linux-zen-desktop/fs/reiserfs/xattr_acl.c

412 lines
9.8 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/capability.h>
#include <linux/fs.h>
#include <linux/posix_acl.h>
#include "reiserfs.h"
#include <linux/errno.h>
#include <linux/pagemap.h>
#include <linux/xattr.h>
#include <linux/slab.h>
#include <linux/posix_acl_xattr.h>
#include "xattr.h"
#include "acl.h"
#include <linux/uaccess.h>
static int __reiserfs_set_acl(struct reiserfs_transaction_handle *th,
struct inode *inode, int type,
struct posix_acl *acl);
int
reiserfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
struct posix_acl *acl, int type)
{
int error, error2;
struct reiserfs_transaction_handle th;
size_t jcreate_blocks;
int size = acl ? posix_acl_xattr_size(acl->a_count) : 0;
int update_mode = 0;
struct inode *inode = d_inode(dentry);
umode_t mode = inode->i_mode;
/*
* Pessimism: We can't assume that anything from the xattr root up
* has been created.
*/
jcreate_blocks = reiserfs_xattr_jcreate_nblocks(inode) +
reiserfs_xattr_nblocks(inode, size) * 2;
reiserfs_write_lock(inode->i_sb);
error = journal_begin(&th, inode->i_sb, jcreate_blocks);
reiserfs_write_unlock(inode->i_sb);
if (error == 0) {
if (type == ACL_TYPE_ACCESS && acl) {
error = posix_acl_update_mode(&nop_mnt_idmap, inode,
&mode, &acl);
if (error)
goto unlock;
update_mode = 1;
}
error = __reiserfs_set_acl(&th, inode, type, acl);
if (!error && update_mode)
inode->i_mode = mode;
unlock:
reiserfs_write_lock(inode->i_sb);
error2 = journal_end(&th);
reiserfs_write_unlock(inode->i_sb);
if (error2)
error = error2;
}
return error;
}
/*
* Convert from filesystem to in-memory representation.
*/
static struct posix_acl *reiserfs_posix_acl_from_disk(const void *value, size_t size)
{
const char *end = (char *)value + size;
int n, count;
struct posix_acl *acl;
if (!value)
return NULL;
if (size < sizeof(reiserfs_acl_header))
return ERR_PTR(-EINVAL);
if (((reiserfs_acl_header *) value)->a_version !=
cpu_to_le32(REISERFS_ACL_VERSION))
return ERR_PTR(-EINVAL);
value = (char *)value + sizeof(reiserfs_acl_header);
count = reiserfs_acl_count(size);
if (count < 0)
return ERR_PTR(-EINVAL);
if (count == 0)
return NULL;
acl = posix_acl_alloc(count, GFP_NOFS);
if (!acl)
return ERR_PTR(-ENOMEM);
for (n = 0; n < count; n++) {
reiserfs_acl_entry *entry = (reiserfs_acl_entry *) value;
if ((char *)value + sizeof(reiserfs_acl_entry_short) > end)
goto fail;
acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
switch (acl->a_entries[n].e_tag) {
case ACL_USER_OBJ:
case ACL_GROUP_OBJ:
case ACL_MASK:
case ACL_OTHER:
value = (char *)value +
sizeof(reiserfs_acl_entry_short);
break;
case ACL_USER:
value = (char *)value + sizeof(reiserfs_acl_entry);
if ((char *)value > end)
goto fail;
acl->a_entries[n].e_uid =
make_kuid(&init_user_ns,
le32_to_cpu(entry->e_id));
break;
case ACL_GROUP:
value = (char *)value + sizeof(reiserfs_acl_entry);
if ((char *)value > end)
goto fail;
acl->a_entries[n].e_gid =
make_kgid(&init_user_ns,
le32_to_cpu(entry->e_id));
break;
default:
goto fail;
}
}
if (value != end)
goto fail;
return acl;
fail:
posix_acl_release(acl);
return ERR_PTR(-EINVAL);
}
/*
* Convert from in-memory to filesystem representation.
*/
static void *reiserfs_posix_acl_to_disk(const struct posix_acl *acl, size_t * size)
{
reiserfs_acl_header *ext_acl;
char *e;
int n;
*size = reiserfs_acl_size(acl->a_count);
ext_acl = kmalloc(sizeof(reiserfs_acl_header) +
acl->a_count *
sizeof(reiserfs_acl_entry),
GFP_NOFS);
if (!ext_acl)
return ERR_PTR(-ENOMEM);
ext_acl->a_version = cpu_to_le32(REISERFS_ACL_VERSION);
e = (char *)ext_acl + sizeof(reiserfs_acl_header);
for (n = 0; n < acl->a_count; n++) {
const struct posix_acl_entry *acl_e = &acl->a_entries[n];
reiserfs_acl_entry *entry = (reiserfs_acl_entry *) e;
entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
switch (acl->a_entries[n].e_tag) {
case ACL_USER:
entry->e_id = cpu_to_le32(
from_kuid(&init_user_ns, acl_e->e_uid));
e += sizeof(reiserfs_acl_entry);
break;
case ACL_GROUP:
entry->e_id = cpu_to_le32(
from_kgid(&init_user_ns, acl_e->e_gid));
e += sizeof(reiserfs_acl_entry);
break;
case ACL_USER_OBJ:
case ACL_GROUP_OBJ:
case ACL_MASK:
case ACL_OTHER:
e += sizeof(reiserfs_acl_entry_short);
break;
default:
goto fail;
}
}
return (char *)ext_acl;
fail:
kfree(ext_acl);
return ERR_PTR(-EINVAL);
}
/*
* Inode operation get_posix_acl().
*
* inode->i_mutex: down
* BKL held [before 2.5.x]
*/
struct posix_acl *reiserfs_get_acl(struct inode *inode, int type, bool rcu)
{
char *name, *value;
struct posix_acl *acl;
int size;
int retval;
if (rcu)
return ERR_PTR(-ECHILD);
switch (type) {
case ACL_TYPE_ACCESS:
name = XATTR_NAME_POSIX_ACL_ACCESS;
break;
case ACL_TYPE_DEFAULT:
name = XATTR_NAME_POSIX_ACL_DEFAULT;
break;
default:
BUG();
}
size = reiserfs_xattr_get(inode, name, NULL, 0);
if (size < 0) {
if (size == -ENODATA || size == -ENOSYS)
return NULL;
return ERR_PTR(size);
}
value = kmalloc(size, GFP_NOFS);
if (!value)
return ERR_PTR(-ENOMEM);
retval = reiserfs_xattr_get(inode, name, value, size);
if (retval == -ENODATA || retval == -ENOSYS) {
/*
* This shouldn't actually happen as it should have
* been caught above.. but just in case
*/
acl = NULL;
} else if (retval < 0) {
acl = ERR_PTR(retval);
} else {
acl = reiserfs_posix_acl_from_disk(value, retval);
}
kfree(value);
return acl;
}
/*
* Inode operation set_posix_acl().
*
* inode->i_mutex: down
* BKL held [before 2.5.x]
*/
static int
__reiserfs_set_acl(struct reiserfs_transaction_handle *th, struct inode *inode,
int type, struct posix_acl *acl)
{
char *name;
void *value = NULL;
size_t size = 0;
int error;
switch (type) {
case ACL_TYPE_ACCESS:
name = XATTR_NAME_POSIX_ACL_ACCESS;
break;
case ACL_TYPE_DEFAULT:
name = XATTR_NAME_POSIX_ACL_DEFAULT;
if (!S_ISDIR(inode->i_mode))
return acl ? -EACCES : 0;
break;
default:
return -EINVAL;
}
if (acl) {
value = reiserfs_posix_acl_to_disk(acl, &size);
if (IS_ERR(value))
return (int)PTR_ERR(value);
}
error = reiserfs_xattr_set_handle(th, inode, name, value, size, 0);
/*
* Ensure that the inode gets dirtied if we're only using
* the mode bits and an old ACL didn't exist. We don't need
* to check if the inode is hashed here since we won't get
* called by reiserfs_inherit_default_acl().
*/
if (error == -ENODATA) {
error = 0;
if (type == ACL_TYPE_ACCESS) {
inode->i_ctime = current_time(inode);
mark_inode_dirty(inode);
}
}
kfree(value);
if (!error)
set_cached_acl(inode, type, acl);
return error;
}
/*
* dir->i_mutex: locked,
* inode is new and not released into the wild yet
*/
int
reiserfs_inherit_default_acl(struct reiserfs_transaction_handle *th,
struct inode *dir, struct dentry *dentry,
struct inode *inode)
{
struct posix_acl *default_acl, *acl;
int err = 0;
/* ACLs only get applied to files and directories */
if (S_ISLNK(inode->i_mode))
return 0;
/*
* ACLs can only be used on "new" objects, so if it's an old object
* there is nothing to inherit from
*/
if (get_inode_sd_version(dir) == STAT_DATA_V1)
goto apply_umask;
/*
* Don't apply ACLs to objects in the .reiserfs_priv tree.. This
* would be useless since permissions are ignored, and a pain because
* it introduces locking cycles
*/
if (IS_PRIVATE(inode))
goto apply_umask;
err = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
if (err)
return err;
if (default_acl) {
err = __reiserfs_set_acl(th, inode, ACL_TYPE_DEFAULT,
default_acl);
posix_acl_release(default_acl);
}
if (acl) {
if (!err)
err = __reiserfs_set_acl(th, inode, ACL_TYPE_ACCESS,
acl);
posix_acl_release(acl);
}
return err;
apply_umask:
/* no ACL, apply umask */
inode->i_mode &= ~current_umask();
return err;
}
/* This is used to cache the default acl before a new object is created.
* The biggest reason for this is to get an idea of how many blocks will
* actually be required for the create operation if we must inherit an ACL.
* An ACL write can add up to 3 object creations and an additional file write
* so we'd prefer not to reserve that many blocks in the journal if we can.
* It also has the advantage of not loading the ACL with a transaction open,
* this may seem silly, but if the owner of the directory is doing the
* creation, the ACL may not be loaded since the permissions wouldn't require
* it.
* We return the number of blocks required for the transaction.
*/
int reiserfs_cache_default_acl(struct inode *inode)
{
struct posix_acl *acl;
int nblocks = 0;
if (IS_PRIVATE(inode))
return 0;
acl = get_inode_acl(inode, ACL_TYPE_DEFAULT);
if (acl && !IS_ERR(acl)) {
int size = reiserfs_acl_size(acl->a_count);
/* Other xattrs can be created during inode creation. We don't
* want to claim too many blocks, so we check to see if we
* need to create the tree to the xattrs, and then we
* just want two files. */
nblocks = reiserfs_xattr_jcreate_nblocks(inode);
nblocks += JOURNAL_BLOCKS_PER_OBJECT(inode->i_sb);
REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
/* We need to account for writes + bitmaps for two files */
nblocks += reiserfs_xattr_nblocks(inode, size) * 4;
posix_acl_release(acl);
}
return nblocks;
}
/*
* Called under i_mutex
*/
int reiserfs_acl_chmod(struct dentry *dentry)
{
struct inode *inode = d_inode(dentry);
if (IS_PRIVATE(inode))
return 0;
if (get_inode_sd_version(inode) == STAT_DATA_V1 ||
!reiserfs_posixacl(inode->i_sb))
return 0;
return posix_acl_chmod(&nop_mnt_idmap, dentry, inode->i_mode);
}