Re: [PATCH 6/6] x86: kaslr: report kernel offset on panic
From: Borislav Petkov
Date: Fri Apr 26 2013 - 18:13:14 EST
On Fri, Apr 26, 2013 at 12:03:25PM -0700, Kees Cook wrote:
> When the system panics, include the kernel offset in the report to assist
> in debugging.
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> arch/x86/kernel/setup.c | 24 ++++++++++++++++++++++++
> 1 file changed, 24 insertions(+)
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index fae9134..95a33b1 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -830,6 +830,18 @@ static void __init trim_low_memory_range(void)
> + * Dump out kernel offset information on panic.
> + */
> +static int
> +dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
> + pr_emerg("Kernel Offset: 0x%lx\n",
> + (unsigned long)&_text - __START_KERNEL);
So what's wrong with subtracting the offset from the function addresses
on the stack so that traces can show the addresses as they are in
vmlinux, completely agnostic of any randomization?
Sent from a fat crate under my desk. Formatting is fine.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/