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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Squashfs - a compressed read only filesystem for Linux
*
* Copyright (c) 2010
* Phillip Lougher <phillip@squashfs.org.uk>
*
* xattr.c
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/fs.h>
#include <linux/vfs.h>
#include <linux/xattr.h>
#include <linux/slab.h>
#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "squashfs_fs_i.h"
#include "squashfs.h"
static const struct xattr_handler *squashfs_xattr_handler(int);
ssize_t squashfs_listxattr(struct dentry *d, char *buffer,
size_t buffer_size)
{
struct inode *inode = d_inode(d);
struct super_block *sb = inode->i_sb;
struct squashfs_sb_info *msblk = sb->s_fs_info;
u64 start = SQUASHFS_XATTR_BLK(squashfs_i(inode)->xattr)
+ msblk->xattr_table;
int offset = SQUASHFS_XATTR_OFFSET(squashfs_i(inode)->xattr);
int count = squashfs_i(inode)->xattr_count;
size_t rest = buffer_size;
int err;
/* check that the file system has xattrs */
if (msblk->xattr_id_table == NULL)
return -EOPNOTSUPP;
/* loop reading each xattr name */
while (count--) {
struct squashfs_xattr_entry entry;
struct squashfs_xattr_val val;
const struct xattr_handler *handler;
int name_size;
err = squashfs_read_metadata(sb, &entry, &start, &offset,
sizeof(entry));
if (err < 0)
goto failed;
name_size = le16_to_cpu(entry.size);
handler = squashfs_xattr_handler(le16_to_cpu(entry.type));
if (handler && (!handler->list || handler->list(d))) {
const char *prefix = handler->prefix ?: handler->name;
size_t prefix_size = strlen(prefix);
if (buffer) {
if (prefix_size + name_size + 1 > rest) {
err = -ERANGE;
goto failed;
}
memcpy(buffer, prefix, prefix_size);
buffer += prefix_size;
}
err = squashfs_read_metadata(sb, buffer, &start,
&offset, name_size);
if (err < 0)
goto failed;
if (buffer) {
buffer[name_size] = '\0';
buffer += name_size + 1;
}
rest -= prefix_size + name_size + 1;
} else {
/* no handler or insuffficient privileges, so skip */
err = squashfs_read_metadata(sb, NULL, &start,
&offset, name_size);
if (err < 0)
goto failed;
}
/* skip remaining xattr entry */
err = squashfs_read_metadata(sb, &val, &start, &offset,
sizeof(val));
if (err < 0)
goto failed;
err = squashfs_read_metadata(sb, NULL, &start, &offset,
le32_to_cpu(val.vsize));
if (err < 0)
goto failed;
}
err = buffer_size - rest;
failed:
return err;
}
static int squashfs_xattr_get(struct inode *inode, int name_index,
const char *name, void *buffer, size_t buffer_size)
{
struct super_block *sb = inode->i_sb;
struct squashfs_sb_info *msblk = sb->s_fs_info;
u64 start = SQUASHFS_XATTR_BLK(squashfs_i(inode)->xattr)
+ msblk->xattr_table;
int offset = SQUASHFS_XATTR_OFFSET(squashfs_i(inode)->xattr);
int count = squashfs_i(inode)->xattr_count;
int name_len = strlen(name);
int err, vsize;
char *target = kmalloc(name_len, GFP_KERNEL);
if (target == NULL)
return -ENOMEM;
/* loop reading each xattr name */
for (; count; count--) {
struct squashfs_xattr_entry entry;
struct squashfs_xattr_val val;
int type, prefix, name_size;
err = squashfs_read_metadata(sb, &entry, &start, &offset,
sizeof(entry));
if (err < 0)
goto failed;
name_size = le16_to_cpu(entry.size);
type = le16_to_cpu(entry.type);
prefix = type & SQUASHFS_XATTR_PREFIX_MASK;
if (prefix == name_index && name_size == name_len)
err = squashfs_read_metadata(sb, target, &start,
&offset, name_size);
else
err = squashfs_read_metadata(sb, NULL, &start,
&offset, name_size);
if (err < 0)
goto failed;
if (prefix == name_index && name_size == name_len &&
strncmp(target, name, name_size) == 0) {
/* found xattr */
if (type & SQUASHFS_XATTR_VALUE_OOL) {
__le64 xattr_val;
u64 xattr;
/* val is a reference to the real location */
err = squashfs_read_metadata(sb, &val, &start,
&offset, sizeof(val));
if (err < 0)
goto failed;
err = squashfs_read_metadata(sb, &xattr_val,
&start, &offset, sizeof(xattr_val));
if (err < 0)
goto failed;
xattr = le64_to_cpu(xattr_val);
start = SQUASHFS_XATTR_BLK(xattr) +
msblk->xattr_table;
offset = SQUASHFS_XATTR_OFFSET(xattr);
}
/* read xattr value */
err = squashfs_read_metadata(sb, &val, &start, &offset,
sizeof(val));
if (err < 0)
goto failed;
vsize = le32_to_cpu(val.vsize);
if (buffer) {
if (vsize > buffer_size) {
err = -ERANGE;
goto failed;
}
err = squashfs_read_metadata(sb, buffer, &start,
&offset, vsize);
if (err < 0)
goto failed;
}
break;
}
/* no match, skip remaining xattr entry */
err = squashfs_read_metadata(sb, &val, &start, &offset,
sizeof(val));
if (err < 0)
goto failed;
err = squashfs_read_metadata(sb, NULL, &start, &offset,
le32_to_cpu(val.vsize));
if (err < 0)
goto failed;
}
err = count ? vsize : -ENODATA;
failed:
kfree(target);
return err;
}
static int squashfs_xattr_handler_get(const struct xattr_handler *handler,
struct dentry *unused,
struct inode *inode,
const char *name,
void *buffer, size_t size)
{
return squashfs_xattr_get(inode, handler->flags, name,
buffer, size);
}
/*
* User namespace support
*/
static const struct xattr_handler squashfs_xattr_user_handler = {
.prefix = XATTR_USER_PREFIX,
.flags = SQUASHFS_XATTR_USER,
.get = squashfs_xattr_handler_get
};
/*
* Trusted namespace support
*/
static bool squashfs_trusted_xattr_handler_list(struct dentry *d)
{
return capable(CAP_SYS_ADMIN);
}
static const struct xattr_handler squashfs_xattr_trusted_handler = {
.prefix = XATTR_TRUSTED_PREFIX,
.flags = SQUASHFS_XATTR_TRUSTED,
.list = squashfs_trusted_xattr_handler_list,
.get = squashfs_xattr_handler_get
};
/*
* Security namespace support
*/
static const struct xattr_handler squashfs_xattr_security_handler = {
.prefix = XATTR_SECURITY_PREFIX,
.flags = SQUASHFS_XATTR_SECURITY,
.get = squashfs_xattr_handler_get
};
static const struct xattr_handler *squashfs_xattr_handler(int type)
{
if (type & ~(SQUASHFS_XATTR_PREFIX_MASK | SQUASHFS_XATTR_VALUE_OOL))
/* ignore unrecognised type */
return NULL;
switch (type & SQUASHFS_XATTR_PREFIX_MASK) {
case SQUASHFS_XATTR_USER:
return &squashfs_xattr_user_handler;
case SQUASHFS_XATTR_TRUSTED:
return &squashfs_xattr_trusted_handler;
case SQUASHFS_XATTR_SECURITY:
return &squashfs_xattr_security_handler;
default:
/* ignore unrecognised type */
return NULL;
}
}
const struct xattr_handler * const squashfs_xattr_handlers[] = {
&squashfs_xattr_user_handler,
&squashfs_xattr_trusted_handler,
&squashfs_xattr_security_handler,
NULL
};
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