Single-DES encryption, patch courtesy of Murphy Lam

[originally from svn r253]

putty.h

@@ -97,7 +97,7 @@ typedef struct {
     int close_on_exit;
     /* SSH options */
     int nopty;
-    enum { CIPHER_3DES, CIPHER_BLOWFISH } cipher;
+    enum { CIPHER_3DES, CIPHER_BLOWFISH, CIPHER_DES } cipher;
     /* Telnet options */
     char termtype[32];
     char termspeed[32];

ssh.c

@@ -213,6 +213,21 @@ static void s_wrpkt(void) {
     s_write(pktout.data, biglen+4);
 }
 
+static int ssh_versioncmp(char *a, char *b) {
+    char *ae, *be;
+    unsigned long av, bv;
+
+    av = strtoul(a, &ae);
+    bv = strtoul(b, &be);
+    if (av != bv) return (av < bv ? -1 : +1);
+    if (*ae == '.') ae++;
+    if (*be == '.') be++;
+    av = strtoul(ae, &ae);
+    bv = strtoul(be, &be);
+    if (av != bv) return (av < bv ? -1 : +1);
+    return 0;
+}
+
 static int do_ssh_init(void) {
     char c;
     char version[10];
@@ -248,8 +263,8 @@ static int do_ssh_init(void) {
 	    break;
     }
 
-    sprintf(vstring, "SSH-%s-7.7.7\n",
+    sprintf(vstring, "SSH-%s-PuTTY\n",
-	    (strcmp(version, "1.5") <= 0 ? version : "1.5"));
+	    (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"));
     s_write(vstring, strlen(vstring));
     return 1;
 }
@@ -265,6 +280,7 @@ static void ssh_protocol(unsigned char *in, int inlen, int ispkt) {
     int cipher_type;
 
     extern struct ssh_cipher ssh_3des;
+    extern struct ssh_cipher ssh_des;
     extern struct ssh_cipher ssh_blowfish;
 
     crBegin;
@@ -322,6 +338,7 @@ static void ssh_protocol(unsigned char *in, int inlen, int ispkt) {
     }
 
     cipher_type = cfg.cipher == CIPHER_BLOWFISH ? SSH_CIPHER_BLOWFISH :
+                  cfg.cipher == CIPHER_DES ? SSH_CIPHER_DES : 
                   SSH_CIPHER_3DES;
     if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
 	c_write("Selected cipher not supported, falling back to 3DES\r\n", 53);
@@ -341,6 +358,7 @@ static void ssh_protocol(unsigned char *in, int inlen, int ispkt) {
     free(rsabuf);
 
     cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish :
+             cipher_type == SSH_CIPHER_DES ? &ssh_des :
              &ssh_3des;
     cipher->sesskey(session_key);
 

ssh.h

@@ -1,6 +1,7 @@
 #include <string.h>
 
 #define SSH_CIPHER_IDEA		1
+#define SSH_CIPHER_DES		2
 #define SSH_CIPHER_3DES		3
 #define SSH_CIPHER_BLOWFISH	6
 

sshdes.c

@@ -673,6 +673,27 @@ struct ssh_cipher ssh_3des = {
     des3_decrypt_blk
 };
 
+static void des_sesskey(unsigned char *key) {
+    des_set_key(key, &ekey1);
+    memset(eiv1, 0, sizeof(eiv1));
+    des_set_key(key, &dkey1);
+    memset(div1, 0, sizeof(div1));
+}
+
+static void des_encrypt_blk(unsigned char *blk, int len) {
+    des_cbc_encrypt(&ekey1, eiv1, blk, blk, len);
+}
+
+static void des_decrypt_blk(unsigned char *blk, int len) {
+    des_cbc_decrypt(&dkey1, div1, blk, blk, len);
+}
+
+struct ssh_cipher ssh_des = {
+    des_sesskey,
+    des_encrypt_blk,
+    des_decrypt_blk
+};
+
 #ifdef DES_TEST
 
 void des_encrypt_buf(DESContext *ks, unsigned char *out, 

win_res.h

@@ -99,6 +99,7 @@
 #define IDC3_CIPHERSTATIC 1019
 #define IDC3_CIPHER3DES	1020
 #define IDC3_CIPHERBLOWF 1021
+#define IDC3_CIPHERDES  1022
 
 #define IDC4_MBSTATIC   1001
 #define IDC4_MBWINDOWS  1002

win_res.rc

@@ -163,6 +163,7 @@ BEGIN
     LTEXT "Cipher:", IDC3_CIPHERSTATIC, 3, 50, 40, 8
     AUTORADIOBUTTON "&3DES", IDC3_CIPHER3DES, 46, 50, 35, 10, WS_GROUP
     AUTORADIOBUTTON "&Blowfish", IDC3_CIPHERBLOWF, 84, 50, 40, 10
+    AUTORADIOBUTTON "&DES", IDC3_CIPHERDES, 127, 50, 30, 10
 END
 
 IDD_PANEL4 DIALOG DISCARDABLE 6, 30, 168, 163

windlg.c

@@ -148,7 +148,7 @@ static void save_settings (char *section, int do_host) {
     wpps (sesskey, "UserName", cfg.username);
     wppi (sesskey, "NoPTY", cfg.nopty);
     wpps (sesskey, "Cipher", cfg.cipher == CIPHER_BLOWFISH ? "blowfish" :
-                             "3des");
+                             cfg.cipher == CIPHER_DES ? "des" : "3des");
     wppi (sesskey, "RFCEnviron", cfg.rfc_environ);
     wppi (sesskey, "BackspaceIsDelete", cfg.bksp_is_delete);
     wppi (sesskey, "RXVTHomeEnd", cfg.rxvt_homeend);
@@ -270,6 +270,8 @@ static void load_settings (char *section, int do_host) {
 	gpps (sesskey, "Cipher", "3des", cipher, 10);
 	if (!strcmp(cipher, "blowfish"))
 	    cfg.cipher = CIPHER_BLOWFISH;
+	else if (!strcmp(cipher, "des"))
+	    cfg.cipher = CIPHER_DES;
 	else
 	    cfg.cipher = CIPHER_3DES;
     }
@@ -874,8 +876,10 @@ static int CALLBACK SshProc (HWND hwnd, UINT msg,
 	SetDlgItemText (hwnd, IDC3_TTEDIT, cfg.termtype);
 	SetDlgItemText (hwnd, IDC3_LOGEDIT, cfg.username);
 	CheckDlgButton (hwnd, IDC3_NOPTY, cfg.nopty);
-	CheckRadioButton (hwnd, IDC3_CIPHER3DES, IDC3_CIPHERBLOWF,
+	CheckRadioButton (hwnd, IDC3_CIPHER3DES, IDC3_CIPHERDES,
 			  cfg.cipher == CIPHER_BLOWFISH ? IDC3_CIPHERBLOWF :
+			  cfg.cipher == CIPHER_DES ? IDC3_CIPHERDES :
+
 			  IDC3_CIPHER3DES);
 	break;
       case WM_COMMAND:
@@ -897,12 +901,15 @@ static int CALLBACK SshProc (HWND hwnd, UINT msg,
 	    break;
 	  case IDC3_CIPHER3DES:
 	  case IDC3_CIPHERBLOWF:
+	  case IDC3_CIPHERDES:
 	    if (HIWORD(wParam) == BN_CLICKED ||
 		HIWORD(wParam) == BN_DOUBLECLICKED) {
 		if (IsDlgButtonChecked (hwnd, IDC3_CIPHER3DES))
 		    cfg.cipher = CIPHER_3DES;
 		else if (IsDlgButtonChecked (hwnd, IDC3_CIPHERBLOWF))
 		    cfg.cipher = CIPHER_BLOWFISH;
+		else if (IsDlgButtonChecked (hwnd, IDC3_CIPHERDES))
+		    cfg.cipher = CIPHER_DES;
 	    }
 	    break;
 	}