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linux/fs/ubifs/ioctl.c
Christian Brauner 21cb47be6f
inode: make init and permission helpers idmapped mount aware 
The inode_owner_or_capable() helper determines whether the caller is the
owner of the inode or is capable with respect to that inode. Allow it to
handle idmapped mounts. If the inode is accessed through an idmapped
mount it according to the mount's user namespace. Afterwards the checks
are identical to non-idmapped mounts. If the initial user namespace is
passed nothing changes so non-idmapped mounts will see identical
behavior as before.

Similarly, allow the inode_init_owner() helper to handle idmapped
mounts. It initializes a new inode on idmapped mounts by mapping the
fsuid and fsgid of the caller from the mount's user namespace. If the
initial user namespace is passed nothing changes so non-idmapped mounts
will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-7-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24 14:27:16 +01:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* This file is part of UBIFS.
*
* Copyright (C) 2006-2008 Nokia Corporation.
* Copyright (C) 2006, 2007 University of Szeged, Hungary
*
* Authors: Zoltan Sogor
* Artem Bityutskiy (Битюцкий Артём)
* Adrian Hunter
*/
/* This file implements EXT2-compatible extended attribute ioctl() calls */
#include <linux/compat.h>
#include <linux/mount.h>
#include "ubifs.h"
/* Need to be kept consistent with checked flags in ioctl2ubifs() */
#define UBIFS_SETTABLE_IOCTL_FLAGS \
(FS_COMPR_FL | FS_SYNC_FL | FS_APPEND_FL | \
FS_IMMUTABLE_FL | FS_DIRSYNC_FL)
/* Need to be kept consistent with checked flags in ubifs2ioctl() */
#define UBIFS_GETTABLE_IOCTL_FLAGS \
(UBIFS_SETTABLE_IOCTL_FLAGS | FS_ENCRYPT_FL)
/**
* ubifs_set_inode_flags - set VFS inode flags.
* @inode: VFS inode to set flags for
*
* This function propagates flags from UBIFS inode object to VFS inode object.
*/
void ubifs_set_inode_flags(struct inode *inode)
{
unsigned int flags = ubifs_inode(inode)->flags;
inode->i_flags &= ~(S_SYNC | S_APPEND | S_IMMUTABLE | S_DIRSYNC |
S_ENCRYPTED);
if (flags & UBIFS_SYNC_FL)
inode->i_flags |= S_SYNC;
if (flags & UBIFS_APPEND_FL)
inode->i_flags |= S_APPEND;
if (flags & UBIFS_IMMUTABLE_FL)
inode->i_flags |= S_IMMUTABLE;
if (flags & UBIFS_DIRSYNC_FL)
inode->i_flags |= S_DIRSYNC;
if (flags & UBIFS_CRYPT_FL)
inode->i_flags |= S_ENCRYPTED;
}
/*
* ioctl2ubifs - convert ioctl inode flags to UBIFS inode flags.
* @ioctl_flags: flags to convert
*
* This function converts ioctl flags (@FS_COMPR_FL, etc) to UBIFS inode flags
* (@UBIFS_COMPR_FL, etc).
*/
static int ioctl2ubifs(int ioctl_flags)
{
int ubifs_flags = 0;
if (ioctl_flags & FS_COMPR_FL)
ubifs_flags |= UBIFS_COMPR_FL;
if (ioctl_flags & FS_SYNC_FL)
ubifs_flags |= UBIFS_SYNC_FL;
if (ioctl_flags & FS_APPEND_FL)
ubifs_flags |= UBIFS_APPEND_FL;
if (ioctl_flags & FS_IMMUTABLE_FL)
ubifs_flags |= UBIFS_IMMUTABLE_FL;
if (ioctl_flags & FS_DIRSYNC_FL)
ubifs_flags |= UBIFS_DIRSYNC_FL;
return ubifs_flags;
}
/*
* ubifs2ioctl - convert UBIFS inode flags to ioctl inode flags.
* @ubifs_flags: flags to convert
*
* This function converts UBIFS inode flags (@UBIFS_COMPR_FL, etc) to ioctl
* flags (@FS_COMPR_FL, etc).
*/
static int ubifs2ioctl(int ubifs_flags)
{
int ioctl_flags = 0;
if (ubifs_flags & UBIFS_COMPR_FL)
ioctl_flags |= FS_COMPR_FL;
if (ubifs_flags & UBIFS_SYNC_FL)
ioctl_flags |= FS_SYNC_FL;
if (ubifs_flags & UBIFS_APPEND_FL)
ioctl_flags |= FS_APPEND_FL;
if (ubifs_flags & UBIFS_IMMUTABLE_FL)
ioctl_flags |= FS_IMMUTABLE_FL;
if (ubifs_flags & UBIFS_DIRSYNC_FL)
ioctl_flags |= FS_DIRSYNC_FL;
if (ubifs_flags & UBIFS_CRYPT_FL)
ioctl_flags |= FS_ENCRYPT_FL;
return ioctl_flags;
}
static int setflags(struct inode *inode, int flags)
{
int oldflags, err, release;
struct ubifs_inode *ui = ubifs_inode(inode);
struct ubifs_info *c = inode->i_sb->s_fs_info;
struct ubifs_budget_req req = { .dirtied_ino = 1,
.dirtied_ino_d = ui->data_len };
err = ubifs_budget_space(c, &req);
if (err)
return err;
mutex_lock(&ui->ui_mutex);
oldflags = ubifs2ioctl(ui->flags);
err = vfs_ioc_setflags_prepare(inode, oldflags, flags);
if (err)
goto out_unlock;
ui->flags &= ~ioctl2ubifs(UBIFS_SETTABLE_IOCTL_FLAGS);
ui->flags |= ioctl2ubifs(flags);
ubifs_set_inode_flags(inode);
inode->i_ctime = current_time(inode);
release = ui->dirty;
mark_inode_dirty_sync(inode);
mutex_unlock(&ui->ui_mutex);
if (release)
ubifs_release_budget(c, &req);
if (IS_SYNC(inode))
err = write_inode_now(inode, 1);
return err;
out_unlock:
mutex_unlock(&ui->ui_mutex);
ubifs_release_budget(c, &req);
return err;
}
long ubifs_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
int flags, err;
struct inode *inode = file_inode(file);
switch (cmd) {
case FS_IOC_GETFLAGS:
flags = ubifs2ioctl(ubifs_inode(inode)->flags);
dbg_gen("get flags: %#x, i_flags %#x", flags, inode->i_flags);
return put_user(flags, (int __user *) arg);
case FS_IOC_SETFLAGS: {
if (IS_RDONLY(inode))
return -EROFS;
if (!inode_owner_or_capable(&init_user_ns, inode))
return -EACCES;
if (get_user(flags, (int __user *) arg))
return -EFAULT;
if (flags & ~UBIFS_GETTABLE_IOCTL_FLAGS)
return -EOPNOTSUPP;
flags &= UBIFS_SETTABLE_IOCTL_FLAGS;
if (!S_ISDIR(inode->i_mode))
flags &= ~FS_DIRSYNC_FL;
/*
* Make sure the file-system is read-write and make sure it
* will not become read-only while we are changing the flags.
*/
err = mnt_want_write_file(file);
if (err)
return err;
dbg_gen("set flags: %#x, i_flags %#x", flags, inode->i_flags);
err = setflags(inode, flags);
mnt_drop_write_file(file);
return err;
}
case FS_IOC_SET_ENCRYPTION_POLICY: {
struct ubifs_info *c = inode->i_sb->s_fs_info;
err = ubifs_enable_encryption(c);
if (err)
return err;
return fscrypt_ioctl_set_policy(file, (const void __user *)arg);
}
case FS_IOC_GET_ENCRYPTION_POLICY:
return fscrypt_ioctl_get_policy(file, (void __user *)arg);
case FS_IOC_GET_ENCRYPTION_POLICY_EX:
return fscrypt_ioctl_get_policy_ex(file, (void __user *)arg);
case FS_IOC_ADD_ENCRYPTION_KEY:
return fscrypt_ioctl_add_key(file, (void __user *)arg);
case FS_IOC_REMOVE_ENCRYPTION_KEY:
return fscrypt_ioctl_remove_key(file, (void __user *)arg);
case FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS:
return fscrypt_ioctl_remove_key_all_users(file,
(void __user *)arg);
case FS_IOC_GET_ENCRYPTION_KEY_STATUS:
return fscrypt_ioctl_get_key_status(file, (void __user *)arg);
case FS_IOC_GET_ENCRYPTION_NONCE:
return fscrypt_ioctl_get_nonce(file, (void __user *)arg);
default:
return -ENOTTY;
}
}
#ifdef CONFIG_COMPAT
long ubifs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
switch (cmd) {
case FS_IOC32_GETFLAGS:
cmd = FS_IOC_GETFLAGS;
break;
case FS_IOC32_SETFLAGS:
cmd = FS_IOC_SETFLAGS;
break;
case FS_IOC_SET_ENCRYPTION_POLICY:
case FS_IOC_GET_ENCRYPTION_POLICY:
case FS_IOC_GET_ENCRYPTION_POLICY_EX:
case FS_IOC_ADD_ENCRYPTION_KEY:
case FS_IOC_REMOVE_ENCRYPTION_KEY:
case FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS:
case FS_IOC_GET_ENCRYPTION_KEY_STATUS:
case FS_IOC_GET_ENCRYPTION_NONCE:
break;
default:
return -ENOIOCTLCMD;
}
return ubifs_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
}
#endif
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