fs/ext2/ioctl.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * linux/fs/ext2/ioctl.c
   4  *
   5  * Copyright (C) 1993, 1994, 1995
   6  * Remy Card (card@masi.ibp.fr)
   7  * Laboratoire MASI - Institut Blaise Pascal
   8  * Universite Pierre et Marie Curie (Paris VI)
   9  */
  10
  11 #include "ext2.h"
  12 #include <linux/capability.h>
  13 #include <linux/time.h>
  14 #include <linux/sched.h>
  15 #include <linux/compat.h>
  16 #include <linux/mount.h>
  17 #include <asm/current.h>
  18 #include <linux/uaccess.h>
  19
  20
  21 long ext2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
  22 {
  23         struct inode *inode = file_inode(filp);
  24         struct ext2_inode_info *ei = EXT2_I(inode);
  25         unsigned int flags;
  26         unsigned short rsv_window_size;
  27         int ret;
  28
  29         ext2_debug ("cmd = %u, arg = %lu\n", cmd, arg);
  30
  31         switch (cmd) {
  32         case EXT2_IOC_GETFLAGS:
  33                 flags = ei->i_flags & EXT2_FL_USER_VISIBLE;
  34                 return put_user(flags, (int __user *) arg);
  35         case EXT2_IOC_SETFLAGS: {
  36                 unsigned int oldflags;
  37
  38                 ret = mnt_want_write_file(filp);
  39                 if (ret)
  40                         return ret;
  41
  42                 if (!inode_owner_or_capable(inode)) {
  43                         ret = -EACCES;
  44                         goto setflags_out;
  45                 }
  46
  47                 if (get_user(flags, (int __user *) arg)) {
  48                         ret = -EFAULT;
  49                         goto setflags_out;
  50                 }
  51
  52                 flags = ext2_mask_flags(inode->i_mode, flags);
  53
  54                 inode_lock(inode);
  55                 /* Is it quota file? Do not allow user to mess with it */
  56                 if (IS_NOQUOTA(inode)) {
  57                         inode_unlock(inode);
  58                         ret = -EPERM;
  59                         goto setflags_out;
  60                 }
  61                 oldflags = ei->i_flags;
  62
  63                 /*
  64                  * The IMMUTABLE and APPEND_ONLY flags can only be changed by
  65                  * the relevant capability.
  66                  *
  67                  * This test looks nicer. Thanks to Pauline Middelink
  68                  */
  69                 if ((flags ^ oldflags) & (EXT2_APPEND_FL | EXT2_IMMUTABLE_FL)) {
  70                         if (!capable(CAP_LINUX_IMMUTABLE)) {
  71                                 inode_unlock(inode);
  72                                 ret = -EPERM;
  73                                 goto setflags_out;
  74                         }
  75                 }
  76
  77                 flags = flags & EXT2_FL_USER_MODIFIABLE;
  78                 flags |= oldflags & ~EXT2_FL_USER_MODIFIABLE;
  79                 ei->i_flags = flags;
  80
  81                 ext2_set_inode_flags(inode);
  82                 inode->i_ctime = current_time(inode);
  83                 inode_unlock(inode);
  84
  85                 mark_inode_dirty(inode);
  86 setflags_out:
  87                 mnt_drop_write_file(filp);
  88                 return ret;
  89         }
  90         case EXT2_IOC_GETVERSION:
  91                 return put_user(inode->i_generation, (int __user *) arg);
  92         case EXT2_IOC_SETVERSION: {
  93                 __u32 generation;
  94
  95                 if (!inode_owner_or_capable(inode))
  96                         return -EPERM;
  97                 ret = mnt_want_write_file(filp);
  98                 if (ret)
  99                         return ret;
 100                 if (get_user(generation, (int __user *) arg)) {
 101                         ret = -EFAULT;
 102                         goto setversion_out;
 103                 }
 104
 105                 inode_lock(inode);
 106                 inode->i_ctime = current_time(inode);
 107                 inode->i_generation = generation;
 108                 inode_unlock(inode);
 109
 110                 mark_inode_dirty(inode);
 111 setversion_out:
 112                 mnt_drop_write_file(filp);
 113                 return ret;
 114         }
 115         case EXT2_IOC_GETRSVSZ:
 116                 if (test_opt(inode->i_sb, RESERVATION)
 117                         && S_ISREG(inode->i_mode)
 118                         && ei->i_block_alloc_info) {
 119                         rsv_window_size = ei->i_block_alloc_info->rsv_window_node.rsv_goal_size;
 120                         return put_user(rsv_window_size, (int __user *)arg);
 121                 }
 122                 return -ENOTTY;
 123         case EXT2_IOC_SETRSVSZ: {
 124
 125                 if (!test_opt(inode->i_sb, RESERVATION) ||!S_ISREG(inode->i_mode))
 126                         return -ENOTTY;
 127
 128                 if (!inode_owner_or_capable(inode))
 129                         return -EACCES;
 130
 131                 if (get_user(rsv_window_size, (int __user *)arg))
 132                         return -EFAULT;
 133
 134                 ret = mnt_want_write_file(filp);
 135                 if (ret)
 136                         return ret;
 137
 138                 if (rsv_window_size > EXT2_MAX_RESERVE_BLOCKS)
 139                         rsv_window_size = EXT2_MAX_RESERVE_BLOCKS;
 140
 141                 /*
 142                  * need to allocate reservation structure for this inode
 143                  * before set the window size
 144                  */
 145                 /*
 146                  * XXX What lock should protect the rsv_goal_size?
 147                  * Accessed in ext2_get_block only.  ext3 uses i_truncate.
 148                  */
 149                 mutex_lock(&ei->truncate_mutex);
 150                 if (!ei->i_block_alloc_info)
 151                         ext2_init_block_alloc_info(inode);
 152
 153                 if (ei->i_block_alloc_info){
 154                         struct ext2_reserve_window_node *rsv = &ei->i_block_alloc_info->rsv_window_node;
 155                         rsv->rsv_goal_size = rsv_window_size;
 156                 }
 157                 mutex_unlock(&ei->truncate_mutex);
 158                 mnt_drop_write_file(filp);
 159                 return 0;
 160         }
 161         default:
 162                 return -ENOTTY;
 163         }
 164 }
 165
 166 #ifdef CONFIG_COMPAT
 167 long ext2_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 168 {
 169         /* These are just misnamed, they actually get/put from/to user an int */
 170         switch (cmd) {
 171         case EXT2_IOC32_GETFLAGS:
 172                 cmd = EXT2_IOC_GETFLAGS;
 173                 break;
 174         case EXT2_IOC32_SETFLAGS:
 175                 cmd = EXT2_IOC_SETFLAGS;
 176                 break;
 177         case EXT2_IOC32_GETVERSION:
 178                 cmd = EXT2_IOC_GETVERSION;
 179                 break;
 180         case EXT2_IOC32_SETVERSION:
 181                 cmd = EXT2_IOC_SETVERSION;
 182                 break;
 183         default:
 184                 return -ENOIOCTLCMD;
 185         }
 186         return ext2_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
 187 }
 188 #endif