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                 COMMON_AUDIT_DATA_INIT(&sa, NONE);
  69                 sa.aad.info = str;
  70                 aa_audit_msg(AUDIT_APPARMOR_STATUS, &sa, NULL);
  71         }
  72         printk(KERN_INFO "AppArmor: %s\n", str);
  73 }
  74
  75 /**
  76  * kvmalloc - do allocation preferring kmalloc but falling back to vmalloc
  77  * @size: size of allocation
  78  *
  79  * Return: allocated buffer or NULL if failed
  80  *
  81  * It is possible that policy being loaded from the user is larger than
  82  * what can be allocated by kmalloc, in those cases fall back to vmalloc.
  83  */
  84 void *kvmalloc(size_t size)
  85 {
  86         void *buffer = NULL;
  87
  88         if (size == 0)
  89                 return NULL;
  90
  91         /* do not attempt kmalloc if we need more than 16 pages at once */
  92         if (size <= (16*PAGE_SIZE))
  93                 buffer = kmalloc(size, GFP_NOIO | __GFP_NOWARN);
  94         if (!buffer) {
  95                 /* see kvfree for why size must be at least work_struct size
  96                  * when allocated via vmalloc
  97                  */
  98                 if (size < sizeof(struct work_struct))
  99                         size = sizeof(struct work_struct);
 100                 buffer = vmalloc(size);
 101         }
 102         return buffer;
 103 }
 104
 105 /**
 106  * do_vfree - workqueue routine for freeing vmalloced memory
 107  * @work: data to be freed
 108  *
 109  * The work_struct is overlaid to the data being freed, as at the point
 110  * the work is scheduled the data is no longer valid, be its freeing
 111  * needs to be delayed until safe.
 112  */
 113 static void do_vfree(struct work_struct *work)
 114 {
 115         vfree(work);
 116 }
 117
 118 /**
 119  * kvfree - free an allocation do by kvmalloc
 120  * @buffer: buffer to free (MAYBE_NULL)
 121  *
 122  * Free a buffer allocated by kvmalloc
 123  */
 124 void kvfree(void *buffer)
 125 {
 126         if (is_vmalloc_addr(buffer)) {
 127                 /* Data is no longer valid so just use the allocated space
 128                  * as the work_struct
 129                  */
 130                 struct work_struct *work = (struct work_struct *) buffer;
 131                 INIT_WORK(work, do_vfree);
 132                 schedule_work(work);
 133         } else
 134                 kfree(buffer);
 135 }