Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 1 | /** |
| 2 | * eCryptfs: Linux filesystem encryption layer |
| 3 | * |
| 4 | * Copyright (C) 2007 International Business Machines Corp. |
| 5 | * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com> |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU General Public License as |
| 9 | * published by the Free Software Foundation; either version 2 of the |
| 10 | * License, or (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, but |
| 13 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 15 | * General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License |
| 18 | * along with this program; if not, write to the Free Software |
| 19 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA |
| 20 | * 02111-1307, USA. |
| 21 | */ |
| 22 | |
| 23 | #include <linux/fs.h> |
| 24 | #include <linux/pagemap.h> |
| 25 | #include "ecryptfs_kernel.h" |
| 26 | |
| 27 | /** |
| 28 | * ecryptfs_write_lower |
| 29 | * @ecryptfs_inode: The eCryptfs inode |
| 30 | * @data: Data to write |
| 31 | * @offset: Byte offset in the lower file to which to write the data |
| 32 | * @size: Number of bytes from @data to write at @offset in the lower |
| 33 | * file |
| 34 | * |
| 35 | * Write data to the lower file. |
| 36 | * |
Tyler Hicks | 96a7b9c | 2009-09-16 19:04:20 -0500 | [diff] [blame] | 37 | * Returns bytes written on success; less than zero on error |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 38 | */ |
| 39 | int ecryptfs_write_lower(struct inode *ecryptfs_inode, char *data, |
| 40 | loff_t offset, size_t size) |
| 41 | { |
Tyler Hicks | f61500e | 2011-08-04 22:58:51 -0500 | [diff] [blame] | 42 | struct file *lower_file; |
Tyler Hicks | 96a7b9c | 2009-09-16 19:04:20 -0500 | [diff] [blame] | 43 | ssize_t rc; |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 44 | |
Tyler Hicks | f61500e | 2011-08-04 22:58:51 -0500 | [diff] [blame] | 45 | lower_file = ecryptfs_inode_to_private(ecryptfs_inode)->lower_file; |
| 46 | if (!lower_file) |
| 47 | return -EIO; |
Al Viro | 7bb307e | 2013-02-23 14:51:48 -0500 | [diff] [blame] | 48 | rc = kernel_write(lower_file, data, size, offset); |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 49 | mark_inode_dirty_sync(ecryptfs_inode); |
| 50 | return rc; |
| 51 | } |
| 52 | |
| 53 | /** |
| 54 | * ecryptfs_write_lower_page_segment |
| 55 | * @ecryptfs_inode: The eCryptfs inode |
| 56 | * @page_for_lower: The page containing the data to be written to the |
| 57 | * lower file |
| 58 | * @offset_in_page: The offset in the @page_for_lower from which to |
| 59 | * start writing the data |
| 60 | * @size: The amount of data from @page_for_lower to write to the |
| 61 | * lower file |
| 62 | * |
| 63 | * Determines the byte offset in the file for the given page and |
| 64 | * offset within the page, maps the page, and makes the call to write |
| 65 | * the contents of @page_for_lower to the lower inode. |
| 66 | * |
| 67 | * Returns zero on success; non-zero otherwise |
| 68 | */ |
| 69 | int ecryptfs_write_lower_page_segment(struct inode *ecryptfs_inode, |
| 70 | struct page *page_for_lower, |
| 71 | size_t offset_in_page, size_t size) |
| 72 | { |
| 73 | char *virt; |
| 74 | loff_t offset; |
| 75 | int rc; |
| 76 | |
Michael Halcrow | 8a146a2 | 2007-11-14 16:58:27 -0800 | [diff] [blame] | 77 | offset = ((((loff_t)page_for_lower->index) << PAGE_CACHE_SHIFT) |
Michael Halcrow | d6a13c1 | 2007-10-16 01:28:12 -0700 | [diff] [blame] | 78 | + offset_in_page); |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 79 | virt = kmap(page_for_lower); |
| 80 | rc = ecryptfs_write_lower(ecryptfs_inode, virt, offset, size); |
Tyler Hicks | 96a7b9c | 2009-09-16 19:04:20 -0500 | [diff] [blame] | 81 | if (rc > 0) |
| 82 | rc = 0; |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 83 | kunmap(page_for_lower); |
| 84 | return rc; |
| 85 | } |
| 86 | |
| 87 | /** |
| 88 | * ecryptfs_write |
Al Viro | 48c1e44 | 2010-05-21 11:09:58 -0400 | [diff] [blame] | 89 | * @ecryptfs_inode: The eCryptfs file into which to write |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 90 | * @data: Virtual address where data to write is located |
| 91 | * @offset: Offset in the eCryptfs file at which to begin writing the |
| 92 | * data from @data |
| 93 | * @size: The number of bytes to write from @data |
| 94 | * |
| 95 | * Write an arbitrary amount of data to an arbitrary location in the |
| 96 | * eCryptfs inode page cache. This is done on a page-by-page, and then |
| 97 | * by an extent-by-extent, basis; individual extents are encrypted and |
| 98 | * written to the lower page cache (via VFS writes). This function |
| 99 | * takes care of all the address translation to locations in the lower |
| 100 | * filesystem; it also handles truncate events, writing out zeros |
| 101 | * where necessary. |
| 102 | * |
| 103 | * Returns zero on success; non-zero otherwise |
| 104 | */ |
Al Viro | 48c1e44 | 2010-05-21 11:09:58 -0400 | [diff] [blame] | 105 | int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset, |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 106 | size_t size) |
| 107 | { |
| 108 | struct page *ecryptfs_page; |
Tyler Hicks | 13a791b | 2009-04-13 15:29:27 -0500 | [diff] [blame] | 109 | struct ecryptfs_crypt_stat *crypt_stat; |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 110 | char *ecryptfs_page_virt; |
Tyler Hicks | 13a791b | 2009-04-13 15:29:27 -0500 | [diff] [blame] | 111 | loff_t ecryptfs_file_size = i_size_read(ecryptfs_inode); |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 112 | loff_t data_offset = 0; |
| 113 | loff_t pos; |
| 114 | int rc = 0; |
| 115 | |
Tyler Hicks | 13a791b | 2009-04-13 15:29:27 -0500 | [diff] [blame] | 116 | crypt_stat = &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; |
Eric Sandeen | 7a3f595 | 2007-12-17 16:20:10 -0800 | [diff] [blame] | 117 | /* |
| 118 | * if we are writing beyond current size, then start pos |
| 119 | * at the current size - we'll fill in zeros from there. |
| 120 | */ |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 121 | if (offset > ecryptfs_file_size) |
| 122 | pos = ecryptfs_file_size; |
| 123 | else |
| 124 | pos = offset; |
| 125 | while (pos < (offset + size)) { |
| 126 | pgoff_t ecryptfs_page_idx = (pos >> PAGE_CACHE_SHIFT); |
| 127 | size_t start_offset_in_page = (pos & ~PAGE_CACHE_MASK); |
| 128 | size_t num_bytes = (PAGE_CACHE_SIZE - start_offset_in_page); |
Li Wang | 684a3ff | 2012-01-19 09:44:36 +0800 | [diff] [blame] | 129 | loff_t total_remaining_bytes = ((offset + size) - pos); |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 130 | |
Tyler Hicks | 5e6f0d7 | 2012-01-18 18:30:04 -0600 | [diff] [blame] | 131 | if (fatal_signal_pending(current)) { |
| 132 | rc = -EINTR; |
| 133 | break; |
| 134 | } |
| 135 | |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 136 | if (num_bytes > total_remaining_bytes) |
| 137 | num_bytes = total_remaining_bytes; |
| 138 | if (pos < offset) { |
Eric Sandeen | 7a3f595 | 2007-12-17 16:20:10 -0800 | [diff] [blame] | 139 | /* remaining zeros to write, up to destination offset */ |
Li Wang | 684a3ff | 2012-01-19 09:44:36 +0800 | [diff] [blame] | 140 | loff_t total_remaining_zeros = (offset - pos); |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 141 | |
| 142 | if (num_bytes > total_remaining_zeros) |
| 143 | num_bytes = total_remaining_zeros; |
| 144 | } |
Al Viro | 02bd979 | 2010-05-21 11:02:14 -0400 | [diff] [blame] | 145 | ecryptfs_page = ecryptfs_get_locked_page(ecryptfs_inode, |
Michael Halcrow | 16a72c4 | 2007-10-16 01:28:14 -0700 | [diff] [blame] | 146 | ecryptfs_page_idx); |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 147 | if (IS_ERR(ecryptfs_page)) { |
| 148 | rc = PTR_ERR(ecryptfs_page); |
| 149 | printk(KERN_ERR "%s: Error getting page at " |
| 150 | "index [%ld] from eCryptfs inode " |
Harvey Harrison | 18d1dbf | 2008-04-29 00:59:48 -0700 | [diff] [blame] | 151 | "mapping; rc = [%d]\n", __func__, |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 152 | ecryptfs_page_idx, rc); |
| 153 | goto out; |
| 154 | } |
Cong Wang | 465c934 | 2012-02-10 13:39:50 +0800 | [diff] [blame] | 155 | ecryptfs_page_virt = kmap_atomic(ecryptfs_page); |
Eric Sandeen | 7a3f595 | 2007-12-17 16:20:10 -0800 | [diff] [blame] | 156 | |
| 157 | /* |
| 158 | * pos: where we're now writing, offset: where the request was |
| 159 | * If current pos is before request, we are filling zeros |
| 160 | * If we are at or beyond request, we are writing the *data* |
| 161 | * If we're in a fresh page beyond eof, zero it in either case |
| 162 | */ |
| 163 | if (pos < offset || !start_offset_in_page) { |
| 164 | /* We are extending past the previous end of the file. |
| 165 | * Fill in zero values to the end of the page */ |
| 166 | memset(((char *)ecryptfs_page_virt |
| 167 | + start_offset_in_page), 0, |
| 168 | PAGE_CACHE_SIZE - start_offset_in_page); |
| 169 | } |
| 170 | |
| 171 | /* pos >= offset, we are now writing the data request */ |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 172 | if (pos >= offset) { |
| 173 | memcpy(((char *)ecryptfs_page_virt |
| 174 | + start_offset_in_page), |
| 175 | (data + data_offset), num_bytes); |
| 176 | data_offset += num_bytes; |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 177 | } |
Cong Wang | 465c934 | 2012-02-10 13:39:50 +0800 | [diff] [blame] | 178 | kunmap_atomic(ecryptfs_page_virt); |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 179 | flush_dcache_page(ecryptfs_page); |
Michael Halcrow | 16a72c4 | 2007-10-16 01:28:14 -0700 | [diff] [blame] | 180 | SetPageUptodate(ecryptfs_page); |
| 181 | unlock_page(ecryptfs_page); |
Tyler Hicks | 13a791b | 2009-04-13 15:29:27 -0500 | [diff] [blame] | 182 | if (crypt_stat->flags & ECRYPTFS_ENCRYPTED) |
| 183 | rc = ecryptfs_encrypt_page(ecryptfs_page); |
| 184 | else |
| 185 | rc = ecryptfs_write_lower_page_segment(ecryptfs_inode, |
| 186 | ecryptfs_page, |
| 187 | start_offset_in_page, |
| 188 | data_offset); |
Michael Halcrow | 16a72c4 | 2007-10-16 01:28:14 -0700 | [diff] [blame] | 189 | page_cache_release(ecryptfs_page); |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 190 | if (rc) { |
| 191 | printk(KERN_ERR "%s: Error encrypting " |
Harvey Harrison | 18d1dbf | 2008-04-29 00:59:48 -0700 | [diff] [blame] | 192 | "page; rc = [%d]\n", __func__, rc); |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 193 | goto out; |
| 194 | } |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 195 | pos += num_bytes; |
| 196 | } |
Tyler Hicks | 5e6f0d7 | 2012-01-18 18:30:04 -0600 | [diff] [blame] | 197 | if (pos > ecryptfs_file_size) { |
| 198 | i_size_write(ecryptfs_inode, pos); |
Tyler Hicks | 13a791b | 2009-04-13 15:29:27 -0500 | [diff] [blame] | 199 | if (crypt_stat->flags & ECRYPTFS_ENCRYPTED) { |
Tyler Hicks | 5e6f0d7 | 2012-01-18 18:30:04 -0600 | [diff] [blame] | 200 | int rc2; |
| 201 | |
| 202 | rc2 = ecryptfs_write_inode_size_to_metadata( |
Tyler Hicks | 13a791b | 2009-04-13 15:29:27 -0500 | [diff] [blame] | 203 | ecryptfs_inode); |
Tyler Hicks | 5e6f0d7 | 2012-01-18 18:30:04 -0600 | [diff] [blame] | 204 | if (rc2) { |
Tyler Hicks | 13a791b | 2009-04-13 15:29:27 -0500 | [diff] [blame] | 205 | printk(KERN_ERR "Problem with " |
| 206 | "ecryptfs_write_inode_size_to_metadata; " |
Tyler Hicks | 5e6f0d7 | 2012-01-18 18:30:04 -0600 | [diff] [blame] | 207 | "rc = [%d]\n", rc2); |
| 208 | if (!rc) |
| 209 | rc = rc2; |
Tyler Hicks | 13a791b | 2009-04-13 15:29:27 -0500 | [diff] [blame] | 210 | goto out; |
| 211 | } |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 212 | } |
| 213 | } |
| 214 | out: |
| 215 | return rc; |
| 216 | } |
| 217 | |
| 218 | /** |
| 219 | * ecryptfs_read_lower |
| 220 | * @data: The read data is stored here by this function |
| 221 | * @offset: Byte offset in the lower file from which to read the data |
| 222 | * @size: Number of bytes to read from @offset of the lower file and |
| 223 | * store into @data |
| 224 | * @ecryptfs_inode: The eCryptfs inode |
| 225 | * |
| 226 | * Read @size bytes of data at byte offset @offset from the lower |
| 227 | * inode into memory location @data. |
| 228 | * |
Tyler Hicks | 96a7b9c | 2009-09-16 19:04:20 -0500 | [diff] [blame] | 229 | * Returns bytes read on success; 0 on EOF; less than zero on error |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 230 | */ |
| 231 | int ecryptfs_read_lower(char *data, loff_t offset, size_t size, |
| 232 | struct inode *ecryptfs_inode) |
| 233 | { |
Tyler Hicks | f61500e | 2011-08-04 22:58:51 -0500 | [diff] [blame] | 234 | struct file *lower_file; |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 235 | mm_segment_t fs_save; |
Tyler Hicks | 96a7b9c | 2009-09-16 19:04:20 -0500 | [diff] [blame] | 236 | ssize_t rc; |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 237 | |
Tyler Hicks | f61500e | 2011-08-04 22:58:51 -0500 | [diff] [blame] | 238 | lower_file = ecryptfs_inode_to_private(ecryptfs_inode)->lower_file; |
| 239 | if (!lower_file) |
| 240 | return -EIO; |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 241 | fs_save = get_fs(); |
| 242 | set_fs(get_ds()); |
Tyler Hicks | f61500e | 2011-08-04 22:58:51 -0500 | [diff] [blame] | 243 | rc = vfs_read(lower_file, data, size, &offset); |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 244 | set_fs(fs_save); |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 245 | return rc; |
| 246 | } |
| 247 | |
| 248 | /** |
| 249 | * ecryptfs_read_lower_page_segment |
| 250 | * @page_for_ecryptfs: The page into which data for eCryptfs will be |
| 251 | * written |
| 252 | * @offset_in_page: Offset in @page_for_ecryptfs from which to start |
| 253 | * writing |
| 254 | * @size: The number of bytes to write into @page_for_ecryptfs |
| 255 | * @ecryptfs_inode: The eCryptfs inode |
| 256 | * |
| 257 | * Determines the byte offset in the file for the given page and |
| 258 | * offset within the page, maps the page, and makes the call to read |
| 259 | * the contents of @page_for_ecryptfs from the lower inode. |
| 260 | * |
| 261 | * Returns zero on success; non-zero otherwise |
| 262 | */ |
| 263 | int ecryptfs_read_lower_page_segment(struct page *page_for_ecryptfs, |
| 264 | pgoff_t page_index, |
| 265 | size_t offset_in_page, size_t size, |
| 266 | struct inode *ecryptfs_inode) |
| 267 | { |
| 268 | char *virt; |
| 269 | loff_t offset; |
| 270 | int rc; |
| 271 | |
Michael Halcrow | d6a13c1 | 2007-10-16 01:28:12 -0700 | [diff] [blame] | 272 | offset = ((((loff_t)page_index) << PAGE_CACHE_SHIFT) + offset_in_page); |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 273 | virt = kmap(page_for_ecryptfs); |
| 274 | rc = ecryptfs_read_lower(virt, offset, size, ecryptfs_inode); |
Tyler Hicks | 96a7b9c | 2009-09-16 19:04:20 -0500 | [diff] [blame] | 275 | if (rc > 0) |
| 276 | rc = 0; |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 277 | kunmap(page_for_ecryptfs); |
Michael Halcrow | 16a72c4 | 2007-10-16 01:28:14 -0700 | [diff] [blame] | 278 | flush_dcache_page(page_for_ecryptfs); |
Michael Halcrow | da0102a | 2007-10-16 01:28:07 -0700 | [diff] [blame] | 279 | return rc; |
| 280 | } |