1/** 2 * eCryptfs: Linux filesystem encryption layer 3 * 4 * Copyright (C) 1997-2004 Erez Zadok 5 * Copyright (C) 2001-2004 Stony Brook University 6 * Copyright (C) 2004-2007 International Business Machines Corp. 7 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com> 8 * Michael C. Thompson <mcthomps@us.ibm.com> 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License as 12 * published by the Free Software Foundation; either version 2 of the 13 * License, or (at your option) any later version. 14 * 15 * This program is distributed in the hope that it will be useful, but 16 * WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 18 * General Public License for more details. 19 * 20 * You should have received a copy of the GNU General Public License 21 * along with this program; if not, write to the Free Software 22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 23 * 02111-1307, USA. 24 */ 25 26#include <linux/file.h> 27#include <linux/poll.h> 28#include <linux/slab.h> 29#include <linux/mount.h> 30#include <linux/pagemap.h> 31#include <linux/security.h> 32#include <linux/compat.h> 33#include <linux/fs_stack.h> 34#include <linux/smp_lock.h> 35#include "ecryptfs_kernel.h" 36 37/** 38 * ecryptfs_read_update_atime 39 * 40 * generic_file_read updates the atime of upper layer inode. But, it 41 * doesn't give us a chance to update the atime of the lower layer 42 * inode. This function is a wrapper to generic_file_read. It 43 * updates the atime of the lower level inode if generic_file_read 44 * returns without any errors. This is to be used only for file reads. 45 * The function to be used for directory reads is ecryptfs_read. 46 */ 47static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb, 48 const struct iovec *iov, 49 unsigned long nr_segs, loff_t pos) 50{ 51 int rc; 52 struct dentry *lower_dentry; 53 struct vfsmount *lower_vfsmount; 54 struct file *file = iocb->ki_filp; 55 56 rc = generic_file_aio_read(iocb, iov, nr_segs, pos); 57 /* 58 * Even though this is a async interface, we need to wait 59 * for IO to finish to update atime 60 */ 61 if (-EIOCBQUEUED == rc) 62 rc = wait_on_sync_kiocb(iocb); 63 if (rc >= 0) { 64 lower_dentry = ecryptfs_dentry_to_lower(file->f_path.dentry); 65 lower_vfsmount = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry); 66 touch_atime(lower_vfsmount, lower_dentry); 67 } 68 return rc; 69} 70 71struct ecryptfs_getdents_callback { 72 void *dirent; 73 struct dentry *dentry; 74 filldir_t filldir; 75 int filldir_called; 76 int entries_written; 77}; 78 79/* Inspired by generic filldir in fs/readdir.c */ 80static int 81ecryptfs_filldir(void *dirent, const char *lower_name, int lower_namelen, 82 loff_t offset, u64 ino, unsigned int d_type) 83{ 84 struct ecryptfs_getdents_callback *buf = 85 (struct ecryptfs_getdents_callback *)dirent; 86 size_t name_size; 87 char *name; 88 int rc; 89 90 buf->filldir_called++; 91 rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size, 92 buf->dentry, lower_name, 93 lower_namelen); 94 if (rc) { 95 printk(KERN_ERR "%s: Error attempting to decode and decrypt " 96 "filename [%s]; rc = [%d]\n", __func__, lower_name, 97 rc); 98 goto out; 99 } 100 rc = buf->filldir(buf->dirent, name, name_size, offset, ino, d_type); 101 kfree(name); 102 if (rc >= 0) 103 buf->entries_written++; 104out: 105 return rc; 106} 107 108/** 109 * ecryptfs_readdir 110 * @file: The eCryptfs directory file 111 * @dirent: Directory entry handle 112 * @filldir: The filldir callback function 113 */ 114static int ecryptfs_readdir(struct file *file, void *dirent, filldir_t filldir) 115{ 116 int rc; 117 struct file *lower_file; 118 struct inode *inode; 119 struct ecryptfs_getdents_callback buf; 120 121 lower_file = ecryptfs_file_to_lower(file); 122 lower_file->f_pos = file->f_pos; 123 inode = file->f_path.dentry->d_inode; 124 memset(&buf, 0, sizeof(buf)); 125 buf.dirent = dirent; 126 buf.dentry = file->f_path.dentry; 127 buf.filldir = filldir; 128 buf.filldir_called = 0; 129 buf.entries_written = 0; 130 rc = vfs_readdir(lower_file, ecryptfs_filldir, (void *)&buf); 131 file->f_pos = lower_file->f_pos; 132 if (rc < 0) 133 goto out; 134 if (buf.filldir_called && !buf.entries_written) 135 goto out; 136 if (rc >= 0) 137 fsstack_copy_attr_atime(inode, 138 lower_file->f_path.dentry->d_inode); 139out: 140 return rc; 141} 142 143struct kmem_cache *ecryptfs_file_info_cache; 144 145/** 146 * ecryptfs_open 147 * @inode: inode speciying file to open 148 * @file: Structure to return filled in 149 * 150 * Opens the file specified by inode. 151 * 152 * Returns zero on success; non-zero otherwise 153 */ 154static int ecryptfs_open(struct inode *inode, struct file *file) 155{ 156 int rc = 0; 157 struct ecryptfs_crypt_stat *crypt_stat = NULL; 158 struct ecryptfs_mount_crypt_stat *mount_crypt_stat; 159 struct dentry *ecryptfs_dentry = file->f_path.dentry; 160 /* Private value of ecryptfs_dentry allocated in 161 * ecryptfs_lookup() */ 162 struct dentry *lower_dentry; 163 struct ecryptfs_file_info *file_info; 164 165 mount_crypt_stat = &ecryptfs_superblock_to_private( 166 ecryptfs_dentry->d_sb)->mount_crypt_stat; 167 if ((mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) 168 && ((file->f_flags & O_WRONLY) || (file->f_flags & O_RDWR) 169 || (file->f_flags & O_CREAT) || (file->f_flags & O_TRUNC) 170 || (file->f_flags & O_APPEND))) { 171 printk(KERN_WARNING "Mount has encrypted view enabled; " 172 "files may only be read\n"); 173 rc = -EPERM; 174 goto out; 175 } 176 /* Released in ecryptfs_release or end of function if failure */ 177 file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL); 178 ecryptfs_set_file_private(file, file_info); 179 if (!file_info) { 180 ecryptfs_printk(KERN_ERR, 181 "Error attempting to allocate memory\n"); 182 rc = -ENOMEM; 183 goto out; 184 } 185 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); 186 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; 187 mutex_lock(&crypt_stat->cs_mutex); 188 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) { 189 ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n"); 190 /* Policy code enabled in future release */ 191 crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED 192 | ECRYPTFS_ENCRYPTED); 193 } 194 mutex_unlock(&crypt_stat->cs_mutex); 195 if (!ecryptfs_inode_to_private(inode)->lower_file) { 196 rc = ecryptfs_init_persistent_file(ecryptfs_dentry); 197 if (rc) { 198 printk(KERN_ERR "%s: Error attempting to initialize " 199 "the persistent file for the dentry with name " 200 "[%s]; rc = [%d]\n", __func__, 201 ecryptfs_dentry->d_name.name, rc); 202 goto out_free; 203 } 204 } 205 if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_RDONLY) 206 && !(file->f_flags & O_RDONLY)) { 207 rc = -EPERM; 208 printk(KERN_WARNING "%s: Lower persistent file is RO; eCryptfs " 209 "file must hence be opened RO\n", __func__); 210 goto out_free; 211 } 212 ecryptfs_set_file_lower( 213 file, ecryptfs_inode_to_private(inode)->lower_file); 214 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) { 215 ecryptfs_printk(KERN_DEBUG, "This is a directory\n"); 216 mutex_lock(&crypt_stat->cs_mutex); 217 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); 218 mutex_unlock(&crypt_stat->cs_mutex); 219 rc = 0; 220 goto out; 221 } 222 mutex_lock(&crypt_stat->cs_mutex); 223 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED) 224 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID)) { 225 rc = ecryptfs_read_metadata(ecryptfs_dentry); 226 if (rc) { 227 ecryptfs_printk(KERN_DEBUG, 228 "Valid headers not found\n"); 229 if (!(mount_crypt_stat->flags 230 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) { 231 rc = -EIO; 232 printk(KERN_WARNING "Either the lower file " 233 "is not in a valid eCryptfs format, " 234 "or the key could not be retrieved. " 235 "Plaintext passthrough mode is not " 236 "enabled; returning -EIO\n"); 237 mutex_unlock(&crypt_stat->cs_mutex); 238 goto out_free; 239 } 240 rc = 0; 241 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); 242 mutex_unlock(&crypt_stat->cs_mutex); 243 goto out; 244 } 245 } 246 mutex_unlock(&crypt_stat->cs_mutex); 247 ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = [0x%.16x] " 248 "size: [0x%.16x]\n", inode, inode->i_ino, 249 i_size_read(inode)); 250 goto out; 251out_free: 252 kmem_cache_free(ecryptfs_file_info_cache, 253 ecryptfs_file_to_private(file)); 254out: 255 return rc; 256} 257 258static int ecryptfs_flush(struct file *file, fl_owner_t td) 259{ 260 int rc = 0; 261 struct file *lower_file = NULL; 262 263 lower_file = ecryptfs_file_to_lower(file); 264 if (lower_file->f_op && lower_file->f_op->flush) 265 rc = lower_file->f_op->flush(lower_file, td); 266 return rc; 267} 268 269static int ecryptfs_release(struct inode *inode, struct file *file) 270{ 271 kmem_cache_free(ecryptfs_file_info_cache, 272 ecryptfs_file_to_private(file)); 273 return 0; 274} 275 276static int 277ecryptfs_fsync(struct file *file, int datasync) 278{ 279 return vfs_fsync(ecryptfs_file_to_lower(file), datasync); 280} 281 282static int ecryptfs_fasync(int fd, struct file *file, int flag) 283{ 284 int rc = 0; 285 struct file *lower_file = NULL; 286 287 lock_kernel(); 288 lower_file = ecryptfs_file_to_lower(file); 289 if (lower_file->f_op && lower_file->f_op->fasync) 290 rc = lower_file->f_op->fasync(fd, lower_file, flag); 291 unlock_kernel(); 292 return rc; 293} 294 295static long 296ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 297{ 298 struct file *lower_file = NULL; 299 long rc = -ENOTTY; 300 301 if (ecryptfs_file_to_private(file)) 302 lower_file = ecryptfs_file_to_lower(file); 303 if (lower_file && lower_file->f_op && lower_file->f_op->unlocked_ioctl) 304 rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg); 305 return rc; 306} 307 308#ifdef CONFIG_COMPAT 309static long 310ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 311{ 312 struct file *lower_file = NULL; 313 long rc = -ENOIOCTLCMD; 314 315 if (ecryptfs_file_to_private(file)) 316 lower_file = ecryptfs_file_to_lower(file); 317 if (lower_file && lower_file->f_op && lower_file->f_op->compat_ioctl) 318 rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg); 319 return rc; 320} 321#endif 322 323const struct file_operations ecryptfs_dir_fops = { 324 .readdir = ecryptfs_readdir, 325 .unlocked_ioctl = ecryptfs_unlocked_ioctl, 326#ifdef CONFIG_COMPAT 327 .compat_ioctl = ecryptfs_compat_ioctl, 328#endif 329 .open = ecryptfs_open, 330 .flush = ecryptfs_flush, 331 .release = ecryptfs_release, 332 .fsync = ecryptfs_fsync, 333 .fasync = ecryptfs_fasync, 334 .splice_read = generic_file_splice_read, 335}; 336 337const struct file_operations ecryptfs_main_fops = { 338 .llseek = generic_file_llseek, 339 .read = do_sync_read, 340 .aio_read = ecryptfs_read_update_atime, 341 .write = do_sync_write, 342 .aio_write = generic_file_aio_write, 343 .readdir = ecryptfs_readdir, 344 .unlocked_ioctl = ecryptfs_unlocked_ioctl, 345#ifdef CONFIG_COMPAT 346 .compat_ioctl = ecryptfs_compat_ioctl, 347#endif 348 .mmap = generic_file_mmap, 349 .open = ecryptfs_open, 350 .flush = ecryptfs_flush, 351 .release = ecryptfs_release, 352 .fsync = ecryptfs_fsync, 353 .fasync = ecryptfs_fasync, 354 .splice_read = generic_file_splice_read, 355}; 356