a29815a333
The list macros use LIST_POISON1 and LIST_POISON2 as undereferencable pointers in order to trap erronous use of freed list_heads. Unfortunately userspace can arrange for those pointers to actually be dereferencable, potentially turning an oops to an expolit. To avoid this allow architectures (currently x86_64 only) to override the default values for these pointers with truly-undereferencable values. This is easy on x86_64 as the virtual address space is large and contains areas that cannot be mapped. Other 64-bit architectures will likely find similar unmapped ranges. [ingo: switch to 0xdead000000000000 as the unmapped area] [ingo: add comments, cleanup] [jaswinder: eliminate sparse warnings] Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
90 lines
2.5 KiB
C
90 lines
2.5 KiB
C
#ifndef _LINUX_POISON_H
|
|
#define _LINUX_POISON_H
|
|
|
|
/********** include/linux/list.h **********/
|
|
|
|
/*
|
|
* Architectures might want to move the poison pointer offset
|
|
* into some well-recognized area such as 0xdead000000000000,
|
|
* that is also not mappable by user-space exploits:
|
|
*/
|
|
#ifdef CONFIG_ILLEGAL_POINTER_VALUE
|
|
# define POISON_POINTER_DELTA _AC(CONFIG_ILLEGAL_POINTER_VALUE, UL)
|
|
#else
|
|
# define POISON_POINTER_DELTA 0
|
|
#endif
|
|
|
|
/*
|
|
* These are non-NULL pointers that will result in page faults
|
|
* under normal circumstances, used to verify that nobody uses
|
|
* non-initialized list entries.
|
|
*/
|
|
#define LIST_POISON1 ((void *) 0x00100100 + POISON_POINTER_DELTA)
|
|
#define LIST_POISON2 ((void *) 0x00200200 + POISON_POINTER_DELTA)
|
|
|
|
/********** include/linux/timer.h **********/
|
|
/*
|
|
* Magic number "tsta" to indicate a static timer initializer
|
|
* for the object debugging code.
|
|
*/
|
|
#define TIMER_ENTRY_STATIC ((void *) 0x74737461)
|
|
|
|
/********** mm/debug-pagealloc.c **********/
|
|
#define PAGE_POISON 0xaa
|
|
|
|
/********** mm/slab.c **********/
|
|
/*
|
|
* Magic nums for obj red zoning.
|
|
* Placed in the first word before and the first word after an obj.
|
|
*/
|
|
#define RED_INACTIVE 0x09F911029D74E35BULL /* when obj is inactive */
|
|
#define RED_ACTIVE 0xD84156C5635688C0ULL /* when obj is active */
|
|
|
|
#define SLUB_RED_INACTIVE 0xbb
|
|
#define SLUB_RED_ACTIVE 0xcc
|
|
|
|
/* ...and for poisoning */
|
|
#define POISON_INUSE 0x5a /* for use-uninitialised poisoning */
|
|
#define POISON_FREE 0x6b /* for use-after-free poisoning */
|
|
#define POISON_END 0xa5 /* end-byte of poisoning */
|
|
|
|
/********** arch/$ARCH/mm/init.c **********/
|
|
#define POISON_FREE_INITMEM 0xcc
|
|
|
|
/********** arch/ia64/hp/common/sba_iommu.c **********/
|
|
/*
|
|
* arch/ia64/hp/common/sba_iommu.c uses a 16-byte poison string with a
|
|
* value of "SBAIOMMU POISON\0" for spill-over poisoning.
|
|
*/
|
|
|
|
/********** fs/jbd/journal.c **********/
|
|
#define JBD_POISON_FREE 0x5b
|
|
#define JBD2_POISON_FREE 0x5c
|
|
|
|
/********** drivers/base/dmapool.c **********/
|
|
#define POOL_POISON_FREED 0xa7 /* !inuse */
|
|
#define POOL_POISON_ALLOCATED 0xa9 /* !initted */
|
|
|
|
/********** drivers/atm/ **********/
|
|
#define ATM_POISON_FREE 0x12
|
|
#define ATM_POISON 0xdeadbeef
|
|
|
|
/********** net/ **********/
|
|
#define NEIGHBOR_DEAD 0xdeadbeef
|
|
#define NETFILTER_LINK_POISON 0xdead57ac
|
|
|
|
/********** kernel/mutexes **********/
|
|
#define MUTEX_DEBUG_INIT 0x11
|
|
#define MUTEX_DEBUG_FREE 0x22
|
|
|
|
/********** lib/flex_array.c **********/
|
|
#define FLEX_ARRAY_FREE 0x6c /* for use-after-free poisoning */
|
|
|
|
/********** security/ **********/
|
|
#define KEY_DESTROY 0xbd
|
|
|
|
/********** sound/oss/ **********/
|
|
#define OSS_POISON_FREE 0xAB
|
|
|
|
#endif
|