From: Nikolay Borisov <nik.borisov@suse.com>
To: David Laight <David.Laight@ACULAB.COM>,
"x86@kernel.org" <x86@kernel.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"mhocko@suse.com" <mhocko@suse.com>,
"jslaby@suse.cz" <jslaby@suse.cz>
Subject: Re: [PATCH v2 0/4] Make IA32_EMULATION boot time overridable
Date: Sun, 11 Jun 2023 11:19:19 +0300 [thread overview]
Message-ID: <95a3bf1b-96cf-5341-e3e1-828fd4210ce1@suse.com> (raw)
In-Reply-To: <930ebd9ac94843129781ec208a0dd69f@AcuMS.aculab.com>
On 11.06.23 г. 0:46 ч., David Laight wrote:
> From: Nikolay Borisov
>> Sent: 09 June 2023 12:13
>>
>> Here's the 2nd version of the patch which aims to make IA32_EMULATION essentially
>> a boot time option. The changes in this posting are:
>
> Does it make any sense to be able to enable/disable it at run-time
> (through a sysctl).
I'd say now, because then we are losing consistency, that is if the
sysctl is off, then some 32bit process is being run, then you flip it
back to on and suddenly this process dies (if it's using syscalls that is).
With a boot time switch we'll ensure that no 32bit process can be
loaded, which at least can give the sysadmin some assurance that the
machine is 32bit clean. Am I missing something?
> Perhaps only if enabled at boot - where it can be a 'soft disable'
> even though the cpu is initialised to allow the 32bit system calls.
>
> Remember, if you are root (and the system isn't hard locked down)
Well, if you are root then every bet's off?
> it is pretty easy to change a global boolean variable.
> So it doesn't really affect the attack surface.
>
> David
>
> -
> Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
> Registration No: 1397386 (Wales)
>
prev parent reply other threads:[~2023-06-11 8:19 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-09 11:13 [PATCH v2 0/4] Make IA32_EMULATION boot time overridable Nikolay Borisov
2023-06-09 11:13 ` [PATCH v2 1/4] x86: Introduce CONFIG_IA32_EMULATION_DEFAULT_DISABLED Kconfig option Nikolay Borisov
2023-06-09 15:06 ` Thomas Gleixner
2023-06-10 2:21 ` Randy Dunlap
2023-06-09 11:13 ` [PATCH v2 2/4] x86/entry: Rename ignore_sysret and compile it unconditionally Nikolay Borisov
2023-06-09 15:08 ` Thomas Gleixner
2023-06-09 11:13 ` [PATCH v2 3/4] x86/entry: Disable IA32 syscall if ia32_disabled is true Nikolay Borisov
2023-06-09 15:22 ` Thomas Gleixner
2023-06-09 16:03 ` Nikolay Borisov
2023-06-09 16:13 ` Nikolay Borisov
2023-06-10 11:26 ` Thomas Gleixner
2023-06-09 11:13 ` [PATCH v2 4/4] x86: Disable laoding 32bit processes " Nikolay Borisov
2023-06-09 15:26 ` Thomas Gleixner
2023-06-09 16:45 ` Brian Gerst
2023-06-10 21:46 ` [PATCH v2 0/4] Make IA32_EMULATION boot time overridable David Laight
2023-06-11 8:19 ` Nikolay Borisov [this message]
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