feat(mysql): make rsa dependency optional (RUSTSEC-2023-0071)

.github/workflows/examples.yml

@@ -42,6 +42,7 @@ jobs:
     services:
       mysql:
         image: mysql:latest
+        command: --default-authentication-plugin=mysql_native_password
         env:
           MYSQL_ROOT_PASSWORD: password
         ports:

sqlx-mysql/Cargo.toml

@@ -14,6 +14,7 @@ json = ["sqlx-core/json", "serde"]
 any = ["sqlx-core/any"]
 offline = ["sqlx-core/offline", "serde/derive"]
 migrate = ["sqlx-core/migrate"]
+rsa = ["dep:rsa"]
 
 # Type Integration features
 bigdecimal = ["dep:bigdecimal", "sqlx-core/bigdecimal"]
@@ -38,7 +39,7 @@ hkdf = "0.12.0"
 hmac = { version = "0.12.0", default-features = false }
 md-5 = { version = "0.10.0", default-features = false }
 rand = { version = "0.8.4", default-features = false, features = ["std", "std_rng"] }
-rsa = "0.9"
+rsa = { version = "0.9", optional = true }
 sha1 = { version = "0.10.1", default-features = false }
 sha2 = { version = "0.10.0", default-features = false }
 

sqlx-mysql/src/connection/auth.rs

@@ -2,7 +2,9 @@ use bytes::buf::Chain;
 use bytes::Bytes;
 use digest::{Digest, OutputSizeUser};
 use generic_array::GenericArray;
+#[cfg(feature = "rsa")]
 use rand::thread_rng;
+#[cfg(feature = "rsa")]
 use rsa::{pkcs8::DecodePublicKey, Oaep, RsaPublicKey};
 use sha1::Sha1;
 use sha2::Sha256;
@@ -131,9 +133,9 @@ fn scramble_sha256(
 
 async fn encrypt_rsa<'s>(
     stream: &'s mut MySqlStream,
-    public_key_request_id: u8,
+    _public_key_request_id: u8,
     password: &'s str,
-    nonce: &'s Chain<Bytes, Bytes>,
+    _nonce: &'s Chain<Bytes, Bytes>,
 ) -> Result<Vec<u8>, Error> {
     // https://mariadb.com/kb/en/caching_sha2_password-authentication-plugin/
 
@@ -142,29 +144,41 @@ async fn encrypt_rsa<'s>(
         return Ok(to_asciz(password));
     }
 
-    // client sends a public key request
-    stream.write_packet(&[public_key_request_id][..])?;
-    stream.flush().await?;
-
-    // server sends a public key response
-    let packet = stream.recv_packet().await?;
-    let rsa_pub_key = &packet[1..];
-
-    // xor the password with the given nonce
-    let mut pass = to_asciz(password);
-
-    let (a, b) = (nonce.first_ref(), nonce.last_ref());
-    let mut nonce = Vec::with_capacity(a.len() + b.len());
-    nonce.extend_from_slice(a);
-    nonce.extend_from_slice(b);
-
-    xor_eq(&mut pass, &nonce);
-
-    // client sends an RSA encrypted password
-    let pkey = parse_rsa_pub_key(rsa_pub_key)?;
-    let padding = Oaep::new::<sha1::Sha1>();
-    pkey.encrypt(&mut thread_rng(), padding, &pass[..])
-        .map_err(Error::protocol)
+    // Non-TLS RSA password encryption requires the `rsa` feature.
+    // It is opt-in because RUSTSEC-2023-0071 (Marvin Attack timing side-channel)
+    // has no patched release; disable it when all connections use TLS.
+    #[cfg(not(feature = "rsa"))]
+    return Err(err_protocol!(
+        "sha256_password / caching_sha2_password over non-TLS requires the `rsa` feature \
+         (disabled by default due to RUSTSEC-2023-0071)"
+    ));
+
+    #[cfg(feature = "rsa")]
+    {
+        // client sends a public key request
+        stream.write_packet(&[_public_key_request_id][..])?;
+        stream.flush().await?;
+
+        // server sends a public key response
+        let packet = stream.recv_packet().await?;
+        let rsa_pub_key = &packet[1..];
+
+        // xor the password with the given nonce
+        let mut pass = to_asciz(password);
+
+        let (a, b) = (_nonce.first_ref(), _nonce.last_ref());
+        let mut nonce = Vec::with_capacity(a.len() + b.len());
+        nonce.extend_from_slice(a);
+        nonce.extend_from_slice(b);
+
+        xor_eq(&mut pass, &nonce);
+
+        // client sends an RSA encrypted password
+        let pkey = parse_rsa_pub_key(rsa_pub_key)?;
+        let padding = Oaep::new::<sha1::Sha1>();
+        pkey.encrypt(&mut thread_rng(), padding, &pass[..])
+            .map_err(Error::protocol)
+    }
 }
 
 // XOR(x, y)
@@ -186,6 +200,7 @@ fn to_asciz(s: &str) -> Vec<u8> {
 }
 
 // https://docs.rs/rsa/0.3.0/rsa/struct.RSAPublicKey.html?search=#example-1
+#[cfg(feature = "rsa")]
 fn parse_rsa_pub_key(key: &[u8]) -> Result<RsaPublicKey, Error> {
     let pem = std::str::from_utf8(key).map_err(Error::protocol)?;
 

tests/docker-compose.yml

@@ -16,6 +16,7 @@ services:
             MYSQL_ROOT_HOST: '%'
             MYSQL_ROOT_PASSWORD: password
             MYSQL_DATABASE: sqlx
+        command: --default-authentication-plugin=mysql_native_password
 
     mysql_8_client_ssl:
         build: