lib/test_kasan_module.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *
   4  * Copyright (c) 2014 Samsung Electronics Co., Ltd.
   5  * Author: Andrey Ryabinin <a.ryabinin@samsung.com>
   6  */
   7
   8 #define pr_fmt(fmt) "kasan test: %s " fmt, __func__
   9
  10 #include <linux/mman.h>
  11 #include <linux/module.h>
  12 #include <linux/printk.h>
  13 #include <linux/slab.h>
  14 #include <linux/uaccess.h>
  15
  16 #include "../mm/kasan/kasan.h"
  17
  18 #define OOB_TAG_OFF (IS_ENABLED(CONFIG_KASAN_GENERIC) ? 0 : KASAN_GRANULE_SIZE)
  19
  20 static noinline void __init copy_user_test(void)
  21 {
  22         char *kmem;
  23         char __user *usermem;
  24         size_t size = 10;
  25         int unused;
  26
  27         kmem = kmalloc(size, GFP_KERNEL);
  28         if (!kmem)
  29                 return;
  30
  31         usermem = (char __user *)vm_mmap(NULL, 0, PAGE_SIZE,
  32                             PROT_READ | PROT_WRITE | PROT_EXEC,
  33                             MAP_ANONYMOUS | MAP_PRIVATE, 0);
  34         if (IS_ERR(usermem)) {
  35                 pr_err("Failed to allocate user memory\n");
  36                 kfree(kmem);
  37                 return;
  38         }
  39
  40         pr_info("out-of-bounds in copy_from_user()\n");
  41         unused = copy_from_user(kmem, usermem, size + 1 + OOB_TAG_OFF);
  42
  43         pr_info("out-of-bounds in copy_to_user()\n");
  44         unused = copy_to_user(usermem, kmem, size + 1 + OOB_TAG_OFF);
  45
  46         pr_info("out-of-bounds in __copy_from_user()\n");
  47         unused = __copy_from_user(kmem, usermem, size + 1 + OOB_TAG_OFF);
  48
  49         pr_info("out-of-bounds in __copy_to_user()\n");
  50         unused = __copy_to_user(usermem, kmem, size + 1 + OOB_TAG_OFF);
  51
  52         pr_info("out-of-bounds in __copy_from_user_inatomic()\n");
  53         unused = __copy_from_user_inatomic(kmem, usermem, size + 1 + OOB_TAG_OFF);
  54
  55         pr_info("out-of-bounds in __copy_to_user_inatomic()\n");
  56         unused = __copy_to_user_inatomic(usermem, kmem, size + 1 + OOB_TAG_OFF);
  57
  58         pr_info("out-of-bounds in strncpy_from_user()\n");
  59         unused = strncpy_from_user(kmem, usermem, size + 1 + OOB_TAG_OFF);
  60
  61         vm_munmap((unsigned long)usermem, PAGE_SIZE);
  62         kfree(kmem);
  63 }
  64
  65 static struct kasan_rcu_info {
  66         int i;
  67         struct rcu_head rcu;
  68 } *global_rcu_ptr;
  69
  70 static noinline void __init kasan_rcu_reclaim(struct rcu_head *rp)
  71 {
  72         struct kasan_rcu_info *fp = container_of(rp,
  73                                                 struct kasan_rcu_info, rcu);
  74
  75         kfree(fp);
  76         fp->i = 1;
  77 }
  78
  79 static noinline void __init kasan_rcu_uaf(void)
  80 {
  81         struct kasan_rcu_info *ptr;
  82
  83         pr_info("use-after-free in kasan_rcu_reclaim\n");
  84         ptr = kmalloc(sizeof(struct kasan_rcu_info), GFP_KERNEL);
  85         if (!ptr) {
  86                 pr_err("Allocation failed\n");
  87                 return;
  88         }
  89
  90         global_rcu_ptr = rcu_dereference_protected(ptr, NULL);
  91         call_rcu(&global_rcu_ptr->rcu, kasan_rcu_reclaim);
  92 }
  93
  94 static noinline void __init kasan_workqueue_work(struct work_struct *work)
  95 {
  96         kfree(work);
  97 }
  98
  99 static noinline void __init kasan_workqueue_uaf(void)
 100 {
 101         struct workqueue_struct *workqueue;
 102         struct work_struct *work;
 103
 104         workqueue = create_workqueue("kasan_wq_test");
 105         if (!workqueue) {
 106                 pr_err("Allocation failed\n");
 107                 return;
 108         }
 109         work = kmalloc(sizeof(struct work_struct), GFP_KERNEL);
 110         if (!work) {
 111                 pr_err("Allocation failed\n");
 112                 return;
 113         }
 114
 115         INIT_WORK(work, kasan_workqueue_work);
 116         queue_work(workqueue, work);
 117         destroy_workqueue(workqueue);
 118
 119         pr_info("use-after-free on workqueue\n");
 120         ((volatile struct work_struct *)work)->data;
 121 }
 122
 123 static int __init test_kasan_module_init(void)
 124 {
 125         /*
 126          * Temporarily enable multi-shot mode. Otherwise, KASAN would only
 127          * report the first detected bug and panic the kernel if panic_on_warn
 128          * is enabled.
 129          */
 130         bool multishot = kasan_save_enable_multi_shot();
 131
 132         copy_user_test();
 133         kasan_rcu_uaf();
 134         kasan_workqueue_uaf();
 135
 136         kasan_restore_multi_shot(multishot);
 137         return -EAGAIN;
 138 }
 139
 140 module_init(test_kasan_module_init);
 141 MODULE_LICENSE("GPL");