Re: [PATCH 3/3] x86: kernel base offset ASLR

[Kees Cook]

On Fri, Apr 5, 2013 at 1:43 PM, Borislav Petkov <bp@xxxxxxxxx> wrote:
> On Fri, Apr 05, 2013 at 01:19:39PM -0700, Julien Tinnes wrote:
>> I think it'd be perfectly ok for OOPS to print out the kernel base.
>
> Yeah, ok, this still would need some massaging of the oops output per
> script, but it shouldn't be a big problem.
>
> Also, you probably need to make clear in the oops itself that the
> addresses have been randomized. Or, is the mere presence of kernel base
> going to imply that?

There is already a hook in the patch that prints the offset:

+dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
+{
+       pr_emerg("Kernel Offset: 0x%lx\n",
+                (unsigned long)&_text - __START_KERNEL);
...
+       atomic_notifier_chain_register(&panic_notifier_list,
+                                       &kernel_offset_notifier);

But of course, this can get improved.

-Kees

--
Kees Cook
Chrome OS Security
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