Re: [PATCH 1/3] vmalloc: Add __vmalloc_node_try_addr function

From: Randy Dunlap <rdunlap@infradead.org>
To: Kees Cook <keescook@chromium.org>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	X86 ML <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>,
	Linux-MM <linux-mm@kvack.org>,
	Kernel Hardening <kernel-hardening@lists.openwall.com>,
	kristen Accardi <kristen.c.accardi@intel.com>,
	Dave Hansen <dave.hansen@intel.com>,
	"Van De Ven, Arjan" <arjan.van.de.ven@intel.com>
Subject: Re: [PATCH 1/3] vmalloc: Add __vmalloc_node_try_addr function
Date: Wed, 20 Jun 2018 16:16:42 -0700	[thread overview]
Message-ID: <c26266cf-1f90-2688-d131-501dbaf9460a@infradead.org> (raw)
In-Reply-To: <CAGXu5j+TpZict=pSenHQ+_6V2fgoDrAGiB8sCd6bk-tb_Ec0zw@mail.gmail.com>

On 06/20/2018 04:05 PM, Kees Cook wrote:
> On Wed, Jun 20, 2018 at 3:44 PM, Randy Dunlap <rdunlap@infradead.org> wrote:
>> On 06/20/2018 03:35 PM, Kees Cook wrote:
>>> On Wed, Jun 20, 2018 at 3:16 PM, Randy Dunlap <rdunlap@infradead.org> wrote:
>>>> On 06/20/2018 03:09 PM, Rick Edgecombe wrote:
>>>>> +void *__vmalloc_node_try_addr(unsigned long addr, unsigned long size,
>>>>> +                     gfp_t gfp_mask, pgprot_t prot, unsigned long vm_flags,
>>>>> +                     int node, const void *caller)
>>>>> +{
>>>>
>>>> so this isn't optional, eh?  You are going to force it on people because?
>>>
>>> RANDOMIZE_BASE isn't optional either. :) This improves the module
>>> address entropy with (what seems to be) no down-side, so yeah, I think
>>> it should be non-optional. :)
>>
>> In what kernel tree is RANDOMIZE_BASE not optional?
> 
> Oh, sorry, I misspoke: on by default. It _is_ possible to turn it off.
> 
> But patch #2 does check for RANDOMIZE_BASE, so it should work as expected, yes?
> 
> Or did you want even this helper function to be compiled out without it?

Thanks, I missed it.  :(

Looks fine.

-- 
~Randy