Function get_quote_via_configfs

tdx-attest/src/linux.rs:290–333

Get quote using Linux ConfigFS TSM interface (Linux 6.7+)

(report_data: &TdxReportData)

/// Get quote using Linux ConfigFS TSM interface (Linux 6.7+)
fn get_quote_via_configfs(report_data: &TdxReportData) -> Result<Vec<u8>> {
    let configfs_path = prepare_configfs()?;

    let inblob_path = format!("{}/inblob", configfs_path);
    let outblob_path = format!("{}/outblob", configfs_path);
    let generation_path = format!("{}/generation", configfs_path);

    let lock_file = OpenOptions::new()
        .write(true)
        .open(&inblob_path)
        .map_err(|e| TdxAttestError::Unexpected(format!("open {inblob_path}: {e}")))?;

    let ret = unsafe { libc::flock(lock_file.as_raw_fd(), libc::LOCK_EX) };
    if ret != 0 {
        let err = std::io::Error::last_os_error();
        return Err(TdxAttestError::Unexpected(format!(
            "flock {inblob_path}: {err}"
        )));
    }

    let gen1 = read_generation(&generation_path)?;
    write_inblob_with_retry(&inblob_path, report_data)?;

    let gen2 = wait_for_generation_change(&generation_path, gen1)?;
    if gen2 != gen1 + 1 {
        return Err(TdxAttestError::Busy);
    }

    let quote = read_outblob_with_retry(&outblob_path)?;

    let gen3 = read_generation(&generation_path)?;
    if gen3 != gen2 {
        return Err(TdxAttestError::Busy);
    }

    if quote.len() <= QUOTE_MIN_SIZE || quote.len() >= QUOTE_BUF_SIZE {
        return Err(TdxAttestError::QuoteFailure(format!(
            "invalid quote size: {}",
            quote.len()
        )));
    }

    Ok(quote)
}

fn prepare_configfs() -> Result<String> {
    if let Ok(path) = std::env::var(CONFIGFS_PATH_ENV) {