From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Stephen Smalley <sds@tycho.nsa.gov>
Cc: "Xing, Cedric" <cedric.xing@intel.com>,
Andy Lutomirski <luto@kernel.org>,
Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
James Morris <jmorris@namei.org>,
"Serge E. Hallyn" <serge@hallyn.com>,
LSM List <linux-security-module@vger.kernel.org>,
Paul Moore <paul@paul-moore.com>,
Eric Paris <eparis@parisplace.org>,
"selinux@vger.kernel.org" <selinux@vger.kernel.org>,
Jethro Beekman <jethro@fortanix.com>,
"Hansen, Dave" <dave.hansen@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
"Dr. Greg" <greg@enjellic.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
"linux-sgx@vger.kernel.org" <linux-sgx@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
"nhorman@redhat.com" <nhorman@redhat.com>,
"npmccallum@redhat.com" <npmccallum@redhat.com>,
"Ayoun, Serge" <serge.ayoun@intel.com>,
"Katz-zamir, Shay" <shay.katz-zamir@intel.com>,
"Huang, Haitao" <haitao.huang@intel.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
"Svahn, Kai" <kai.svahn@intel.com>,
Borislav Petkov <bp@alien8.de>,
Josh Triplett <josh@joshtriplett.org>,
"Huang, Kai" <kai.huang@intel.com>,
David Rientjes <rientjes@google.com>
Subject: Re: SGX vs LSM (Re: [PATCH v20 00/28] Intel SGX1 support)
Date: Fri, 24 May 2019 10:54:58 -0700 [thread overview]
Message-ID: <20190524175458.GB365@linux.intel.com> (raw)
In-Reply-To: <20190524174243.GA365@linux.intel.com>
On Fri, May 24, 2019 at 10:42:43AM -0700, Sean Christopherson wrote:
> Hmm, I've been thinking more about pulling permissions from the source
> page. Conceptually I'm not sure we need to meet the same requirements as
> non-enclave DSOs while the enclave is being built, i.e. do we really need
> to force userspace to fully map the enclave in normal memory?
>
> Consider the Graphene scenario where it's building an enclave on the fly.
> Pulling permissions from the source VMAs means Graphene has to map the
> code pages of the enclave with X. This means Graphene will need EXEDMOD
> (or EXECMEM if Graphene isn't careful). In a non-SGX scenario this makes
> perfect sense since there is no way to verify the end result of RW->RX.
>
> But for SGX, assuming enclaves are whitelisted by their sigstruct (checked
> at EINIT) and because page permissions affect sigstruct.MRENCLAVE, it *is*
> possible to verify the resulting RX contents. E.g. for the purposes of
> LSMs, can't we use the .sigstruct file as a proxy for the enclave and
> require FILE__EXECUTE on the .sigstruct inode to map/run the enclave?
>
> Stephen, is my logic sound?
>
>
> If so...
>
> - Require FILE__READ+FILE__EXECUTE on .sigstruct to mmap() the enclave.
>
> - Prevent userspace from mapping the enclave with permissions beyond the
> original permissions of the enclave. This can be done by populating
> VM_MAY{READ,WRITE,EXEC} from the SECINFO (same basic concept as Andy's
> proposals). E.g. pre-EINIT, mmap() and mprotect() can only succeed
> with PROT_NONE.
>
> - Require FILE__{READ,WRITE,EXECUTE} on /dev/sgx/enclave for simplicity,
> or provide an alternate SGX_IOC_MPROTECT if we want to sidestep the
> FILE__WRITE requirement.
One more thought. EADD (and the equivalent SGX2 flow) could do
security_mmap_file() with a NULL file on the SECINFO permissions, which
would trigger PROCESS_EXECMEM if an enclave attempts to map a page RWX.
> No changes are required to LSMs, SGX1 has a single LSM touchpoint in its
> mmap(), and I *think* the only required userspace change is to mmap()
> PROT_NONE when allocating the enclave's virtual address range.
>
> As for Graphene, it doesn't need extra permissions to run its enclaves,
> it just needs a way to install .sigstruct, which is a generic permissions
> problem and not SGX specific.
>
>
> For SGX2 maybe:
>
> - No additional requirements to map an EAUG'd page as RW page. Not
> aligned with standard MAP_SHARED behavior, but we really don't want
> to require FILE__WRITE, and thus allow writes to .sigstruct.
>
> - Require FILE__EXECMOD on the .sigstruct to map previously writable
> page as executable (which indirectly includes all EAUG'd pages).
> Wiring this up will be a little funky, but we again we don't want
> to require FILE__WRITE on .sigstruct.
>
next prev parent reply other threads:[~2019-05-24 17:55 UTC|newest]
Thread overview: 127+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <8fe520bb-30bd-f246-a3d8-c5443e47a014@intel.com>
[not found] ` <358e9b36-230f-eb18-efdb-b472be8438b4@fortanix.com>
[not found] ` <960B34DE67B9E140824F1DCDEC400C0F4E886094@ORSMSX116.amr.corp.intel.com>
[not found] ` <6da269d8-7ebb-4177-b6a7-50cc5b435cf4@fortanix.com>
[not found] ` <CALCETrWCZQwg-TUCm58DVG43=xCKRsMe1tVHrR8vdt06hf4fWA@mail.gmail.com>
[not found] ` <20190513102926.GD8743@linux.intel.com>
[not found] ` <20190514104323.GA7591@linux.intel.com>
[not found] ` <CALCETrVbgTCnPo=PAq0-KoaRwt--urrPzn==quAJ8wodCpkBkw@mail.gmail.com>
[not found] ` <20190514204527.GC1977@linux.intel.com>
[not found] ` <CALCETrX6aL367mMJh5+Y1Seznfu-AvhPV6P7GkWF4Dhu0GV8cw@mail.gmail.com>
[not found] ` <20190515013031.GF1977@linux.intel.com>
2019-05-15 18:27 ` SGX vs LSM (Re: [PATCH v20 00/28] Intel SGX1 support) Andy Lutomirski
2019-05-15 19:58 ` James Morris
2019-05-15 20:35 ` Andy Lutomirski
2019-05-15 22:46 ` James Morris
2019-05-15 23:13 ` Andy Lutomirski
2019-05-16 3:03 ` Xing, Cedric
2019-05-16 4:40 ` Andy Lutomirski
2019-05-16 22:23 ` Xing, Cedric
2019-05-17 0:35 ` Andy Lutomirski
2019-05-17 1:06 ` Xing, Cedric
2019-05-17 1:21 ` Andy Lutomirski
2019-05-17 16:05 ` Sean Christopherson
2019-05-17 13:53 ` Stephen Smalley
2019-05-17 15:09 ` Sean Christopherson
2019-05-17 16:20 ` Stephen Smalley
2019-05-17 16:24 ` Andy Lutomirski
2019-05-17 16:37 ` Stephen Smalley
2019-05-17 17:12 ` Andy Lutomirski
2019-05-17 18:05 ` Stephen Smalley
2019-05-17 19:20 ` Stephen Smalley
2019-05-17 19:28 ` Sean Christopherson
2019-05-17 20:09 ` Stephen Smalley
2019-05-17 20:14 ` Andy Lutomirski
2019-05-17 20:34 ` Stephen Smalley
2019-05-17 21:36 ` Sean Christopherson
2019-05-17 17:29 ` Sean Christopherson
2019-05-17 17:42 ` Stephen Smalley
2019-05-17 17:50 ` Sean Christopherson
2019-05-17 18:16 ` Stephen Smalley
2019-05-17 17:43 ` Andy Lutomirski
2019-05-17 17:55 ` Sean Christopherson
2019-05-17 18:04 ` Linus Torvalds
2019-05-17 18:21 ` Sean Christopherson
2019-05-17 18:33 ` Linus Torvalds
2019-05-17 18:52 ` Sean Christopherson
2019-05-17 18:53 ` Andy Lutomirski
2019-05-16 7:24 ` James Morris
2019-05-16 21:00 ` Andy Lutomirski
2019-05-20 9:38 ` Dr. Greg
2019-05-15 21:38 ` Sean Christopherson
2019-05-16 1:19 ` Haitao Huang
2019-05-16 5:16 ` Jarkko Sakkinen
2019-05-16 21:02 ` Andy Lutomirski
2019-05-16 22:45 ` Sean Christopherson
2019-05-16 23:29 ` Xing, Cedric
2019-05-20 11:29 ` Jarkko Sakkinen
2019-05-20 11:33 ` Jarkko Sakkinen
2019-05-17 0:03 ` Sean Christopherson
2019-05-17 0:26 ` Andy Lutomirski
2019-05-17 15:41 ` Sean Christopherson
2019-05-20 11:42 ` Jarkko Sakkinen
2019-05-20 11:41 ` Jarkko Sakkinen
2019-05-21 15:19 ` Jarkko Sakkinen
2019-05-21 15:24 ` Jethro Beekman
2019-05-22 13:10 ` Jarkko Sakkinen
2019-05-21 15:51 ` Sean Christopherson
2019-05-22 13:20 ` Jarkko Sakkinen
2019-05-22 13:22 ` Jarkko Sakkinen
2019-05-22 13:56 ` Stephen Smalley
2019-05-22 15:38 ` Sean Christopherson
2019-05-22 22:42 ` Andy Lutomirski
2019-05-23 2:35 ` Sean Christopherson
2019-05-23 10:26 ` Jarkko Sakkinen
2019-05-23 14:17 ` Sean Christopherson
2019-05-23 15:38 ` Andy Lutomirski
2019-05-23 23:40 ` Sean Christopherson
2019-05-24 1:17 ` Andy Lutomirski
2019-05-24 7:24 ` Xing, Cedric
2019-05-24 15:41 ` Stephen Smalley
2019-05-24 16:57 ` Xing, Cedric
2019-05-24 17:42 ` Sean Christopherson
2019-05-24 17:54 ` Andy Lutomirski
2019-05-24 17:56 ` Sean Christopherson
2019-05-24 17:54 ` Sean Christopherson [this message]
2019-05-24 18:34 ` Xing, Cedric
2019-05-24 19:13 ` Sean Christopherson
2019-05-24 19:30 ` Andy Lutomirski
2019-05-24 20:42 ` Xing, Cedric
2019-05-24 21:11 ` Sean Christopherson
2019-05-24 19:37 ` Andy Lutomirski
2019-05-24 20:03 ` Sean Christopherson
2019-05-24 20:58 ` Xing, Cedric
2019-05-24 21:27 ` Andy Lutomirski
2019-05-24 22:41 ` Sean Christopherson
2019-05-24 23:42 ` Andy Lutomirski
2019-05-25 22:40 ` Xing, Cedric
2019-05-26 0:57 ` Andy Lutomirski
2019-05-26 6:09 ` Xing, Cedric
2019-05-28 20:24 ` Sean Christopherson
2019-05-28 20:48 ` Andy Lutomirski
2019-05-28 21:41 ` Sean Christopherson
2019-05-30 5:38 ` Xing, Cedric
2019-05-30 17:21 ` Sean Christopherson
2019-05-29 14:08 ` Stephen Smalley
2019-05-30 6:12 ` Xing, Cedric
2019-05-30 14:22 ` Stephen Smalley
2019-05-30 14:31 ` Andy Lutomirski
2019-05-30 15:04 ` Stephen Smalley
2019-05-30 16:14 ` Andy Lutomirski
2019-05-30 18:01 ` Sean Christopherson
2019-05-30 19:20 ` Andy Lutomirski
2019-05-30 21:16 ` Sean Christopherson
2019-05-30 21:23 ` Andy Lutomirski
2019-05-30 21:36 ` Sean Christopherson
2019-06-03 9:12 ` Dr. Greg
2019-06-03 21:08 ` Jarkko Sakkinen
2019-05-30 21:48 ` Xing, Cedric
2019-05-30 22:24 ` Sean Christopherson
2019-06-03 21:05 ` Jarkko Sakkinen
2019-06-03 20:54 ` Jarkko Sakkinen
2019-06-03 21:23 ` Sean Christopherson
2019-06-04 11:39 ` Jarkko Sakkinen
2019-06-03 21:37 ` Andy Lutomirski
2019-06-03 20:47 ` Jarkko Sakkinen
2019-06-03 20:43 ` Jarkko Sakkinen
2019-05-25 17:31 ` Dr. Greg
2019-05-24 16:43 ` Andy Lutomirski
2019-05-24 17:07 ` Sean Christopherson
2019-05-24 17:51 ` Andy Lutomirski
2019-05-24 14:44 ` Stephen Smalley
2019-05-27 13:48 ` Jarkko Sakkinen
2019-05-23 19:58 ` Sean Christopherson
2019-05-27 13:34 ` Jarkko Sakkinen
2019-05-27 13:38 ` Jarkko Sakkinen
2019-05-23 8:10 ` Jarkko Sakkinen
2019-05-23 8:23 ` Jarkko Sakkinen
2019-05-20 11:36 ` Jarkko Sakkinen
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