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![Phillip Lougher](/assets/img/avatar_default.png)
My existing email address may stop working in a month or two, so update email to one that will continue working. Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
324 lines
8.4 KiB
C
324 lines
8.4 KiB
C
/*
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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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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2,
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* or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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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->d_inode;
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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, prefix_size = 0;
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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)
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prefix_size = handler->list(d, buffer, rest, NULL,
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name_size, handler->flags);
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if (prefix_size) {
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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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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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/*
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* User namespace support
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*/
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static size_t squashfs_user_list(struct dentry *d, char *list, size_t list_size,
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const char *name, size_t name_len, int type)
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{
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if (list && XATTR_USER_PREFIX_LEN <= list_size)
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memcpy(list, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
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return XATTR_USER_PREFIX_LEN;
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}
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static int squashfs_user_get(struct dentry *d, const char *name, void *buffer,
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size_t size, int type)
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{
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if (name[0] == '\0')
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return -EINVAL;
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return squashfs_xattr_get(d->d_inode, SQUASHFS_XATTR_USER, name,
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buffer, size);
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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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.list = squashfs_user_list,
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.get = squashfs_user_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 size_t squashfs_trusted_list(struct dentry *d, char *list,
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size_t list_size, const char *name, size_t name_len, int type)
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{
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if (!capable(CAP_SYS_ADMIN))
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return 0;
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if (list && XATTR_TRUSTED_PREFIX_LEN <= list_size)
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memcpy(list, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN);
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return XATTR_TRUSTED_PREFIX_LEN;
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}
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static int squashfs_trusted_get(struct dentry *d, const char *name,
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void *buffer, size_t size, int type)
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{
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if (name[0] == '\0')
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return -EINVAL;
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return squashfs_xattr_get(d->d_inode, SQUASHFS_XATTR_TRUSTED, name,
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buffer, size);
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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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.list = squashfs_trusted_list,
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.get = squashfs_trusted_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 size_t squashfs_security_list(struct dentry *d, char *list,
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size_t list_size, const char *name, size_t name_len, int type)
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{
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if (list && XATTR_SECURITY_PREFIX_LEN <= list_size)
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memcpy(list, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN);
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return XATTR_SECURITY_PREFIX_LEN;
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}
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static int squashfs_security_get(struct dentry *d, const char *name,
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void *buffer, size_t size, int type)
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{
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if (name[0] == '\0')
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return -EINVAL;
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return squashfs_xattr_get(d->d_inode, SQUASHFS_XATTR_SECURITY, name,
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buffer, size);
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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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.list = squashfs_security_list,
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.get = squashfs_security_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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