fs/ubifs/ioctl.c

   1 /*
   2  * This file is part of UBIFS.
   3  *
   4  * Copyright (C) 2006-2008 Nokia Corporation.
   5  * Copyright (C) 2006, 2007 University of Szeged, Hungary
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License version 2 as published by
   9  * the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14  * more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along with
  17  * this program; if not, write to the Free Software Foundation, Inc., 51
  18  * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  19  *
  20  * Authors: Zoltan Sogor
  21  *          Artem Bityutskiy (Битюцкий Артём)
  22  *          Adrian Hunter
  23  */
  24
  25 /* This file implements EXT2-compatible extended attribute ioctl() calls */
  26
  27 #include <linux/compat.h>
  28 #include <linux/mount.h>
  29 #include "ubifs.h"
  30
  31 /* Need to be kept consistent with checked flags in ioctl2ubifs() */
  32 #define UBIFS_SUPPORTED_IOCTL_FLAGS \
  33         (FS_COMPR_FL | FS_SYNC_FL | FS_APPEND_FL | \
  34          FS_IMMUTABLE_FL | FS_DIRSYNC_FL)
  35
  36 /**
  37  * ubifs_set_inode_flags - set VFS inode flags.
  38  * @inode: VFS inode to set flags for
  39  *
  40  * This function propagates flags from UBIFS inode object to VFS inode object.
  41  */
  42 void ubifs_set_inode_flags(struct inode *inode)
  43 {
  44         unsigned int flags = ubifs_inode(inode)->flags;
  45
  46         inode->i_flags &= ~(S_SYNC | S_APPEND | S_IMMUTABLE | S_DIRSYNC);
  47         if (flags & UBIFS_SYNC_FL)
  48                 inode->i_flags |= S_SYNC;
  49         if (flags & UBIFS_APPEND_FL)
  50                 inode->i_flags |= S_APPEND;
  51         if (flags & UBIFS_IMMUTABLE_FL)
  52                 inode->i_flags |= S_IMMUTABLE;
  53         if (flags & UBIFS_DIRSYNC_FL)
  54                 inode->i_flags |= S_DIRSYNC;
  55 }
  56
  57 /*
  58  * ioctl2ubifs - convert ioctl inode flags to UBIFS inode flags.
  59  * @ioctl_flags: flags to convert
  60  *
  61  * This function converts ioctl flags (@FS_COMPR_FL, etc) to UBIFS inode flags
  62  * (@UBIFS_COMPR_FL, etc).
  63  */
  64 static int ioctl2ubifs(int ioctl_flags)
  65 {
  66         int ubifs_flags = 0;
  67
  68         if (ioctl_flags & FS_COMPR_FL)
  69                 ubifs_flags |= UBIFS_COMPR_FL;
  70         if (ioctl_flags & FS_SYNC_FL)
  71                 ubifs_flags |= UBIFS_SYNC_FL;
  72         if (ioctl_flags & FS_APPEND_FL)
  73                 ubifs_flags |= UBIFS_APPEND_FL;
  74         if (ioctl_flags & FS_IMMUTABLE_FL)
  75                 ubifs_flags |= UBIFS_IMMUTABLE_FL;
  76         if (ioctl_flags & FS_DIRSYNC_FL)
  77                 ubifs_flags |= UBIFS_DIRSYNC_FL;
  78
  79         return ubifs_flags;
  80 }
  81
  82 /*
  83  * ubifs2ioctl - convert UBIFS inode flags to ioctl inode flags.
  84  * @ubifs_flags: flags to convert
  85  *
  86  * This function converts UBIFS inode flags (@UBIFS_COMPR_FL, etc) to ioctl
  87  * flags (@FS_COMPR_FL, etc).
  88  */
  89 static int ubifs2ioctl(int ubifs_flags)
  90 {
  91         int ioctl_flags = 0;
  92
  93         if (ubifs_flags & UBIFS_COMPR_FL)
  94                 ioctl_flags |= FS_COMPR_FL;
  95         if (ubifs_flags & UBIFS_SYNC_FL)
  96                 ioctl_flags |= FS_SYNC_FL;
  97         if (ubifs_flags & UBIFS_APPEND_FL)
  98                 ioctl_flags |= FS_APPEND_FL;
  99         if (ubifs_flags & UBIFS_IMMUTABLE_FL)
 100                 ioctl_flags |= FS_IMMUTABLE_FL;
 101         if (ubifs_flags & UBIFS_DIRSYNC_FL)
 102                 ioctl_flags |= FS_DIRSYNC_FL;
 103
 104         return ioctl_flags;
 105 }
 106
 107 static int setflags(struct inode *inode, int flags)
 108 {
 109         int oldflags, err, release;
 110         struct ubifs_inode *ui = ubifs_inode(inode);
 111         struct ubifs_info *c = inode->i_sb->s_fs_info;
 112         struct ubifs_budget_req req = { .dirtied_ino = 1,
 113                                         .dirtied_ino_d = ui->data_len };
 114
 115         err = ubifs_budget_space(c, &req);
 116         if (err)
 117                 return err;
 118
 119         /*
 120          * The IMMUTABLE and APPEND_ONLY flags can only be changed by
 121          * the relevant capability.
 122          */
 123         mutex_lock(&ui->ui_mutex);
 124         oldflags = ubifs2ioctl(ui->flags);
 125         if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) {
 126                 if (!capable(CAP_LINUX_IMMUTABLE)) {
 127                         err = -EPERM;
 128                         goto out_unlock;
 129                 }
 130         }
 131
 132         ui->flags &= ~ioctl2ubifs(UBIFS_SUPPORTED_IOCTL_FLAGS);
 133         ui->flags |= ioctl2ubifs(flags);
 134         ubifs_set_inode_flags(inode);
 135         inode->i_ctime = current_time(inode);
 136         release = ui->dirty;
 137         mark_inode_dirty_sync(inode);
 138         mutex_unlock(&ui->ui_mutex);
 139
 140         if (release)
 141                 ubifs_release_budget(c, &req);
 142         if (IS_SYNC(inode))
 143                 err = write_inode_now(inode, 1);
 144         return err;
 145
 146 out_unlock:
 147         ubifs_err(c, "can't modify inode %lu attributes", inode->i_ino);
 148         mutex_unlock(&ui->ui_mutex);
 149         ubifs_release_budget(c, &req);
 150         return err;
 151 }
 152
 153 long ubifs_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 154 {
 155         int flags, err;
 156         struct inode *inode = file_inode(file);
 157
 158         switch (cmd) {
 159         case FS_IOC_GETFLAGS:
 160                 flags = ubifs2ioctl(ubifs_inode(inode)->flags);
 161
 162                 dbg_gen("get flags: %#x, i_flags %#x", flags, inode->i_flags);
 163                 return put_user(flags, (int __user *) arg);
 164
 165         case FS_IOC_SETFLAGS: {
 166                 if (IS_RDONLY(inode))
 167                         return -EROFS;
 168
 169                 if (!inode_owner_or_capable(inode))
 170                         return -EACCES;
 171
 172                 if (get_user(flags, (int __user *) arg))
 173                         return -EFAULT;
 174
 175                 if (flags & ~UBIFS_SUPPORTED_IOCTL_FLAGS)
 176                         return -EOPNOTSUPP;
 177
 178                 if (!S_ISDIR(inode->i_mode))
 179                         flags &= ~FS_DIRSYNC_FL;
 180
 181                 /*
 182                  * Make sure the file-system is read-write and make sure it
 183                  * will not become read-only while we are changing the flags.
 184                  */
 185                 err = mnt_want_write_file(file);
 186                 if (err)
 187                         return err;
 188                 dbg_gen("set flags: %#x, i_flags %#x", flags, inode->i_flags);
 189                 err = setflags(inode, flags);
 190                 mnt_drop_write_file(file);
 191                 return err;
 192         }
 193         case FS_IOC_SET_ENCRYPTION_POLICY: {
 194 #ifdef CONFIG_UBIFS_FS_ENCRYPTION
 195                 struct ubifs_info *c = inode->i_sb->s_fs_info;
 196
 197                 err = ubifs_enable_encryption(c);
 198                 if (err)
 199                         return err;
 200
 201                 return fscrypt_ioctl_set_policy(file, (const void __user *)arg);
 202 #else
 203                 return -EOPNOTSUPP;
 204 #endif
 205         }
 206         case FS_IOC_GET_ENCRYPTION_POLICY: {
 207 #ifdef CONFIG_UBIFS_FS_ENCRYPTION
 208                 return fscrypt_ioctl_get_policy(file, (void __user *)arg);
 209 #else
 210                 return -EOPNOTSUPP;
 211 #endif
 212         }
 213
 214         default:
 215                 return -ENOTTY;
 216         }
 217 }
 218
 219 #ifdef CONFIG_COMPAT
 220 long ubifs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 221 {
 222         switch (cmd) {
 223         case FS_IOC32_GETFLAGS:
 224                 cmd = FS_IOC_GETFLAGS;
 225                 break;
 226         case FS_IOC32_SETFLAGS:
 227                 cmd = FS_IOC_SETFLAGS;
 228                 break;
 229         case FS_IOC_SET_ENCRYPTION_POLICY:
 230         case FS_IOC_GET_ENCRYPTION_POLICY:
 231                 break;
 232         default:
 233                 return -ENOIOCTLCMD;
 234         }
 235         return ubifs_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
 236 }
 237 #endif