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/mm.h>
  16#include <linux/slab.h>
  17#include <linux/string.h>
  18#include <linux/vmalloc.h>
  19
  20#include "include/audit.h"
  21#include "include/apparmor.h"
  22
  23
  24/**
  25 * aa_split_fqname - split a fqname into a profile and namespace name
  26 * @fqname: a full qualified name in namespace profile format (NOT NULL)
  27 * @ns_name: pointer to portion of the string containing the ns name (NOT NULL)
  28 *
  29 * Returns: profile name or NULL if one is not specified
  30 *
  31 * Split a namespace name from a profile name (see policy.c for naming
  32 * description).  If a portion of the name is missing it returns NULL for
  33 * that portion.
  34 *
  35 * NOTE: may modify the @fqname string.  The pointers returned point
  36 *       into the @fqname string.
  37 */
  38char *aa_split_fqname(char *fqname, char **ns_name)
  39{
  40        char *name = strim(fqname);
  41
  42        *ns_name = NULL;
  43        if (name[0] == ':') {
  44                char *split = strchr(&name[1], ':');
  45                *ns_name = skip_spaces(&name[1]);
  46                if (split) {
  47                        /* overwrite ':' with \0 */
  48                        *split = 0;
  49                        name = skip_spaces(split + 1);
  50                } else
  51                        /* a ns name without a following profile is allowed */
  52                        name = NULL;
  53        }
  54        if (name && *name == 0)
  55                name = NULL;
  56
  57        return name;
  58}
  59
  60/**
  61 * aa_info_message - log a none profile related status message
  62 * @str: message to log
  63 */
  64void aa_info_message(const char *str)
  65{
  66        if (audit_enabled) {
  67                struct common_audit_data sa;
  68                struct apparmor_audit_data aad = {0,};
  69                sa.type = LSM_AUDIT_DATA_NONE;
  70                sa.aad = &aad;
  71                aad.info = str;
  72                aa_audit_msg(AUDIT_APPARMOR_STATUS, &sa, NULL);
  73        }
  74        printk(KERN_INFO "AppArmor: %s\n", str);
  75}
  76
  77/**
  78 * kvmalloc - do allocation preferring kmalloc but falling back to vmalloc
  79 * @size: size of allocation
  80 *
  81 * Return: allocated buffer or NULL if failed
  82 *
  83 * It is possible that policy being loaded from the user is larger than
  84 * what can be allocated by kmalloc, in those cases fall back to vmalloc.
  85 */
  86void *kvmalloc(size_t size)
  87{
  88        void *buffer = NULL;
  89
  90        if (size == 0)
  91                return NULL;
  92
  93        /* do not attempt kmalloc if we need more than 16 pages at once */
  94        if (size <= (16*PAGE_SIZE))
  95                buffer = kmalloc(size, GFP_NOIO | __GFP_NOWARN);
  96        if (!buffer) {
  97                /* see kvfree for why size must be at least work_struct size
  98                 * when allocated via vmalloc
  99                 */
 100                if (size < sizeof(struct work_struct))
 101                        size = sizeof(struct work_struct);
 102                buffer = vmalloc(size);
 103        }
 104        return buffer;
 105}
 106
 107/**
 108 * do_vfree - workqueue routine for freeing vmalloced memory
 109 * @work: data to be freed
 110 *
 111 * The work_struct is overlaid to the data being freed, as at the point
 112 * the work is scheduled the data is no longer valid, be its freeing
 113 * needs to be delayed until safe.
 114 */
 115static void do_vfree(struct work_struct *work)
 116{
 117        vfree(work);
 118}
 119
 120/**
 121 * kvfree - free an allocation do by kvmalloc
 122 * @buffer: buffer to free (MAYBE_NULL)
 123 *
 124 * Free a buffer allocated by kvmalloc
 125 */
 126void kvfree(void *buffer)
 127{
 128        if (is_vmalloc_addr(buffer)) {
 129                /* Data is no longer valid so just use the allocated space
 130                 * as the work_struct
 131                 */
 132                struct work_struct *work = (struct work_struct *) buffer;
 133                INIT_WORK(work, do_vfree);
 134                schedule_work(work);
 135        } else
 136                kfree(buffer);
 137}
 138