statfs.c 9.6 KB

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