add ssl_ca to accepted connection url query params

CHANGELOG.md

@@ -8,6 +8,8 @@ for Rust libraries in [RFC #1105](https://github.com/rust-lang/rfcs/blob/master/
 
 ### Added
 
+* `MysqlConnection::establish` is able to initiate SSL connection while specifying certificate roots. The database URL should contain `ssl_ca` parameter with a path pointing to the certificate roots. [See docs](https://dev.mysql.com/doc/refman/5.7/en/connection-options.html#option_general_ssl-ca) if desired.
+
 * `MysqlConnection::establish` is able to initiate SSL connection. The database URL should contain `ssl_mode` parameter with a value of the [MySQL client command option `--ssl-mode`](https://dev.mysql.com/doc/refman/5.7/en/connection-options.html#option_general_ssl-mode) if desired.
 
 * `Connection` and `SimpleConnection` traits are implemented for a broader range

diesel/src/mysql/connection/mod.rs

@@ -58,9 +58,10 @@ impl Connection for MysqlConnection {
 
     /// Establishes a new connection to the MySQL database
     /// `database_url` may be enhanced by GET parameters
-    /// `mysql://[user[:password]@]host/database_name[?unix_socket=socket-path&ssl_mode=SSL_MODE*]`
+    /// `mysql://[user[:password]@]host/database_name[?unix_socket=socket-path&ssl_mode=SSL_MODE*&ssl_ca=/etc/ssl/certs/ca-certificates.crt]`
     ///
-    /// * `unix_socket` excepts the path to the unix socket
+    /// * `unix_socket` expects the path to the unix socket
+    /// * `ssl_ca` accepts a path to the system's certificate roots
     /// * `ssl_mode` expects a value defined for MySQL client command option `--ssl-mode`
     /// See <https://dev.mysql.com/doc/refman/5.7/en/connection-options.html#option_general_ssl-mode>
     fn establish(database_url: &str) -> ConnectionResult<Self> {

diesel/src/mysql/connection/raw.rs

@@ -51,6 +51,9 @@ impl RawConnection {
         if let Some(ssl_mode) = connection_options.ssl_mode() {
             self.set_ssl_mode(ssl_mode)
         }
+        if let Some(ssl_ca) = connection_options.ssl_ca() {
+            self.set_ssl_ca(ssl_ca)
+        }
 
         unsafe {
             // Make sure you don't use the fake one!
@@ -197,6 +200,16 @@ impl RawConnection {
             )
         };
     }
+
+    fn set_ssl_ca(&self, ssl_ca: &CStr) {
+        unsafe {
+            mysqlclient_sys::mysql_options(
+                self.0.as_ptr(),
+                mysqlclient_sys::mysql_option::MYSQL_OPT_SSL_CA,
+                ssl_ca.as_ptr() as *const std::ffi::c_void,
+            )
+        };
+    }
 }
 
 impl Drop for RawConnection {

diesel/src/mysql/connection/url.rs

@@ -49,6 +49,7 @@ pub struct ConnectionOptions {
     unix_socket: Option<CString>,
     client_flags: CapabilityFlags,
     ssl_mode: Option<mysql_ssl_mode>,
+    ssl_ca: Option<CString>,
 }
 
 impl ConnectionOptions {
@@ -76,6 +77,11 @@ impl ConnectionOptions {
             _ => None,
         };
 
+        let ssl_ca = match query_pairs.get("ssl_ca") {
+            Some(v) => Some(CString::new(v.as_bytes())?),
+            _ => None,
+        };
+
         let ssl_mode = match query_pairs.get("ssl_mode") {
             Some(v) => {
                 let ssl_mode = match v.to_lowercase().as_str() {
@@ -123,6 +129,7 @@ impl ConnectionOptions {
             unix_socket: unix_socket,
             client_flags: client_flags,
             ssl_mode: ssl_mode,
+            ssl_ca: ssl_ca,
         })
     }
 
@@ -150,6 +157,10 @@ impl ConnectionOptions {
         self.unix_socket.as_deref()
     }
 
+    pub fn ssl_ca(&self) -> Option<&CStr> {
+        self.ssl_ca.as_deref()
+    }
+
     pub fn client_flags(&self) -> CapabilityFlags {
         self.client_flags
     }
@@ -293,6 +304,27 @@ fn unix_socket_tests() {
     );
 }
 
+#[test]
+fn ssl_ca_tests() {
+    let ssl_ca = "/etc/ssl/certs/ca-certificates.crt";
+    let username = "foo";
+    let password = "bar";
+    let db_url = format!(
+        "mysql://{}:{}@localhost?ssl_ca={}",
+        username, password, ssl_ca
+    );
+    let conn_opts = ConnectionOptions::parse(db_url.as_str()).unwrap();
+    let cstring = |s| CString::new(s).unwrap();
+    assert_eq!(None, conn_opts.host);
+    assert_eq!(None, conn_opts.port);
+    assert_eq!(cstring(username), conn_opts.user);
+    assert_eq!(cstring(password), conn_opts.password.unwrap());
+    assert_eq!(
+        CString::new(ssl_ca).unwrap(),
+        conn_opts.ssl_ca.unwrap()
+    );
+}
+
 #[test]
 fn ssl_mode() {
     let ssl_mode = |url| ConnectionOptions::parse(url).unwrap().ssl_mode();