mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-21 12:19:08 +07:00
466b77bc95
Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
117 lines
2.7 KiB
C
117 lines
2.7 KiB
C
/* CacheFiles security management
|
|
*
|
|
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
|
|
* Written by David Howells (dhowells@redhat.com)
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public Licence
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the Licence, or (at your option) any later version.
|
|
*/
|
|
|
|
#include <linux/fs.h>
|
|
#include <linux/cred.h>
|
|
#include "internal.h"
|
|
|
|
/*
|
|
* determine the security context within which we access the cache from within
|
|
* the kernel
|
|
*/
|
|
int cachefiles_get_security_ID(struct cachefiles_cache *cache)
|
|
{
|
|
struct cred *new;
|
|
int ret;
|
|
|
|
_enter("{%s}", cache->secctx);
|
|
|
|
new = prepare_kernel_cred(current);
|
|
if (!new) {
|
|
ret = -ENOMEM;
|
|
goto error;
|
|
}
|
|
|
|
if (cache->secctx) {
|
|
ret = set_security_override_from_ctx(new, cache->secctx);
|
|
if (ret < 0) {
|
|
put_cred(new);
|
|
pr_err("Security denies permission to nominate security context: error %d\n",
|
|
ret);
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
cache->cache_cred = new;
|
|
ret = 0;
|
|
error:
|
|
_leave(" = %d", ret);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* see if mkdir and create can be performed in the root directory
|
|
*/
|
|
static int cachefiles_check_cache_dir(struct cachefiles_cache *cache,
|
|
struct dentry *root)
|
|
{
|
|
int ret;
|
|
|
|
ret = security_inode_mkdir(d_backing_inode(root), root, 0);
|
|
if (ret < 0) {
|
|
pr_err("Security denies permission to make dirs: error %d",
|
|
ret);
|
|
return ret;
|
|
}
|
|
|
|
ret = security_inode_create(d_backing_inode(root), root, 0);
|
|
if (ret < 0)
|
|
pr_err("Security denies permission to create files: error %d",
|
|
ret);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* check the security details of the on-disk cache
|
|
* - must be called with security override in force
|
|
* - must return with a security override in force - even in the case of an
|
|
* error
|
|
*/
|
|
int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
|
|
struct dentry *root,
|
|
const struct cred **_saved_cred)
|
|
{
|
|
struct cred *new;
|
|
int ret;
|
|
|
|
_enter("");
|
|
|
|
/* duplicate the cache creds for COW (the override is currently in
|
|
* force, so we can use prepare_creds() to do this) */
|
|
new = prepare_creds();
|
|
if (!new)
|
|
return -ENOMEM;
|
|
|
|
cachefiles_end_secure(cache, *_saved_cred);
|
|
|
|
/* use the cache root dir's security context as the basis with
|
|
* which create files */
|
|
ret = set_create_files_as(new, d_backing_inode(root));
|
|
if (ret < 0) {
|
|
abort_creds(new);
|
|
cachefiles_begin_secure(cache, _saved_cred);
|
|
_leave(" = %d [cfa]", ret);
|
|
return ret;
|
|
}
|
|
|
|
put_cred(cache->cache_cred);
|
|
cache->cache_cred = new;
|
|
|
|
cachefiles_begin_secure(cache, _saved_cred);
|
|
ret = cachefiles_check_cache_dir(cache, root);
|
|
|
|
if (ret == -EOPNOTSUPP)
|
|
ret = 0;
|
|
_leave(" = %d", ret);
|
|
return ret;
|
|
}
|