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From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Cedric Xing <cedric.xing@intel.com>
Cc: linux-security-module@vger.kernel.org, selinux@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-sgx@vger.kernel.org,
	luto@kernel.org, sds@tycho.nsa.gov, jmorris@namei.org,
	serge@hallyn.com, paul@paul-moore.com, eparis@parisplace.org,
	jethro@fortanix.com, dave.hansen@intel.com, tglx@linutronix.de,
	torvalds@linux-foundation.org, akpm@linux-foundation.org,
	nhorman@redhat.com, pmccallum@redhat.com, serge.ayoun@intel.com,
	shay.katz-zamir@intel.com, haitao.huang@intel.com,
	andriy.shevchenko@linux.intel.com, kai.svahn@intel.com,
	bp@alien8.de, josh@joshtriplett.org, kai.huang@intel.com,
	rientjes@google.com, william.c.roberts@intel.com,
	philip.b.tricca@intel.com
Subject: Re: [RFC PATCH v1 0/3] security/x86/sgx: SGX specific LSM hooks
Date: Mon, 10 Jun 2019 20:36:45 +0300
Message-ID: <20190610173645.GA13732@linux.intel.com> (raw)
In-Reply-To: <cover.1560131039.git.cedric.xing@intel.com>

On Mon, Jun 10, 2019 at 12:03:03AM -0700, Cedric Xing wrote:
> This series intends to make the new SGX subsystem and the existing LSM
> architecture work together smoothly so that, say, SGX cannot be abused to work
> around restrictions set forth by LSM. This series applies on top of Jarkko
> Sakkinen's SGX series v20 (https://lkml.org/lkml/2019/4/17/344), where abundant
> details of this SGX/LSM problem could be found.
> 
> This series is an alternative to Sean Christopherson's recent RFC series
> (https://lkml.org/lkml/2019/6/5/1070) that was trying to solve the same
> problem. The key problem is for LSM to determine the "maximal (most permissive)
> protection" allowed for individual enclave pages. Sean's approach is to take
> that from user mode code as a parameter of the EADD ioctl, validate it with LSM
> ahead of time, and then enforce it inside the SGX subsystem. The major
> disadvantage IMHO is that a priori knowledge of "maximal protection" is needed,
> but it isn't always available in certain use cases. In fact, it is an unusual
> approach to take "maximal protection" from user code, as what SELinux is doing
> today is to determine "maximal protection" of a vma using attributes associated
> with vma->vm_file instead. When it comes to enclaves, vma->vm_file always
> points /dev/sgx/enclave, so what's missing is a new way for LSM modules to
> remember origins of enclave pages so that they don't solely depend on
> vma->vm_file to determine "maximal protection".
> 
> This series takes advantage of the fact that enclave pages cannot be remapped
> (to different linear address), therefore the pair of { vma->vm_file,
> linear_address } can be used to uniquely identify an enclave page. Then by
> notifying LSM on creation of every enclave page (via a new LSM hook -
> security_enclave_load), LSM modules would be able to track origin and
> protection changes of every page, hence be able to judge correctly upon
> mmap/mprotect requests.
> 
> Cedric Xing (3):
>   LSM/x86/sgx: Add SGX specific LSM hooks
>   LSM/x86/sgx: Implement SGX specific hooks in SELinux
>   LSM/x86/sgx: Call new LSM hooks from SGX subsystem

A patch set containing direct LSM changes should consider all LSMs.
This will allow all the LSM maintainers to consider the changes. Now we
have a limited audience and we are favoring one LSM.

There is no good reason why direct LSM changes cannot be done
post-upstreaming like we do for virtualization.

Looking at Sean's patches, overally 1/5-3/5 make perfect sense.

/Jarkko

      parent reply index

Thread overview: 67+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-06  2:11 [RFC PATCH v2 0/5] security: x86/sgx: SGX vs. LSM Sean Christopherson
2019-06-06  2:11 ` [RFC PATCH v2 1/5] mm: Introduce vm_ops->may_mprotect() Sean Christopherson
2019-06-10 15:06   ` Jarkko Sakkinen
2019-06-10 15:55     ` Sean Christopherson
2019-06-10 17:47       ` Xing, Cedric
2019-06-10 19:49         ` Sean Christopherson
2019-06-10 22:06           ` Xing, Cedric
2019-06-06  2:11 ` [RFC PATCH v2 2/5] x86/sgx: Require userspace to define enclave pages' protection bits Sean Christopherson
2019-06-10 15:27   ` Jarkko Sakkinen
2019-06-10 16:15     ` Sean Christopherson
2019-06-10 17:45       ` Jarkko Sakkinen
2019-06-10 18:17         ` Sean Christopherson
2019-06-12 19:26           ` Jarkko Sakkinen
2019-06-10 18:29   ` Xing, Cedric
2019-06-10 19:15     ` Andy Lutomirski
2019-06-10 22:28       ` Xing, Cedric
2019-06-12  0:09         ` Andy Lutomirski
2019-06-12 14:34           ` Sean Christopherson
2019-06-12 18:20             ` Xing, Cedric
2019-06-06  2:11 ` [RFC PATCH v2 3/5] x86/sgx: Enforce noexec filesystem restriction for enclaves Sean Christopherson
2019-06-10 16:00   ` Jarkko Sakkinen
2019-06-10 16:44     ` Andy Lutomirski
2019-06-11 17:21       ` Stephen Smalley
2019-06-06  2:11 ` [RFC PATCH v2 4/5] LSM: x86/sgx: Introduce ->enclave_load() hook for Intel SGX Sean Christopherson
2019-06-07 19:58   ` Stephen Smalley
2019-06-10 16:21     ` Sean Christopherson
2019-06-10 16:05   ` Jarkko Sakkinen
2019-06-06  2:11 ` [RFC PATCH v2 5/5] security/selinux: Add enclave_load() implementation Sean Christopherson
2019-06-07 21:16   ` Stephen Smalley
2019-06-10 16:46     ` Sean Christopherson
2019-06-17 16:38   ` Jarkko Sakkinen
2019-06-10  7:03 ` [RFC PATCH v1 0/3] security/x86/sgx: SGX specific LSM hooks Cedric Xing
2019-06-10  7:03   ` [RFC PATCH v1 1/3] LSM/x86/sgx: Add " Cedric Xing
2019-06-10  7:03   ` [RFC PATCH v1 2/3] LSM/x86/sgx: Implement SGX specific hooks in SELinux Cedric Xing
2019-06-11 13:40     ` Stephen Smalley
2019-06-11 22:02       ` Sean Christopherson
2019-06-12  9:32         ` Dr. Greg
2019-06-12 14:25           ` Sean Christopherson
2019-06-13  7:25             ` Dr. Greg
2019-06-12 19:30         ` Andy Lutomirski
2019-06-12 22:02           ` Sean Christopherson
2019-06-13  0:10             ` Xing, Cedric
2019-06-13  1:02             ` Xing, Cedric
2019-06-13 17:02         ` Stephen Smalley
2019-06-13 23:03           ` Xing, Cedric
2019-06-13 23:17             ` Sean Christopherson
2019-06-14  0:31               ` Xing, Cedric
2019-06-14  0:46           ` Sean Christopherson
2019-06-14 15:38             ` Sean Christopherson
2019-06-16 22:14               ` Andy Lutomirski
2019-06-17 16:49                 ` Sean Christopherson
2019-06-17 17:08                   ` Andy Lutomirski
2019-06-18 15:40                   ` Dr. Greg
2019-06-14 17:16             ` Xing, Cedric
2019-06-14 17:45               ` Sean Christopherson
2019-06-14 17:53                 ` Sean Christopherson
2019-06-14 20:01                   ` Sean Christopherson
2019-06-16 22:16               ` Andy Lutomirski
2019-06-14 23:19             ` Dr. Greg
2019-06-11 22:55       ` Xing, Cedric
2019-06-13 18:00         ` Stephen Smalley
2019-06-13 19:48           ` Sean Christopherson
2019-06-13 21:09             ` Xing, Cedric
2019-06-13 21:02           ` Xing, Cedric
2019-06-14  0:37           ` Sean Christopherson
2019-06-10  7:03   ` [RFC PATCH v1 3/3] LSM/x86/sgx: Call new LSM hooks from SGX subsystem Cedric Xing
2019-06-10 17:36   ` Jarkko Sakkinen [this message]

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