/* 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);			printk(KERN_ERR "CacheFiles:"			       " 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(root->d_inode, root, 0);	if (ret < 0) {		printk(KERN_ERR "CacheFiles:"		       " Security denies permission to make dirs: error %d",		       ret);		return ret;	} 	ret = security_inode_create(root->d_inode, root, 0);	if (ret < 0)		printk(KERN_ERR "CacheFiles:"		       " 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, root->d_inode);	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;}