1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/fs/stat.c
4  *
5  *  Copyright (C) 1991, 1992  Linus Torvalds
6  */
7 
8 #include <linux/export.h>
9 #include <linux/mm.h>
10 #include <linux/errno.h>
11 #include <linux/file.h>
12 #include <linux/highuid.h>
13 #include <linux/fs.h>
14 #include <linux/namei.h>
15 #include <linux/security.h>
16 #include <linux/cred.h>
17 #include <linux/syscalls.h>
18 #include <linux/pagemap.h>
19 #include <linux/compat.h>
20 
21 #include <linux/uaccess.h>
22 #include <asm/unistd.h>
23 
24 #include "internal.h"
25 #include "mount.h"
26 
27 /**
28  * generic_fillattr - Fill in the basic attributes from the inode struct
29  * @mnt_userns:	user namespace of the mount the inode was found from
30  * @inode:	Inode to use as the source
31  * @stat:	Where to fill in the attributes
32  *
33  * Fill in the basic attributes in the kstat structure from data that's to be
34  * found on the VFS inode structure.  This is the default if no getattr inode
35  * operation is supplied.
36  *
37  * If the inode has been found through an idmapped mount the user namespace of
38  * the vfsmount must be passed through @mnt_userns. This function will then
39  * take care to map the inode according to @mnt_userns before filling in the
40  * uid and gid filds. On non-idmapped mounts or if permission checking is to be
41  * performed on the raw inode simply passs init_user_ns.
42  */
generic_fillattr(struct user_namespace * mnt_userns,struct inode * inode,struct kstat * stat)43 void generic_fillattr(struct user_namespace *mnt_userns, struct inode *inode,
44 		      struct kstat *stat)
45 {
46 	stat->dev = inode->i_sb->s_dev;
47 	stat->ino = inode->i_ino;
48 	stat->mode = inode->i_mode;
49 	stat->nlink = inode->i_nlink;
50 	stat->uid = i_uid_into_mnt(mnt_userns, inode);
51 	stat->gid = i_gid_into_mnt(mnt_userns, inode);
52 	stat->rdev = inode->i_rdev;
53 	stat->size = i_size_read(inode);
54 	stat->atime = inode->i_atime;
55 	stat->mtime = inode->i_mtime;
56 	stat->ctime = inode->i_ctime;
57 	stat->blksize = i_blocksize(inode);
58 	stat->blocks = inode->i_blocks;
59 }
60 EXPORT_SYMBOL(generic_fillattr);
61 
62 /**
63  * generic_fill_statx_attr - Fill in the statx attributes from the inode flags
64  * @inode:	Inode to use as the source
65  * @stat:	Where to fill in the attribute flags
66  *
67  * Fill in the STATX_ATTR_* flags in the kstat structure for properties of the
68  * inode that are published on i_flags and enforced by the VFS.
69  */
generic_fill_statx_attr(struct inode * inode,struct kstat * stat)70 void generic_fill_statx_attr(struct inode *inode, struct kstat *stat)
71 {
72 	if (inode->i_flags & S_IMMUTABLE)
73 		stat->attributes |= STATX_ATTR_IMMUTABLE;
74 	if (inode->i_flags & S_APPEND)
75 		stat->attributes |= STATX_ATTR_APPEND;
76 	stat->attributes_mask |= KSTAT_ATTR_VFS_FLAGS;
77 }
78 EXPORT_SYMBOL(generic_fill_statx_attr);
79 
80 /**
81  * vfs_getattr_nosec - getattr without security checks
82  * @path: file to get attributes from
83  * @stat: structure to return attributes in
84  * @request_mask: STATX_xxx flags indicating what the caller wants
85  * @query_flags: Query mode (AT_STATX_SYNC_TYPE)
86  *
87  * Get attributes without calling security_inode_getattr.
88  *
89  * Currently the only caller other than vfs_getattr is internal to the
90  * filehandle lookup code, which uses only the inode number and returns no
91  * attributes to any user.  Any other code probably wants vfs_getattr.
92  */
vfs_getattr_nosec(const struct path * path,struct kstat * stat,u32 request_mask,unsigned int query_flags)93 int vfs_getattr_nosec(const struct path *path, struct kstat *stat,
94 		      u32 request_mask, unsigned int query_flags)
95 {
96 	struct user_namespace *mnt_userns;
97 	struct inode *inode = d_backing_inode(path->dentry);
98 
99 	memset(stat, 0, sizeof(*stat));
100 	stat->result_mask |= STATX_BASIC_STATS;
101 	query_flags &= AT_STATX_SYNC_TYPE;
102 
103 	/* allow the fs to override these if it really wants to */
104 	/* SB_NOATIME means filesystem supplies dummy atime value */
105 	if (inode->i_sb->s_flags & SB_NOATIME)
106 		stat->result_mask &= ~STATX_ATIME;
107 
108 	/*
109 	 * Note: If you add another clause to set an attribute flag, please
110 	 * update attributes_mask below.
111 	 */
112 	if (IS_AUTOMOUNT(inode))
113 		stat->attributes |= STATX_ATTR_AUTOMOUNT;
114 
115 	if (IS_DAX(inode))
116 		stat->attributes |= STATX_ATTR_DAX;
117 
118 	stat->attributes_mask |= (STATX_ATTR_AUTOMOUNT |
119 				  STATX_ATTR_DAX);
120 
121 	mnt_userns = mnt_user_ns(path->mnt);
122 	if (inode->i_op->getattr)
123 		return inode->i_op->getattr(mnt_userns, path, stat,
124 					    request_mask, query_flags);
125 
126 	generic_fillattr(mnt_userns, inode, stat);
127 	return 0;
128 }
129 EXPORT_SYMBOL(vfs_getattr_nosec);
130 
131 /*
132  * vfs_getattr - Get the enhanced basic attributes of a file
133  * @path: The file of interest
134  * @stat: Where to return the statistics
135  * @request_mask: STATX_xxx flags indicating what the caller wants
136  * @query_flags: Query mode (AT_STATX_SYNC_TYPE)
137  *
138  * Ask the filesystem for a file's attributes.  The caller must indicate in
139  * request_mask and query_flags to indicate what they want.
140  *
141  * If the file is remote, the filesystem can be forced to update the attributes
142  * from the backing store by passing AT_STATX_FORCE_SYNC in query_flags or can
143  * suppress the update by passing AT_STATX_DONT_SYNC.
144  *
145  * Bits must have been set in request_mask to indicate which attributes the
146  * caller wants retrieving.  Any such attribute not requested may be returned
147  * anyway, but the value may be approximate, and, if remote, may not have been
148  * synchronised with the server.
149  *
150  * 0 will be returned on success, and a -ve error code if unsuccessful.
151  */
vfs_getattr(const struct path * path,struct kstat * stat,u32 request_mask,unsigned int query_flags)152 int vfs_getattr(const struct path *path, struct kstat *stat,
153 		u32 request_mask, unsigned int query_flags)
154 {
155 	int retval;
156 
157 	retval = security_inode_getattr(path);
158 	if (retval)
159 		return retval;
160 	return vfs_getattr_nosec(path, stat, request_mask, query_flags);
161 }
162 EXPORT_SYMBOL(vfs_getattr);
163 
164 /**
165  * vfs_fstat - Get the basic attributes by file descriptor
166  * @fd: The file descriptor referring to the file of interest
167  * @stat: The result structure to fill in.
168  *
169  * This function is a wrapper around vfs_getattr().  The main difference is
170  * that it uses a file descriptor to determine the file location.
171  *
172  * 0 will be returned on success, and a -ve error code if unsuccessful.
173  */
vfs_fstat(int fd,struct kstat * stat)174 int vfs_fstat(int fd, struct kstat *stat)
175 {
176 	struct fd f;
177 	int error;
178 
179 	f = fdget_raw(fd);
180 	if (!f.file)
181 		return -EBADF;
182 	error = vfs_getattr(&f.file->f_path, stat, STATX_BASIC_STATS, 0);
183 	fdput(f);
184 	return error;
185 }
186 
getname_statx_lookup_flags(int flags)187 int getname_statx_lookup_flags(int flags)
188 {
189 	int lookup_flags = 0;
190 
191 	if (!(flags & AT_SYMLINK_NOFOLLOW))
192 		lookup_flags |= LOOKUP_FOLLOW;
193 	if (!(flags & AT_NO_AUTOMOUNT))
194 		lookup_flags |= LOOKUP_AUTOMOUNT;
195 	if (flags & AT_EMPTY_PATH)
196 		lookup_flags |= LOOKUP_EMPTY;
197 
198 	return lookup_flags;
199 }
200 
201 /**
202  * vfs_statx - Get basic and extra attributes by filename
203  * @dfd: A file descriptor representing the base dir for a relative filename
204  * @filename: The name of the file of interest
205  * @flags: Flags to control the query
206  * @stat: The result structure to fill in.
207  * @request_mask: STATX_xxx flags indicating what the caller wants
208  *
209  * This function is a wrapper around vfs_getattr().  The main difference is
210  * that it uses a filename and base directory to determine the file location.
211  * Additionally, the use of AT_SYMLINK_NOFOLLOW in flags will prevent a symlink
212  * at the given name from being referenced.
213  *
214  * 0 will be returned on success, and a -ve error code if unsuccessful.
215  */
vfs_statx(int dfd,struct filename * filename,int flags,struct kstat * stat,u32 request_mask)216 static int vfs_statx(int dfd, struct filename *filename, int flags,
217 	      struct kstat *stat, u32 request_mask)
218 {
219 	struct path path;
220 	unsigned int lookup_flags = getname_statx_lookup_flags(flags);
221 	int error;
222 
223 	if (flags & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT | AT_EMPTY_PATH |
224 		      AT_STATX_SYNC_TYPE))
225 		return -EINVAL;
226 
227 retry:
228 	error = filename_lookup(dfd, filename, lookup_flags, &path, NULL);
229 	if (error)
230 		goto out;
231 
232 	error = vfs_getattr(&path, stat, request_mask, flags);
233 	stat->mnt_id = real_mount(path.mnt)->mnt_id;
234 	stat->result_mask |= STATX_MNT_ID;
235 	if (path.mnt->mnt_root == path.dentry)
236 		stat->attributes |= STATX_ATTR_MOUNT_ROOT;
237 	stat->attributes_mask |= STATX_ATTR_MOUNT_ROOT;
238 	path_put(&path);
239 	if (retry_estale(error, lookup_flags)) {
240 		lookup_flags |= LOOKUP_REVAL;
241 		goto retry;
242 	}
243 out:
244 	return error;
245 }
246 
vfs_fstatat(int dfd,const char __user * filename,struct kstat * stat,int flags)247 int vfs_fstatat(int dfd, const char __user *filename,
248 			      struct kstat *stat, int flags)
249 {
250 	int ret;
251 	int statx_flags = flags | AT_NO_AUTOMOUNT;
252 	struct filename *name;
253 
254 	name = getname_flags(filename, getname_statx_lookup_flags(statx_flags), NULL);
255 	ret = vfs_statx(dfd, name, statx_flags, stat, STATX_BASIC_STATS);
256 	putname(name);
257 
258 	return ret;
259 }
260 
261 #ifdef __ARCH_WANT_OLD_STAT
262 
263 /*
264  * For backward compatibility?  Maybe this should be moved
265  * into arch/i386 instead?
266  */
cp_old_stat(struct kstat * stat,struct __old_kernel_stat __user * statbuf)267 static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
268 {
269 	static int warncount = 5;
270 	struct __old_kernel_stat tmp;
271 
272 	if (warncount > 0) {
273 		warncount--;
274 		printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
275 			current->comm);
276 	} else if (warncount < 0) {
277 		/* it's laughable, but... */
278 		warncount = 0;
279 	}
280 
281 	memset(&tmp, 0, sizeof(struct __old_kernel_stat));
282 	tmp.st_dev = old_encode_dev(stat->dev);
283 	tmp.st_ino = stat->ino;
284 	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
285 		return -EOVERFLOW;
286 	tmp.st_mode = stat->mode;
287 	tmp.st_nlink = stat->nlink;
288 	if (tmp.st_nlink != stat->nlink)
289 		return -EOVERFLOW;
290 	SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
291 	SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
292 	tmp.st_rdev = old_encode_dev(stat->rdev);
293 #if BITS_PER_LONG == 32
294 	if (stat->size > MAX_NON_LFS)
295 		return -EOVERFLOW;
296 #endif
297 	tmp.st_size = stat->size;
298 	tmp.st_atime = stat->atime.tv_sec;
299 	tmp.st_mtime = stat->mtime.tv_sec;
300 	tmp.st_ctime = stat->ctime.tv_sec;
301 	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
302 }
303 
SYSCALL_DEFINE2(stat,const char __user *,filename,struct __old_kernel_stat __user *,statbuf)304 SYSCALL_DEFINE2(stat, const char __user *, filename,
305 		struct __old_kernel_stat __user *, statbuf)
306 {
307 	struct kstat stat;
308 	int error;
309 
310 	error = vfs_stat(filename, &stat);
311 	if (error)
312 		return error;
313 
314 	return cp_old_stat(&stat, statbuf);
315 }
316 
SYSCALL_DEFINE2(lstat,const char __user *,filename,struct __old_kernel_stat __user *,statbuf)317 SYSCALL_DEFINE2(lstat, const char __user *, filename,
318 		struct __old_kernel_stat __user *, statbuf)
319 {
320 	struct kstat stat;
321 	int error;
322 
323 	error = vfs_lstat(filename, &stat);
324 	if (error)
325 		return error;
326 
327 	return cp_old_stat(&stat, statbuf);
328 }
329 
SYSCALL_DEFINE2(fstat,unsigned int,fd,struct __old_kernel_stat __user *,statbuf)330 SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf)
331 {
332 	struct kstat stat;
333 	int error = vfs_fstat(fd, &stat);
334 
335 	if (!error)
336 		error = cp_old_stat(&stat, statbuf);
337 
338 	return error;
339 }
340 
341 #endif /* __ARCH_WANT_OLD_STAT */
342 
343 #ifdef __ARCH_WANT_NEW_STAT
344 
345 #if BITS_PER_LONG == 32
346 #  define choose_32_64(a,b) a
347 #else
348 #  define choose_32_64(a,b) b
349 #endif
350 
351 #ifndef INIT_STRUCT_STAT_PADDING
352 #  define INIT_STRUCT_STAT_PADDING(st) memset(&st, 0, sizeof(st))
353 #endif
354 
cp_new_stat(struct kstat * stat,struct stat __user * statbuf)355 static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
356 {
357 	struct stat tmp;
358 
359 	if (sizeof(tmp.st_dev) < 4 && !old_valid_dev(stat->dev))
360 		return -EOVERFLOW;
361 	if (sizeof(tmp.st_rdev) < 4 && !old_valid_dev(stat->rdev))
362 		return -EOVERFLOW;
363 #if BITS_PER_LONG == 32
364 	if (stat->size > MAX_NON_LFS)
365 		return -EOVERFLOW;
366 #endif
367 
368 	INIT_STRUCT_STAT_PADDING(tmp);
369 	tmp.st_dev = new_encode_dev(stat->dev);
370 	tmp.st_ino = stat->ino;
371 	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
372 		return -EOVERFLOW;
373 	tmp.st_mode = stat->mode;
374 	tmp.st_nlink = stat->nlink;
375 	if (tmp.st_nlink != stat->nlink)
376 		return -EOVERFLOW;
377 	SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
378 	SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
379 	tmp.st_rdev = new_encode_dev(stat->rdev);
380 	tmp.st_size = stat->size;
381 	tmp.st_atime = stat->atime.tv_sec;
382 	tmp.st_mtime = stat->mtime.tv_sec;
383 	tmp.st_ctime = stat->ctime.tv_sec;
384 #ifdef STAT_HAVE_NSEC
385 	tmp.st_atime_nsec = stat->atime.tv_nsec;
386 	tmp.st_mtime_nsec = stat->mtime.tv_nsec;
387 	tmp.st_ctime_nsec = stat->ctime.tv_nsec;
388 #endif
389 	tmp.st_blocks = stat->blocks;
390 	tmp.st_blksize = stat->blksize;
391 	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
392 }
393 
SYSCALL_DEFINE2(newstat,const char __user *,filename,struct stat __user *,statbuf)394 SYSCALL_DEFINE2(newstat, const char __user *, filename,
395 		struct stat __user *, statbuf)
396 {
397 	struct kstat stat;
398 	int error = vfs_stat(filename, &stat);
399 
400 	if (error)
401 		return error;
402 	return cp_new_stat(&stat, statbuf);
403 }
404 
SYSCALL_DEFINE2(newlstat,const char __user *,filename,struct stat __user *,statbuf)405 SYSCALL_DEFINE2(newlstat, const char __user *, filename,
406 		struct stat __user *, statbuf)
407 {
408 	struct kstat stat;
409 	int error;
410 
411 	error = vfs_lstat(filename, &stat);
412 	if (error)
413 		return error;
414 
415 	return cp_new_stat(&stat, statbuf);
416 }
417 
418 #if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)
SYSCALL_DEFINE4(newfstatat,int,dfd,const char __user *,filename,struct stat __user *,statbuf,int,flag)419 SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename,
420 		struct stat __user *, statbuf, int, flag)
421 {
422 	struct kstat stat;
423 	int error;
424 
425 	error = vfs_fstatat(dfd, filename, &stat, flag);
426 	if (error)
427 		return error;
428 	return cp_new_stat(&stat, statbuf);
429 }
430 #endif
431 
SYSCALL_DEFINE2(newfstat,unsigned int,fd,struct stat __user *,statbuf)432 SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
433 {
434 	struct kstat stat;
435 	int error = vfs_fstat(fd, &stat);
436 
437 	if (!error)
438 		error = cp_new_stat(&stat, statbuf);
439 
440 	return error;
441 }
442 #endif
443 
do_readlinkat(int dfd,const char __user * pathname,char __user * buf,int bufsiz)444 static int do_readlinkat(int dfd, const char __user *pathname,
445 			 char __user *buf, int bufsiz)
446 {
447 	struct path path;
448 	int error;
449 	int empty = 0;
450 	unsigned int lookup_flags = LOOKUP_EMPTY;
451 
452 	if (bufsiz <= 0)
453 		return -EINVAL;
454 
455 retry:
456 	error = user_path_at_empty(dfd, pathname, lookup_flags, &path, &empty);
457 	if (!error) {
458 		struct inode *inode = d_backing_inode(path.dentry);
459 
460 		error = empty ? -ENOENT : -EINVAL;
461 		/*
462 		 * AFS mountpoints allow readlink(2) but are not symlinks
463 		 */
464 		if (d_is_symlink(path.dentry) || inode->i_op->readlink) {
465 			error = security_inode_readlink(path.dentry);
466 			if (!error) {
467 				touch_atime(&path);
468 				error = vfs_readlink(path.dentry, buf, bufsiz);
469 			}
470 		}
471 		path_put(&path);
472 		if (retry_estale(error, lookup_flags)) {
473 			lookup_flags |= LOOKUP_REVAL;
474 			goto retry;
475 		}
476 	}
477 	return error;
478 }
479 
SYSCALL_DEFINE4(readlinkat,int,dfd,const char __user *,pathname,char __user *,buf,int,bufsiz)480 SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
481 		char __user *, buf, int, bufsiz)
482 {
483 	return do_readlinkat(dfd, pathname, buf, bufsiz);
484 }
485 
SYSCALL_DEFINE3(readlink,const char __user *,path,char __user *,buf,int,bufsiz)486 SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,
487 		int, bufsiz)
488 {
489 	return do_readlinkat(AT_FDCWD, path, buf, bufsiz);
490 }
491 
492 
493 /* ---------- LFS-64 ----------- */
494 #if defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_COMPAT_STAT64)
495 
496 #ifndef INIT_STRUCT_STAT64_PADDING
497 #  define INIT_STRUCT_STAT64_PADDING(st) memset(&st, 0, sizeof(st))
498 #endif
499 
cp_new_stat64(struct kstat * stat,struct stat64 __user * statbuf)500 static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
501 {
502 	struct stat64 tmp;
503 
504 	INIT_STRUCT_STAT64_PADDING(tmp);
505 #ifdef CONFIG_MIPS
506 	/* mips has weird padding, so we don't get 64 bits there */
507 	tmp.st_dev = new_encode_dev(stat->dev);
508 	tmp.st_rdev = new_encode_dev(stat->rdev);
509 #else
510 	tmp.st_dev = huge_encode_dev(stat->dev);
511 	tmp.st_rdev = huge_encode_dev(stat->rdev);
512 #endif
513 	tmp.st_ino = stat->ino;
514 	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
515 		return -EOVERFLOW;
516 #ifdef STAT64_HAS_BROKEN_ST_INO
517 	tmp.__st_ino = stat->ino;
518 #endif
519 	tmp.st_mode = stat->mode;
520 	tmp.st_nlink = stat->nlink;
521 	tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
522 	tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
523 	tmp.st_atime = stat->atime.tv_sec;
524 	tmp.st_atime_nsec = stat->atime.tv_nsec;
525 	tmp.st_mtime = stat->mtime.tv_sec;
526 	tmp.st_mtime_nsec = stat->mtime.tv_nsec;
527 	tmp.st_ctime = stat->ctime.tv_sec;
528 	tmp.st_ctime_nsec = stat->ctime.tv_nsec;
529 	tmp.st_size = stat->size;
530 	tmp.st_blocks = stat->blocks;
531 	tmp.st_blksize = stat->blksize;
532 	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
533 }
534 
SYSCALL_DEFINE2(stat64,const char __user *,filename,struct stat64 __user *,statbuf)535 SYSCALL_DEFINE2(stat64, const char __user *, filename,
536 		struct stat64 __user *, statbuf)
537 {
538 	struct kstat stat;
539 	int error = vfs_stat(filename, &stat);
540 
541 	if (!error)
542 		error = cp_new_stat64(&stat, statbuf);
543 
544 	return error;
545 }
546 
SYSCALL_DEFINE2(lstat64,const char __user *,filename,struct stat64 __user *,statbuf)547 SYSCALL_DEFINE2(lstat64, const char __user *, filename,
548 		struct stat64 __user *, statbuf)
549 {
550 	struct kstat stat;
551 	int error = vfs_lstat(filename, &stat);
552 
553 	if (!error)
554 		error = cp_new_stat64(&stat, statbuf);
555 
556 	return error;
557 }
558 
SYSCALL_DEFINE2(fstat64,unsigned long,fd,struct stat64 __user *,statbuf)559 SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf)
560 {
561 	struct kstat stat;
562 	int error = vfs_fstat(fd, &stat);
563 
564 	if (!error)
565 		error = cp_new_stat64(&stat, statbuf);
566 
567 	return error;
568 }
569 
SYSCALL_DEFINE4(fstatat64,int,dfd,const char __user *,filename,struct stat64 __user *,statbuf,int,flag)570 SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
571 		struct stat64 __user *, statbuf, int, flag)
572 {
573 	struct kstat stat;
574 	int error;
575 
576 	error = vfs_fstatat(dfd, filename, &stat, flag);
577 	if (error)
578 		return error;
579 	return cp_new_stat64(&stat, statbuf);
580 }
581 #endif /* __ARCH_WANT_STAT64 || __ARCH_WANT_COMPAT_STAT64 */
582 
583 static noinline_for_stack int
cp_statx(const struct kstat * stat,struct statx __user * buffer)584 cp_statx(const struct kstat *stat, struct statx __user *buffer)
585 {
586 	struct statx tmp;
587 
588 	memset(&tmp, 0, sizeof(tmp));
589 
590 	tmp.stx_mask = stat->result_mask;
591 	tmp.stx_blksize = stat->blksize;
592 	tmp.stx_attributes = stat->attributes;
593 	tmp.stx_nlink = stat->nlink;
594 	tmp.stx_uid = from_kuid_munged(current_user_ns(), stat->uid);
595 	tmp.stx_gid = from_kgid_munged(current_user_ns(), stat->gid);
596 	tmp.stx_mode = stat->mode;
597 	tmp.stx_ino = stat->ino;
598 	tmp.stx_size = stat->size;
599 	tmp.stx_blocks = stat->blocks;
600 	tmp.stx_attributes_mask = stat->attributes_mask;
601 	tmp.stx_atime.tv_sec = stat->atime.tv_sec;
602 	tmp.stx_atime.tv_nsec = stat->atime.tv_nsec;
603 	tmp.stx_btime.tv_sec = stat->btime.tv_sec;
604 	tmp.stx_btime.tv_nsec = stat->btime.tv_nsec;
605 	tmp.stx_ctime.tv_sec = stat->ctime.tv_sec;
606 	tmp.stx_ctime.tv_nsec = stat->ctime.tv_nsec;
607 	tmp.stx_mtime.tv_sec = stat->mtime.tv_sec;
608 	tmp.stx_mtime.tv_nsec = stat->mtime.tv_nsec;
609 	tmp.stx_rdev_major = MAJOR(stat->rdev);
610 	tmp.stx_rdev_minor = MINOR(stat->rdev);
611 	tmp.stx_dev_major = MAJOR(stat->dev);
612 	tmp.stx_dev_minor = MINOR(stat->dev);
613 	tmp.stx_mnt_id = stat->mnt_id;
614 
615 	return copy_to_user(buffer, &tmp, sizeof(tmp)) ? -EFAULT : 0;
616 }
617 
do_statx(int dfd,struct filename * filename,unsigned int flags,unsigned int mask,struct statx __user * buffer)618 int do_statx(int dfd, struct filename *filename, unsigned int flags,
619 	     unsigned int mask, struct statx __user *buffer)
620 {
621 	struct kstat stat;
622 	int error;
623 
624 	if (mask & STATX__RESERVED)
625 		return -EINVAL;
626 	if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE)
627 		return -EINVAL;
628 
629 	error = vfs_statx(dfd, filename, flags, &stat, mask);
630 	if (error)
631 		return error;
632 
633 	return cp_statx(&stat, buffer);
634 }
635 
636 /**
637  * sys_statx - System call to get enhanced stats
638  * @dfd: Base directory to pathwalk from *or* fd to stat.
639  * @filename: File to stat or "" with AT_EMPTY_PATH
640  * @flags: AT_* flags to control pathwalk.
641  * @mask: Parts of statx struct actually required.
642  * @buffer: Result buffer.
643  *
644  * Note that fstat() can be emulated by setting dfd to the fd of interest,
645  * supplying "" as the filename and setting AT_EMPTY_PATH in the flags.
646  */
SYSCALL_DEFINE5(statx,int,dfd,const char __user *,filename,unsigned,flags,unsigned int,mask,struct statx __user *,buffer)647 SYSCALL_DEFINE5(statx,
648 		int, dfd, const char __user *, filename, unsigned, flags,
649 		unsigned int, mask,
650 		struct statx __user *, buffer)
651 {
652 	int ret;
653 	struct filename *name;
654 
655 	name = getname_flags(filename, getname_statx_lookup_flags(flags), NULL);
656 	ret = do_statx(dfd, name, flags, mask, buffer);
657 	putname(name);
658 
659 	return ret;
660 }
661 
662 #if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_STAT)
cp_compat_stat(struct kstat * stat,struct compat_stat __user * ubuf)663 static int cp_compat_stat(struct kstat *stat, struct compat_stat __user *ubuf)
664 {
665 	struct compat_stat tmp;
666 
667 	if (sizeof(tmp.st_dev) < 4 && !old_valid_dev(stat->dev))
668 		return -EOVERFLOW;
669 	if (sizeof(tmp.st_rdev) < 4 && !old_valid_dev(stat->rdev))
670 		return -EOVERFLOW;
671 
672 	memset(&tmp, 0, sizeof(tmp));
673 	tmp.st_dev = new_encode_dev(stat->dev);
674 	tmp.st_ino = stat->ino;
675 	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
676 		return -EOVERFLOW;
677 	tmp.st_mode = stat->mode;
678 	tmp.st_nlink = stat->nlink;
679 	if (tmp.st_nlink != stat->nlink)
680 		return -EOVERFLOW;
681 	SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
682 	SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
683 	tmp.st_rdev = new_encode_dev(stat->rdev);
684 	if ((u64) stat->size > MAX_NON_LFS)
685 		return -EOVERFLOW;
686 	tmp.st_size = stat->size;
687 	tmp.st_atime = stat->atime.tv_sec;
688 	tmp.st_atime_nsec = stat->atime.tv_nsec;
689 	tmp.st_mtime = stat->mtime.tv_sec;
690 	tmp.st_mtime_nsec = stat->mtime.tv_nsec;
691 	tmp.st_ctime = stat->ctime.tv_sec;
692 	tmp.st_ctime_nsec = stat->ctime.tv_nsec;
693 	tmp.st_blocks = stat->blocks;
694 	tmp.st_blksize = stat->blksize;
695 	return copy_to_user(ubuf, &tmp, sizeof(tmp)) ? -EFAULT : 0;
696 }
697 
COMPAT_SYSCALL_DEFINE2(newstat,const char __user *,filename,struct compat_stat __user *,statbuf)698 COMPAT_SYSCALL_DEFINE2(newstat, const char __user *, filename,
699 		       struct compat_stat __user *, statbuf)
700 {
701 	struct kstat stat;
702 	int error;
703 
704 	error = vfs_stat(filename, &stat);
705 	if (error)
706 		return error;
707 	return cp_compat_stat(&stat, statbuf);
708 }
709 
COMPAT_SYSCALL_DEFINE2(newlstat,const char __user *,filename,struct compat_stat __user *,statbuf)710 COMPAT_SYSCALL_DEFINE2(newlstat, const char __user *, filename,
711 		       struct compat_stat __user *, statbuf)
712 {
713 	struct kstat stat;
714 	int error;
715 
716 	error = vfs_lstat(filename, &stat);
717 	if (error)
718 		return error;
719 	return cp_compat_stat(&stat, statbuf);
720 }
721 
722 #ifndef __ARCH_WANT_STAT64
COMPAT_SYSCALL_DEFINE4(newfstatat,unsigned int,dfd,const char __user *,filename,struct compat_stat __user *,statbuf,int,flag)723 COMPAT_SYSCALL_DEFINE4(newfstatat, unsigned int, dfd,
724 		       const char __user *, filename,
725 		       struct compat_stat __user *, statbuf, int, flag)
726 {
727 	struct kstat stat;
728 	int error;
729 
730 	error = vfs_fstatat(dfd, filename, &stat, flag);
731 	if (error)
732 		return error;
733 	return cp_compat_stat(&stat, statbuf);
734 }
735 #endif
736 
COMPAT_SYSCALL_DEFINE2(newfstat,unsigned int,fd,struct compat_stat __user *,statbuf)737 COMPAT_SYSCALL_DEFINE2(newfstat, unsigned int, fd,
738 		       struct compat_stat __user *, statbuf)
739 {
740 	struct kstat stat;
741 	int error = vfs_fstat(fd, &stat);
742 
743 	if (!error)
744 		error = cp_compat_stat(&stat, statbuf);
745 	return error;
746 }
747 #endif
748 
749 /* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
__inode_add_bytes(struct inode * inode,loff_t bytes)750 void __inode_add_bytes(struct inode *inode, loff_t bytes)
751 {
752 	inode->i_blocks += bytes >> 9;
753 	bytes &= 511;
754 	inode->i_bytes += bytes;
755 	if (inode->i_bytes >= 512) {
756 		inode->i_blocks++;
757 		inode->i_bytes -= 512;
758 	}
759 }
760 EXPORT_SYMBOL(__inode_add_bytes);
761 
inode_add_bytes(struct inode * inode,loff_t bytes)762 void inode_add_bytes(struct inode *inode, loff_t bytes)
763 {
764 	spin_lock(&inode->i_lock);
765 	__inode_add_bytes(inode, bytes);
766 	spin_unlock(&inode->i_lock);
767 }
768 
769 EXPORT_SYMBOL(inode_add_bytes);
770 
__inode_sub_bytes(struct inode * inode,loff_t bytes)771 void __inode_sub_bytes(struct inode *inode, loff_t bytes)
772 {
773 	inode->i_blocks -= bytes >> 9;
774 	bytes &= 511;
775 	if (inode->i_bytes < bytes) {
776 		inode->i_blocks--;
777 		inode->i_bytes += 512;
778 	}
779 	inode->i_bytes -= bytes;
780 }
781 
782 EXPORT_SYMBOL(__inode_sub_bytes);
783 
inode_sub_bytes(struct inode * inode,loff_t bytes)784 void inode_sub_bytes(struct inode *inode, loff_t bytes)
785 {
786 	spin_lock(&inode->i_lock);
787 	__inode_sub_bytes(inode, bytes);
788 	spin_unlock(&inode->i_lock);
789 }
790 
791 EXPORT_SYMBOL(inode_sub_bytes);
792 
inode_get_bytes(struct inode * inode)793 loff_t inode_get_bytes(struct inode *inode)
794 {
795 	loff_t ret;
796 
797 	spin_lock(&inode->i_lock);
798 	ret = __inode_get_bytes(inode);
799 	spin_unlock(&inode->i_lock);
800 	return ret;
801 }
802 
803 EXPORT_SYMBOL(inode_get_bytes);
804 
inode_set_bytes(struct inode * inode,loff_t bytes)805 void inode_set_bytes(struct inode *inode, loff_t bytes)
806 {
807 	/* Caller is here responsible for sufficient locking
808 	 * (ie. inode->i_lock) */
809 	inode->i_blocks = bytes >> 9;
810 	inode->i_bytes = bytes & 511;
811 }
812 
813 EXPORT_SYMBOL(inode_set_bytes);
814