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From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: linux-sgx@vger.kernel.org, Dave Hansen <dave.hansen@intel.com>,
	Cedric Xing <cedric.xing@intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Jethro Beekman <jethro@fortanix.com>,
	"Dr . Greg Wettstein" <greg@enjellic.com>,
	Stephen Smalley <sds@tycho.nsa.gov>
Subject: [RFC PATCH v3 03/12] selftests: x86/sgx: Mark the enclave loader as not needing an exec stack
Date: Mon, 17 Jun 2019 15:24:29 -0700	[thread overview]
Message-ID: <20190617222438.2080-4-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20190617222438.2080-1-sean.j.christopherson@intel.com>

The SGX enclave loader doesn't need an executable stack, but linkers
will assume it does due to the lack of .note.GNU-stack sections in the
loader's assembly code.  As a result, the kernel tags the loader as
having "read implies exec", and so adds PROT_EXEC to all mmap()s, even
those for mapping EPC regions.  This will cause problems in the future
when userspace needs to explicit state a page's protection bits when the
page is added to an enclave, e.g. adding TCS pages as R+W will cause
mmap() to fail when the kernel tacks on +X.

Explicitly tell the linker that an executable stack is not needed.
Alternatively, each .S file could add .note.GNU-stack, but the loader
should never need an executable stack so zap it in one fell swoop.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 tools/testing/selftests/x86/sgx/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/x86/sgx/Makefile b/tools/testing/selftests/x86/sgx/Makefile
index 1fd6f2708e81..10136b73096b 100644
--- a/tools/testing/selftests/x86/sgx/Makefile
+++ b/tools/testing/selftests/x86/sgx/Makefile
@@ -2,7 +2,7 @@ top_srcdir = ../../../../..
 
 include ../../lib.mk
 
-HOST_CFLAGS := -Wall -Werror -g $(INCLUDES) -fPIC
+HOST_CFLAGS := -Wall -Werror -g $(INCLUDES) -fPIC -z noexecstack
 ENCL_CFLAGS := -Wall -Werror -static -nostdlib -nostartfiles -fPIC \
 	       -fno-stack-protector -mrdrnd $(INCLUDES)
 
-- 
2.21.0


  parent reply	other threads:[~2019-06-17 22:24 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-17 22:24 [RFC PATCH v3 00/12] security: x86/sgx: SGX vs. LSM, round 3 Sean Christopherson
2019-06-17 22:24 ` [RFC PATCH v3 01/12] x86/sgx: Add mm to enclave at mmap() Sean Christopherson
2019-06-17 22:32   ` Dave Hansen
2019-06-17 23:42   ` Andy Lutomirski
2019-06-18 14:11     ` Sean Christopherson
2019-06-18 16:06       ` Sean Christopherson
2019-06-19 12:56   ` Jarkko Sakkinen
2019-06-19 13:00     ` Jarkko Sakkinen
2019-06-20 20:09       ` Jarkko Sakkinen
2019-06-17 22:24 ` [RFC PATCH v3 02/12] x86/sgx: Do not naturally align MAP_FIXED address Sean Christopherson
2019-06-19 13:24   ` Jarkko Sakkinen
2019-06-19 14:08     ` Sean Christopherson
2019-06-20 22:07       ` Jarkko Sakkinen
2019-06-17 22:24 ` Sean Christopherson [this message]
2019-06-17 22:24 ` [RFC PATCH v3 04/12] x86/sgx: Require userspace to define enclave pages' protection bits Sean Christopherson
2019-06-19 14:43   ` Jarkko Sakkinen
2019-06-19 15:20     ` Sean Christopherson
2019-06-20 22:17       ` Jarkko Sakkinen
2019-07-07 19:08         ` Sean Christopherson
2019-07-08 15:23           ` Jarkko Sakkinen
2019-07-08 16:19             ` Sean Christopherson
2019-07-09 16:06               ` Jarkko Sakkinen
2019-07-10 17:25                 ` Sean Christopherson
2019-07-15 22:29                   ` Andy Lutomirski
2019-08-01 16:38                     ` Jarkko Sakkinen
2019-08-04 22:20                       ` Andy Lutomirski
2019-08-05 20:51                         ` Jarkko Sakkinen
2019-08-05 21:30                           ` Andy Lutomirski
2019-08-07 18:51                             ` Jarkko Sakkinen
2019-06-17 22:24 ` [RFC PATCH v3 05/12] x86/sgx: Enforce noexec filesystem restriction for enclaves Sean Christopherson
2019-06-19 14:46   ` Jarkko Sakkinen
2019-06-17 22:24 ` [RFC PATCH v3 06/12] mm: Introduce vm_ops->may_mprotect() Sean Christopherson
2019-06-17 22:24 ` [RFC PATCH v3 07/12] LSM: x86/sgx: Introduce ->enclave_map() hook for Intel SGX Sean Christopherson
2019-06-17 22:24 ` [RFC PATCH v3 08/12] security/selinux: Require SGX_EXECMEM to map enclave page WX Sean Christopherson
2019-06-17 22:24 ` [RFC PATCH v3 09/12] LSM: x86/sgx: Introduce ->enclave_load() hook for Intel SGX Sean Christopherson
2019-06-19 14:56   ` Jarkko Sakkinen
2019-06-19 21:13     ` James Morris
2019-06-20  9:28       ` Dr. Greg
2019-06-20 22:22       ` Jarkko Sakkinen
2019-06-23 17:16       ` Dr. Greg
2019-06-26 20:39         ` James Morris
2019-06-17 22:24 ` [RFC PATCH v3 10/12] security/selinux: Add enclave_load() implementation Sean Christopherson
2019-06-18 14:49   ` Stephen Smalley
2019-06-19 20:59     ` Sean Christopherson
2019-06-17 22:24 ` [RFC PATCH v3 11/12] security/apparmor: " Sean Christopherson
2019-06-17 22:24 ` [RFC PATCH v3 12/12] LSM: x86/sgx: Show line of sight to LSM support SGX2's EAUG Sean Christopherson
2019-06-18 13:38 ` [RFC PATCH v3 00/12] security: x86/sgx: SGX vs. LSM, round 3 Stephen Smalley
2019-06-18 13:55   ` Sean Christopherson
2019-06-18 15:13     ` Stephen Smalley
2019-06-25 16:29 ` Jarkko Sakkinen

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