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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
14static 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
37static 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
49static int calculate_f_flags(struct vfsmount *mnt)
50{
51 return ST_VALID | flags_by_mnt(mnt->mnt_flags) |
52 flags_by_sb(mnt->mnt_sb->s_flags);
53}
54
55static 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
72int 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, &st);
78 if (error)
79 return error;
80
81 *fsid = st.f_fsid;
82 return 0;
83}
84EXPORT_SYMBOL(vfs_get_fsid);
85
86int vfs_statfs(const struct path *path, struct kstatfs *buf)
87{
88 int error;
89
90 error = statfs_by_dentry(path->dentry, buf);
91 if (!error)
92 buf->f_flags = calculate_f_flags(path->mnt);
93 return error;
94}
95EXPORT_SYMBOL(vfs_statfs);
96
97int 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 CLASS(filename, name)(pathname);
103retry:
104 error = filename_lookup(AT_FDCWD, name, lookup_flags, &path, NULL);
105 if (!error) {
106 error = vfs_statfs(&path, st);
107 path_put(&path);
108 if (retry_estale(error, lookup_flags)) {
109 lookup_flags |= LOOKUP_REVAL;
110 goto retry;
111 }
112 }
113 return error;
114}
115
116int fd_statfs(int fd, struct kstatfs *st)
117{
118 CLASS(fd_raw, f)(fd);
119
120 if (fd_empty(f))
121 return -EBADF;
122 return vfs_statfs(&fd_file(f)->f_path, st);
123}
124
125static int do_statfs_native(struct kstatfs *st, struct statfs __user *p)
126{
127 struct statfs buf;
128
129 if (sizeof(buf) == sizeof(*st))
130 memcpy(&buf, st, sizeof(*st));
131 else {
132 memset(&buf, 0, sizeof(buf));
133 if (sizeof buf.f_blocks == 4) {
134 if ((st->f_blocks | st->f_bfree | st->f_bavail |
135 st->f_bsize | st->f_frsize) &
136 0xffffffff00000000ULL)
137 return -EOVERFLOW;
138 /*
139 * f_files and f_ffree may be -1; it's okay to stuff
140 * that into 32 bits
141 */
142 if (st->f_files != -1 &&
143 (st->f_files & 0xffffffff00000000ULL))
144 return -EOVERFLOW;
145 if (st->f_ffree != -1 &&
146 (st->f_ffree & 0xffffffff00000000ULL))
147 return -EOVERFLOW;
148 }
149
150 buf.f_type = st->f_type;
151 buf.f_bsize = st->f_bsize;
152 buf.f_blocks = st->f_blocks;
153 buf.f_bfree = st->f_bfree;
154 buf.f_bavail = st->f_bavail;
155 buf.f_files = st->f_files;
156 buf.f_ffree = st->f_ffree;
157 buf.f_fsid = st->f_fsid;
158 buf.f_namelen = st->f_namelen;
159 buf.f_frsize = st->f_frsize;
160 buf.f_flags = st->f_flags;
161 }
162 if (copy_to_user(p, &buf, sizeof(buf)))
163 return -EFAULT;
164 return 0;
165}
166
167static int do_statfs64(struct kstatfs *st, struct statfs64 __user *p)
168{
169 struct statfs64 buf;
170 if (sizeof(buf) == sizeof(*st))
171 memcpy(&buf, st, sizeof(*st));
172 else {
173 memset(&buf, 0, sizeof(buf));
174 buf.f_type = st->f_type;
175 buf.f_bsize = st->f_bsize;
176 buf.f_blocks = st->f_blocks;
177 buf.f_bfree = st->f_bfree;
178 buf.f_bavail = st->f_bavail;
179 buf.f_files = st->f_files;
180 buf.f_ffree = st->f_ffree;
181 buf.f_fsid = st->f_fsid;
182 buf.f_namelen = st->f_namelen;
183 buf.f_frsize = st->f_frsize;
184 buf.f_flags = st->f_flags;
185 }
186 if (copy_to_user(p, &buf, sizeof(buf)))
187 return -EFAULT;
188 return 0;
189}
190
191SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct statfs __user *, buf)
192{
193 struct kstatfs st;
194 int error = user_statfs(pathname, &st);
195 if (!error)
196 error = do_statfs_native(&st, buf);
197 return error;
198}
199
200SYSCALL_DEFINE3(statfs64, const char __user *, pathname, size_t, sz, struct statfs64 __user *, buf)
201{
202 struct kstatfs st;
203 int error;
204 if (sz != sizeof(*buf))
205 return -EINVAL;
206 error = user_statfs(pathname, &st);
207 if (!error)
208 error = do_statfs64(&st, buf);
209 return error;
210}
211
212SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct statfs __user *, buf)
213{
214 struct kstatfs st;
215 int error = fd_statfs(fd, &st);
216 if (!error)
217 error = do_statfs_native(&st, buf);
218 return error;
219}
220
221SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user *, buf)
222{
223 struct kstatfs st;
224 int error;
225
226 if (sz != sizeof(*buf))
227 return -EINVAL;
228
229 error = fd_statfs(fd, &st);
230 if (!error)
231 error = do_statfs64(&st, buf);
232 return error;
233}
234
235static int vfs_ustat(dev_t dev, struct kstatfs *sbuf)
236{
237 struct super_block *s = user_get_super(dev, false);
238 int err;
239 if (!s)
240 return -EINVAL;
241
242 err = statfs_by_dentry(s->s_root, sbuf);
243 drop_super(s);
244 return err;
245}
246
247SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf)
248{
249 struct ustat tmp;
250 struct kstatfs sbuf;
251 int err = vfs_ustat(new_decode_dev(dev), &sbuf);
252 if (err)
253 return err;
254
255 memset(&tmp,0,sizeof(struct ustat));
256 tmp.f_tfree = sbuf.f_bfree;
257 if (IS_ENABLED(CONFIG_ARCH_32BIT_USTAT_F_TINODE))
258 tmp.f_tinode = min_t(u64, sbuf.f_ffree, UINT_MAX);
259 else
260 tmp.f_tinode = sbuf.f_ffree;
261
262 return copy_to_user(ubuf, &tmp, sizeof(struct ustat)) ? -EFAULT : 0;
263}
264
265#ifdef CONFIG_COMPAT
266static int put_compat_statfs(struct compat_statfs __user *ubuf, struct kstatfs *kbuf)
267{
268 struct compat_statfs buf;
269 if (sizeof ubuf->f_blocks == 4) {
270 if ((kbuf->f_blocks | kbuf->f_bfree | kbuf->f_bavail |
271 kbuf->f_bsize | kbuf->f_frsize) & 0xffffffff00000000ULL)
272 return -EOVERFLOW;
273 /* f_files and f_ffree may be -1; it's okay
274 * to stuff that into 32 bits */
275 if (kbuf->f_files != 0xffffffffffffffffULL
276 && (kbuf->f_files & 0xffffffff00000000ULL))
277 return -EOVERFLOW;
278 if (kbuf->f_ffree != 0xffffffffffffffffULL
279 && (kbuf->f_ffree & 0xffffffff00000000ULL))
280 return -EOVERFLOW;
281 }
282 memset(&buf, 0, sizeof(struct compat_statfs));
283 buf.f_type = kbuf->f_type;
284 buf.f_bsize = kbuf->f_bsize;
285 buf.f_blocks = kbuf->f_blocks;
286 buf.f_bfree = kbuf->f_bfree;
287 buf.f_bavail = kbuf->f_bavail;
288 buf.f_files = kbuf->f_files;
289 buf.f_ffree = kbuf->f_ffree;
290 buf.f_namelen = kbuf->f_namelen;
291 buf.f_fsid.val[0] = kbuf->f_fsid.val[0];
292 buf.f_fsid.val[1] = kbuf->f_fsid.val[1];
293 buf.f_frsize = kbuf->f_frsize;
294 buf.f_flags = kbuf->f_flags;
295 if (copy_to_user(ubuf, &buf, sizeof(struct compat_statfs)))
296 return -EFAULT;
297 return 0;
298}
299
300/*
301 * The following statfs calls are copies of code from fs/statfs.c and
302 * should be checked against those from time to time
303 */
304COMPAT_SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct compat_statfs __user *, buf)
305{
306 struct kstatfs tmp;
307 int error = user_statfs(pathname, &tmp);
308 if (!error)
309 error = put_compat_statfs(buf, &tmp);
310 return error;
311}
312
313COMPAT_SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct compat_statfs __user *, buf)
314{
315 struct kstatfs tmp;
316 int error = fd_statfs(fd, &tmp);
317 if (!error)
318 error = put_compat_statfs(buf, &tmp);
319 return error;
320}
321
322static int put_compat_statfs64(struct compat_statfs64 __user *ubuf, struct kstatfs *kbuf)
323{
324 struct compat_statfs64 buf;
325
326 if ((kbuf->f_bsize | kbuf->f_frsize) & 0xffffffff00000000ULL)
327 return -EOVERFLOW;
328
329 memset(&buf, 0, sizeof(struct compat_statfs64));
330 buf.f_type = kbuf->f_type;
331 buf.f_bsize = kbuf->f_bsize;
332 buf.f_blocks = kbuf->f_blocks;
333 buf.f_bfree = kbuf->f_bfree;
334 buf.f_bavail = kbuf->f_bavail;
335 buf.f_files = kbuf->f_files;
336 buf.f_ffree = kbuf->f_ffree;
337 buf.f_namelen = kbuf->f_namelen;
338 buf.f_fsid.val[0] = kbuf->f_fsid.val[0];
339 buf.f_fsid.val[1] = kbuf->f_fsid.val[1];
340 buf.f_frsize = kbuf->f_frsize;
341 buf.f_flags = kbuf->f_flags;
342 if (copy_to_user(ubuf, &buf, sizeof(struct compat_statfs64)))
343 return -EFAULT;
344 return 0;
345}
346
347int kcompat_sys_statfs64(const char __user * pathname, compat_size_t sz, struct compat_statfs64 __user * buf)
348{
349 struct kstatfs tmp;
350 int error;
351
352 if (sz != sizeof(*buf))
353 return -EINVAL;
354
355 error = user_statfs(pathname, &tmp);
356 if (!error)
357 error = put_compat_statfs64(buf, &tmp);
358 return error;
359}
360
361COMPAT_SYSCALL_DEFINE3(statfs64, const char __user *, pathname, compat_size_t, sz, struct compat_statfs64 __user *, buf)
362{
363 return kcompat_sys_statfs64(pathname, sz, buf);
364}
365
366int kcompat_sys_fstatfs64(unsigned int fd, compat_size_t sz, struct compat_statfs64 __user * buf)
367{
368 struct kstatfs tmp;
369 int error;
370
371 if (sz != sizeof(*buf))
372 return -EINVAL;
373
374 error = fd_statfs(fd, &tmp);
375 if (!error)
376 error = put_compat_statfs64(buf, &tmp);
377 return error;
378}
379
380COMPAT_SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, compat_size_t, sz, struct compat_statfs64 __user *, buf)
381{
382 return kcompat_sys_fstatfs64(fd, sz, buf);
383}
384
385/*
386 * This is a copy of sys_ustat, just dealing with a structure layout.
387 * Given how simple this syscall is that apporach is more maintainable
388 * than the various conversion hacks.
389 */
390COMPAT_SYSCALL_DEFINE2(ustat, unsigned, dev, struct compat_ustat __user *, u)
391{
392 struct compat_ustat tmp;
393 struct kstatfs sbuf;
394 int err = vfs_ustat(new_decode_dev(dev), &sbuf);
395 if (err)
396 return err;
397
398 memset(&tmp, 0, sizeof(struct compat_ustat));
399 tmp.f_tfree = sbuf.f_bfree;
400 tmp.f_tinode = sbuf.f_ffree;
401 if (copy_to_user(u, &tmp, sizeof(struct compat_ustat)))
402 return -EFAULT;
403 return 0;
404}
405#endif