[PATCH] Add the canary field to the PDA area and the task struct

This patch adds the per thread cookie field to the task struct and the PDA.
Also it makes sure that the PDA value gets the new cookie value at context
switch, and that a new task gets a new cookie at task creation time.

Signed-off-by: Arjan van Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andi Kleen <ak@suse.de>
CC: Andi Kleen <ak@suse.de>

1 files changed, 5 insertions, 0 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index f9b014e3e700..a0dad84567c9 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -45,6 +45,7 @@
 #include <linux/cn_proc.h>
 #include <linux/delayacct.h>
 #include <linux/taskstats_kern.h>
+#include <linux/random.h>
 
 #include <asm/pgtable.h>
 #include <asm/pgalloc.h>
@@ -175,6 +176,10 @@ static struct task_struct *dup_task_struct(struct task_struct *orig)
         tsk->thread_info = ti;
         setup_thread_stack(tsk, orig);
 
+#ifdef CONFIG_CC_STACKPROTECTOR
+        tsk->stack_canary = get_random_int();
+#endif
+
         /* One for us, one for whoever does the "release_task()" (usually parent) */
         atomic_set(&tsk->usage,2);
         atomic_set(&tsk->fs_excl, 0);