From: Linus Torvalds <torvalds@linux-foundation.org>
To: Andy Lutomirski <luto@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>,
Luis Henriques <lhenriques@suse.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-arch <linux-arch@vger.kernel.org>,
Kernel Hardening <kernel-hardening@lists.openwall.com>,
Greg KH <gregkh@linuxfoundation.org>, X86 ML <x86@kernel.org>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Andrew Morton <akpm@linux-foundation.org>,
Alan Cox <alan@linux.intel.com>
Subject: Re: [PATCH v4 07/10] x86: narrow out of bounds syscalls to sys_read under speculation
Date: Tue, 6 Feb 2018 12:58:27 -0800 [thread overview]
Message-ID: <CA+55aFy2-OMMCatHTXL7wfP7H=4CEKv4Y_pRvfeEOCwxriDP4Q@mail.gmail.com> (raw)
In-Reply-To: <CALCETrXV3rHb7Z8iaoieAJ5hRY0+UT7eTknxe4-FiOoke9XoGg@mail.gmail.com>
On Tue, Feb 6, 2018 at 12:49 PM, Andy Lutomirski <luto@kernel.org> wrote:
>
> Can you use @cc to make an asm statement that outputs both the masked
> array index and the "if" condition? I can never remember the syntax,
> but something like:
Yes. Although I'd actually suggest just using an "asm goto" if we
really want to optimize this. Give the "index_mask_nospec()" a third
argument that is the label to jump to for overflow.
Then you can just decide how to implement it best for any particular
architecture (and compiler limitation).
Linus
next prev parent reply other threads:[~2018-02-06 20:58 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-19 0:01 [PATCH v4 00/10] prevent bounds-check bypass via speculative execution Dan Williams
2018-01-19 0:01 ` Dan Williams
2018-01-19 0:01 ` [PATCH v4 01/10] Documentation: document array_ptr Dan Williams
2018-01-19 0:01 ` [PATCH v4 02/10] asm/nospec, array_ptr: sanitize speculative array de-references Dan Williams
2018-01-19 0:01 ` Dan Williams
2018-01-19 10:20 ` [kernel-hardening] " Jann Horn
2018-01-19 17:48 ` Adam Sampson
2018-01-19 17:48 ` Adam Sampson
2018-01-19 18:12 ` Dan Williams
2018-01-19 18:18 ` Will Deacon
2018-01-19 18:18 ` [kernel-hardening] " Will Deacon
2018-01-19 18:26 ` Dan Williams
2018-01-19 18:18 ` Linus Torvalds
2018-01-19 18:18 ` [kernel-hardening] " Linus Torvalds
2018-01-19 20:55 ` Dan Williams
2018-01-25 7:09 ` Cyril Novikov
2018-01-25 7:09 ` Cyril Novikov
2018-01-25 22:37 ` Dan Williams
2018-01-25 22:37 ` Dan Williams
2018-01-19 0:01 ` [PATCH v4 03/10] x86: implement array_ptr_mask() Dan Williams
2018-01-19 0:01 ` [PATCH v4 04/10] x86: introduce __uaccess_begin_nospec and ifence Dan Williams
2018-01-19 0:02 ` [PATCH v4 05/10] x86, __get_user: use __uaccess_begin_nospec Dan Williams
2018-01-19 0:02 ` Dan Williams
2018-01-19 0:02 ` [PATCH v4 06/10] x86, get_user: use pointer masking to limit speculation Dan Williams
2018-01-19 0:02 ` [PATCH v4 07/10] x86: narrow out of bounds syscalls to sys_read under speculation Dan Williams
2018-01-24 14:40 ` Jiri Slaby
2018-02-06 19:29 ` Luis Henriques
2018-02-06 19:48 ` Dan Williams
2018-02-06 19:48 ` Dan Williams
2018-02-06 20:26 ` Linus Torvalds
2018-02-06 20:26 ` Linus Torvalds
2018-02-06 20:37 ` Dan Williams
2018-02-06 20:42 ` Linus Torvalds
2018-02-06 20:42 ` Linus Torvalds
2018-02-06 20:43 ` Linus Torvalds
2018-02-06 20:43 ` Linus Torvalds
2018-02-06 20:49 ` Andy Lutomirski
2018-02-06 20:49 ` Andy Lutomirski
2018-02-06 20:58 ` Linus Torvalds [this message]
2018-02-06 20:58 ` Linus Torvalds
2018-02-06 21:37 ` Dan Williams
2018-02-06 22:52 ` Linus Torvalds
2018-02-06 22:52 ` Linus Torvalds
2018-02-07 0:33 ` Dan Williams
2018-02-07 1:23 ` Linus Torvalds
2018-02-06 22:51 ` Luis Henriques
2018-02-06 22:51 ` Luis Henriques
2018-01-19 0:02 ` [PATCH v4 08/10] vfs, fdtable: prevent bounds-check bypass via speculative execution Dan Williams
2018-01-19 0:02 ` Dan Williams
2018-01-19 0:02 ` [PATCH v4 09/10] kvm, x86: fix spectre-v1 mitigation Dan Williams
2018-01-19 0:02 ` Dan Williams
2018-01-19 8:42 ` Paolo Bonzini
2018-01-19 8:42 ` Paolo Bonzini
[not found] ` <151632009605.21271.11304291057104672116.stgit-p8uTFz9XbKj2zm6wflaqv1nYeNYlB/vhral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2018-01-19 0:02 ` [PATCH v4 10/10] nl80211: sanitize array index in parse_txq_params Dan Williams
2018-01-19 0:02 ` Dan Williams
2018-01-21 10:37 ` Johannes Berg
2018-01-20 6:58 ` [PATCH v4 00/10] prevent bounds-check bypass via speculative execution Dan Williams
2018-01-20 6:58 ` Dan Williams
2018-01-20 16:56 ` Alexei Starovoitov
2018-01-20 16:56 ` Alexei Starovoitov
2018-01-20 17:07 ` Alexei Starovoitov
2018-01-20 17:07 ` Alexei Starovoitov
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