alistair23-linux/fs/f2fs/acl.c
Jaegeuk Kim 8ae8f1627f f2fs: support xattr security labels
This patch adds the support of security labels for f2fs, which will be used
by Linus Security Models (LSMs).

Quote from http://en.wikipedia.org/wiki/Linux_Security_Modules:
"Linux Security Modules (LSM) is a framework that allows the Linux kernel to
support a variety of computer security models while avoiding favoritism toward
any single security implementation. The framework is licensed under the terms of
the GNU General Public License and is standard part of the Linux kernel since
Linux 2.6. AppArmor, SELinux, Smack and TOMOYO Linux are the currently accepted
modules in the official kernel.".

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-06-11 16:01:03 +09:00

413 lines
9.5 KiB
C

/*
* fs/f2fs/acl.c
*
* Copyright (c) 2012 Samsung Electronics Co., Ltd.
* http://www.samsung.com/
*
* Portions of this code from linux/fs/ext2/acl.c
*
* Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/f2fs_fs.h>
#include "f2fs.h"
#include "xattr.h"
#include "acl.h"
#define get_inode_mode(i) ((is_inode_flag_set(F2FS_I(i), FI_ACL_MODE)) ? \
(F2FS_I(i)->i_acl_mode) : ((i)->i_mode))
static inline size_t f2fs_acl_size(int count)
{
if (count <= 4) {
return sizeof(struct f2fs_acl_header) +
count * sizeof(struct f2fs_acl_entry_short);
} else {
return sizeof(struct f2fs_acl_header) +
4 * sizeof(struct f2fs_acl_entry_short) +
(count - 4) * sizeof(struct f2fs_acl_entry);
}
}
static inline int f2fs_acl_count(size_t size)
{
ssize_t s;
size -= sizeof(struct f2fs_acl_header);
s = size - 4 * sizeof(struct f2fs_acl_entry_short);
if (s < 0) {
if (size % sizeof(struct f2fs_acl_entry_short))
return -1;
return size / sizeof(struct f2fs_acl_entry_short);
} else {
if (s % sizeof(struct f2fs_acl_entry))
return -1;
return s / sizeof(struct f2fs_acl_entry) + 4;
}
}
static struct posix_acl *f2fs_acl_from_disk(const char *value, size_t size)
{
int i, count;
struct posix_acl *acl;
struct f2fs_acl_header *hdr = (struct f2fs_acl_header *)value;
struct f2fs_acl_entry *entry = (struct f2fs_acl_entry *)(hdr + 1);
const char *end = value + size;
if (hdr->a_version != cpu_to_le32(F2FS_ACL_VERSION))
return ERR_PTR(-EINVAL);
count = f2fs_acl_count(size);
if (count < 0)
return ERR_PTR(-EINVAL);
if (count == 0)
return NULL;
acl = posix_acl_alloc(count, GFP_KERNEL);
if (!acl)
return ERR_PTR(-ENOMEM);
for (i = 0; i < count; i++) {
if ((char *)entry > end)
goto fail;
acl->a_entries[i].e_tag = le16_to_cpu(entry->e_tag);
acl->a_entries[i].e_perm = le16_to_cpu(entry->e_perm);
switch (acl->a_entries[i].e_tag) {
case ACL_USER_OBJ:
case ACL_GROUP_OBJ:
case ACL_MASK:
case ACL_OTHER:
entry = (struct f2fs_acl_entry *)((char *)entry +
sizeof(struct f2fs_acl_entry_short));
break;
case ACL_USER:
acl->a_entries[i].e_uid =
make_kuid(&init_user_ns,
le32_to_cpu(entry->e_id));
entry = (struct f2fs_acl_entry *)((char *)entry +
sizeof(struct f2fs_acl_entry));
break;
case ACL_GROUP:
acl->a_entries[i].e_gid =
make_kgid(&init_user_ns,
le32_to_cpu(entry->e_id));
entry = (struct f2fs_acl_entry *)((char *)entry +
sizeof(struct f2fs_acl_entry));
break;
default:
goto fail;
}
}
if ((char *)entry != end)
goto fail;
return acl;
fail:
posix_acl_release(acl);
return ERR_PTR(-EINVAL);
}
static void *f2fs_acl_to_disk(const struct posix_acl *acl, size_t *size)
{
struct f2fs_acl_header *f2fs_acl;
struct f2fs_acl_entry *entry;
int i;
f2fs_acl = kmalloc(sizeof(struct f2fs_acl_header) + acl->a_count *
sizeof(struct f2fs_acl_entry), GFP_KERNEL);
if (!f2fs_acl)
return ERR_PTR(-ENOMEM);
f2fs_acl->a_version = cpu_to_le32(F2FS_ACL_VERSION);
entry = (struct f2fs_acl_entry *)(f2fs_acl + 1);
for (i = 0; i < acl->a_count; i++) {
entry->e_tag = cpu_to_le16(acl->a_entries[i].e_tag);
entry->e_perm = cpu_to_le16(acl->a_entries[i].e_perm);
switch (acl->a_entries[i].e_tag) {
case ACL_USER:
entry->e_id = cpu_to_le32(
from_kuid(&init_user_ns,
acl->a_entries[i].e_uid));
entry = (struct f2fs_acl_entry *)((char *)entry +
sizeof(struct f2fs_acl_entry));
break;
case ACL_GROUP:
entry->e_id = cpu_to_le32(
from_kgid(&init_user_ns,
acl->a_entries[i].e_gid));
entry = (struct f2fs_acl_entry *)((char *)entry +
sizeof(struct f2fs_acl_entry));
break;
case ACL_USER_OBJ:
case ACL_GROUP_OBJ:
case ACL_MASK:
case ACL_OTHER:
entry = (struct f2fs_acl_entry *)((char *)entry +
sizeof(struct f2fs_acl_entry_short));
break;
default:
goto fail;
}
}
*size = f2fs_acl_size(acl->a_count);
return (void *)f2fs_acl;
fail:
kfree(f2fs_acl);
return ERR_PTR(-EINVAL);
}
struct posix_acl *f2fs_get_acl(struct inode *inode, int type)
{
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
int name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
void *value = NULL;
struct posix_acl *acl;
int retval;
if (!test_opt(sbi, POSIX_ACL))
return NULL;
acl = get_cached_acl(inode, type);
if (acl != ACL_NOT_CACHED)
return acl;
if (type == ACL_TYPE_ACCESS)
name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
retval = f2fs_getxattr(inode, name_index, "", NULL, 0);
if (retval > 0) {
value = kmalloc(retval, GFP_KERNEL);
if (!value)
return ERR_PTR(-ENOMEM);
retval = f2fs_getxattr(inode, name_index, "", value, retval);
}
if (retval > 0)
acl = f2fs_acl_from_disk(value, retval);
else if (retval == -ENODATA)
acl = NULL;
else
acl = ERR_PTR(retval);
kfree(value);
if (!IS_ERR(acl))
set_cached_acl(inode, type, acl);
return acl;
}
static int f2fs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
{
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
struct f2fs_inode_info *fi = F2FS_I(inode);
int name_index;
void *value = NULL;
size_t size = 0;
int error;
if (!test_opt(sbi, POSIX_ACL))
return 0;
if (S_ISLNK(inode->i_mode))
return -EOPNOTSUPP;
switch (type) {
case ACL_TYPE_ACCESS:
name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
if (acl) {
error = posix_acl_equiv_mode(acl, &inode->i_mode);
if (error < 0)
return error;
set_acl_inode(fi, inode->i_mode);
if (error == 0)
acl = NULL;
}
break;
case ACL_TYPE_DEFAULT:
name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
if (!S_ISDIR(inode->i_mode))
return acl ? -EACCES : 0;
break;
default:
return -EINVAL;
}
if (acl) {
value = f2fs_acl_to_disk(acl, &size);
if (IS_ERR(value)) {
cond_clear_inode_flag(fi, FI_ACL_MODE);
return (int)PTR_ERR(value);
}
}
error = f2fs_setxattr(inode, name_index, "", value, size, NULL);
kfree(value);
if (!error)
set_cached_acl(inode, type, acl);
cond_clear_inode_flag(fi, FI_ACL_MODE);
return error;
}
int f2fs_init_acl(struct inode *inode, struct inode *dir)
{
struct posix_acl *acl = NULL;
struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
int error = 0;
if (!S_ISLNK(inode->i_mode)) {
if (test_opt(sbi, POSIX_ACL)) {
acl = f2fs_get_acl(dir, ACL_TYPE_DEFAULT);
if (IS_ERR(acl))
return PTR_ERR(acl);
}
if (!acl)
inode->i_mode &= ~current_umask();
}
if (test_opt(sbi, POSIX_ACL) && acl) {
if (S_ISDIR(inode->i_mode)) {
error = f2fs_set_acl(inode, ACL_TYPE_DEFAULT, acl);
if (error)
goto cleanup;
}
error = posix_acl_create(&acl, GFP_KERNEL, &inode->i_mode);
if (error < 0)
return error;
if (error > 0)
error = f2fs_set_acl(inode, ACL_TYPE_ACCESS, acl);
}
cleanup:
posix_acl_release(acl);
return error;
}
int f2fs_acl_chmod(struct inode *inode)
{
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
struct posix_acl *acl;
int error;
umode_t mode = get_inode_mode(inode);
if (!test_opt(sbi, POSIX_ACL))
return 0;
if (S_ISLNK(mode))
return -EOPNOTSUPP;
acl = f2fs_get_acl(inode, ACL_TYPE_ACCESS);
if (IS_ERR(acl) || !acl)
return PTR_ERR(acl);
error = posix_acl_chmod(&acl, GFP_KERNEL, mode);
if (error)
return error;
error = f2fs_set_acl(inode, ACL_TYPE_ACCESS, acl);
posix_acl_release(acl);
return error;
}
static size_t f2fs_xattr_list_acl(struct dentry *dentry, char *list,
size_t list_size, const char *name, size_t name_len, int type)
{
struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
const char *xname = POSIX_ACL_XATTR_DEFAULT;
size_t size;
if (!test_opt(sbi, POSIX_ACL))
return 0;
if (type == ACL_TYPE_ACCESS)
xname = POSIX_ACL_XATTR_ACCESS;
size = strlen(xname) + 1;
if (list && size <= list_size)
memcpy(list, xname, size);
return size;
}
static int f2fs_xattr_get_acl(struct dentry *dentry, const char *name,
void *buffer, size_t size, int type)
{
struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
struct posix_acl *acl;
int error;
if (strcmp(name, "") != 0)
return -EINVAL;
if (!test_opt(sbi, POSIX_ACL))
return -EOPNOTSUPP;
acl = f2fs_get_acl(dentry->d_inode, type);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (!acl)
return -ENODATA;
error = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
posix_acl_release(acl);
return error;
}
static int f2fs_xattr_set_acl(struct dentry *dentry, const char *name,
const void *value, size_t size, int flags, int type)
{
struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
struct inode *inode = dentry->d_inode;
struct posix_acl *acl = NULL;
int error;
if (strcmp(name, "") != 0)
return -EINVAL;
if (!test_opt(sbi, POSIX_ACL))
return -EOPNOTSUPP;
if (!inode_owner_or_capable(inode))
return -EPERM;
if (value) {
acl = posix_acl_from_xattr(&init_user_ns, value, size);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (acl) {
error = posix_acl_valid(acl);
if (error)
goto release_and_out;
}
} else {
acl = NULL;
}
error = f2fs_set_acl(inode, type, acl);
release_and_out:
posix_acl_release(acl);
return error;
}
const struct xattr_handler f2fs_xattr_acl_default_handler = {
.prefix = POSIX_ACL_XATTR_DEFAULT,
.flags = ACL_TYPE_DEFAULT,
.list = f2fs_xattr_list_acl,
.get = f2fs_xattr_get_acl,
.set = f2fs_xattr_set_acl,
};
const struct xattr_handler f2fs_xattr_acl_access_handler = {
.prefix = POSIX_ACL_XATTR_ACCESS,
.flags = ACL_TYPE_ACCESS,
.list = f2fs_xattr_list_acl,
.get = f2fs_xattr_get_acl,
.set = f2fs_xattr_set_acl,
};