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  */
  38 char *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  */
  64 void 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  */
  86 void *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  */
 115 static 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  */
 126 void 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 }