1 // SPDX-License-Identifier: MIT
2 /*
3 * VirtualBox Guest Shared Folders support: Utility functions.
4 * Mainly conversion from/to VirtualBox/Linux data structures.
5 *
6 * Copyright (C) 2006-2018 Oracle Corporation
7 */
8
9 #include <linux/namei.h>
10 #include <linux/nls.h>
11 #include <linux/sizes.h>
12 #include <linux/vfs.h>
13 #include "vfsmod.h"
14
vboxsf_new_inode(struct super_block * sb)15 struct inode *vboxsf_new_inode(struct super_block *sb)
16 {
17 struct vboxsf_sbi *sbi = VBOXSF_SBI(sb);
18 struct inode *inode;
19 unsigned long flags;
20 int cursor, ret;
21 u32 gen;
22
23 inode = new_inode(sb);
24 if (!inode)
25 return ERR_PTR(-ENOMEM);
26
27 idr_preload(GFP_KERNEL);
28 spin_lock_irqsave(&sbi->ino_idr_lock, flags);
29 cursor = idr_get_cursor(&sbi->ino_idr);
30 ret = idr_alloc_cyclic(&sbi->ino_idr, inode, 1, 0, GFP_ATOMIC);
31 if (ret >= 0 && ret < cursor)
32 sbi->next_generation++;
33 gen = sbi->next_generation;
34 spin_unlock_irqrestore(&sbi->ino_idr_lock, flags);
35 idr_preload_end();
36
37 if (ret < 0) {
38 iput(inode);
39 return ERR_PTR(ret);
40 }
41
42 inode->i_ino = ret;
43 inode->i_generation = gen;
44 return inode;
45 }
46
47 /* set [inode] attributes based on [info], uid/gid based on [sbi] */
vboxsf_init_inode(struct vboxsf_sbi * sbi,struct inode * inode,const struct shfl_fsobjinfo * info)48 void vboxsf_init_inode(struct vboxsf_sbi *sbi, struct inode *inode,
49 const struct shfl_fsobjinfo *info)
50 {
51 const struct shfl_fsobjattr *attr;
52 s64 allocated;
53 int mode;
54
55 attr = &info->attr;
56
57 #define mode_set(r) ((attr->mode & (SHFL_UNIX_##r)) ? (S_##r) : 0)
58
59 mode = mode_set(IRUSR);
60 mode |= mode_set(IWUSR);
61 mode |= mode_set(IXUSR);
62
63 mode |= mode_set(IRGRP);
64 mode |= mode_set(IWGRP);
65 mode |= mode_set(IXGRP);
66
67 mode |= mode_set(IROTH);
68 mode |= mode_set(IWOTH);
69 mode |= mode_set(IXOTH);
70
71 #undef mode_set
72
73 /* We use the host-side values for these */
74 inode->i_flags |= S_NOATIME | S_NOCMTIME;
75 inode->i_mapping->a_ops = &vboxsf_reg_aops;
76
77 if (SHFL_IS_DIRECTORY(attr->mode)) {
78 inode->i_mode = sbi->o.dmode_set ? sbi->o.dmode : mode;
79 inode->i_mode &= ~sbi->o.dmask;
80 inode->i_mode |= S_IFDIR;
81 inode->i_op = &vboxsf_dir_iops;
82 inode->i_fop = &vboxsf_dir_fops;
83 /*
84 * XXX: this probably should be set to the number of entries
85 * in the directory plus two (. ..)
86 */
87 set_nlink(inode, 1);
88 } else if (SHFL_IS_SYMLINK(attr->mode)) {
89 inode->i_mode = sbi->o.fmode_set ? sbi->o.fmode : mode;
90 inode->i_mode &= ~sbi->o.fmask;
91 inode->i_mode |= S_IFLNK;
92 inode->i_op = &vboxsf_lnk_iops;
93 set_nlink(inode, 1);
94 } else {
95 inode->i_mode = sbi->o.fmode_set ? sbi->o.fmode : mode;
96 inode->i_mode &= ~sbi->o.fmask;
97 inode->i_mode |= S_IFREG;
98 inode->i_op = &vboxsf_reg_iops;
99 inode->i_fop = &vboxsf_reg_fops;
100 set_nlink(inode, 1);
101 }
102
103 inode->i_uid = sbi->o.uid;
104 inode->i_gid = sbi->o.gid;
105
106 inode->i_size = info->size;
107 inode->i_blkbits = 12;
108 /* i_blocks always in units of 512 bytes! */
109 allocated = info->allocated + 511;
110 do_div(allocated, 512);
111 inode->i_blocks = allocated;
112
113 inode->i_atime = ns_to_timespec64(
114 info->access_time.ns_relative_to_unix_epoch);
115 inode->i_ctime = ns_to_timespec64(
116 info->change_time.ns_relative_to_unix_epoch);
117 inode->i_mtime = ns_to_timespec64(
118 info->modification_time.ns_relative_to_unix_epoch);
119 }
120
vboxsf_create_at_dentry(struct dentry * dentry,struct shfl_createparms * params)121 int vboxsf_create_at_dentry(struct dentry *dentry,
122 struct shfl_createparms *params)
123 {
124 struct vboxsf_sbi *sbi = VBOXSF_SBI(dentry->d_sb);
125 struct shfl_string *path;
126 int err;
127
128 path = vboxsf_path_from_dentry(sbi, dentry);
129 if (IS_ERR(path))
130 return PTR_ERR(path);
131
132 err = vboxsf_create(sbi->root, path, params);
133 __putname(path);
134
135 return err;
136 }
137
vboxsf_stat(struct vboxsf_sbi * sbi,struct shfl_string * path,struct shfl_fsobjinfo * info)138 int vboxsf_stat(struct vboxsf_sbi *sbi, struct shfl_string *path,
139 struct shfl_fsobjinfo *info)
140 {
141 struct shfl_createparms params = {};
142 int err;
143
144 params.handle = SHFL_HANDLE_NIL;
145 params.create_flags = SHFL_CF_LOOKUP | SHFL_CF_ACT_FAIL_IF_NEW;
146
147 err = vboxsf_create(sbi->root, path, ¶ms);
148 if (err)
149 return err;
150
151 if (params.result != SHFL_FILE_EXISTS)
152 return -ENOENT;
153
154 if (info)
155 *info = params.info;
156
157 return 0;
158 }
159
vboxsf_stat_dentry(struct dentry * dentry,struct shfl_fsobjinfo * info)160 int vboxsf_stat_dentry(struct dentry *dentry, struct shfl_fsobjinfo *info)
161 {
162 struct vboxsf_sbi *sbi = VBOXSF_SBI(dentry->d_sb);
163 struct shfl_string *path;
164 int err;
165
166 path = vboxsf_path_from_dentry(sbi, dentry);
167 if (IS_ERR(path))
168 return PTR_ERR(path);
169
170 err = vboxsf_stat(sbi, path, info);
171 __putname(path);
172 return err;
173 }
174
vboxsf_inode_revalidate(struct dentry * dentry)175 int vboxsf_inode_revalidate(struct dentry *dentry)
176 {
177 struct vboxsf_sbi *sbi;
178 struct vboxsf_inode *sf_i;
179 struct shfl_fsobjinfo info;
180 struct timespec64 prev_mtime;
181 struct inode *inode;
182 int err;
183
184 if (!dentry || !d_really_is_positive(dentry))
185 return -EINVAL;
186
187 inode = d_inode(dentry);
188 prev_mtime = inode->i_mtime;
189 sf_i = VBOXSF_I(inode);
190 sbi = VBOXSF_SBI(dentry->d_sb);
191 if (!sf_i->force_restat) {
192 if (time_before(jiffies, dentry->d_time + sbi->o.ttl))
193 return 0;
194 }
195
196 err = vboxsf_stat_dentry(dentry, &info);
197 if (err)
198 return err;
199
200 dentry->d_time = jiffies;
201 sf_i->force_restat = 0;
202 vboxsf_init_inode(sbi, inode, &info);
203
204 /*
205 * If the file was changed on the host side we need to invalidate the
206 * page-cache for it. Note this also gets triggered by our own writes,
207 * this is unavoidable.
208 */
209 if (timespec64_compare(&inode->i_mtime, &prev_mtime) > 0)
210 invalidate_inode_pages2(inode->i_mapping);
211
212 return 0;
213 }
214
vboxsf_getattr(const struct path * path,struct kstat * kstat,u32 request_mask,unsigned int flags)215 int vboxsf_getattr(const struct path *path, struct kstat *kstat,
216 u32 request_mask, unsigned int flags)
217 {
218 int err;
219 struct dentry *dentry = path->dentry;
220 struct inode *inode = d_inode(dentry);
221 struct vboxsf_inode *sf_i = VBOXSF_I(inode);
222
223 switch (flags & AT_STATX_SYNC_TYPE) {
224 case AT_STATX_DONT_SYNC:
225 err = 0;
226 break;
227 case AT_STATX_FORCE_SYNC:
228 sf_i->force_restat = 1;
229 fallthrough;
230 default:
231 err = vboxsf_inode_revalidate(dentry);
232 }
233 if (err)
234 return err;
235
236 generic_fillattr(d_inode(dentry), kstat);
237 return 0;
238 }
239
vboxsf_setattr(struct dentry * dentry,struct iattr * iattr)240 int vboxsf_setattr(struct dentry *dentry, struct iattr *iattr)
241 {
242 struct vboxsf_inode *sf_i = VBOXSF_I(d_inode(dentry));
243 struct vboxsf_sbi *sbi = VBOXSF_SBI(dentry->d_sb);
244 struct shfl_createparms params = {};
245 struct shfl_fsobjinfo info = {};
246 u32 buf_len;
247 int err;
248
249 params.handle = SHFL_HANDLE_NIL;
250 params.create_flags = SHFL_CF_ACT_OPEN_IF_EXISTS |
251 SHFL_CF_ACT_FAIL_IF_NEW |
252 SHFL_CF_ACCESS_ATTR_WRITE;
253
254 /* this is at least required for Posix hosts */
255 if (iattr->ia_valid & ATTR_SIZE)
256 params.create_flags |= SHFL_CF_ACCESS_WRITE;
257
258 err = vboxsf_create_at_dentry(dentry, ¶ms);
259 if (err || params.result != SHFL_FILE_EXISTS)
260 return err ? err : -ENOENT;
261
262 #define mode_set(r) ((iattr->ia_mode & (S_##r)) ? SHFL_UNIX_##r : 0)
263
264 /*
265 * Setting the file size and setting the other attributes has to
266 * be handled separately.
267 */
268 if (iattr->ia_valid & (ATTR_MODE | ATTR_ATIME | ATTR_MTIME)) {
269 if (iattr->ia_valid & ATTR_MODE) {
270 info.attr.mode = mode_set(IRUSR);
271 info.attr.mode |= mode_set(IWUSR);
272 info.attr.mode |= mode_set(IXUSR);
273 info.attr.mode |= mode_set(IRGRP);
274 info.attr.mode |= mode_set(IWGRP);
275 info.attr.mode |= mode_set(IXGRP);
276 info.attr.mode |= mode_set(IROTH);
277 info.attr.mode |= mode_set(IWOTH);
278 info.attr.mode |= mode_set(IXOTH);
279
280 if (iattr->ia_mode & S_IFDIR)
281 info.attr.mode |= SHFL_TYPE_DIRECTORY;
282 else
283 info.attr.mode |= SHFL_TYPE_FILE;
284 }
285
286 if (iattr->ia_valid & ATTR_ATIME)
287 info.access_time.ns_relative_to_unix_epoch =
288 timespec64_to_ns(&iattr->ia_atime);
289
290 if (iattr->ia_valid & ATTR_MTIME)
291 info.modification_time.ns_relative_to_unix_epoch =
292 timespec64_to_ns(&iattr->ia_mtime);
293
294 /*
295 * Ignore ctime (inode change time) as it can't be set
296 * from userland anyway.
297 */
298
299 buf_len = sizeof(info);
300 err = vboxsf_fsinfo(sbi->root, params.handle,
301 SHFL_INFO_SET | SHFL_INFO_FILE, &buf_len,
302 &info);
303 if (err) {
304 vboxsf_close(sbi->root, params.handle);
305 return err;
306 }
307
308 /* the host may have given us different attr then requested */
309 sf_i->force_restat = 1;
310 }
311
312 #undef mode_set
313
314 if (iattr->ia_valid & ATTR_SIZE) {
315 memset(&info, 0, sizeof(info));
316 info.size = iattr->ia_size;
317 buf_len = sizeof(info);
318 err = vboxsf_fsinfo(sbi->root, params.handle,
319 SHFL_INFO_SET | SHFL_INFO_SIZE, &buf_len,
320 &info);
321 if (err) {
322 vboxsf_close(sbi->root, params.handle);
323 return err;
324 }
325
326 /* the host may have given us different attr then requested */
327 sf_i->force_restat = 1;
328 }
329
330 vboxsf_close(sbi->root, params.handle);
331
332 /* Update the inode with what the host has actually given us. */
333 if (sf_i->force_restat)
334 vboxsf_inode_revalidate(dentry);
335
336 return 0;
337 }
338
339 /*
340 * [dentry] contains string encoded in coding system that corresponds
341 * to [sbi]->nls, we must convert it to UTF8 here.
342 * Returns a shfl_string allocated through __getname (must be freed using
343 * __putname), or an ERR_PTR on error.
344 */
vboxsf_path_from_dentry(struct vboxsf_sbi * sbi,struct dentry * dentry)345 struct shfl_string *vboxsf_path_from_dentry(struct vboxsf_sbi *sbi,
346 struct dentry *dentry)
347 {
348 struct shfl_string *shfl_path;
349 int path_len, out_len, nb;
350 char *buf, *path;
351 wchar_t uni;
352 u8 *out;
353
354 buf = __getname();
355 if (!buf)
356 return ERR_PTR(-ENOMEM);
357
358 path = dentry_path_raw(dentry, buf, PATH_MAX);
359 if (IS_ERR(path)) {
360 __putname(buf);
361 return ERR_CAST(path);
362 }
363 path_len = strlen(path);
364
365 if (sbi->nls) {
366 shfl_path = __getname();
367 if (!shfl_path) {
368 __putname(buf);
369 return ERR_PTR(-ENOMEM);
370 }
371
372 out = shfl_path->string.utf8;
373 out_len = PATH_MAX - SHFLSTRING_HEADER_SIZE - 1;
374
375 while (path_len) {
376 nb = sbi->nls->char2uni(path, path_len, &uni);
377 if (nb < 0) {
378 __putname(shfl_path);
379 __putname(buf);
380 return ERR_PTR(-EINVAL);
381 }
382 path += nb;
383 path_len -= nb;
384
385 nb = utf32_to_utf8(uni, out, out_len);
386 if (nb < 0) {
387 __putname(shfl_path);
388 __putname(buf);
389 return ERR_PTR(-ENAMETOOLONG);
390 }
391 out += nb;
392 out_len -= nb;
393 }
394 *out = 0;
395 shfl_path->length = out - shfl_path->string.utf8;
396 shfl_path->size = shfl_path->length + 1;
397 __putname(buf);
398 } else {
399 if ((SHFLSTRING_HEADER_SIZE + path_len + 1) > PATH_MAX) {
400 __putname(buf);
401 return ERR_PTR(-ENAMETOOLONG);
402 }
403 /*
404 * dentry_path stores the name at the end of buf, but the
405 * shfl_string string we return must be properly aligned.
406 */
407 shfl_path = (struct shfl_string *)buf;
408 memmove(shfl_path->string.utf8, path, path_len);
409 shfl_path->string.utf8[path_len] = 0;
410 shfl_path->length = path_len;
411 shfl_path->size = path_len + 1;
412 }
413
414 return shfl_path;
415 }
416
vboxsf_nlscpy(struct vboxsf_sbi * sbi,char * name,size_t name_bound_len,const unsigned char * utf8_name,size_t utf8_len)417 int vboxsf_nlscpy(struct vboxsf_sbi *sbi, char *name, size_t name_bound_len,
418 const unsigned char *utf8_name, size_t utf8_len)
419 {
420 const char *in;
421 char *out;
422 size_t out_len;
423 size_t out_bound_len;
424 size_t in_bound_len;
425
426 in = utf8_name;
427 in_bound_len = utf8_len;
428
429 out = name;
430 out_len = 0;
431 /* Reserve space for terminating 0 */
432 out_bound_len = name_bound_len - 1;
433
434 while (in_bound_len) {
435 int nb;
436 unicode_t uni;
437
438 nb = utf8_to_utf32(in, in_bound_len, &uni);
439 if (nb < 0)
440 return -EINVAL;
441
442 in += nb;
443 in_bound_len -= nb;
444
445 nb = sbi->nls->uni2char(uni, out, out_bound_len);
446 if (nb < 0)
447 return nb;
448
449 out += nb;
450 out_bound_len -= nb;
451 out_len += nb;
452 }
453
454 *out = 0;
455
456 return 0;
457 }
458
vboxsf_dir_buf_alloc(struct list_head * list)459 static struct vboxsf_dir_buf *vboxsf_dir_buf_alloc(struct list_head *list)
460 {
461 struct vboxsf_dir_buf *b;
462
463 b = kmalloc(sizeof(*b), GFP_KERNEL);
464 if (!b)
465 return NULL;
466
467 b->buf = kmalloc(DIR_BUFFER_SIZE, GFP_KERNEL);
468 if (!b->buf) {
469 kfree(b);
470 return NULL;
471 }
472
473 b->entries = 0;
474 b->used = 0;
475 b->free = DIR_BUFFER_SIZE;
476 list_add(&b->head, list);
477
478 return b;
479 }
480
vboxsf_dir_buf_free(struct vboxsf_dir_buf * b)481 static void vboxsf_dir_buf_free(struct vboxsf_dir_buf *b)
482 {
483 list_del(&b->head);
484 kfree(b->buf);
485 kfree(b);
486 }
487
vboxsf_dir_info_alloc(void)488 struct vboxsf_dir_info *vboxsf_dir_info_alloc(void)
489 {
490 struct vboxsf_dir_info *p;
491
492 p = kmalloc(sizeof(*p), GFP_KERNEL);
493 if (!p)
494 return NULL;
495
496 INIT_LIST_HEAD(&p->info_list);
497 return p;
498 }
499
vboxsf_dir_info_free(struct vboxsf_dir_info * p)500 void vboxsf_dir_info_free(struct vboxsf_dir_info *p)
501 {
502 struct list_head *list, *pos, *tmp;
503
504 list = &p->info_list;
505 list_for_each_safe(pos, tmp, list) {
506 struct vboxsf_dir_buf *b;
507
508 b = list_entry(pos, struct vboxsf_dir_buf, head);
509 vboxsf_dir_buf_free(b);
510 }
511 kfree(p);
512 }
513
vboxsf_dir_read_all(struct vboxsf_sbi * sbi,struct vboxsf_dir_info * sf_d,u64 handle)514 int vboxsf_dir_read_all(struct vboxsf_sbi *sbi, struct vboxsf_dir_info *sf_d,
515 u64 handle)
516 {
517 struct vboxsf_dir_buf *b;
518 u32 entries, size;
519 int err = 0;
520 void *buf;
521
522 /* vboxsf_dirinfo returns 1 on end of dir */
523 while (err == 0) {
524 b = vboxsf_dir_buf_alloc(&sf_d->info_list);
525 if (!b) {
526 err = -ENOMEM;
527 break;
528 }
529
530 buf = b->buf;
531 size = b->free;
532
533 err = vboxsf_dirinfo(sbi->root, handle, NULL, 0, 0,
534 &size, buf, &entries);
535 if (err < 0)
536 break;
537
538 b->entries += entries;
539 b->free -= size;
540 b->used += size;
541 }
542
543 if (b && b->used == 0)
544 vboxsf_dir_buf_free(b);
545
546 /* -EILSEQ means the host could not translate a filename, ignore */
547 if (err > 0 || err == -EILSEQ)
548 err = 0;
549
550 return err;
551 }
552
