aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--arch/x86/Kconfig5
-rw-r--r--include/linux/poison.h16
2 files changed, 19 insertions, 2 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 6bf1f1ac478..cbcbfdee3ee 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1247,6 +1247,11 @@ config ARCH_MEMORY_PROBE
def_bool X86_64
depends on MEMORY_HOTPLUG
+config ILLEGAL_POINTER_VALUE
+ hex
+ default 0 if X86_32
+ default 0xdead000000000000 if X86_64
+
source "mm/Kconfig"
config HIGHPTE
diff --git a/include/linux/poison.h b/include/linux/poison.h
index 7fc194aef8c..2110a81c5e2 100644
--- a/include/linux/poison.h
+++ b/include/linux/poison.h
@@ -2,13 +2,25 @@
#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)
-#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 **********/
/*