1 /*
2 * Copyright 2022 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 use anyhow::{bail, Context, Result};
18 use std::io::Write;
19 use std::process::{Command, Stdio};
20
21 const COMPOS_KEY_HELPER_PATH: &str = "/apex/com.android.compos/bin/compos_key_helper";
22
get_public_key() -> Result<Vec<u8>>23 pub fn get_public_key() -> Result<Vec<u8>> {
24 get_data_from_helper("public_key")
25 }
26
get_attestation_chain() -> Result<Vec<u8>>27 pub fn get_attestation_chain() -> Result<Vec<u8>> {
28 get_data_from_helper("bcc")
29 }
30
get_data_from_helper(command: &str) -> Result<Vec<u8>>31 fn get_data_from_helper(command: &str) -> Result<Vec<u8>> {
32 let child = Command::new(COMPOS_KEY_HELPER_PATH)
33 .arg(command)
34 .stdin(Stdio::null())
35 .stdout(Stdio::piped())
36 .stderr(Stdio::piped())
37 .spawn()?;
38 let result = child.wait_with_output()?;
39 if !result.status.success() {
40 bail!("Helper failed: {:?}", result);
41 }
42 Ok(result.stdout)
43 }
44
sign(data: &[u8]) -> Result<Vec<u8>>45 pub fn sign(data: &[u8]) -> Result<Vec<u8>> {
46 let mut child = Command::new(COMPOS_KEY_HELPER_PATH)
47 .arg("sign")
48 .stdin(Stdio::piped())
49 .stdout(Stdio::piped())
50 .stderr(Stdio::piped())
51 .spawn()?;
52
53 // No output is written until the entire input is consumed, so this shouldn't deadlock.
54 let result =
55 child.stdin.take().unwrap().write_all(data).context("Failed to write data to be signed");
56 if result.is_ok() {
57 let result = child.wait_with_output()?;
58 if !result.status.success() {
59 bail!("Helper failed: {}", result.status);
60 }
61 return Ok(result.stdout);
62 }
63
64 // The child may have exited already, but if it hasn't then we need to make sure it does.
65 let _ignored = child.kill();
66
67 let result = result.with_context(|| match child.wait() {
68 Ok(exit_status) => format!("Child exited: {}", exit_status),
69 Err(wait_err) => format!("Wait for child failed: {:?}", wait_err),
70 });
71 Err(result.unwrap_err())
72 }
73