From: Andy Lutomirski <luto@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andy Lutomirsky <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Dave Hansen <dave.hansen@intel.com>,
Borislav Petkov <bpetkov@suse.de>,
Greg KH <gregkh@linuxfoundation.org>,
Kees Cook <keescook@google.com>, Hugh Dickins <hughd@google.com>,
Brian Gerst <brgerst@gmail.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Denys Vlasenko <dvlasenk@redhat.com>,
Rik van Riel <riel@redhat.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>,
David Laight <David.Laight@aculab.com>,
Eduardo Valentin <eduval@amazon.com>,
aliguori@amazon.com, Will Deacon <will.deacon@arm.com>,
Daniel Gruss <daniel.gruss@iaik.tugraz.at>,
Dave Hansen <dave.hansen@linux.intel.com>,
Ingo Molnar <mingo@kernel.org>,
moritz.lipp@iaik.tugraz.at,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Borislav Petkov <bp@alien8.de>,
michael.schwarz@iaik.tugraz.at,
richard.fellner@student.tugraz.at
Subject: Re: [patch 56/60] x86/mm/kpti: Disable native VSYSCALL
Date: Mon, 4 Dec 2017 14:33:31 -0800 [thread overview]
Message-ID: <CALCETrV8b0JB5DogXb1qj-7kEpioJhm13KSTYtDeJnQYvr+oQQ@mail.gmail.com> (raw)
In-Reply-To: <20171204150609.416845605@linutronix.de>
On Mon, Dec 4, 2017 at 6:08 AM, Thomas Gleixner <tglx@linutronix.de> wrote:
> From: Dave Hansen <dave.hansen@linux.intel.com>
>
> The KERNEL_PAGE_TABLE_ISOLATION code attempts to "poison" the user
> portion of the kernel page tables. It detects entries that it wants that it
> wants to poison in two ways:
>
> * Looking for addresses >= PAGE_OFFSET
>
> * Looking for entries without _PAGE_USER set
>
> But, to allow the _PAGE_USER check to work, it must never be set on
> init_mm entries, and an earlier patch in this series ensured that it
> will never be set.
>
> The VDSO is at a address >= PAGE_OFFSET and it is also mapped by init_mm.
> Because of the earlier, KERNEL_PAGE_TABLE_ISOLATION-enforced restriction,
> _PAGE_USER is never set which makes the VDSO unreadable to userspace.
>
> This makes the "NATIVE" case totally unusable since userspace can not even
> see the memory any more. Disable it whenever KERNEL_PAGE_TABLE_ISOLATION
> is enabled.
>
> Also add some help text about how KERNEL_PAGE_TABLE_ISOLATION might
> affect the emulation case as well.
>
I think my other suggestion may obsolete this patch.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-12-04 22:33 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20171204140706.296109558@linutronix.de>
2017-12-04 14:07 ` [patch 24/60] x86/paravirt: Dont patch flush_tlb_single Thomas Gleixner
2017-12-05 12:18 ` Juergen Gross
2017-12-04 14:07 ` [patch 28/60] x86/mm/kpti: Disable global pages if KERNEL_PAGE_TABLE_ISOLATION=y Thomas Gleixner
2017-12-05 14:34 ` Borislav Petkov
2017-12-04 14:07 ` [patch 29/60] x86/mm/kpti: Prepare the x86/entry assembly code for entry/exit CR3 switching Thomas Gleixner
2017-12-04 14:07 ` [patch 48/60] x86/mm: Move the CR3 construction functions to tlbflush.h Thomas Gleixner
2017-12-04 14:07 ` [patch 49/60] x86/mm: Remove hard-coded ASID limit checks Thomas Gleixner
2017-12-04 14:07 ` [patch 50/60] x86/mm: Put MMU to hardware ASID translation in one place Thomas Gleixner
2017-12-04 14:08 ` [patch 56/60] x86/mm/kpti: Disable native VSYSCALL Thomas Gleixner
2017-12-04 22:33 ` Andy Lutomirski [this message]
2017-12-04 14:08 ` [patch 57/60] x86/mm/kpti: Add Kconfig Thomas Gleixner
2017-12-04 16:54 ` Andy Lutomirski
2017-12-04 16:57 ` Thomas Gleixner
2017-12-05 9:34 ` Thomas Gleixner
2017-12-04 14:08 ` [patch 59/60] x86/mm/dump_pagetables: Check user space page table for WX pages Thomas Gleixner
2017-12-04 14:08 ` [patch 60/60] x86/mm/debug_pagetables: Allow dumping current pagetables Thomas Gleixner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CALCETrV8b0JB5DogXb1qj-7kEpioJhm13KSTYtDeJnQYvr+oQQ@mail.gmail.com \
--to=luto@kernel.org \
--cc=David.Laight@aculab.com \
--cc=aliguori@amazon.com \
--cc=boris.ostrovsky@oracle.com \
--cc=bp@alien8.de \
--cc=bpetkov@suse.de \
--cc=brgerst@gmail.com \
--cc=daniel.gruss@iaik.tugraz.at \
--cc=dave.hansen@intel.com \
--cc=dave.hansen@linux.intel.com \
--cc=dvlasenk@redhat.com \
--cc=eduval@amazon.com \
--cc=gregkh@linuxfoundation.org \
--cc=hughd@google.com \
--cc=jgross@suse.com \
--cc=jpoimboe@redhat.com \
--cc=keescook@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=michael.schwarz@iaik.tugraz.at \
--cc=mingo@kernel.org \
--cc=moritz.lipp@iaik.tugraz.at \
--cc=peterz@infradead.org \
--cc=richard.fellner@student.tugraz.at \
--cc=riel@redhat.com \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
--cc=will.deacon@arm.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox