1 /*
2 * Copyright 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
17 #include "common/libs/security/keymaster_channel.h"
18
19 #include <cstdlib>
20 #include <memory>
21 #include <ostream>
22 #include <string>
23
24 #include <android-base/logging.h>
25 #include <keymaster/android_keymaster_messages.h>
26 #include <keymaster/mem.h>
27 #include <keymaster/serializable.h>
28
29 #include "common/libs/fs/shared_buf.h"
30
31 namespace cuttlefish {
32
CreateKeymasterMessage(AndroidKeymasterCommand command,bool is_response,size_t payload_size)33 ManagedKeymasterMessage CreateKeymasterMessage(
34 AndroidKeymasterCommand command, bool is_response, size_t payload_size) {
35 auto memory = std::malloc(payload_size + sizeof(keymaster_message));
36 auto message = reinterpret_cast<keymaster_message*>(memory);
37 message->cmd = command;
38 message->is_response = is_response;
39 message->payload_size = payload_size;
40 return ManagedKeymasterMessage(message);
41 }
42
operator ()(keymaster_message * ptr)43 void KeymasterCommandDestroyer::operator()(keymaster_message* ptr) {
44 {
45 keymaster::Eraser(ptr, sizeof(keymaster_message) + ptr->payload_size);
46 }
47 std::free(ptr);
48 }
49
KeymasterChannel(SharedFD input,SharedFD output)50 KeymasterChannel::KeymasterChannel(SharedFD input, SharedFD output)
51 : input_(input), output_(output) {
52 }
53
SendRequest(AndroidKeymasterCommand command,const keymaster::Serializable & message)54 bool KeymasterChannel::SendRequest(
55 AndroidKeymasterCommand command, const keymaster::Serializable& message) {
56 return SendMessage(command, false, message);
57 }
58
SendResponse(AndroidKeymasterCommand command,const keymaster::Serializable & message)59 bool KeymasterChannel::SendResponse(
60 AndroidKeymasterCommand command, const keymaster::Serializable& message) {
61 return SendMessage(command, true, message);
62 }
63
SendMessage(AndroidKeymasterCommand command,bool is_response,const keymaster::Serializable & message)64 bool KeymasterChannel::SendMessage(
65 AndroidKeymasterCommand command,
66 bool is_response,
67 const keymaster::Serializable& message) {
68 auto payload_size = message.SerializedSize();
69 LOG(VERBOSE) << "Sending message with id: " << command << " and size "
70 << payload_size;
71 auto to_send = CreateKeymasterMessage(command, is_response, payload_size);
72 message.Serialize(to_send->payload, to_send->payload + payload_size);
73 auto write_size = payload_size + sizeof(keymaster_message);
74 auto to_send_bytes = reinterpret_cast<const char*>(to_send.get());
75 auto written = WriteAll(output_, to_send_bytes, write_size);
76 if (written != write_size) {
77 LOG(ERROR) << "Could not write Keymaster Message: " << output_->StrError();
78 }
79 return written == write_size;
80 }
81
ReceiveMessage()82 ManagedKeymasterMessage KeymasterChannel::ReceiveMessage() {
83 struct keymaster_message message_header;
84 auto read = ReadExactBinary(input_, &message_header);
85 if (read != sizeof(keymaster_message)) {
86 LOG(ERROR) << "Expected " << sizeof(keymaster_message) << ", received "
87 << read;
88 LOG(ERROR) << "Could not read Keymaster Message: " << input_->StrError();
89 return {};
90 }
91 LOG(VERBOSE) << "Received message with id: " << message_header.cmd
92 << " and size " << message_header.payload_size;
93 auto message = CreateKeymasterMessage(message_header.cmd,
94 message_header.is_response,
95 message_header.payload_size);
96 auto message_bytes = reinterpret_cast<char*>(message->payload);
97 read = ReadExact(input_, message_bytes, message->payload_size);
98 if (read != message->payload_size) {
99 LOG(ERROR) << "Could not read Keymaster Message: " << input_->StrError();
100 return {};
101 }
102 return message;
103 }
104
105 }
106