lib/list_debug.c

   1 /*
   2  * Copyright 2006, Red Hat, Inc., Dave Jones
   3  * Released under the General Public License (GPL).
   4  *
   5  * This file contains the linked list validation and error reporting for
   6  * LIST_HARDENED and DEBUG_LIST.
   7  */
   8
   9 #include <linux/export.h>
  10 #include <linux/list.h>
  11 #include <linux/bug.h>
  12 #include <linux/kernel.h>
  13 #include <linux/rculist.h>
  14
  15 /*
  16  * Check that the data structures for the list manipulations are reasonably
  17  * valid. Failures here indicate memory corruption (and possibly an exploit
  18  * attempt).
  19  */
  20
  21 __list_valid_slowpath
  22 bool __list_add_valid_or_report(struct list_head *new, struct list_head *prev,
  23                                 struct list_head *next)
  24 {
  25         if (CHECK_DATA_CORRUPTION(prev == NULL,
  26                         "list_add corruption. prev is NULL.\n") ||
  27             CHECK_DATA_CORRUPTION(next == NULL,
  28                         "list_add corruption. next is NULL.\n") ||
  29             CHECK_DATA_CORRUPTION(next->prev != prev,
  30                         "list_add corruption. next->prev should be prev (%px), but was %px. (next=%px).\n",
  31                         prev, next->prev, next) ||
  32             CHECK_DATA_CORRUPTION(prev->next != next,
  33                         "list_add corruption. prev->next should be next (%px), but was %px. (prev=%px).\n",
  34                         next, prev->next, prev) ||
  35             CHECK_DATA_CORRUPTION(new == prev || new == next,
  36                         "list_add double add: new=%px, prev=%px, next=%px.\n",
  37                         new, prev, next))
  38                 return false;
  39
  40         return true;
  41 }
  42 EXPORT_SYMBOL(__list_add_valid_or_report);
  43
  44 __list_valid_slowpath
  45 bool __list_del_entry_valid_or_report(struct list_head *entry)
  46 {
  47         struct list_head *prev, *next;
  48
  49         prev = entry->prev;
  50         next = entry->next;
  51
  52         if (CHECK_DATA_CORRUPTION(next == NULL,
  53                         "list_del corruption, %px->next is NULL\n", entry) ||
  54             CHECK_DATA_CORRUPTION(prev == NULL,
  55                         "list_del corruption, %px->prev is NULL\n", entry) ||
  56             CHECK_DATA_CORRUPTION(next == LIST_POISON1,
  57                         "list_del corruption, %px->next is LIST_POISON1 (%px)\n",
  58                         entry, LIST_POISON1) ||
  59             CHECK_DATA_CORRUPTION(prev == LIST_POISON2,
  60                         "list_del corruption, %px->prev is LIST_POISON2 (%px)\n",
  61                         entry, LIST_POISON2) ||
  62             CHECK_DATA_CORRUPTION(prev->next != entry,
  63                         "list_del corruption. prev->next should be %px, but was %px. (prev=%px)\n",
  64                         entry, prev->next, prev) ||
  65             CHECK_DATA_CORRUPTION(next->prev != entry,
  66                         "list_del corruption. next->prev should be %px, but was %px. (next=%px)\n",
  67                         entry, next->prev, next))
  68                 return false;
  69
  70         return true;
  71 }
  72 EXPORT_SYMBOL(__list_del_entry_valid_or_report);