Add ssh-agent native auth

src/native.rs

@@ -546,7 +546,7 @@ fn strip_quotes(raw: &str) -> &str {
         .unwrap_or(raw)
 }
 
-fn parse_ssh_ed25519_public_blob(blob: &[u8]) -> Result<[u8; 32]> {
+pub fn parse_ssh_ed25519_public_blob(blob: &[u8]) -> Result<[u8; 32]> {
     let mut cursor = blob;
     let key_type = read_ssh_string(&mut cursor)?;
     anyhow::ensure!(key_type == b"ssh-ed25519", "key blob type mismatch");
@@ -558,6 +558,13 @@ fn parse_ssh_ed25519_public_blob(blob: &[u8]) -> Result<[u8; 32]> {
     Ok(out)
 }
 
+pub fn ssh_ed25519_public_blob(public_key: &[u8; 32]) -> Vec<u8> {
+    let mut out = Vec::new();
+    write_ssh_string(&mut out, b"ssh-ed25519");
+    write_ssh_string(&mut out, public_key);
+    out
+}
+
 fn read_ssh_string<'a>(cursor: &mut &'a [u8]) -> Result<&'a [u8]> {
     anyhow::ensure!(cursor.len() >= 4, "truncated SSH string length");
     let len = u32::from_be_bytes(cursor[..4].try_into().unwrap()) as usize;
@@ -568,21 +575,18 @@ fn read_ssh_string<'a>(cursor: &mut &'a [u8]) -> Result<&'a [u8]> {
     Ok(value)
 }
 
-#[cfg(test)]
-fn ssh_ed25519_authorized_key_line(signing_key: &SigningKey) -> String {
-    let verifying = VerifyingKey::from(signing_key);
-    let mut blob = Vec::new();
-    write_ssh_string(&mut blob, b"ssh-ed25519");
-    write_ssh_string(&mut blob, &verifying.to_bytes());
-    format!("ssh-ed25519 {} test-key", STANDARD.encode(blob))
-}
-
-#[cfg(test)]
 fn write_ssh_string(out: &mut Vec<u8>, value: &[u8]) {
     out.extend_from_slice(&(value.len() as u32).to_be_bytes());
     out.extend_from_slice(value);
 }
 
+#[cfg(test)]
+fn ssh_ed25519_authorized_key_line(signing_key: &SigningKey) -> String {
+    let verifying = VerifyingKey::from(signing_key);
+    let blob = ssh_ed25519_public_blob(&verifying.to_bytes());
+    format!("ssh-ed25519 {} test-key", STANDARD.encode(blob))
+}
+
 pub fn known_host_line(host: &str, key: &HostPublicKey, source: &str, first_seen: u64) -> String {
     format!(
         "{} {} {} first-seen={} source={}",