1 /*
2 * Copyright (C) 2021 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 //! A tool to verify a CompOS signature. It starts a CompOS VM as part of this to retrieve the
18 //! public key. The tool is intended to be run by odsign during boot.
19
20 use android_logger::LogId;
21 use anyhow::{bail, Context, Result};
22 use binder::ProcessState;
23 use clap::{Parser, ValueEnum};
24 use compos_common::compos_client::{ComposClient, VmCpuTopology, VmParameters};
25 use compos_common::odrefresh::{
26 CURRENT_ARTIFACTS_SUBDIR, ODREFRESH_OUTPUT_ROOT_DIR, PENDING_ARTIFACTS_SUBDIR,
27 TEST_ARTIFACTS_SUBDIR,
28 };
29 use compos_common::{
30 COMPOS_DATA_ROOT, CURRENT_INSTANCE_DIR, IDSIG_FILE, IDSIG_MANIFEST_APK_FILE,
31 IDSIG_MANIFEST_EXT_APK_FILE, INSTANCE_IMAGE_FILE, TEST_INSTANCE_DIR,
32 };
33 use log::error;
34 use std::fs::File;
35 use std::io::Read;
36 use std::panic;
37 use std::path::Path;
38
39 const MAX_FILE_SIZE_BYTES: u64 = 100 * 1024;
40
41 #[derive(Parser)]
42 struct Args {
43 /// Type of the VM instance
44 #[clap(long, value_enum)]
45 instance: Instance,
46
47 /// Starts the VM in debug mode
48 #[clap(long, action)]
49 debug: bool,
50 }
51
52 #[derive(ValueEnum, Clone)]
53 enum Instance {
54 Current,
55 Pending,
56 Test,
57 }
58
main()59 fn main() {
60 android_logger::init_once(
61 android_logger::Config::default()
62 .with_tag("compos_verify")
63 .with_min_level(log::Level::Info)
64 .with_log_id(LogId::System), // Needed to log successfully early in boot
65 );
66
67 // Redirect panic messages to logcat.
68 panic::set_hook(Box::new(|panic_info| {
69 error!("{}", panic_info);
70 }));
71
72 if let Err(e) = try_main() {
73 error!("{:?}", e);
74 std::process::exit(1)
75 }
76 }
77
try_main() -> Result<()>78 fn try_main() -> Result<()> {
79 let args = Args::parse();
80 let (instance_dir, artifacts_dir) = match args.instance {
81 Instance::Current => (CURRENT_INSTANCE_DIR, CURRENT_ARTIFACTS_SUBDIR),
82 Instance::Pending => (CURRENT_INSTANCE_DIR, PENDING_ARTIFACTS_SUBDIR),
83 Instance::Test => (TEST_INSTANCE_DIR, TEST_ARTIFACTS_SUBDIR),
84 };
85
86 let instance_dir = Path::new(COMPOS_DATA_ROOT).join(instance_dir);
87 let artifacts_dir = Path::new(ODREFRESH_OUTPUT_ROOT_DIR).join(artifacts_dir);
88
89 if !instance_dir.is_dir() {
90 bail!("{:?} is not a directory", instance_dir);
91 }
92
93 let instance_image = instance_dir.join(INSTANCE_IMAGE_FILE);
94 let idsig = instance_dir.join(IDSIG_FILE);
95 let idsig_manifest_apk = instance_dir.join(IDSIG_MANIFEST_APK_FILE);
96 let idsig_manifest_ext_apk = instance_dir.join(IDSIG_MANIFEST_EXT_APK_FILE);
97
98 let instance_image = File::open(instance_image).context("Failed to open instance image")?;
99
100 let info = artifacts_dir.join("compos.info");
101 let signature = artifacts_dir.join("compos.info.signature");
102
103 let info = read_small_file(&info).context("Failed to read compos.info")?;
104 let signature = read_small_file(&signature).context("Failed to read compos.info signature")?;
105
106 // We need to start the thread pool to be able to receive Binder callbacks
107 ProcessState::start_thread_pool();
108
109 let virtmgr = vmclient::VirtualizationService::new()?;
110 let virtualization_service = virtmgr.connect()?;
111 let vm_instance = ComposClient::start(
112 &*virtualization_service,
113 instance_image,
114 &idsig,
115 &idsig_manifest_apk,
116 &idsig_manifest_ext_apk,
117 &VmParameters {
118 name: String::from("ComposVerify"),
119 cpu_topology: VmCpuTopology::OneCpu, // This VM runs very little work at boot
120 debug_mode: args.debug,
121 ..Default::default()
122 },
123 )?;
124
125 let service = vm_instance.connect_service()?;
126 let public_key = service.getPublicKey().context("Getting public key");
127
128 vm_instance.shutdown(service);
129
130 if !compos_verify_native::verify(&public_key?, &signature, &info) {
131 bail!("Signature verification failed");
132 }
133
134 Ok(())
135 }
136
read_small_file(file: &Path) -> Result<Vec<u8>>137 fn read_small_file(file: &Path) -> Result<Vec<u8>> {
138 let mut file = File::open(file)?;
139 if file.metadata()?.len() > MAX_FILE_SIZE_BYTES {
140 bail!("File is too big");
141 }
142 let mut data = Vec::new();
143 file.read_to_end(&mut data)?;
144 Ok(data)
145 }
146
147 #[cfg(test)]
148 mod tests {
149 use super::*;
150 use clap::CommandFactory;
151
152 #[test]
verify_args()153 fn verify_args() {
154 // Check that the command parsing has been configured in a valid way.
155 Args::command().debug_assert();
156 }
157 }
158