From 7f5b5e5b5b6fe422814d232829d4e137f694962a Mon Sep 17 00:00:00 2001
From: Hylke Bons <hi@planetpeanut.uk>
Date: Thu, 9 Jun 2016 18:56:07 -0700
Subject: [PATCH] ssh fetcher: No longer allow deprecated and insecure DSA
 algorithm

---
 Sparkles/Command.cs    |  4 ++--
 Sparkles/SSHFetcher.cs | 25 +++++++++----------------
 2 files changed, 11 insertions(+), 18 deletions(-)

diff --git a/Sparkles/Command.cs b/Sparkles/Command.cs
index d1478d6a..cade6837 100644
--- a/Sparkles/Command.cs
+++ b/Sparkles/Command.cs
@@ -39,10 +39,10 @@ namespace Sparkles {
             StartInfo.FileName = path;
             StartInfo.Arguments = args;
 
-			StartInfo.CreateNoWindow = true;
+            StartInfo.CreateNoWindow = true;
             StartInfo.RedirectStandardOutput = true;
             StartInfo.RedirectStandardError = true;
-			StartInfo.UseShellExecute = false;
+            StartInfo.UseShellExecute = false;
 
             EnableRaisingEvents = true;
         }
diff --git a/Sparkles/SSHFetcher.cs b/Sparkles/SSHFetcher.cs
index 541c1e75..3d5707c7 100644
--- a/Sparkles/SSHFetcher.cs
+++ b/Sparkles/SSHFetcher.cs
@@ -89,27 +89,20 @@ namespace Sparkles {
 
         string FetchHostKey ()
         {
-            Logger.LogInfo ("Auth", "Fetching host key for " + RemoteUrl.Host);
-            string [] key_types = {"rsa", "dsa", "ecdsa"};
-            
-            foreach (string key_type in key_types) {
-                string args = "-t " + key_type + " " + "-p" + " ";
+            Logger.LogInfo ("Auth", string.Format ("Fetching host key for {0}", RemoteUrl.Host));
+            var ssh_keyscan = new Command ("ssh-keyscan", string.Format ("-t rsa -p 22 {0}", RemoteUrl.Host));
 
-                if (RemoteUrl.Port < 1)
-                    args += "22 " + RemoteUrl.Host;
-                else
-                    args += RemoteUrl.Port + " " + RemoteUrl.Host;
+            if (RemoteUrl.Port > 0)
+                ssh_keyscan.StartInfo.Arguments = string.Format ("-t rsa -p {0} {1}", RemoteUrl.Port, RemoteUrl.Host);
 
-                var ssh_keyscan = new Command ("ssh-keyscan", args);
-                string host_key = ssh_keyscan.StartAndReadStandardOutput ();
+            string host_key = ssh_keyscan.StartAndReadStandardOutput ();
+
+            if (ssh_keyscan.ExitCode == 0 && !string.IsNullOrWhiteSpace (host_key))
+                return host_key;
 
-                if (ssh_keyscan.ExitCode == 0 && !string.IsNullOrWhiteSpace (host_key))
-                    return host_key;
-            }
-            
             return null;
         }
-        
+
         
         string DeriveFingerprint (string public_key)
         {