chore(proxy): remove postgres config parser and md5 support (#9990)

Keeping the `mock` postgres cplane adaptor using "stock" tokio-postgres
allows us to remove a lot of dead weight from our actual postgres
connection logic.

libs/proxy/postgres-protocol2/Cargo.toml

@@ -10,7 +10,6 @@ byteorder.workspace = true
 bytes.workspace = true
 fallible-iterator.workspace = true
 hmac.workspace = true
-md-5 = "0.10"
 memchr = "2.0"
 rand.workspace = true
 sha2.workspace = true

libs/proxy/postgres-protocol2/src/authentication/mod.rs

@@ -1,37 +1,2 @@
 //! Authentication protocol support.
-use md5::{Digest, Md5};
-
 pub mod sasl;
-
-/// Hashes authentication information in a way suitable for use in response
-/// to an `AuthenticationMd5Password` message.
-///
-/// The resulting string should be sent back to the database in a
-/// `PasswordMessage` message.
-#[inline]
-pub fn md5_hash(username: &[u8], password: &[u8], salt: [u8; 4]) -> String {
-    let mut md5 = Md5::new();
-    md5.update(password);
-    md5.update(username);
-    let output = md5.finalize_reset();
-    md5.update(format!("{:x}", output));
-    md5.update(salt);
-    format!("md5{:x}", md5.finalize())
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-
-    #[test]
-    fn md5() {
-        let username = b"md5_user";
-        let password = b"password";
-        let salt = [0x2a, 0x3d, 0x8f, 0xe0];
-
-        assert_eq!(
-            md5_hash(username, password, salt),
-            "md562af4dd09bbb41884907a838a3233294"
-        );
-    }
-}

libs/proxy/postgres-protocol2/src/message/backend.rs

@@ -79,7 +79,7 @@ pub enum Message {
     AuthenticationCleartextPassword,
     AuthenticationGss,
     AuthenticationKerberosV5,
-    AuthenticationMd5Password(AuthenticationMd5PasswordBody),
+    AuthenticationMd5Password,
     AuthenticationOk,
     AuthenticationScmCredential,
     AuthenticationSspi,
@@ -191,11 +191,7 @@ impl Message {
                 0 => Message::AuthenticationOk,
                 2 => Message::AuthenticationKerberosV5,
                 3 => Message::AuthenticationCleartextPassword,
-                5 => {
-                    let mut salt = [0; 4];
-                    buf.read_exact(&mut salt)?;
-                    Message::AuthenticationMd5Password(AuthenticationMd5PasswordBody { salt })
-                }
+                5 => Message::AuthenticationMd5Password,
                 6 => Message::AuthenticationScmCredential,
                 7 => Message::AuthenticationGss,
                 8 => Message::AuthenticationGssContinue,

libs/proxy/postgres-protocol2/src/password/mod.rs

@@ -8,7 +8,6 @@
 
 use crate::authentication::sasl;
 use hmac::{Hmac, Mac};
-use md5::Md5;
 use rand::RngCore;
 use sha2::digest::FixedOutput;
 use sha2::{Digest, Sha256};
@@ -88,20 +87,3 @@ pub(crate) async fn scram_sha_256_salt(
         base64::encode(server_key)
     )
 }
-
-/// **Not recommended, as MD5 is not considered to be secure.**
-///
-/// Hash password using MD5 with the username as the salt.
-///
-/// The client may assume the returned string doesn't contain any
-/// special characters that would require escaping.
-pub fn md5(password: &[u8], username: &str) -> String {
-    // salt password with username
-    let mut salted_password = Vec::from(password);
-    salted_password.extend_from_slice(username.as_bytes());
-
-    let mut hash = Md5::new();
-    hash.update(&salted_password);
-    let digest = hash.finalize();
-    format!("md5{:x}", digest)
-}

libs/proxy/postgres-protocol2/src/password/test.rs

@@ -9,11 +9,3 @@ async fn test_encrypt_scram_sha_256() {
         "SCRAM-SHA-256$4096:AQIDBAUGBwgJCgsMDQ4PEA==$8rrDg00OqaiWXJ7p+sCgHEIaBSHY89ZJl3mfIsf32oY=:05L1f+yZbiN8O0AnO40Og85NNRhvzTS57naKRWCcsIA="
     );
 }
-
-#[test]
-fn test_encrypt_md5() {
-    assert_eq!(
-        password::md5(b"secret", "foo"),
-        "md54ab2c5d00339c4b2a4e921d2dc4edec7"
-    );
-}