1 //
2 // Copyright (C) 2020 The Android Open Source Project
3 //
4 // Licensed under the Apache License, Version 2.0 (the "License");
5 // you may not use this file except in compliance with the License.
6 // You may obtain a copy of the License at
7 //
8 // http://www.apache.org/licenses/LICENSE-2.0
9 //
10 // Unless required by applicable law or agreed to in writing, software
11 // distributed under the License is distributed on an "AS IS" BASIS,
12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 // See the License for the specific language governing permissions and
14 // limitations under the License.
15
16 #include "tpm_resource_manager.h"
17
18 #include <android-base/logging.h>
19 #include <tss2/tss2_rc.h>
20
ObjectSlot(TpmResourceManager * resource_manager)21 TpmResourceManager::ObjectSlot::ObjectSlot(TpmResourceManager* resource_manager)
22 : ObjectSlot(resource_manager, ESYS_TR_NONE) {
23 }
24
ObjectSlot(TpmResourceManager * resource_manager,ESYS_TR resource)25 TpmResourceManager::ObjectSlot::ObjectSlot(TpmResourceManager* resource_manager,
26 ESYS_TR resource)
27 : resource_manager_(resource_manager), resource_(resource) {
28 LOG(VERBOSE) << "Resource allocated";
29 }
30
~ObjectSlot()31 TpmResourceManager::ObjectSlot::~ObjectSlot() {
32 if (resource_ != ESYS_TR_NONE) {
33 LOG(VERBOSE) << "Freeing resource";
34 auto rc = Esys_FlushContext(resource_manager_->esys_, resource_);
35 if (rc != TPM2_RC_SUCCESS) {
36 LOG(ERROR) << "Esys_FlushContext failed: " << Tss2_RC_Decode(rc)
37 << "(" << rc << ")";
38 }
39 } else {
40 LOG(VERBOSE) << "Resource is NONE";
41 }
42 resource_manager_->used_slots_--;
43 }
44
get()45 ESYS_TR TpmResourceManager::ObjectSlot::get() {
46 return resource_;
47 }
48
set(ESYS_TR resource)49 void TpmResourceManager::ObjectSlot::set(ESYS_TR resource) {
50 resource_ = resource;
51 }
52
TpmResourceManager(ESYS_CONTEXT * esys)53 TpmResourceManager::TpmResourceManager(ESYS_CONTEXT* esys)
54 : esys_(esys), maximum_object_slots_(3), used_slots_(0) {
55 // TODO(b/158791154): Find maximum_object_slots dynamically using
56 // TPM2_GetCapability. Now equal to MAX_LOADED_OBJECTS from TpmProfile.h.
57 }
58
~TpmResourceManager()59 TpmResourceManager::~TpmResourceManager() {
60 if (used_slots_ > 0) {
61 LOG(FATAL) << "Outstanding TpmResourceManager::ObjectSlot instances. "
62 "These hold a dangling pointer to this instance.";
63 }
64 }
65
Esys()66 ESYS_CONTEXT* TpmResourceManager::Esys() {
67 return esys_;
68 }
69
ReserveSlot()70 TpmObjectSlot TpmResourceManager::ReserveSlot() {
71 auto slot_num = used_slots_.fetch_add(1);
72 if (slot_num >= maximum_object_slots_) {
73 used_slots_--;
74 return nullptr;
75 }
76 return TpmObjectSlot{new ObjectSlot(this)};
77 }
78