Commit | Line | Data |
---|---|---|
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 | ||
6a567e92 MS |
12 | static ssize_t fuse_send_ioctl(struct fuse_mount *fm, struct fuse_args *args, |
13 | struct fuse_ioctl_out *outarg) | |
02c0cab8 | 14 | { |
6a567e92 MS |
15 | ssize_t ret; |
16 | ||
17 | args->out_args[0].size = sizeof(*outarg); | |
18 | args->out_args[0].value = outarg; | |
19 | ||
20 | ret = fuse_simple_request(fm, args); | |
02c0cab8 MS |
21 | |
22 | /* Translate ENOSYS, which shouldn't be returned from fs */ | |
23 | if (ret == -ENOSYS) | |
24 | ret = -ENOTTY; | |
25 | ||
6a567e92 MS |
26 | if (ret >= 0 && outarg->result == -ENOSYS) |
27 | outarg->result = -ENOTTY; | |
28 | ||
02c0cab8 MS |
29 | return ret; |
30 | } | |
31 | ||
9ac29fd3 MS |
32 | /* |
33 | * CUSE servers compiled on 32bit broke on 64bit kernels because the | |
34 | * ABI was defined to be 'struct iovec' which is different on 32bit | |
35 | * and 64bit. Fortunately we can determine which structure the server | |
36 | * used from the size of the reply. | |
37 | */ | |
38 | static int fuse_copy_ioctl_iovec_old(struct iovec *dst, void *src, | |
39 | size_t transferred, unsigned count, | |
40 | bool is_compat) | |
41 | { | |
42 | #ifdef CONFIG_COMPAT | |
43 | if (count * sizeof(struct compat_iovec) == transferred) { | |
44 | struct compat_iovec *ciov = src; | |
45 | unsigned i; | |
46 | ||
47 | /* | |
48 | * With this interface a 32bit server cannot support | |
49 | * non-compat (i.e. ones coming from 64bit apps) ioctl | |
50 | * requests | |
51 | */ | |
52 | if (!is_compat) | |
53 | return -EINVAL; | |
54 | ||
55 | for (i = 0; i < count; i++) { | |
56 | dst[i].iov_base = compat_ptr(ciov[i].iov_base); | |
57 | dst[i].iov_len = ciov[i].iov_len; | |
58 | } | |
59 | return 0; | |
60 | } | |
61 | #endif | |
62 | ||
63 | if (count * sizeof(struct iovec) != transferred) | |
64 | return -EIO; | |
65 | ||
66 | memcpy(dst, src, transferred); | |
67 | return 0; | |
68 | } | |
69 | ||
70 | /* Make sure iov_length() won't overflow */ | |
71 | static int fuse_verify_ioctl_iov(struct fuse_conn *fc, struct iovec *iov, | |
72 | size_t count) | |
73 | { | |
74 | size_t n; | |
75 | u32 max = fc->max_pages << PAGE_SHIFT; | |
76 | ||
77 | for (n = 0; n < count; n++, iov++) { | |
78 | if (iov->iov_len > (size_t) max) | |
79 | return -ENOMEM; | |
80 | max -= iov->iov_len; | |
81 | } | |
82 | return 0; | |
83 | } | |
84 | ||
85 | static int fuse_copy_ioctl_iovec(struct fuse_conn *fc, struct iovec *dst, | |
86 | void *src, size_t transferred, unsigned count, | |
87 | bool is_compat) | |
88 | { | |
89 | unsigned i; | |
90 | struct fuse_ioctl_iovec *fiov = src; | |
91 | ||
92 | if (fc->minor < 16) { | |
93 | return fuse_copy_ioctl_iovec_old(dst, src, transferred, | |
94 | count, is_compat); | |
95 | } | |
96 | ||
97 | if (count * sizeof(struct fuse_ioctl_iovec) != transferred) | |
98 | return -EIO; | |
99 | ||
100 | for (i = 0; i < count; i++) { | |
101 | /* Did the server supply an inappropriate value? */ | |
102 | if (fiov[i].base != (unsigned long) fiov[i].base || | |
103 | fiov[i].len != (unsigned long) fiov[i].len) | |
104 | return -EIO; | |
105 | ||
106 | dst[i].iov_base = (void __user *) (unsigned long) fiov[i].base; | |
107 | dst[i].iov_len = (size_t) fiov[i].len; | |
108 | ||
109 | #ifdef CONFIG_COMPAT | |
110 | if (is_compat && | |
111 | (ptr_to_compat(dst[i].iov_base) != fiov[i].base || | |
112 | (compat_size_t) dst[i].iov_len != fiov[i].len)) | |
113 | return -EIO; | |
114 | #endif | |
115 | } | |
116 | ||
117 | return 0; | |
118 | } | |
119 | ||
120 | ||
121 | /* | |
122 | * For ioctls, there is no generic way to determine how much memory | |
123 | * needs to be read and/or written. Furthermore, ioctls are allowed | |
124 | * to dereference the passed pointer, so the parameter requires deep | |
125 | * copying but FUSE has no idea whatsoever about what to copy in or | |
126 | * out. | |
127 | * | |
128 | * This is solved by allowing FUSE server to retry ioctl with | |
129 | * necessary in/out iovecs. Let's assume the ioctl implementation | |
130 | * needs to read in the following structure. | |
131 | * | |
132 | * struct a { | |
133 | * char *buf; | |
134 | * size_t buflen; | |
135 | * } | |
136 | * | |
137 | * On the first callout to FUSE server, inarg->in_size and | |
138 | * inarg->out_size will be NULL; then, the server completes the ioctl | |
139 | * with FUSE_IOCTL_RETRY set in out->flags, out->in_iovs set to 1 and | |
140 | * the actual iov array to | |
141 | * | |
142 | * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) } } | |
143 | * | |
144 | * which tells FUSE to copy in the requested area and retry the ioctl. | |
145 | * On the second round, the server has access to the structure and | |
146 | * from that it can tell what to look for next, so on the invocation, | |
147 | * it sets FUSE_IOCTL_RETRY, out->in_iovs to 2 and iov array to | |
148 | * | |
149 | * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) }, | |
150 | * { .iov_base = a.buf, .iov_len = a.buflen } } | |
151 | * | |
152 | * FUSE will copy both struct a and the pointed buffer from the | |
153 | * process doing the ioctl and retry ioctl with both struct a and the | |
154 | * buffer. | |
155 | * | |
156 | * This time, FUSE server has everything it needs and completes ioctl | |
157 | * without FUSE_IOCTL_RETRY which finishes the ioctl call. | |
158 | * | |
159 | * Copying data out works the same way. | |
160 | * | |
161 | * Note that if FUSE_IOCTL_UNRESTRICTED is clear, the kernel | |
162 | * automatically initializes in and out iovs by decoding @cmd with | |
163 | * _IOC_* macros and the server is not allowed to request RETRY. This | |
164 | * limits ioctl data transfers to well-formed ioctls and is the forced | |
165 | * behavior for all FUSE servers. | |
166 | */ | |
167 | long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg, | |
168 | unsigned int flags) | |
169 | { | |
170 | struct fuse_file *ff = file->private_data; | |
171 | struct fuse_mount *fm = ff->fm; | |
172 | struct fuse_ioctl_in inarg = { | |
173 | .fh = ff->fh, | |
174 | .cmd = cmd, | |
175 | .arg = arg, | |
176 | .flags = flags | |
177 | }; | |
178 | struct fuse_ioctl_out outarg; | |
179 | struct iovec *iov_page = NULL; | |
180 | struct iovec *in_iov = NULL, *out_iov = NULL; | |
181 | unsigned int in_iovs = 0, out_iovs = 0, max_pages; | |
182 | size_t in_size, out_size, c; | |
183 | ssize_t transferred; | |
184 | int err, i; | |
185 | struct iov_iter ii; | |
186 | struct fuse_args_pages ap = {}; | |
187 | ||
188 | #if BITS_PER_LONG == 32 | |
189 | inarg.flags |= FUSE_IOCTL_32BIT; | |
190 | #else | |
191 | if (flags & FUSE_IOCTL_COMPAT) { | |
192 | inarg.flags |= FUSE_IOCTL_32BIT; | |
83a44a4f | 193 | #ifdef CONFIG_X86_X32_ABI |
9ac29fd3 MS |
194 | if (in_x32_syscall()) |
195 | inarg.flags |= FUSE_IOCTL_COMPAT_X32; | |
196 | #endif | |
197 | } | |
198 | #endif | |
199 | ||
200 | /* assume all the iovs returned by client always fits in a page */ | |
201 | BUILD_BUG_ON(sizeof(struct fuse_ioctl_iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE); | |
202 | ||
203 | err = -ENOMEM; | |
204 | ap.pages = fuse_pages_alloc(fm->fc->max_pages, GFP_KERNEL, &ap.descs); | |
205 | iov_page = (struct iovec *) __get_free_page(GFP_KERNEL); | |
206 | if (!ap.pages || !iov_page) | |
207 | goto out; | |
208 | ||
209 | fuse_page_descs_length_init(ap.descs, 0, fm->fc->max_pages); | |
210 | ||
211 | /* | |
212 | * If restricted, initialize IO parameters as encoded in @cmd. | |
213 | * RETRY from server is not allowed. | |
214 | */ | |
215 | if (!(flags & FUSE_IOCTL_UNRESTRICTED)) { | |
216 | struct iovec *iov = iov_page; | |
217 | ||
218 | iov->iov_base = (void __user *)arg; | |
72227eac | 219 | iov->iov_len = _IOC_SIZE(cmd); |
9ac29fd3 MS |
220 | |
221 | if (_IOC_DIR(cmd) & _IOC_WRITE) { | |
222 | in_iov = iov; | |
223 | in_iovs = 1; | |
224 | } | |
225 | ||
226 | if (_IOC_DIR(cmd) & _IOC_READ) { | |
227 | out_iov = iov; | |
228 | out_iovs = 1; | |
229 | } | |
230 | } | |
231 | ||
232 | retry: | |
233 | inarg.in_size = in_size = iov_length(in_iov, in_iovs); | |
234 | inarg.out_size = out_size = iov_length(out_iov, out_iovs); | |
235 | ||
236 | /* | |
237 | * Out data can be used either for actual out data or iovs, | |
238 | * make sure there always is at least one page. | |
239 | */ | |
240 | out_size = max_t(size_t, out_size, PAGE_SIZE); | |
241 | max_pages = DIV_ROUND_UP(max(in_size, out_size), PAGE_SIZE); | |
242 | ||
243 | /* make sure there are enough buffer pages and init request with them */ | |
244 | err = -ENOMEM; | |
245 | if (max_pages > fm->fc->max_pages) | |
246 | goto out; | |
247 | while (ap.num_pages < max_pages) { | |
248 | ap.pages[ap.num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM); | |
249 | if (!ap.pages[ap.num_pages]) | |
250 | goto out; | |
251 | ap.num_pages++; | |
252 | } | |
253 | ||
254 | ||
255 | /* okay, let's send it to the client */ | |
256 | ap.args.opcode = FUSE_IOCTL; | |
257 | ap.args.nodeid = ff->nodeid; | |
258 | ap.args.in_numargs = 1; | |
259 | ap.args.in_args[0].size = sizeof(inarg); | |
260 | ap.args.in_args[0].value = &inarg; | |
261 | if (in_size) { | |
262 | ap.args.in_numargs++; | |
263 | ap.args.in_args[1].size = in_size; | |
264 | ap.args.in_pages = true; | |
265 | ||
266 | err = -EFAULT; | |
de4eda9d | 267 | iov_iter_init(&ii, ITER_SOURCE, in_iov, in_iovs, in_size); |
9ac29fd3 MS |
268 | for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= ap.num_pages); i++) { |
269 | c = copy_page_from_iter(ap.pages[i], 0, PAGE_SIZE, &ii); | |
270 | if (c != PAGE_SIZE && iov_iter_count(&ii)) | |
271 | goto out; | |
272 | } | |
273 | } | |
274 | ||
275 | ap.args.out_numargs = 2; | |
9ac29fd3 MS |
276 | ap.args.out_args[1].size = out_size; |
277 | ap.args.out_pages = true; | |
278 | ap.args.out_argvar = true; | |
279 | ||
6a567e92 | 280 | transferred = fuse_send_ioctl(fm, &ap.args, &outarg); |
9ac29fd3 MS |
281 | err = transferred; |
282 | if (transferred < 0) | |
283 | goto out; | |
284 | ||
285 | /* did it ask for retry? */ | |
286 | if (outarg.flags & FUSE_IOCTL_RETRY) { | |
287 | void *vaddr; | |
288 | ||
289 | /* no retry if in restricted mode */ | |
290 | err = -EIO; | |
291 | if (!(flags & FUSE_IOCTL_UNRESTRICTED)) | |
292 | goto out; | |
293 | ||
294 | in_iovs = outarg.in_iovs; | |
295 | out_iovs = outarg.out_iovs; | |
296 | ||
297 | /* | |
298 | * Make sure things are in boundary, separate checks | |
299 | * are to protect against overflow. | |
300 | */ | |
301 | err = -ENOMEM; | |
302 | if (in_iovs > FUSE_IOCTL_MAX_IOV || | |
303 | out_iovs > FUSE_IOCTL_MAX_IOV || | |
304 | in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV) | |
305 | goto out; | |
306 | ||
5fe0fc9f | 307 | vaddr = kmap_local_page(ap.pages[0]); |
9ac29fd3 MS |
308 | err = fuse_copy_ioctl_iovec(fm->fc, iov_page, vaddr, |
309 | transferred, in_iovs + out_iovs, | |
310 | (flags & FUSE_IOCTL_COMPAT) != 0); | |
5fe0fc9f | 311 | kunmap_local(vaddr); |
9ac29fd3 MS |
312 | if (err) |
313 | goto out; | |
314 | ||
315 | in_iov = iov_page; | |
316 | out_iov = in_iov + in_iovs; | |
317 | ||
318 | err = fuse_verify_ioctl_iov(fm->fc, in_iov, in_iovs); | |
319 | if (err) | |
320 | goto out; | |
321 | ||
322 | err = fuse_verify_ioctl_iov(fm->fc, out_iov, out_iovs); | |
323 | if (err) | |
324 | goto out; | |
325 | ||
326 | goto retry; | |
327 | } | |
328 | ||
329 | err = -EIO; | |
330 | if (transferred > inarg.out_size) | |
331 | goto out; | |
332 | ||
333 | err = -EFAULT; | |
de4eda9d | 334 | iov_iter_init(&ii, ITER_DEST, out_iov, out_iovs, transferred); |
9ac29fd3 MS |
335 | for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= ap.num_pages); i++) { |
336 | c = copy_page_to_iter(ap.pages[i], 0, PAGE_SIZE, &ii); | |
337 | if (c != PAGE_SIZE && iov_iter_count(&ii)) | |
338 | goto out; | |
339 | } | |
340 | err = 0; | |
341 | out: | |
342 | free_page((unsigned long) iov_page); | |
343 | while (ap.num_pages) | |
344 | __free_page(ap.pages[--ap.num_pages]); | |
345 | kfree(ap.pages); | |
346 | ||
347 | return err ? err : outarg.result; | |
348 | } | |
349 | EXPORT_SYMBOL_GPL(fuse_do_ioctl); | |
350 | ||
351 | long fuse_ioctl_common(struct file *file, unsigned int cmd, | |
352 | unsigned long arg, unsigned int flags) | |
353 | { | |
354 | struct inode *inode = file_inode(file); | |
355 | struct fuse_conn *fc = get_fuse_conn(inode); | |
356 | ||
357 | if (!fuse_allow_current_process(fc)) | |
358 | return -EACCES; | |
359 | ||
360 | if (fuse_is_bad(inode)) | |
361 | return -EIO; | |
362 | ||
363 | return fuse_do_ioctl(file, cmd, arg, flags); | |
364 | } | |
365 | ||
366 | long fuse_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
367 | { | |
368 | return fuse_ioctl_common(file, cmd, arg, 0); | |
369 | } | |
370 | ||
371 | long fuse_file_compat_ioctl(struct file *file, unsigned int cmd, | |
372 | unsigned long arg) | |
373 | { | |
374 | return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_COMPAT); | |
375 | } | |
72227eac MS |
376 | |
377 | static int fuse_priv_ioctl(struct inode *inode, struct fuse_file *ff, | |
378 | unsigned int cmd, void *ptr, size_t size) | |
379 | { | |
380 | struct fuse_mount *fm = ff->fm; | |
381 | struct fuse_ioctl_in inarg; | |
382 | struct fuse_ioctl_out outarg; | |
383 | FUSE_ARGS(args); | |
384 | int err; | |
385 | ||
386 | memset(&inarg, 0, sizeof(inarg)); | |
387 | inarg.fh = ff->fh; | |
388 | inarg.cmd = cmd; | |
389 | ||
390 | #if BITS_PER_LONG == 32 | |
391 | inarg.flags |= FUSE_IOCTL_32BIT; | |
392 | #endif | |
393 | if (S_ISDIR(inode->i_mode)) | |
394 | inarg.flags |= FUSE_IOCTL_DIR; | |
395 | ||
396 | if (_IOC_DIR(cmd) & _IOC_READ) | |
397 | inarg.out_size = size; | |
398 | if (_IOC_DIR(cmd) & _IOC_WRITE) | |
399 | inarg.in_size = size; | |
400 | ||
401 | args.opcode = FUSE_IOCTL; | |
402 | args.nodeid = ff->nodeid; | |
403 | args.in_numargs = 2; | |
404 | args.in_args[0].size = sizeof(inarg); | |
405 | args.in_args[0].value = &inarg; | |
406 | args.in_args[1].size = inarg.in_size; | |
407 | args.in_args[1].value = ptr; | |
408 | args.out_numargs = 2; | |
72227eac MS |
409 | args.out_args[1].size = inarg.out_size; |
410 | args.out_args[1].value = ptr; | |
411 | ||
6a567e92 | 412 | err = fuse_send_ioctl(fm, &args, &outarg); |
a679a615 MS |
413 | if (!err) { |
414 | if (outarg.result < 0) | |
415 | err = outarg.result; | |
416 | else if (outarg.flags & FUSE_IOCTL_RETRY) | |
417 | err = -EIO; | |
418 | } | |
72227eac MS |
419 | return err; |
420 | } | |
421 | ||
422 | static struct fuse_file *fuse_priv_ioctl_prepare(struct inode *inode) | |
423 | { | |
424 | struct fuse_mount *fm = get_fuse_mount(inode); | |
425 | bool isdir = S_ISDIR(inode->i_mode); | |
426 | ||
1cc4606d AM |
427 | if (!fuse_allow_current_process(fm->fc)) |
428 | return ERR_PTR(-EACCES); | |
429 | ||
430 | if (fuse_is_bad(inode)) | |
431 | return ERR_PTR(-EIO); | |
432 | ||
72227eac MS |
433 | if (!S_ISREG(inode->i_mode) && !isdir) |
434 | return ERR_PTR(-ENOTTY); | |
435 | ||
436 | return fuse_file_open(fm, get_node_id(inode), O_RDONLY, isdir); | |
437 | } | |
438 | ||
439 | static void fuse_priv_ioctl_cleanup(struct inode *inode, struct fuse_file *ff) | |
440 | { | |
441 | fuse_file_release(inode, ff, O_RDONLY, NULL, S_ISDIR(inode->i_mode)); | |
442 | } | |
443 | ||
444 | int fuse_fileattr_get(struct dentry *dentry, struct fileattr *fa) | |
445 | { | |
446 | struct inode *inode = d_inode(dentry); | |
447 | struct fuse_file *ff; | |
448 | unsigned int flags; | |
449 | struct fsxattr xfa; | |
450 | int err; | |
451 | ||
452 | ff = fuse_priv_ioctl_prepare(inode); | |
453 | if (IS_ERR(ff)) | |
454 | return PTR_ERR(ff); | |
455 | ||
456 | if (fa->flags_valid) { | |
457 | err = fuse_priv_ioctl(inode, ff, FS_IOC_GETFLAGS, | |
458 | &flags, sizeof(flags)); | |
459 | if (err) | |
460 | goto cleanup; | |
461 | ||
462 | fileattr_fill_flags(fa, flags); | |
463 | } else { | |
464 | err = fuse_priv_ioctl(inode, ff, FS_IOC_FSGETXATTR, | |
465 | &xfa, sizeof(xfa)); | |
466 | if (err) | |
467 | goto cleanup; | |
468 | ||
469 | fileattr_fill_xflags(fa, xfa.fsx_xflags); | |
470 | fa->fsx_extsize = xfa.fsx_extsize; | |
471 | fa->fsx_nextents = xfa.fsx_nextents; | |
472 | fa->fsx_projid = xfa.fsx_projid; | |
473 | fa->fsx_cowextsize = xfa.fsx_cowextsize; | |
474 | } | |
475 | cleanup: | |
476 | fuse_priv_ioctl_cleanup(inode, ff); | |
477 | ||
478 | return err; | |
479 | } | |
480 | ||
8782a9ae | 481 | int fuse_fileattr_set(struct mnt_idmap *idmap, |
72227eac MS |
482 | struct dentry *dentry, struct fileattr *fa) |
483 | { | |
484 | struct inode *inode = d_inode(dentry); | |
485 | struct fuse_file *ff; | |
486 | unsigned int flags = fa->flags; | |
487 | struct fsxattr xfa; | |
488 | int err; | |
489 | ||
490 | ff = fuse_priv_ioctl_prepare(inode); | |
491 | if (IS_ERR(ff)) | |
492 | return PTR_ERR(ff); | |
493 | ||
494 | if (fa->flags_valid) { | |
495 | err = fuse_priv_ioctl(inode, ff, FS_IOC_SETFLAGS, | |
496 | &flags, sizeof(flags)); | |
497 | if (err) | |
498 | goto cleanup; | |
499 | } else { | |
500 | memset(&xfa, 0, sizeof(xfa)); | |
501 | xfa.fsx_xflags = fa->fsx_xflags; | |
502 | xfa.fsx_extsize = fa->fsx_extsize; | |
503 | xfa.fsx_nextents = fa->fsx_nextents; | |
504 | xfa.fsx_projid = fa->fsx_projid; | |
505 | xfa.fsx_cowextsize = fa->fsx_cowextsize; | |
506 | ||
507 | err = fuse_priv_ioctl(inode, ff, FS_IOC_FSSETXATTR, | |
508 | &xfa, sizeof(xfa)); | |
509 | } | |
510 | ||
511 | cleanup: | |
512 | fuse_priv_ioctl_cleanup(inode, ff); | |
513 | ||
514 | return err; | |
515 | } |