From 38d228a25df956ea1c28bd5d5b234bd07b0140a7 Mon Sep 17 00:00:00 2001
From: simon <simon@cda61777-01e9-0310-a592-d414129be87e>
Date: Wed, 7 Aug 2002 17:48:26 +0000
Subject: [PATCH] Add an option to force SSH1 protocol only. Partly for
 symmetry; mostly because I'm about to want it for the -1 command line option.

git-svn-id: svn://svn.tartarus.org/sgt/putty@1816 cda61777-01e9-0310-a592-d414129be87e
---
 ssh.c    | 30 ++++++++++++++++++++----------
 windlg.c | 13 ++++++++++---
 2 files changed, 30 insertions(+), 13 deletions(-)

diff --git a/ssh.c b/ssh.c
index 1885088f..a3ac60b4 100644
--- a/ssh.c
+++ b/ssh.c
@@ -1710,6 +1710,7 @@ static int do_ssh_init(unsigned char c)
     static int vstrsize;
     static char *vlog;
     static int i;
+    static int proto1, proto2;
 
     crBegin;
 
@@ -1766,12 +1767,26 @@ static int do_ssh_init(unsigned char c)
     sfree(vlog);
 
     /*
-     * Server version "1.99" means we can choose whether we use v1
-     * or v2 protocol. Choice is based on cfg.sshprot.
+     * Decide which SSH protocol version to support.
      */
-    if (ssh_versioncmp(version, cfg.sshprot == 1 ? "2.0" : "1.99") >= 0) {
+
+    /* Anything strictly below "2.0" means protocol 1 is supported. */
+    proto1 = ssh_versioncmp(version, "2.0") < 0;
+    /* Anything greater or equal to "1.99" means protocol 2 is supported. */
+    proto2 = ssh_versioncmp(version, "1.99") > 0;
+
+    if (cfg.sshprot == 0 && !proto1) {
+	bombout(("SSH protocol version 1 required by user but not provided by server"));
+	crReturn(0);
+    }
+    if (cfg.sshprot == 3 && !proto2) {
+	bombout(("SSH protocol version 2 required by user but not provided by server"));
+	crReturn(0);
+    }
+
+    if (proto2 && (cfg.sshprot == 2 || !proto1)) {
 	/*
-	 * This is a v2 server. Begin v2 protocol.
+	 * Use v2 protocol.
 	 */
 	char verstring[80], vlog[100];
 	sprintf(verstring, "SSH-2.0-%s", sshver);
@@ -1791,7 +1806,7 @@ static int do_ssh_init(unsigned char c)
 	s_rdpkt = ssh2_rdpkt;
     } else {
 	/*
-	 * This is a v1 server. Begin v1 protocol.
+	 * Use v1 protocol.
 	 */
 	char verstring[80], vlog[100];
 	sprintf(verstring, "SSH-%s-%s",
@@ -1800,11 +1815,6 @@ static int do_ssh_init(unsigned char c)
 	sprintf(vlog, "We claim version: %s", verstring);
 	logevent(vlog);
 	strcat(verstring, "\n");
-	
-	if (cfg.sshprot == 3) {
-	    bombout(("SSH protocol version 2 required by user but not provided by server"));
-	    crReturn(0);
-	}
 
 	logevent("Using SSH protocol version 1");
 	sk_write(s, verstring, strlen(verstring));
diff --git a/windlg.c b/windlg.c
index 2876d9db..474a0547 100644
--- a/windlg.c
+++ b/windlg.c
@@ -512,6 +512,7 @@ enum { IDCX_ABOUT =
     IDC_BUGGYMAC,
     IDC_SSH2DES,
     IDC_SSHPROTSTATIC,
+    IDC_SSHPROT1ONLY,
     IDC_SSHPROT1,
     IDC_SSHPROT2,
     IDC_SSHPROT2ONLY,
@@ -891,6 +892,7 @@ char *help_context_cmd(int id)
       case IDC_BUGGYMAC:
         return "JI(`',`ssh.buggymac')";
       case IDC_SSHPROTSTATIC:
+      case IDC_SSHPROT1ONLY:
       case IDC_SSHPROT1:
       case IDC_SSHPROT2:
       case IDC_SSHPROT2ONLY:
@@ -1151,9 +1153,10 @@ static void init_dlg_ctrls(HWND hwnd, int keepsess)
     CheckDlgButton(hwnd, IDC_SSH2DES, cfg.ssh2_des_cbc);
     CheckDlgButton(hwnd, IDC_AGENTFWD, cfg.agentfwd);
     CheckDlgButton(hwnd, IDC_CHANGEUSER, cfg.change_username);
-    CheckRadioButton(hwnd, IDC_SSHPROT1, IDC_SSHPROT2ONLY,
+    CheckRadioButton(hwnd, IDC_SSHPROT1ONLY, IDC_SSHPROT2ONLY,
 		     cfg.sshprot == 1 ? IDC_SSHPROT1 :
-		     cfg.sshprot == 2 ? IDC_SSHPROT2 : IDC_SSHPROT2ONLY);
+		     cfg.sshprot == 2 ? IDC_SSHPROT2 :
+		     cfg.sshprot == 3 ? IDC_SSHPROT2ONLY : IDC_SSHPROT1ONLY);
     CheckDlgButton(hwnd, IDC_AUTHTIS, cfg.try_tis_auth);
     CheckDlgButton(hwnd, IDC_AUTHKI, cfg.try_ki_auth);
     SetDlgItemText(hwnd, IDC_PKEDIT, cfg.keyfile);
@@ -1826,7 +1829,8 @@ static void create_controls(HWND hwnd, int dlgtype, int panel)
 	    checkbox(&cp, "Don't allocate a &pseudo-terminal", IDC_NOPTY);
 	    checkbox(&cp, "Enable compr&ession", IDC_COMPRESS);
 	    radioline(&cp, "Preferred SSH protocol version:",
-		      IDC_SSHPROTSTATIC, 3,
+		      IDC_SSHPROTSTATIC, 4,
+		      "1 on&ly", IDC_SSHPROT1ONLY,
 		      "&1", IDC_SSHPROT1, "&2", IDC_SSHPROT2,
 		      "2 o&nly", IDC_SSHPROT2ONLY, NULL);
 	    checkbox(&cp, "&Imitate SSH 2 MAC bug in commercial <= v2.3.x",
@@ -3090,11 +3094,14 @@ static int GenericMainDlgProc(HWND hwnd, UINT msg,
 				 cfg.ssh_cipherlist, CIPHER_MAX,
 				 0, hwnd, wParam, lParam);
 		break;
+	      case IDC_SSHPROT1ONLY:
 	      case IDC_SSHPROT1:
 	      case IDC_SSHPROT2:
       	      case IDC_SSHPROT2ONLY:
 		if (HIWORD(wParam) == BN_CLICKED ||
 		    HIWORD(wParam) == BN_DOUBLECLICKED) {
+		    if (IsDlgButtonChecked(hwnd, IDC_SSHPROT1ONLY))
+			cfg.sshprot = 0;
 		    if (IsDlgButtonChecked(hwnd, IDC_SSHPROT1))
 			cfg.sshprot = 1;
 		    else if (IsDlgButtonChecked(hwnd, IDC_SSHPROT2))
-- 
2.11.0