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de54ebbe26
The kernel checks for cases of data structure corruption under some
CONFIGs (e.g. CONFIG_DEBUG_LIST). When corruption is detected, some
systems may want to BUG() immediately instead of letting the system run
with known corruption. Usually these kinds of manipulation primitives can
be used by security flaws to gain arbitrary memory write control. This
provides a new config CONFIG_BUG_ON_DATA_CORRUPTION and a corresponding
macro CHECK_DATA_CORRUPTION for handling these situations. Notably, even
if not BUGing, the kernel should not continue processing the corrupted
structure.
This is inspired by similar hardening by Syed Rameez Mustafa in MSM
kernels, and in PaX and Grsecurity, which is likely in response to earlier
removal of the BUG calls in commit 924d9addb9 ("list debugging: use
WARN() instead of BUG()").
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Rik van Riel <riel@redhat.com>
59 lines
1.7 KiB
C
59 lines
1.7 KiB
C
/*
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* Copyright 2006, Red Hat, Inc., Dave Jones
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* Released under the General Public License (GPL).
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*
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* This file contains the linked list validation for DEBUG_LIST.
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*/
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#include <linux/export.h>
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#include <linux/list.h>
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#include <linux/bug.h>
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#include <linux/kernel.h>
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#include <linux/rculist.h>
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/*
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* Check that the data structures for the list manipulations are reasonably
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* valid. Failures here indicate memory corruption (and possibly an exploit
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* attempt).
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*/
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bool __list_add_valid(struct list_head *new, struct list_head *prev,
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struct list_head *next)
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{
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CHECK_DATA_CORRUPTION(next->prev != prev,
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"list_add corruption. next->prev should be prev (%p), but was %p. (next=%p).\n",
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prev, next->prev, next);
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CHECK_DATA_CORRUPTION(prev->next != next,
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"list_add corruption. prev->next should be next (%p), but was %p. (prev=%p).\n",
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next, prev->next, prev);
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CHECK_DATA_CORRUPTION(new == prev || new == next,
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"list_add double add: new=%p, prev=%p, next=%p.\n",
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new, prev, next);
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return true;
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}
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EXPORT_SYMBOL(__list_add_valid);
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bool __list_del_entry_valid(struct list_head *entry)
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{
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struct list_head *prev, *next;
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prev = entry->prev;
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next = entry->next;
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CHECK_DATA_CORRUPTION(next == LIST_POISON1,
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"list_del corruption, %p->next is LIST_POISON1 (%p)\n",
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entry, LIST_POISON1);
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CHECK_DATA_CORRUPTION(prev == LIST_POISON2,
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"list_del corruption, %p->prev is LIST_POISON2 (%p)\n",
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entry, LIST_POISON2);
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CHECK_DATA_CORRUPTION(prev->next != entry,
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"list_del corruption. prev->next should be %p, but was %p\n",
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entry, prev->next);
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CHECK_DATA_CORRUPTION(next->prev != entry,
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"list_del corruption. next->prev should be %p, but was %p\n",
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entry, next->prev);
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return true;
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}
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EXPORT_SYMBOL(__list_del_entry_valid);
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