From: Florian Weimer <fweimer@redhat.com>
To: Andy Lutomirski <luto@kernel.org>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>, X86 ML <x86@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
"open list\:DOCUMENTATION" <linux-doc@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>,
linux-arch <linux-arch@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>,
Arnd Bergmann <arnd@arndb.de>,
Balbir Singh <bsingharora@gmail.com>,
Borislav Petkov <bp@alien8.de>,
Cyrill Gorcunov <gorcunov@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Eugene Syromiatnikov <esyr@redhat.com>,
"H.J. Lu" <hjl.tools@gmail.com>, Jann Horn <jannh@google.com>,
Jonathan Corbet <corbet@lwn.net>,
Kees Cook <keescook@chromium.org>,
Mike Kravetz <mike.kravetz@oracle.com>,
Nadav Amit <nadav.amit@gmail.com>,
Oleg Nesterov <oleg@redhat.com>, Pavel Machek <pavel@ucw.cz>,
Peter Zijlstra <peterz@infradead.org>,
Randy Dunlap <rdunlap@infradead.org>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Vedvyas Shanbhogue <vedvyas.shanbhogue@intel.com>,
Dave Martin <Dave.Martin@arm.com>,
Weijiang Yang <weijiang.yang@intel.com>
Subject: Re: [PATCH v11 9/9] x86: Disallow vsyscall emulation when CET is enabled
Date: Tue, 25 Aug 2020 11:14:37 +0200 [thread overview]
Message-ID: <87pn7f9jeq.fsf@oldenburg2.str.redhat.com> (raw)
In-Reply-To: <CALCETrVXwUDu2m-XEd-_J03L=sricM4cMxQYVkdGRWZDjmMB2g@mail.gmail.com> (Andy Lutomirski's message of "Mon, 24 Aug 2020 17:32:35 -0700")
* Andy Lutomirski:
> On Mon, Aug 24, 2020 at 5:30 PM Yu-cheng Yu <yu-cheng.yu@intel.com> wrote:
>>
>> From: "H.J. Lu" <hjl.tools@gmail.com>
>>
>> Emulation of the legacy vsyscall page is required by some programs built
>> before 2013. Newer programs after 2013 don't use it. Disallow vsyscall
>> emulation when Control-flow Enforcement (CET) is enabled to enhance
>> security.
>
> NAK.
>
> By all means disable execute emulation if CET-IBT is enabled at the
> time emulation is attempted, and maybe even disable the vsyscall page
> entirely if you can magically tell that CET-IBT will be enabled when a
> process starts, but you don't get to just disable it outright on a
> CET-enabled kernel.
Yeah, we definitely would have to revert/avoid this downstream. People
definitely want to run glibc-2.12-era workloads on current kernels.
Thanks for catching it.
Florian
next prev parent reply other threads:[~2020-08-25 9:15 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-25 0:26 [PATCH v11 0/9] Control-flow Enforcement: Indirect Branch Tracking, PTRACE Yu-cheng Yu
2020-08-25 0:26 ` [PATCH v11 1/9] x86/cet/ibt: Add Kconfig option for user-mode Indirect Branch Tracking Yu-cheng Yu
2020-08-25 0:26 ` [PATCH v11 2/9] x86/cet/ibt: User-mode Indirect Branch Tracking support Yu-cheng Yu
2020-08-25 0:26 ` [PATCH v11 3/9] x86/cet/ibt: Handle signals for Indirect Branch Tracking Yu-cheng Yu
2020-08-25 0:26 ` [PATCH v11 4/9] x86/cet/ibt: ELF header parsing " Yu-cheng Yu
2020-08-25 0:26 ` [PATCH v11 5/9] x86/cet/ibt: Update arch_prctl functions " Yu-cheng Yu
2020-08-25 0:26 ` [PATCH v11 6/9] x86/cet: Add PTRACE interface for CET Yu-cheng Yu
2020-09-02 20:03 ` Jann Horn
2020-09-02 22:13 ` Yu, Yu-cheng
2020-09-02 23:50 ` Andy Lutomirski
2020-09-03 2:53 ` Yu, Yu-cheng
2020-09-03 4:35 ` Andy Lutomirski
2020-09-03 14:26 ` Dave Hansen
2020-09-03 14:54 ` Andy Lutomirski
2020-09-03 16:09 ` Yu, Yu-cheng
2020-09-03 16:11 ` Dave Hansen
2020-09-03 16:15 ` Andy Lutomirski
2020-09-03 16:25 ` Dave Hansen
2020-09-03 16:32 ` Andy Lutomirski
2020-09-03 16:42 ` Dave Hansen
2020-09-03 17:59 ` Yu, Yu-cheng
2020-09-03 16:21 ` Yu, Yu-cheng
2020-09-03 16:25 ` Andy Lutomirski
2020-09-03 0:33 ` Jann Horn
2020-09-03 2:53 ` Yu, Yu-cheng
2020-08-25 0:26 ` [PATCH v11 7/9] x86/vdso/32: Add ENDBR32 to __kernel_vsyscall entry point Yu-cheng Yu
2020-08-25 0:26 ` [PATCH v11 8/9] x86/vdso: Insert endbr32/endbr64 to vDSO Yu-cheng Yu
2020-08-25 0:33 ` Andy Lutomirski
2020-08-25 16:13 ` Yu, Yu-cheng
2020-08-25 0:26 ` [PATCH v11 9/9] x86: Disallow vsyscall emulation when CET is enabled Yu-cheng Yu
2020-08-25 0:32 ` Andy Lutomirski
2020-08-25 9:14 ` Florian Weimer [this message]
2020-08-25 15:08 ` Yu, Yu-cheng
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