linux/security/apparmor/lib.c

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/*
* AppArmor security module
*
* This file contains basic common functions used in AppArmor
*
* Copyright (C) 1998-2008 Novell/SUSE
* Copyright 2009-2010 Canonical Ltd.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, version 2 of the
* License.
*/
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/vmalloc.h>
#include "include/audit.h"
/**
* aa_split_fqname - split a fqname into a profile and namespace name
* @fqname: a full qualified name in namespace profile format (NOT NULL)
* @ns_name: pointer to portion of the string containing the ns name (NOT NULL)
*
* Returns: profile name or NULL if one is not specified
*
* Split a namespace name from a profile name (see policy.c for naming
* description). If a portion of the name is missing it returns NULL for
* that portion.
*
* NOTE: may modify the @fqname string. The pointers returned point
* into the @fqname string.
*/
char *aa_split_fqname(char *fqname, char **ns_name)
{
char *name = strim(fqname);
*ns_name = NULL;
if (name[0] == ':') {
char *split = strchr(&name[1], ':');
*ns_name = skip_spaces(&name[1]);
if (split) {
/* overwrite ':' with \0 */
*split = 0;
name = skip_spaces(split + 1);
} else
/* a ns name without a following profile is allowed */
name = NULL;
}
if (name && *name == 0)
name = NULL;
return name;
}
/**
* aa_info_message - log a none profile related status message
* @str: message to log
*/
void aa_info_message(const char *str)
{
if (audit_enabled) {
struct common_audit_data sa;
COMMON_AUDIT_DATA_INIT(&sa, NONE);
sa.aad.info = str;
aa_audit_msg(AUDIT_APPARMOR_STATUS, &sa, NULL);
}
printk(KERN_INFO "AppArmor: %s\n", str);
}
/**
* kvmalloc - do allocation preferring kmalloc but falling back to vmalloc
* @size: size of allocation
*
* Return: allocated buffer or NULL if failed
*
* It is possible that policy being loaded from the user is larger than
* what can be allocated by kmalloc, in those cases fall back to vmalloc.
*/
void *kvmalloc(size_t size)
{
void *buffer = NULL;
if (size == 0)
return NULL;
/* do not attempt kmalloc if we need more than 16 pages at once */
if (size <= (16*PAGE_SIZE))
buffer = kmalloc(size, GFP_NOIO | __GFP_NOWARN);
if (!buffer) {
/* see kvfree for why size must be at least work_struct size
* when allocated via vmalloc
*/
if (size < sizeof(struct work_struct))
size = sizeof(struct work_struct);
buffer = vmalloc(size);
}
return buffer;
}
/**
* do_vfree - workqueue routine for freeing vmalloced memory
* @work: data to be freed
*
* The work_struct is overlaid to the data being freed, as at the point
* the work is scheduled the data is no longer valid, be its freeing
* needs to be delayed until safe.
*/
static void do_vfree(struct work_struct *work)
{
vfree(work);
}
/**
* kvfree - free an allocation do by kvmalloc
* @buffer: buffer to free (MAYBE_NULL)
*
* Free a buffer allocated by kvmalloc
*/
void kvfree(void *buffer)
{
if (is_vmalloc_addr(buffer)) {
/* Data is no longer valid so just use the allocated space
* as the work_struct
*/
struct work_struct *work = (struct work_struct *) buffer;
INIT_WORK(work, do_vfree);
schedule_work(work);
} else
kfree(buffer);
}