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); 73