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|
use super::error::CertError;
use crate::command::Command;
use certificate::{KeyCertPair, NewCertificateConfig};
use std::{
fs::{File, OpenOptions},
io::prelude::*,
path::Path,
};
use tedge_config::*;
use tedge_utils::paths::{set_permission, validate_parent_dir_exists};
/// Create a self-signed device certificate
pub struct CreateCertCmd {
/// The device identifier
pub id: String,
/// The path where the device certificate will be stored
pub cert_path: FilePath,
/// The path where the device private key will be stored
pub key_path: FilePath,
}
impl Command for CreateCertCmd {
fn description(&self) -> String {
format!("create a test certificate for the device {}.", self.id)
}
fn execute(&self) -> anyhow::Result<()> {
let config = NewCertificateConfig::default();
let () = self.create_test_certificate(&config)?;
Ok(())
}
}
impl CreateCertCmd {
fn create_test_certificate(&self, config: &NewCertificateConfig) -> Result<(), CertError> {
validate_parent_dir_exists(&self.cert_path).map_err(CertError::CertPathError)?;
validate_parent_dir_exists(&self.key_path).map_err(CertError::KeyPathError)?;
let cert = KeyCertPair::new_selfsigned_certificate(config, &self.id)?;
// Creating files with permission 644 owned by the MQTT broker
let mut cert_file =
create_new_file(&self.cert_path, crate::BROKER_USER, crate::BROKER_GROUP)
.map_err(|err| err.cert_context(self.cert_path.clone()))?;
let mut key_file = create_new_file(&self.key_path, crate::BROKER_USER, crate::BROKER_GROUP)
.map_err(|err| err.key_context(self.key_path.clone()))?;
let cert_pem = cert.certificate_pem_string()?;
cert_file.write_all(cert_pem.as_bytes())?;
cert_file.sync_all()?;
// Prevent the certificate to be overwritten
set_permission(&cert_file, 0o444)?;
{
// Make sure the key is secret, before write
set_permission(&key_file, 0o600)?;
// Zero the private key on drop
let cert_key = cert.private_key_pem_string()?;
key_file.write_all(cert_key.as_bytes())?;
key_file.sync_all()?;
// Prevent the key to be overwritten
set_permission(&key_file, 0o400)?;
}
Ok(())
}
}
fn create_new_file(path: impl AsRef<Path>, user: &str, group: &str) -> Result<File, CertError> {
let file = OpenOptions::new()
.write(true)
.create_new(true)
.open(path.as_ref())?;
// Ignore errors - This was the behavior with the now deprecated user manager.
// - When `tedge cert create` is not run as root, a certificate is created but owned by the user running the command.
// - A better approach could be to remove this `chown` and run the command as mosquitto.
let _ = tedge_utils::file::change_user_and_group(path.as_ref(), user, group);
Ok(file)
}
#[cfg(test)]
mod tests {
use super::*;
use assert_matches::assert_matches;
use std::fs;
use tempfile::*;
#[test]
fn basic_usage() {
let dir = tempdir().unwrap();
let cert_path = temp_file_path(&dir, "my-device-cert.pem");
let key_path = temp_file_path(&dir, "my-device-key.pem");
let id = "my-device-id";
let cmd = CreateCertCmd {
id: String::from(id),
cert_path: cert_path.clone(),
key_path: key_path.clone(),
};
assert_matches!(
cmd.create_test_certificate(&NewCertificateConfig::default()),
Ok(())
);
assert_eq!(parse_pem_file(&cert_path).unwrap().tag, "CERTIFICATE");
assert_eq!(parse_pem_file(&key_path).unwrap().tag, "PRIVATE KEY");
}
#[test]
fn check_certificate_is_not_overwritten() {
let dir = tempdir().unwrap();
let cert_path = temp_file_path(&dir, "my-device-cert.pem");
let key_path = temp_file_path(&dir, "my-device-key.pem");
let cert_content = "some cert content";
let key_content = "some key content";
fs::write(&cert_path, cert_content).unwrap();
fs::write(&key_path, key_content).unwrap();
let cmd = CreateCertCmd {
id: "my-device-id".into(),
cert_path: cert_path.clone(),
key_path: key_path.clone(),
};
assert!(cmd
.create_test_certificate(&NewCertificateConfig::default())
.ok()
.is_none());
assert_eq!(fs::read(&cert_path).unwrap(), cert_content.as_bytes());
assert_eq!(fs::read(&key_path).unwrap(), key_content.as_bytes());
}
#[test]
fn create_certificate_in_non_existent_directory() {
let dir = tempdir().unwrap();
let key_path = temp_file_path(&dir, "my-device-key.pem");
let cert_path = FilePath::from("/non/existent/cert/path");
let cmd = CreateCertCmd {
id: "my-device-id".into(),
cert_path,
key_path,
};
let cert_error = cmd
.create_test_certificate(&NewCertificateConfig::default())
.unwrap_err();
assert_matches!(cert_error, CertError::CertPathError { .. });
}
#[test]
fn create_key_in_non_existent_directory() {
let dir = tempdir().unwrap();
let cert_path = temp_file_path(&dir, "my-device-cert.pem");
let key_path = FilePath::from("/non/existent/key/path");
let cmd = CreateCertCmd {
id: "my-device-id".into(),
cert_path,
key_path,
};
let cert_error = cmd
.create_test_certificate(&NewCertificateConfig::default())
.unwrap_err();
assert_matches!(cert_error, CertError::KeyPathError { .. });
}
fn temp_file_path(dir: &TempDir, filename: &str) -> FilePath {
dir.path().join(filename).into()
}
fn parse_pem_file(path: impl AsRef<Path>) -> Result<pem::Pem, String> {
let content = fs::read(path).map_err(|err| err.to_string())?;
pem::parse(content).map_err(|err| err.to_string())
}
}
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