feat: add optional CryptoProvider to the client Config

It adds a new field to the client `Config, expecting the
`CryptoProvider` from the user.

It uses aws-lc-rs or ring providers by default if any of these features
are enabled.

It's based on the suggestion comment at bitcoindevkit#135, reference: bitcoindevkit#135 (comment)

src/client.rs

@@ -116,10 +116,14 @@ impl ClientType {
                     config.validate_domain(),
                     socks5,
                     config.timeout(),
+                    config.crypto_provider(),
+                )?,
+                None => RawClient::new_ssl(
+                    url.as_str(),
+                    config.validate_domain(),
+                    config.timeout(),
+                    config.crypto_provider(),
                 )?,
-                None => {
-                    RawClient::new_ssl(url.as_str(), config.validate_domain(), config.timeout())?
-                }
             };
 
             Ok(ClientType::SSL(client))

src/config.rs

@@ -1,5 +1,7 @@
 use std::time::Duration;
 
+use rustls::crypto::CryptoProvider;
+
 /// Configuration for an electrum client
 ///
 /// Refer to [`Client::from_config`] and [`ClientType::from_config`].
@@ -12,6 +14,9 @@ pub struct Config {
     socks5: Option<Socks5Config>,
     /// timeout in seconds, default None (depends on TcpStream default)
     timeout: Option<Duration>,
+    #[cfg(any(feature = "use-rustls", feature = "use-rustls-ring"))]
+    /// An optional [`CryptoProvider`] for users that don't want either default `aws-lc-rs` or `ring` providers
+    crypto_provider: Option<CryptoProvider>,
     /// number of retry if any error, default 1
     retry: u8,
     /// when ssl, validate the domain, default true
@@ -60,6 +65,13 @@ impl ConfigBuilder {
         self
     }
 
+    #[cfg(any(feature = "use-rustls", feature = "use-rustls-ring"))]
+    /// Sets the custom [`CryptoProvider`].
+    pub fn crypto_provider(mut self, crypto_provider: Option<CryptoProvider>) -> Self {
+        self.config.crypto_provider = crypto_provider;
+        self
+    }
+
     /// Sets the retry attempts number
     pub fn retry(mut self, retry: u8) -> Self {
         self.config.retry = retry;
@@ -135,6 +147,14 @@ impl Config {
     pub fn builder() -> ConfigBuilder {
         ConfigBuilder::new()
     }
+
+    #[cfg(any(feature = "use-rustls", feature = "use-rustls-ring"))]
+    /// Get the configuration for `crypto_provider`
+    ///
+    /// Set this with [`ConfigBuilder::crypto_provider`]
+    pub fn crypto_provider(&self) -> Option<&CryptoProvider> {
+        self.crypto_provider.as_ref()
+    }
 }
 
 impl Default for Config {
@@ -144,6 +164,7 @@ impl Default for Config {
             timeout: None,
             retry: 1,
             validate_domain: true,
+            crypto_provider: None,
         }
     }
 }

src/raw_client.rs

@@ -22,6 +22,10 @@ use bitcoin::{Script, Txid};
 #[cfg(feature = "use-openssl")]
 use openssl::ssl::{SslConnector, SslMethod, SslStream, SslVerifyMode};
 
+#[cfg(feature = "use-rustls")]
+use rustls::crypto::aws_lc_rs::default_provider;
+#[cfg(feature = "use-rustls-ring")]
+use rustls::crypto::ring::default_provider;
 #[cfg(all(
     any(
         feature = "default",
@@ -31,6 +35,7 @@ use openssl::ssl::{SslConnector, SslMethod, SslStream, SslVerifyMode};
     not(feature = "use-openssl")
 ))]
 use rustls::{
+    crypto::CryptoProvider,
     pki_types::ServerName,
     pki_types::{Der, TrustAnchor},
     ClientConfig, ClientConnection, RootCertStore, StreamOwned,
@@ -368,6 +373,7 @@ impl RawClient<ElectrumSslStream> {
         socket_addrs: A,
         validate_domain: bool,
         timeout: Option<Duration>,
+        crypto_provider: Option<&CryptoProvider>,
     ) -> Result<Self, Error> {
         debug!(
             "new_ssl socket_addrs.domain():{:?} validate_domain:{} timeout:{:?}",
@@ -378,16 +384,27 @@ impl RawClient<ElectrumSslStream> {
         if validate_domain {
             socket_addrs.domain().ok_or(Error::MissingDomain)?;
         }
+
+        let crypto_provider = match crypto_provider {
+            Some(provider) => provider.to_owned(),
+
+            #[cfg(feature = "use-rustls")]
+            None => default_provider(),
+
+            #[cfg(feature = "use-rustls-ring")]
+            None => default_provider(),
+        };
+
         match timeout {
             Some(timeout) => {
                 let stream = connect_with_total_timeout(socket_addrs.clone(), timeout)?;
                 stream.set_read_timeout(Some(timeout))?;
                 stream.set_write_timeout(Some(timeout))?;
-                Self::new_ssl_from_stream(socket_addrs, validate_domain, stream)
+                Self::new_ssl_from_stream(socket_addrs, validate_domain, stream, crypto_provider)
             }
             None => {
                 let stream = TcpStream::connect(socket_addrs.clone())?;
-                Self::new_ssl_from_stream(socket_addrs, validate_domain, stream)
+                Self::new_ssl_from_stream(socket_addrs, validate_domain, stream, crypto_provider)
             }
         }
     }
@@ -397,10 +414,13 @@ impl RawClient<ElectrumSslStream> {
         socket_addr: A,
         validate_domain: bool,
         tcp_stream: TcpStream,
+        crypto_provider: CryptoProvider,
     ) -> Result<Self, Error> {
         use std::convert::TryFrom;
 
-        let builder = ClientConfig::builder();
+        let builder = ClientConfig::builder_with_provider(crypto_provider.into())
+            .with_safe_default_protocol_versions()
+            .map_err(|e| Error::CouldNotBuildWithSafeDefaultVersion(e))?;
 
         let config = if validate_domain {
             socket_addr.domain().ok_or(Error::MissingDomain)?;
@@ -480,6 +500,7 @@ impl RawClient<ElectrumProxyStream> {
         validate_domain: bool,
         proxy: &crate::Socks5Config,
         timeout: Option<Duration>,
+        crypto_provider: Option<&CryptoProvider>,
     ) -> Result<RawClient<ElectrumSslStream>, Error> {
         let target = target_addr.to_target_addr()?;
 
@@ -496,7 +517,22 @@ impl RawClient<ElectrumProxyStream> {
         stream.get_mut().set_read_timeout(timeout)?;
         stream.get_mut().set_write_timeout(timeout)?;
 
-        RawClient::new_ssl_from_stream(target, validate_domain, stream.into_inner())
+        let crypto_provider = match crypto_provider {
+            Some(provider) => provider.to_owned(),
+
+            #[cfg(feature = "use-rustls")]
+            None => default_provider(),
+
+            #[cfg(feature = "use-rustls-ring")]
+            None => default_provider(),
+        };
+
+        RawClient::new_ssl_from_stream(
+            target,
+            validate_domain,
+            stream.into_inner(),
+            crypto_provider,
+        )
     }
 }
 

src/types.rs

@@ -318,6 +318,9 @@ pub enum Error {
     #[cfg(any(feature = "use-rustls", feature = "use-rustls-ring"))]
     /// Could not create a rustls client connection
     CouldNotCreateConnection(rustls::Error),
+    #[cfg(any(feature = "use-rustls", feature = "use-rustls-ring"))]
+    /// Could not create the `ClientConfig` with safe default protocol version
+    CouldNotBuildWithSafeDefaultVersion(rustls::Error),
 
     #[cfg(feature = "use-openssl")]
     /// Invalid OpenSSL method used
@@ -365,6 +368,7 @@ impl Display for Error {
             Error::MissingDomain => f.write_str("Missing domain while it was explicitly asked to validate it"),
             Error::CouldntLockReader => f.write_str("Couldn't take a lock on the reader mutex. This means that there's already another reader thread is running"),
             Error::Mpsc => f.write_str("Broken IPC communication channel: the other thread probably has exited"),
+            Error::CouldNotBuildWithSafeDefaultVersion(_) => f.write_str("Couldn't build the `ClientConfig` with safe default version"),
         }
     }
 }