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

Vivek Goyal
2011-05-26T20:35:23Z

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.

Thanks
Vivek