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