From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Andy Lutomirski <luto@kernel.org>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>,
Cedric Xing <cedric.xing@intel.com>,
Stephen Smalley <sds@tycho.nsa.gov>,
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, Jethro Beekman <jethro@fortanix.com>,
Dave Hansen <dave.hansen@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Linus Torvalds <torvalds@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
linux-sgx@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
nhorman@redhat.com, npmccallum@redhat.com,
Serge Ayoun <serge.ayoun@intel.com>,
Shay Katz-zamir <shay.katz-zamir@intel.com>,
Haitao Huang <haitao.huang@intel.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Kai Svahn <kai.svahn@intel.com>, Borislav Petkov <bp@alien8.de>,
Josh Triplett <josh@joshtriplett.org>,
Kai Huang <kai.huang@intel.com>,
David Rientjes <rientjes@google.com>,
William Roberts <william.c.roberts@intel.com>,
Philip Tricca <philip.b.tricca@intel.com>
Subject: Re: [RFC PATCH 2/9] x86/sgx: Do not naturally align MAP_FIXED address
Date: Wed, 5 Jun 2019 18:15:24 +0300 [thread overview]
Message-ID: <20190605151524.GJ11331@linux.intel.com> (raw)
In-Reply-To: <CALCETrVe0jhAWAFmx+NFEjJcijSJv2LDVC7cUXi0w99kNKjh_g@mail.gmail.com>
On Tue, Jun 04, 2019 at 01:16:04PM -0700, Andy Lutomirski wrote:
> On Tue, Jun 4, 2019 at 4:50 AM Jarkko Sakkinen
> <jarkko.sakkinen@linux.intel.com> wrote:
> >
> > On Fri, May 31, 2019 at 04:31:52PM -0700, Sean Christopherson wrote:
> > > SGX enclaves have an associated Enclave Linear Range (ELRANGE) that is
> > > tracked and enforced by the CPU using a base+mask approach, similar to
> > > how hardware range registers such as the variable MTRRs. As a result,
> > > the ELRANGE must be naturally sized and aligned.
> > >
> > > To reduce boilerplate code that would be needed in every userspace
> > > enclave loader, the SGX driver naturally aligns the mmap() address and
> > > also requires the range to be naturally sized. Unfortunately, SGX fails
> > > to grant a waiver to the MAP_FIXED case, e.g. incorrectly rejects mmap()
> > > if userspace is attempting to map a small slice of an existing enclave.
> > >
> > > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> >
> > Why you want to allow mmap() to be called multiple times? mmap() could
> > be allowed only once with PROT_NONE and denied afterwards. Is this for
> > sending fd to another process that would map already existing enclave?
> >
> > I don't see any checks for whether the is enclave underneath. Also, I
> > think that in all cases mmap() callback should allow only PROT_NONE
> > as permissions for clarity even if it could called multiple times.
> >
>
> What's the advantage to only allowing PROT_NONE? The idea here is to
> allow a PROT_NONE map followed by some replacemets that overlay it for
> the individual segments. Admittedly, mprotect() can do the same
> thing, but disallowing mmap() seems at least a bit surprising.
I was merely wondering if it is specifically for the application where a
client process would mmap(MAP_FIXED) an enclave created by a server
process.
/Jarkko
next prev parent reply other threads:[~2019-06-05 15:15 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-31 23:31 [RFC PATCH 0/9] security: x86/sgx: SGX vs. LSM Sean Christopherson
2019-05-31 23:31 ` [RFC PATCH 1/9] x86/sgx: Remove unused local variable in sgx_encl_release() Sean Christopherson
2019-06-04 11:41 ` Jarkko Sakkinen
2019-05-31 23:31 ` [RFC PATCH 2/9] x86/sgx: Do not naturally align MAP_FIXED address Sean Christopherson
2019-06-04 11:49 ` Jarkko Sakkinen
2019-06-04 20:16 ` Andy Lutomirski
2019-06-04 22:10 ` Xing, Cedric
2019-06-05 14:08 ` Sean Christopherson
2019-06-05 15:17 ` Jarkko Sakkinen
2019-06-05 20:14 ` Andy Lutomirski
2019-06-06 15:37 ` Jarkko Sakkinen
2019-06-13 13:48 ` Jarkko Sakkinen
2019-06-13 16:47 ` Xing, Cedric
2019-06-13 17:14 ` Sean Christopherson
2019-06-14 15:18 ` Jarkko Sakkinen
2019-06-05 15:15 ` Jarkko Sakkinen [this message]
2019-05-31 23:31 ` [RFC PATCH 3/9] x86/sgx: Allow userspace to add multiple pages in single ioctl() Sean Christopherson
2019-06-03 6:26 ` Xing, Cedric
2019-06-03 20:08 ` Sean Christopherson
2019-06-03 20:39 ` Sean Christopherson
2019-06-03 23:45 ` Xing, Cedric
2019-06-04 0:54 ` Sean Christopherson
2019-06-04 20:18 ` Andy Lutomirski
2019-06-04 22:02 ` Xing, Cedric
2019-06-03 20:14 ` Dave Hansen
2019-06-03 20:37 ` Sean Christopherson
2019-06-03 20:39 ` Dave Hansen
2019-06-03 23:48 ` Xing, Cedric
2019-06-04 0:55 ` Sean Christopherson
2019-06-04 11:55 ` Jarkko Sakkinen
2019-05-31 23:31 ` [RFC PATCH 4/9] mm: Introduce vm_ops->mprotect() Sean Christopherson
2019-06-03 6:27 ` Xing, Cedric
2019-06-04 12:24 ` Jarkko Sakkinen
2019-06-04 14:51 ` Andy Lutomirski
2019-05-31 23:31 ` [RFC PATCH 5/9] x86/sgx: Restrict mapping without an enclave page to PROT_NONE Sean Christopherson
2019-06-03 6:28 ` Xing, Cedric
2019-06-04 15:32 ` Jarkko Sakkinen
2019-05-31 23:31 ` [RFC PATCH 6/9] x86/sgx: Require userspace to provide allowed prots to ADD_PAGES Sean Christopherson
2019-06-03 6:28 ` Xing, Cedric
2019-06-04 16:23 ` Jarkko Sakkinen
2019-06-04 16:45 ` Sean Christopherson
2019-06-05 15:06 ` Jarkko Sakkinen
2019-06-04 20:23 ` Andy Lutomirski
2019-06-05 11:10 ` Ayoun, Serge
2019-06-05 23:58 ` Sean Christopherson
2019-05-31 23:31 ` [RFC PATCH 7/9] x86/sgx: Enforce noexec filesystem restriction for enclaves Sean Christopherson
2019-06-03 6:29 ` Xing, Cedric
2019-06-04 20:26 ` Andy Lutomirski
2019-06-04 16:25 ` Jarkko Sakkinen
2019-06-04 20:25 ` Andy Lutomirski
2019-06-04 20:34 ` Sean Christopherson
2019-06-04 21:54 ` Xing, Cedric
2019-06-05 15:10 ` Jarkko Sakkinen
2019-06-06 1:01 ` Sean Christopherson
2019-05-31 23:31 ` [RFC PATCH 8/9] LSM: x86/sgx: Introduce ->enclave_load() hook for Intel SGX Sean Christopherson
2019-06-03 6:28 ` Xing, Cedric
2019-06-03 14:19 ` Stephen Smalley
2019-06-03 14:42 ` Sean Christopherson
2019-06-03 18:38 ` Stephen Smalley
2019-06-03 18:45 ` Dave Hansen
2019-06-04 20:29 ` Andy Lutomirski
2019-06-04 20:36 ` Sean Christopherson
2019-06-04 21:43 ` Xing, Cedric
2019-06-06 2:04 ` Sean Christopherson
2019-05-31 23:31 ` [RFC PATCH 9/9] security/selinux: Add enclave_load() implementation Sean Christopherson
2019-06-03 15:01 ` Stephen Smalley
2019-06-03 15:50 ` Sean Christopherson
2019-06-02 7:29 ` [RFC PATCH 0/9] security: x86/sgx: SGX vs. LSM Xing, Cedric
2019-06-03 17:15 ` Sean Christopherson
2019-06-03 18:30 ` Xing, Cedric
2019-06-04 1:36 ` Sean Christopherson
2019-06-04 15:33 ` Stephen Smalley
2019-06-04 16:30 ` Sean Christopherson
2019-06-04 21:38 ` Xing, Cedric
2019-06-03 17:47 ` Stephen Smalley
2019-06-03 18:02 ` Xing, Cedric
2019-06-04 11:15 ` Jarkko Sakkinen
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