On Thu, 3 Dec 2020, Florian Weimer wrote:
> My knowledge of probability theory is quite limited, so I have to rely
> on simulations. But I think you would see a 40 GiB gap somewhere for a
> 47-bit address space with 32K allocations, most of the time. Which is
> not too bad.
This is very close
On Thu, Dec 03, 2020 at 09:42:54AM -0800, Andy Lutomirski wrote:
> I suspect that something much more clever could be done in which the heap is
> divided up into a few independently randomized sections and heap pages are
> randomized within the sections might do much better. There should
> On Dec 3, 2020, at 9:29 AM, Florian Weimer wrote:
>
> * Andy Lutomirski:
>
>> If you want a 4GB allocation to succeed, you can only divide the
>> address space into 32k fragments. Or, a little more precisely, if you
>> want a randomly selected 4GB region to be empty, any other allocation
* Andy Lutomirski:
> If you want a 4GB allocation to succeed, you can only divide the
> address space into 32k fragments. Or, a little more precisely, if you
> want a randomly selected 4GB region to be empty, any other allocation
> has a 1/32k chance of being in the way. (Rough numbers — I’m
> On Dec 3, 2020, at 4:06 AM, Topi Miettinen wrote:
>
> On 3.12.2020 11.47, Florian Weimer wrote:
>> * Topi Miettinen:
>>> +3 Additionally enable full randomization of memory mappings created
>>> +with mmap(NULL, ...). With 2, the base of the VMA used for such
>>> +mappings is
On 3.12.2020 11.47, Florian Weimer wrote:
* Topi Miettinen:
+3 Additionally enable full randomization of memory mappings created
+with mmap(NULL, ...). With 2, the base of the VMA used for such
+mappings is random, but the mappings are created in predictable
+places within the
* Topi Miettinen:
> +3 Additionally enable full randomization of memory mappings created
> +with mmap(NULL, ...). With 2, the base of the VMA used for such
> +mappings is random, but the mappings are created in predictable
> +places within the VMA and in sequential order. With 3,
On 30.11.2020 19.57, Andy Lutomirski wrote:
On Sun, Nov 29, 2020 at 1:20 PM Topi Miettinen wrote:
Writing a new value of 3 to /proc/sys/kernel/randomize_va_space
enables full randomization of memory mappings created with mmap(NULL,
...). With 2, the base of the VMA used for such mappings is
On Sun, Nov 29, 2020 at 1:20 PM Topi Miettinen wrote:
>
> Writing a new value of 3 to /proc/sys/kernel/randomize_va_space
> enables full randomization of memory mappings created with mmap(NULL,
> ...). With 2, the base of the VMA used for such mappings is random,
> but the mappings are created in
Hi Topi,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on aae5ab854e38151e69f261dbf0e3b7e396403178]
url:
https://github.com/0day-ci/linux/commits/Topi-Miettinen/mm-Optional-full-ASLR-for-mmap-mremap-vdso-and-stack/20201130-051703
base:
Writing a new value of 3 to /proc/sys/kernel/randomize_va_space
enables full randomization of memory mappings created with mmap(NULL,
...). With 2, the base of the VMA used for such mappings is random,
but the mappings are created in predictable places within the VMA and
in sequential order. With
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