Re: [PATCH] binfmt_elf: fix PIE load with randomization disabled

[Jiri Kosina]

On Mon, 9 Dec 2013, H.J. Lu wrote:

> Normally, a PIE executable has zero virtual address on the first PT_LOAD
> segment and kernel will load such executable at random address when
> randomization is enabled.  If randomization is disabled, kernel will load
> it at a fixed address.  But if a PIE executable has non-zero virtual
> address on the first PT_LOAD segment, kernel will load such executable
> at the non-zero virtual address when randomization is enabled. But when
> randomization is disabled, kernel ignores the non-zero virtual address
> at the non-zero virtual address when randomization is enabled. 

Hmm ... isn't actually this the thing that needs to be fixed instead? 

IOW, when randomization is enabled, is there a reason not to load on 
randomized address? (even if the first PT_LOAD segment has non-zero 
vaddr?)

> But when randomization is disabled, kernel ignores the non-zero virtual 
> address on the first PT_LOAD segment and loads it at the fixed address.  
> This patch makes kernel consistent by loading PIE executable with 
> non-zero virtual address at the non-zero virtual address, regardless if 
> randomization is enabled or disabled.

-- 
Jiri Kosina
SUSE Labs
--
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/