1//
2// Copyright (C) 2015 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
17#include "tpm_manager/server/tpm_status_impl.h"
18
19#include <vector>
20
21#include <base/logging.h>
22#include <trousers/tss.h>
23#include <trousers/trousers.h>  // NOLINT(build/include_alpha)
24
25namespace tpm_manager {
26
27// Minimum size of TPM_DA_INFO struct.
28const size_t kMinimumDaInfoSize = 21;
29
30bool TpmStatusImpl::IsTpmEnabled() {
31  if (!is_enable_initialized_) {
32    RefreshOwnedEnabledInfo();
33  }
34  return is_enabled_;
35}
36
37bool TpmStatusImpl::IsTpmOwned() {
38  if (!is_owned_) {
39    RefreshOwnedEnabledInfo();
40  }
41  return is_owned_;
42}
43
44bool TpmStatusImpl::GetDictionaryAttackInfo(int* counter,
45                                            int* threshold,
46                                            bool* lockout,
47                                            int* seconds_remaining) {
48  std::string capability_data;
49  if (!GetCapability(TSS_TPMCAP_DA_LOGIC, TPM_ET_KEYHANDLE,
50                     &capability_data, nullptr) ||
51      capability_data.size() < kMinimumDaInfoSize) {
52    LOG(ERROR) << "Error getting tpm capability data.";
53    return false;
54  }
55  if (static_cast<uint16_t>(capability_data[1]) == TPM_TAG_DA_INFO) {
56    TPM_DA_INFO da_info;
57    uint64_t offset = 0;
58    std::vector<BYTE> bytes(capability_data.begin(), capability_data.end());
59    Trspi_UnloadBlob_DA_INFO(&offset, bytes.data(), &da_info);
60    if (counter) { *counter = da_info.currentCount; }
61    if (threshold) { *threshold = da_info.thresholdCount; }
62    if (lockout) { *lockout = (da_info.state == TPM_DA_STATE_ACTIVE); }
63    if (seconds_remaining) { *seconds_remaining = da_info.actionDependValue; }
64  }
65  return true;
66}
67
68void TpmStatusImpl::RefreshOwnedEnabledInfo() {
69  TSS_RESULT result;
70  std::string capability_data;
71  if (!GetCapability(TSS_TPMCAP_PROPERTY, TSS_TPMCAP_PROP_OWNER,
72                     &capability_data, &result)) {
73    if (ERROR_CODE(result) == TPM_E_DISABLED) {
74      is_enable_initialized_ = true;
75      is_enabled_ = false;
76    }
77  } else {
78    is_enable_initialized_ = true;
79    is_enabled_ = true;
80    // |capability_data| should be populated with a TSS_BOOL which is true iff
81    // the Tpm is owned.
82    if (capability_data.size() != sizeof(TSS_BOOL)) {
83      LOG(ERROR) << "Error refreshing Tpm ownership information.";
84      return;
85    }
86    is_owned_ = (capability_data[0] != 0);
87  }
88}
89
90bool TpmStatusImpl::GetCapability(uint32_t capability,
91                                  uint32_t sub_capability,
92                                  std::string* data,
93                                  TSS_RESULT* tpm_result) {
94  CHECK(data);
95  TSS_HTPM tpm_handle = tpm_connection_.GetTpm();
96  if (tpm_handle == 0) {
97    return false;
98  }
99  uint32_t length = 0;
100  trousers::ScopedTssMemory buf(tpm_connection_.GetContext());
101  TSS_RESULT result = Tspi_TPM_GetCapability(
102      tpm_handle, capability, sizeof(uint32_t),
103      reinterpret_cast<BYTE*>(&sub_capability),
104      &length, buf.ptr());
105  if (tpm_result) {
106    *tpm_result = result;
107  }
108  if (TPM_ERROR(result)) {
109    LOG(ERROR) << "Error getting TPM capability data.";
110    return false;
111  }
112  data->assign(buf.value(), buf.value() + length);
113  return true;
114}
115
116}  // namespace tpm_manager
117