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TOMOYO Linux Cross Reference
Linux/fs/ioctl.c

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  1 // SPDX-License-Identifier: GPL-2.0
  2 /*
  3  *  linux/fs/ioctl.c
  4  *
  5  *  Copyright (C) 1991, 1992  Linus Torvalds
  6  */
  7 
  8 #include <linux/syscalls.h>
  9 #include <linux/mm.h>
 10 #include <linux/capability.h>
 11 #include <linux/compat.h>
 12 #include <linux/file.h>
 13 #include <linux/fs.h>
 14 #include <linux/security.h>
 15 #include <linux/export.h>
 16 #include <linux/uaccess.h>
 17 #include <linux/writeback.h>
 18 #include <linux/buffer_head.h>
 19 #include <linux/falloc.h>
 20 #include <linux/sched/signal.h>
 21 #include <linux/fiemap.h>
 22 #include <linux/mount.h>
 23 #include <linux/fscrypt.h>
 24 #include <linux/fileattr.h>
 25 
 26 #include "internal.h"
 27 
 28 #include <asm/ioctls.h>
 29 
 30 /* So that the fiemap access checks can't overflow on 32 bit machines. */
 31 #define FIEMAP_MAX_EXTENTS      (UINT_MAX / sizeof(struct fiemap_extent))
 32 
 33 /**
 34  * vfs_ioctl - call filesystem specific ioctl methods
 35  * @filp:       open file to invoke ioctl method on
 36  * @cmd:        ioctl command to execute
 37  * @arg:        command-specific argument for ioctl
 38  *
 39  * Invokes filesystem specific ->unlocked_ioctl, if one exists; otherwise
 40  * returns -ENOTTY.
 41  *
 42  * Returns 0 on success, -errno on error.
 43  */
 44 long vfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 45 {
 46         int error = -ENOTTY;
 47 
 48         if (!filp->f_op->unlocked_ioctl)
 49                 goto out;
 50 
 51         error = filp->f_op->unlocked_ioctl(filp, cmd, arg);
 52         if (error == -ENOIOCTLCMD)
 53                 error = -ENOTTY;
 54  out:
 55         return error;
 56 }
 57 EXPORT_SYMBOL(vfs_ioctl);
 58 
 59 static int ioctl_fibmap(struct file *filp, int __user *p)
 60 {
 61         struct inode *inode = file_inode(filp);
 62         struct super_block *sb = inode->i_sb;
 63         int error, ur_block;
 64         sector_t block;
 65 
 66         if (!capable(CAP_SYS_RAWIO))
 67                 return -EPERM;
 68 
 69         error = get_user(ur_block, p);
 70         if (error)
 71                 return error;
 72 
 73         if (ur_block < 0)
 74                 return -EINVAL;
 75 
 76         block = ur_block;
 77         error = bmap(inode, &block);
 78 
 79         if (block > INT_MAX) {
 80                 error = -ERANGE;
 81                 pr_warn_ratelimited("[%s/%d] FS: %s File: %pD4 would truncate fibmap result\n",
 82                                     current->comm, task_pid_nr(current),
 83                                     sb->s_id, filp);
 84         }
 85 
 86         if (error)
 87                 ur_block = 0;
 88         else
 89                 ur_block = block;
 90 
 91         if (put_user(ur_block, p))
 92                 error = -EFAULT;
 93 
 94         return error;
 95 }
 96 
 97 /**
 98  * fiemap_fill_next_extent - Fiemap helper function
 99  * @fieinfo:    Fiemap context passed into ->fiemap
100  * @logical:    Extent logical start offset, in bytes
101  * @phys:       Extent physical start offset, in bytes
102  * @len:        Extent length, in bytes
103  * @flags:      FIEMAP_EXTENT flags that describe this extent
104  *
105  * Called from file system ->fiemap callback. Will populate extent
106  * info as passed in via arguments and copy to user memory. On
107  * success, extent count on fieinfo is incremented.
108  *
109  * Returns 0 on success, -errno on error, 1 if this was the last
110  * extent that will fit in user array.
111  */
112 int fiemap_fill_next_extent(struct fiemap_extent_info *fieinfo, u64 logical,
113                             u64 phys, u64 len, u32 flags)
114 {
115         struct fiemap_extent extent;
116         struct fiemap_extent __user *dest = fieinfo->fi_extents_start;
117 
118         /* only count the extents */
119         if (fieinfo->fi_extents_max == 0) {
120                 fieinfo->fi_extents_mapped++;
121                 return (flags & FIEMAP_EXTENT_LAST) ? 1 : 0;
122         }
123 
124         if (fieinfo->fi_extents_mapped >= fieinfo->fi_extents_max)
125                 return 1;
126 
127 #define SET_UNKNOWN_FLAGS       (FIEMAP_EXTENT_DELALLOC)
128 #define SET_NO_UNMOUNTED_IO_FLAGS       (FIEMAP_EXTENT_DATA_ENCRYPTED)
129 #define SET_NOT_ALIGNED_FLAGS   (FIEMAP_EXTENT_DATA_TAIL|FIEMAP_EXTENT_DATA_INLINE)
130 
131         if (flags & SET_UNKNOWN_FLAGS)
132                 flags |= FIEMAP_EXTENT_UNKNOWN;
133         if (flags & SET_NO_UNMOUNTED_IO_FLAGS)
134                 flags |= FIEMAP_EXTENT_ENCODED;
135         if (flags & SET_NOT_ALIGNED_FLAGS)
136                 flags |= FIEMAP_EXTENT_NOT_ALIGNED;
137 
138         memset(&extent, 0, sizeof(extent));
139         extent.fe_logical = logical;
140         extent.fe_physical = phys;
141         extent.fe_length = len;
142         extent.fe_flags = flags;
143 
144         dest += fieinfo->fi_extents_mapped;
145         if (copy_to_user(dest, &extent, sizeof(extent)))
146                 return -EFAULT;
147 
148         fieinfo->fi_extents_mapped++;
149         if (fieinfo->fi_extents_mapped == fieinfo->fi_extents_max)
150                 return 1;
151         return (flags & FIEMAP_EXTENT_LAST) ? 1 : 0;
152 }
153 EXPORT_SYMBOL(fiemap_fill_next_extent);
154 
155 /**
156  * fiemap_prep - check validity of requested flags for fiemap
157  * @inode:      Inode to operate on
158  * @fieinfo:    Fiemap context passed into ->fiemap
159  * @start:      Start of the mapped range
160  * @len:        Length of the mapped range, can be truncated by this function.
161  * @supported_flags:    Set of fiemap flags that the file system understands
162  *
163  * This function must be called from each ->fiemap instance to validate the
164  * fiemap request against the file system parameters.
165  *
166  * Returns 0 on success, or a negative error on failure.
167  */
168 int fiemap_prep(struct inode *inode, struct fiemap_extent_info *fieinfo,
169                 u64 start, u64 *len, u32 supported_flags)
170 {
171         u64 maxbytes = inode->i_sb->s_maxbytes;
172         u32 incompat_flags;
173         int ret = 0;
174 
175         if (*len == 0)
176                 return -EINVAL;
177         if (start >= maxbytes)
178                 return -EFBIG;
179 
180         /*
181          * Shrink request scope to what the fs can actually handle.
182          */
183         if (*len > maxbytes || (maxbytes - *len) < start)
184                 *len = maxbytes - start;
185 
186         supported_flags |= FIEMAP_FLAG_SYNC;
187         supported_flags &= FIEMAP_FLAGS_COMPAT;
188         incompat_flags = fieinfo->fi_flags & ~supported_flags;
189         if (incompat_flags) {
190                 fieinfo->fi_flags = incompat_flags;
191                 return -EBADR;
192         }
193 
194         if (fieinfo->fi_flags & FIEMAP_FLAG_SYNC)
195                 ret = filemap_write_and_wait(inode->i_mapping);
196         return ret;
197 }
198 EXPORT_SYMBOL(fiemap_prep);
199 
200 static int ioctl_fiemap(struct file *filp, struct fiemap __user *ufiemap)
201 {
202         struct fiemap fiemap;
203         struct fiemap_extent_info fieinfo = { 0, };
204         struct inode *inode = file_inode(filp);
205         int error;
206 
207         if (!inode->i_op->fiemap)
208                 return -EOPNOTSUPP;
209 
210         if (copy_from_user(&fiemap, ufiemap, sizeof(fiemap)))
211                 return -EFAULT;
212 
213         if (fiemap.fm_extent_count > FIEMAP_MAX_EXTENTS)
214                 return -EINVAL;
215 
216         fieinfo.fi_flags = fiemap.fm_flags;
217         fieinfo.fi_extents_max = fiemap.fm_extent_count;
218         fieinfo.fi_extents_start = ufiemap->fm_extents;
219 
220         error = inode->i_op->fiemap(inode, &fieinfo, fiemap.fm_start,
221                         fiemap.fm_length);
222 
223         fiemap.fm_flags = fieinfo.fi_flags;
224         fiemap.fm_mapped_extents = fieinfo.fi_extents_mapped;
225         if (copy_to_user(ufiemap, &fiemap, sizeof(fiemap)))
226                 error = -EFAULT;
227 
228         return error;
229 }
230 
231 static long ioctl_file_clone(struct file *dst_file, unsigned long srcfd,
232                              u64 off, u64 olen, u64 destoff)
233 {
234         struct fd src_file = fdget(srcfd);
235         loff_t cloned;
236         int ret;
237 
238         if (!src_file.file)
239                 return -EBADF;
240         cloned = vfs_clone_file_range(src_file.file, off, dst_file, destoff,
241                                       olen, 0);
242         if (cloned < 0)
243                 ret = cloned;
244         else if (olen && cloned != olen)
245                 ret = -EINVAL;
246         else
247                 ret = 0;
248         fdput(src_file);
249         return ret;
250 }
251 
252 static long ioctl_file_clone_range(struct file *file,
253                                    struct file_clone_range __user *argp)
254 {
255         struct file_clone_range args;
256 
257         if (copy_from_user(&args, argp, sizeof(args)))
258                 return -EFAULT;
259         return ioctl_file_clone(file, args.src_fd, args.src_offset,
260                                 args.src_length, args.dest_offset);
261 }
262 
263 /*
264  * This provides compatibility with legacy XFS pre-allocation ioctls
265  * which predate the fallocate syscall.
266  *
267  * Only the l_start, l_len and l_whence fields of the 'struct space_resv'
268  * are used here, rest are ignored.
269  */
270 static int ioctl_preallocate(struct file *filp, int mode, void __user *argp)
271 {
272         struct inode *inode = file_inode(filp);
273         struct space_resv sr;
274 
275         if (copy_from_user(&sr, argp, sizeof(sr)))
276                 return -EFAULT;
277 
278         switch (sr.l_whence) {
279         case SEEK_SET:
280                 break;
281         case SEEK_CUR:
282                 sr.l_start += filp->f_pos;
283                 break;
284         case SEEK_END:
285                 sr.l_start += i_size_read(inode);
286                 break;
287         default:
288                 return -EINVAL;
289         }
290 
291         return vfs_fallocate(filp, mode | FALLOC_FL_KEEP_SIZE, sr.l_start,
292                         sr.l_len);
293 }
294 
295 /* on ia32 l_start is on a 32-bit boundary */
296 #if defined CONFIG_COMPAT && defined(CONFIG_X86_64)
297 /* just account for different alignment */
298 static int compat_ioctl_preallocate(struct file *file, int mode,
299                                     struct space_resv_32 __user *argp)
300 {
301         struct inode *inode = file_inode(file);
302         struct space_resv_32 sr;
303 
304         if (copy_from_user(&sr, argp, sizeof(sr)))
305                 return -EFAULT;
306 
307         switch (sr.l_whence) {
308         case SEEK_SET:
309                 break;
310         case SEEK_CUR:
311                 sr.l_start += file->f_pos;
312                 break;
313         case SEEK_END:
314                 sr.l_start += i_size_read(inode);
315                 break;
316         default:
317                 return -EINVAL;
318         }
319 
320         return vfs_fallocate(file, mode | FALLOC_FL_KEEP_SIZE, sr.l_start, sr.l_len);
321 }
322 #endif
323 
324 static int file_ioctl(struct file *filp, unsigned int cmd, int __user *p)
325 {
326         switch (cmd) {
327         case FIBMAP:
328                 return ioctl_fibmap(filp, p);
329         case FS_IOC_RESVSP:
330         case FS_IOC_RESVSP64:
331                 return ioctl_preallocate(filp, 0, p);
332         case FS_IOC_UNRESVSP:
333         case FS_IOC_UNRESVSP64:
334                 return ioctl_preallocate(filp, FALLOC_FL_PUNCH_HOLE, p);
335         case FS_IOC_ZERO_RANGE:
336                 return ioctl_preallocate(filp, FALLOC_FL_ZERO_RANGE, p);
337         }
338 
339         return -ENOIOCTLCMD;
340 }
341 
342 static int ioctl_fionbio(struct file *filp, int __user *argp)
343 {
344         unsigned int flag;
345         int on, error;
346 
347         error = get_user(on, argp);
348         if (error)
349                 return error;
350         flag = O_NONBLOCK;
351 #ifdef __sparc__
352         /* SunOS compatibility item. */
353         if (O_NONBLOCK != O_NDELAY)
354                 flag |= O_NDELAY;
355 #endif
356         spin_lock(&filp->f_lock);
357         if (on)
358                 filp->f_flags |= flag;
359         else
360                 filp->f_flags &= ~flag;
361         spin_unlock(&filp->f_lock);
362         return error;
363 }
364 
365 static int ioctl_fioasync(unsigned int fd, struct file *filp,
366                           int __user *argp)
367 {
368         unsigned int flag;
369         int on, error;
370 
371         error = get_user(on, argp);
372         if (error)
373                 return error;
374         flag = on ? FASYNC : 0;
375 
376         /* Did FASYNC state change ? */
377         if ((flag ^ filp->f_flags) & FASYNC) {
378                 if (filp->f_op->fasync)
379                         /* fasync() adjusts filp->f_flags */
380                         error = filp->f_op->fasync(fd, filp, on);
381                 else
382                         error = -ENOTTY;
383         }
384         return error < 0 ? error : 0;
385 }
386 
387 static int ioctl_fsfreeze(struct file *filp)
388 {
389         struct super_block *sb = file_inode(filp)->i_sb;
390 
391         if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN))
392                 return -EPERM;
393 
394         /* If filesystem doesn't support freeze feature, return. */
395         if (sb->s_op->freeze_fs == NULL && sb->s_op->freeze_super == NULL)
396                 return -EOPNOTSUPP;
397 
398         /* Freeze */
399         if (sb->s_op->freeze_super)
400                 return sb->s_op->freeze_super(sb, FREEZE_HOLDER_USERSPACE);
401         return freeze_super(sb, FREEZE_HOLDER_USERSPACE);
402 }
403 
404 static int ioctl_fsthaw(struct file *filp)
405 {
406         struct super_block *sb = file_inode(filp)->i_sb;
407 
408         if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN))
409                 return -EPERM;
410 
411         /* Thaw */
412         if (sb->s_op->thaw_super)
413                 return sb->s_op->thaw_super(sb, FREEZE_HOLDER_USERSPACE);
414         return thaw_super(sb, FREEZE_HOLDER_USERSPACE);
415 }
416 
417 static int ioctl_file_dedupe_range(struct file *file,
418                                    struct file_dedupe_range __user *argp)
419 {
420         struct file_dedupe_range *same = NULL;
421         int ret;
422         unsigned long size;
423         u16 count;
424 
425         if (get_user(count, &argp->dest_count)) {
426                 ret = -EFAULT;
427                 goto out;
428         }
429 
430         size = offsetof(struct file_dedupe_range, info[count]);
431         if (size > PAGE_SIZE) {
432                 ret = -ENOMEM;
433                 goto out;
434         }
435 
436         same = memdup_user(argp, size);
437         if (IS_ERR(same)) {
438                 ret = PTR_ERR(same);
439                 same = NULL;
440                 goto out;
441         }
442 
443         same->dest_count = count;
444         ret = vfs_dedupe_file_range(file, same);
445         if (ret)
446                 goto out;
447 
448         ret = copy_to_user(argp, same, size);
449         if (ret)
450                 ret = -EFAULT;
451 
452 out:
453         kfree(same);
454         return ret;
455 }
456 
457 /**
458  * fileattr_fill_xflags - initialize fileattr with xflags
459  * @fa:         fileattr pointer
460  * @xflags:     FS_XFLAG_* flags
461  *
462  * Set ->fsx_xflags, ->fsx_valid and ->flags (translated xflags).  All
463  * other fields are zeroed.
464  */
465 void fileattr_fill_xflags(struct fileattr *fa, u32 xflags)
466 {
467         memset(fa, 0, sizeof(*fa));
468         fa->fsx_valid = true;
469         fa->fsx_xflags = xflags;
470         if (fa->fsx_xflags & FS_XFLAG_IMMUTABLE)
471                 fa->flags |= FS_IMMUTABLE_FL;
472         if (fa->fsx_xflags & FS_XFLAG_APPEND)
473                 fa->flags |= FS_APPEND_FL;
474         if (fa->fsx_xflags & FS_XFLAG_SYNC)
475                 fa->flags |= FS_SYNC_FL;
476         if (fa->fsx_xflags & FS_XFLAG_NOATIME)
477                 fa->flags |= FS_NOATIME_FL;
478         if (fa->fsx_xflags & FS_XFLAG_NODUMP)
479                 fa->flags |= FS_NODUMP_FL;
480         if (fa->fsx_xflags & FS_XFLAG_DAX)
481                 fa->flags |= FS_DAX_FL;
482         if (fa->fsx_xflags & FS_XFLAG_PROJINHERIT)
483                 fa->flags |= FS_PROJINHERIT_FL;
484 }
485 EXPORT_SYMBOL(fileattr_fill_xflags);
486 
487 /**
488  * fileattr_fill_flags - initialize fileattr with flags
489  * @fa:         fileattr pointer
490  * @flags:      FS_*_FL flags
491  *
492  * Set ->flags, ->flags_valid and ->fsx_xflags (translated flags).
493  * All other fields are zeroed.
494  */
495 void fileattr_fill_flags(struct fileattr *fa, u32 flags)
496 {
497         memset(fa, 0, sizeof(*fa));
498         fa->flags_valid = true;
499         fa->flags = flags;
500         if (fa->flags & FS_SYNC_FL)
501                 fa->fsx_xflags |= FS_XFLAG_SYNC;
502         if (fa->flags & FS_IMMUTABLE_FL)
503                 fa->fsx_xflags |= FS_XFLAG_IMMUTABLE;
504         if (fa->flags & FS_APPEND_FL)
505                 fa->fsx_xflags |= FS_XFLAG_APPEND;
506         if (fa->flags & FS_NODUMP_FL)
507                 fa->fsx_xflags |= FS_XFLAG_NODUMP;
508         if (fa->flags & FS_NOATIME_FL)
509                 fa->fsx_xflags |= FS_XFLAG_NOATIME;
510         if (fa->flags & FS_DAX_FL)
511                 fa->fsx_xflags |= FS_XFLAG_DAX;
512         if (fa->flags & FS_PROJINHERIT_FL)
513                 fa->fsx_xflags |= FS_XFLAG_PROJINHERIT;
514 }
515 EXPORT_SYMBOL(fileattr_fill_flags);
516 
517 /**
518  * vfs_fileattr_get - retrieve miscellaneous file attributes
519  * @dentry:     the object to retrieve from
520  * @fa:         fileattr pointer
521  *
522  * Call i_op->fileattr_get() callback, if exists.
523  *
524  * Return: 0 on success, or a negative error on failure.
525  */
526 int vfs_fileattr_get(struct dentry *dentry, struct fileattr *fa)
527 {
528         struct inode *inode = d_inode(dentry);
529 
530         if (!inode->i_op->fileattr_get)
531                 return -ENOIOCTLCMD;
532 
533         return inode->i_op->fileattr_get(dentry, fa);
534 }
535 EXPORT_SYMBOL(vfs_fileattr_get);
536 
537 /**
538  * copy_fsxattr_to_user - copy fsxattr to userspace.
539  * @fa:         fileattr pointer
540  * @ufa:        fsxattr user pointer
541  *
542  * Return: 0 on success, or -EFAULT on failure.
543  */
544 int copy_fsxattr_to_user(const struct fileattr *fa, struct fsxattr __user *ufa)
545 {
546         struct fsxattr xfa;
547 
548         memset(&xfa, 0, sizeof(xfa));
549         xfa.fsx_xflags = fa->fsx_xflags;
550         xfa.fsx_extsize = fa->fsx_extsize;
551         xfa.fsx_nextents = fa->fsx_nextents;
552         xfa.fsx_projid = fa->fsx_projid;
553         xfa.fsx_cowextsize = fa->fsx_cowextsize;
554 
555         if (copy_to_user(ufa, &xfa, sizeof(xfa)))
556                 return -EFAULT;
557 
558         return 0;
559 }
560 EXPORT_SYMBOL(copy_fsxattr_to_user);
561 
562 static int copy_fsxattr_from_user(struct fileattr *fa,
563                                   struct fsxattr __user *ufa)
564 {
565         struct fsxattr xfa;
566 
567         if (copy_from_user(&xfa, ufa, sizeof(xfa)))
568                 return -EFAULT;
569 
570         fileattr_fill_xflags(fa, xfa.fsx_xflags);
571         fa->fsx_extsize = xfa.fsx_extsize;
572         fa->fsx_nextents = xfa.fsx_nextents;
573         fa->fsx_projid = xfa.fsx_projid;
574         fa->fsx_cowextsize = xfa.fsx_cowextsize;
575 
576         return 0;
577 }
578 
579 /*
580  * Generic function to check FS_IOC_FSSETXATTR/FS_IOC_SETFLAGS values and reject
581  * any invalid configurations.
582  *
583  * Note: must be called with inode lock held.
584  */
585 static int fileattr_set_prepare(struct inode *inode,
586                               const struct fileattr *old_ma,
587                               struct fileattr *fa)
588 {
589         int err;
590 
591         /*
592          * The IMMUTABLE and APPEND_ONLY flags can only be changed by
593          * the relevant capability.
594          */
595         if ((fa->flags ^ old_ma->flags) & (FS_APPEND_FL | FS_IMMUTABLE_FL) &&
596             !capable(CAP_LINUX_IMMUTABLE))
597                 return -EPERM;
598 
599         err = fscrypt_prepare_setflags(inode, old_ma->flags, fa->flags);
600         if (err)
601                 return err;
602 
603         /*
604          * Project Quota ID state is only allowed to change from within the init
605          * namespace. Enforce that restriction only if we are trying to change
606          * the quota ID state. Everything else is allowed in user namespaces.
607          */
608         if (current_user_ns() != &init_user_ns) {
609                 if (old_ma->fsx_projid != fa->fsx_projid)
610                         return -EINVAL;
611                 if ((old_ma->fsx_xflags ^ fa->fsx_xflags) &
612                                 FS_XFLAG_PROJINHERIT)
613                         return -EINVAL;
614         } else {
615                 /*
616                  * Caller is allowed to change the project ID. If it is being
617                  * changed, make sure that the new value is valid.
618                  */
619                 if (old_ma->fsx_projid != fa->fsx_projid &&
620                     !projid_valid(make_kprojid(&init_user_ns, fa->fsx_projid)))
621                         return -EINVAL;
622         }
623 
624         /* Check extent size hints. */
625         if ((fa->fsx_xflags & FS_XFLAG_EXTSIZE) && !S_ISREG(inode->i_mode))
626                 return -EINVAL;
627 
628         if ((fa->fsx_xflags & FS_XFLAG_EXTSZINHERIT) &&
629                         !S_ISDIR(inode->i_mode))
630                 return -EINVAL;
631 
632         if ((fa->fsx_xflags & FS_XFLAG_COWEXTSIZE) &&
633             !S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
634                 return -EINVAL;
635 
636         /*
637          * It is only valid to set the DAX flag on regular files and
638          * directories on filesystems.
639          */
640         if ((fa->fsx_xflags & FS_XFLAG_DAX) &&
641             !(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)))
642                 return -EINVAL;
643 
644         /* Extent size hints of zero turn off the flags. */
645         if (fa->fsx_extsize == 0)
646                 fa->fsx_xflags &= ~(FS_XFLAG_EXTSIZE | FS_XFLAG_EXTSZINHERIT);
647         if (fa->fsx_cowextsize == 0)
648                 fa->fsx_xflags &= ~FS_XFLAG_COWEXTSIZE;
649 
650         return 0;
651 }
652 
653 /**
654  * vfs_fileattr_set - change miscellaneous file attributes
655  * @idmap:      idmap of the mount
656  * @dentry:     the object to change
657  * @fa:         fileattr pointer
658  *
659  * After verifying permissions, call i_op->fileattr_set() callback, if
660  * exists.
661  *
662  * Verifying attributes involves retrieving current attributes with
663  * i_op->fileattr_get(), this also allows initializing attributes that have
664  * not been set by the caller to current values.  Inode lock is held
665  * thoughout to prevent racing with another instance.
666  *
667  * Return: 0 on success, or a negative error on failure.
668  */
669 int vfs_fileattr_set(struct mnt_idmap *idmap, struct dentry *dentry,
670                      struct fileattr *fa)
671 {
672         struct inode *inode = d_inode(dentry);
673         struct fileattr old_ma = {};
674         int err;
675 
676         if (!inode->i_op->fileattr_set)
677                 return -ENOIOCTLCMD;
678 
679         if (!inode_owner_or_capable(idmap, inode))
680                 return -EPERM;
681 
682         inode_lock(inode);
683         err = vfs_fileattr_get(dentry, &old_ma);
684         if (!err) {
685                 /* initialize missing bits from old_ma */
686                 if (fa->flags_valid) {
687                         fa->fsx_xflags |= old_ma.fsx_xflags & ~FS_XFLAG_COMMON;
688                         fa->fsx_extsize = old_ma.fsx_extsize;
689                         fa->fsx_nextents = old_ma.fsx_nextents;
690                         fa->fsx_projid = old_ma.fsx_projid;
691                         fa->fsx_cowextsize = old_ma.fsx_cowextsize;
692                 } else {
693                         fa->flags |= old_ma.flags & ~FS_COMMON_FL;
694                 }
695                 err = fileattr_set_prepare(inode, &old_ma, fa);
696                 if (!err)
697                         err = inode->i_op->fileattr_set(idmap, dentry, fa);
698         }
699         inode_unlock(inode);
700 
701         return err;
702 }
703 EXPORT_SYMBOL(vfs_fileattr_set);
704 
705 static int ioctl_getflags(struct file *file, unsigned int __user *argp)
706 {
707         struct fileattr fa = { .flags_valid = true }; /* hint only */
708         int err;
709 
710         err = vfs_fileattr_get(file->f_path.dentry, &fa);
711         if (!err)
712                 err = put_user(fa.flags, argp);
713         return err;
714 }
715 
716 static int ioctl_setflags(struct file *file, unsigned int __user *argp)
717 {
718         struct mnt_idmap *idmap = file_mnt_idmap(file);
719         struct dentry *dentry = file->f_path.dentry;
720         struct fileattr fa;
721         unsigned int flags;
722         int err;
723 
724         err = get_user(flags, argp);
725         if (!err) {
726                 err = mnt_want_write_file(file);
727                 if (!err) {
728                         fileattr_fill_flags(&fa, flags);
729                         err = vfs_fileattr_set(idmap, dentry, &fa);
730                         mnt_drop_write_file(file);
731                 }
732         }
733         return err;
734 }
735 
736 static int ioctl_fsgetxattr(struct file *file, void __user *argp)
737 {
738         struct fileattr fa = { .fsx_valid = true }; /* hint only */
739         int err;
740 
741         err = vfs_fileattr_get(file->f_path.dentry, &fa);
742         if (!err)
743                 err = copy_fsxattr_to_user(&fa, argp);
744 
745         return err;
746 }
747 
748 static int ioctl_fssetxattr(struct file *file, void __user *argp)
749 {
750         struct mnt_idmap *idmap = file_mnt_idmap(file);
751         struct dentry *dentry = file->f_path.dentry;
752         struct fileattr fa;
753         int err;
754 
755         err = copy_fsxattr_from_user(&fa, argp);
756         if (!err) {
757                 err = mnt_want_write_file(file);
758                 if (!err) {
759                         err = vfs_fileattr_set(idmap, dentry, &fa);
760                         mnt_drop_write_file(file);
761                 }
762         }
763         return err;
764 }
765 
766 static int ioctl_getfsuuid(struct file *file, void __user *argp)
767 {
768         struct super_block *sb = file_inode(file)->i_sb;
769         struct fsuuid2 u = { .len = sb->s_uuid_len, };
770 
771         if (!sb->s_uuid_len)
772                 return -ENOTTY;
773 
774         memcpy(&u.uuid[0], &sb->s_uuid, sb->s_uuid_len);
775 
776         return copy_to_user(argp, &u, sizeof(u)) ? -EFAULT : 0;
777 }
778 
779 static int ioctl_get_fs_sysfs_path(struct file *file, void __user *argp)
780 {
781         struct super_block *sb = file_inode(file)->i_sb;
782 
783         if (!strlen(sb->s_sysfs_name))
784                 return -ENOTTY;
785 
786         struct fs_sysfs_path u = {};
787 
788         u.len = scnprintf(u.name, sizeof(u.name), "%s/%s", sb->s_type->name, sb->s_sysfs_name);
789 
790         return copy_to_user(argp, &u, sizeof(u)) ? -EFAULT : 0;
791 }
792 
793 /*
794  * do_vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d.
795  * It's just a simple helper for sys_ioctl and compat_sys_ioctl.
796  *
797  * When you add any new common ioctls to the switches above and below,
798  * please ensure they have compatible arguments in compat mode.
799  *
800  * The LSM mailing list should also be notified of any command additions or
801  * changes, as specific LSMs may be affected.
802  */
803 static int do_vfs_ioctl(struct file *filp, unsigned int fd,
804                         unsigned int cmd, unsigned long arg)
805 {
806         void __user *argp = (void __user *)arg;
807         struct inode *inode = file_inode(filp);
808 
809         switch (cmd) {
810         case FIOCLEX:
811                 set_close_on_exec(fd, 1);
812                 return 0;
813 
814         case FIONCLEX:
815                 set_close_on_exec(fd, 0);
816                 return 0;
817 
818         case FIONBIO:
819                 return ioctl_fionbio(filp, argp);
820 
821         case FIOASYNC:
822                 return ioctl_fioasync(fd, filp, argp);
823 
824         case FIOQSIZE:
825                 if (S_ISDIR(inode->i_mode) || S_ISREG(inode->i_mode) ||
826                     S_ISLNK(inode->i_mode)) {
827                         loff_t res = inode_get_bytes(inode);
828                         return copy_to_user(argp, &res, sizeof(res)) ?
829                                             -EFAULT : 0;
830                 }
831 
832                 return -ENOTTY;
833 
834         case FIFREEZE:
835                 return ioctl_fsfreeze(filp);
836 
837         case FITHAW:
838                 return ioctl_fsthaw(filp);
839 
840         case FS_IOC_FIEMAP:
841                 return ioctl_fiemap(filp, argp);
842 
843         case FIGETBSZ:
844                 /* anon_bdev filesystems may not have a block size */
845                 if (!inode->i_sb->s_blocksize)
846                         return -EINVAL;
847 
848                 return put_user(inode->i_sb->s_blocksize, (int __user *)argp);
849 
850         case FICLONE:
851                 return ioctl_file_clone(filp, arg, 0, 0, 0);
852 
853         case FICLONERANGE:
854                 return ioctl_file_clone_range(filp, argp);
855 
856         case FIDEDUPERANGE:
857                 return ioctl_file_dedupe_range(filp, argp);
858 
859         case FIONREAD:
860                 if (!S_ISREG(inode->i_mode))
861                         return vfs_ioctl(filp, cmd, arg);
862 
863                 return put_user(i_size_read(inode) - filp->f_pos,
864                                 (int __user *)argp);
865 
866         case FS_IOC_GETFLAGS:
867                 return ioctl_getflags(filp, argp);
868 
869         case FS_IOC_SETFLAGS:
870                 return ioctl_setflags(filp, argp);
871 
872         case FS_IOC_FSGETXATTR:
873                 return ioctl_fsgetxattr(filp, argp);
874 
875         case FS_IOC_FSSETXATTR:
876                 return ioctl_fssetxattr(filp, argp);
877 
878         case FS_IOC_GETFSUUID:
879                 return ioctl_getfsuuid(filp, argp);
880 
881         case FS_IOC_GETFSSYSFSPATH:
882                 return ioctl_get_fs_sysfs_path(filp, argp);
883 
884         default:
885                 if (S_ISREG(inode->i_mode))
886                         return file_ioctl(filp, cmd, argp);
887                 break;
888         }
889 
890         return -ENOIOCTLCMD;
891 }
892 
893 SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
894 {
895         struct fd f = fdget(fd);
896         int error;
897 
898         if (!f.file)
899                 return -EBADF;
900 
901         error = security_file_ioctl(f.file, cmd, arg);
902         if (error)
903                 goto out;
904 
905         error = do_vfs_ioctl(f.file, fd, cmd, arg);
906         if (error == -ENOIOCTLCMD)
907                 error = vfs_ioctl(f.file, cmd, arg);
908 
909 out:
910         fdput(f);
911         return error;
912 }
913 
914 #ifdef CONFIG_COMPAT
915 /**
916  * compat_ptr_ioctl - generic implementation of .compat_ioctl file operation
917  * @file: The file to operate on.
918  * @cmd: The ioctl command number.
919  * @arg: The argument to the ioctl.
920  *
921  * This is not normally called as a function, but instead set in struct
922  * file_operations as
923  *
924  *     .compat_ioctl = compat_ptr_ioctl,
925  *
926  * On most architectures, the compat_ptr_ioctl() just passes all arguments
927  * to the corresponding ->ioctl handler. The exception is arch/s390, where
928  * compat_ptr() clears the top bit of a 32-bit pointer value, so user space
929  * pointers to the second 2GB alias the first 2GB, as is the case for
930  * native 32-bit s390 user space.
931  *
932  * The compat_ptr_ioctl() function must therefore be used only with ioctl
933  * functions that either ignore the argument or pass a pointer to a
934  * compatible data type.
935  *
936  * If any ioctl command handled by fops->unlocked_ioctl passes a plain
937  * integer instead of a pointer, or any of the passed data types
938  * is incompatible between 32-bit and 64-bit architectures, a proper
939  * handler is required instead of compat_ptr_ioctl.
940  */
941 long compat_ptr_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
942 {
943         if (!file->f_op->unlocked_ioctl)
944                 return -ENOIOCTLCMD;
945 
946         return file->f_op->unlocked_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
947 }
948 EXPORT_SYMBOL(compat_ptr_ioctl);
949 
950 COMPAT_SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd,
951                        compat_ulong_t, arg)
952 {
953         struct fd f = fdget(fd);
954         int error;
955 
956         if (!f.file)
957                 return -EBADF;
958 
959         error = security_file_ioctl_compat(f.file, cmd, arg);
960         if (error)
961                 goto out;
962 
963         switch (cmd) {
964         /* FICLONE takes an int argument, so don't use compat_ptr() */
965         case FICLONE:
966                 error = ioctl_file_clone(f.file, arg, 0, 0, 0);
967                 break;
968 
969 #if defined(CONFIG_X86_64)
970         /* these get messy on amd64 due to alignment differences */
971         case FS_IOC_RESVSP_32:
972         case FS_IOC_RESVSP64_32:
973                 error = compat_ioctl_preallocate(f.file, 0, compat_ptr(arg));
974                 break;
975         case FS_IOC_UNRESVSP_32:
976         case FS_IOC_UNRESVSP64_32:
977                 error = compat_ioctl_preallocate(f.file, FALLOC_FL_PUNCH_HOLE,
978                                 compat_ptr(arg));
979                 break;
980         case FS_IOC_ZERO_RANGE_32:
981                 error = compat_ioctl_preallocate(f.file, FALLOC_FL_ZERO_RANGE,
982                                 compat_ptr(arg));
983                 break;
984 #endif
985 
986         /*
987          * These access 32-bit values anyway so no further handling is
988          * necessary.
989          */
990         case FS_IOC32_GETFLAGS:
991         case FS_IOC32_SETFLAGS:
992                 cmd = (cmd == FS_IOC32_GETFLAGS) ?
993                         FS_IOC_GETFLAGS : FS_IOC_SETFLAGS;
994                 fallthrough;
995         /*
996          * everything else in do_vfs_ioctl() takes either a compatible
997          * pointer argument or no argument -- call it with a modified
998          * argument.
999          */
1000         default:
1001                 error = do_vfs_ioctl(f.file, fd, cmd,
1002                                      (unsigned long)compat_ptr(arg));
1003                 if (error != -ENOIOCTLCMD)
1004                         break;
1005 
1006                 if (f.file->f_op->compat_ioctl)
1007                         error = f.file->f_op->compat_ioctl(f.file, cmd, arg);
1008                 if (error == -ENOIOCTLCMD)
1009                         error = -ENOTTY;
1010                 break;
1011         }
1012 
1013  out:
1014         fdput(f);
1015 
1016         return error;
1017 }
1018 #endif
1019 

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