root/mm/kasan/generic_report.c

DEFINITIONS

1. find_first_bad_addr
2. get_shadow_bug_type
3. get_wild_bug_type
4. get_bug_type
5. __asan_report_load_n_noabort
6. __asan_report_store_n_noabort

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * This file contains generic KASAN specific error reporting code.
   4  *
   5  * Copyright (c) 2014 Samsung Electronics Co., Ltd.
   6  * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
   7  *
   8  * Some code borrowed from https://github.com/xairy/kasan-prototype by
   9  *        Andrey Konovalov <andreyknvl@gmail.com>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  *
  15  */
  16 
  17 #include <linux/bitops.h>
  18 #include <linux/ftrace.h>
  19 #include <linux/init.h>
  20 #include <linux/kernel.h>
  21 #include <linux/mm.h>
  22 #include <linux/printk.h>
  23 #include <linux/sched.h>
  24 #include <linux/slab.h>
  25 #include <linux/stackdepot.h>
  26 #include <linux/stacktrace.h>
  27 #include <linux/string.h>
  28 #include <linux/types.h>
  29 #include <linux/kasan.h>
  30 #include <linux/module.h>
  31 
  32 #include <asm/sections.h>
  33 
  34 #include "kasan.h"
  35 #include "../slab.h"
  36 
  37 void *find_first_bad_addr(void *addr, size_t size)
  38 {
  39         void *p = addr;
  40 
  41         while (p < addr + size && !(*(u8 *)kasan_mem_to_shadow(p)))
  42                 p += KASAN_SHADOW_SCALE_SIZE;
  43         return p;
  44 }
  45 
  46 static const char *get_shadow_bug_type(struct kasan_access_info *info)
  47 {
  48         const char *bug_type = "unknown-crash";
  49         u8 *shadow_addr;
  50 
  51         shadow_addr = (u8 *)kasan_mem_to_shadow(info->first_bad_addr);
  52 
  53         /*
  54          * If shadow byte value is in [0, KASAN_SHADOW_SCALE_SIZE) we can look
  55          * at the next shadow byte to determine the type of the bad access.
  56          */
  57         if (*shadow_addr > 0 && *shadow_addr <= KASAN_SHADOW_SCALE_SIZE - 1)
  58                 shadow_addr++;
  59 
  60         switch (*shadow_addr) {
  61         case 0 ... KASAN_SHADOW_SCALE_SIZE - 1:
  62                 /*
  63                  * In theory it's still possible to see these shadow values
  64                  * due to a data race in the kernel code.
  65                  */
  66                 bug_type = "out-of-bounds";
  67                 break;
  68         case KASAN_PAGE_REDZONE:
  69         case KASAN_KMALLOC_REDZONE:
  70                 bug_type = "slab-out-of-bounds";
  71                 break;
  72         case KASAN_GLOBAL_REDZONE:
  73                 bug_type = "global-out-of-bounds";
  74                 break;
  75         case KASAN_STACK_LEFT:
  76         case KASAN_STACK_MID:
  77         case KASAN_STACK_RIGHT:
  78         case KASAN_STACK_PARTIAL:
  79                 bug_type = "stack-out-of-bounds";
  80                 break;
  81         case KASAN_FREE_PAGE:
  82         case KASAN_KMALLOC_FREE:
  83                 bug_type = "use-after-free";
  84                 break;
  85         case KASAN_ALLOCA_LEFT:
  86         case KASAN_ALLOCA_RIGHT:
  87                 bug_type = "alloca-out-of-bounds";
  88                 break;
  89         }
  90 
  91         return bug_type;
  92 }
  93 
  94 static const char *get_wild_bug_type(struct kasan_access_info *info)
  95 {
  96         const char *bug_type = "unknown-crash";
  97 
  98         if ((unsigned long)info->access_addr < PAGE_SIZE)
  99                 bug_type = "null-ptr-deref";
 100         else if ((unsigned long)info->access_addr < TASK_SIZE)
 101                 bug_type = "user-memory-access";
 102         else
 103                 bug_type = "wild-memory-access";
 104 
 105         return bug_type;
 106 }
 107 
 108 const char *get_bug_type(struct kasan_access_info *info)
 109 {
 110         if (addr_has_shadow(info->access_addr))
 111                 return get_shadow_bug_type(info);
 112         return get_wild_bug_type(info);
 113 }
 114 
 115 #define DEFINE_ASAN_REPORT_LOAD(size)                     \
 116 void __asan_report_load##size##_noabort(unsigned long addr) \
 117 {                                                         \
 118         kasan_report(addr, size, false, _RET_IP_);        \
 119 }                                                         \
 120 EXPORT_SYMBOL(__asan_report_load##size##_noabort)
 121 
 122 #define DEFINE_ASAN_REPORT_STORE(size)                     \
 123 void __asan_report_store##size##_noabort(unsigned long addr) \
 124 {                                                          \
 125         kasan_report(addr, size, true, _RET_IP_);          \
 126 }                                                          \
 127 EXPORT_SYMBOL(__asan_report_store##size##_noabort)
 128 
 129 DEFINE_ASAN_REPORT_LOAD(1);
 130 DEFINE_ASAN_REPORT_LOAD(2);
 131 DEFINE_ASAN_REPORT_LOAD(4);
 132 DEFINE_ASAN_REPORT_LOAD(8);
 133 DEFINE_ASAN_REPORT_LOAD(16);
 134 DEFINE_ASAN_REPORT_STORE(1);
 135 DEFINE_ASAN_REPORT_STORE(2);
 136 DEFINE_ASAN_REPORT_STORE(4);
 137 DEFINE_ASAN_REPORT_STORE(8);
 138 DEFINE_ASAN_REPORT_STORE(16);
 139 
 140 void __asan_report_load_n_noabort(unsigned long addr, size_t size)
 141 {
 142         kasan_report(addr, size, false, _RET_IP_);
 143 }
 144 EXPORT_SYMBOL(__asan_report_load_n_noabort);
 145 
 146 void __asan_report_store_n_noabort(unsigned long addr, size_t size)
 147 {
 148         kasan_report(addr, size, true, _RET_IP_);
 149 }
 150 EXPORT_SYMBOL(__asan_report_store_n_noabort);