From ac9098aba6568028c267837b737dc990318f0d94 Mon Sep 17 00:00:00 2001
From: Jovi Hsu <jv.hsu@outlook.com>
Date: Tue, 14 Nov 2023 15:45:28 +0000
Subject: [PATCH] Fix: do not panic when connect to non-ssh server; send our
 version string first after connection setup

---
 src/config/version.rs | 2 +-
 src/session/mod.rs    | 5 +++--
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/config/version.rs b/src/config/version.rs
index 32ca679..dd253d0 100644
--- a/src/config/version.rs
+++ b/src/config/version.rs
@@ -58,7 +58,7 @@ impl SshVersion {
         S: Read,
     {
         let buf = read_version(stream, timeout)?;
-        if &buf[0..4] != SSH_MAGIC {
+        if buf.len() < 4 || &buf[0..4] != SSH_MAGIC {
             error!("SSH version magic doesn't match");
             error!("Probably not an ssh server");
         }
diff --git a/src/session/mod.rs b/src/session/mod.rs
index 29a0e55..28a2341 100644
--- a/src/session/mod.rs
+++ b/src/session/mod.rs
@@ -50,14 +50,15 @@ where
             .connect(),
             SessionState::Version(mut config, mut stream) => {
                 info!("start for version negotiation.");
+                // Send Client version
+                config.ver.send_our_version(&mut stream)?;
+
                 // Receive the server version
                 config
                     .ver
                     .read_server_version(&mut stream, config.timeout)?;
                 // Version validate
                 config.ver.validate()?;
-                // Send Client version
-                config.ver.send_our_version(&mut stream)?;
 
                 // from now on
                 // each step of the interaction is subject to the ssh constraints on the packet