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  */
  36 char *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  */
  62 void 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  */
  82 void *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  */
 111 static 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  */
 122 void 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 }