linux-stable/fs/f2fs/xattr.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

501 lines
12 KiB
C

/*
* fs/f2fs/xattr.c
*
* Copyright (c) 2012 Samsung Electronics Co., Ltd.
* http://www.samsung.com/
*
* Portions of this code from linux/fs/ext2/xattr.c
*
* Copyright (C) 2001-2003 Andreas Gruenbacher <agruen@suse.de>
*
* Fix by Harrison Xing <harrison@mountainviewdata.com>.
* Extended attributes for symlinks and special files added per
* suggestion of Luka Renko <luka.renko@hermes.si>.
* xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
* Red Hat Inc.
*
* 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/rwsem.h>
#include <linux/f2fs_fs.h>
#include <linux/security.h>
#include "f2fs.h"
#include "xattr.h"
static size_t f2fs_xattr_generic_list(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);
int total_len, prefix_len = 0;
const char *prefix = NULL;
switch (type) {
case F2FS_XATTR_INDEX_USER:
if (!test_opt(sbi, XATTR_USER))
return -EOPNOTSUPP;
prefix = XATTR_USER_PREFIX;
prefix_len = XATTR_USER_PREFIX_LEN;
break;
case F2FS_XATTR_INDEX_TRUSTED:
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
prefix = XATTR_TRUSTED_PREFIX;
prefix_len = XATTR_TRUSTED_PREFIX_LEN;
break;
case F2FS_XATTR_INDEX_SECURITY:
prefix = XATTR_SECURITY_PREFIX;
prefix_len = XATTR_SECURITY_PREFIX_LEN;
break;
default:
return -EINVAL;
}
total_len = prefix_len + name_len + 1;
if (list && total_len <= list_size) {
memcpy(list, prefix, prefix_len);
memcpy(list + prefix_len, name, name_len);
list[prefix_len + name_len] = '\0';
}
return total_len;
}
static int f2fs_xattr_generic_get(struct dentry *dentry, const char *name,
void *buffer, size_t size, int type)
{
struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
switch (type) {
case F2FS_XATTR_INDEX_USER:
if (!test_opt(sbi, XATTR_USER))
return -EOPNOTSUPP;
break;
case F2FS_XATTR_INDEX_TRUSTED:
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
break;
case F2FS_XATTR_INDEX_SECURITY:
break;
default:
return -EINVAL;
}
if (strcmp(name, "") == 0)
return -EINVAL;
return f2fs_getxattr(dentry->d_inode, type, name, buffer, size);
}
static int f2fs_xattr_generic_set(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);
switch (type) {
case F2FS_XATTR_INDEX_USER:
if (!test_opt(sbi, XATTR_USER))
return -EOPNOTSUPP;
break;
case F2FS_XATTR_INDEX_TRUSTED:
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
break;
case F2FS_XATTR_INDEX_SECURITY:
break;
default:
return -EINVAL;
}
if (strcmp(name, "") == 0)
return -EINVAL;
return f2fs_setxattr(dentry->d_inode, type, name, value, size, NULL);
}
static size_t f2fs_xattr_advise_list(struct dentry *dentry, char *list,
size_t list_size, const char *name, size_t name_len, int type)
{
const char *xname = F2FS_SYSTEM_ADVISE_PREFIX;
size_t size;
if (type != F2FS_XATTR_INDEX_ADVISE)
return 0;
size = strlen(xname) + 1;
if (list && size <= list_size)
memcpy(list, xname, size);
return size;
}
static int f2fs_xattr_advise_get(struct dentry *dentry, const char *name,
void *buffer, size_t size, int type)
{
struct inode *inode = dentry->d_inode;
if (strcmp(name, "") != 0)
return -EINVAL;
*((char *)buffer) = F2FS_I(inode)->i_advise;
return sizeof(char);
}
static int f2fs_xattr_advise_set(struct dentry *dentry, const char *name,
const void *value, size_t size, int flags, int type)
{
struct inode *inode = dentry->d_inode;
if (strcmp(name, "") != 0)
return -EINVAL;
if (!inode_owner_or_capable(inode))
return -EPERM;
if (value == NULL)
return -EINVAL;
F2FS_I(inode)->i_advise |= *(char *)value;
return 0;
}
#ifdef CONFIG_F2FS_FS_SECURITY
static int f2fs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
void *page)
{
const struct xattr *xattr;
int err = 0;
for (xattr = xattr_array; xattr->name != NULL; xattr++) {
err = f2fs_setxattr(inode, F2FS_XATTR_INDEX_SECURITY,
xattr->name, xattr->value,
xattr->value_len, (struct page *)page);
if (err < 0)
break;
}
return err;
}
int f2fs_init_security(struct inode *inode, struct inode *dir,
const struct qstr *qstr, struct page *ipage)
{
return security_inode_init_security(inode, dir, qstr,
&f2fs_initxattrs, ipage);
}
#endif
const struct xattr_handler f2fs_xattr_user_handler = {
.prefix = XATTR_USER_PREFIX,
.flags = F2FS_XATTR_INDEX_USER,
.list = f2fs_xattr_generic_list,
.get = f2fs_xattr_generic_get,
.set = f2fs_xattr_generic_set,
};
const struct xattr_handler f2fs_xattr_trusted_handler = {
.prefix = XATTR_TRUSTED_PREFIX,
.flags = F2FS_XATTR_INDEX_TRUSTED,
.list = f2fs_xattr_generic_list,
.get = f2fs_xattr_generic_get,
.set = f2fs_xattr_generic_set,
};
const struct xattr_handler f2fs_xattr_advise_handler = {
.prefix = F2FS_SYSTEM_ADVISE_PREFIX,
.flags = F2FS_XATTR_INDEX_ADVISE,
.list = f2fs_xattr_advise_list,
.get = f2fs_xattr_advise_get,
.set = f2fs_xattr_advise_set,
};
const struct xattr_handler f2fs_xattr_security_handler = {
.prefix = XATTR_SECURITY_PREFIX,
.flags = F2FS_XATTR_INDEX_SECURITY,
.list = f2fs_xattr_generic_list,
.get = f2fs_xattr_generic_get,
.set = f2fs_xattr_generic_set,
};
static const struct xattr_handler *f2fs_xattr_handler_map[] = {
[F2FS_XATTR_INDEX_USER] = &f2fs_xattr_user_handler,
#ifdef CONFIG_F2FS_FS_POSIX_ACL
[F2FS_XATTR_INDEX_POSIX_ACL_ACCESS] = &f2fs_xattr_acl_access_handler,
[F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT] = &f2fs_xattr_acl_default_handler,
#endif
[F2FS_XATTR_INDEX_TRUSTED] = &f2fs_xattr_trusted_handler,
#ifdef CONFIG_F2FS_FS_SECURITY
[F2FS_XATTR_INDEX_SECURITY] = &f2fs_xattr_security_handler,
#endif
[F2FS_XATTR_INDEX_ADVISE] = &f2fs_xattr_advise_handler,
};
const struct xattr_handler *f2fs_xattr_handlers[] = {
&f2fs_xattr_user_handler,
#ifdef CONFIG_F2FS_FS_POSIX_ACL
&f2fs_xattr_acl_access_handler,
&f2fs_xattr_acl_default_handler,
#endif
&f2fs_xattr_trusted_handler,
#ifdef CONFIG_F2FS_FS_SECURITY
&f2fs_xattr_security_handler,
#endif
&f2fs_xattr_advise_handler,
NULL,
};
static inline const struct xattr_handler *f2fs_xattr_handler(int name_index)
{
const struct xattr_handler *handler = NULL;
if (name_index > 0 && name_index < ARRAY_SIZE(f2fs_xattr_handler_map))
handler = f2fs_xattr_handler_map[name_index];
return handler;
}
int f2fs_getxattr(struct inode *inode, int name_index, const char *name,
void *buffer, size_t buffer_size)
{
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
struct f2fs_inode_info *fi = F2FS_I(inode);
struct f2fs_xattr_entry *entry;
struct page *page;
void *base_addr;
int error = 0, found = 0;
size_t value_len, name_len;
if (name == NULL)
return -EINVAL;
name_len = strlen(name);
if (!fi->i_xattr_nid)
return -ENODATA;
page = get_node_page(sbi, fi->i_xattr_nid);
if (IS_ERR(page))
return PTR_ERR(page);
base_addr = page_address(page);
list_for_each_xattr(entry, base_addr) {
if (entry->e_name_index != name_index)
continue;
if (entry->e_name_len != name_len)
continue;
if (!memcmp(entry->e_name, name, name_len)) {
found = 1;
break;
}
}
if (!found) {
error = -ENODATA;
goto cleanup;
}
value_len = le16_to_cpu(entry->e_value_size);
if (buffer && value_len > buffer_size) {
error = -ERANGE;
goto cleanup;
}
if (buffer) {
char *pval = entry->e_name + entry->e_name_len;
memcpy(buffer, pval, value_len);
}
error = value_len;
cleanup:
f2fs_put_page(page, 1);
return error;
}
ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
{
struct inode *inode = dentry->d_inode;
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
struct f2fs_inode_info *fi = F2FS_I(inode);
struct f2fs_xattr_entry *entry;
struct page *page;
void *base_addr;
int error = 0;
size_t rest = buffer_size;
if (!fi->i_xattr_nid)
return 0;
page = get_node_page(sbi, fi->i_xattr_nid);
if (IS_ERR(page))
return PTR_ERR(page);
base_addr = page_address(page);
list_for_each_xattr(entry, base_addr) {
const struct xattr_handler *handler =
f2fs_xattr_handler(entry->e_name_index);
size_t size;
if (!handler)
continue;
size = handler->list(dentry, buffer, rest, entry->e_name,
entry->e_name_len, handler->flags);
if (buffer && size > rest) {
error = -ERANGE;
goto cleanup;
}
if (buffer)
buffer += size;
rest -= size;
}
error = buffer_size - rest;
cleanup:
f2fs_put_page(page, 1);
return error;
}
int f2fs_setxattr(struct inode *inode, int name_index, const char *name,
const void *value, size_t value_len, struct page *ipage)
{
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
struct f2fs_inode_info *fi = F2FS_I(inode);
struct f2fs_xattr_header *header = NULL;
struct f2fs_xattr_entry *here, *last;
struct page *page;
void *base_addr;
int error, found, free, newsize;
size_t name_len;
char *pval;
int ilock;
if (name == NULL)
return -EINVAL;
if (value == NULL)
value_len = 0;
name_len = strlen(name);
if (name_len > F2FS_NAME_LEN || value_len > MAX_VALUE_LEN)
return -ERANGE;
f2fs_balance_fs(sbi);
ilock = mutex_lock_op(sbi);
if (!fi->i_xattr_nid) {
/* Allocate new attribute block */
struct dnode_of_data dn;
if (!alloc_nid(sbi, &fi->i_xattr_nid)) {
error = -ENOSPC;
goto exit;
}
set_new_dnode(&dn, inode, NULL, NULL, fi->i_xattr_nid);
mark_inode_dirty(inode);
page = new_node_page(&dn, XATTR_NODE_OFFSET, ipage);
if (IS_ERR(page)) {
alloc_nid_failed(sbi, fi->i_xattr_nid);
fi->i_xattr_nid = 0;
error = PTR_ERR(page);
goto exit;
}
alloc_nid_done(sbi, fi->i_xattr_nid);
base_addr = page_address(page);
header = XATTR_HDR(base_addr);
header->h_magic = cpu_to_le32(F2FS_XATTR_MAGIC);
header->h_refcount = cpu_to_le32(1);
} else {
/* The inode already has an extended attribute block. */
page = get_node_page(sbi, fi->i_xattr_nid);
if (IS_ERR(page)) {
error = PTR_ERR(page);
goto exit;
}
base_addr = page_address(page);
header = XATTR_HDR(base_addr);
}
if (le32_to_cpu(header->h_magic) != F2FS_XATTR_MAGIC) {
error = -EIO;
goto cleanup;
}
/* find entry with wanted name. */
found = 0;
list_for_each_xattr(here, base_addr) {
if (here->e_name_index != name_index)
continue;
if (here->e_name_len != name_len)
continue;
if (!memcmp(here->e_name, name, name_len)) {
found = 1;
break;
}
}
last = here;
while (!IS_XATTR_LAST_ENTRY(last))
last = XATTR_NEXT_ENTRY(last);
newsize = XATTR_ALIGN(sizeof(struct f2fs_xattr_entry) +
name_len + value_len);
/* 1. Check space */
if (value) {
/* If value is NULL, it is remove operation.
* In case of update operation, we caculate free.
*/
free = MIN_OFFSET - ((char *)last - (char *)header);
if (found)
free = free - ENTRY_SIZE(here);
if (free < newsize) {
error = -ENOSPC;
goto cleanup;
}
}
/* 2. Remove old entry */
if (found) {
/* If entry is found, remove old entry.
* If not found, remove operation is not needed.
*/
struct f2fs_xattr_entry *next = XATTR_NEXT_ENTRY(here);
int oldsize = ENTRY_SIZE(here);
memmove(here, next, (char *)last - (char *)next);
last = (struct f2fs_xattr_entry *)((char *)last - oldsize);
memset(last, 0, oldsize);
}
/* 3. Write new entry */
if (value) {
/* Before we come here, old entry is removed.
* We just write new entry. */
memset(last, 0, newsize);
last->e_name_index = name_index;
last->e_name_len = name_len;
memcpy(last->e_name, name, name_len);
pval = last->e_name + name_len;
memcpy(pval, value, value_len);
last->e_value_size = cpu_to_le16(value_len);
}
set_page_dirty(page);
f2fs_put_page(page, 1);
if (is_inode_flag_set(fi, FI_ACL_MODE)) {
inode->i_mode = fi->i_acl_mode;
inode->i_ctime = CURRENT_TIME;
clear_inode_flag(fi, FI_ACL_MODE);
}
if (ipage)
update_inode(inode, ipage);
else
update_inode_page(inode);
mutex_unlock_op(sbi, ilock);
return 0;
cleanup:
f2fs_put_page(page, 1);
exit:
mutex_unlock_op(sbi, ilock);
return error;
}