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From: Peter Zijlstra <peterz@infradead.org>
To: Alison Schofield <alison.schofield@intel.com>
Cc: dhowells@redhat.com, tglx@linutronix.de, jmorris@namei.org,
	mingo@redhat.com, hpa@zytor.com, bp@alien8.de, luto@kernel.org,
	kirill.shutemov@linux.intel.com, dave.hansen@intel.com,
	kai.huang@intel.com, jun.nakajima@intel.com,
	dan.j.williams@intel.com, jarkko.sakkinen@intel.com,
	keyrings@vger.kernel.org, linux-security-module@vger.kernel.org,
	linux-mm@kvack.org, x86@kernel.org
Subject: Re: [RFC v2 09/13] mm: Restrict memory encryption to anonymous VMA's
Date: Tue, 4 Dec 2018 10:10:44 +0100
Message-ID: <20181204091044.GP11614@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <0b294e74f06a0d6bee51efcd7b0eb1f20b00babe.1543903910.git.alison.schofield@intel.com>

On Mon, Dec 03, 2018 at 11:39:56PM -0800, Alison Schofield wrote:
> Memory encryption is only supported for mappings that are ANONYMOUS.
> Test the entire range of VMA's in an encrypt_mprotect() request to
> make sure they all meet that requirement before encrypting any.
> 
> The encrypt_mprotect syscall will return -EINVAL and will not encrypt
> any VMA's if this check fails.
> 
> Signed-off-by: Alison Schofield <alison.schofield@intel.com>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

That SoB doesn't make sense; per the From you wrote the patch and signed
off on it, wth is Kirill's SoB doing there?

> diff --git a/mm/mprotect.c b/mm/mprotect.c
> index ad8127dc9aac..f1c009409134 100644
> --- a/mm/mprotect.c
> +++ b/mm/mprotect.c
> @@ -345,6 +345,24 @@ static int prot_none_walk(struct vm_area_struct *vma, unsigned long start,
>  	return walk_page_range(start, end, &prot_none_walk);
>  }
>  
> +/*
> + * Encrypted mprotect is only supported on anonymous mappings.
> + * All VMA's in the requested range must be anonymous. If this
> + * test fails on any single VMA, the entire mprotect request fails.
> + */
> +bool mem_supports_encryption(struct vm_area_struct *vma, unsigned long end)

That's a 'weird' interface and cannot do what the comment says it should
do.

> +{
> +	struct vm_area_struct *test_vma = vma;

That variable is utterly pointless.

> +	do {
> +		if (!vma_is_anonymous(test_vma))
> +			return false;
> +
> +		test_vma = test_vma->vm_next;
> +	} while (test_vma && test_vma->vm_start < end);
> +	return true;
> +}

  reply index

Thread overview: 91+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-04  7:39 [RFC v2 00/13] Multi-Key Total Memory Encryption API (MKTME) Alison Schofield
2018-12-04  7:39 ` [RFC v2 01/13] x86/mktme: Document the MKTME APIs Alison Schofield
2018-12-05 18:11   ` Andy Lutomirski
2018-12-05 19:22     ` Alison Schofield
2018-12-05 23:35       ` Andy Lutomirski
2018-12-06  8:04   ` Sakkinen, Jarkko
2018-12-04  7:39 ` [RFC v2 02/13] mm: Generalize the mprotect implementation to support extensions Alison Schofield
2018-12-06  8:08   ` Sakkinen, Jarkko
2018-12-04  7:39 ` [RFC v2 03/13] syscall/x86: Wire up a new system call for memory encryption keys Alison Schofield
2018-12-04  7:39 ` [RFC v2 04/13] x86/mm: Add helper functions for MKTME " Alison Schofield
2018-12-04  9:14   ` Peter Zijlstra
2018-12-05  5:49     ` Alison Schofield
2018-12-04 15:35   ` Andy Lutomirski
2018-12-05  5:52     ` Alison Schofield
2018-12-06  8:31   ` Sakkinen, Jarkko
2018-12-04  7:39 ` [RFC v2 05/13] x86/mm: Set KeyIDs in encrypted VMAs Alison Schofield
2018-12-06  8:37   ` Sakkinen, Jarkko
2018-12-04  7:39 ` [RFC v2 06/13] mm: Add the encrypt_mprotect() system call Alison Schofield
2018-12-06  8:38   ` Sakkinen, Jarkko
2018-12-04  7:39 ` [RFC v2 07/13] x86/mm: Add helpers for reference counting encrypted VMAs Alison Schofield
2018-12-04  8:58   ` Peter Zijlstra
2018-12-05  5:28     ` Alison Schofield
2018-12-04  7:39 ` [RFC v2 08/13] mm: Use reference counting for " Alison Schofield
2018-12-04  7:39 ` [RFC v2 09/13] mm: Restrict memory encryption to anonymous VMA's Alison Schofield
2018-12-04  9:10   ` Peter Zijlstra [this message]
2018-12-05  5:30     ` Alison Schofield
2018-12-05  9:07       ` Peter Zijlstra
2018-12-04  7:39 ` [RFC v2 10/13] keys/mktme: Add the MKTME Key Service type for memory encryption Alison Schofield
2018-12-06  8:51   ` Sakkinen, Jarkko
2018-12-06  8:54     ` Sakkinen, Jarkko
2018-12-06 15:11     ` Dave Hansen
2018-12-06 22:56       ` Sakkinen, Jarkko
2018-12-04  7:39 ` [RFC v2 11/13] keys/mktme: Program memory encryption keys on a system wide basis Alison Schofield
2018-12-04  9:21   ` Peter Zijlstra
2018-12-04  9:50     ` Kirill A. Shutemov
2018-12-05  5:44       ` Alison Schofield
2018-12-05  5:43     ` Alison Schofield
2018-12-05  9:10       ` Peter Zijlstra
2018-12-05 17:26         ` Alison Schofield
2018-12-04  7:39 ` [RFC v2 12/13] keys/mktme: Save MKTME data if kernel cmdline parameter allows Alison Schofield
2018-12-04  9:22   ` Peter Zijlstra
2018-12-07  2:14   ` Huang, Kai
2018-12-07  3:42     ` Alison Schofield
2018-12-07  6:39     ` Jarkko Sakkinen
2018-12-07  6:45       ` Jarkko Sakkinen
2018-12-07 11:47     ` Kirill A. Shutemov
2018-12-04  7:40 ` [RFC v2 13/13] keys/mktme: Support CPU Hotplug for MKTME keys Alison Schofield
2018-12-04  9:28   ` Peter Zijlstra
2018-12-05  5:32     ` Alison Schofield
2018-12-04  9:31   ` Peter Zijlstra
2018-12-05  5:36     ` Alison Schofield
2018-12-04  9:25 ` [RFC v2 00/13] Multi-Key Total Memory Encryption API (MKTME) Peter Zijlstra
2018-12-04  9:46   ` Kirill A. Shutemov
2018-12-05 20:32     ` Sakkinen, Jarkko
2018-12-06 11:22       ` Kirill A. Shutemov
2018-12-06 14:59         ` Dave Hansen
2018-12-07 10:12           ` Huang, Kai
2018-12-06 21:23         ` Sakkinen, Jarkko
2018-12-07 11:54           ` Kirill A. Shutemov
2018-12-04 19:19 ` Andy Lutomirski
2018-12-04 20:00   ` Andy Lutomirski
2018-12-04 20:32     ` Dave Hansen
2018-12-05 22:19   ` Sakkinen, Jarkko
2018-12-07  2:05     ` Huang, Kai
2018-12-07  6:48       ` Jarkko Sakkinen
2018-12-07 11:57     ` Kirill A. Shutemov
2018-12-07 21:59       ` Sakkinen, Jarkko
2018-12-07 23:45         ` Sakkinen, Jarkko
2018-12-07 23:48           ` Andy Lutomirski
2018-12-08  1:33           ` Huang, Kai
2018-12-08  3:53             ` Sakkinen, Jarkko
2018-12-12 15:31           ` Sakkinen, Jarkko
2018-12-12 16:29             ` Andy Lutomirski
2018-12-12 16:43               ` Sakkinen, Jarkko
2018-12-12 23:27                 ` Huang, Kai
2018-12-13  5:49                   ` Sakkinen, Jarkko
2018-12-13  5:52                     ` Sakkinen, Jarkko
2018-12-12 23:24               ` Huang, Kai
2018-12-07 23:35       ` Eric Rannaud
2018-12-05 23:49   ` Dave Hansen
2018-12-06  1:09     ` Andy Lutomirski
2018-12-06  1:25       ` Dan Williams
2018-12-06 15:39       ` Dave Hansen
2018-12-06 19:10         ` Andy Lutomirski
2018-12-06 19:31           ` Dave Hansen
2018-12-07  1:55       ` Huang, Kai
2018-12-07  4:23         ` Dave Hansen
2018-12-07 23:53         ` Andy Lutomirski
2018-12-08  1:11           ` Dave Hansen
2018-12-08  2:07           ` Huang, Kai
2018-12-05 20:30 ` Sakkinen, Jarkko

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