Re: [RFC v1 3/4] x86, boot: Implement ASLR for kernel memory sections (x86_64)

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On April 21, 2016 6:30:24 AM PDT, Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> wrote:
>
>
>On 04/15/2016 06:03 PM, Thomas Garnier wrote:
>> +void __init kernel_randomize_memory(void)
>> +{
>> +	size_t i;
>> +	unsigned long addr = memory_rand_start;
>> +	unsigned long padding, rand, mem_tb;
>> +	struct rnd_state rnd_st;
>> +	unsigned long remain_padding = memory_rand_end - memory_rand_start;
>> +
>> +	if (!kaslr_enabled())
>> +		return;
>> +
>> +	/* Take the additional space when Xen is not active. */
>> +	if (!xen_domain())
>> +		page_offset_base -= __XEN_SPACE;
>
>This should be !xen_pv_domain(). Xen HVM guests are no different from 
>bare metal as far as address ranges are concerned. (Technically it's 
>probably !xen_pv_domain() && !xen_pvh_domain() but we can ignore PVH
>for 
>now since it is being replaced by an HVM-type guest)
>
>Having said that, I am not sure I understand why page_offset_base is 
>shifted. I thought 0xffff800000000000 - 0xffff87ffffffffff is not 
>supposed to be used by anyone, whether we are running under a
>hypervisor 
>or not.
>
>-boris

That range is reserved for the hypervisor use.
-- 
Sent from my Android device with K-9 Mail. Please excuse brevity and formatting.
--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Kernel Newbies]     [Security]     [Netfilter]     [Bugtraq]     [Linux FS]     [Yosemite Forum]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Video 4 Linux]     [Device Mapper]     [Linux Resources]

  Powered by Linux