Re: [RFC][PATCH] Randomize kernel base address on boot

Vivek Goyal
2011-05-26T20:41:16Z

On Thu, May 26, 2011 at 04:35:02PM -0400, Vivek Goyal wrote:
> On Tue, May 24, 2011 at 04:31:45PM -0400, Dan Rosenberg wrote:
> > This introduces CONFIG_RANDOMIZE_BASE, which randomizes the address at
> > which the kernel is decompressed at boot as a security feature that
> > deters exploit attempts relying on knowledge of the location of kernel
> > internals. The default values of the kptr_restrict and dmesg_restrict
> > sysctls are set to (1) when this is enabled, since hiding kernel
> > pointers is necessary to preserve the secrecy of the randomized base
> > address.
>
> What happens to /proc/iomem interface which gives us the physical memory
> location where kernel is loaded. kexec-tools relies on that interface
> heavily so we can not take it away. And if we can not take it away then
> I think somebody should be easibly be able to calculate this randomized
> base address.

Resending this mail as in last message I got the email address of Dan
wrong and mail bounced. Sorry about that.

Thanks
Vivek