linux/fs/ntfs3/namei.c
Christian Brauner 6c960e68aa
fs: port ->create() to pass mnt_idmap
Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19 09:24:25 +01:00

625 lines
13 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
*
* Copyright (C) 2019-2021 Paragon Software GmbH, All rights reserved.
*
*/
#include <linux/fs.h>
#include <linux/nls.h>
#include <linux/ctype.h>
#include <linux/posix_acl.h>
#include "debug.h"
#include "ntfs.h"
#include "ntfs_fs.h"
/*
* fill_name_de - Format NTFS_DE in @buf.
*/
int fill_name_de(struct ntfs_sb_info *sbi, void *buf, const struct qstr *name,
const struct cpu_str *uni)
{
int err;
struct NTFS_DE *e = buf;
u16 data_size;
struct ATTR_FILE_NAME *fname = (struct ATTR_FILE_NAME *)(e + 1);
#ifndef CONFIG_NTFS3_64BIT_CLUSTER
e->ref.high = fname->home.high = 0;
#endif
if (uni) {
#ifdef __BIG_ENDIAN
int ulen = uni->len;
__le16 *uname = fname->name;
const u16 *name_cpu = uni->name;
while (ulen--)
*uname++ = cpu_to_le16(*name_cpu++);
#else
memcpy(fname->name, uni->name, uni->len * sizeof(u16));
#endif
fname->name_len = uni->len;
} else {
/* Convert input string to unicode. */
err = ntfs_nls_to_utf16(sbi, name->name, name->len,
(struct cpu_str *)&fname->name_len,
NTFS_NAME_LEN, UTF16_LITTLE_ENDIAN);
if (err < 0)
return err;
}
fname->type = FILE_NAME_POSIX;
data_size = fname_full_size(fname);
e->size = cpu_to_le16(ALIGN(data_size, 8) + sizeof(struct NTFS_DE));
e->key_size = cpu_to_le16(data_size);
e->flags = 0;
e->res = 0;
return 0;
}
/*
* ntfs_lookup - inode_operations::lookup
*/
static struct dentry *ntfs_lookup(struct inode *dir, struct dentry *dentry,
u32 flags)
{
struct ntfs_inode *ni = ntfs_i(dir);
struct cpu_str *uni = __getname();
struct inode *inode;
int err;
if (!uni)
inode = ERR_PTR(-ENOMEM);
else {
err = ntfs_nls_to_utf16(ni->mi.sbi, dentry->d_name.name,
dentry->d_name.len, uni, NTFS_NAME_LEN,
UTF16_HOST_ENDIAN);
if (err < 0)
inode = ERR_PTR(err);
else {
ni_lock(ni);
inode = dir_search_u(dir, uni, NULL);
ni_unlock(ni);
}
__putname(uni);
}
return d_splice_alias(inode, dentry);
}
/*
* ntfs_create - inode_operations::create
*/
static int ntfs_create(struct mnt_idmap *idmap, struct inode *dir,
struct dentry *dentry, umode_t mode, bool excl)
{
struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
struct inode *inode;
inode = ntfs_create_inode(mnt_userns, dir, dentry, NULL, S_IFREG | mode,
0, NULL, 0, NULL);
return IS_ERR(inode) ? PTR_ERR(inode) : 0;
}
/*
* ntfs_mknod
*
* inode_operations::mknod
*/
static int ntfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
struct dentry *dentry, umode_t mode, dev_t rdev)
{
struct inode *inode;
inode = ntfs_create_inode(mnt_userns, dir, dentry, NULL, mode, rdev,
NULL, 0, NULL);
return IS_ERR(inode) ? PTR_ERR(inode) : 0;
}
/*
* ntfs_link - inode_operations::link
*/
static int ntfs_link(struct dentry *ode, struct inode *dir, struct dentry *de)
{
int err;
struct inode *inode = d_inode(ode);
struct ntfs_inode *ni = ntfs_i(inode);
if (S_ISDIR(inode->i_mode))
return -EPERM;
if (inode->i_nlink >= NTFS_LINK_MAX)
return -EMLINK;
ni_lock_dir(ntfs_i(dir));
if (inode != dir)
ni_lock(ni);
inc_nlink(inode);
ihold(inode);
err = ntfs_link_inode(inode, de);
if (!err) {
dir->i_ctime = dir->i_mtime = inode->i_ctime =
current_time(dir);
mark_inode_dirty(inode);
mark_inode_dirty(dir);
d_instantiate(de, inode);
} else {
drop_nlink(inode);
iput(inode);
}
if (inode != dir)
ni_unlock(ni);
ni_unlock(ntfs_i(dir));
return err;
}
/*
* ntfs_unlink - inode_operations::unlink
*/
static int ntfs_unlink(struct inode *dir, struct dentry *dentry)
{
struct ntfs_inode *ni = ntfs_i(dir);
int err;
ni_lock_dir(ni);
err = ntfs_unlink_inode(dir, dentry);
ni_unlock(ni);
return err;
}
/*
* ntfs_symlink - inode_operations::symlink
*/
static int ntfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
struct dentry *dentry, const char *symname)
{
u32 size = strlen(symname);
struct inode *inode;
inode = ntfs_create_inode(mnt_userns, dir, dentry, NULL, S_IFLNK | 0777,
0, symname, size, NULL);
return IS_ERR(inode) ? PTR_ERR(inode) : 0;
}
/*
* ntfs_mkdir- inode_operations::mkdir
*/
static int ntfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
struct dentry *dentry, umode_t mode)
{
struct inode *inode;
inode = ntfs_create_inode(mnt_userns, dir, dentry, NULL, S_IFDIR | mode,
0, NULL, 0, NULL);
return IS_ERR(inode) ? PTR_ERR(inode) : 0;
}
/*
* ntfs_rmdir - inode_operations::rmdir
*/
static int ntfs_rmdir(struct inode *dir, struct dentry *dentry)
{
struct ntfs_inode *ni = ntfs_i(dir);
int err;
ni_lock_dir(ni);
err = ntfs_unlink_inode(dir, dentry);
ni_unlock(ni);
return err;
}
/*
* ntfs_rename - inode_operations::rename
*/
static int ntfs_rename(struct user_namespace *mnt_userns, struct inode *dir,
struct dentry *dentry, struct inode *new_dir,
struct dentry *new_dentry, u32 flags)
{
int err;
struct super_block *sb = dir->i_sb;
struct ntfs_sb_info *sbi = sb->s_fs_info;
struct ntfs_inode *dir_ni = ntfs_i(dir);
struct ntfs_inode *new_dir_ni = ntfs_i(new_dir);
struct inode *inode = d_inode(dentry);
struct ntfs_inode *ni = ntfs_i(inode);
struct inode *new_inode = d_inode(new_dentry);
struct NTFS_DE *de, *new_de;
bool is_same, is_bad;
/*
* de - memory of PATH_MAX bytes:
* [0-1024) - original name (dentry->d_name)
* [1024-2048) - paired to original name, usually DOS variant of dentry->d_name
* [2048-3072) - new name (new_dentry->d_name)
*/
static_assert(SIZEOF_ATTRIBUTE_FILENAME_MAX + SIZEOF_RESIDENT < 1024);
static_assert(SIZEOF_ATTRIBUTE_FILENAME_MAX + sizeof(struct NTFS_DE) <
1024);
static_assert(PATH_MAX >= 4 * 1024);
if (flags & ~RENAME_NOREPLACE)
return -EINVAL;
is_same = dentry->d_name.len == new_dentry->d_name.len &&
!memcmp(dentry->d_name.name, new_dentry->d_name.name,
dentry->d_name.len);
if (is_same && dir == new_dir) {
/* Nothing to do. */
return 0;
}
if (ntfs_is_meta_file(sbi, inode->i_ino)) {
/* Should we print an error? */
return -EINVAL;
}
if (new_inode) {
/* Target name exists. Unlink it. */
dget(new_dentry);
ni_lock_dir(new_dir_ni);
err = ntfs_unlink_inode(new_dir, new_dentry);
ni_unlock(new_dir_ni);
dput(new_dentry);
if (err)
return err;
}
/* Allocate PATH_MAX bytes. */
de = __getname();
if (!de)
return -ENOMEM;
/* Translate dentry->d_name into unicode form. */
err = fill_name_de(sbi, de, &dentry->d_name, NULL);
if (err < 0)
goto out;
if (is_same) {
/* Reuse 'de'. */
new_de = de;
} else {
/* Translate new_dentry->d_name into unicode form. */
new_de = Add2Ptr(de, 2048);
err = fill_name_de(sbi, new_de, &new_dentry->d_name, NULL);
if (err < 0)
goto out;
}
ni_lock_dir(dir_ni);
ni_lock(ni);
if (dir_ni != new_dir_ni)
ni_lock_dir2(new_dir_ni);
is_bad = false;
err = ni_rename(dir_ni, new_dir_ni, ni, de, new_de, &is_bad);
if (is_bad) {
/* Restore after failed rename failed too. */
_ntfs_bad_inode(inode);
} else if (!err) {
inode->i_ctime = dir->i_ctime = dir->i_mtime =
current_time(dir);
mark_inode_dirty(inode);
mark_inode_dirty(dir);
if (dir != new_dir) {
new_dir->i_mtime = new_dir->i_ctime = dir->i_ctime;
mark_inode_dirty(new_dir);
}
if (IS_DIRSYNC(dir))
ntfs_sync_inode(dir);
if (IS_DIRSYNC(new_dir))
ntfs_sync_inode(inode);
}
if (dir_ni != new_dir_ni)
ni_unlock(new_dir_ni);
ni_unlock(ni);
ni_unlock(dir_ni);
out:
__putname(de);
return err;
}
/*
* ntfs_atomic_open
*
* inode_operations::atomic_open
*/
static int ntfs_atomic_open(struct inode *dir, struct dentry *dentry,
struct file *file, u32 flags, umode_t mode)
{
int err;
struct inode *inode;
struct ntfs_fnd *fnd = NULL;
struct ntfs_inode *ni = ntfs_i(dir);
struct dentry *d = NULL;
struct cpu_str *uni = __getname();
bool locked = false;
if (!uni)
return -ENOMEM;
err = ntfs_nls_to_utf16(ni->mi.sbi, dentry->d_name.name,
dentry->d_name.len, uni, NTFS_NAME_LEN,
UTF16_HOST_ENDIAN);
if (err < 0)
goto out;
#ifdef CONFIG_NTFS3_FS_POSIX_ACL
if (IS_POSIXACL(dir)) {
/*
* Load in cache current acl to avoid ni_lock(dir):
* ntfs_create_inode -> ntfs_init_acl -> posix_acl_create ->
* ntfs_get_acl -> ntfs_get_acl_ex -> ni_lock
*/
struct posix_acl *p = get_inode_acl(dir, ACL_TYPE_DEFAULT);
if (IS_ERR(p)) {
err = PTR_ERR(p);
goto out;
}
posix_acl_release(p);
}
#endif
if (d_in_lookup(dentry)) {
ni_lock_dir(ni);
locked = true;
fnd = fnd_get();
if (!fnd) {
err = -ENOMEM;
goto out1;
}
d = d_splice_alias(dir_search_u(dir, uni, fnd), dentry);
if (IS_ERR(d)) {
err = PTR_ERR(d);
d = NULL;
goto out2;
}
if (d)
dentry = d;
}
if (!(flags & O_CREAT) || d_really_is_positive(dentry)) {
err = finish_no_open(file, d);
goto out2;
}
file->f_mode |= FMODE_CREATED;
/*
* fnd contains tree's path to insert to.
* If fnd is not NULL then dir is locked.
*/
/*
* Unfortunately I don't know how to get here correct 'struct nameidata *nd'
* or 'struct user_namespace *mnt_userns'.
* See atomic_open in fs/namei.c.
* This is why xfstest/633 failed.
* Looks like ntfs_atomic_open must accept 'struct user_namespace *mnt_userns' as argument.
*/
inode = ntfs_create_inode(&init_user_ns, dir, dentry, uni, mode, 0,
NULL, 0, fnd);
err = IS_ERR(inode) ? PTR_ERR(inode)
: finish_open(file, dentry, ntfs_file_open);
dput(d);
out2:
fnd_put(fnd);
out1:
if (locked)
ni_unlock(ni);
out:
__putname(uni);
return err;
}
struct dentry *ntfs3_get_parent(struct dentry *child)
{
struct inode *inode = d_inode(child);
struct ntfs_inode *ni = ntfs_i(inode);
struct ATTR_LIST_ENTRY *le = NULL;
struct ATTRIB *attr = NULL;
struct ATTR_FILE_NAME *fname;
while ((attr = ni_find_attr(ni, attr, &le, ATTR_NAME, NULL, 0, NULL,
NULL))) {
fname = resident_data_ex(attr, SIZEOF_ATTRIBUTE_FILENAME);
if (!fname)
continue;
return d_obtain_alias(
ntfs_iget5(inode->i_sb, &fname->home, NULL));
}
return ERR_PTR(-ENOENT);
}
/*
* dentry_operations::d_hash
*/
static int ntfs_d_hash(const struct dentry *dentry, struct qstr *name)
{
struct ntfs_sb_info *sbi;
const char *n = name->name;
unsigned int len = name->len;
unsigned long hash;
struct cpu_str *uni;
unsigned int c;
int err;
/* First try fast implementation. */
hash = init_name_hash(dentry);
for (;;) {
if (!len--) {
name->hash = end_name_hash(hash);
return 0;
}
c = *n++;
if (c >= 0x80)
break;
hash = partial_name_hash(toupper(c), hash);
}
/*
* Try slow way with current upcase table
*/
uni = __getname();
if (!uni)
return -ENOMEM;
sbi = dentry->d_sb->s_fs_info;
err = ntfs_nls_to_utf16(sbi, name->name, name->len, uni, NTFS_NAME_LEN,
UTF16_HOST_ENDIAN);
if (err < 0)
goto out;
if (!err) {
err = -EINVAL;
goto out;
}
hash = ntfs_names_hash(uni->name, uni->len, sbi->upcase,
init_name_hash(dentry));
name->hash = end_name_hash(hash);
err = 0;
out:
__putname(uni);
return err;
}
/*
* dentry_operations::d_compare
*/
static int ntfs_d_compare(const struct dentry *dentry, unsigned int len1,
const char *str, const struct qstr *name)
{
struct ntfs_sb_info *sbi;
int ret;
const char *n1 = str;
const char *n2 = name->name;
unsigned int len2 = name->len;
unsigned int lm = min(len1, len2);
unsigned char c1, c2;
struct cpu_str *uni1;
struct le_str *uni2;
/* First try fast implementation. */
for (;;) {
if (!lm--)
return len1 != len2;
if ((c1 = *n1++) == (c2 = *n2++))
continue;
if (c1 >= 0x80 || c2 >= 0x80)
break;
if (toupper(c1) != toupper(c2))
return 1;
}
/*
* Try slow way with current upcase table
*/
sbi = dentry->d_sb->s_fs_info;
uni1 = __getname();
if (!uni1)
return -ENOMEM;
ret = ntfs_nls_to_utf16(sbi, str, len1, uni1, NTFS_NAME_LEN,
UTF16_HOST_ENDIAN);
if (ret < 0)
goto out;
if (!ret) {
ret = -EINVAL;
goto out;
}
uni2 = Add2Ptr(uni1, 2048);
ret = ntfs_nls_to_utf16(sbi, name->name, name->len,
(struct cpu_str *)uni2, NTFS_NAME_LEN,
UTF16_LITTLE_ENDIAN);
if (ret < 0)
goto out;
if (!ret) {
ret = -EINVAL;
goto out;
}
ret = !ntfs_cmp_names_cpu(uni1, uni2, sbi->upcase, false) ? 0 : 1;
out:
__putname(uni1);
return ret;
}
// clang-format off
const struct inode_operations ntfs_dir_inode_operations = {
.lookup = ntfs_lookup,
.create = ntfs_create,
.link = ntfs_link,
.unlink = ntfs_unlink,
.symlink = ntfs_symlink,
.mkdir = ntfs_mkdir,
.rmdir = ntfs_rmdir,
.mknod = ntfs_mknod,
.rename = ntfs_rename,
.permission = ntfs_permission,
.get_inode_acl = ntfs_get_acl,
.set_acl = ntfs_set_acl,
.setattr = ntfs3_setattr,
.getattr = ntfs_getattr,
.listxattr = ntfs_listxattr,
.atomic_open = ntfs_atomic_open,
.fiemap = ntfs_fiemap,
};
const struct inode_operations ntfs_special_inode_operations = {
.setattr = ntfs3_setattr,
.getattr = ntfs_getattr,
.listxattr = ntfs_listxattr,
.get_inode_acl = ntfs_get_acl,
.set_acl = ntfs_set_acl,
};
const struct dentry_operations ntfs_dentry_ops = {
.d_hash = ntfs_d_hash,
.d_compare = ntfs_d_compare,
};
// clang-format on