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
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