1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23#include <linux/fs.h>
24#include <linux/pagemap.h>
25#include "ecryptfs_kernel.h"
26
27
28
29
30
31
32
33
34
35
36
37
38
39int ecryptfs_write_lower(struct inode *ecryptfs_inode, char *data,
40 loff_t offset, size_t size)
41{
42 struct ecryptfs_inode_info *inode_info;
43 mm_segment_t fs_save;
44 ssize_t rc;
45
46 inode_info = ecryptfs_inode_to_private(ecryptfs_inode);
47 mutex_lock(&inode_info->lower_file_mutex);
48 BUG_ON(!inode_info->lower_file);
49 inode_info->lower_file->f_pos = offset;
50 fs_save = get_fs();
51 set_fs(get_ds());
52 rc = vfs_write(inode_info->lower_file, data, size,
53 &inode_info->lower_file->f_pos);
54 set_fs(fs_save);
55 mutex_unlock(&inode_info->lower_file_mutex);
56 mark_inode_dirty_sync(ecryptfs_inode);
57 return rc;
58}
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76int ecryptfs_write_lower_page_segment(struct inode *ecryptfs_inode,
77 struct page *page_for_lower,
78 size_t offset_in_page, size_t size)
79{
80 char *virt;
81 loff_t offset;
82 int rc;
83
84 offset = ((((loff_t)page_for_lower->index) << PAGE_CACHE_SHIFT)
85 + offset_in_page);
86 virt = kmap(page_for_lower);
87 rc = ecryptfs_write_lower(ecryptfs_inode, virt, offset, size);
88 if (rc > 0)
89 rc = 0;
90 kunmap(page_for_lower);
91 return rc;
92}
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112int ecryptfs_write(struct file *ecryptfs_file, char *data, loff_t offset,
113 size_t size)
114{
115 struct page *ecryptfs_page;
116 struct ecryptfs_crypt_stat *crypt_stat;
117 struct inode *ecryptfs_inode = ecryptfs_file->f_dentry->d_inode;
118 char *ecryptfs_page_virt;
119 loff_t ecryptfs_file_size = i_size_read(ecryptfs_inode);
120 loff_t data_offset = 0;
121 loff_t pos;
122 int rc = 0;
123
124 crypt_stat = &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
125
126
127
128
129 if (offset > ecryptfs_file_size)
130 pos = ecryptfs_file_size;
131 else
132 pos = offset;
133 while (pos < (offset + size)) {
134 pgoff_t ecryptfs_page_idx = (pos >> PAGE_CACHE_SHIFT);
135 size_t start_offset_in_page = (pos & ~PAGE_CACHE_MASK);
136 size_t num_bytes = (PAGE_CACHE_SIZE - start_offset_in_page);
137 size_t total_remaining_bytes = ((offset + size) - pos);
138
139 if (num_bytes > total_remaining_bytes)
140 num_bytes = total_remaining_bytes;
141 if (pos < offset) {
142
143 size_t total_remaining_zeros = (offset - pos);
144
145 if (num_bytes > total_remaining_zeros)
146 num_bytes = total_remaining_zeros;
147 }
148 ecryptfs_page = ecryptfs_get_locked_page(ecryptfs_file,
149 ecryptfs_page_idx);
150 if (IS_ERR(ecryptfs_page)) {
151 rc = PTR_ERR(ecryptfs_page);
152 printk(KERN_ERR "%s: Error getting page at "
153 "index [%ld] from eCryptfs inode "
154 "mapping; rc = [%d]\n", __func__,
155 ecryptfs_page_idx, rc);
156 goto out;
157 }
158 ecryptfs_page_virt = kmap_atomic(ecryptfs_page, KM_USER0);
159
160
161
162
163
164
165
166 if (pos < offset || !start_offset_in_page) {
167
168
169 memset(((char *)ecryptfs_page_virt
170 + start_offset_in_page), 0,
171 PAGE_CACHE_SIZE - start_offset_in_page);
172 }
173
174
175 if (pos >= offset) {
176 memcpy(((char *)ecryptfs_page_virt
177 + start_offset_in_page),
178 (data + data_offset), num_bytes);
179 data_offset += num_bytes;
180 }
181 kunmap_atomic(ecryptfs_page_virt, KM_USER0);
182 flush_dcache_page(ecryptfs_page);
183 SetPageUptodate(ecryptfs_page);
184 unlock_page(ecryptfs_page);
185 if (crypt_stat->flags & ECRYPTFS_ENCRYPTED)
186 rc = ecryptfs_encrypt_page(ecryptfs_page);
187 else
188 rc = ecryptfs_write_lower_page_segment(ecryptfs_inode,
189 ecryptfs_page,
190 start_offset_in_page,
191 data_offset);
192 page_cache_release(ecryptfs_page);
193 if (rc) {
194 printk(KERN_ERR "%s: Error encrypting "
195 "page; rc = [%d]\n", __func__, rc);
196 goto out;
197 }
198 pos += num_bytes;
199 }
200 if ((offset + size) > ecryptfs_file_size) {
201 i_size_write(ecryptfs_inode, (offset + size));
202 if (crypt_stat->flags & ECRYPTFS_ENCRYPTED) {
203 rc = ecryptfs_write_inode_size_to_metadata(
204 ecryptfs_inode);
205 if (rc) {
206 printk(KERN_ERR "Problem with "
207 "ecryptfs_write_inode_size_to_metadata; "
208 "rc = [%d]\n", rc);
209 goto out;
210 }
211 }
212 }
213out:
214 return rc;
215}
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230int ecryptfs_read_lower(char *data, loff_t offset, size_t size,
231 struct inode *ecryptfs_inode)
232{
233 struct ecryptfs_inode_info *inode_info =
234 ecryptfs_inode_to_private(ecryptfs_inode);
235 mm_segment_t fs_save;
236 ssize_t rc;
237
238 mutex_lock(&inode_info->lower_file_mutex);
239 BUG_ON(!inode_info->lower_file);
240 inode_info->lower_file->f_pos = offset;
241 fs_save = get_fs();
242 set_fs(get_ds());
243 rc = vfs_read(inode_info->lower_file, data, size,
244 &inode_info->lower_file->f_pos);
245 set_fs(fs_save);
246 mutex_unlock(&inode_info->lower_file_mutex);
247 return rc;
248}
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265int ecryptfs_read_lower_page_segment(struct page *page_for_ecryptfs,
266 pgoff_t page_index,
267 size_t offset_in_page, size_t size,
268 struct inode *ecryptfs_inode)
269{
270 char *virt;
271 loff_t offset;
272 int rc;
273
274 offset = ((((loff_t)page_index) << PAGE_CACHE_SHIFT) + offset_in_page);
275 virt = kmap(page_for_ecryptfs);
276 rc = ecryptfs_read_lower(virt, offset, size, ecryptfs_inode);
277 if (rc > 0)
278 rc = 0;
279 kunmap(page_for_ecryptfs);
280 flush_dcache_page(page_for_ecryptfs);
281 return rc;
282}
283
284#if 0
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302int ecryptfs_read(char *data, loff_t offset, size_t size,
303 struct file *ecryptfs_file)
304{
305 struct page *ecryptfs_page;
306 char *ecryptfs_page_virt;
307 loff_t ecryptfs_file_size =
308 i_size_read(ecryptfs_file->f_dentry->d_inode);
309 loff_t data_offset = 0;
310 loff_t pos;
311 int rc = 0;
312
313 if ((offset + size) > ecryptfs_file_size) {
314 rc = -EINVAL;
315 printk(KERN_ERR "%s: Attempt to read data past the end of the "
316 "file; offset = [%lld]; size = [%td]; "
317 "ecryptfs_file_size = [%lld]\n",
318 __func__, offset, size, ecryptfs_file_size);
319 goto out;
320 }
321 pos = offset;
322 while (pos < (offset + size)) {
323 pgoff_t ecryptfs_page_idx = (pos >> PAGE_CACHE_SHIFT);
324 size_t start_offset_in_page = (pos & ~PAGE_CACHE_MASK);
325 size_t num_bytes = (PAGE_CACHE_SIZE - start_offset_in_page);
326 size_t total_remaining_bytes = ((offset + size) - pos);
327
328 if (num_bytes > total_remaining_bytes)
329 num_bytes = total_remaining_bytes;
330 ecryptfs_page = ecryptfs_get_locked_page(ecryptfs_file,
331 ecryptfs_page_idx);
332 if (IS_ERR(ecryptfs_page)) {
333 rc = PTR_ERR(ecryptfs_page);
334 printk(KERN_ERR "%s: Error getting page at "
335 "index [%ld] from eCryptfs inode "
336 "mapping; rc = [%d]\n", __func__,
337 ecryptfs_page_idx, rc);
338 goto out;
339 }
340 ecryptfs_page_virt = kmap_atomic(ecryptfs_page, KM_USER0);
341 memcpy((data + data_offset),
342 ((char *)ecryptfs_page_virt + start_offset_in_page),
343 num_bytes);
344 kunmap_atomic(ecryptfs_page_virt, KM_USER0);
345 flush_dcache_page(ecryptfs_page);
346 SetPageUptodate(ecryptfs_page);
347 unlock_page(ecryptfs_page);
348 page_cache_release(ecryptfs_page);
349 pos += num_bytes;
350 data_offset += num_bytes;
351 }
352out:
353 return rc;
354}
355#endif
356