New KASLR values in 'sysctl.conf' lead to errors

New KASLR values in 'sysctl.conf' lead to errors

[Matthias Fischer]

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Hi,

sorry, next one:

Commit
https://git.ipfire.org/?p=ipfire-2.x.git;a=commitdiff;h=ef21f3e49d2998eb4a223c05ef05f169ae99537a#patch1

"Changed sysctl values are:

vm.mmap_rnd_bits = 32 (default: 28)
vm.mmap_rnd_compat_bits = 16 (default: 8)"

After 'sysctl -p' I get:

***SNIP***
...
error: "Invalid argument" setting key "vm.mmap_rnd_bits"
error: "vm.mmap_rnd_compat_bits" is an unknown key
...
***SNAP***

Tested on Core 134/32bit, fresh install.

Can anyone confirm?

Best,
Matthias

Re: New KASLR values in 'sysctl.conf' lead to errors

[Peter Müller]

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Hello Matthias,

hm, the systctls are present on my 64 bit testing machine:

> [root(a)maverick ~]# sysctl -p
> - snip -
> vm.mmap_rnd_bits = 32
> vm.mmap_rnd_compat_bits = 16
> - snip -
> [root(a)maverick ~]# arch
> x86_64

Unfortunately I do not have 32 bit hardware at hand, and
the absence of those parameters surprises me.

@All: Does anybody have access to something more uncommon
like ARM SOCs? What about those?

@All, second: Does it make sense to ship different sysctl
values for different platforms?

Sorry for the inconvenience.

Thanks, and best regards,
Peter Müller


> Hi,
> 
> sorry, next one:
> 
> Commit
> https://git.ipfire.org/?p=ipfire-2.x.git;a=commitdiff;h=ef21f3e49d2998eb4a223c05ef05f169ae99537a#patch1
> 
> "Changed sysctl values are:
> 
> vm.mmap_rnd_bits = 32 (default: 28)
> vm.mmap_rnd_compat_bits = 16 (default: 8)"
> 
> After 'sysctl -p' I get:
> 
> ***SNIP***
> ...
> error: "Invalid argument" setting key "vm.mmap_rnd_bits"
> error: "vm.mmap_rnd_compat_bits" is an unknown key
> ...
> ***SNAP***
> 
> Tested on Core 134/32bit, fresh install.
> 
> Can anyone confirm?
> 
> Best,
> Matthias
> 

-- 
The road to Hades is easy to travel.
	-- Bion of Borysthenes

Re: New KASLR values in 'sysctl.conf' lead to errors

[Arne Fitzenreiter]

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Ths parameters are absent on all archs except x86_64 because they 
configure KPTI/KASLR.


On 2019-07-13 14:10, Matthias Fischer wrote:
> Hi,
> 
> sorry, next one:
> 
> Commit
> https://git.ipfire.org/?p=ipfire-2.x.git;a=commitdiff;h=ef21f3e49d2998eb4a223c05ef05f169ae99537a#patch1
> 
> "Changed sysctl values are:
> 
> vm.mmap_rnd_bits = 32 (default: 28)
> vm.mmap_rnd_compat_bits = 16 (default: 8)"
> 
> After 'sysctl -p' I get:
> 
> ***SNIP***
> ...
> error: "Invalid argument" setting key "vm.mmap_rnd_bits"
> error: "vm.mmap_rnd_compat_bits" is an unknown key
> ...
> ***SNAP***
> 
> Tested on Core 134/32bit, fresh install.
> 
> Can anyone confirm?
> 
> Best,
> Matthias

Re: New KASLR values in 'sysctl.conf' lead to errors

[Michael Tremer]

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Hi,

Arne, would you prefer an extra file for x86_64, or an initscript that checks the architecture and then calls sysctl?

-Michael

> On 17 Jul 2019, at 16:40, Arne Fitzenreiter <Arne.Fitzenreiter(a)ipfire.org> wrote:
> 
> Ths parameters are absent on all archs except x86_64 because they configure KPTI/KASLR.
> 
> 
> On 2019-07-13 14:10, Matthias Fischer wrote:
>> Hi,
>> sorry, next one:
>> Commit
>> https://git.ipfire.org/?p=ipfire-2.x.git;a=commitdiff;h=ef21f3e49d2998eb4a223c05ef05f169ae99537a#patch1
>> "Changed sysctl values are:
>> vm.mmap_rnd_bits = 32 (default: 28)
>> vm.mmap_rnd_compat_bits = 16 (default: 8)"
>> After 'sysctl -p' I get:
>> ***SNIP***
>> ...
>> error: "Invalid argument" setting key "vm.mmap_rnd_bits"
>> error: "vm.mmap_rnd_compat_bits" is an unknown key
>> ...
>> ***SNAP***
>> Tested on Core 134/32bit, fresh install.
>> Can anyone confirm?
>> Best,
>> Matthias