xattr_trusted.c

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/*
 * linux/fs/ext4/xattr_trusted.c
 * Handler for trusted extended attributes.
 *
 * Copyright (C) 2003 by Andreas Gruenbacher, <[email protected]>
 */

#include <linux/string.h>
#include <linux/capability.h>
#include <linux/fs.h>
#include "ext4_jbd2.h"
#include "ext4.h"
#include "xattr.h"

static size_t
ext4_xattr_trusted_list(struct dentry *dentry, char *list, size_t list_size,
        const char *name, size_t name_len, int type)
{
    const size_t prefix_len = XATTR_TRUSTED_PREFIX_LEN;
    const size_t total_len = prefix_len + name_len + 1;

    if (!capable(CAP_SYS_ADMIN))
        return 0;

    if (list && total_len <= list_size) {
        memcpy(list, XATTR_TRUSTED_PREFIX, prefix_len);
        memcpy(list+prefix_len, name, name_len);
        list[prefix_len + name_len] = '\0';
    }
    return total_len;
}

static int
ext4_xattr_trusted_get(struct dentry *dentry, const char *name, void *buffer,
        size_t size, int type)
{
    if (strcmp(name, "") == 0)
        return -EINVAL;
    return ext4_xattr_get(dentry->d_inode, EXT4_XATTR_INDEX_TRUSTED,
                  name, buffer, size);
}

static int
ext4_xattr_trusted_set(struct dentry *dentry, const char *name,
        const void *value, size_t size, int flags, int type)
{
    if (strcmp(name, "") == 0)
        return -EINVAL;
    return ext4_xattr_set(dentry->d_inode, EXT4_XATTR_INDEX_TRUSTED,
                  name, value, size, flags);
}

const struct xattr_handler ext4_xattr_trusted_handler = {
    .prefix = XATTR_TRUSTED_PREFIX,
    .list   = ext4_xattr_trusted_list,
    .get    = ext4_xattr_trusted_get,
    .set    = ext4_xattr_trusted_set,
};