From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>, haitao.huang@intel.com
Cc: x86@kernel.org, linux-sgx@vger.kernel.org,
linux-kernel@vger.kernel.org,
Sean Christopherson <sean.j.christopherson@intel.com>,
Andy Lutomirski <luto@amacapital.net>,
Jethro Beekman <jethro@fortanix.com>,
Cedric Xing <cedric.xing@intel.com>,
akpm@linux-foundation.org, andriy.shevchenko@linux.intel.com,
asapek@google.com, bp@alien8.de, chenalexchen@google.com,
conradparker@google.com, cyhanish@google.com,
dave.hansen@intel.com, haitao.huang@intel.com,
josh@joshtriplett.org, kai.huang@intel.com, kai.svahn@intel.com,
kmoy@google.com, ludloff@google.com, luto@kernel.org,
nhorman@redhat.com, npmccallum@redhat.com, puiterwijk@redhat.com,
rientjes@google.com, tglx@linutronix.de, yaozhangx@google.com,
"H.J. Lu" <hjl.tools@gmail.com>,
Yu-cheng Yu <yu-cheng.yu@intel.com>
Subject: Re: [PATCH v38 21/24] x86/vdso: Implement a vDSO for Intel SGX enclave call
Date: Wed, 30 Sep 2020 03:52:28 +0300 [thread overview]
Message-ID: <20200930005228.GC805586@linux.intel.com> (raw)
In-Reply-To: <7a3e45a5-513a-1d77-fa64-8f4a9f67e3ab@citrix.com>
On Tue, Sep 29, 2020 at 12:52:35AM +0100, Andrew Cooper wrote:
> On 28/09/2020 21:42, Jarkko Sakkinen wrote:
> > On Mon, Sep 28, 2020 at 05:44:35PM +0100, Andrew Cooper wrote:
> >> On 28/09/2020 01:58, Jarkko Sakkinen wrote:
> >>> On Fri, Sep 25, 2020 at 07:23:59PM +0100, Andrew Cooper wrote:
> >>>> On 15/09/2020 12:28, Jarkko Sakkinen wrote:
> >>>>> diff --git a/arch/x86/entry/vdso/vsgx_enter_enclave.S b/arch/x86/entry/vdso/vsgx_enter_enclave.S
> >>>>> new file mode 100644
> >>>>> index 000000000000..adbd59d41517
> >>>>> --- /dev/null
> >>>>> +++ b/arch/x86/entry/vdso/vsgx_enter_enclave.S
> >>>>> @@ -0,0 +1,157 @@
> >>>>> +SYM_FUNC_START(__vdso_sgx_enter_enclave)
> >>>>> <snip>
> >>>>> +.Lretpoline:
> >>>>> + call 2f
> >>>>> +1: pause
> >>>>> + lfence
> >>>>> + jmp 1b
> >>>>> +2: mov %rax, (%rsp)
> >>>>> + ret
> >>>> I hate to throw further spanners in the work, but this is not compatible
> >>>> with CET, and the user shadow stack work in progress.
> >>> CET goes beyond my expertise. Can you describe, at least rudimentary,
> >>> how this code is not compatible?
> >> CET Shadow Stacks detect attacks which modify the return address on the
> >> stack.
> >>
> >> Retpoline *is* a ROP gadget. It really does modify the return address
> >> on the stack, even if its purpose is defensive (vs Spectre v2) rather
> >> than malicious.
> > Aah. I get that, yes.
> >
> > Kernel is full of retpoline but I presume that ring-0 does not use CET.
>
> No-one has implemented support CET-SS support for Linux itself yet, but
> other kernels do have it working.
>
> ~Andrew
Haitao, can you point out the user handler callback in the Intel
SGX runtime?
There is only one single global callback in a practical deployment
provided by the runtime. AFAIK, it just copies values, does not do any
rountrips and is generally very trivial peace of code but it is better
to check it before final say.
I've now experimented with ALTERNATIVE() and it can be definitely made
work. I'm just thinking that would it be best not use retpoline at all?
My guess is that the callback would not have much applicability in
Spectre'ish attacks but do not have enough expertise on that to even
semiformally conclude it.
My intention is to find reasonable conclusions to drop it instead of
adding more complexity to the vDSO.
/Jarkko
next prev parent reply other threads:[~2020-09-30 0:52 UTC|newest]
Thread overview: 183+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-15 11:28 [PATCH v38 00/24] Intel SGX foundations Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 01/24] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 02/24] x86/cpufeatures: x86/msr: Add Intel SGX Launch Control " Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 03/24] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
2020-09-16 11:44 ` Borislav Petkov
2020-09-16 20:30 ` Jarkko Sakkinen
2020-09-16 20:32 ` Borislav Petkov
2020-09-15 11:28 ` [PATCH v38 04/24] x86/sgx: Add SGX microarchitectural data structures Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 05/24] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 06/24] x86/cpu/intel: Detect SGX support Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 07/24] x86/cpu/intel: Add nosgx kernel parameter Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 08/24] x86/sgx: Initialize metadata for Enclave Page Cache (EPC) sections Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 09/24] x86/sgx: Add __sgx_alloc_epc_page() and sgx_free_epc_page() Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 10/24] mm: Add vm_ops->mprotect() Jarkko Sakkinen
2020-09-18 12:44 ` Borislav Petkov
2020-09-18 15:09 ` Andy Lutomirski
2020-09-18 23:24 ` [PATCH v38 10/24] mm: Add vm_ops->mprotect()' Jarkko Sakkinen
2020-09-18 23:53 ` [PATCH v38 10/24] mm: Add vm_ops->mprotect() Sean Christopherson
2020-09-19 0:15 ` Andy Lutomirski
[not found] ` <20200922125801.GA133710@linux.intel.com>
2020-09-22 15:11 ` Dave Hansen
2020-09-23 13:30 ` Jarkko Sakkinen
2020-09-23 13:43 ` Jarkko Sakkinen
2020-09-23 14:33 ` Jarkko Sakkinen
2020-09-24 14:50 ` Dave Hansen
2020-09-24 16:27 ` Sean Christopherson
[not found] ` <20200921124946.GF6038@linux.intel.com>
2020-09-21 12:51 ` Jarkko Sakkinen
2020-09-21 13:14 ` Jarkko Sakkinen
[not found] ` <20200921165758.GA24156@linux.intel.com>
2020-09-21 21:07 ` Jarkko Sakkinen
2020-09-21 21:18 ` Sean Christopherson
2020-09-22 5:29 ` Jarkko Sakkinen
2020-09-22 5:35 ` Jarkko Sakkinen
2020-09-22 16:43 ` Sean Christopherson
2020-09-23 13:50 ` Jarkko Sakkinen
2020-09-24 19:11 ` Haitao Huang
2020-09-24 19:28 ` Sean Christopherson
2020-09-24 19:39 ` Dave Hansen
2020-09-24 20:01 ` Sean Christopherson
2020-09-24 20:10 ` Dave Hansen
2020-09-24 20:25 ` Sean Christopherson
2020-09-24 20:54 ` Dave Hansen
2020-09-24 23:05 ` Sean Christopherson
2020-09-24 23:09 ` Dave Hansen
2020-09-25 0:00 ` Sean Christopherson
2020-09-25 17:18 ` Dave Hansen
2020-09-25 19:43 ` Sean Christopherson
2020-09-25 19:53 ` Dave Hansen
2020-09-26 4:15 ` Andy Lutomirski
2020-09-28 0:53 ` Jarkko Sakkinen
2020-09-28 14:04 ` Dave Hansen
2020-09-28 16:19 ` Jarkko Sakkinen
2020-09-28 16:48 ` Dave Hansen
2020-09-28 19:32 ` Jarkko Sakkinen
2020-09-28 19:45 ` Dave Hansen
2020-09-28 20:19 ` Jarkko Sakkinen
2020-09-29 1:37 ` Andy Lutomirski
2020-09-29 4:05 ` Jarkko Sakkinen
2020-09-29 14:24 ` Dave Hansen
2020-09-30 0:20 ` Jarkko Sakkinen
2020-09-30 14:35 ` Dave Hansen
2020-09-28 20:18 ` Jarkko Sakkinen
2020-10-18 8:49 ` Dr. Greg
2020-10-19 21:31 ` Sean Christopherson
2020-10-20 10:01 ` Dr. Greg
2020-10-20 16:40 ` Sean Christopherson
2020-10-24 14:37 ` Dr. Greg
2020-10-24 15:33 ` Andy Lutomirski
2020-10-26 10:51 ` Dr. Greg
2020-10-26 22:59 ` Andy Lutomirski
2020-10-27 0:40 ` Sean Christopherson
2020-09-24 22:07 ` Jarkko Sakkinen
2020-09-24 21:58 ` Jarkko Sakkinen
2020-09-24 21:55 ` Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 11/24] x86/sgx: Add SGX enclave driver Jarkko Sakkinen
2020-09-21 9:30 ` Borislav Petkov
2020-09-21 12:09 ` Jarkko Sakkinen
2020-10-01 17:36 ` Sean Christopherson
2020-10-01 18:49 ` Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 12/24] x86/sgx: Add SGX_IOC_ENCLAVE_CREATE Jarkko Sakkinen
2020-09-21 10:03 ` Borislav Petkov
2020-09-21 12:28 ` Jarkko Sakkinen
2020-09-21 13:51 ` Borislav Petkov
2020-09-21 19:29 ` Jarkko Sakkinen
2020-10-03 0:23 ` Haitao Huang
2020-10-03 3:24 ` Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 13/24] x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 14/24] x86/sgx: Add SGX_IOC_ENCLAVE_INIT Jarkko Sakkinen
2020-09-21 17:35 ` Borislav Petkov
2020-09-21 18:10 ` Sean Christopherson
2020-09-21 18:27 ` Borislav Petkov
[not found] ` <20200921191658.GA24823@linux.intel.com>
2020-09-22 8:29 ` Borislav Petkov
2020-09-22 11:50 ` Jarkko Sakkinen
2020-09-22 12:56 ` Jethro Beekman
2020-09-22 14:29 ` Borislav Petkov
2020-09-23 14:47 ` Jarkko Sakkinen
2020-09-23 15:55 ` Borislav Petkov
2020-09-24 12:23 ` Jarkko Sakkinen
2020-09-22 16:29 ` Sean Christopherson
2020-09-21 19:22 ` Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 15/24] x86/sgx: Enable provisioning for remote attestation Jarkko Sakkinen
2020-09-21 18:07 ` Borislav Petkov
2020-09-21 19:27 ` Jarkko Sakkinen
2020-09-21 19:41 ` Borislav Petkov
2020-09-21 21:26 ` Jarkko Sakkinen
2020-09-22 8:30 ` Borislav Petkov
2020-09-15 11:28 ` [PATCH v38 16/24] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2020-09-22 10:45 ` Borislav Petkov
2020-09-22 14:03 ` Jarkko Sakkinen
2020-09-22 14:24 ` Borislav Petkov
2020-09-23 14:52 ` Jarkko Sakkinen
2020-09-29 1:14 ` Sean Christopherson
2020-09-29 3:50 ` Jarkko Sakkinen
2020-09-29 8:35 ` Sean Christopherson
2020-09-22 16:24 ` Sean Christopherson
2020-09-22 18:02 ` Borislav Petkov
2020-09-23 15:25 ` Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 17/24] x86/sgx: ptrace() support for the SGX driver Jarkko Sakkinen
2020-09-22 15:44 ` Borislav Petkov
2020-09-23 13:20 ` Jarkko Sakkinen
2020-09-23 16:17 ` Borislav Petkov
2020-09-24 11:51 ` Jarkko Sakkinen
2020-09-24 15:57 ` Borislav Petkov
2020-09-24 20:38 ` [PATCH v38 17/24] x86/sgx: ptrace() support for the SGX driver' Jarkko Sakkinen
2020-09-24 20:40 ` Jarkko Sakkinen
2020-09-25 7:53 ` Borislav Petkov
2020-09-25 11:00 ` Jarkko Sakkinen
2020-09-25 7:51 ` Borislav Petkov
2020-09-25 11:21 ` Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 18/24] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2020-09-23 22:07 ` Borislav Petkov
2020-09-24 12:09 ` Jarkko Sakkinen
2020-09-24 16:00 ` Borislav Petkov
2020-09-24 21:07 ` Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 19/24] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 20/24] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2020-09-24 16:31 ` Borislav Petkov
2020-09-24 23:11 ` Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 21/24] x86/vdso: Implement a vDSO for Intel SGX enclave call Jarkko Sakkinen
2020-09-24 18:04 ` Borislav Petkov
2020-09-25 1:00 ` Jarkko Sakkinen
2020-09-25 8:28 ` Borislav Petkov
2020-09-27 23:37 ` Jarkko Sakkinen
2020-09-28 8:30 ` Borislav Petkov
2020-09-28 15:02 ` Jarkko Sakkinen
2020-09-25 8:39 ` Jethro Beekman
2020-09-25 11:17 ` Jarkko Sakkinen
2020-09-25 11:43 ` Jethro Beekman
[not found] ` <20200925003808.GB20333@linux.intel.com>
2020-09-25 1:04 ` Jarkko Sakkinen
2020-09-25 8:14 ` Borislav Petkov
2020-09-25 10:59 ` Jarkko Sakkinen
2020-09-28 14:36 ` Jarkko Sakkinen
2020-09-25 18:23 ` Andrew Cooper
2020-09-28 0:58 ` Jarkko Sakkinen
2020-09-28 16:44 ` Andrew Cooper
2020-09-28 18:07 ` H.J. Lu
2020-09-28 18:12 ` Andy Lutomirski
2020-09-28 18:17 ` Dave Hansen
2020-09-28 22:07 ` Jarkko Sakkinen
2020-09-28 21:56 ` Jarkko Sakkinen
2020-09-28 22:06 ` H.J. Lu
2020-09-28 22:18 ` Dave Hansen
2020-09-28 22:41 ` Andy Lutomirski
2020-09-28 23:38 ` Andrew Cooper
2020-09-29 14:10 ` Dave Hansen
2020-09-29 15:01 ` Andrew Cooper
2020-09-28 21:41 ` Jarkko Sakkinen
2020-09-28 20:42 ` Jarkko Sakkinen
2020-09-28 23:52 ` Andrew Cooper
2020-09-30 0:52 ` Jarkko Sakkinen [this message]
2020-09-28 15:43 ` Yu, Yu-cheng
2020-09-28 15:54 ` H.J. Lu
2020-09-28 16:40 ` Yu, Yu-cheng
2020-09-28 21:36 ` Jarkko Sakkinen
2020-09-28 20:56 ` Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 22/24] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2020-09-15 11:28 ` [PATCH v38 23/24] docs: x86/sgx: Document SGX micro architecture and kernel internals Jarkko Sakkinen
2020-09-23 13:50 ` Borislav Petkov
2020-09-24 11:28 ` Jarkko Sakkinen
2020-09-24 15:54 ` Borislav Petkov
2020-09-15 11:28 ` [PATCH v38 24/24] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2020-09-25 22:37 ` Sean Christopherson
2020-09-28 0:44 ` Jarkko Sakkinen
-- strict thread matches above, loose matches on Subject: below --
2020-09-15 11:04 [PATCH v38 00/24] Intel SGX foundations Jarkko Sakkinen
2020-09-15 11:05 ` [PATCH v38 21/24] x86/vdso: Implement a vDSO for Intel SGX enclave call Jarkko Sakkinen
2020-09-28 1:32 ` Jarkko Sakkinen
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