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