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/pagemap.h>
13 #include <linux/vfs.h>
14 #include "vfsmod.h"
15
vboxsf_new_inode(struct super_block * sb)16 struct inode *vboxsf_new_inode(struct super_block *sb)
17 {
18 struct vboxsf_sbi *sbi = VBOXSF_SBI(sb);
19 struct inode *inode;
20 unsigned long flags;
21 int cursor, ret;
22 u32 gen;
23
24 inode = new_inode(sb);
25 if (!inode)
26 return ERR_PTR(-ENOMEM);
27
28 idr_preload(GFP_KERNEL);
29 spin_lock_irqsave(&sbi->ino_idr_lock, flags);
30 cursor = idr_get_cursor(&sbi->ino_idr);
31 ret = idr_alloc_cyclic(&sbi->ino_idr, inode, 1, 0, GFP_ATOMIC);
32 if (ret >= 0 && ret < cursor)
33 sbi->next_generation++;
34 gen = sbi->next_generation;
35 spin_unlock_irqrestore(&sbi->ino_idr_lock, flags);
36 idr_preload_end();
37
38 if (ret < 0) {
39 iput(inode);
40 return ERR_PTR(ret);
41 }
42
43 inode->i_ino = ret;
44 inode->i_generation = gen;
45 return inode;
46 }
47
48 /* 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,bool reinit)49 int vboxsf_init_inode(struct vboxsf_sbi *sbi, struct inode *inode,
50 const struct shfl_fsobjinfo *info, bool reinit)
51 {
52 const struct shfl_fsobjattr *attr;
53 s64 allocated;
54 umode_t mode;
55
56 attr = &info->attr;
57
58 #define mode_set(r) ((attr->mode & (SHFL_UNIX_##r)) ? (S_##r) : 0)
59
60 mode = mode_set(IRUSR);
61 mode |= mode_set(IWUSR);
62 mode |= mode_set(IXUSR);
63
64 mode |= mode_set(IRGRP);
65 mode |= mode_set(IWGRP);
66 mode |= mode_set(IXGRP);
67
68 mode |= mode_set(IROTH);
69 mode |= mode_set(IWOTH);
70 mode |= mode_set(IXOTH);
71
72 #undef mode_set
73
74 /* We use the host-side values for these */
75 inode->i_flags |= S_NOATIME | S_NOCMTIME;
76 inode->i_mapping->a_ops = &vboxsf_reg_aops;
77
78 if (SHFL_IS_DIRECTORY(attr->mode)) {
79 if (sbi->o.dmode_set)
80 mode = sbi->o.dmode;
81 mode &= ~sbi->o.dmask;
82 mode |= S_IFDIR;
83 if (!reinit) {
84 inode->i_op = &vboxsf_dir_iops;
85 inode->i_fop = &vboxsf_dir_fops;
86 /*
87 * XXX: this probably should be set to the number of entries
88 * in the directory plus two (. ..)
89 */
90 set_nlink(inode, 1);
91 } else if (!S_ISDIR(inode->i_mode))
92 return -ESTALE;
93 inode->i_mode = mode;
94 } else if (SHFL_IS_SYMLINK(attr->mode)) {
95 if (sbi->o.fmode_set)
96 mode = sbi->o.fmode;
97 mode &= ~sbi->o.fmask;
98 mode |= S_IFLNK;
99 if (!reinit) {
100 inode->i_op = &vboxsf_lnk_iops;
101 set_nlink(inode, 1);
102 } else if (!S_ISLNK(inode->i_mode))
103 return -ESTALE;
104 inode->i_mode = mode;
105 } else {
106 if (sbi->o.fmode_set)
107 mode = sbi->o.fmode;
108 mode &= ~sbi->o.fmask;
109 mode |= S_IFREG;
110 if (!reinit) {
111 inode->i_op = &vboxsf_reg_iops;
112 inode->i_fop = &vboxsf_reg_fops;
113 set_nlink(inode, 1);
114 } else if (!S_ISREG(inode->i_mode))
115 return -ESTALE;
116 inode->i_mode = mode;
117 }
118
119 inode->i_uid = sbi->o.uid;
120 inode->i_gid = sbi->o.gid;
121
122 inode->i_size = info->size;
123 inode->i_blkbits = 12;
124 /* i_blocks always in units of 512 bytes! */
125 allocated = info->allocated + 511;
126 do_div(allocated, 512);
127 inode->i_blocks = allocated;
128
129 inode_set_atime_to_ts(inode,
130 ns_to_timespec64(info->access_time.ns_relative_to_unix_epoch));
131 inode_set_ctime_to_ts(inode,
132 ns_to_timespec64(info->change_time.ns_relative_to_unix_epoch));
133 inode_set_mtime_to_ts(inode,
134 ns_to_timespec64(info->modification_time.ns_relative_to_unix_epoch));
135 return 0;
136 }
137
vboxsf_create_at_dentry(struct dentry * dentry,struct shfl_createparms * params)138 int vboxsf_create_at_dentry(struct dentry *dentry,
139 struct shfl_createparms *params)
140 {
141 struct vboxsf_sbi *sbi = VBOXSF_SBI(dentry->d_sb);
142 struct shfl_string *path;
143 int err;
144
145 path = vboxsf_path_from_dentry(sbi, dentry);
146 if (IS_ERR(path))
147 return PTR_ERR(path);
148
149 err = vboxsf_create(sbi->root, path, params);
150 __putname(path);
151
152 return err;
153 }
154
vboxsf_stat(struct vboxsf_sbi * sbi,struct shfl_string * path,struct shfl_fsobjinfo * info)155 int vboxsf_stat(struct vboxsf_sbi *sbi, struct shfl_string *path,
156 struct shfl_fsobjinfo *info)
157 {
158 struct shfl_createparms params = {};
159 int err;
160
161 params.handle = SHFL_HANDLE_NIL;
162 params.create_flags = SHFL_CF_LOOKUP | SHFL_CF_ACT_FAIL_IF_NEW;
163
164 err = vboxsf_create(sbi->root, path, ¶ms);
165 if (err)
166 return err;
167
168 if (params.result != SHFL_FILE_EXISTS)
169 return -ENOENT;
170
171 if (info)
172 *info = params.info;
173
174 return 0;
175 }
176
vboxsf_stat_dentry(struct dentry * dentry,struct shfl_fsobjinfo * info)177 int vboxsf_stat_dentry(struct dentry *dentry, struct shfl_fsobjinfo *info)
178 {
179 struct vboxsf_sbi *sbi = VBOXSF_SBI(dentry->d_sb);
180 struct shfl_string *path;
181 int err;
182
183 path = vboxsf_path_from_dentry(sbi, dentry);
184 if (IS_ERR(path))
185 return PTR_ERR(path);
186
187 err = vboxsf_stat(sbi, path, info);
188 __putname(path);
189 return err;
190 }
191
vboxsf_inode_revalidate(struct dentry * dentry)192 int vboxsf_inode_revalidate(struct dentry *dentry)
193 {
194 struct vboxsf_sbi *sbi;
195 struct vboxsf_inode *sf_i;
196 struct shfl_fsobjinfo info;
197 struct timespec64 mtime, prev_mtime;
198 struct inode *inode;
199 int err;
200
201 if (!dentry || !d_really_is_positive(dentry))
202 return -EINVAL;
203
204 inode = d_inode(dentry);
205 prev_mtime = inode_get_mtime(inode);
206 sf_i = VBOXSF_I(inode);
207 sbi = VBOXSF_SBI(dentry->d_sb);
208 if (!sf_i->force_restat) {
209 if (time_before(jiffies, dentry->d_time + sbi->o.ttl))
210 return 0;
211 }
212
213 err = vboxsf_stat_dentry(dentry, &info);
214 if (err)
215 return err;
216
217 dentry->d_time = jiffies;
218 sf_i->force_restat = 0;
219 err = vboxsf_init_inode(sbi, inode, &info, true);
220 if (err)
221 return err;
222
223 /*
224 * If the file was changed on the host side we need to invalidate the
225 * page-cache for it. Note this also gets triggered by our own writes,
226 * this is unavoidable.
227 */
228 mtime = inode_get_mtime(inode);
229 if (timespec64_compare(&mtime, &prev_mtime) > 0)
230 invalidate_inode_pages2(inode->i_mapping);
231
232 return 0;
233 }
234
vboxsf_getattr(struct mnt_idmap * idmap,const struct path * path,struct kstat * kstat,u32 request_mask,unsigned int flags)235 int vboxsf_getattr(struct mnt_idmap *idmap, const struct path *path,
236 struct kstat *kstat, u32 request_mask, unsigned int flags)
237 {
238 int err;
239 struct dentry *dentry = path->dentry;
240 struct inode *inode = d_inode(dentry);
241 struct vboxsf_inode *sf_i = VBOXSF_I(inode);
242
243 switch (flags & AT_STATX_SYNC_TYPE) {
244 case AT_STATX_DONT_SYNC:
245 err = 0;
246 break;
247 case AT_STATX_FORCE_SYNC:
248 sf_i->force_restat = 1;
249 fallthrough;
250 default:
251 err = vboxsf_inode_revalidate(dentry);
252 }
253 if (err)
254 return err;
255
256 generic_fillattr(&nop_mnt_idmap, request_mask, d_inode(dentry), kstat);
257 return 0;
258 }
259
vboxsf_setattr(struct mnt_idmap * idmap,struct dentry * dentry,struct iattr * iattr)260 int vboxsf_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
261 struct iattr *iattr)
262 {
263 struct vboxsf_inode *sf_i = VBOXSF_I(d_inode(dentry));
264 struct vboxsf_sbi *sbi = VBOXSF_SBI(dentry->d_sb);
265 struct shfl_createparms params = {};
266 struct shfl_fsobjinfo info = {};
267 u32 buf_len;
268 int err;
269
270 params.handle = SHFL_HANDLE_NIL;
271 params.create_flags = SHFL_CF_ACT_OPEN_IF_EXISTS |
272 SHFL_CF_ACT_FAIL_IF_NEW |
273 SHFL_CF_ACCESS_ATTR_WRITE;
274
275 /* this is at least required for Posix hosts */
276 if (iattr->ia_valid & ATTR_SIZE)
277 params.create_flags |= SHFL_CF_ACCESS_WRITE;
278
279 err = vboxsf_create_at_dentry(dentry, ¶ms);
280 if (err || params.result != SHFL_FILE_EXISTS)
281 return err ? err : -ENOENT;
282
283 #define mode_set(r) ((iattr->ia_mode & (S_##r)) ? SHFL_UNIX_##r : 0)
284
285 /*
286 * Setting the file size and setting the other attributes has to
287 * be handled separately.
288 */
289 if (iattr->ia_valid & (ATTR_MODE | ATTR_ATIME | ATTR_MTIME)) {
290 if (iattr->ia_valid & ATTR_MODE) {
291 info.attr.mode = mode_set(IRUSR);
292 info.attr.mode |= mode_set(IWUSR);
293 info.attr.mode |= mode_set(IXUSR);
294 info.attr.mode |= mode_set(IRGRP);
295 info.attr.mode |= mode_set(IWGRP);
296 info.attr.mode |= mode_set(IXGRP);
297 info.attr.mode |= mode_set(IROTH);
298 info.attr.mode |= mode_set(IWOTH);
299 info.attr.mode |= mode_set(IXOTH);
300
301 if (iattr->ia_mode & S_IFDIR)
302 info.attr.mode |= SHFL_TYPE_DIRECTORY;
303 else
304 info.attr.mode |= SHFL_TYPE_FILE;
305 }
306
307 if (iattr->ia_valid & ATTR_ATIME)
308 info.access_time.ns_relative_to_unix_epoch =
309 timespec64_to_ns(&iattr->ia_atime);
310
311 if (iattr->ia_valid & ATTR_MTIME)
312 info.modification_time.ns_relative_to_unix_epoch =
313 timespec64_to_ns(&iattr->ia_mtime);
314
315 /*
316 * Ignore ctime (inode change time) as it can't be set
317 * from userland anyway.
318 */
319
320 buf_len = sizeof(info);
321 err = vboxsf_fsinfo(sbi->root, params.handle,
322 SHFL_INFO_SET | SHFL_INFO_FILE, &buf_len,
323 &info);
324 if (err) {
325 vboxsf_close(sbi->root, params.handle);
326 return err;
327 }
328
329 /* the host may have given us different attr then requested */
330 sf_i->force_restat = 1;
331 }
332
333 #undef mode_set
334
335 if (iattr->ia_valid & ATTR_SIZE) {
336 memset(&info, 0, sizeof(info));
337 info.size = iattr->ia_size;
338 buf_len = sizeof(info);
339 err = vboxsf_fsinfo(sbi->root, params.handle,
340 SHFL_INFO_SET | SHFL_INFO_SIZE, &buf_len,
341 &info);
342 if (err) {
343 vboxsf_close(sbi->root, params.handle);
344 return err;
345 }
346
347 /* the host may have given us different attr then requested */
348 sf_i->force_restat = 1;
349 }
350
351 vboxsf_close(sbi->root, params.handle);
352
353 /* Update the inode with what the host has actually given us. */
354 if (sf_i->force_restat)
355 vboxsf_inode_revalidate(dentry);
356
357 return 0;
358 }
359
360 /*
361 * [dentry] contains string encoded in coding system that corresponds
362 * to [sbi]->nls, we must convert it to UTF8 here.
363 * Returns a shfl_string allocated through __getname (must be freed using
364 * __putname), or an ERR_PTR on error.
365 */
vboxsf_path_from_dentry(struct vboxsf_sbi * sbi,struct dentry * dentry)366 struct shfl_string *vboxsf_path_from_dentry(struct vboxsf_sbi *sbi,
367 struct dentry *dentry)
368 {
369 struct shfl_string *shfl_path;
370 int path_len, out_len, nb;
371 char *buf, *path;
372 wchar_t uni;
373 u8 *out;
374
375 buf = __getname();
376 if (!buf)
377 return ERR_PTR(-ENOMEM);
378
379 path = dentry_path_raw(dentry, buf, PATH_MAX);
380 if (IS_ERR(path)) {
381 __putname(buf);
382 return ERR_CAST(path);
383 }
384 path_len = strlen(path);
385
386 if (sbi->nls) {
387 shfl_path = __getname();
388 if (!shfl_path) {
389 __putname(buf);
390 return ERR_PTR(-ENOMEM);
391 }
392
393 out = shfl_path->string.utf8;
394 out_len = PATH_MAX - SHFLSTRING_HEADER_SIZE - 1;
395
396 while (path_len) {
397 nb = sbi->nls->char2uni(path, path_len, &uni);
398 if (nb < 0) {
399 __putname(shfl_path);
400 __putname(buf);
401 return ERR_PTR(-EINVAL);
402 }
403 path += nb;
404 path_len -= nb;
405
406 nb = utf32_to_utf8(uni, out, out_len);
407 if (nb < 0) {
408 __putname(shfl_path);
409 __putname(buf);
410 return ERR_PTR(-ENAMETOOLONG);
411 }
412 out += nb;
413 out_len -= nb;
414 }
415 *out = 0;
416 shfl_path->length = out - shfl_path->string.utf8;
417 shfl_path->size = shfl_path->length + 1;
418 __putname(buf);
419 } else {
420 if ((SHFLSTRING_HEADER_SIZE + path_len + 1) > PATH_MAX) {
421 __putname(buf);
422 return ERR_PTR(-ENAMETOOLONG);
423 }
424 /*
425 * dentry_path stores the name at the end of buf, but the
426 * shfl_string string we return must be properly aligned.
427 */
428 shfl_path = (struct shfl_string *)buf;
429 memmove(shfl_path->string.utf8, path, path_len);
430 shfl_path->string.utf8[path_len] = 0;
431 shfl_path->length = path_len;
432 shfl_path->size = path_len + 1;
433 }
434
435 return shfl_path;
436 }
437
vboxsf_nlscpy(struct vboxsf_sbi * sbi,char * name,size_t name_bound_len,const unsigned char * utf8_name,size_t utf8_len)438 int vboxsf_nlscpy(struct vboxsf_sbi *sbi, char *name, size_t name_bound_len,
439 const unsigned char *utf8_name, size_t utf8_len)
440 {
441 const char *in;
442 char *out;
443 size_t out_bound_len;
444 size_t in_bound_len;
445
446 in = utf8_name;
447 in_bound_len = utf8_len;
448
449 out = name;
450 /* Reserve space for terminating 0 */
451 out_bound_len = name_bound_len - 1;
452
453 while (in_bound_len) {
454 int nb;
455 unicode_t uni;
456
457 nb = utf8_to_utf32(in, in_bound_len, &uni);
458 if (nb < 0)
459 return -EINVAL;
460
461 in += nb;
462 in_bound_len -= nb;
463
464 nb = sbi->nls->uni2char(uni, out, out_bound_len);
465 if (nb < 0)
466 return nb;
467
468 out += nb;
469 out_bound_len -= nb;
470 }
471
472 *out = 0;
473
474 return 0;
475 }
476
vboxsf_dir_buf_alloc(struct list_head * list)477 static struct vboxsf_dir_buf *vboxsf_dir_buf_alloc(struct list_head *list)
478 {
479 struct vboxsf_dir_buf *b;
480
481 b = kmalloc(sizeof(*b), GFP_KERNEL);
482 if (!b)
483 return NULL;
484
485 b->buf = kmalloc(DIR_BUFFER_SIZE, GFP_KERNEL);
486 if (!b->buf) {
487 kfree(b);
488 return NULL;
489 }
490
491 b->entries = 0;
492 b->used = 0;
493 b->free = DIR_BUFFER_SIZE;
494 list_add(&b->head, list);
495
496 return b;
497 }
498
vboxsf_dir_buf_free(struct vboxsf_dir_buf * b)499 static void vboxsf_dir_buf_free(struct vboxsf_dir_buf *b)
500 {
501 list_del(&b->head);
502 kfree(b->buf);
503 kfree(b);
504 }
505
vboxsf_dir_info_alloc(void)506 struct vboxsf_dir_info *vboxsf_dir_info_alloc(void)
507 {
508 struct vboxsf_dir_info *p;
509
510 p = kmalloc(sizeof(*p), GFP_KERNEL);
511 if (!p)
512 return NULL;
513
514 INIT_LIST_HEAD(&p->info_list);
515 return p;
516 }
517
vboxsf_dir_info_free(struct vboxsf_dir_info * p)518 void vboxsf_dir_info_free(struct vboxsf_dir_info *p)
519 {
520 struct list_head *list, *pos, *tmp;
521
522 list = &p->info_list;
523 list_for_each_safe(pos, tmp, list) {
524 struct vboxsf_dir_buf *b;
525
526 b = list_entry(pos, struct vboxsf_dir_buf, head);
527 vboxsf_dir_buf_free(b);
528 }
529 kfree(p);
530 }
531
vboxsf_dir_read_all(struct vboxsf_sbi * sbi,struct vboxsf_dir_info * sf_d,u64 handle)532 int vboxsf_dir_read_all(struct vboxsf_sbi *sbi, struct vboxsf_dir_info *sf_d,
533 u64 handle)
534 {
535 struct vboxsf_dir_buf *b;
536 u32 entries, size;
537 int err = 0;
538 void *buf;
539
540 /* vboxsf_dirinfo returns 1 on end of dir */
541 while (err == 0) {
542 b = vboxsf_dir_buf_alloc(&sf_d->info_list);
543 if (!b) {
544 err = -ENOMEM;
545 break;
546 }
547
548 buf = b->buf;
549 size = b->free;
550
551 err = vboxsf_dirinfo(sbi->root, handle, NULL, 0, 0,
552 &size, buf, &entries);
553 if (err < 0)
554 break;
555
556 b->entries += entries;
557 b->free -= size;
558 b->used += size;
559 }
560
561 if (b && b->used == 0)
562 vboxsf_dir_buf_free(b);
563
564 /* -EILSEQ means the host could not translate a filename, ignore */
565 if (err > 0 || err == -EILSEQ)
566 err = 0;
567
568 return err;
569 }
570