Commit 50b822e4 authored by Reinette Chatre's avatar Reinette Chatre Committed by Dave Hansen
Browse files

selftests/sgx: Test faulty enclave behavior 



Removing a page from an initialized enclave involves three steps:
first the user requests changing the page type to SGX_PAGE_TYPE_TRIM
via an ioctl(), on success the ENCLU[EACCEPT] instruction needs to be
run from within the enclave to accept the page removal, finally the
user requests page removal to be completed via an ioctl(). Only after
acceptance (ENCLU[EACCEPT]) from within the enclave can the kernel
remove the page from a running enclave.

Test the behavior when the user's request to change the page type
succeeds, but the ENCLU[EACCEPT] instruction is not run before the
ioctl() requesting page removal is run. This should not be permitted.

Signed-off-by: default avatarReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Acked-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
Link: https://lkml.kernel.org/r/fa5da30ebac108b7517194c3038b52995602b996.1652137848.git.reinette.chatre@intel.com
parent 33c5aac3

tools/testing/selftests/sgx/main.c

+114 −0
Original line number Diff line number Diff line
@@ -1433,4 +1433,118 @@ TEST_F(enclave, tcs_create) 
	munmap(addr, 3 * PAGE_SIZE);

}



/*

 * Ensure sane behavior if user requests page removal, does not run

 * EACCEPT from within enclave but still attempts to finalize page removal

 * with the SGX_IOC_ENCLAVE_REMOVE_PAGES ioctl(). The latter should fail

 * because the removal was not EACCEPTed from within the enclave.

 */

TEST_F(enclave, remove_added_page_no_eaccept)

{

	struct sgx_enclave_remove_pages remove_ioc;

	struct encl_op_get_from_addr get_addr_op;

	struct sgx_enclave_modify_types modt_ioc;

	struct encl_op_put_to_addr put_addr_op;

	unsigned long data_start;

	int ret, errno_save;



	ASSERT_TRUE(setup_test_encl(ENCL_HEAP_SIZE_DEFAULT, &self->encl, _metadata));



	memset(&self->run, 0, sizeof(self->run));

	self->run.tcs = self->encl.encl_base;



	/*

	 * Hardware (SGX2) and kernel support is needed for this test. Start

	 * with check that test has a chance of succeeding.

	 */

	memset(&modt_ioc, 0, sizeof(modt_ioc));

	ret = ioctl(self->encl.fd, SGX_IOC_ENCLAVE_MODIFY_TYPES, &modt_ioc);



	if (ret == -1) {

		if (errno == ENOTTY)

			SKIP(return,

			     "Kernel does not support SGX_IOC_ENCLAVE_MODIFY_TYPES ioctl()");

		else if (errno == ENODEV)

			SKIP(return, "System does not support SGX2");

	}



	/*

	 * Invalid parameters were provided during sanity check,

	 * expect command to fail.

	 */

	EXPECT_EQ(ret, -1);



	/*

	 * Page that will be removed is the second data page in the .data

	 * segment. This forms part of the local encl_buffer within the

	 * enclave.

	 */

	data_start = self->encl.encl_base +

		     encl_get_data_offset(&self->encl) + PAGE_SIZE;



	/*

	 * Sanity check that page at @data_start is writable before

	 * removing it.

	 *

	 * Start by writing MAGIC to test page.

	 */

	put_addr_op.value = MAGIC;

	put_addr_op.addr = data_start;

	put_addr_op.header.type = ENCL_OP_PUT_TO_ADDRESS;



	EXPECT_EQ(ENCL_CALL(&put_addr_op, &self->run, true), 0);



	EXPECT_EEXIT(&self->run);

	EXPECT_EQ(self->run.exception_vector, 0);

	EXPECT_EQ(self->run.exception_error_code, 0);

	EXPECT_EQ(self->run.exception_addr, 0);



	/*

	 * Read memory that was just written to, confirming that data

	 * previously written (MAGIC) is present.

	 */

	get_addr_op.value = 0;

	get_addr_op.addr = data_start;

	get_addr_op.header.type = ENCL_OP_GET_FROM_ADDRESS;



	EXPECT_EQ(ENCL_CALL(&get_addr_op, &self->run, true), 0);



	EXPECT_EQ(get_addr_op.value, MAGIC);

	EXPECT_EEXIT(&self->run);

	EXPECT_EQ(self->run.exception_vector, 0);

	EXPECT_EQ(self->run.exception_error_code, 0);

	EXPECT_EQ(self->run.exception_addr, 0);



	/* Start page removal by requesting change of page type to PT_TRIM */

	memset(&modt_ioc, 0, sizeof(modt_ioc));



	modt_ioc.offset = encl_get_data_offset(&self->encl) + PAGE_SIZE;

	modt_ioc.length = PAGE_SIZE;

	modt_ioc.page_type = SGX_PAGE_TYPE_TRIM;



	ret = ioctl(self->encl.fd, SGX_IOC_ENCLAVE_MODIFY_TYPES, &modt_ioc);

	errno_save = ret == -1 ? errno : 0;



	EXPECT_EQ(ret, 0);

	EXPECT_EQ(errno_save, 0);

	EXPECT_EQ(modt_ioc.result, 0);

	EXPECT_EQ(modt_ioc.count, 4096);



	/* Skip EACCEPT */



	/* Send final ioctl() to complete page removal */

	memset(&remove_ioc, 0, sizeof(remove_ioc));



	remove_ioc.offset = encl_get_data_offset(&self->encl) + PAGE_SIZE;

	remove_ioc.length = PAGE_SIZE;



	ret = ioctl(self->encl.fd, SGX_IOC_ENCLAVE_REMOVE_PAGES, &remove_ioc);

	errno_save = ret == -1 ? errno : 0;



	/* Operation not permitted since EACCEPT was omitted. */

	EXPECT_EQ(ret, -1);

	EXPECT_EQ(errno_save, EPERM);

	EXPECT_EQ(remove_ioc.count, 0);

}



TEST_HARNESS_MAIN