || !lower_new_dentry->d_inode)
		goto out_lock;
	rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
	if (rc)
		goto out_lock;
409 410
	fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
	fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
411 412 413 414 415 416 417
	old_dentry->d_inode->i_nlink =
		ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
	i_size_write(new_dentry->d_inode, file_size_save);
out_lock:
	unlock_dir(lower_dir_dentry);
	dput(lower_new_dentry);
	dput(lower_old_dentry);
418
	d_drop(lower_old_dentry);
419 420
	d_drop(new_dentry);
	d_drop(old_dentry);
421 422 423 424 425 426 427 428 429 430 431 432
	return rc;
}

static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
{
	int rc = 0;
	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
	struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);

	lock_parent(lower_dentry);
	rc = vfs_unlink(lower_dir_inode, lower_dentry);
	if (rc) {
433
		printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
434 435
		goto out_unlock;
	}
436
	fsstack_copy_attr_times(dir, lower_dir_inode);
437 438 439
	dentry->d_inode->i_nlink =
		ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
	dentry->d_inode->i_ctime = dir->i_ctime;
440
	d_drop(dentry);
441 442 443 444 445 446 447 448 449 450 451 452 453
out_unlock:
	unlock_parent(lower_dentry);
	return rc;
}

static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
			    const char *symname)
{
	int rc;
	struct dentry *lower_dentry;
	struct dentry *lower_dir_dentry;
	umode_t mode;
	char *encoded_symname;
454
	int encoded_symlen;
455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475
	struct ecryptfs_crypt_stat *crypt_stat = NULL;

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	dget(lower_dentry);
	lower_dir_dentry = lock_parent(lower_dentry);
	mode = S_IALLUGO;
	encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
						  strlen(symname),
						  &encoded_symname);
	if (encoded_symlen < 0) {
		rc = encoded_symlen;
		goto out_lock;
	}
	rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
			 encoded_symname, mode);
	kfree(encoded_symname);
	if (rc || !lower_dentry->d_inode)
		goto out_lock;
	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
	if (rc)
		goto out_lock;
476 477
	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
	fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499
out_lock:
	unlock_dir(lower_dir_dentry);
	dput(lower_dentry);
	if (!dentry->d_inode)
		d_drop(dentry);
	return rc;
}

static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
	int rc;
	struct dentry *lower_dentry;
	struct dentry *lower_dir_dentry;

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	lower_dir_dentry = lock_parent(lower_dentry);
	rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
	if (rc || !lower_dentry->d_inode)
		goto out;
	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
	if (rc)
		goto out;
500 501
	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
	fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
502 503 504 505 506 507 508 509 510 511 512 513
	dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
out:
	unlock_dir(lower_dir_dentry);
	if (!dentry->d_inode)
		d_drop(dentry);
	return rc;
}

static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
{
	struct dentry *lower_dentry;
	struct dentry *lower_dir_dentry;
514
	int rc;
515 516

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
517
	dget(dentry);
518
	lower_dir_dentry = lock_parent(lower_dentry);
519
	dget(lower_dentry);
520
	rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
521 522 523
	dput(lower_dentry);
	if (!rc)
		d_delete(lower_dentry);
524
	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
525 526 527 528
	dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
	unlock_dir(lower_dir_dentry);
	if (!rc)
		d_drop(dentry);
529
	dput(dentry);
530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547
	return rc;
}

static int
ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
{
	int rc;
	struct dentry *lower_dentry;
	struct dentry *lower_dir_dentry;

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	lower_dir_dentry = lock_parent(lower_dentry);
	rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
	if (rc || !lower_dentry->d_inode)
		goto out;
	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
	if (rc)
		goto out;
548 549
	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
	fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577
out:
	unlock_dir(lower_dir_dentry);
	if (!dentry->d_inode)
		d_drop(dentry);
	return rc;
}

static int
ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
		struct inode *new_dir, struct dentry *new_dentry)
{
	int rc;
	struct dentry *lower_old_dentry;
	struct dentry *lower_new_dentry;
	struct dentry *lower_old_dir_dentry;
	struct dentry *lower_new_dir_dentry;

	lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
	lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
	dget(lower_old_dentry);
	dget(lower_new_dentry);
	lower_old_dir_dentry = dget_parent(lower_old_dentry);
	lower_new_dir_dentry = dget_parent(lower_new_dentry);
	lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
	rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
			lower_new_dir_dentry->d_inode, lower_new_dentry);
	if (rc)
		goto out_lock;
578
	fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
579
	if (new_dir != old_dir)
580
		fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
581 582
out_lock:
	unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
583 584
	dput(lower_new_dentry->d_parent);
	dput(lower_old_dentry->d_parent);
585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635
	dput(lower_new_dentry);
	dput(lower_old_dentry);
	return rc;
}

static int
ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
{
	int rc;
	struct dentry *lower_dentry;
	char *decoded_name;
	char *lower_buf;
	mm_segment_t old_fs;
	struct ecryptfs_crypt_stat *crypt_stat;

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	if (!lower_dentry->d_inode->i_op ||
	    !lower_dentry->d_inode->i_op->readlink) {
		rc = -EINVAL;
		goto out;
	}
	/* Released in this function */
	lower_buf = kmalloc(bufsiz, GFP_KERNEL);
	if (lower_buf == NULL) {
		ecryptfs_printk(KERN_ERR, "Out of memory\n");
		rc = -ENOMEM;
		goto out;
	}
	old_fs = get_fs();
	set_fs(get_ds());
	ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
			"lower_dentry->d_name.name = [%s]\n",
			lower_dentry->d_name.name);
	rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
						   (char __user *)lower_buf,
						   bufsiz);
	set_fs(old_fs);
	if (rc >= 0) {
		crypt_stat = NULL;
		rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
					      &decoded_name);
		if (rc == -ENOMEM)
			goto out_free_lower_buf;
		if (rc > 0) {
			ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
					"to userspace: [%*s]\n", rc,
					decoded_name);
			if (copy_to_user(buf, decoded_name, rc))
				rc = -EFAULT;
		}
		kfree(decoded_name);
636 637
		fsstack_copy_attr_atime(dentry->d_inode,
					lower_dentry->d_inode);
638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686
	}
out_free_lower_buf:
	kfree(lower_buf);
out:
	return rc;
}

static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
{
	char *buf;
	int len = PAGE_SIZE, rc;
	mm_segment_t old_fs;

	/* Released in ecryptfs_put_link(); only release here on error */
	buf = kmalloc(len, GFP_KERNEL);
	if (!buf) {
		rc = -ENOMEM;
		goto out;
	}
	old_fs = get_fs();
	set_fs(get_ds());
	ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
			"dentry->d_name.name = [%s]\n", dentry->d_name.name);
	rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
	buf[rc] = '\0';
	set_fs(old_fs);
	if (rc < 0)
		goto out_free;
	rc = 0;
	nd_set_link(nd, buf);
	goto out;
out_free:
	kfree(buf);
out:
	return ERR_PTR(rc);
}

static void
ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
{
	/* Free the char* */
	kfree(nd_get_link(nd));
}

/**
 * upper_size_to_lower_size
 * @crypt_stat: Crypt_stat associated with file
 * @upper_size: Size of the upper file
 *
687
 * Calculate the required size of the lower file based on the
688 689 690 691 692 693 694 695 696 697 698
 * specified size of the upper file. This calculation is based on the
 * number of headers in the underlying file and the extent size.
 *
 * Returns Calculated size of the lower file.
 */
static loff_t
upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
			 loff_t upper_size)
{
	loff_t lower_size;

699
	lower_size = crypt_stat->num_header_bytes_at_front;
700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727
	if (upper_size != 0) {
		loff_t num_extents;

		num_extents = upper_size >> crypt_stat->extent_shift;
		if (upper_size & ~crypt_stat->extent_mask)
			num_extents++;
		lower_size += (num_extents * crypt_stat->extent_size);
	}
	return lower_size;
}

/**
 * ecryptfs_truncate
 * @dentry: The ecryptfs layer dentry
 * @new_length: The length to expand the file to
 *
 * Function to handle truncations modifying the size of the file. Note
 * that the file sizes are interpolated. When expanding, we are simply
 * writing strings of 0's out. When truncating, we need to modify the
 * underlying file size according to the page index interpolations.
 *
 * Returns zero on success; non-zero otherwise
 */
int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
{
	int rc = 0;
	struct inode *inode = dentry->d_inode;
	struct dentry *lower_dentry;
728
	struct file fake_ecryptfs_file;
729 730 731 732 733 734 735 736 737 738 739 740
	struct ecryptfs_crypt_stat *crypt_stat;
	loff_t i_size = i_size_read(inode);
	loff_t lower_size_before_truncate;
	loff_t lower_size_after_truncate;

	if (unlikely((new_length == i_size)))
		goto out;
	crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
	/* Set up a fake ecryptfs file, this is used to interface with
	 * the file in the underlying filesystem so that the
	 * truncation has an effect there as well. */
	memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
741
	fake_ecryptfs_file.f_path.dentry = dentry;
742 743 744
	/* Released at out_free: label */
	ecryptfs_set_file_private(&fake_ecryptfs_file,
				  kmem_cache_alloc(ecryptfs_file_info_cache,
745
						   GFP_KERNEL));
746 747 748 749 750
	if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
		rc = -ENOMEM;
		goto out;
	}
	lower_dentry = ecryptfs_dentry_to_lower(dentry);
751 752 753
	ecryptfs_set_file_lower(
		&fake_ecryptfs_file,
		ecryptfs_inode_to_private(dentry->d_inode)->lower_file);
754 755
	/* Switch on growing or shrinking file */
	if (new_length > i_size) {
756 757 758 759 760 761 762 763
		char zero[] = { 0x00 };

		/* Write a single 0 at the last position of the file;
		 * this triggers code that will fill in 0's throughout
		 * the intermediate portion of the previous end of the
		 * file and the new and of the file */
		rc = ecryptfs_write(&fake_ecryptfs_file, zero,
				    (new_length - 1), 1);
764
	} else { /* new_length < i_size_read(inode) */
765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782
		/* We're chopping off all the pages down do the page
		 * in which new_length is located. Fill in the end of
		 * that page from (new_length & ~PAGE_CACHE_MASK) to
		 * PAGE_CACHE_SIZE with zeros. */
		size_t num_zeros = (PAGE_CACHE_SIZE
				    - (new_length & ~PAGE_CACHE_MASK));

		if (num_zeros) {
			char *zeros_virt;

			zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
			if (!zeros_virt) {
				rc = -ENOMEM;
				goto out_free;
			}
			rc = ecryptfs_write(&fake_ecryptfs_file, zeros_virt,
					    new_length, num_zeros);
			kfree(zeros_virt);
783
			if (rc) {
784 785 786
				printk(KERN_ERR "Error attempting to zero out "
				       "the remainder of the end page on "
				       "reducing truncate; rc = [%d]\n", rc);
787
				goto out_free;
788 789
			}
		}
790
		vmtruncate(inode, new_length);
791
		rc = ecryptfs_write_inode_size_to_metadata(inode);
792 793 794 795
		if (rc) {
			printk(KERN_ERR	"Problem with "
			       "ecryptfs_write_inode_size_to_metadata; "
			       "rc = [%d]\n", rc);
796
			goto out_free;
797
		}
798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821
		/* We are reducing the size of the ecryptfs file, and need to
		 * know if we need to reduce the size of the lower file. */
		lower_size_before_truncate =
		    upper_size_to_lower_size(crypt_stat, i_size);
		lower_size_after_truncate =
		    upper_size_to_lower_size(crypt_stat, new_length);
		if (lower_size_after_truncate < lower_size_before_truncate)
			vmtruncate(lower_dentry->d_inode,
				   lower_size_after_truncate);
	}
out_free:
	if (ecryptfs_file_to_private(&fake_ecryptfs_file))
		kmem_cache_free(ecryptfs_file_info_cache,
				ecryptfs_file_to_private(&fake_ecryptfs_file));
out:
	return rc;
}

static int
ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
{
	int rc;

        if (nd) {
822 823
		struct vfsmount *vfsmnt_save = nd->path.mnt;
		struct dentry *dentry_save = nd->path.dentry;
824

825 826
		nd->path.mnt = ecryptfs_dentry_to_lower_mnt(nd->path.dentry);
		nd->path.dentry = ecryptfs_dentry_to_lower(nd->path.dentry);
827
		rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
828 829
		nd->path.mnt = vfsmnt_save;
		nd->path.dentry = dentry_save;
830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855
        } else
		rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
        return rc;
}

/**
 * ecryptfs_setattr
 * @dentry: dentry handle to the inode to modify
 * @ia: Structure with flags of what to change and values
 *
 * Updates the metadata of an inode. If the update is to the size
 * i.e. truncation, then ecryptfs_truncate will handle the size modification
 * of both the ecryptfs inode and the lower inode.
 *
 * All other metadata changes will be passed right to the lower filesystem,
 * and we will just update our inode to look like the lower.
 */
static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
{
	int rc = 0;
	struct dentry *lower_dentry;
	struct inode *inode;
	struct inode *lower_inode;
	struct ecryptfs_crypt_stat *crypt_stat;

	crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
856 857
	if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
		ecryptfs_init_crypt_stat(crypt_stat);
858 859
	inode = dentry->d_inode;
	lower_inode = ecryptfs_inode_to_lower(inode);
860 861 862 863
	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	mutex_lock(&crypt_stat->cs_mutex);
	if (S_ISDIR(dentry->d_inode->i_mode))
		crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
864 865 866
	else if (S_ISREG(dentry->d_inode->i_mode)
		 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
		     || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
867 868 869 870
		struct ecryptfs_mount_crypt_stat *mount_crypt_stat;

		mount_crypt_stat = &ecryptfs_superblock_to_private(
			dentry->d_sb)->mount_crypt_stat;
871
		rc = ecryptfs_read_metadata(dentry);
872
		if (rc) {
873 874 875
			if (!(mount_crypt_stat->flags
			      & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
				rc = -EIO;
876
				printk(KERN_WARNING "Either the lower file "
877
				       "is not in a valid eCryptfs format, "
878 879
				       "or the key could not be retrieved. "
				       "Plaintext passthrough mode is not "
880 881 882 883 884 885 886 887 888 889 890
				       "enabled; returning -EIO\n");
				mutex_unlock(&crypt_stat->cs_mutex);
				goto out;
			}
			rc = 0;
			crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
			mutex_unlock(&crypt_stat->cs_mutex);
			goto out;
		}
	}
	mutex_unlock(&crypt_stat->cs_mutex);
891 892 893 894 895 896 897 898 899 900 901 902
	if (ia->ia_valid & ATTR_SIZE) {
		ecryptfs_printk(KERN_DEBUG,
				"ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
				ia->ia_valid, ATTR_SIZE);
		rc = ecryptfs_truncate(dentry, ia->ia_size);
		/* ecryptfs_truncate handles resizing of the lower file */
		ia->ia_valid &= ~ATTR_SIZE;
		ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
				ia->ia_valid);
		if (rc < 0)
			goto out;
	}
903 904 905 906 907 908 909 910

	/*
	 * mode change is for clearing setuid/setgid bits. Allow lower fs
	 * to interpret this in its own way.
	 */
	if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
		ia->ia_valid &= ~ATTR_MODE;

911 912
	rc = notify_change(lower_dentry, ia);
out:
913
	fsstack_copy_attr_all(inode, lower_inode, NULL);
914 915 916
	return rc;
}

917
int
918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936
ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
		  size_t size, int flags)
{
	int rc = 0;
	struct dentry *lower_dentry;

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	if (!lower_dentry->d_inode->i_op->setxattr) {
		rc = -ENOSYS;
		goto out;
	}
	mutex_lock(&lower_dentry->d_inode->i_mutex);
	rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
						   size, flags);
	mutex_unlock(&lower_dentry->d_inode->i_mutex);
out:
	return rc;
}

937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954
ssize_t
ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
			void *value, size_t size)
{
	int rc = 0;

	if (!lower_dentry->d_inode->i_op->getxattr) {
		rc = -ENOSYS;
		goto out;
	}
	mutex_lock(&lower_dentry->d_inode->i_mutex);
	rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
						   size);
	mutex_unlock(&lower_dentry->d_inode->i_mutex);
out:
	return rc;
}

Adrian Bunk's avatar
Adrian Bunk committed
955
static ssize_t
956 957 958
ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
		  size_t size)
{
959 960
	return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
				       value, size);
961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012
}

static ssize_t
ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
{
	int rc = 0;
	struct dentry *lower_dentry;

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	if (!lower_dentry->d_inode->i_op->listxattr) {
		rc = -ENOSYS;
		goto out;
	}
	mutex_lock(&lower_dentry->d_inode->i_mutex);
	rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
	mutex_unlock(&lower_dentry->d_inode->i_mutex);
out:
	return rc;
}

static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
{
	int rc = 0;
	struct dentry *lower_dentry;

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	if (!lower_dentry->d_inode->i_op->removexattr) {
		rc = -ENOSYS;
		goto out;
	}
	mutex_lock(&lower_dentry->d_inode->i_mutex);
	rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
	mutex_unlock(&lower_dentry->d_inode->i_mutex);
out:
	return rc;
}

int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
{
	if ((ecryptfs_inode_to_lower(inode)
	     == (struct inode *)candidate_lower_inode))
		return 1;
	else
		return 0;
}

int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
{
	ecryptfs_init_inode(inode, (struct inode *)lower_inode);
	return 0;
}

1013
const struct inode_operations ecryptfs_symlink_iops = {
1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024
	.readlink = ecryptfs_readlink,
	.follow_link = ecryptfs_follow_link,
	.put_link = ecryptfs_put_link,
	.permission = ecryptfs_permission,
	.setattr = ecryptfs_setattr,
	.setxattr = ecryptfs_setxattr,
	.getxattr = ecryptfs_getxattr,
	.listxattr = ecryptfs_listxattr,
	.removexattr = ecryptfs_removexattr
};

1025
const struct inode_operations ecryptfs_dir_iops = {
1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042
	.create = ecryptfs_create,
	.lookup = ecryptfs_lookup,
	.link = ecryptfs_link,
	.unlink = ecryptfs_unlink,
	.symlink = ecryptfs_symlink,
	.mkdir = ecryptfs_mkdir,
	.rmdir = ecryptfs_rmdir,
	.mknod = ecryptfs_mknod,
	.rename = ecryptfs_rename,
	.permission = ecryptfs_permission,
	.setattr = ecryptfs_setattr,
	.setxattr = ecryptfs_setxattr,
	.getxattr = ecryptfs_getxattr,
	.listxattr = ecryptfs_listxattr,
	.removexattr = ecryptfs_removexattr
};

1043
const struct inode_operations ecryptfs_main_iops = {
1044 1045 1046 1047 1048 1049 1050
	.permission = ecryptfs_permission,
	.setattr = ecryptfs_setattr,
	.setxattr = ecryptfs_setxattr,
	.getxattr = ecryptfs_getxattr,
	.listxattr = ecryptfs_listxattr,
	.removexattr = ecryptfs_removexattr
};