Re: [kernel-hardening] [PATCH 4.4 47/90] stackprotector: Increase the per-task stack canarys random range from 32 bits to 64 bits on 64-bit platforms
From: Jann Horn <jannh@google.com>
Date: 2017-06-12 15:50:08
Also in:
lkml
AFAICS get_random_long() doesn't exist in 4.4 (except in arch/x86/boot/compressed/aslr.c)? IIRC the same problem already occured with another kernel version? On Mon, Jun 12, 2017 at 5:25 PM, Greg Kroah-Hartman [off-list ref] wrote:
quoted hunk ↗ jump to hunk
4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daniel Micay <redacted> commit 5ea30e4e58040cfd6434c2f33dc3ea76e2c15b05 upstream. 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 <redacted> Acked-by: Arjan van de Ven <redacted> Acked-by: Rik van Riel <redacted> Acked-by: Kees Cook <redacted> Cc: Arjan van Ven <redacted> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <redacted> 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- kernel/fork.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)--- a/kernel/fork.c +++ b/kernel/fork.c@@ -368,7 +368,7 @@ static struct task_struct *dup_task_stru set_task_stack_end_magic(tsk); #ifdef CONFIG_CC_STACKPROTECTOR - tsk->stack_canary = get_random_int(); + tsk->stack_canary = get_random_long(); #endif /*