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9ac29fd3 MS |
1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* | |
3 | * Copyright (C) 2017 Red Hat, Inc. | |
4 | */ | |
5 | ||
6 | #include "fuse_i.h" | |
7 | ||
8 | #include <linux/uio.h> | |
9 | #include <linux/compat.h> | |
10 | #include <linux/fileattr.h> | |
11 | ||
02c0cab8 MS |
12 | static ssize_t fuse_send_ioctl(struct fuse_mount *fm, struct fuse_args *args) |
13 | { | |
14 | ssize_t ret = fuse_simple_request(fm, args); | |
15 | ||
16 | /* Translate ENOSYS, which shouldn't be returned from fs */ | |
17 | if (ret == -ENOSYS) | |
18 | ret = -ENOTTY; | |
19 | ||
20 | return ret; | |
21 | } | |
22 | ||
9ac29fd3 MS |
23 | /* |
24 | * CUSE servers compiled on 32bit broke on 64bit kernels because the | |
25 | * ABI was defined to be 'struct iovec' which is different on 32bit | |
26 | * and 64bit. Fortunately we can determine which structure the server | |
27 | * used from the size of the reply. | |
28 | */ | |
29 | static int fuse_copy_ioctl_iovec_old(struct iovec *dst, void *src, | |
30 | size_t transferred, unsigned count, | |
31 | bool is_compat) | |
32 | { | |
33 | #ifdef CONFIG_COMPAT | |
34 | if (count * sizeof(struct compat_iovec) == transferred) { | |
35 | struct compat_iovec *ciov = src; | |
36 | unsigned i; | |
37 | ||
38 | /* | |
39 | * With this interface a 32bit server cannot support | |
40 | * non-compat (i.e. ones coming from 64bit apps) ioctl | |
41 | * requests | |
42 | */ | |
43 | if (!is_compat) | |
44 | return -EINVAL; | |
45 | ||
46 | for (i = 0; i < count; i++) { | |
47 | dst[i].iov_base = compat_ptr(ciov[i].iov_base); | |
48 | dst[i].iov_len = ciov[i].iov_len; | |
49 | } | |
50 | return 0; | |
51 | } | |
52 | #endif | |
53 | ||
54 | if (count * sizeof(struct iovec) != transferred) | |
55 | return -EIO; | |
56 | ||
57 | memcpy(dst, src, transferred); | |
58 | return 0; | |
59 | } | |
60 | ||
61 | /* Make sure iov_length() won't overflow */ | |
62 | static int fuse_verify_ioctl_iov(struct fuse_conn *fc, struct iovec *iov, | |
63 | size_t count) | |
64 | { | |
65 | size_t n; | |
66 | u32 max = fc->max_pages << PAGE_SHIFT; | |
67 | ||
68 | for (n = 0; n < count; n++, iov++) { | |
69 | if (iov->iov_len > (size_t) max) | |
70 | return -ENOMEM; | |
71 | max -= iov->iov_len; | |
72 | } | |
73 | return 0; | |
74 | } | |
75 | ||
76 | static int fuse_copy_ioctl_iovec(struct fuse_conn *fc, struct iovec *dst, | |
77 | void *src, size_t transferred, unsigned count, | |
78 | bool is_compat) | |
79 | { | |
80 | unsigned i; | |
81 | struct fuse_ioctl_iovec *fiov = src; | |
82 | ||
83 | if (fc->minor < 16) { | |
84 | return fuse_copy_ioctl_iovec_old(dst, src, transferred, | |
85 | count, is_compat); | |
86 | } | |
87 | ||
88 | if (count * sizeof(struct fuse_ioctl_iovec) != transferred) | |
89 | return -EIO; | |
90 | ||
91 | for (i = 0; i < count; i++) { | |
92 | /* Did the server supply an inappropriate value? */ | |
93 | if (fiov[i].base != (unsigned long) fiov[i].base || | |
94 | fiov[i].len != (unsigned long) fiov[i].len) | |
95 | return -EIO; | |
96 | ||
97 | dst[i].iov_base = (void __user *) (unsigned long) fiov[i].base; | |
98 | dst[i].iov_len = (size_t) fiov[i].len; | |
99 | ||
100 | #ifdef CONFIG_COMPAT | |
101 | if (is_compat && | |
102 | (ptr_to_compat(dst[i].iov_base) != fiov[i].base || | |
103 | (compat_size_t) dst[i].iov_len != fiov[i].len)) | |
104 | return -EIO; | |
105 | #endif | |
106 | } | |
107 | ||
108 | return 0; | |
109 | } | |
110 | ||
111 | ||
112 | /* | |
113 | * For ioctls, there is no generic way to determine how much memory | |
114 | * needs to be read and/or written. Furthermore, ioctls are allowed | |
115 | * to dereference the passed pointer, so the parameter requires deep | |
116 | * copying but FUSE has no idea whatsoever about what to copy in or | |
117 | * out. | |
118 | * | |
119 | * This is solved by allowing FUSE server to retry ioctl with | |
120 | * necessary in/out iovecs. Let's assume the ioctl implementation | |
121 | * needs to read in the following structure. | |
122 | * | |
123 | * struct a { | |
124 | * char *buf; | |
125 | * size_t buflen; | |
126 | * } | |
127 | * | |
128 | * On the first callout to FUSE server, inarg->in_size and | |
129 | * inarg->out_size will be NULL; then, the server completes the ioctl | |
130 | * with FUSE_IOCTL_RETRY set in out->flags, out->in_iovs set to 1 and | |
131 | * the actual iov array to | |
132 | * | |
133 | * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) } } | |
134 | * | |
135 | * which tells FUSE to copy in the requested area and retry the ioctl. | |
136 | * On the second round, the server has access to the structure and | |
137 | * from that it can tell what to look for next, so on the invocation, | |
138 | * it sets FUSE_IOCTL_RETRY, out->in_iovs to 2 and iov array to | |
139 | * | |
140 | * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) }, | |
141 | * { .iov_base = a.buf, .iov_len = a.buflen } } | |
142 | * | |
143 | * FUSE will copy both struct a and the pointed buffer from the | |
144 | * process doing the ioctl and retry ioctl with both struct a and the | |
145 | * buffer. | |
146 | * | |
147 | * This time, FUSE server has everything it needs and completes ioctl | |
148 | * without FUSE_IOCTL_RETRY which finishes the ioctl call. | |
149 | * | |
150 | * Copying data out works the same way. | |
151 | * | |
152 | * Note that if FUSE_IOCTL_UNRESTRICTED is clear, the kernel | |
153 | * automatically initializes in and out iovs by decoding @cmd with | |
154 | * _IOC_* macros and the server is not allowed to request RETRY. This | |
155 | * limits ioctl data transfers to well-formed ioctls and is the forced | |
156 | * behavior for all FUSE servers. | |
157 | */ | |
158 | long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg, | |
159 | unsigned int flags) | |
160 | { | |
161 | struct fuse_file *ff = file->private_data; | |
162 | struct fuse_mount *fm = ff->fm; | |
163 | struct fuse_ioctl_in inarg = { | |
164 | .fh = ff->fh, | |
165 | .cmd = cmd, | |
166 | .arg = arg, | |
167 | .flags = flags | |
168 | }; | |
169 | struct fuse_ioctl_out outarg; | |
170 | struct iovec *iov_page = NULL; | |
171 | struct iovec *in_iov = NULL, *out_iov = NULL; | |
172 | unsigned int in_iovs = 0, out_iovs = 0, max_pages; | |
173 | size_t in_size, out_size, c; | |
174 | ssize_t transferred; | |
175 | int err, i; | |
176 | struct iov_iter ii; | |
177 | struct fuse_args_pages ap = {}; | |
178 | ||
179 | #if BITS_PER_LONG == 32 | |
180 | inarg.flags |= FUSE_IOCTL_32BIT; | |
181 | #else | |
182 | if (flags & FUSE_IOCTL_COMPAT) { | |
183 | inarg.flags |= FUSE_IOCTL_32BIT; | |
83a44a4f | 184 | #ifdef CONFIG_X86_X32_ABI |
9ac29fd3 MS |
185 | if (in_x32_syscall()) |
186 | inarg.flags |= FUSE_IOCTL_COMPAT_X32; | |
187 | #endif | |
188 | } | |
189 | #endif | |
190 | ||
191 | /* assume all the iovs returned by client always fits in a page */ | |
192 | BUILD_BUG_ON(sizeof(struct fuse_ioctl_iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE); | |
193 | ||
194 | err = -ENOMEM; | |
195 | ap.pages = fuse_pages_alloc(fm->fc->max_pages, GFP_KERNEL, &ap.descs); | |
196 | iov_page = (struct iovec *) __get_free_page(GFP_KERNEL); | |
197 | if (!ap.pages || !iov_page) | |
198 | goto out; | |
199 | ||
200 | fuse_page_descs_length_init(ap.descs, 0, fm->fc->max_pages); | |
201 | ||
202 | /* | |
203 | * If restricted, initialize IO parameters as encoded in @cmd. | |
204 | * RETRY from server is not allowed. | |
205 | */ | |
206 | if (!(flags & FUSE_IOCTL_UNRESTRICTED)) { | |
207 | struct iovec *iov = iov_page; | |
208 | ||
209 | iov->iov_base = (void __user *)arg; | |
72227eac | 210 | iov->iov_len = _IOC_SIZE(cmd); |
9ac29fd3 MS |
211 | |
212 | if (_IOC_DIR(cmd) & _IOC_WRITE) { | |
213 | in_iov = iov; | |
214 | in_iovs = 1; | |
215 | } | |
216 | ||
217 | if (_IOC_DIR(cmd) & _IOC_READ) { | |
218 | out_iov = iov; | |
219 | out_iovs = 1; | |
220 | } | |
221 | } | |
222 | ||
223 | retry: | |
224 | inarg.in_size = in_size = iov_length(in_iov, in_iovs); | |
225 | inarg.out_size = out_size = iov_length(out_iov, out_iovs); | |
226 | ||
227 | /* | |
228 | * Out data can be used either for actual out data or iovs, | |
229 | * make sure there always is at least one page. | |
230 | */ | |
231 | out_size = max_t(size_t, out_size, PAGE_SIZE); | |
232 | max_pages = DIV_ROUND_UP(max(in_size, out_size), PAGE_SIZE); | |
233 | ||
234 | /* make sure there are enough buffer pages and init request with them */ | |
235 | err = -ENOMEM; | |
236 | if (max_pages > fm->fc->max_pages) | |
237 | goto out; | |
238 | while (ap.num_pages < max_pages) { | |
239 | ap.pages[ap.num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM); | |
240 | if (!ap.pages[ap.num_pages]) | |
241 | goto out; | |
242 | ap.num_pages++; | |
243 | } | |
244 | ||
245 | ||
246 | /* okay, let's send it to the client */ | |
247 | ap.args.opcode = FUSE_IOCTL; | |
248 | ap.args.nodeid = ff->nodeid; | |
249 | ap.args.in_numargs = 1; | |
250 | ap.args.in_args[0].size = sizeof(inarg); | |
251 | ap.args.in_args[0].value = &inarg; | |
252 | if (in_size) { | |
253 | ap.args.in_numargs++; | |
254 | ap.args.in_args[1].size = in_size; | |
255 | ap.args.in_pages = true; | |
256 | ||
257 | err = -EFAULT; | |
de4eda9d | 258 | iov_iter_init(&ii, ITER_SOURCE, in_iov, in_iovs, in_size); |
9ac29fd3 MS |
259 | for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= ap.num_pages); i++) { |
260 | c = copy_page_from_iter(ap.pages[i], 0, PAGE_SIZE, &ii); | |
261 | if (c != PAGE_SIZE && iov_iter_count(&ii)) | |
262 | goto out; | |
263 | } | |
264 | } | |
265 | ||
266 | ap.args.out_numargs = 2; | |
267 | ap.args.out_args[0].size = sizeof(outarg); | |
268 | ap.args.out_args[0].value = &outarg; | |
269 | ap.args.out_args[1].size = out_size; | |
270 | ap.args.out_pages = true; | |
271 | ap.args.out_argvar = true; | |
272 | ||
02c0cab8 | 273 | transferred = fuse_send_ioctl(fm, &ap.args); |
9ac29fd3 MS |
274 | err = transferred; |
275 | if (transferred < 0) | |
276 | goto out; | |
277 | ||
278 | /* did it ask for retry? */ | |
279 | if (outarg.flags & FUSE_IOCTL_RETRY) { | |
280 | void *vaddr; | |
281 | ||
282 | /* no retry if in restricted mode */ | |
283 | err = -EIO; | |
284 | if (!(flags & FUSE_IOCTL_UNRESTRICTED)) | |
285 | goto out; | |
286 | ||
287 | in_iovs = outarg.in_iovs; | |
288 | out_iovs = outarg.out_iovs; | |
289 | ||
290 | /* | |
291 | * Make sure things are in boundary, separate checks | |
292 | * are to protect against overflow. | |
293 | */ | |
294 | err = -ENOMEM; | |
295 | if (in_iovs > FUSE_IOCTL_MAX_IOV || | |
296 | out_iovs > FUSE_IOCTL_MAX_IOV || | |
297 | in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV) | |
298 | goto out; | |
299 | ||
5fe0fc9f | 300 | vaddr = kmap_local_page(ap.pages[0]); |
9ac29fd3 MS |
301 | err = fuse_copy_ioctl_iovec(fm->fc, iov_page, vaddr, |
302 | transferred, in_iovs + out_iovs, | |
303 | (flags & FUSE_IOCTL_COMPAT) != 0); | |
5fe0fc9f | 304 | kunmap_local(vaddr); |
9ac29fd3 MS |
305 | if (err) |
306 | goto out; | |
307 | ||
308 | in_iov = iov_page; | |
309 | out_iov = in_iov + in_iovs; | |
310 | ||
311 | err = fuse_verify_ioctl_iov(fm->fc, in_iov, in_iovs); | |
312 | if (err) | |
313 | goto out; | |
314 | ||
315 | err = fuse_verify_ioctl_iov(fm->fc, out_iov, out_iovs); | |
316 | if (err) | |
317 | goto out; | |
318 | ||
319 | goto retry; | |
320 | } | |
321 | ||
322 | err = -EIO; | |
323 | if (transferred > inarg.out_size) | |
324 | goto out; | |
325 | ||
326 | err = -EFAULT; | |
de4eda9d | 327 | iov_iter_init(&ii, ITER_DEST, out_iov, out_iovs, transferred); |
9ac29fd3 MS |
328 | for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= ap.num_pages); i++) { |
329 | c = copy_page_to_iter(ap.pages[i], 0, PAGE_SIZE, &ii); | |
330 | if (c != PAGE_SIZE && iov_iter_count(&ii)) | |
331 | goto out; | |
332 | } | |
333 | err = 0; | |
334 | out: | |
335 | free_page((unsigned long) iov_page); | |
336 | while (ap.num_pages) | |
337 | __free_page(ap.pages[--ap.num_pages]); | |
338 | kfree(ap.pages); | |
339 | ||
340 | return err ? err : outarg.result; | |
341 | } | |
342 | EXPORT_SYMBOL_GPL(fuse_do_ioctl); | |
343 | ||
344 | long fuse_ioctl_common(struct file *file, unsigned int cmd, | |
345 | unsigned long arg, unsigned int flags) | |
346 | { | |
347 | struct inode *inode = file_inode(file); | |
348 | struct fuse_conn *fc = get_fuse_conn(inode); | |
349 | ||
350 | if (!fuse_allow_current_process(fc)) | |
351 | return -EACCES; | |
352 | ||
353 | if (fuse_is_bad(inode)) | |
354 | return -EIO; | |
355 | ||
356 | return fuse_do_ioctl(file, cmd, arg, flags); | |
357 | } | |
358 | ||
359 | long fuse_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
360 | { | |
361 | return fuse_ioctl_common(file, cmd, arg, 0); | |
362 | } | |
363 | ||
364 | long fuse_file_compat_ioctl(struct file *file, unsigned int cmd, | |
365 | unsigned long arg) | |
366 | { | |
367 | return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_COMPAT); | |
368 | } | |
72227eac MS |
369 | |
370 | static int fuse_priv_ioctl(struct inode *inode, struct fuse_file *ff, | |
371 | unsigned int cmd, void *ptr, size_t size) | |
372 | { | |
373 | struct fuse_mount *fm = ff->fm; | |
374 | struct fuse_ioctl_in inarg; | |
375 | struct fuse_ioctl_out outarg; | |
376 | FUSE_ARGS(args); | |
377 | int err; | |
378 | ||
379 | memset(&inarg, 0, sizeof(inarg)); | |
380 | inarg.fh = ff->fh; | |
381 | inarg.cmd = cmd; | |
382 | ||
383 | #if BITS_PER_LONG == 32 | |
384 | inarg.flags |= FUSE_IOCTL_32BIT; | |
385 | #endif | |
386 | if (S_ISDIR(inode->i_mode)) | |
387 | inarg.flags |= FUSE_IOCTL_DIR; | |
388 | ||
389 | if (_IOC_DIR(cmd) & _IOC_READ) | |
390 | inarg.out_size = size; | |
391 | if (_IOC_DIR(cmd) & _IOC_WRITE) | |
392 | inarg.in_size = size; | |
393 | ||
394 | args.opcode = FUSE_IOCTL; | |
395 | args.nodeid = ff->nodeid; | |
396 | args.in_numargs = 2; | |
397 | args.in_args[0].size = sizeof(inarg); | |
398 | args.in_args[0].value = &inarg; | |
399 | args.in_args[1].size = inarg.in_size; | |
400 | args.in_args[1].value = ptr; | |
401 | args.out_numargs = 2; | |
402 | args.out_args[0].size = sizeof(outarg); | |
403 | args.out_args[0].value = &outarg; | |
404 | args.out_args[1].size = inarg.out_size; | |
405 | args.out_args[1].value = ptr; | |
406 | ||
02c0cab8 | 407 | err = fuse_send_ioctl(fm, &args); |
a679a615 MS |
408 | if (!err) { |
409 | if (outarg.result < 0) | |
410 | err = outarg.result; | |
411 | else if (outarg.flags & FUSE_IOCTL_RETRY) | |
412 | err = -EIO; | |
413 | } | |
72227eac MS |
414 | return err; |
415 | } | |
416 | ||
417 | static struct fuse_file *fuse_priv_ioctl_prepare(struct inode *inode) | |
418 | { | |
419 | struct fuse_mount *fm = get_fuse_mount(inode); | |
420 | bool isdir = S_ISDIR(inode->i_mode); | |
421 | ||
1cc4606d AM |
422 | if (!fuse_allow_current_process(fm->fc)) |
423 | return ERR_PTR(-EACCES); | |
424 | ||
425 | if (fuse_is_bad(inode)) | |
426 | return ERR_PTR(-EIO); | |
427 | ||
72227eac MS |
428 | if (!S_ISREG(inode->i_mode) && !isdir) |
429 | return ERR_PTR(-ENOTTY); | |
430 | ||
431 | return fuse_file_open(fm, get_node_id(inode), O_RDONLY, isdir); | |
432 | } | |
433 | ||
434 | static void fuse_priv_ioctl_cleanup(struct inode *inode, struct fuse_file *ff) | |
435 | { | |
436 | fuse_file_release(inode, ff, O_RDONLY, NULL, S_ISDIR(inode->i_mode)); | |
437 | } | |
438 | ||
439 | int fuse_fileattr_get(struct dentry *dentry, struct fileattr *fa) | |
440 | { | |
441 | struct inode *inode = d_inode(dentry); | |
442 | struct fuse_file *ff; | |
443 | unsigned int flags; | |
444 | struct fsxattr xfa; | |
445 | int err; | |
446 | ||
447 | ff = fuse_priv_ioctl_prepare(inode); | |
448 | if (IS_ERR(ff)) | |
449 | return PTR_ERR(ff); | |
450 | ||
451 | if (fa->flags_valid) { | |
452 | err = fuse_priv_ioctl(inode, ff, FS_IOC_GETFLAGS, | |
453 | &flags, sizeof(flags)); | |
454 | if (err) | |
455 | goto cleanup; | |
456 | ||
457 | fileattr_fill_flags(fa, flags); | |
458 | } else { | |
459 | err = fuse_priv_ioctl(inode, ff, FS_IOC_FSGETXATTR, | |
460 | &xfa, sizeof(xfa)); | |
461 | if (err) | |
462 | goto cleanup; | |
463 | ||
464 | fileattr_fill_xflags(fa, xfa.fsx_xflags); | |
465 | fa->fsx_extsize = xfa.fsx_extsize; | |
466 | fa->fsx_nextents = xfa.fsx_nextents; | |
467 | fa->fsx_projid = xfa.fsx_projid; | |
468 | fa->fsx_cowextsize = xfa.fsx_cowextsize; | |
469 | } | |
470 | cleanup: | |
471 | fuse_priv_ioctl_cleanup(inode, ff); | |
472 | ||
473 | return err; | |
474 | } | |
475 | ||
8782a9ae | 476 | int fuse_fileattr_set(struct mnt_idmap *idmap, |
72227eac MS |
477 | struct dentry *dentry, struct fileattr *fa) |
478 | { | |
479 | struct inode *inode = d_inode(dentry); | |
480 | struct fuse_file *ff; | |
481 | unsigned int flags = fa->flags; | |
482 | struct fsxattr xfa; | |
483 | int err; | |
484 | ||
485 | ff = fuse_priv_ioctl_prepare(inode); | |
486 | if (IS_ERR(ff)) | |
487 | return PTR_ERR(ff); | |
488 | ||
489 | if (fa->flags_valid) { | |
490 | err = fuse_priv_ioctl(inode, ff, FS_IOC_SETFLAGS, | |
491 | &flags, sizeof(flags)); | |
492 | if (err) | |
493 | goto cleanup; | |
494 | } else { | |
495 | memset(&xfa, 0, sizeof(xfa)); | |
496 | xfa.fsx_xflags = fa->fsx_xflags; | |
497 | xfa.fsx_extsize = fa->fsx_extsize; | |
498 | xfa.fsx_nextents = fa->fsx_nextents; | |
499 | xfa.fsx_projid = fa->fsx_projid; | |
500 | xfa.fsx_cowextsize = fa->fsx_cowextsize; | |
501 | ||
502 | err = fuse_priv_ioctl(inode, ff, FS_IOC_FSSETXATTR, | |
503 | &xfa, sizeof(xfa)); | |
504 | } | |
505 | ||
506 | cleanup: | |
507 | fuse_priv_ioctl_cleanup(inode, ff); | |
508 | ||
509 | return err; | |
510 | } |