The patch titled Make LIST_POISON less deadly has been removed from the -mm tree. Its filename was make-list_poison-less-deadly-v2.patch This patch was dropped because it was merged into mainline or a subsystem tree The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: Make LIST_POISON less deadly From: Avi Kivity <avi@xxxxxxxxxxxx> 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-undereferncable values. This is easy on x86_64 as the virtual address space is smaller than the range spanned by pointer values. Signed-off-by: Avi Kivity <avi@xxxxxxxxxxxx> Cc: <linux-arch@xxxxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/x86/Kconfig | 5 +++++ include/linux/poison.h | 10 ++++++++-- 2 files changed, 13 insertions(+), 2 deletions(-) diff -puN arch/x86/Kconfig~make-list_poison-less-deadly-v2 arch/x86/Kconfig --- a/arch/x86/Kconfig~make-list_poison-less-deadly-v2 +++ a/arch/x86/Kconfig @@ -1025,6 +1025,11 @@ config ARCH_MEMORY_PROBE def_bool X86_64 depends on MEMORY_HOTPLUG +config ILLEGAL_POINTER_VALUE + hex + default 0 if X86_32 + default 0x8888888800000000 if X86_64 + source "mm/Kconfig" config HIGHPTE diff -puN include/linux/poison.h~make-list_poison-less-deadly-v2 include/linux/poison.h --- a/include/linux/poison.h~make-list_poison-less-deadly-v2 +++ a/include/linux/poison.h @@ -1,14 +1,20 @@ #ifndef _LINUX_POISON_H #define _LINUX_POISON_H +#ifdef CONFIG_ILLEGAL_POINTER_VALUE +#define POISON_POINTER_DELTA CONFIG_ILLEGAL_POINTER_VALUE +#else +#define POISON_POINTER_DELTA 0L +#endif + /********** include/linux/list.h **********/ /* * 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) -#define LIST_POISON2 ((void *) 0x00200200) +#define LIST_POISON1 ((void *) 0x00100100 + POISON_POINTER_DELTA) +#define LIST_POISON2 ((void *) 0x00200200 + POISON_POINTER_DELTA) /********** include/linux/timer.h **********/ /* _ Patches currently in -mm which might be from avi@xxxxxxxxxxxx are origin.patch linux-next.patch dma-mapping-add-the-device-argument-to-dma_mapping_error.patch dma-mapping-x86-per-device-dma_mapping_ops-support.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html