tee: optee: do not check memref size on return from Secure World

When Secure World returns, it may have changed the size attribute of the
memory references passed as [in/out] parameters. The GlobalPlatform TEE
Internal Core API specification does not restrict the values that this
size can take. In particular, Secure World may increase the value to be
larger than the size of the input buffer to indicate that it needs more.

Therefore, the size check in optee_from_msg_param() is incorrect and
needs to be removed. This fixes a number of failed test cases in the
GlobalPlatform TEE Initial Configuratiom Test Suite v2_0_0_0-2017_06_09
when OP-TEE is compiled without dynamic shared memory support
(CFG_CORE_DYN_SHM=n).

Suggested-by: Jens Wiklander <[email protected]>
Signed-off-by: Jerome Forissier <[email protected]>

Author: jforissier

drivers/tee/optee/core.c

@@ -80,16 +80,6 @@ int optee_from_msg_param(struct tee_param *params, size_t num_params,
 				return rc;
 			p->u.memref.shm_offs = mp->u.tmem.buf_ptr - pa;
 			p->u.memref.shm = shm;
-
-			/* Check that the memref is covered by the shm object */
-			if (p->u.memref.size) {
-				size_t o = p->u.memref.shm_offs +
-					   p->u.memref.size - 1;
-
-				rc = tee_shm_get_pa(shm, o, NULL);
-				if (rc)
-					return rc;
-			}
 			break;
 		case OPTEE_MSG_ATTR_TYPE_RMEM_INPUT:
 		case OPTEE_MSG_ATTR_TYPE_RMEM_OUTPUT: