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2f221d6f7b
linux/fs/hpfs/inode.c
Christian Brauner 2f221d6f7b
attr: handle idmapped mounts 
When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into 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.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. 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/20210121131959.646623-8-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>
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
/*
* linux/fs/hpfs/inode.c
*
* Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
*
* inode VFS functions
*/
#include <linux/slab.h>
#include <linux/user_namespace.h>
#include "hpfs_fn.h"
void hpfs_init_inode(struct inode *i)
{
struct super_block *sb = i->i_sb;
struct hpfs_inode_info *hpfs_inode = hpfs_i(i);
i->i_uid = hpfs_sb(sb)->sb_uid;
i->i_gid = hpfs_sb(sb)->sb_gid;
i->i_mode = hpfs_sb(sb)->sb_mode;
i->i_size = -1;
i->i_blocks = -1;
hpfs_inode->i_dno = 0;
hpfs_inode->i_n_secs = 0;
hpfs_inode->i_file_sec = 0;
hpfs_inode->i_disk_sec = 0;
hpfs_inode->i_dpos = 0;
hpfs_inode->i_dsubdno = 0;
hpfs_inode->i_ea_mode = 0;
hpfs_inode->i_ea_uid = 0;
hpfs_inode->i_ea_gid = 0;
hpfs_inode->i_ea_size = 0;
hpfs_inode->i_rddir_off = NULL;
hpfs_inode->i_dirty = 0;
i->i_ctime.tv_sec = i->i_ctime.tv_nsec = 0;
i->i_mtime.tv_sec = i->i_mtime.tv_nsec = 0;
i->i_atime.tv_sec = i->i_atime.tv_nsec = 0;
}
void hpfs_read_inode(struct inode *i)
{
struct buffer_head *bh;
struct fnode *fnode;
struct super_block *sb = i->i_sb;
struct hpfs_inode_info *hpfs_inode = hpfs_i(i);
void *ea;
int ea_size;
if (!(fnode = hpfs_map_fnode(sb, i->i_ino, &bh))) {
/*i->i_mode |= S_IFREG;
i->i_mode &= ~0111;
i->i_op = &hpfs_file_iops;
i->i_fop = &hpfs_file_ops;
clear_nlink(i);*/
make_bad_inode(i);
return;
}
if (hpfs_sb(i->i_sb)->sb_eas) {
if ((ea = hpfs_get_ea(i->i_sb, fnode, "UID", &ea_size))) {
if (ea_size == 2) {
i_uid_write(i, le16_to_cpu(*(__le16*)ea));
hpfs_inode->i_ea_uid = 1;
}
kfree(ea);
}
if ((ea = hpfs_get_ea(i->i_sb, fnode, "GID", &ea_size))) {
if (ea_size == 2) {
i_gid_write(i, le16_to_cpu(*(__le16*)ea));
hpfs_inode->i_ea_gid = 1;
}
kfree(ea);
}
if ((ea = hpfs_get_ea(i->i_sb, fnode, "SYMLINK", &ea_size))) {
kfree(ea);
i->i_mode = S_IFLNK | 0777;
i->i_op = &page_symlink_inode_operations;
inode_nohighmem(i);
i->i_data.a_ops = &hpfs_symlink_aops;
set_nlink(i, 1);
i->i_size = ea_size;
i->i_blocks = 1;
brelse(bh);
return;
}
if ((ea = hpfs_get_ea(i->i_sb, fnode, "MODE", &ea_size))) {
int rdev = 0;
umode_t mode = hpfs_sb(sb)->sb_mode;
if (ea_size == 2) {
mode = le16_to_cpu(*(__le16*)ea);
hpfs_inode->i_ea_mode = 1;
}
kfree(ea);
i->i_mode = mode;
if (S_ISBLK(mode) || S_ISCHR(mode)) {
if ((ea = hpfs_get_ea(i->i_sb, fnode, "DEV", &ea_size))) {
if (ea_size == 4)
rdev = le32_to_cpu(*(__le32*)ea);
kfree(ea);
}
}
if (S_ISBLK(mode) || S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
brelse(bh);
set_nlink(i, 1);
i->i_size = 0;
i->i_blocks = 1;
init_special_inode(i, mode,
new_decode_dev(rdev));
return;
}
}
}
if (fnode_is_dir(fnode)) {
int n_dnodes, n_subdirs;
i->i_mode |= S_IFDIR;
i->i_op = &hpfs_dir_iops;
i->i_fop = &hpfs_dir_ops;
hpfs_inode->i_parent_dir = le32_to_cpu(fnode->up);
hpfs_inode->i_dno = le32_to_cpu(fnode->u.external[0].disk_secno);
if (hpfs_sb(sb)->sb_chk >= 2) {
struct buffer_head *bh0;
if (hpfs_map_fnode(sb, hpfs_inode->i_parent_dir, &bh0)) brelse(bh0);
}
n_dnodes = 0; n_subdirs = 0;
hpfs_count_dnodes(i->i_sb, hpfs_inode->i_dno, &n_dnodes, &n_subdirs, NULL);
i->i_blocks = 4 * n_dnodes;
i->i_size = 2048 * n_dnodes;
set_nlink(i, 2 + n_subdirs);
} else {
i->i_mode |= S_IFREG;
if (!hpfs_inode->i_ea_mode) i->i_mode &= ~0111;
i->i_op = &hpfs_file_iops;
i->i_fop = &hpfs_file_ops;
set_nlink(i, 1);
i->i_size = le32_to_cpu(fnode->file_size);
i->i_blocks = ((i->i_size + 511) >> 9) + 1;
i->i_data.a_ops = &hpfs_aops;
hpfs_i(i)->mmu_private = i->i_size;
}
brelse(bh);
}
static void hpfs_write_inode_ea(struct inode *i, struct fnode *fnode)
{
struct hpfs_inode_info *hpfs_inode = hpfs_i(i);
/*if (le32_to_cpu(fnode->acl_size_l) || le16_to_cpu(fnode->acl_size_s)) {
Some unknown structures like ACL may be in fnode,
we'd better not overwrite them
hpfs_error(i->i_sb, "fnode %08x has some unknown HPFS386 structures", i->i_ino);
} else*/ if (hpfs_sb(i->i_sb)->sb_eas >= 2) {
__le32 ea;
if (!uid_eq(i->i_uid, hpfs_sb(i->i_sb)->sb_uid) || hpfs_inode->i_ea_uid) {
ea = cpu_to_le32(i_uid_read(i));
hpfs_set_ea(i, fnode, "UID", (char*)&ea, 2);
hpfs_inode->i_ea_uid = 1;
}
if (!gid_eq(i->i_gid, hpfs_sb(i->i_sb)->sb_gid) || hpfs_inode->i_ea_gid) {
ea = cpu_to_le32(i_gid_read(i));
hpfs_set_ea(i, fnode, "GID", (char *)&ea, 2);
hpfs_inode->i_ea_gid = 1;
}
if (!S_ISLNK(i->i_mode))
if ((i->i_mode != ((hpfs_sb(i->i_sb)->sb_mode & ~(S_ISDIR(i->i_mode) ? 0 : 0111))
| (S_ISDIR(i->i_mode) ? S_IFDIR : S_IFREG))
&& i->i_mode != ((hpfs_sb(i->i_sb)->sb_mode & ~(S_ISDIR(i->i_mode) ? 0222 : 0333))
| (S_ISDIR(i->i_mode) ? S_IFDIR : S_IFREG))) || hpfs_inode->i_ea_mode) {
ea = cpu_to_le32(i->i_mode);
/* sick, but legal */
hpfs_set_ea(i, fnode, "MODE", (char *)&ea, 2);
hpfs_inode->i_ea_mode = 1;
}
if (S_ISBLK(i->i_mode) || S_ISCHR(i->i_mode)) {
ea = cpu_to_le32(new_encode_dev(i->i_rdev));
hpfs_set_ea(i, fnode, "DEV", (char *)&ea, 4);
}
}
}
void hpfs_write_inode(struct inode *i)
{
struct hpfs_inode_info *hpfs_inode = hpfs_i(i);
struct inode *parent;
if (i->i_ino == hpfs_sb(i->i_sb)->sb_root) return;
if (hpfs_inode->i_rddir_off && !atomic_read(&i->i_count)) {
if (*hpfs_inode->i_rddir_off)
pr_err("write_inode: some position still there\n");
kfree(hpfs_inode->i_rddir_off);
hpfs_inode->i_rddir_off = NULL;
}
if (!i->i_nlink) {
return;
}
parent = iget_locked(i->i_sb, hpfs_inode->i_parent_dir);
if (parent) {
hpfs_inode->i_dirty = 0;
if (parent->i_state & I_NEW) {
hpfs_init_inode(parent);
hpfs_read_inode(parent);
unlock_new_inode(parent);
}
hpfs_write_inode_nolock(i);
iput(parent);
}
}
void hpfs_write_inode_nolock(struct inode *i)
{
struct hpfs_inode_info *hpfs_inode = hpfs_i(i);
struct buffer_head *bh;
struct fnode *fnode;
struct quad_buffer_head qbh;
struct hpfs_dirent *de;
if (i->i_ino == hpfs_sb(i->i_sb)->sb_root) return;
if (!(fnode = hpfs_map_fnode(i->i_sb, i->i_ino, &bh))) return;
if (i->i_ino != hpfs_sb(i->i_sb)->sb_root && i->i_nlink) {
if (!(de = map_fnode_dirent(i->i_sb, i->i_ino, fnode, &qbh))) {
brelse(bh);
return;
}
} else de = NULL;
if (S_ISREG(i->i_mode)) {
fnode->file_size = cpu_to_le32(i->i_size);
if (de) de->file_size = cpu_to_le32(i->i_size);
} else if (S_ISDIR(i->i_mode)) {
fnode->file_size = cpu_to_le32(0);
if (de) de->file_size = cpu_to_le32(0);
}
hpfs_write_inode_ea(i, fnode);
if (de) {
de->write_date = cpu_to_le32(gmt_to_local(i->i_sb, i->i_mtime.tv_sec));
de->read_date = cpu_to_le32(gmt_to_local(i->i_sb, i->i_atime.tv_sec));
de->creation_date = cpu_to_le32(gmt_to_local(i->i_sb, i->i_ctime.tv_sec));
de->read_only = !(i->i_mode & 0222);
de->ea_size = cpu_to_le32(hpfs_inode->i_ea_size);
hpfs_mark_4buffers_dirty(&qbh);
hpfs_brelse4(&qbh);
}
if (S_ISDIR(i->i_mode)) {
if ((de = map_dirent(i, hpfs_inode->i_dno, "\001\001", 2, NULL, &qbh))) {
de->write_date = cpu_to_le32(gmt_to_local(i->i_sb, i->i_mtime.tv_sec));
de->read_date = cpu_to_le32(gmt_to_local(i->i_sb, i->i_atime.tv_sec));
de->creation_date = cpu_to_le32(gmt_to_local(i->i_sb, i->i_ctime.tv_sec));
de->read_only = !(i->i_mode & 0222);
de->ea_size = cpu_to_le32(/*hpfs_inode->i_ea_size*/0);
de->file_size = cpu_to_le32(0);
hpfs_mark_4buffers_dirty(&qbh);
hpfs_brelse4(&qbh);
} else
hpfs_error(i->i_sb,
"directory %08lx doesn't have '.' entry",
(unsigned long)i->i_ino);
}
mark_buffer_dirty(bh);
brelse(bh);
}
int hpfs_setattr(struct dentry *dentry, struct iattr *attr)
{
struct inode *inode = d_inode(dentry);
int error = -EINVAL;
hpfs_lock(inode->i_sb);
if (inode->i_ino == hpfs_sb(inode->i_sb)->sb_root)
goto out_unlock;
if ((attr->ia_valid & ATTR_UID) &&
from_kuid(&init_user_ns, attr->ia_uid) >= 0x10000)
goto out_unlock;
if ((attr->ia_valid & ATTR_GID) &&
from_kgid(&init_user_ns, attr->ia_gid) >= 0x10000)
goto out_unlock;
if ((attr->ia_valid & ATTR_SIZE) && attr->ia_size > inode->i_size)
goto out_unlock;
error = setattr_prepare(&init_user_ns, dentry, attr);
if (error)
goto out_unlock;
if ((attr->ia_valid & ATTR_SIZE) &&
attr->ia_size != i_size_read(inode)) {
error = inode_newsize_ok(inode, attr->ia_size);
if (error)
goto out_unlock;
truncate_setsize(inode, attr->ia_size);
hpfs_truncate(inode);
}
setattr_copy(&init_user_ns, inode, attr);
hpfs_write_inode(inode);
out_unlock:
hpfs_unlock(inode->i_sb);
return error;
}
void hpfs_write_if_changed(struct inode *inode)
{
struct hpfs_inode_info *hpfs_inode = hpfs_i(inode);
if (hpfs_inode->i_dirty)
hpfs_write_inode(inode);
}
void hpfs_evict_inode(struct inode *inode)
{
truncate_inode_pages_final(&inode->i_data);
clear_inode(inode);
if (!inode->i_nlink) {
hpfs_lock(inode->i_sb);
hpfs_remove_fnode(inode->i_sb, inode->i_ino);
hpfs_unlock(inode->i_sb);
}
}
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