| 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/aio.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 | */ |
| 47 | static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb, |
| 48 | const struct iovec *iov, |
| 49 | unsigned long nr_segs, loff_t pos) |
| 50 | { |
| 51 | ssize_t rc; |
| 52 | struct path lower; |
| 53 | struct file *file = iocb->ki_filp; |
| 54 | |
| 55 | rc = generic_file_aio_read(iocb, iov, nr_segs, pos); |
| 56 | /* |
| 57 | * Even though this is a async interface, we need to wait |
| 58 | * for IO to finish to update atime |
| 59 | */ |
| 60 | if (-EIOCBQUEUED == rc) |
| 61 | rc = wait_on_sync_kiocb(iocb); |
| 62 | if (rc >= 0) { |
| 63 | lower.dentry = ecryptfs_dentry_to_lower(file->f_path.dentry); |
| 64 | lower.mnt = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry); |
| 65 | touch_atime(&lower); |
| 66 | } |
| 67 | return rc; |
| 68 | } |
| 69 | |
| 70 | struct ecryptfs_getdents_callback { |
| 71 | struct dir_context ctx; |
| 72 | struct dir_context *caller; |
| 73 | struct dentry *dentry; |
| 74 | int filldir_called; |
| 75 | int entries_written; |
| 76 | }; |
| 77 | |
| 78 | /* Inspired by generic filldir in fs/readdir.c */ |
| 79 | static int |
| 80 | ecryptfs_filldir(void *dirent, const char *lower_name, int lower_namelen, |
| 81 | loff_t offset, u64 ino, unsigned int d_type) |
| 82 | { |
| 83 | struct ecryptfs_getdents_callback *buf = |
| 84 | (struct ecryptfs_getdents_callback *)dirent; |
| 85 | size_t name_size; |
| 86 | char *name; |
| 87 | int rc; |
| 88 | |
| 89 | buf->filldir_called++; |
| 90 | rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size, |
| 91 | buf->dentry, lower_name, |
| 92 | lower_namelen); |
| 93 | if (rc) { |
| 94 | printk(KERN_ERR "%s: Error attempting to decode and decrypt " |
| 95 | "filename [%s]; rc = [%d]\n", __func__, lower_name, |
| 96 | rc); |
| 97 | goto out; |
| 98 | } |
| 99 | buf->caller->pos = buf->ctx.pos; |
| 100 | rc = !dir_emit(buf->caller, name, name_size, ino, d_type); |
| 101 | kfree(name); |
| 102 | if (!rc) |
| 103 | buf->entries_written++; |
| 104 | out: |
| 105 | return rc; |
| 106 | } |
| 107 | |
| 108 | /** |
| 109 | * ecryptfs_readdir |
| 110 | * @file: The eCryptfs directory file |
| 111 | * @ctx: The actor to feed the entries to |
| 112 | */ |
| 113 | static int ecryptfs_readdir(struct file *file, struct dir_context *ctx) |
| 114 | { |
| 115 | int rc; |
| 116 | struct file *lower_file; |
| 117 | struct inode *inode; |
| 118 | struct ecryptfs_getdents_callback buf = { |
| 119 | .ctx.actor = ecryptfs_filldir, |
| 120 | .caller = ctx, |
| 121 | .dentry = file->f_path.dentry |
| 122 | }; |
| 123 | lower_file = ecryptfs_file_to_lower(file); |
| 124 | lower_file->f_pos = ctx->pos; |
| 125 | inode = file_inode(file); |
| 126 | rc = iterate_dir(lower_file, &buf.ctx); |
| 127 | ctx->pos = buf.ctx.pos; |
| 128 | if (rc < 0) |
| 129 | goto out; |
| 130 | if (buf.filldir_called && !buf.entries_written) |
| 131 | goto out; |
| 132 | if (rc >= 0) |
| 133 | fsstack_copy_attr_atime(inode, |
| 134 | file_inode(lower_file)); |
| 135 | out: |
| 136 | return rc; |
| 137 | } |
| 138 | |
| 139 | struct kmem_cache *ecryptfs_file_info_cache; |
| 140 | |
| 141 | static int read_or_initialize_metadata(struct dentry *dentry) |
| 142 | { |
| 143 | struct inode *inode = dentry->d_inode; |
| 144 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat; |
| 145 | struct ecryptfs_crypt_stat *crypt_stat; |
| 146 | int rc; |
| 147 | |
| 148 | crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; |
| 149 | mount_crypt_stat = &ecryptfs_superblock_to_private( |
| 150 | inode->i_sb)->mount_crypt_stat; |
| 151 | mutex_lock(&crypt_stat->cs_mutex); |
| 152 | |
| 153 | if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED && |
| 154 | crypt_stat->flags & ECRYPTFS_KEY_VALID) { |
| 155 | rc = 0; |
| 156 | goto out; |
| 157 | } |
| 158 | |
| 159 | rc = ecryptfs_read_metadata(dentry); |
| 160 | if (!rc) |
| 161 | goto out; |
| 162 | |
| 163 | if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) { |
| 164 | crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED |
| 165 | | ECRYPTFS_ENCRYPTED); |
| 166 | rc = 0; |
| 167 | goto out; |
| 168 | } |
| 169 | |
| 170 | if (!(mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) && |
| 171 | !i_size_read(ecryptfs_inode_to_lower(inode))) { |
| 172 | rc = ecryptfs_initialize_file(dentry, inode); |
| 173 | if (!rc) |
| 174 | goto out; |
| 175 | } |
| 176 | |
| 177 | rc = -EIO; |
| 178 | out: |
| 179 | mutex_unlock(&crypt_stat->cs_mutex); |
| 180 | return rc; |
| 181 | } |
| 182 | |
| 183 | /** |
| 184 | * ecryptfs_open |
| 185 | * @inode: inode speciying file to open |
| 186 | * @file: Structure to return filled in |
| 187 | * |
| 188 | * Opens the file specified by inode. |
| 189 | * |
| 190 | * Returns zero on success; non-zero otherwise |
| 191 | */ |
| 192 | static int ecryptfs_open(struct inode *inode, struct file *file) |
| 193 | { |
| 194 | int rc = 0; |
| 195 | struct ecryptfs_crypt_stat *crypt_stat = NULL; |
| 196 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat; |
| 197 | struct dentry *ecryptfs_dentry = file->f_path.dentry; |
| 198 | /* Private value of ecryptfs_dentry allocated in |
| 199 | * ecryptfs_lookup() */ |
| 200 | struct ecryptfs_file_info *file_info; |
| 201 | |
| 202 | mount_crypt_stat = &ecryptfs_superblock_to_private( |
| 203 | ecryptfs_dentry->d_sb)->mount_crypt_stat; |
| 204 | if ((mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) |
| 205 | && ((file->f_flags & O_WRONLY) || (file->f_flags & O_RDWR) |
| 206 | || (file->f_flags & O_CREAT) || (file->f_flags & O_TRUNC) |
| 207 | || (file->f_flags & O_APPEND))) { |
| 208 | printk(KERN_WARNING "Mount has encrypted view enabled; " |
| 209 | "files may only be read\n"); |
| 210 | rc = -EPERM; |
| 211 | goto out; |
| 212 | } |
| 213 | /* Released in ecryptfs_release or end of function if failure */ |
| 214 | file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL); |
| 215 | ecryptfs_set_file_private(file, file_info); |
| 216 | if (!file_info) { |
| 217 | ecryptfs_printk(KERN_ERR, |
| 218 | "Error attempting to allocate memory\n"); |
| 219 | rc = -ENOMEM; |
| 220 | goto out; |
| 221 | } |
| 222 | crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; |
| 223 | mutex_lock(&crypt_stat->cs_mutex); |
| 224 | if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) { |
| 225 | ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n"); |
| 226 | /* Policy code enabled in future release */ |
| 227 | crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED |
| 228 | | ECRYPTFS_ENCRYPTED); |
| 229 | } |
| 230 | mutex_unlock(&crypt_stat->cs_mutex); |
| 231 | rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode); |
| 232 | if (rc) { |
| 233 | printk(KERN_ERR "%s: Error attempting to initialize " |
| 234 | "the lower file for the dentry with name " |
| 235 | "[%s]; rc = [%d]\n", __func__, |
| 236 | ecryptfs_dentry->d_name.name, rc); |
| 237 | goto out_free; |
| 238 | } |
| 239 | if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE) |
| 240 | == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) { |
| 241 | rc = -EPERM; |
| 242 | printk(KERN_WARNING "%s: Lower file is RO; eCryptfs " |
| 243 | "file must hence be opened RO\n", __func__); |
| 244 | goto out_put; |
| 245 | } |
| 246 | ecryptfs_set_file_lower( |
| 247 | file, ecryptfs_inode_to_private(inode)->lower_file); |
| 248 | if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) { |
| 249 | ecryptfs_printk(KERN_DEBUG, "This is a directory\n"); |
| 250 | mutex_lock(&crypt_stat->cs_mutex); |
| 251 | crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); |
| 252 | mutex_unlock(&crypt_stat->cs_mutex); |
| 253 | rc = 0; |
| 254 | goto out; |
| 255 | } |
| 256 | rc = read_or_initialize_metadata(ecryptfs_dentry); |
| 257 | if (rc) |
| 258 | goto out_put; |
| 259 | ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = " |
| 260 | "[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino, |
| 261 | (unsigned long long)i_size_read(inode)); |
| 262 | goto out; |
| 263 | out_put: |
| 264 | ecryptfs_put_lower_file(inode); |
| 265 | out_free: |
| 266 | kmem_cache_free(ecryptfs_file_info_cache, |
| 267 | ecryptfs_file_to_private(file)); |
| 268 | out: |
| 269 | return rc; |
| 270 | } |
| 271 | |
| 272 | static int ecryptfs_flush(struct file *file, fl_owner_t td) |
| 273 | { |
| 274 | struct file *lower_file = ecryptfs_file_to_lower(file); |
| 275 | |
| 276 | if (lower_file->f_op && lower_file->f_op->flush) { |
| 277 | filemap_write_and_wait(file->f_mapping); |
| 278 | return lower_file->f_op->flush(lower_file, td); |
| 279 | } |
| 280 | |
| 281 | return 0; |
| 282 | } |
| 283 | |
| 284 | static int ecryptfs_release(struct inode *inode, struct file *file) |
| 285 | { |
| 286 | ecryptfs_put_lower_file(inode); |
| 287 | kmem_cache_free(ecryptfs_file_info_cache, |
| 288 | ecryptfs_file_to_private(file)); |
| 289 | return 0; |
| 290 | } |
| 291 | |
| 292 | static int |
| 293 | ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
| 294 | { |
| 295 | int rc; |
| 296 | |
| 297 | rc = filemap_write_and_wait(file->f_mapping); |
| 298 | if (rc) |
| 299 | return rc; |
| 300 | |
| 301 | return vfs_fsync(ecryptfs_file_to_lower(file), datasync); |
| 302 | } |
| 303 | |
| 304 | static int ecryptfs_fasync(int fd, struct file *file, int flag) |
| 305 | { |
| 306 | int rc = 0; |
| 307 | struct file *lower_file = NULL; |
| 308 | |
| 309 | lower_file = ecryptfs_file_to_lower(file); |
| 310 | if (lower_file->f_op && lower_file->f_op->fasync) |
| 311 | rc = lower_file->f_op->fasync(fd, lower_file, flag); |
| 312 | return rc; |
| 313 | } |
| 314 | |
| 315 | static long |
| 316 | ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
| 317 | { |
| 318 | struct file *lower_file = NULL; |
| 319 | long rc = -ENOTTY; |
| 320 | |
| 321 | if (ecryptfs_file_to_private(file)) |
| 322 | lower_file = ecryptfs_file_to_lower(file); |
| 323 | if (lower_file && lower_file->f_op && lower_file->f_op->unlocked_ioctl) |
| 324 | rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg); |
| 325 | return rc; |
| 326 | } |
| 327 | |
| 328 | #ifdef CONFIG_COMPAT |
| 329 | static long |
| 330 | ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
| 331 | { |
| 332 | struct file *lower_file = NULL; |
| 333 | long rc = -ENOIOCTLCMD; |
| 334 | |
| 335 | if (ecryptfs_file_to_private(file)) |
| 336 | lower_file = ecryptfs_file_to_lower(file); |
| 337 | if (lower_file && lower_file->f_op && lower_file->f_op->compat_ioctl) |
| 338 | rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg); |
| 339 | return rc; |
| 340 | } |
| 341 | #endif |
| 342 | |
| 343 | const struct file_operations ecryptfs_dir_fops = { |
| 344 | .iterate = ecryptfs_readdir, |
| 345 | .read = generic_read_dir, |
| 346 | .unlocked_ioctl = ecryptfs_unlocked_ioctl, |
| 347 | #ifdef CONFIG_COMPAT |
| 348 | .compat_ioctl = ecryptfs_compat_ioctl, |
| 349 | #endif |
| 350 | .open = ecryptfs_open, |
| 351 | .flush = ecryptfs_flush, |
| 352 | .release = ecryptfs_release, |
| 353 | .fsync = ecryptfs_fsync, |
| 354 | .fasync = ecryptfs_fasync, |
| 355 | .splice_read = generic_file_splice_read, |
| 356 | .llseek = default_llseek, |
| 357 | }; |
| 358 | |
| 359 | const struct file_operations ecryptfs_main_fops = { |
| 360 | .llseek = generic_file_llseek, |
| 361 | .read = do_sync_read, |
| 362 | .aio_read = ecryptfs_read_update_atime, |
| 363 | .write = do_sync_write, |
| 364 | .aio_write = generic_file_aio_write, |
| 365 | .iterate = ecryptfs_readdir, |
| 366 | .unlocked_ioctl = ecryptfs_unlocked_ioctl, |
| 367 | #ifdef CONFIG_COMPAT |
| 368 | .compat_ioctl = ecryptfs_compat_ioctl, |
| 369 | #endif |
| 370 | .mmap = generic_file_mmap, |
| 371 | .open = ecryptfs_open, |
| 372 | .flush = ecryptfs_flush, |
| 373 | .release = ecryptfs_release, |
| 374 | .fsync = ecryptfs_fsync, |
| 375 | .fasync = ecryptfs_fasync, |
| 376 | .splice_read = generic_file_splice_read, |
| 377 | }; |