1 | // SPDX-License-Identifier: GPL-2.0 |
2 | #include <linux/syscalls.h> |
3 | #include <linux/export.h> |
4 | #include <linux/fs.h> |
5 | #include <linux/file.h> |
6 | #include <linux/mount.h> |
7 | #include <linux/namei.h> |
8 | #include <linux/statfs.h> |
9 | #include <linux/security.h> |
10 | #include <linux/uaccess.h> |
11 | #include <linux/compat.h> |
12 | #include "internal.h" |
13 | |
14 | static int flags_by_mnt(int mnt_flags) |
15 | { |
16 | int flags = 0; |
17 | |
18 | if (mnt_flags & MNT_READONLY) |
19 | flags |= ST_RDONLY; |
20 | if (mnt_flags & MNT_NOSUID) |
21 | flags |= ST_NOSUID; |
22 | if (mnt_flags & MNT_NODEV) |
23 | flags |= ST_NODEV; |
24 | if (mnt_flags & MNT_NOEXEC) |
25 | flags |= ST_NOEXEC; |
26 | if (mnt_flags & MNT_NOATIME) |
27 | flags |= ST_NOATIME; |
28 | if (mnt_flags & MNT_NODIRATIME) |
29 | flags |= ST_NODIRATIME; |
30 | if (mnt_flags & MNT_RELATIME) |
31 | flags |= ST_RELATIME; |
32 | if (mnt_flags & MNT_NOSYMFOLLOW) |
33 | flags |= ST_NOSYMFOLLOW; |
34 | return flags; |
35 | } |
36 | |
37 | static int flags_by_sb(int s_flags) |
38 | { |
39 | int flags = 0; |
40 | if (s_flags & SB_SYNCHRONOUS) |
41 | flags |= ST_SYNCHRONOUS; |
42 | if (s_flags & SB_MANDLOCK) |
43 | flags |= ST_MANDLOCK; |
44 | if (s_flags & SB_RDONLY) |
45 | flags |= ST_RDONLY; |
46 | return flags; |
47 | } |
48 | |
49 | static int calculate_f_flags(struct vfsmount *mnt) |
50 | { |
51 | return ST_VALID | flags_by_mnt(mnt_flags: mnt->mnt_flags) | |
52 | flags_by_sb(s_flags: mnt->mnt_sb->s_flags); |
53 | } |
54 | |
55 | static int statfs_by_dentry(struct dentry *dentry, struct kstatfs *buf) |
56 | { |
57 | int retval; |
58 | |
59 | if (!dentry->d_sb->s_op->statfs) |
60 | return -ENOSYS; |
61 | |
62 | memset(buf, 0, sizeof(*buf)); |
63 | retval = security_sb_statfs(dentry); |
64 | if (retval) |
65 | return retval; |
66 | retval = dentry->d_sb->s_op->statfs(dentry, buf); |
67 | if (retval == 0 && buf->f_frsize == 0) |
68 | buf->f_frsize = buf->f_bsize; |
69 | return retval; |
70 | } |
71 | |
72 | int vfs_get_fsid(struct dentry *dentry, __kernel_fsid_t *fsid) |
73 | { |
74 | struct kstatfs st; |
75 | int error; |
76 | |
77 | error = statfs_by_dentry(dentry, buf: &st); |
78 | if (error) |
79 | return error; |
80 | |
81 | *fsid = st.f_fsid; |
82 | return 0; |
83 | } |
84 | EXPORT_SYMBOL(vfs_get_fsid); |
85 | |
86 | int vfs_statfs(const struct path *path, struct kstatfs *buf) |
87 | { |
88 | int error; |
89 | |
90 | error = statfs_by_dentry(dentry: path->dentry, buf); |
91 | if (!error) |
92 | buf->f_flags = calculate_f_flags(mnt: path->mnt); |
93 | return error; |
94 | } |
95 | EXPORT_SYMBOL(vfs_statfs); |
96 | |
97 | int user_statfs(const char __user *pathname, struct kstatfs *st) |
98 | { |
99 | struct path path; |
100 | int error; |
101 | unsigned int lookup_flags = LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT; |
102 | retry: |
103 | error = user_path_at(AT_FDCWD, name: pathname, flags: lookup_flags, path: &path); |
104 | if (!error) { |
105 | error = vfs_statfs(&path, st); |
106 | path_put(&path); |
107 | if (retry_estale(error, flags: lookup_flags)) { |
108 | lookup_flags |= LOOKUP_REVAL; |
109 | goto retry; |
110 | } |
111 | } |
112 | return error; |
113 | } |
114 | |
115 | int fd_statfs(int fd, struct kstatfs *st) |
116 | { |
117 | struct fd f = fdget_raw(fd); |
118 | int error = -EBADF; |
119 | if (f.file) { |
120 | error = vfs_statfs(&f.file->f_path, st); |
121 | fdput(fd: f); |
122 | } |
123 | return error; |
124 | } |
125 | |
126 | static int do_statfs_native(struct kstatfs *st, struct statfs __user *p) |
127 | { |
128 | struct statfs buf; |
129 | |
130 | if (sizeof(buf) == sizeof(*st)) |
131 | memcpy(&buf, st, sizeof(*st)); |
132 | else { |
133 | memset(&buf, 0, sizeof(buf)); |
134 | if (sizeof buf.f_blocks == 4) { |
135 | if ((st->f_blocks | st->f_bfree | st->f_bavail | |
136 | st->f_bsize | st->f_frsize) & |
137 | 0xffffffff00000000ULL) |
138 | return -EOVERFLOW; |
139 | /* |
140 | * f_files and f_ffree may be -1; it's okay to stuff |
141 | * that into 32 bits |
142 | */ |
143 | if (st->f_files != -1 && |
144 | (st->f_files & 0xffffffff00000000ULL)) |
145 | return -EOVERFLOW; |
146 | if (st->f_ffree != -1 && |
147 | (st->f_ffree & 0xffffffff00000000ULL)) |
148 | return -EOVERFLOW; |
149 | } |
150 | |
151 | buf.f_type = st->f_type; |
152 | buf.f_bsize = st->f_bsize; |
153 | buf.f_blocks = st->f_blocks; |
154 | buf.f_bfree = st->f_bfree; |
155 | buf.f_bavail = st->f_bavail; |
156 | buf.f_files = st->f_files; |
157 | buf.f_ffree = st->f_ffree; |
158 | buf.f_fsid = st->f_fsid; |
159 | buf.f_namelen = st->f_namelen; |
160 | buf.f_frsize = st->f_frsize; |
161 | buf.f_flags = st->f_flags; |
162 | } |
163 | if (copy_to_user(to: p, from: &buf, n: sizeof(buf))) |
164 | return -EFAULT; |
165 | return 0; |
166 | } |
167 | |
168 | static int do_statfs64(struct kstatfs *st, struct statfs64 __user *p) |
169 | { |
170 | struct statfs64 buf; |
171 | if (sizeof(buf) == sizeof(*st)) |
172 | memcpy(&buf, st, sizeof(*st)); |
173 | else { |
174 | memset(&buf, 0, sizeof(buf)); |
175 | buf.f_type = st->f_type; |
176 | buf.f_bsize = st->f_bsize; |
177 | buf.f_blocks = st->f_blocks; |
178 | buf.f_bfree = st->f_bfree; |
179 | buf.f_bavail = st->f_bavail; |
180 | buf.f_files = st->f_files; |
181 | buf.f_ffree = st->f_ffree; |
182 | buf.f_fsid = st->f_fsid; |
183 | buf.f_namelen = st->f_namelen; |
184 | buf.f_frsize = st->f_frsize; |
185 | buf.f_flags = st->f_flags; |
186 | } |
187 | if (copy_to_user(to: p, from: &buf, n: sizeof(buf))) |
188 | return -EFAULT; |
189 | return 0; |
190 | } |
191 | |
192 | SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct statfs __user *, buf) |
193 | { |
194 | struct kstatfs st; |
195 | int error = user_statfs(pathname, st: &st); |
196 | if (!error) |
197 | error = do_statfs_native(st: &st, p: buf); |
198 | return error; |
199 | } |
200 | |
201 | SYSCALL_DEFINE3(statfs64, const char __user *, pathname, size_t, sz, struct statfs64 __user *, buf) |
202 | { |
203 | struct kstatfs st; |
204 | int error; |
205 | if (sz != sizeof(*buf)) |
206 | return -EINVAL; |
207 | error = user_statfs(pathname, st: &st); |
208 | if (!error) |
209 | error = do_statfs64(st: &st, p: buf); |
210 | return error; |
211 | } |
212 | |
213 | SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct statfs __user *, buf) |
214 | { |
215 | struct kstatfs st; |
216 | int error = fd_statfs(fd, st: &st); |
217 | if (!error) |
218 | error = do_statfs_native(st: &st, p: buf); |
219 | return error; |
220 | } |
221 | |
222 | SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user *, buf) |
223 | { |
224 | struct kstatfs st; |
225 | int error; |
226 | |
227 | if (sz != sizeof(*buf)) |
228 | return -EINVAL; |
229 | |
230 | error = fd_statfs(fd, st: &st); |
231 | if (!error) |
232 | error = do_statfs64(st: &st, p: buf); |
233 | return error; |
234 | } |
235 | |
236 | static int vfs_ustat(dev_t dev, struct kstatfs *sbuf) |
237 | { |
238 | struct super_block *s = user_get_super(dev, excl: false); |
239 | int err; |
240 | if (!s) |
241 | return -EINVAL; |
242 | |
243 | err = statfs_by_dentry(dentry: s->s_root, buf: sbuf); |
244 | drop_super(sb: s); |
245 | return err; |
246 | } |
247 | |
248 | SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf) |
249 | { |
250 | struct ustat tmp; |
251 | struct kstatfs sbuf; |
252 | int err = vfs_ustat(dev: new_decode_dev(dev), sbuf: &sbuf); |
253 | if (err) |
254 | return err; |
255 | |
256 | memset(&tmp,0,sizeof(struct ustat)); |
257 | tmp.f_tfree = sbuf.f_bfree; |
258 | if (IS_ENABLED(CONFIG_ARCH_32BIT_USTAT_F_TINODE)) |
259 | tmp.f_tinode = min_t(u64, sbuf.f_ffree, UINT_MAX); |
260 | else |
261 | tmp.f_tinode = sbuf.f_ffree; |
262 | |
263 | return copy_to_user(to: ubuf, from: &tmp, n: sizeof(struct ustat)) ? -EFAULT : 0; |
264 | } |
265 | |
266 | #ifdef CONFIG_COMPAT |
267 | static int put_compat_statfs(struct compat_statfs __user *ubuf, struct kstatfs *kbuf) |
268 | { |
269 | struct compat_statfs buf; |
270 | if (sizeof ubuf->f_blocks == 4) { |
271 | if ((kbuf->f_blocks | kbuf->f_bfree | kbuf->f_bavail | |
272 | kbuf->f_bsize | kbuf->f_frsize) & 0xffffffff00000000ULL) |
273 | return -EOVERFLOW; |
274 | /* f_files and f_ffree may be -1; it's okay |
275 | * to stuff that into 32 bits */ |
276 | if (kbuf->f_files != 0xffffffffffffffffULL |
277 | && (kbuf->f_files & 0xffffffff00000000ULL)) |
278 | return -EOVERFLOW; |
279 | if (kbuf->f_ffree != 0xffffffffffffffffULL |
280 | && (kbuf->f_ffree & 0xffffffff00000000ULL)) |
281 | return -EOVERFLOW; |
282 | } |
283 | memset(&buf, 0, sizeof(struct compat_statfs)); |
284 | buf.f_type = kbuf->f_type; |
285 | buf.f_bsize = kbuf->f_bsize; |
286 | buf.f_blocks = kbuf->f_blocks; |
287 | buf.f_bfree = kbuf->f_bfree; |
288 | buf.f_bavail = kbuf->f_bavail; |
289 | buf.f_files = kbuf->f_files; |
290 | buf.f_ffree = kbuf->f_ffree; |
291 | buf.f_namelen = kbuf->f_namelen; |
292 | buf.f_fsid.val[0] = kbuf->f_fsid.val[0]; |
293 | buf.f_fsid.val[1] = kbuf->f_fsid.val[1]; |
294 | buf.f_frsize = kbuf->f_frsize; |
295 | buf.f_flags = kbuf->f_flags; |
296 | if (copy_to_user(to: ubuf, from: &buf, n: sizeof(struct compat_statfs))) |
297 | return -EFAULT; |
298 | return 0; |
299 | } |
300 | |
301 | /* |
302 | * The following statfs calls are copies of code from fs/statfs.c and |
303 | * should be checked against those from time to time |
304 | */ |
305 | COMPAT_SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct compat_statfs __user *, buf) |
306 | { |
307 | struct kstatfs tmp; |
308 | int error = user_statfs(pathname, st: &tmp); |
309 | if (!error) |
310 | error = put_compat_statfs(ubuf: buf, kbuf: &tmp); |
311 | return error; |
312 | } |
313 | |
314 | COMPAT_SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct compat_statfs __user *, buf) |
315 | { |
316 | struct kstatfs tmp; |
317 | int error = fd_statfs(fd, st: &tmp); |
318 | if (!error) |
319 | error = put_compat_statfs(ubuf: buf, kbuf: &tmp); |
320 | return error; |
321 | } |
322 | |
323 | static int put_compat_statfs64(struct compat_statfs64 __user *ubuf, struct kstatfs *kbuf) |
324 | { |
325 | struct compat_statfs64 buf; |
326 | |
327 | if ((kbuf->f_bsize | kbuf->f_frsize) & 0xffffffff00000000ULL) |
328 | return -EOVERFLOW; |
329 | |
330 | memset(&buf, 0, sizeof(struct compat_statfs64)); |
331 | buf.f_type = kbuf->f_type; |
332 | buf.f_bsize = kbuf->f_bsize; |
333 | buf.f_blocks = kbuf->f_blocks; |
334 | buf.f_bfree = kbuf->f_bfree; |
335 | buf.f_bavail = kbuf->f_bavail; |
336 | buf.f_files = kbuf->f_files; |
337 | buf.f_ffree = kbuf->f_ffree; |
338 | buf.f_namelen = kbuf->f_namelen; |
339 | buf.f_fsid.val[0] = kbuf->f_fsid.val[0]; |
340 | buf.f_fsid.val[1] = kbuf->f_fsid.val[1]; |
341 | buf.f_frsize = kbuf->f_frsize; |
342 | buf.f_flags = kbuf->f_flags; |
343 | if (copy_to_user(to: ubuf, from: &buf, n: sizeof(struct compat_statfs64))) |
344 | return -EFAULT; |
345 | return 0; |
346 | } |
347 | |
348 | int kcompat_sys_statfs64(const char __user * pathname, compat_size_t sz, struct compat_statfs64 __user * buf) |
349 | { |
350 | struct kstatfs tmp; |
351 | int error; |
352 | |
353 | if (sz != sizeof(*buf)) |
354 | return -EINVAL; |
355 | |
356 | error = user_statfs(pathname, st: &tmp); |
357 | if (!error) |
358 | error = put_compat_statfs64(ubuf: buf, kbuf: &tmp); |
359 | return error; |
360 | } |
361 | |
362 | COMPAT_SYSCALL_DEFINE3(statfs64, const char __user *, pathname, compat_size_t, sz, struct compat_statfs64 __user *, buf) |
363 | { |
364 | return kcompat_sys_statfs64(pathname, sz, buf); |
365 | } |
366 | |
367 | int kcompat_sys_fstatfs64(unsigned int fd, compat_size_t sz, struct compat_statfs64 __user * buf) |
368 | { |
369 | struct kstatfs tmp; |
370 | int error; |
371 | |
372 | if (sz != sizeof(*buf)) |
373 | return -EINVAL; |
374 | |
375 | error = fd_statfs(fd, st: &tmp); |
376 | if (!error) |
377 | error = put_compat_statfs64(ubuf: buf, kbuf: &tmp); |
378 | return error; |
379 | } |
380 | |
381 | COMPAT_SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, compat_size_t, sz, struct compat_statfs64 __user *, buf) |
382 | { |
383 | return kcompat_sys_fstatfs64(fd, sz, buf); |
384 | } |
385 | |
386 | /* |
387 | * This is a copy of sys_ustat, just dealing with a structure layout. |
388 | * Given how simple this syscall is that apporach is more maintainable |
389 | * than the various conversion hacks. |
390 | */ |
391 | COMPAT_SYSCALL_DEFINE2(ustat, unsigned, dev, struct compat_ustat __user *, u) |
392 | { |
393 | struct compat_ustat tmp; |
394 | struct kstatfs sbuf; |
395 | int err = vfs_ustat(dev: new_decode_dev(dev), sbuf: &sbuf); |
396 | if (err) |
397 | return err; |
398 | |
399 | memset(&tmp, 0, sizeof(struct compat_ustat)); |
400 | tmp.f_tfree = sbuf.f_bfree; |
401 | tmp.f_tinode = sbuf.f_ffree; |
402 | if (copy_to_user(to: u, from: &tmp, n: sizeof(struct compat_ustat))) |
403 | return -EFAULT; |
404 | return 0; |
405 | } |
406 | #endif |
407 | |