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Tn/unsafe handling #1114

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Tn/unsafe handling #1114

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54e7491
Add/remove unsafe depending on whether the function actually does uns…
Niederb Dec 1, 2022
0d00624
Refactor the code into a safe and an unsafe function
Niederb Dec 1, 2022
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4 changes: 2 additions & 2 deletions enclave-runtime/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -257,7 +257,7 @@ fn sidechain_rpc_int(request: &str) -> Result<String> {
/// (parentchain components) have been initialized (because we need the parentchain
/// block import dispatcher).
#[no_mangle]
pub unsafe extern "C" fn init_enclave_sidechain_components() -> sgx_status_t {
pub extern "C" fn init_enclave_sidechain_components() -> sgx_status_t {
if let Err(e) = initialization::init_enclave_sidechain_components() {
error!("Failed to initialize sidechain components: {:?}", e);
return sgx_status_t::SGX_ERROR_UNEXPECTED
Expand Down Expand Up @@ -387,7 +387,7 @@ fn dispatch_parentchain_blocks_for_import<WorkerModeProvider: ProvideWorkerMode>
/// This trigger is only useful in combination with a `TriggeredDispatcher` and sidechain. In case no
/// sidechain and the `ImmediateDispatcher` are used, this function is obsolete.
#[no_mangle]
pub unsafe extern "C" fn trigger_parentchain_block_import() -> sgx_status_t {
pub extern "C" fn trigger_parentchain_block_import() -> sgx_status_t {
match internal_trigger_parentchain_block_import() {
Ok(()) => sgx_status_t::SGX_SUCCESS,
Err(e) => {
Expand Down
2 changes: 1 addition & 1 deletion enclave-runtime/src/tls_ra/tls_ra_server.rs
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Expand Up @@ -152,7 +152,7 @@ where
}

#[no_mangle]
pub unsafe extern "C" fn run_state_provisioning_server(
pub extern "C" fn run_state_provisioning_server(
socket_fd: c_int,
sign_type: sgx_quote_sign_type_t,
skip_ra: c_int,
Expand Down
2 changes: 1 addition & 1 deletion enclave-runtime/src/top_pool_execution.rs
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Expand Up @@ -67,7 +67,7 @@ use sp_runtime::{
use std::{sync::Arc, time::Instant, vec::Vec};

#[no_mangle]
pub unsafe extern "C" fn execute_trusted_calls() -> sgx_status_t {
pub extern "C" fn execute_trusted_calls() -> sgx_status_t {
if let Err(e) = execute_top_pool_trusted_calls_internal() {
return e.into()
}
Expand Down
2 changes: 1 addition & 1 deletion service/src/ocall_bridge/ffi/get_ias_socket.rs
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Expand Up @@ -22,7 +22,7 @@ use sgx_types::{c_int, sgx_status_t};
use std::sync::Arc;

#[no_mangle]
pub extern "C" fn ocall_get_ias_socket(ret_fd: *mut c_int) -> sgx_status_t {
pub unsafe extern "C" fn ocall_get_ias_socket(ret_fd: *mut c_int) -> sgx_status_t {
get_ias_socket(ret_fd, Bridge::get_ra_api()) // inject the RA API (global state)
}

Expand Down
45 changes: 20 additions & 25 deletions service/src/ocall_bridge/ffi/get_update_info.rs
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Expand Up @@ -16,46 +16,41 @@

*/

use crate::ocall_bridge::bridge_api::{Bridge, RemoteAttestationBridge};
use crate::ocall_bridge::bridge_api::{Bridge, OCallBridgeResult, RemoteAttestationBridge};
use log::*;
use sgx_types::{sgx_platform_info_t, sgx_status_t, sgx_update_info_bit_t};
use std::sync::Arc;

#[no_mangle]
pub extern "C" fn ocall_get_update_info(
pub unsafe extern "C" fn ocall_get_update_info(
p_platform_blob: *const sgx_platform_info_t,
enclave_trusted: i32,
p_update_info: *mut sgx_update_info_bit_t,
) -> sgx_status_t {
get_update_info(
p_platform_blob,
if p_platform_blob.is_null() || p_update_info.is_null() {
return sgx_status_t::SGX_ERROR_INVALID_PARAMETER
}
Comment on lines +30 to +32
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In general, I think I like your proposal, and agree with it.

The only thing that I wonder; the teaclave examples don't check for null pointers in their sample code either, so I wonder if the overall construct with rust FFI and .edl files gives guarantees such that these function args can't be null?

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Hmm, yeah you are right regarding the teaclave example, but I don't see how they could guarantee that the arguments are never null. It can be a valid use-case to pass a null into a function so it cannot be enforced in general.

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I could imagine that the edger8r does enforce it. As the .edl files are strongly typed, the edger8r might enforce that a pointer to something does, in fact, always point to a valid object of said type. I am not sure about this though, but I found this very interesting reference to the edger8r.

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There is only one place in the code samples where they check for null pointer on the v2.0.0-preview branch:
https://github.com/apache/incubator-teaclave-sgx-sdk/blob/v2.0.0-preview/samplecode/httpreq/enclave/src/lib.rs#L33:L38

(There are some checks on the current master branch as well)

I did not find anything related to explicit null checking in https://download.01.org/intel-sgx/latest/linux-latest/docs/Intel_SGX_Developer_Reference_Linux_2.18_Open_Source.pdf

I think it is worth to asking it on openenclave though just to have a confirmation.

let platform_blob = unsafe { *p_platform_blob };

let update_info_result = match get_update_info(
&platform_blob,
enclave_trusted,
p_update_info,
Bridge::get_ra_api(), // inject the RA API (global state)
)
) {
Ok(update_info_result) => update_info_result,
Err(e) => return e.into(),
};
unsafe {
*p_update_info = update_info_result;
}
sgx_status_t::SGX_SUCCESS
}

fn get_update_info(
p_platform_blob: *const sgx_platform_info_t,
platform_blob: &sgx_platform_info_t,
enclave_trusted: i32,
p_update_info: *mut sgx_update_info_bit_t,
ra_api: Arc<dyn RemoteAttestationBridge>,
) -> sgx_status_t {
) -> OCallBridgeResult<sgx_update_info_bit_t> {
debug!(" Entering ocall_get_update_info");

let platform_blob = unsafe { *p_platform_blob };

let update_info_result = match ra_api.get_update_info(platform_blob, enclave_trusted) {
Ok(r) => r,
Err(e) => {
error!("[-] Failed to get update info: {:?}", e);
return e.into()
},
};

unsafe {
*p_update_info = update_info_result;
}

sgx_status_t::SGX_SUCCESS
ra_api.get_update_info(*platform_blob, enclave_trusted)
}