From 653c5d682fb23a57cb39255da0164636ddefb7ab Mon Sep 17 00:00:00 2001
From: Tom Smeding <tom.smeding@gmail.com>
Date: Thu, 17 Sep 2020 23:57:46 +0200
Subject: rust: Proper authentication data generation

---
 rust/Cargo.toml    |  3 ++
 rust/src/auth.rs   | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 rust/src/bel.rs    |  6 ++++
 rust/src/editor.rs |  5 ++--
 rust/src/main.rs   |  8 ++++--
 5 files changed, 101 insertions(+), 5 deletions(-)
 create mode 100644 rust/src/auth.rs
 create mode 100644 rust/src/bel.rs

diff --git a/rust/Cargo.toml b/rust/Cargo.toml
index 2c95d3c..869baeb 100644
--- a/rust/Cargo.toml
+++ b/rust/Cargo.toml
@@ -11,3 +11,6 @@ tokio = { version = "0.2", features = ["rt-threaded"] }
 futures = "0.3"
 once_cell = "1.4"
 unicode-width = "^0.1.8"
+users = "0.10"
+dirs = "3.0"
+rand = "0.7"
diff --git a/rust/src/auth.rs b/rust/src/auth.rs
new file mode 100644
index 0000000..51b4820
--- /dev/null
+++ b/rust/src/auth.rs
@@ -0,0 +1,84 @@
+// use users::get_current_username;
+// use dirs::data_dir;
+use std::borrow::Borrow;
+use std::ops::Deref;
+use std::{fs, io};
+use std::path::{Path, PathBuf};
+use rand::{Rng, CryptoRng};
+use crate::error::{IntoIOError, IntoIOResult};
+
+pub struct User(String);
+pub struct Pass(String);
+
+impl Borrow<str> for User { fn borrow(&self) -> &str { &self.0 } }
+impl Borrow<str> for Pass { fn borrow(&self) -> &str { &self.0 } }
+
+impl Deref for User { type Target = str; fn deref(&self) -> &Self::Target { &self.0 } }
+impl Deref for Pass { type Target = str; fn deref(&self) -> &Self::Target { &self.0 } }
+
+static PASSWORD_FILE_SUBDIR: &str = "tomsg_client";  // ~/.local/share/PASSWORD_FILE_SUBDIR/...
+static PASSWORD_FILE_SUBDIR_HOME: &str = ".tomsg_client";  // ~/PASSWORD_FILE_SUBDIR_HOME/...
+static PASSWORD_FILE_NAME: &str = "password.txt";
+
+pub fn get_auth_info() -> io::Result<(User, Pass)> {
+    Ok((get_username()?, obtain_password()?))
+}
+
+fn get_username() -> io::Result<User> {
+    match users::get_current_username().map(|u| u.to_str().map(|u| u.to_string())) {
+        Some(Some(u)) => Ok(User(u)),
+        Some(None) => Err("Username not valid UTF-8".ioerr()),
+        None => Err("Cannot obtain username".ioerr()),
+    }
+}
+
+fn obtain_password() -> io::Result<Pass> {
+    let dir = storage_directory()?;
+    if let Ok(pass) = read_password(&dir) {
+        return Ok(pass);
+    }
+
+    let pass = generate_password();
+    write_password(&dir, &pass)
+        .map_err(|e| format!("Cannot write password to home directory: {}", e).ioerr())?;
+    Ok(pass)
+}
+
+fn read_password(data_dir: &Path) -> io::Result<Pass> {
+    fs::read(data_dir.join(PASSWORD_FILE_NAME))
+        .and_then(|mut v| {
+            // Trim final newline if there is one
+            if v.last() == Some(&b'\n') {
+                v.pop();
+            }
+            String::from_utf8(v).map(Pass).iores()
+        })
+}
+
+fn write_password(data_dir: &Path, pass: &Pass) -> io::Result<()> {
+    fs::create_dir_all(data_dir)?;
+    fs::write(data_dir.join(PASSWORD_FILE_NAME), pass.as_bytes())
+}
+
+fn storage_directory() -> io::Result<PathBuf> {
+    dirs::data_dir()
+        .map(|mut dir| { dir.push(PASSWORD_FILE_SUBDIR); dir })
+        .or_else(|| dirs::home_dir()
+                        .map(|mut dir| {
+                            dir.push(PASSWORD_FILE_SUBDIR_HOME); dir
+                        }))
+        .ok_or("Cannot determine home directory".ioerr())
+}
+
+fn generate_password() -> Pass {
+    Pass(secure_rng()
+            .sample_iter(rand::distributions::Alphanumeric)
+            .take(32)
+            .collect::<String>()
+    )
+}
+
+// Wrapper for thread_rng() that statically enforces that the generator is CryptoRng.
+fn secure_rng() -> impl Rng + CryptoRng {
+    rand::thread_rng()
+}
diff --git a/rust/src/bel.rs b/rust/src/bel.rs
new file mode 100644
index 0000000..fec5a3c
--- /dev/null
+++ b/rust/src/bel.rs
@@ -0,0 +1,6 @@
+use std::io::Write;
+
+pub fn bel() {
+    print!("\x07");
+    std::io::stdout().flush().unwrap();
+}
diff --git a/rust/src/editor.rs b/rust/src/editor.rs
index 7d83904..6284570 100644
--- a/rust/src/editor.rs
+++ b/rust/src/editor.rs
@@ -1,5 +1,5 @@
-use std::io::Write;
 use termion::event::Key;
+use crate::bel;
 
 #[derive(Debug, Default)]
 pub struct Editor {
@@ -56,8 +56,7 @@ impl Editor {
             }
 
             _ => {
-                print!("\x07");
-                std::io::stdout().flush().unwrap();
+                bel::bel();
             }
         };
 
diff --git a/rust/src/main.rs b/rust/src/main.rs
index 6e10938..5a50f3b 100644
--- a/rust/src/main.rs
+++ b/rust/src/main.rs
@@ -18,6 +18,8 @@ use unicode_width::UnicodeWidthChar;
 use crate::editor::Editor;
 use crate::error::IntoIOError;
 
+mod auth;
+mod bel;
 mod editor;
 mod error;
 
@@ -537,8 +539,10 @@ async fn async_main() -> io::Result<()> {
     let addr = ("127.0.0.1", 29538);
     let (conn, pushchan) = Connection::connect(connection::Type::Plain, addr).await?;
 
-    let user = Word::try_from(String::from("tom")).unwrap();
-    let pass = Line::try_from(String::from("kaas")).unwrap();
+    let (user, pass) = auth::get_auth_info()?;
+
+    let user = Word::try_from(user.to_string()).unwrap();
+    let pass = Line::try_from(pass.to_string()).unwrap();
 
     send_command(&conn, Command::Register { username: user.clone(), password: pass.clone() }).await?;
 
-- 
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