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