From: Dave Hansen <dave.hansen@intel.com>
To: Andy Lutomirski <luto@kernel.org>
Cc: "Yu, Yu-cheng" <yu-cheng.yu@intel.com>,
Jann Horn <jannh@google.com>,
the arch/x86 maintainers <x86@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
kernel list <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>,
Florian Weimer <fweimer@redhat.com>,
"H.J. Lu" <hjl.tools@gmail.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 6/9] x86/cet: Add PTRACE interface for CET
Date: Thu, 3 Sep 2020 09:25:54 -0700 [thread overview]
Message-ID: <21491d05-6306-0a6f-58a7-8bf29feae8c7@intel.com> (raw)
In-Reply-To: <CALCETrUq3xiHV2xOZV-FD_de_P_TL-Bs91XT+F+79psBfigCSg@mail.gmail.com>
On 9/3/20 9:15 AM, Andy Lutomirski wrote:
> On Thu, Sep 3, 2020 at 9:12 AM Dave Hansen <dave.hansen@intel.com> wrote:
>>
>> On 9/3/20 9:09 AM, Yu, Yu-cheng wrote:
>>> If the debugger is going to write an MSR, only in the third case would
>>> this make a slight sense. For example, if the system has CET enabled,
>>> but the task does not have CET enabled, and GDB is writing to a CET MSR.
>>> But still, this is strange to me.
>>
>> If this is strange, then why do we even _implement_ writes?
>
> Well, if gdb wants to force a tracee to return early from a function,
> wouldn't it want the ability to modify SSP?
That's true.
Yu-cheng, can you take a look through and see for the other setregs
users what they do for logically crazy, strange things? Is there
precedent for refusing a write which is possible but illogical or
strange? If so, which error code do they use?
Taking the config register out of the init state is illogical, as is
writing to SSP while the config register is in its init state.
next prev parent reply other threads:[~2020-09-03 16:26 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 [this message]
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
2020-08-25 15:08 ` Yu, Yu-cheng
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