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// SPDX-License-Identifier: GPL-2.0
/*
* linux/drivers/staging/erofs/xattr.c
*
* Copyright (C) 2017-2018 HUAWEI, Inc.
* http://www.huawei.com/
* Created by Gao Xiang <gaoxiang25@huawei.com>
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file COPYING in the main directory of the Linux
* distribution for more details.
*/
#include <linux/security.h>
#include "xattr.h"
struct xattr_iter {
struct super_block *sb;
struct page *page;
void *kaddr;
erofs_blk_t blkaddr;
unsigned ofs;
};
static inline void xattr_iter_end(struct xattr_iter *it, bool atomic)
{
/* only init_inode_xattrs use non-atomic once */
if (unlikely(!atomic))
kunmap(it->page);
else
kunmap_atomic(it->kaddr);
unlock_page(it->page);
put_page(it->page);
}
static void init_inode_xattrs(struct inode *inode)
{
struct xattr_iter it;
unsigned i;
struct erofs_xattr_ibody_header *ih;
struct erofs_sb_info *sbi;
struct erofs_vnode *vi;
bool atomic_map;
if (likely(inode_has_inited_xattr(inode)))
return;
vi = EROFS_V(inode);
BUG_ON(!vi->xattr_isize);
sbi = EROFS_I_SB(inode);
it.blkaddr = erofs_blknr(iloc(sbi, vi->nid) + vi->inode_isize);
it.ofs = erofs_blkoff(iloc(sbi, vi->nid) + vi->inode_isize);
it.page = erofs_get_inline_page(inode, it.blkaddr);
BUG_ON(IS_ERR(it.page));
/* read in shared xattr array (non-atomic, see kmalloc below) */
it.kaddr = kmap(it.page);
atomic_map = false;
ih = (struct erofs_xattr_ibody_header *)(it.kaddr + it.ofs);
vi->xattr_shared_count = ih->h_shared_count;
vi->xattr_shared_xattrs = (unsigned *)kmalloc_array(
vi->xattr_shared_count, sizeof(unsigned),
GFP_KERNEL | __GFP_NOFAIL);
/* let's skip ibody header */
it.ofs += sizeof(struct erofs_xattr_ibody_header);
for (i = 0; i < vi->xattr_shared_count; ++i) {
if (unlikely(it.ofs >= EROFS_BLKSIZ)) {
/* cannot be unaligned */
BUG_ON(it.ofs != EROFS_BLKSIZ);
xattr_iter_end(&it, atomic_map);
it.page = erofs_get_meta_page(inode->i_sb,
++it.blkaddr, S_ISDIR(inode->i_mode));
BUG_ON(IS_ERR(it.page));
it.kaddr = kmap_atomic(it.page);
atomic_map = true;
it.ofs = 0;
}
vi->xattr_shared_xattrs[i] =
le32_to_cpu(*(__le32 *)(it.kaddr + it.ofs));
it.ofs += sizeof(__le32);
}
xattr_iter_end(&it, atomic_map);
inode_set_inited_xattr(inode);
}
struct xattr_iter_handlers {
int (*entry)(struct xattr_iter *, struct erofs_xattr_entry *);
int (*name)(struct xattr_iter *, unsigned, char *, unsigned);
int (*alloc_buffer)(struct xattr_iter *, unsigned);
void (*value)(struct xattr_iter *, unsigned, char *, unsigned);
};
static void xattr_iter_fixup(struct xattr_iter *it)
{
if (unlikely(it->ofs >= EROFS_BLKSIZ)) {
xattr_iter_end(it, true);
it->blkaddr += erofs_blknr(it->ofs);
it->page = erofs_get_meta_page(it->sb, it->blkaddr, false);
BUG_ON(IS_ERR(it->page));
it->kaddr = kmap_atomic(it->page);
it->ofs = erofs_blkoff(it->ofs);
}
}
static int inline_xattr_iter_begin(struct xattr_iter *it,
struct inode *inode)
{
struct erofs_vnode *const vi = EROFS_V(inode);
struct erofs_sb_info *const sbi = EROFS_SB(inode->i_sb);
unsigned xattr_header_sz, inline_xattr_ofs;
xattr_header_sz = inlinexattr_header_size(inode);
if (unlikely(xattr_header_sz >= vi->xattr_isize)) {
BUG_ON(xattr_header_sz > vi->xattr_isize);
return -ENOATTR;
}
inline_xattr_ofs = vi->inode_isize + xattr_header_sz;
it->blkaddr = erofs_blknr(iloc(sbi, vi->nid) + inline_xattr_ofs);
it->ofs = erofs_blkoff(iloc(sbi, vi->nid) + inline_xattr_ofs);
it->page = erofs_get_inline_page(inode, it->blkaddr);
BUG_ON(IS_ERR(it->page));
it->kaddr = kmap_atomic(it->page);
return vi->xattr_isize - xattr_header_sz;
}
static int xattr_foreach(struct xattr_iter *it,
struct xattr_iter_handlers *op, unsigned *tlimit)
{
struct erofs_xattr_entry entry;
unsigned value_sz, processed, slice;
int err;
/* 0. fixup blkaddr, ofs, ipage */
xattr_iter_fixup(it);
/*
* 1. read xattr entry to the memory,
* since we do EROFS_XATTR_ALIGN
* therefore entry should be in the page
*/
entry = *(struct erofs_xattr_entry *)(it->kaddr + it->ofs);
if (tlimit != NULL) {
unsigned entry_sz = EROFS_XATTR_ENTRY_SIZE(&entry);
BUG_ON(*tlimit < entry_sz);
*tlimit -= entry_sz;
}
it->ofs += sizeof(struct erofs_xattr_entry);
value_sz = le16_to_cpu(entry.e_value_size);
/* handle entry */
err = op->entry(it, &entry);
if (err) {
it->ofs += entry.e_name_len + value_sz;
goto out;
}
/* 2. handle xattr name (ofs will finally be at the end of name) */
processed = 0;
while (processed < entry.e_name_len) {
if (it->ofs >= EROFS_BLKSIZ) {
BUG_ON(it->ofs > EROFS_BLKSIZ);
xattr_iter_fixup(it);
it->ofs = 0;
}
slice = min_t(unsigned, PAGE_SIZE - it->ofs,
entry.e_name_len - processed);
/* handle name */
err = op->name(it, processed, it->kaddr + it->ofs, slice);
if (err) {
it->ofs += entry.e_name_len - processed + value_sz;
goto out;
}
it->ofs += slice;
processed += slice;
}
/* 3. handle xattr value */
processed = 0;
if (op->alloc_buffer != NULL) {
err = op->alloc_buffer(it, value_sz);
if (err) {
it->ofs += value_sz;
goto out;
}
}
while (processed < value_sz) {
if (it->ofs >= EROFS_BLKSIZ) {
BUG_ON(it->ofs > EROFS_BLKSIZ);
xattr_iter_fixup(it);
it->ofs = 0;
}
slice = min_t(unsigned, PAGE_SIZE - it->ofs,
value_sz - processed);
op->value(it, processed, it->kaddr + it->ofs, slice);
it->ofs += slice;
processed += slice;
}
out:
/* we assume that ofs is aligned with 4 bytes */
it->ofs = EROFS_XATTR_ALIGN(it->ofs);
return err;
}
struct getxattr_iter {
struct xattr_iter it;
char *buffer;
int buffer_size, index;
struct qstr name;
};
static int xattr_entrymatch(struct xattr_iter *_it,
struct erofs_xattr_entry *entry)
{
struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
return (it->index != entry->e_name_index ||
it->name.len != entry->e_name_len) ? -ENOATTR : 0;
}
static int xattr_namematch(struct xattr_iter *_it,
unsigned processed, char *buf, unsigned len)
{
struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
return memcmp(buf, it->name.name + processed, len) ? -ENOATTR : 0;
}
static int xattr_checkbuffer(struct xattr_iter *_it,
unsigned value_sz)
{
struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
int err = it->buffer_size < value_sz ? -ERANGE : 0;
it->buffer_size = value_sz;
return it->buffer == NULL ? 1 : err;
}
static void xattr_copyvalue(struct xattr_iter *_it,
unsigned processed, char *buf, unsigned len)
{
struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
memcpy(it->buffer + processed, buf, len);
}
static struct xattr_iter_handlers find_xattr_handlers = {
.entry = xattr_entrymatch,
.name = xattr_namematch,
.alloc_buffer = xattr_checkbuffer,
.value = xattr_copyvalue
};
static int inline_getxattr(struct inode *inode, struct getxattr_iter *it)
{
int ret;
unsigned remaining;
ret = inline_xattr_iter_begin(&it->it, inode);
if (ret < 0)
return ret;
remaining = ret;
while (remaining) {
ret = xattr_foreach(&it->it, &find_xattr_handlers, &remaining);
if (ret >= 0)
break;
}
xattr_iter_end(&it->it, true);
return ret < 0 ? ret : it->buffer_size;
}
static int shared_getxattr(struct inode *inode, struct getxattr_iter *it)
{
struct erofs_vnode *const vi = EROFS_V(inode);
struct erofs_sb_info *const sbi = EROFS_SB(inode->i_sb);
unsigned i;
int ret = -ENOATTR;
for (i = 0; i < vi->xattr_shared_count; ++i) {
erofs_blk_t blkaddr =
xattrblock_addr(sbi, vi->xattr_shared_xattrs[i]);
it->it.ofs = xattrblock_offset(sbi, vi->xattr_shared_xattrs[i]);
if (!i || blkaddr != it->it.blkaddr) {
if (i)
xattr_iter_end(&it->it, true);
it->it.page = erofs_get_meta_page(inode->i_sb,
blkaddr, false);
BUG_ON(IS_ERR(it->it.page));
it->it.kaddr = kmap_atomic(it->it.page);
it->it.blkaddr = blkaddr;
}
ret = xattr_foreach(&it->it, &find_xattr_handlers, NULL);
if (ret >= 0)
break;
}
if (vi->xattr_shared_count)
xattr_iter_end(&it->it, true);
return ret < 0 ? ret : it->buffer_size;
}
static bool erofs_xattr_user_list(struct dentry *dentry)
{
return test_opt(EROFS_SB(dentry->d_sb), XATTR_USER);
}
static bool erofs_xattr_trusted_list(struct dentry *dentry)
{
return capable(CAP_SYS_ADMIN);
}
int erofs_getxattr(struct inode *inode, int index,
const char *name,
void *buffer, size_t buffer_size)
{
int ret;
struct getxattr_iter it;
if (unlikely(name == NULL))
return -EINVAL;
init_inode_xattrs(inode);
it.index = index;
it.name.len = strlen(name);
if (it.name.len > EROFS_NAME_LEN)
return -ERANGE;
it.name.name = name;
it.buffer = buffer;
it.buffer_size = buffer_size;
it.it.sb = inode->i_sb;
ret = inline_getxattr(inode, &it);
if (ret == -ENOATTR)
ret = shared_getxattr(inode, &it);
return ret;
}
static int erofs_xattr_generic_get(const struct xattr_handler *handler,
struct dentry *unused, struct inode *inode,
const char *name, void *buffer, size_t size)
{
struct erofs_vnode *const vi = EROFS_V(inode);
struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
switch (handler->flags) {
case EROFS_XATTR_INDEX_USER:
if (!test_opt(sbi, XATTR_USER))
return -EOPNOTSUPP;
break;
case EROFS_XATTR_INDEX_TRUSTED:
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
break;
case EROFS_XATTR_INDEX_SECURITY:
break;
default:
return -EINVAL;
}
if (!vi->xattr_isize)
return -ENOATTR;
return erofs_getxattr(inode, handler->flags, name, buffer, size);
}
const struct xattr_handler erofs_xattr_user_handler = {
.prefix = XATTR_USER_PREFIX,
.flags = EROFS_XATTR_INDEX_USER,
.list = erofs_xattr_user_list,
.get = erofs_xattr_generic_get,
};
const struct xattr_handler erofs_xattr_trusted_handler = {
.prefix = XATTR_TRUSTED_PREFIX,
.flags = EROFS_XATTR_INDEX_TRUSTED,
.list = erofs_xattr_trusted_list,
.get = erofs_xattr_generic_get,
};
#ifdef CONFIG_EROFS_FS_SECURITY
const struct xattr_handler __maybe_unused erofs_xattr_security_handler = {
.prefix = XATTR_SECURITY_PREFIX,
.flags = EROFS_XATTR_INDEX_SECURITY,
.get = erofs_xattr_generic_get,
};
#endif
const struct xattr_handler *erofs_xattr_handlers[] = {
&erofs_xattr_user_handler,
#ifdef CONFIG_EROFS_FS_POSIX_ACL
&posix_acl_access_xattr_handler,
&posix_acl_default_xattr_handler,
#endif
&erofs_xattr_trusted_handler,
#ifdef CONFIG_EROFS_FS_SECURITY
&erofs_xattr_security_handler,
#endif
NULL,
};
struct listxattr_iter {
struct xattr_iter it;
struct dentry *dentry;
char *buffer;
int buffer_size, buffer_ofs;
};
static int xattr_entrylist(struct xattr_iter *_it,
struct erofs_xattr_entry *entry)
{
struct listxattr_iter *it =
container_of(_it, struct listxattr_iter, it);
unsigned prefix_len;
const char *prefix;
const struct xattr_handler *h =
erofs_xattr_handler(entry->e_name_index);
if (h == NULL || (h->list != NULL && !h->list(it->dentry)))
return 1;
/* Note that at least one of 'prefix' and 'name' should be non-NULL */
prefix = h->prefix != NULL ? h->prefix : h->name;
prefix_len = strlen(prefix);
if (it->buffer == NULL) {
it->buffer_ofs += prefix_len + entry->e_name_len + 1;
return 1;
}
if (it->buffer_ofs + prefix_len
+ entry->e_name_len + 1 > it->buffer_size)
return -ERANGE;
memcpy(it->buffer + it->buffer_ofs, prefix, prefix_len);
it->buffer_ofs += prefix_len;
return 0;
}
static int xattr_namelist(struct xattr_iter *_it,
unsigned processed, char *buf, unsigned len)
{
struct listxattr_iter *it =
container_of(_it, struct listxattr_iter, it);
memcpy(it->buffer + it->buffer_ofs, buf, len);
it->buffer_ofs += len;
return 0;
}
static int xattr_skipvalue(struct xattr_iter *_it,
unsigned value_sz)
{
struct listxattr_iter *it =
container_of(_it, struct listxattr_iter, it);
it->buffer[it->buffer_ofs++] = '\0';
return 1;
}
static struct xattr_iter_handlers list_xattr_handlers = {
.entry = xattr_entrylist,
.name = xattr_namelist,
.alloc_buffer = xattr_skipvalue,
.value = NULL
};
static int inline_listxattr(struct listxattr_iter *it)
{
int ret;
unsigned remaining;
ret = inline_xattr_iter_begin(&it->it, d_inode(it->dentry));
if (ret < 0)
return ret;
remaining = ret;
while (remaining) {
ret = xattr_foreach(&it->it, &list_xattr_handlers, &remaining);
if (ret < 0)
break;
}
xattr_iter_end(&it->it, true);
return ret < 0 ? ret : it->buffer_ofs;
}
static int shared_listxattr(struct listxattr_iter *it)
{
struct inode *const inode = d_inode(it->dentry);
struct erofs_vnode *const vi = EROFS_V(inode);
struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
unsigned i;
int ret = 0;
for (i = 0; i < vi->xattr_shared_count; ++i) {
erofs_blk_t blkaddr =
xattrblock_addr(sbi, vi->xattr_shared_xattrs[i]);
it->it.ofs = xattrblock_offset(sbi, vi->xattr_shared_xattrs[i]);
if (!i || blkaddr != it->it.blkaddr) {
if (i)
xattr_iter_end(&it->it, true);
it->it.page = erofs_get_meta_page(inode->i_sb,
blkaddr, false);
BUG_ON(IS_ERR(it->it.page));
it->it.kaddr = kmap_atomic(it->it.page);
it->it.blkaddr = blkaddr;
}
ret = xattr_foreach(&it->it, &list_xattr_handlers, NULL);
if (ret < 0)
break;
}
if (vi->xattr_shared_count)
xattr_iter_end(&it->it, true);
return ret < 0 ? ret : it->buffer_ofs;
}
ssize_t erofs_listxattr(struct dentry *dentry,
char *buffer, size_t buffer_size)
{
int ret;
struct listxattr_iter it;
init_inode_xattrs(d_inode(dentry));
it.dentry = dentry;
it.buffer = buffer;
it.buffer_size = buffer_size;
it.buffer_ofs = 0;
it.it.sb = dentry->d_sb;
ret = inline_listxattr(&it);
if (ret < 0 && ret != -ENOATTR)
return ret;
return shared_listxattr(&it);
}