Prevent passwords from being logged

As passwords were treated as Strings, and Debug was derived, any debug
logging would print the full password in the diagnostic logs of the
applicaiton running this library.

By wrapping the password in Secret and implementing most traits, we can
(almost) seamlessly prevent passwords from being displayed in those
contexts.

sqlx-core/src/connection.rs

@@ -183,6 +183,44 @@ impl LogSettings {
     }
 }
 
+/// `Secret` is a wrapper around a String which ensures it is not going
+/// to be masked when printed in a regular fashion
+#[derive(Clone,PartialEq,Eq)]
+pub struct Secret(String);
+
+impl std::fmt::Debug for Secret {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str("********")
+    }
+}
+impl std::fmt::Display for Secret {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        std::fmt::Debug::fmt(self, f)
+    }
+}
+impl From<String> for Secret {
+    fn from(value: String) -> Self {
+        Self(value)
+    }
+}
+impl From<&str> for Secret {
+    fn from(value: &str) -> Self {
+        Self(value.to_owned())
+    }
+}
+impl From<Secret> for String {
+    fn from(value: Secret) -> Self {
+        value.0
+    }
+}
+impl std::ops::Deref for Secret {
+    type Target = str;
+
+    fn deref(&self) -> &Self::Target {
+        self.0.deref()
+    }
+}
+
 pub trait ConnectOptions: 'static + Send + Sync + FromStr<Err = Error> + Debug + Clone {
     type Connection: Connection + ?Sized;
 

sqlx-mysql/src/options/mod.rs

@@ -5,6 +5,7 @@ mod parse;
 mod ssl_mode;
 
 use crate::{connection::LogSettings, net::tls::CertificateInput};
+use sqlx_core::connection::Secret;
 pub use ssl_mode::MySqlSslMode;
 
 /// Options and flags which can be used to configure a MySQL connection.
@@ -57,7 +58,7 @@ pub struct MySqlConnectOptions {
     pub(crate) port: u16,
     pub(crate) socket: Option<PathBuf>,
     pub(crate) username: String,
-    pub(crate) password: Option<String>,
+    pub(crate) password: Option<Secret>,
     pub(crate) database: Option<String>,
     pub(crate) ssl_mode: MySqlSslMode,
     pub(crate) ssl_ca: Option<CertificateInput>,
@@ -132,7 +133,7 @@ impl MySqlConnectOptions {
 
     /// Sets the password to connect with.
     pub fn password(mut self, password: &str) -> Self {
-        self.password = Some(password.to_owned());
+        self.password = Some(password.into());
         self
     }
 

sqlx-postgres/src/options/mod.rs

@@ -3,6 +3,7 @@ use std::env::var;
 use std::fmt::{Display, Write};
 use std::path::{Path, PathBuf};
 
+use sqlx_core::connection::Secret;
 pub use ssl_mode::PgSslMode;
 
 use crate::{connection::LogSettings, net::tls::CertificateInput};
@@ -83,7 +84,7 @@ pub struct PgConnectOptions {
     pub(crate) port: u16,
     pub(crate) socket: Option<PathBuf>,
     pub(crate) username: String,
-    pub(crate) password: Option<String>,
+    pub(crate) password: Option<Secret>,
     pub(crate) database: Option<String>,
     pub(crate) ssl_mode: PgSslMode,
     pub(crate) ssl_root_cert: Option<CertificateInput>,

sqlx-postgres/src/options/parse.rs

@@ -204,6 +204,8 @@ fn it_parses_password_with_non_ascii_chars_correctly() {
     let opts = PgConnectOptions::from_str(url).unwrap();
 
     assert_eq!(Some("p@ssw0rd".into()), opts.password);
+    assert_eq!("********", format!("{0}", opts.password.unwrap()));
+    assert_eq!("********", format!("{0:?}", opts.password.unwrap()));
 }
 
 #[test]