From: Dave Hansen <dave.hansen@intel.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
x86@kernel.org, linux-sgx@vger.kernel.org,
linux-kernel@vger.kernel.org,
Jethro Beekman <jethro@fortanix.com>,
Haitao Huang <haitao.huang@linux.intel.com>,
Chunyang Hui <sanqian.hcy@antfin.com>,
Jordan Hand <jorhand@linux.microsoft.com>,
Nathaniel McCallum <npmccallum@redhat.com>,
Seth Moore <sethmo@google.com>,
Darren Kenny <darren.kenny@oracle.com>,
Suresh Siddha <suresh.b.siddha@intel.com>,
akpm@linux-foundation.org, andriy.shevchenko@linux.intel.com,
asapek@google.com, bp@alien8.de, cedric.xing@intel.com,
chenalexchen@google.com, conradparker@google.com,
cyhanish@google.com, haitao.huang@intel.com, kai.huang@intel.com,
kai.svahn@intel.com, kmoy@google.com, ludloff@google.com,
luto@kernel.org, nhorman@redhat.com, puiterwijk@redhat.com,
rientjes@google.com, tglx@linutronix.de, yaozhangx@google.com,
mikko.ylinen@intel.com
Subject: Re: [PATCH v39 13/24] x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES
Date: Mon, 19 Oct 2020 14:44:19 -0700 [thread overview]
Message-ID: <564152e4-2334-2c82-1a12-4c980b08a944@intel.com> (raw)
In-Reply-To: <20201019211525.GC23072@linux.intel.com>
On 10/19/20 2:15 PM, Sean Christopherson wrote:
>>>> Yeah... Don't we need to do another access_ok() check here, if we
>>>> needed one above since we are moving away from addrp.src?
>>> I don't think so because the page is pinned with get_user_pages().
>> No, get_user_pages() is orthogonal.
>>
>> Looking at this again, you _might_ be OK since you validated addp.length
>> against encl->size. But, it's all very convoluted and doesn't look very
>> organized or obviously right.
> The easiest fix would be to have the existing access_ok() check the entire
> range, no? Or am I missing something obvious?
In general, I want the actual userspace access to be as close as
possible and 1:1 with the access_ok() checks. That way, it's blatantly
obvious that the pointers have been checked.
*But* get_user_pages() has access_ok() checks inside of its
implementation, which makes sense. *But*, that begs the question of
what the top-level one was doing in the first place. Maybe it was just
superfluous.
Either way, it still doesn't explain what this is doing:
> + ret = get_user_pages(src, 1, 0, &src_page, NULL);
> + if (ret < 1)
> + return -EFAULT;
> +
> + pginfo.secs = (unsigned long)sgx_get_epc_addr(encl->secs.epc_page);
> + pginfo.addr = SGX_ENCL_PAGE_ADDR(encl_page);
> + pginfo.metadata = (unsigned long)secinfo;
> + pginfo.contents = (unsigned long)kmap_atomic(src_page);
> +
> + ret = __eadd(&pginfo, sgx_get_epc_addr(epc_page));
> +
> + kunmap_atomic((void *)pginfo.contents);
I think the point is to create a stable kernel alias address for
'src_page' so that any mucking with the userspace mapping doesn't screw
up the __eadd() and any failures aren't due to reclaim or MADV_DONTNEED.
If this isn't even touching the userspace mapping, it didn't need
access_ok() in the first place.
next prev parent reply other threads:[~2020-10-19 21:44 UTC|newest]
Thread overview: 117+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-03 4:50 [PATCH v39 00/24] Intel SGX foundations Jarkko Sakkinen
2020-10-03 4:50 ` [PATCH v39 01/24] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
2020-10-19 14:10 ` Dave Hansen
2020-10-19 17:49 ` Sean Christopherson
2020-10-03 4:50 ` [PATCH v39 02/24] x86/cpufeatures: x86/msr: Add Intel SGX Launch Control " Jarkko Sakkinen
2020-10-03 4:50 ` [PATCH v39 03/24] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
2020-10-03 4:50 ` [PATCH v39 04/24] x86/sgx: Add SGX microarchitectural data structures Jarkko Sakkinen
2020-10-03 4:50 ` [PATCH v39 05/24] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2020-10-19 14:30 ` Dave Hansen
2020-10-19 17:38 ` Sean Christopherson
2020-10-19 17:48 ` Dave Hansen
2020-10-19 17:53 ` Sean Christopherson
2020-10-19 17:58 ` Dave Hansen
2020-10-03 4:50 ` [PATCH v39 06/24] x86/cpu/intel: Detect SGX support Jarkko Sakkinen
2020-10-03 4:50 ` [PATCH v39 07/24] x86/cpu/intel: Add nosgx kernel parameter Jarkko Sakkinen
2020-10-03 4:50 ` [PATCH v39 08/24] x86/sgx: Initialize metadata for Enclave Page Cache (EPC) sections Jarkko Sakkinen
2020-10-19 8:45 ` Jarkko Sakkinen
2020-10-19 12:39 ` Borislav Petkov
2020-10-23 9:01 ` Jarkko Sakkinen
2020-10-19 13:40 ` Dave Hansen
2020-10-23 9:03 ` Jarkko Sakkinen
2020-10-03 4:50 ` [PATCH v39 09/24] x86/sgx: Add __sgx_alloc_epc_page() and sgx_free_epc_page() Jarkko Sakkinen
2020-10-03 4:50 ` [PATCH v39 10/24] mm: Add 'mprotect' hook to struct vm_operations_struct Jarkko Sakkinen
2020-10-03 4:50 ` [PATCH v39 11/24] x86/sgx: Add SGX enclave driver Jarkko Sakkinen
2020-10-03 14:39 ` Greg KH
2020-10-04 14:32 ` Jarkko Sakkinen
2020-10-04 15:01 ` Jarkko Sakkinen
2020-10-05 9:42 ` Greg KH
2020-10-05 12:42 ` Jarkko Sakkinen
2020-10-07 18:09 ` Haitao Huang
2020-10-07 19:26 ` Greg KH
2020-10-09 6:44 ` Jarkko Sakkinen
2020-10-14 20:16 ` Dave Hansen
2020-10-05 8:45 ` Christoph Hellwig
2020-10-05 11:42 ` Jarkko Sakkinen
2020-10-05 11:50 ` Greg KH
2020-10-05 14:23 ` Jarkko Sakkinen
2020-10-05 15:02 ` Greg KH
2020-10-05 16:40 ` Dave Hansen
2020-10-05 20:02 ` Jarkko Sakkinen
2020-10-09 7:10 ` Pavel Machek
2020-10-09 7:21 ` Greg KH
2020-10-09 8:21 ` Pavel Machek
2020-10-03 19:54 ` Matthew Wilcox
2020-10-04 21:50 ` Jarkko Sakkinen
2020-10-04 22:02 ` Jarkko Sakkinen
2020-10-04 22:27 ` Matthew Wilcox
2020-10-04 23:41 ` Jarkko Sakkinen
2020-10-05 1:30 ` Matthew Wilcox
2020-10-05 3:06 ` Jarkko Sakkinen
2020-10-03 4:50 ` [PATCH v39 12/24] x86/sgx: Add SGX_IOC_ENCLAVE_CREATE Jarkko Sakkinen
2020-10-16 17:07 ` Dave Hansen
2020-10-18 4:26 ` Jarkko Sakkinen
2020-10-19 20:21 ` Dave Hansen
2020-10-19 20:48 ` Sean Christopherson
2020-10-03 4:50 ` [PATCH v39 13/24] x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES Jarkko Sakkinen
2020-10-16 21:25 ` Dave Hansen
2020-10-18 5:03 ` Jarkko Sakkinen
2020-10-19 7:03 ` Jarkko Sakkinen
2020-10-19 20:48 ` Dave Hansen
2020-10-19 21:15 ` Sean Christopherson
2020-10-19 21:44 ` Dave Hansen [this message]
2020-10-23 10:11 ` Jarkko Sakkinen
2020-10-03 4:50 ` [PATCH v39 14/24] x86/sgx: Add SGX_IOC_ENCLAVE_INIT Jarkko Sakkinen
2020-10-03 4:50 ` [PATCH v39 15/24] x86/sgx: Add SGX_IOC_ENCLAVE_PROVISION Jarkko Sakkinen
2020-10-20 15:48 ` Dave Hansen
2020-10-23 10:14 ` Jarkko Sakkinen
2020-10-20 21:19 ` Dave Hansen
2020-10-23 10:17 ` Jarkko Sakkinen
2020-10-23 14:19 ` Dave Hansen
2020-10-24 11:34 ` Jarkko Sakkinen
2020-10-24 15:47 ` Andy Lutomirski
2020-10-24 20:23 ` Jarkko Sakkinen
2020-10-27 10:38 ` Dr. Greg
2020-10-23 14:23 ` Jethro Beekman
2020-10-24 11:40 ` Jarkko Sakkinen
2020-10-03 4:50 ` [PATCH v39 16/24] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2020-10-03 5:22 ` Haitao Huang
2020-10-03 13:32 ` Jarkko Sakkinen
2020-10-03 18:23 ` Haitao Huang
2020-10-04 22:39 ` Jarkko Sakkinen
2020-10-07 17:25 ` Jarkko Sakkinen
2020-10-03 4:50 ` [PATCH v39 17/24] x86/sgx: Add ptrace() support for the SGX driver Jarkko Sakkinen
2020-10-03 4:50 ` [PATCH v39 18/24] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2020-10-03 4:50 ` [PATCH v39 19/24] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2020-10-03 4:50 ` [PATCH v39 20/24] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2020-10-03 4:50 ` [PATCH v39 21/24] x86/vdso: Implement a vDSO for Intel SGX enclave call Jarkko Sakkinen
2020-10-06 2:57 ` Sean Christopherson
2020-10-06 8:30 ` Jethro Beekman
2020-10-06 15:15 ` Sean Christopherson
2020-10-06 17:28 ` Jarkko Sakkinen
2020-10-06 23:21 ` Sean Christopherson
2020-10-07 0:22 ` Jarkko Sakkinen
2020-10-07 1:17 ` Sean Christopherson
2020-10-07 3:14 ` Jarkko Sakkinen
2020-10-07 4:34 ` Sean Christopherson
2020-10-07 7:39 ` Jarkko Sakkinen
2020-10-07 8:04 ` Jarkko Sakkinen
2020-10-07 15:25 ` Sean Christopherson
2020-10-07 17:08 ` Jarkko Sakkinen
2020-10-07 17:13 ` Jarkko Sakkinen
2020-10-06 15:49 ` Jarkko Sakkinen
2020-10-06 15:36 ` Jarkko Sakkinen
2020-10-06 21:39 ` Jarkko Sakkinen
2020-10-07 0:23 ` Jarkko Sakkinen
2020-10-17 1:48 ` Andy Lutomirski
2020-10-17 21:02 ` Jarkko Sakkinen
2020-10-03 4:50 ` [PATCH v39 22/24] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2020-10-12 16:50 ` Jarkko Sakkinen
2020-10-03 4:50 ` [PATCH v39 23/24] docs: x86/sgx: Document SGX micro architecture and kernel internals Jarkko Sakkinen
2020-10-03 4:50 ` [PATCH v39 24/24] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2020-10-16 21:04 ` Dave Hansen
2020-10-18 4:27 ` Jarkko Sakkinen
2020-10-03 14:32 ` [PATCH v39 00/24] Intel SGX foundations Greg KH
2020-10-03 14:53 ` Jarkko Sakkinen
2020-10-15 19:06 ` Dave Hansen
2020-10-17 20:43 ` Jarkko Sakkinen
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