From: Nadav Amit <namit@vmware.com>
To: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"aarcange@redhat.com" <aarcange@redhat.com>,
"luto@kernel.org" <luto@kernel.org>,
"torvalds@linux-foundation.org" <torvalds@linux-foundation.org>,
"keescook@google.com" <keescook@google.com>,
"hughd@google.com" <hughd@google.com>,
"jgross@suse.com" <jgross@suse.com>,
"x86@kernel.org" <x86@kernel.org>
Subject: Re: [RFC][PATCH 04/10] x86/espfix: use kernel-default PTE mask
Date: Thu, 22 Feb 2018 21:27:31 +0000 [thread overview]
Message-ID: <93613F56-C778-4EA0-8945-A0B8ABC1A5FD@vmware.com> (raw)
In-Reply-To: <20180222203658.80705136@viggo.jf.intel.com>
Dave Hansen <dave.hansen@linux.intel.com> wrote:
>
> From: Dave Hansen <dave.hansen@linux.intel.com>
>
> In creating its page tables, the espfix code masks its PGTABLE_PROT
> value with the supported mask: __supported_pte_mask. This ensures
> that unsupported bits are not set in the final PTE. But, it also
> sets _PAGE_GLOBAL which we do not want for PTE. Use
> __default_kernel_pte_mask instead which clears _PAGE_GLOBAL for PTI.
Can you please explain what is your concern? Exposing more gadgets for
speculative ROP attacks?
Or is it a general rule of not exposing any kernel code &data more than
absolutely necessary?
next prev parent reply other threads:[~2018-02-22 21:27 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-22 20:36 [RFC][PATCH 00/10] Use global pages with PTI Dave Hansen
2018-02-22 20:36 ` [RFC][PATCH 01/10] x86/mm: factor out pageattr _PAGE_GLOBAL setting Dave Hansen
2018-02-22 20:36 ` [RFC][PATCH 02/10] x86/mm: undo double _PAGE_PSE clearing Dave Hansen
2018-02-22 20:36 ` [RFC][PATCH 03/10] x86/mm: introduce "default" kernel PTE mask Dave Hansen
2018-02-22 22:21 ` Nadav Amit
2018-02-22 22:26 ` Dave Hansen
2018-02-22 23:11 ` Tom Lendacky
2018-02-23 23:46 ` Dave Hansen
2018-02-22 20:36 ` [RFC][PATCH 04/10] x86/espfix: use kernel-default " Dave Hansen
2018-02-22 21:27 ` Nadav Amit [this message]
2018-02-22 21:30 ` Dave Hansen
2018-02-22 21:59 ` Andy Lutomirski
2018-02-22 22:05 ` Dave Hansen
2018-02-22 20:37 ` [RFC][PATCH 05/10] x86/mm: do not auto-massage page protections Dave Hansen
2018-02-22 21:46 ` Nadav Amit
2018-02-22 21:52 ` Dave Hansen
2018-02-22 20:37 ` [RFC][PATCH 06/10] x86/mm: remove extra filtering in pageattr code Dave Hansen
2018-02-22 20:37 ` [RFC][PATCH 07/10] x86/mm: comment _PAGE_GLOBAL mystery Dave Hansen
2018-02-22 20:37 ` [RFC][PATCH 08/10] x86/mm: do not forbid _PAGE_RW before init for __ro_after_init Dave Hansen
2018-02-22 20:53 ` Kees Cook
2018-02-22 20:37 ` [RFC][PATCH 09/10] x86/pti: enable global pages for shared areas Dave Hansen
2018-02-22 20:37 ` [RFC][PATCH 10/10] x86/pti: clear _PAGE_GLOBAL for kernel image Dave Hansen
2018-02-22 21:52 ` [RFC][PATCH 00/10] Use global pages with PTI Linus Torvalds
2018-02-24 1:49 ` Dave Hansen
2018-02-24 4:20 ` Linus Torvalds
2018-02-24 4:34 ` [RFC][PATCH 00/10] Use global pages with PTI - Truth about the white man thetruthbeforeus
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