LXR linux/security/apparmor/lib.c

   1/*
   2 * AppArmor security module
   3 *
   4 * This file contains basic common functions used in AppArmor
   5 *
   6 * Copyright (C) 1998-2008 Novell/SUSE
   7 * Copyright 2009-2010 Canonical Ltd.
   8 *
   9 * This program is free software; you can redistribute it and/or
  10 * modify it under the terms of the GNU General Public License as
  11 * published by the Free Software Foundation, version 2 of the
  12 * License.
  13 */
  14
  15#include <linux/slab.h>
  16#include <linux/string.h>
  17#include <linux/vmalloc.h>
  18
  19#include "include/audit.h"
  20
  21
  22/**
  23 * aa_split_fqname - split a fqname into a profile and namespace name
  24 * @fqname: a full qualified name in namespace profile format (NOT NULL)
  25 * @ns_name: pointer to portion of the string containing the ns name (NOT NULL)
  26 *
  27 * Returns: profile name or NULL if one is not specified
  28 *
  29 * Split a namespace name from a profile name (see policy.c for naming
  30 * description).  If a portion of the name is missing it returns NULL for
  31 * that portion.
  32 *
  33 * NOTE: may modify the @fqname string.  The pointers returned point
  34 *       into the @fqname string.
  35 */
  36char *aa_split_fqname(char *fqname, char **ns_name)
  37{
  38        char *name = strim(fqname);
  39
  40        *ns_name = NULL;
  41        if (name[0] == ':') {
  42                char *split = strchr(&name[1], ':');
  43                *ns_name = skip_spaces(&name[1]);
  44                if (split) {
  45                        /* overwrite ':' with \0 */
  46                        *split = 0;
  47                        name = skip_spaces(split + 1);
  48                } else
  49                        /* a ns name without a following profile is allowed */
  50                        name = NULL;
  51        }
  52        if (name && *name == 0)
  53                name = NULL;
  54
  55        return name;
  56}
  57
  58/**
  59 * aa_info_message - log a none profile related status message
  60 * @str: message to log
  61 */
  62void aa_info_message(const char *str)
  63{
  64        if (audit_enabled) {
  65                struct common_audit_data sa;
  66                COMMON_AUDIT_DATA_INIT(&sa, NONE);
  67                sa.aad.info = str;
  68                aa_audit_msg(AUDIT_APPARMOR_STATUS, &sa, NULL);
  69        }
  70        printk(KERN_INFO "AppArmor: %s\n", str);
  71}
  72
  73/**
  74 * kvmalloc - do allocation preferring kmalloc but falling back to vmalloc
  75 * @size: size of allocation
  76 *
  77 * Return: allocated buffer or NULL if failed
  78 *
  79 * It is possible that policy being loaded from the user is larger than
  80 * what can be allocated by kmalloc, in those cases fall back to vmalloc.
  81 */
  82void *kvmalloc(size_t size)
  83{
  84        void *buffer = NULL;
  85
  86        if (size == 0)
  87                return NULL;
  88
  89        /* do not attempt kmalloc if we need more than 16 pages at once */
  90        if (size <= (16*PAGE_SIZE))
  91                buffer = kmalloc(size, GFP_NOIO | __GFP_NOWARN);
  92        if (!buffer) {
  93                /* see kvfree for why size must be at least work_struct size
  94                 * when allocated via vmalloc
  95                 */
  96                if (size < sizeof(struct work_struct))
  97                        size = sizeof(struct work_struct);
  98                buffer = vmalloc(size);
  99        }
 100        return buffer;
 101}
 102
 103/**
 104 * do_vfree - workqueue routine for freeing vmalloced memory
 105 * @work: data to be freed
 106 *
 107 * The work_struct is overlaid to the data being freed, as at the point
 108 * the work is scheduled the data is no longer valid, be its freeing
 109 * needs to be delayed until safe.
 110 */
 111static void do_vfree(struct work_struct *work)
 112{
 113        vfree(work);
 114}
 115
 116/**
 117 * kvfree - free an allocation do by kvmalloc
 118 * @buffer: buffer to free (MAYBE_NULL)
 119 *
 120 * Free a buffer allocated by kvmalloc
 121 */
 122void kvfree(void *buffer)
 123{
 124        if (is_vmalloc_addr(buffer)) {
 125                /* Data is no longer valid so just use the allocated space
 126                 * as the work_struct
 127                 */
 128                struct work_struct *work = (struct work_struct *) buffer;
 129                INIT_WORK(work, do_vfree);
 130                schedule_work(work);
 131        } else
 132                kfree(buffer);
 133}
 134