From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Nathaniel McCallum <npmccallum@redhat.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
X86 ML <x86@kernel.org>,
linux-sgx@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
linux-kselftest@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
asapek@google.com, Borislav Petkov <bp@alien8.de>,
"Xing, Cedric" <cedric.xing@intel.com>,
chenalexchen@google.com, Conrad Parker <conradparker@google.com>,
cyhanish@google.com, Dave Hansen <dave.hansen@intel.com>,
"Huang, Haitao" <haitao.huang@intel.com>,
Josh Triplett <josh@joshtriplett.org>,
"Huang, Kai" <kai.huang@intel.com>,
"Svahn, Kai" <kai.svahn@intel.com>, Keith Moyer <kmoy@google.com>,
Christian Ludloff <ludloff@google.com>,
Andy Lutomirski <luto@kernel.org>,
Neil Horman <nhorman@redhat.com>,
Patrick Uiterwijk <puiterwijk@redhat.com>,
David Rientjes <rientjes@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
yaozhangx@google.com
Subject: Re: [PATCH v36 22/24] selftests/x86: Add a selftest for SGX
Date: Thu, 27 Aug 2020 08:20:51 -0700 [thread overview]
Message-ID: <20200827152051.GB22351@sjchrist-ice> (raw)
In-Reply-To: <CAOASepO-DuQW88hxtAJv5Ki4GNYnkGNz5qK_dTEK_y8roMdPkg@mail.gmail.com>
On Thu, Aug 27, 2020 at 12:47:04AM -0400, Nathaniel McCallum wrote:
> > +int main(int argc, char *argv[], char *envp[])
> > +{
> > + struct sgx_enclave_exception exception;
> > + struct vdso_symtab symtab;
> > + Elf64_Sym *eenter_sym;
> > + uint64_t result = 0;
> > + struct encl encl;
> > + unsigned int i;
> > + void *addr;
> > +
> > + if (!encl_load("test_encl.elf", &encl))
> > + goto err;
> > +
> > + if (!encl_measure(&encl))
> > + goto err;
> > +
> > + if (!encl_build(&encl))
> > + goto err;
> > +
> > + /*
> > + * An enclave consumer only must do this.
> > + */
> > + for (i = 0; i < encl.nr_segments; i++) {
> > + struct encl_segment *seg = &encl.segment_tbl[i];
> > +
> > + addr = mmap((void *)encl.encl_base + seg->offset, seg->size,
> > + seg->prot, MAP_SHARED | MAP_FIXED, encl.fd, 0);
>
> My patch version is a bit behind (v32), but I suspect this still
> applies. I discovered the following by accident.
>
> In the Enarx code base, this invocation succeeds:
> mmap(0x200000000000, 0x1000, PROT_READ | PROT_WRITE, MAP_SHARED |
> MAP_FIXED, sgxfd, 0)
>
> However, this one fails with -EINVAL:
> mmap(0x200000000000, 0x1000, PROT_READ | PROT_WRITE,
> MAP_SHARED_VALIDATE | MAP_FIXED, sgxfd, 0)
>
> From man mmap:
>
> MAP_SHARED_VALIDATE (since Linux 4.15)
> This flag provides the same behavior as MAP_SHARED
> except that MAP_SHARED mappings ignore unknown
> flags in flags. By contrast, when creating a mapping
> using MAP_SHARED_VALIDATE, the kernel veri‐
> fies all passed flags are known and fails the
> mapping with the error EOPNOTSUPP for unknown
> flags. This mapping type is also required to be able to
> use some mapping flags (e.g., MAP_SYNC).
>
> I can try again on a newer patch set tomorrow if need be. But the
> documentation of mmap() doesn't match the behavior I'm seeing. A brief
> look through the patch set didn't turn up anything obvious that could
> be causing this.
This is a bug in sgx_get_unmapped_area(). EPC must be mapped SHARED, and
so MAP_PRIVATE is disallowed. The current check is:
if (flags & MAP_PRIVATE)
return -EINVAL;
and the base "flags" are:
#define MAP_SHARED 0x01 /* Share changes */
#define MAP_PRIVATE 0x02 /* Changes are private */
#define MAP_SHARED_VALIDATE 0x03 /* share + validate extension flags */
which causes the SGX check to interpret MAP_SHARED_VALIDATE as MAP_PRIVATE.
The types are just that, types, not flag modifiers. So the SGX code needs
to be:
if ((flags & MAP_TYPE) == MAP_PRIVATE)
return -EINVAL;
or
unsigned long map_type = (flags & MAP_TYPE);
if (map_type != MAP_SHARED && map_type != MAP_SHARED_VALIDATE)
return -EINVAL;
Side topic, there is at least one existing bug of this nature, in mm/nommu.c.
I'll send a patch for that and look for any other instances of the bad
pattern.
next prev parent reply other threads:[~2020-08-27 15:21 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-16 13:52 [PATCH v36 00/24] Intel SGX foundations Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 01/24] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
2020-08-06 13:13 ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 02/24] x86/cpufeatures: x86/msr: Add Intel SGX Launch Control " Jarkko Sakkinen
2020-08-06 13:14 ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 03/24] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
2020-08-06 13:16 ` Darren Kenny
2020-08-20 15:31 ` Borislav Petkov
2020-08-21 17:35 ` Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 04/24] x86/sgx: Add SGX microarchitectural data structures Jarkko Sakkinen
2020-08-06 13:14 ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 05/24] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2020-08-07 9:37 ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 06/24] x86/cpu/intel: Detect SGX support Jarkko Sakkinen
2020-08-06 13:17 ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 07/24] x86/cpu/intel: Add nosgx kernel parameter Jarkko Sakkinen
2020-08-06 13:18 ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 08/24] x86/sgx: Initialize metadata for Enclave Page Cache (EPC) sections Jarkko Sakkinen
2020-08-06 13:27 ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 09/24] x86/sgx: Add __sgx_alloc_epc_page() and sgx_free_epc_page() Jarkko Sakkinen
2020-08-06 13:29 ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 10/24] mm: Add vm_ops->mprotect() Jarkko Sakkinen
2020-08-06 13:35 ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 11/24] x86/sgx: Add SGX enclave driver Jarkko Sakkinen
2020-08-06 13:59 ` Darren Kenny
2020-08-25 16:44 ` Borislav Petkov
2020-08-26 13:46 ` Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 12/24] x86/sgx: Add SGX_IOC_ENCLAVE_CREATE Jarkko Sakkinen
2020-08-06 15:40 ` Darren Kenny
2020-08-26 14:52 ` Borislav Petkov
2020-08-27 13:24 ` Jarkko Sakkinen
2020-08-27 16:15 ` Borislav Petkov
2020-08-28 23:39 ` Jarkko Sakkinen
2020-08-29 0:21 ` Jarkko Sakkinen
2020-09-01 16:41 ` Haitao Huang
2020-09-04 11:55 ` Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 13/24] x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES Jarkko Sakkinen
2020-08-06 16:29 ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 14/24] x86/sgx: Add SGX_IOC_ENCLAVE_INIT Jarkko Sakkinen
2020-08-06 16:40 ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 15/24] x86/sgx: Allow a limited use of ATTRIBUTE.PROVISIONKEY for attestation Jarkko Sakkinen
2020-08-06 17:00 ` Darren Kenny
2020-08-18 13:30 ` Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 16/24] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 17/24] x86/sgx: ptrace() support for the SGX driver Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 18/24] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 19/24] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 20/24] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2020-07-16 13:53 ` [PATCH v36 21/24] x86/vdso: Implement a vDSO for Intel SGX enclave call Jarkko Sakkinen
2020-08-06 14:55 ` Nathaniel McCallum
2020-08-10 22:23 ` Sean Christopherson
2020-08-11 7:16 ` Jethro Beekman
2020-08-11 14:54 ` Sean Christopherson
2020-08-18 14:52 ` Jarkko Sakkinen
2020-08-18 15:06 ` Jarkko Sakkinen
2020-08-18 15:15 ` Nathaniel McCallum
2020-08-18 16:43 ` Jarkko Sakkinen
2020-08-19 13:33 ` Nathaniel McCallum
2020-08-19 14:00 ` Jethro Beekman
2020-08-19 21:23 ` Jarkko Sakkinen
2020-08-10 23:08 ` Andy Lutomirski
2020-08-10 23:48 ` Sean Christopherson
2020-08-11 0:52 ` Andy Lutomirski
2020-08-11 15:16 ` Andy Lutomirski
2020-08-13 19:38 ` Sean Christopherson
2020-08-17 13:12 ` Nathaniel McCallum
2020-08-17 15:01 ` Andy Lutomirski
2020-08-18 15:15 ` Jarkko Sakkinen
2020-08-20 0:19 ` Andy Lutomirski
2020-08-18 14:26 ` Jarkko Sakkinen
2020-07-16 13:53 ` [PATCH v36 22/24] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2020-08-27 4:47 ` Nathaniel McCallum
2020-08-27 15:20 ` Sean Christopherson [this message]
2020-08-28 23:27 ` Jarkko Sakkinen
2020-07-16 13:53 ` [PATCH v36 23/24] docs: x86/sgx: Document SGX micro architecture and kernel internals Jarkko Sakkinen
2020-07-28 21:35 ` Pavel Machek
2020-08-06 10:21 ` Dr. Greg
2020-08-08 22:18 ` Pavel Machek
2020-08-19 20:55 ` Jarkko Sakkinen
2020-07-16 13:53 ` [PATCH v36 24/24] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
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