v0.4.0: add first-time TLS setup and server help

1 files changed, 140 insertions, 0 deletions

diff --git a/src/server/setup.rs b/src/server/setup.rs
new file mode 100644
index 0000000..96982c5
--- /dev/null
+++ b/src/server/setup.rs
@@ -0,0 +1,140 @@
+//! First-time TLS identity generation for the server.
+
+use std::path::{Path, PathBuf};
+use std::process::Command;
+
+#[derive(Debug)]
+pub struct SetupReport {
+    pub identity: PathBuf,
+    pub key: PathBuf,
+    pub cert: PathBuf,
+}
+
+/// Generate a self-signed RSA identity in `dir`.
+///
+/// Produces `identity.p12` (empty password, matching `native_tls`), `key.pem`,
+/// and `cert.pem`. Refuses to overwrite an existing identity.
+pub fn init_identity(dir: &Path, common_name: &str) -> Result<SetupReport, String> {
+    let common_name = if common_name.trim().is_empty() {
+        "localhost"
+    } else {
+        common_name.trim()
+    };
+
+    let identity = dir.join("identity.p12");
+    let key = dir.join("key.pem");
+    let cert = dir.join("cert.pem");
+
+    let existing: Vec<String> = [&identity, &key, &cert]
+        .into_iter()
+        .filter(|path| path.exists())
+        .map(|path| path.display().to_string())
+        .collect();
+    if !existing.is_empty() {
+        return Err(format!(
+            "Refusing to overwrite existing TLS files: {}\n\
+             Remove them first if you really want a new identity.",
+            existing.join(", ")
+        ));
+    }
+
+    std::fs::create_dir_all(dir)
+        .map_err(|error| format!("Could not create {}: {error}", dir.display()))?;
+
+    let manual = manual_instructions(common_name);
+    let subject = format!("/CN={common_name}");
+
+    run_openssl(
+        dir,
+        &[
+            "req",
+            "-x509",
+            "-newkey",
+            "rsa:2048",
+            "-keyout",
+            "key.pem",
+            "-out",
+            "cert.pem",
+            "-days",
+            "3650",
+            "-nodes",
+            "-subj",
+            &subject,
+        ],
+        "generate the certificate",
+        &manual,
+    )?;
+
+    run_openssl(
+        dir,
+        &[
+            "pkcs12",
+            "-export",
+            "-out",
+            "identity.p12",
+            "-inkey",
+            "key.pem",
+            "-in",
+            "cert.pem",
+            "-passout",
+            "pass:",
+            "-keypbe",
+            "PBE-SHA1-3DES",
+            "-certpbe",
+            "PBE-SHA1-3DES",
+            "-macalg",
+            "sha1",
+        ],
+        "build identity.p12",
+        &manual,
+    )?;
+
+    #[cfg(unix)]
+    {
+        use std::os::unix::fs::PermissionsExt;
+
+        for path in [&key, &identity] {
+            let metadata = std::fs::metadata(path)
+                .map_err(|error| format!("Could not inspect {}: {error}", path.display()))?;
+            let mut permissions = metadata.permissions();
+            permissions.set_mode(0o600);
+            std::fs::set_permissions(path, permissions).map_err(|error| {
+                format!("Could not protect {}: {error}", path.display())
+            })?;
+        }
+    }
+
+    Ok(SetupReport {
+        identity,
+        key,
+        cert,
+    })
+}
+
+fn run_openssl(dir: &Path, args: &[&str], action: &str, manual: &str) -> Result<(), String> {
+    let output = Command::new("openssl")
+        .current_dir(dir)
+        .args(args)
+        .output()
+        .map_err(|error| format!("Could not run openssl to {action}: {error}\n\n{manual}"))?;
+
+    if output.status.success() {
+        return Ok(());
+    }
+
+    let stderr = String::from_utf8_lossy(&output.stderr);
+    Err(format!(
+        "openssl failed to {action}:\n{}\n\n{manual}",
+        stderr.trim()
+    ))
+}
+
+fn manual_instructions(common_name: &str) -> String {
+    format!(
+        "Install openssl, or run these commands manually:\n\
+         \x20 openssl req -x509 -newkey rsa:2048 -keyout key.pem -out cert.pem \\\n\
+         \x20   -days 3650 -nodes -subj \"/CN={common_name}\"\n\
+         \x20 openssl pkcs12 -export -out identity.p12 -inkey key.pem -in cert.pem \\\n\
+         \x20   -passout pass:"
+    )
+}