linux-stable/fs/9p/xattr_security.c
Jim Garlick d9a738597f fs/9p: xattr: add trusted and security namespaces
Allow requests for security.* and trusted.* xattr name spaces
to pass through to server.

The new files are 99% cut and paste from fs/9p/xattr_user.c with the
namespaces changed.  It has the intended effect in superficial testing.
I do not know much detail about how these namespaces are used, but passing
them through to the server, which can decide whether to handle them or not,
seems reasonable.

I want to support a use case where an ext4 file system is mounted via 9P,
then re-exported via samba to windows clients in a cluster.  Windows wants
to store xattrs such as security.NTACL.  This works when ext4 directly
backs samba, but not when 9P is inserted.  This use case is documented here:
   http://code.google.com/p/diod/issues/detail?id=95

Signed-off-by: Jim Garlick <garlick@llnl.gov>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
2013-07-07 22:02:18 -05:00

80 lines
2.1 KiB
C

/*
* Copyright IBM Corporation, 2010
* Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of version 2.1 of the GNU Lesser General Public License
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*
*/
#include <linux/module.h>
#include <linux/string.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include "xattr.h"
static int v9fs_xattr_security_get(struct dentry *dentry, const char *name,
void *buffer, size_t size, int type)
{
int retval;
char *full_name;
size_t name_len;
size_t prefix_len = XATTR_SECURITY_PREFIX_LEN;
if (name == NULL)
return -EINVAL;
if (strcmp(name, "") == 0)
return -EINVAL;
name_len = strlen(name);
full_name = kmalloc(prefix_len + name_len + 1 , GFP_KERNEL);
if (!full_name)
return -ENOMEM;
memcpy(full_name, XATTR_SECURITY_PREFIX, prefix_len);
memcpy(full_name+prefix_len, name, name_len);
full_name[prefix_len + name_len] = '\0';
retval = v9fs_xattr_get(dentry, full_name, buffer, size);
kfree(full_name);
return retval;
}
static int v9fs_xattr_security_set(struct dentry *dentry, const char *name,
const void *value, size_t size, int flags, int type)
{
int retval;
char *full_name;
size_t name_len;
size_t prefix_len = XATTR_SECURITY_PREFIX_LEN;
if (name == NULL)
return -EINVAL;
if (strcmp(name, "") == 0)
return -EINVAL;
name_len = strlen(name);
full_name = kmalloc(prefix_len + name_len + 1 , GFP_KERNEL);
if (!full_name)
return -ENOMEM;
memcpy(full_name, XATTR_SECURITY_PREFIX, prefix_len);
memcpy(full_name + prefix_len, name, name_len);
full_name[prefix_len + name_len] = '\0';
retval = v9fs_xattr_set(dentry, full_name, value, size, flags);
kfree(full_name);
return retval;
}
struct xattr_handler v9fs_xattr_security_handler = {
.prefix = XATTR_SECURITY_PREFIX,
.get = v9fs_xattr_security_get,
.set = v9fs_xattr_security_set,
};