| 1 | /* |
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| 2 | * Copyright 2006, Red Hat, Inc., Dave Jones |
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| 3 | * Released under the General Public License (GPL). |
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| 4 | * |
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| 5 | * This file contains the linked list validation and error reporting for |
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| 6 | * LIST_HARDENED and DEBUG_LIST. |
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| 7 | */ |
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| 8 | |
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| 9 | #include <linux/export.h> |
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| 10 | #include <linux/list.h> |
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| 11 | #include <linux/bug.h> |
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| 12 | #include <linux/kernel.h> |
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| 13 | #include <linux/rculist.h> |
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| 14 | |
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| 15 | /* |
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| 16 | * Check that the data structures for the list manipulations are reasonably |
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| 17 | * valid. Failures here indicate memory corruption (and possibly an exploit |
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| 18 | * attempt). |
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| 19 | */ |
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| 20 | |
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| 21 | __list_valid_slowpath |
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| 22 | bool __list_add_valid_or_report(struct list_head *new, struct list_head *prev, |
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| 23 | struct list_head *next) |
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| 24 | { |
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| 25 | if (CHECK_DATA_CORRUPTION(prev == NULL, NULL, |
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| 26 | "list_add corruption. prev is NULL.\n" ) || |
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| 27 | CHECK_DATA_CORRUPTION(next == NULL, NULL, |
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| 28 | "list_add corruption. next is NULL.\n" ) || |
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| 29 | CHECK_DATA_CORRUPTION(next->prev != prev, next, |
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| 30 | "list_add corruption. next->prev should be prev (%px), but was %px. (next=%px).\n" , |
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| 31 | prev, next->prev, next) || |
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| 32 | CHECK_DATA_CORRUPTION(prev->next != next, prev, |
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| 33 | "list_add corruption. prev->next should be next (%px), but was %px. (prev=%px).\n" , |
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| 34 | next, prev->next, prev) || |
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| 35 | CHECK_DATA_CORRUPTION(new == prev || new == next, NULL, |
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| 36 | "list_add double add: new=%px, prev=%px, next=%px.\n" , |
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| 37 | new, prev, next)) |
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| 38 | return false; |
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| 39 | |
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| 40 | return true; |
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| 41 | } |
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| 42 | EXPORT_SYMBOL(__list_add_valid_or_report); |
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| 43 | |
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| 44 | __list_valid_slowpath |
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| 45 | bool __list_del_entry_valid_or_report(struct list_head *entry) |
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| 46 | { |
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| 47 | struct list_head *prev, *next; |
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| 48 | |
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| 49 | prev = entry->prev; |
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| 50 | next = entry->next; |
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| 51 | |
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| 52 | if (CHECK_DATA_CORRUPTION(next == NULL, NULL, |
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| 53 | "list_del corruption, %px->next is NULL\n" , entry) || |
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| 54 | CHECK_DATA_CORRUPTION(prev == NULL, NULL, |
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| 55 | "list_del corruption, %px->prev is NULL\n" , entry) || |
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| 56 | CHECK_DATA_CORRUPTION(next == LIST_POISON1, next, |
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| 57 | "list_del corruption, %px->next is LIST_POISON1 (%px)\n" , |
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| 58 | entry, LIST_POISON1) || |
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| 59 | CHECK_DATA_CORRUPTION(prev == LIST_POISON2, prev, |
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| 60 | "list_del corruption, %px->prev is LIST_POISON2 (%px)\n" , |
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| 61 | entry, LIST_POISON2) || |
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| 62 | CHECK_DATA_CORRUPTION(prev->next != entry, prev, |
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| 63 | "list_del corruption. prev->next should be %px, but was %px. (prev=%px)\n" , |
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| 64 | entry, prev->next, prev) || |
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| 65 | CHECK_DATA_CORRUPTION(next->prev != entry, next, |
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| 66 | "list_del corruption. next->prev should be %px, but was %px. (next=%px)\n" , |
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| 67 | entry, next->prev, next)) |
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| 68 | return false; |
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| 69 | |
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| 70 | return true; |
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| 71 | } |
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| 72 | EXPORT_SYMBOL(__list_del_entry_valid_or_report); |
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| 73 | |
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