[tip:core/urgent] stackprotector: Increase the per-task stack canary's random range from 32 bits to 64 bits on 64-bit platforms

tip-bot for Daniel Micay
2017-05-05T08:18:22Z

Commit-ID: 5ea30e4e58040cfd6434c2f33dc3ea76e2c15b05
Gitweb: http://git.kernel.org/tip/5ea30e4e58040cfd6434c2f33dc3ea76e2c15b05
Author: Daniel Micay <danielmicay@gmail.com>
AuthorDate: Thu, 4 May 2017 09:32:09 -0400
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 5 May 2017 08:05:13 +0200

stackprotector: Increase the per-task stack canary's random range from 32 bits to 64 bits on 64-bit platforms

The stack canary is an 'unsigned long' and should be fully initialized to
random data rather than only 32 bits of random data.

Signed-off-by: Daniel Micay <danielmicay@gmail.com>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Arjan van Ven <arjan@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-hardening@lists.openwall.com
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20170504133209.3053-1-danielmicay@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/fork.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/fork.c b/kernel/fork.c
index 3a4343c..d681f8f 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -536,7 +536,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
set_task_stack_end_magic(tsk);

#ifdef CONFIG_CC_STACKPROTECTOR
- tsk->stack_canary = get_random_int();
+ tsk->stack_canary = get_random_long();
#endif

/*