/** * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. * SPDX-License-Identifier: Apache-2.0. */ #include #include "pkcs11_private.h" #include #include #include struct aws_pkcs11_tls_op_handler { /* The custom key operation handler needed for the callbacks */ struct aws_custom_key_op_handler base; struct aws_allocator *alloc; struct aws_pkcs11_lib *lib; /* Use a single PKCS#11 session for all TLS connections on an aws_tls_ctx. * We do this because PKCS#11 tokens may only support a * limited number of sessions (PKCS11-UG-v2.40 section 2.6.7). * If this one shared session turns out to be a severe bottleneck, * we could look into other setups (ex: put session on its own thread, * 1 session per event-loop, 1 session per connection, etc). * * The lock must be held while performing session operations. * Otherwise, it would not be safe for multiple threads to share a * session (PKCS11-UG-v2.40 section 2.6.7). The lock isn't needed for * setup and teardown though, since we ensure nothing parallel is going * on at these times */ struct aws_mutex session_lock; CK_SESSION_HANDLE session_handle; CK_OBJECT_HANDLE private_key_handle; CK_KEY_TYPE private_key_type; }; static void s_aws_custom_key_op_handler_destroy(struct aws_custom_key_op_handler *key_op_handler) { struct aws_pkcs11_tls_op_handler *handler = (struct aws_pkcs11_tls_op_handler *)key_op_handler->impl; if (handler->session_handle != 0) { aws_pkcs11_lib_close_session(handler->lib, handler->session_handle); } aws_mutex_clean_up(&handler->session_lock); aws_pkcs11_lib_release(handler->lib); aws_mem_release(handler->alloc, handler); } /** * Performs the PKCS11 TLS private key operation. This is called automatically when performing a mutual TLS handshake. */ void s_aws_pkcs11_tls_op_handler_do_operation( struct aws_custom_key_op_handler *handler, struct aws_tls_key_operation *operation) { struct aws_pkcs11_tls_op_handler *pkcs11_handler = (struct aws_pkcs11_tls_op_handler *)handler->impl; struct aws_byte_buf output_buf; /* initialized later */ AWS_ZERO_STRUCT(output_buf); /*********** BEGIN CRITICAL SECTION ***********/ aws_mutex_lock(&pkcs11_handler->session_lock); bool success_while_locked = false; switch (aws_tls_key_operation_get_type(operation)) { case AWS_TLS_KEY_OPERATION_DECRYPT: if (aws_pkcs11_lib_decrypt( pkcs11_handler->lib, pkcs11_handler->session_handle, pkcs11_handler->private_key_handle, pkcs11_handler->private_key_type, aws_tls_key_operation_get_input(operation), pkcs11_handler->alloc, &output_buf)) { goto unlock; } break; case AWS_TLS_KEY_OPERATION_SIGN: if (aws_pkcs11_lib_sign( pkcs11_handler->lib, pkcs11_handler->session_handle, pkcs11_handler->private_key_handle, pkcs11_handler->private_key_type, aws_tls_key_operation_get_input(operation), pkcs11_handler->alloc, aws_tls_key_operation_get_digest_algorithm(operation), aws_tls_key_operation_get_signature_algorithm(operation), &output_buf)) { goto unlock; } break; default: AWS_LOGF_ERROR( AWS_LS_IO_PKCS11, "PKCS11 Handler %p: Unknown TLS key operation with value of %u", (void *)handler, aws_tls_key_operation_get_type(operation)); aws_raise_error(AWS_ERROR_INVALID_STATE); goto unlock; } success_while_locked = true; unlock: aws_mutex_unlock(&pkcs11_handler->session_lock); /*********** END CRITICAL SECTION ***********/ if (success_while_locked) { aws_tls_key_operation_complete(operation, aws_byte_cursor_from_buf(&output_buf)); } else { aws_tls_key_operation_complete_with_error(operation, aws_last_error()); } aws_byte_buf_clean_up(&output_buf); } static struct aws_custom_key_op_handler_vtable s_aws_custom_key_op_handler_vtable = { .on_key_operation = s_aws_pkcs11_tls_op_handler_do_operation, }; struct aws_custom_key_op_handler *aws_pkcs11_tls_op_handler_new( struct aws_allocator *allocator, struct aws_pkcs11_lib *pkcs11_lib, const struct aws_byte_cursor *user_pin, const struct aws_byte_cursor *match_token_label, const struct aws_byte_cursor *match_private_key_label, const uint64_t *match_slot_id) { bool success = false; struct aws_pkcs11_tls_op_handler *pkcs11_handler = aws_mem_calloc(allocator, 1, sizeof(struct aws_pkcs11_tls_op_handler)); // Optional data struct aws_string *pkcs_user_pin = NULL; struct aws_string *pkcs_token_label = NULL; struct aws_string *pkcs_private_key_object_label = NULL; aws_ref_count_init( &pkcs11_handler->base.ref_count, &pkcs11_handler->base, (aws_simple_completion_callback *)s_aws_custom_key_op_handler_destroy); pkcs11_handler->base.impl = (void *)pkcs11_handler; pkcs11_handler->base.vtable = &s_aws_custom_key_op_handler_vtable; pkcs11_handler->alloc = allocator; /* pkcs11_lib is required */ if (pkcs11_lib == NULL) { aws_raise_error(AWS_ERROR_INVALID_ARGUMENT); AWS_LOGF_ERROR(AWS_LS_IO_PKCS11, "PKCS11 Handler %p new: PKCS11 library is null", (void *)pkcs11_handler); goto done; } pkcs11_handler->lib = aws_pkcs11_lib_acquire(pkcs11_lib); /* cannot fail */ aws_mutex_init(&pkcs11_handler->session_lock); /* user_pin is optional */ if (user_pin->ptr != NULL) { pkcs_user_pin = aws_string_new_from_cursor(allocator, user_pin); } /* token_label is optional */ if (match_token_label->ptr != NULL) { pkcs_token_label = aws_string_new_from_cursor(allocator, match_token_label); } /* private_key_object_label is optional */ if (match_private_key_label->ptr != NULL) { pkcs_private_key_object_label = aws_string_new_from_cursor(allocator, match_private_key_label); } CK_SLOT_ID slot_id; if (aws_pkcs11_lib_find_slot_with_token(pkcs11_handler->lib, match_slot_id, pkcs_token_label, &slot_id /*out*/)) { goto done; } if (aws_pkcs11_lib_open_session(pkcs11_handler->lib, slot_id, &pkcs11_handler->session_handle)) { goto done; } if (aws_pkcs11_lib_login_user(pkcs11_handler->lib, pkcs11_handler->session_handle, pkcs_user_pin)) { goto done; } if (aws_pkcs11_lib_find_private_key( pkcs11_handler->lib, pkcs11_handler->session_handle, pkcs_private_key_object_label, &pkcs11_handler->private_key_handle /*out*/, &pkcs11_handler->private_key_type /*out*/)) { goto done; } success = true; done: /* CLEANUP */ if (pkcs_user_pin != NULL) { aws_string_destroy_secure(pkcs_user_pin); } if (pkcs_token_label != NULL) { aws_string_destroy(pkcs_token_label); } if (pkcs_private_key_object_label != NULL) { aws_string_destroy(pkcs_private_key_object_label); } if (success) { return &pkcs11_handler->base; } else { aws_custom_key_op_handler_release(&pkcs11_handler->base); return NULL; } }