From: Sasha Levin <sashal@kernel.org>
To: hpa@zytor.com
Cc: Thomas Gleixner <tglx@linutronix.de>,
Don Porter <porter@cs.unc.edu>,
Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
Andi Kleen <ak@linux.intel.com>,
linux-kernel@vger.kernel.org, bp@alien8.de, luto@kernel.org,
dave.hansen@intel.com, tony.luck@intel.com,
ravi.v.shankar@intel.com, chang.seok.bae@intel.com
Subject: Re: Re: [PATCH v12 00/18] Enable FSGSBASE instructions
Date: Sun, 24 May 2020 17:19:45 -0400 [thread overview]
Message-ID: <20200524211945.GX33628@sasha-vm> (raw)
In-Reply-To: <A9483B8B-C0DD-46CB-AD5D-D12EC61BB331@zytor.com>
On Sun, May 24, 2020 at 12:45:18PM -0700, hpa@zytor.com wrote:
>There are legitimate reasons to write a root-hole module, the main one being able to test security features like SMAP. I have requested before a TAINT flag specifically for this purpose, because TAINT_CRAP is nowhere near explicit enough, and is also used for staging drivers. Call it TAINT_TOXIC or TAINT_ROOTHOLE; it should always be accompanied with a CRIT level alert.
What I don't like about our current system of TAINT_* flags is that
while we can improve it as much as we want, no one outside of the kernel
tree seems to be using it. While Thomas may have been commenting on
Graphene's behaviour, look at any other code that did the same thing:
- Graphene: https://github.com/oscarlab/graphene-sgx-driver/blob/master/gsgx.c
- Occlum: https://github.com/occlum/enable_rdfsbase/blob/master/enable_rdfsbase.c
- SGX-LKL: https://github.com/lsds/sgx-lkl/blob/master/tools/kmod-set-fsgsbase/mod_set_cr4_fsgsbase.c
None of which set even the CRAP flag.
--
Thanks,
Sasha
next prev parent reply other threads:[~2020-05-24 21:19 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-11 4:52 [PATCH v12 00/18] Enable FSGSBASE instructions Sasha Levin
2020-05-11 4:52 ` [PATCH v12 01/18] x86/ptrace: Prevent ptrace from clearing the FS/GS selector Sasha Levin
2020-05-11 4:52 ` [PATCH v12 02/18] selftests/x86/fsgsbase: Test GS selector on ptracer-induced GS base write Sasha Levin
2020-05-11 4:52 ` [PATCH v12 03/18] x86/cpu: Add 'unsafe_fsgsbase' to enable CR4.FSGSBASE Sasha Levin
2020-05-11 4:52 ` [PATCH v12 04/18] x86/entry/64: Clean up paranoid exit Sasha Levin
2020-05-11 4:52 ` [PATCH v12 05/18] x86/entry/64: Switch CR3 before SWAPGS in paranoid entry Sasha Levin
2020-05-11 4:52 ` [PATCH v12 06/18] x86/entry/64: Introduce the FIND_PERCPU_BASE macro Sasha Levin
2020-05-11 4:53 ` [PATCH v12 07/18] x86/entry/64: Handle FSGSBASE enabled paranoid entry/exit Sasha Levin
2020-05-11 4:53 ` [PATCH v12 08/18] x86/entry/64: Document GSBASE handling in the paranoid path Sasha Levin
2020-05-11 4:53 ` [PATCH v12 09/18] x86/fsgsbase/64: Add intrinsics for FSGSBASE instructions Sasha Levin
2020-05-11 4:53 ` [PATCH v12 10/18] x86/fsgsbase/64: Enable FSGSBASE instructions in helper functions Sasha Levin
2020-05-18 18:20 ` Thomas Gleixner
2020-05-18 20:24 ` Sasha Levin
2020-05-18 22:59 ` Thomas Gleixner
2020-05-19 12:20 ` David Laight
2020-05-19 14:48 ` Thomas Gleixner
2020-05-20 9:13 ` David Laight
2020-05-11 4:53 ` [PATCH v12 11/18] x86/fsgsbase/64: Use FSGSBASE in switch_to() if available Sasha Levin
2020-05-11 4:53 ` [PATCH v12 12/18] x86/fsgsbase/64: move save_fsgs to header file Sasha Levin
2020-05-11 4:53 ` [PATCH v12 13/18] x86/fsgsbase/64: Use FSGSBASE instructions on thread copy and ptrace Sasha Levin
2020-05-11 4:53 ` [PATCH v12 14/18] x86/speculation/swapgs: Check FSGSBASE in enabling SWAPGS mitigation Sasha Levin
2020-05-11 4:53 ` [PATCH v12 15/18] selftests/x86/fsgsbase: Test ptracer-induced GS base write with FSGSBASE Sasha Levin
2020-05-11 4:53 ` [PATCH v12 16/18] x86/fsgsbase/64: Enable FSGSBASE on 64bit by default and add a chicken bit Sasha Levin
2020-05-11 4:53 ` [PATCH v12 17/18] x86/elf: Enumerate kernel FSGSBASE capability in AT_HWCAP2 Sasha Levin
2020-05-11 4:53 ` [PATCH v12 18/18] Documentation/x86/64: Add documentation for GS/FS addressing mode Sasha Levin
2020-05-15 9:24 ` [PATCH v12 00/18] Enable FSGSBASE instructions Jarkko Sakkinen
2020-05-15 16:40 ` Sasha Levin
2020-05-15 17:55 ` Andi Kleen
2020-05-15 23:07 ` Sasha Levin
2020-05-16 12:21 ` Jarkko Sakkinen
2020-05-16 9:50 ` Jarkko Sakkinen
2020-05-18 15:34 ` Andi Kleen
2020-05-18 20:01 ` Jarkko Sakkinen
2020-05-18 23:03 ` Thomas Gleixner
2020-05-19 16:48 ` Jarkko Sakkinen
2020-05-22 20:14 ` Don Porter
2020-05-22 20:55 ` Dave Hansen
2020-05-23 0:45 ` Thomas Gleixner
2020-05-24 19:45 ` hpa
2020-05-24 21:19 ` Sasha Levin [this message]
2020-05-24 23:44 ` hpa
2020-05-25 7:54 ` Richard Weinberger
2020-05-25 21:56 ` Tony Luck
2020-05-26 8:12 ` David Laight
2020-05-26 8:23 ` Richard Weinberger
2020-05-27 8:31 ` Jarkko Sakkinen
2020-05-26 12:42 ` Don Porter
2020-05-26 20:27 ` Sasha Levin
2020-05-26 22:03 ` Don Porter
2020-05-26 22:51 ` Sasha Levin
2020-05-28 17:37 ` Don Porter
2020-05-28 10:29 ` Thomas Gleixner
2020-05-28 17:40 ` Don Porter
2020-05-28 18:38 ` Andy Lutomirski
2020-05-29 15:27 ` Wojtek Porczyk
2020-06-25 15:27 ` Don Porter
2020-06-25 21:37 ` Jarkko Sakkinen
2020-07-18 18:19 ` Don Porter
2020-07-23 3:23 ` Jarkko Sakkinen
2020-05-28 19:19 ` Jarkko Sakkinen
2020-05-28 19:41 ` Sasha Levin
2020-05-29 3:07 ` Jarkko Sakkinen
2020-05-29 3:10 ` Jarkko Sakkinen
2020-06-25 15:30 ` Don Porter
2020-06-25 21:40 ` Jarkko Sakkinen
2020-05-23 4:19 ` Andi Kleen
2020-05-28 10:36 ` Thomas Gleixner
2020-05-27 8:20 ` Jarkko Sakkinen
2020-05-27 12:42 ` Wojtek Porczyk
2020-05-18 9:51 ` Thomas Gleixner
2020-05-18 15:16 ` Sasha Levin
2020-05-18 18:28 ` Thomas Gleixner
2020-05-18 19:36 ` Jarkko Sakkinen
2020-05-18 6:18 ` Christoph Hellwig
2020-05-18 12:33 ` Sasha Levin
2020-05-18 14:53 ` Thomas Gleixner
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