Introduce the Bugs control panel, for overriding PuTTY's server

version number checks to determine the presence or absence of server
bugs.

[originally from svn r1936]

doc/config.but

@@ -1,4 +1,4 @@
-\versionid $Id: config.but,v 1.36 2002/09/08 13:25:58 jacob Exp $
+\versionid $Id: config.but,v 1.37 2002/09/08 13:28:38 simon Exp $
 
 \C{config} Configuring PuTTY
 
@@ -1356,6 +1356,10 @@ server.
 Keepalives are only supported in Telnet and SSH; the Rlogin and Raw
 protocols offer no way of implementing them.
 
+Note that if you are using SSH1 and the server has a bug that makes
+it unable to deal with SSH1 ignore messages (see
+\k{config-ssh-bug-ignore1}), enabling keepalives will have no effect.
+
 \S{config-nodelay} \q{Disable Nagle's algorithm}
 
 \cfg{winhelp-topic}{connection.nodelay}
@@ -1662,20 +1666,6 @@ If you select \q{1 only} or \q{2 only} here, PuTTY will only connect
 if the server you connect to offers the SSH protocol version you
 have specified.
 
-\S{config-ssh-macbug} \q{Imitate SSH 2 MAC bug}
-
-\cfg{winhelp-topic}{ssh.buggymac}
-
-This option \e{should} now be unnecessary. It existed in order to
-work around a bug in early versions (2.3.0 and below) of the SSH
-server software from \cw{ssh.com}. The symptom of this problem would
-be that PuTTY would die unexpectedly at the beginning of the
-session, saying \q{Incorrect MAC received on packet}.
-
-Current versions of PuTTY attempt to detect these faulty servers and
-enable the bug compatibility automatically, so you should never need
-to use this option any more.
-
 \S{config-ssh-encryption} Encryption algorithm selection
 
 \cfg{winhelp-topic}{ssh.ciphers}
@@ -1870,6 +1860,146 @@ SSH server machine can connect to the forwarded port.) Note that
 this feature is only available in the SSH 2 protocol, and not all
 SSH 2 servers support it (OpenSSH 3.0 does not, for example).
 
+\H{config-ssh-bugs} The Bugs panel
+
+Not all SSH servers work properly. Various existing servers have
+bugs in them, which can make it impossible for a client to talk to
+them unless it knows about the bug and works around it.
+
+Since most servers announce their software version number at the
+beginning of the SSH connection, PuTTY will attempt to detect which
+bugs it can expect to see in the server and automatically enable
+workarounds. However, sometimes it will make mistakes; if the server
+has been deliberately configured to conceal its version number, or
+if the server is a version which PuTTY's bug database does not know
+about, then PuTTY will not know what bugs to expect.
+
+The Bugs panel allows you to manually configure the bugs PuTTY
+expects to see in the server. Each bug can be configured in three
+states:
+
+\b \q{Off}: PuTTY will assume the server does not have the bug.
+
+\b \q{On}: PuTTY will assume the server \e{does} have the bug.
+
+\b \q{Auto}: PuTTY will use the server's version number announcement
+to try to guess whether or not the server has the bug.
+
+\S{config-ssh-bug-ignore1} \q{Chokes on SSH1 ignore messages}
+
+\cfg{winhelp-topic}{ssh.bugs.ignore1}
+
+An ignore message (SSH_MSG_IGNORE) is a message in the SSH protocol
+which can be sent from the client to the server, or from the server
+to the client, at any time. Either side is required to ignore the
+message whenever it receives it. PuTTY uses ignore messages to hide
+the password packet in SSH1, so that a listener cannot tell the
+length of the user's password; it also uses ignore messages for
+connection keepalives (see \k{config-keepalive}).
+
+If this bug is detected, PuTTY will stop using ignore messages. This
+means that keepalives will stop working, and PuTTY will have to fall
+back to a secondary defence against SSH1 password-length
+eavesdropping. See \k{config-ssh-bug-plainpw1}. If this bug is
+enabled when talking to a correct server, the session will succeed,
+but keepalives will not work and the session might be more
+vulnerable to eavesdroppers than it could be.
+
+This is an SSH1-specific bug. No known SSH2 server fails to deal
+with SSH2 ignore messages.
+
+\S{config-ssh-bug-plainpw1} \q{Refuses all SSH1 password camouflage}
+
+\cfg{winhelp-topic}{ssh.bugs.plainpw1}
+
+When talking to an SSH1 server which cannot deal with ignore
+messages (see \k{config-ssh-bug-ignore1}), PuTTY will attempt to
+disguise the length of the user's password by sending additional
+padding \e{within} the password packet. This is technically a
+violation of the SSH1 specification, and so PuTTY will only do it
+when it cannot use standards-compliant ignore messages as
+camouflage. In this sense, for a server to refuse to accept a padded
+password packet is not really a bug, but it does make life
+inconvenient if the server can also not handle ignore messages.
+
+If this \q{bug} is detected, PuTTY will have no choice but to send
+the user's password with no form of camouflage, so that an
+eavesdropping user will be easily able to find out the exact length
+of the password. If this bug is enabled when talking to a correct
+server, the session will succeed, but will be more vulnerable to
+eavesdroppers than it could be.
+
+This is an SSH1-specific bug. SSH2 is secure against this type of
+attack.
+
+\S{config-ssh-bug-rsa1} \q{Chokes on SSH1 RSA authentication}
+
+\cfg{winhelp-topic}{ssh.bugs.rsa1}
+
+Some SSH1 servers cannot deal with RSA authentication messages at
+all. If Pageant is running and contains any SSH1 keys, PuTTY will
+normally automatically try RSA authentication before falling back to
+passwords, so these servers will crash when they see the RSA attempt.
+
+If this bug is detected, PuTTY will go straight to password
+authentication. If this bug is enabled when talking to a correct
+server, the session will succeed, but of course RSA authentication
+will be impossible.
+
+This is an SSH1-specific bug.
+
+\S{config-ssh-bug-hmac2} \q{Miscomputes SSH2 HMAC keys}
+
+\cfg{winhelp-topic}{ssh.bugs.hmac2}
+
+Versions 2.3.0 and below of the SSH server software from
+\cw{ssh.com} compute the keys for their HMAC message authentication
+codes incorrectly. A typical symptom of this problem is that PuTTY
+dies unexpectedly at the beginning of the session, saying
+\q{Incorrect MAC received on packet}.
+
+If this bug is detected, PuTTY will compute its HMAC keys in the
+same way as the buggy server, so that communication will still be
+possible. If this bug is enabled when talking to a correct server,
+communication will fail.
+
+This is an SSH2-specific bug.
+
+\S{config-ssh-bug-derivekey2} \q{Miscomputes SSH2 encryption keys}
+
+\cfg{winhelp-topic}{ssh.bugs.derivekey2}
+
+Versions below 2.1.0 of the SSH server software from \cw{ssh.com}
+compute the keys for the session encryption incorrectly. This
+problem can cause various error messages, such as \q{Incoming packet
+was garbled on decryption}, or possibly even \q{Out of memory}.
+
+If this bug is detected, PuTTY will compute its encryption keys in
+the same way as the buggy server, so that communication will still
+be possible. If this bug is enabled when talking to a correct
+server, communication will fail.
+
+This is an SSH2-specific bug.
+
+\S{config-ssh-bug-ssh} \q{Requires padding on SSH2 RSA signatures}
+
+\cfg{winhelp-topic}{ssh.bugs.rsapad2}
+
+Versions below 3.3 of OpenSSH require SSH2 RSA signatures to be
+padded with zero bytes to the same length as the RSA key modulus.
+The SSH2 draft specification says that an unpadded signature MUST be
+accepted, so this is a bug. A typical symptom of this problem is
+that PuTTY mysteriously fails RSA authentication once in every few
+hundred attempts, and falls back to passwords.
+
+If this bug is detected, PuTTY will pad its signatures in the way
+OpenSSH expects. If this bug is enabled when talking to a correct
+server, it is likely that no damage will be done, since correct
+servers usually still accept padded signatures because they're used
+to talking to OpenSSH.
+
+This is an SSH2-specific bug.
+
 \H{config-file} Storing configuration in a file
 
 PuTTY does not currently support storing its configuration in a file

putty.h

@@ -368,6 +368,11 @@ typedef struct {
     int lport_acceptall; /* accept conns from hosts other than localhost */
     int rport_acceptall; /* same for remote forwarded ports (SSH2 only) */
     char portfwd[1024]; /* [LR]localport\thost:port\000[LR]localport\thost:port\000\000 */
+    /* SSH bug compatibility modes */
+    enum {
+	BUG_AUTO, BUG_OFF, BUG_ON
+    } sshbug_ignore1, sshbug_plainpw1, sshbug_rsa1,
+	sshbug_hmac2, sshbug_derivekey2, sshbug_rsapad2;
 } Config;
 
 /*

settings.c

@@ -189,7 +189,6 @@ void save_settings(char *section, int do_host, Config * cfg)
     write_setting_i(sesskey, "AuthTIS", cfg->try_tis_auth);
     write_setting_i(sesskey, "AuthKI", cfg->try_ki_auth);
     write_setting_i(sesskey, "SshProt", cfg->sshprot);
-    write_setting_i(sesskey, "BuggyMAC", cfg->buggymac);
     write_setting_i(sesskey, "SSH2DES", cfg->ssh2_des_cbc);
     write_setting_s(sesskey, "PublicKeyFile", cfg->keyfile);
     write_setting_s(sesskey, "RemoteCommand", cfg->remote_cmd);
@@ -304,7 +303,12 @@ void save_settings(char *section, int do_host, Config * cfg)
 	*p = '\0';
 	write_setting_s(sesskey, "PortForwardings", buf);
     }
-
+    write_setting_i(sesskey, "BugIgnore1", cfg->sshbug_ignore1);
+    write_setting_i(sesskey, "BugPlainPW1", cfg->sshbug_plainpw1);
+    write_setting_i(sesskey, "BugRSA1", cfg->sshbug_rsa1);
+    write_setting_i(sesskey, "BugHMAC2", cfg->sshbug_hmac2);
+    write_setting_i(sesskey, "BugDeriveKey2", cfg->sshbug_derivekey2);
+    write_setting_i(sesskey, "BugRSAPad2", cfg->sshbug_rsapad2);
     close_settings_w(sesskey);
 }
 
@@ -400,7 +404,6 @@ void load_settings(char *section, int do_host, Config * cfg)
     gprefs(sesskey, "Cipher", "\0",
 	   ciphernames, CIPHER_MAX, cfg->ssh_cipherlist);
     gppi(sesskey, "SshProt", 1, &cfg->sshprot);
-    gppi(sesskey, "BuggyMAC", 0, &cfg->buggymac);
     gppi(sesskey, "SSH2DES", 0, &cfg->ssh2_des_cbc);
     gppi(sesskey, "AuthTIS", 0, &cfg->try_tis_auth);
     gppi(sesskey, "AuthKI", 1, &cfg->try_ki_auth);
@@ -566,6 +569,20 @@ void load_settings(char *section, int do_host, Config * cfg)
 	}
 	*q = '\0';
     }
+    gppi(sesskey, "BugIgnore1", BUG_AUTO, &cfg->sshbug_ignore1);
+    gppi(sesskey, "BugPlainPW1", BUG_AUTO, &cfg->sshbug_plainpw1);
+    gppi(sesskey, "BugRSA1", BUG_AUTO, &cfg->sshbug_rsa1);
+    {
+	int i;
+	gppi(sesskey, "BugHMAC2", BUG_AUTO, &cfg->sshbug_hmac2);
+	if (cfg->sshbug_hmac2 == BUG_AUTO) {
+	    gppi(sesskey, "BuggyMAC", 0, &i);
+	    if (i == 1)
+		cfg->sshbug_hmac2 = BUG_ON;
+	}
+    }
+    gppi(sesskey, "BugDeriveKey2", BUG_AUTO, &cfg->sshbug_derivekey2);
+    gppi(sesskey, "BugRSAPad2", BUG_AUTO, &cfg->sshbug_rsapad2);
 
     close_settings_r(sesskey);
 }

ssh.c

@@ -1660,9 +1660,11 @@ static void ssh_detect_bugs(char *vstring)
 
     ssh_remote_bugs = 0;
 
-    if (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
+    if (cfg.sshbug_ignore1 == BUG_ON ||
-	!strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
+	(cfg.sshbug_ignore1 == BUG_AUTO &&
-	!strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25")) {
+	 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
+	  !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
+	  !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25")))) {
 	/*
 	 * These versions don't support SSH1_MSG_IGNORE, so we have
 	 * to use a different defence against password length
@@ -1672,7 +1674,9 @@ static void ssh_detect_bugs(char *vstring)
 	logevent("We believe remote version has SSH1 ignore bug");
     }
 
-    if (!strcmp(imp, "Cisco-1.25")) {
+    if (cfg.sshbug_plainpw1 == BUG_ON ||
+	(cfg.sshbug_plainpw1 == BUG_AUTO &&
+	 (!strcmp(imp, "Cisco-1.25")))) {
 	/*
 	 * These versions need a plain password sent; they can't
 	 * handle having a null and a random length of data after
@@ -1682,7 +1686,9 @@ static void ssh_detect_bugs(char *vstring)
 	logevent("We believe remote version needs a plain SSH1 password");
     }
 
-    if (!strcmp(imp, "Cisco-1.25")) {
+    if (cfg.sshbug_rsa1 == BUG_ON ||
+	(cfg.sshbug_rsa1 == BUG_AUTO &&
+	 (!strcmp(imp, "Cisco-1.25")))) {
 	/*
 	 * These versions apparently have no clue whatever about
 	 * RSA authentication and will panic and die if they see
@@ -1692,9 +1698,11 @@ static void ssh_detect_bugs(char *vstring)
 	logevent("We believe remote version can't handle RSA authentication");
     }
 
-    if (!strncmp(imp, "2.1.0", 5) || !strncmp(imp, "2.0.", 4) ||
+    if (cfg.sshbug_hmac2 == BUG_ON ||
-	!strncmp(imp, "2.2.0", 5) || !strncmp(imp, "2.3.0", 5) ||
+	(cfg.sshbug_hmac2 == BUG_AUTO &&
-	!strncmp(imp, "2.1 ", 4)) {
+	 (!strncmp(imp, "2.1.0", 5) || !strncmp(imp, "2.0.", 4) ||
+	  !strncmp(imp, "2.2.0", 5) || !strncmp(imp, "2.3.0", 5) ||
+	  !strncmp(imp, "2.1 ", 4)))) {
 	/*
 	 * These versions have the HMAC bug.
 	 */
@@ -1702,7 +1710,9 @@ static void ssh_detect_bugs(char *vstring)
 	logevent("We believe remote version has SSH2 HMAC bug");
     }
 
-    if (!strncmp(imp, "2.0.", 4)) {
+    if (cfg.sshbug_derivekey2 == BUG_ON ||
+	(cfg.sshbug_derivekey2 == BUG_AUTO &&
+	 (!strncmp(imp, "2.0.", 4)))) {
 	/*
 	 * These versions have the key-derivation bug (failing to
 	 * include the literal shared secret in the hashes that
@@ -1712,8 +1722,10 @@ static void ssh_detect_bugs(char *vstring)
 	logevent("We believe remote version has SSH2 key-derivation bug");
     }
 
-    if ((!strncmp(imp, "OpenSSH_2.", 10) && imp[10]>='5' && imp[10]<='9') ||
+    if (cfg.sshbug_rsapad2 == BUG_ON ||
-	(!strncmp(imp, "OpenSSH_3.", 10) && imp[10]>='0' && imp[10]<='2')) {
+	(cfg.sshbug_rsapad2 == BUG_AUTO &&
+	 ((!strncmp(imp, "OpenSSH_2.", 10) && imp[10]>='5' && imp[10]<='9') ||
+	  (!strncmp(imp, "OpenSSH_3.", 10) && imp[10]>='0' && imp[10]<='2')))){
 	/*
 	 * These versions have the SSH2 RSA padding bug.
 	 */
@@ -5787,7 +5799,8 @@ static void ssh_special(Telnet_Special code)
 	if (ssh_state == SSH_STATE_CLOSED
 	    || ssh_state == SSH_STATE_PREPACKET) return;
 	if (ssh_version == 1) {
-	    send_packet(SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
+	    if (!(ssh_remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
+		send_packet(SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
 	} else {
 	    ssh2_pkt_init(SSH2_MSG_IGNORE);
 	    ssh2_pkt_addstring_start();

winctrls.c

@@ -447,6 +447,40 @@ void staticpassedit(struct ctlpos *cp, char *stext,
     staticedit_internal(cp, stext, sid, eid, percentedit, ES_PASSWORD);
 }
 
+/*
+ * A drop-down list box on the right hand side, with a static to
+ * its left.
+ */
+void staticddl(struct ctlpos *cp, char *stext,
+	       int sid, int lid, int percentlist)
+{
+    const int height = (COMBOHEIGHT > STATICHEIGHT ?
+			COMBOHEIGHT : STATICHEIGHT);
+    RECT r;
+    int lwid, rwid, rpos;
+
+    rpos =
+	GAPBETWEEN + (100 - percentlist) * (cp->width + GAPBETWEEN) / 100;
+    lwid = rpos - 2 * GAPBETWEEN;
+    rwid = cp->width + GAPBETWEEN - rpos;
+
+    r.left = GAPBETWEEN;
+    r.top = cp->ypos + (height - STATICHEIGHT) / 2;
+    r.right = lwid;
+    r.bottom = STATICHEIGHT;
+    doctl(cp, r, "STATIC", WS_CHILD | WS_VISIBLE, 0, stext, sid);
+
+    r.left = rpos;
+    r.top = cp->ypos + (height - EDITHEIGHT) / 2;
+    r.right = rwid;
+    r.bottom = COMBOHEIGHT*4;
+    doctl(cp, r, "COMBOBOX",
+	  WS_CHILD | WS_VISIBLE | WS_TABSTOP |
+	  CBS_DROPDOWNLIST | CBS_HASSTRINGS, WS_EX_CLIENTEDGE, "", lid);
+
+    cp->ypos += height + GAPBETWEEN;
+}
+
 /*
  * A big multiline edit control with a static labelling it.
  */

windlg.c

@@ -509,7 +509,6 @@ enum { IDCX_ABOUT =
     IDC_CIPHERLIST,
     IDC_CIPHERUP,
     IDC_CIPHERDN,
-    IDC_BUGGYMAC,
     IDC_SSH2DES,
     IDC_SSHPROTSTATIC,
     IDC_SSHPROT1ONLY,
@@ -534,6 +533,23 @@ enum { IDCX_ABOUT =
     IDC_AUTHKI,
     sshauthpanelend,
 
+    sshbugspanelstart,
+    IDC_TITLE_SSHBUGS,
+    IDC_BOX_SSHBUGS1,
+    IDC_BUGS_IGNORE1,
+    IDC_BUGD_IGNORE1,
+    IDC_BUGS_PLAINPW1,
+    IDC_BUGD_PLAINPW1,
+    IDC_BUGS_RSA1,
+    IDC_BUGD_RSA1,
+    IDC_BUGS_HMAC2,
+    IDC_BUGD_HMAC2,
+    IDC_BUGS_DERIVEKEY2,
+    IDC_BUGD_DERIVEKEY2,
+    IDC_BUGS_RSAPAD2,
+    IDC_BUGD_RSAPAD2,
+    sshbugspanelend,
+
     selectionpanelstart,
     IDC_TITLE_SELECTION,
     IDC_BOX_SELECTION1,
@@ -889,8 +905,6 @@ char *help_context_cmd(int id)
       case IDC_CIPHERDN:
       case IDC_SSH2DES:
         return "JI(`',`ssh.ciphers')";
-      case IDC_BUGGYMAC:
-        return "JI(`',`ssh.buggymac')";
       case IDC_SSHPROTSTATIC:
       case IDC_SSHPROT1ONLY:
       case IDC_SSHPROT1:
@@ -985,6 +999,25 @@ char *help_context_cmd(int id)
       case IDC_RPORT_ALL:
         return "JI(`',`ssh.tunnels.portfwd.localhost')";
 
+      case IDC_BUGS_IGNORE1:
+      case IDC_BUGD_IGNORE1:
+	return "JI(`',`ssh.bugs.ignore1')";
+      case IDC_BUGS_PLAINPW1:
+      case IDC_BUGD_PLAINPW1:
+	return "JI(`',`ssh.bugs.plainpw1')";
+      case IDC_BUGS_RSA1:
+      case IDC_BUGD_RSA1:
+	return "JI(`',`ssh.bugs.rsa1')";
+      case IDC_BUGS_HMAC2:
+      case IDC_BUGD_HMAC2:
+	return "JI(`',`ssh.bugs.hmac2')";
+      case IDC_BUGS_DERIVEKEY2:
+      case IDC_BUGD_DERIVEKEY2:
+	return "JI(`',`ssh.bugs.derivekey2')";
+      case IDC_BUGS_RSAPAD2:
+      case IDC_BUGD_RSAPAD2:
+	return "JI(`',`ssh.bugs.rsapad2')";
+
       default:
         return NULL;
     }
@@ -1149,7 +1182,6 @@ static void init_dlg_ctrls(HWND hwnd, int keepsess)
     SetDlgItemText(hwnd, IDC_LOGEDIT, cfg.username);
     CheckDlgButton(hwnd, IDC_NOPTY, cfg.nopty);
     CheckDlgButton(hwnd, IDC_COMPRESS, cfg.compression);
-    CheckDlgButton(hwnd, IDC_BUGGYMAC, cfg.buggymac);
     CheckDlgButton(hwnd, IDC_SSH2DES, cfg.ssh2_des_cbc);
     CheckDlgButton(hwnd, IDC_AGENTFWD, cfg.agentfwd);
     CheckDlgButton(hwnd, IDC_CHANGEUSER, cfg.change_username);
@@ -1288,6 +1320,50 @@ static void init_dlg_ctrls(HWND hwnd, int keepsess)
     SetDlgItemText(hwnd, IDC_PROXYPASSEDIT, cfg.proxy_password);
     CheckRadioButton(hwnd, IDC_PROXYSOCKSVER5, IDC_PROXYSOCKSVER4,
 		     cfg.proxy_socks_version == 4 ? IDC_PROXYSOCKSVER4 : IDC_PROXYSOCKSVER5);
+
+    /* SSH bugs config */
+    SendDlgItemMessage(hwnd, IDC_BUGD_IGNORE1, CB_RESETCONTENT, 0, 0);
+    SendDlgItemMessage(hwnd, IDC_BUGD_IGNORE1, CB_ADDSTRING, 0, (LPARAM)"Auto");
+    SendDlgItemMessage(hwnd, IDC_BUGD_IGNORE1, CB_ADDSTRING, 0, (LPARAM)"Off");
+    SendDlgItemMessage(hwnd, IDC_BUGD_IGNORE1, CB_ADDSTRING, 0, (LPARAM)"On");
+    SendDlgItemMessage(hwnd, IDC_BUGD_IGNORE1, CB_SETCURSEL,
+		       cfg.sshbug_ignore1 == BUG_ON ? 2 :
+		       cfg.sshbug_ignore1 == BUG_OFF ? 1 : 0, 0);
+    SendDlgItemMessage(hwnd, IDC_BUGD_PLAINPW1, CB_RESETCONTENT, 0, 0);
+    SendDlgItemMessage(hwnd, IDC_BUGD_PLAINPW1, CB_ADDSTRING, 0, (LPARAM)"Auto");
+    SendDlgItemMessage(hwnd, IDC_BUGD_PLAINPW1, CB_ADDSTRING, 0, (LPARAM)"Off");
+    SendDlgItemMessage(hwnd, IDC_BUGD_PLAINPW1, CB_ADDSTRING, 0, (LPARAM)"On");
+    SendDlgItemMessage(hwnd, IDC_BUGD_PLAINPW1, CB_SETCURSEL,
+		       cfg.sshbug_plainpw1 == BUG_ON ? 2 :
+		       cfg.sshbug_plainpw1 == BUG_OFF ? 1 : 0, 0);
+    SendDlgItemMessage(hwnd, IDC_BUGD_RSA1, CB_RESETCONTENT, 0, 0);
+    SendDlgItemMessage(hwnd, IDC_BUGD_RSA1, CB_ADDSTRING, 0, (LPARAM)"Auto");
+    SendDlgItemMessage(hwnd, IDC_BUGD_RSA1, CB_ADDSTRING, 0, (LPARAM)"Off");
+    SendDlgItemMessage(hwnd, IDC_BUGD_RSA1, CB_ADDSTRING, 0, (LPARAM)"On");
+    SendDlgItemMessage(hwnd, IDC_BUGD_RSA1, CB_SETCURSEL,
+		       cfg.sshbug_rsa1 == BUG_ON ? 2 :
+		       cfg.sshbug_rsa1 == BUG_OFF ? 1 : 0, 0);
+    SendDlgItemMessage(hwnd, IDC_BUGD_HMAC2, CB_RESETCONTENT, 0, 0);
+    SendDlgItemMessage(hwnd, IDC_BUGD_HMAC2, CB_ADDSTRING, 0, (LPARAM)"Auto");
+    SendDlgItemMessage(hwnd, IDC_BUGD_HMAC2, CB_ADDSTRING, 0, (LPARAM)"Off");
+    SendDlgItemMessage(hwnd, IDC_BUGD_HMAC2, CB_ADDSTRING, 0, (LPARAM)"On");
+    SendDlgItemMessage(hwnd, IDC_BUGD_HMAC2, CB_SETCURSEL,
+		       cfg.sshbug_hmac2 == BUG_ON ? 2 :
+		       cfg.sshbug_hmac2 == BUG_OFF ? 1 : 0, 0);
+    SendDlgItemMessage(hwnd, IDC_BUGD_DERIVEKEY2, CB_RESETCONTENT, 0, 0);
+    SendDlgItemMessage(hwnd, IDC_BUGD_DERIVEKEY2, CB_ADDSTRING, 0, (LPARAM)"Auto");
+    SendDlgItemMessage(hwnd, IDC_BUGD_DERIVEKEY2, CB_ADDSTRING, 0, (LPARAM)"Off");
+    SendDlgItemMessage(hwnd, IDC_BUGD_DERIVEKEY2, CB_ADDSTRING, 0, (LPARAM)"On");
+    SendDlgItemMessage(hwnd, IDC_BUGD_DERIVEKEY2, CB_SETCURSEL,
+		       cfg.sshbug_derivekey2 == BUG_ON ? 2 :
+		       cfg.sshbug_derivekey2 == BUG_OFF ? 1 : 0, 0);
+    SendDlgItemMessage(hwnd, IDC_BUGD_RSAPAD2, CB_RESETCONTENT, 0, 0);
+    SendDlgItemMessage(hwnd, IDC_BUGD_RSAPAD2, CB_ADDSTRING, 0, (LPARAM)"Auto");
+    SendDlgItemMessage(hwnd, IDC_BUGD_RSAPAD2, CB_ADDSTRING, 0, (LPARAM)"Off");
+    SendDlgItemMessage(hwnd, IDC_BUGD_RSAPAD2, CB_ADDSTRING, 0, (LPARAM)"On");
+    SendDlgItemMessage(hwnd, IDC_BUGD_RSAPAD2, CB_SETCURSEL,
+		       cfg.sshbug_rsapad2 == BUG_ON ? 2 :
+		       cfg.sshbug_rsapad2 == BUG_OFF ? 1 : 0, 0);
 }
 
 struct treeview_faff {
@@ -1833,8 +1909,6 @@ static void create_controls(HWND hwnd, int dlgtype, int panel)
 		      "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",
-		     IDC_BUGGYMAC);
 	    endbox(&cp);
 	    beginbox(&cp, "Encryption options", IDC_BOX_SSH3);
 	    prefslist(&cipherlist, &cp, "Encryption cipher &selection policy:",
@@ -1872,6 +1946,31 @@ static void create_controls(HWND hwnd, int dlgtype, int panel)
 	}
     }
 
+    if (panel == sshbugspanelstart) {
+	/* The SSH bugs panel. Accelerators used: [acgoh] isrmep */
+	struct ctlpos cp;
+	ctlposinit(&cp, hwnd, 80, 3, 13);
+	if (dlgtype == 0) {
+	    bartitle(&cp, "Workarounds for SSH server bugs",
+		     IDC_TITLE_SSHBUGS);
+	    beginbox(&cp, "Detection of known bugs in SSH servers",
+		     IDC_BOX_SSHBUGS1);
+	    staticddl(&cp, "Chokes on SSH1 &ignore messages",
+		      IDC_BUGS_IGNORE1, IDC_BUGD_IGNORE1, 20);
+	    staticddl(&cp, "Refuses all SSH1 pa&ssword camouflage",
+		      IDC_BUGS_PLAINPW1, IDC_BUGD_PLAINPW1, 20);
+	    staticddl(&cp, "Chokes on SSH1 &RSA authentication",
+		      IDC_BUGS_RSA1, IDC_BUGD_RSA1, 20);
+	    staticddl(&cp, "Miscomputes SSH2 H&MAC keys",
+		      IDC_BUGS_HMAC2, IDC_BUGD_HMAC2, 20);
+	    staticddl(&cp, "Miscomputes SSH2 &encryption keys",
+		      IDC_BUGS_DERIVEKEY2, IDC_BUGD_DERIVEKEY2, 20);
+	    staticddl(&cp, "Requires &padding on SSH2 RSA signatures",
+		      IDC_BUGS_RSAPAD2, IDC_BUGD_RSAPAD2, 20);
+	    endbox(&cp);
+	}
+    }
+
     if (panel == tunnelspanelstart) {
 	/* The Tunnels panel. Accelerators used: [acgoh] deilmrstxp */
 	struct ctlpos cp;
@@ -2048,6 +2147,7 @@ static int GenericMainDlgProc(HWND hwnd, UINT msg,
 		/* XXX make it closed by default? */
 		treeview_insert(&tvfaff, 2, "Auth");
 		treeview_insert(&tvfaff, 2, "Tunnels");
+		treeview_insert(&tvfaff, 2, "Bugs");
 	    }
 	}
 
@@ -2133,6 +2233,8 @@ static int GenericMainDlgProc(HWND hwnd, UINT msg,
 		create_controls(hwnd, dlgtype, sshpanelstart);
 	    if (!strcmp(buffer, "Auth"))
 		create_controls(hwnd, dlgtype, sshauthpanelstart);
+	    if (!strcmp(buffer, "Bugs"))
+		create_controls(hwnd, dlgtype, sshbugspanelstart);
 	    if (!strcmp(buffer, "Selection"))
 		create_controls(hwnd, dlgtype, selectionpanelstart);
 	    if (!strcmp(buffer, "Colours"))
@@ -3063,12 +3165,6 @@ static int GenericMainDlgProc(HWND hwnd, UINT msg,
 			cfg.compression =
 			IsDlgButtonChecked(hwnd, IDC_COMPRESS);
 		break;
-	      case IDC_BUGGYMAC:
-		if (HIWORD(wParam) == BN_CLICKED ||
-		    HIWORD(wParam) == BN_DOUBLECLICKED)
-			cfg.buggymac =
-			IsDlgButtonChecked(hwnd, IDC_BUGGYMAC);
-		break;
 	      case IDC_SSH2DES:
 		if (HIWORD(wParam) == BN_CLICKED ||
 		    HIWORD(wParam) == BN_DOUBLECLICKED)
@@ -3441,6 +3537,54 @@ static int GenericMainDlgProc(HWND hwnd, UINT msg,
 		  disaster2:;
 		}
 		break;
+	      case IDC_BUGD_IGNORE1:
+		if (HIWORD(wParam) == CBN_SELCHANGE) {
+		    int index = SendDlgItemMessage(hwnd, IDC_BUGD_IGNORE1,
+						   CB_GETCURSEL, 0, 0);
+		    cfg.sshbug_ignore1 = (index == 0 ? BUG_AUTO :
+					  index == 1 ? BUG_OFF : BUG_ON);
+		}
+		break;
+	      case IDC_BUGD_PLAINPW1:
+		if (HIWORD(wParam) == CBN_SELCHANGE) {
+		    int index = SendDlgItemMessage(hwnd, IDC_BUGD_PLAINPW1,
+						   CB_GETCURSEL, 0, 0);
+		    cfg.sshbug_plainpw1 = (index == 0 ? BUG_AUTO :
+					   index == 1 ? BUG_OFF : BUG_ON);
+		}
+		break;
+	      case IDC_BUGD_RSA1:
+		if (HIWORD(wParam) == CBN_SELCHANGE) {
+		    int index = SendDlgItemMessage(hwnd, IDC_BUGD_RSA1,
+						   CB_GETCURSEL, 0, 0);
+		    cfg.sshbug_rsa1 = (index == 0 ? BUG_AUTO :
+				       index == 1 ? BUG_OFF : BUG_ON);
+		}
+		break;
+	      case IDC_BUGD_HMAC2:
+		if (HIWORD(wParam) == CBN_SELCHANGE) {
+		    int index = SendDlgItemMessage(hwnd, IDC_BUGD_HMAC2,
+						   CB_GETCURSEL, 0, 0);
+		    cfg.sshbug_hmac2 = (index == 0 ? BUG_AUTO :
+					index == 1 ? BUG_OFF : BUG_ON);
+		}
+		break;
+	      case IDC_BUGD_DERIVEKEY2:
+		if (HIWORD(wParam) == CBN_SELCHANGE) {
+		    int index = SendDlgItemMessage(hwnd, IDC_BUGD_DERIVEKEY2,
+						   CB_GETCURSEL, 0, 0);
+		    cfg.sshbug_derivekey2 = (index == 0 ? BUG_AUTO :
+					     index == 1 ? BUG_OFF : BUG_ON);
+		}
+		break;
+	      case IDC_BUGD_RSAPAD2:
+		if (HIWORD(wParam) == CBN_SELCHANGE) {
+		    int index = SendDlgItemMessage(hwnd, IDC_BUGD_RSAPAD2,
+						   CB_GETCURSEL, 0, 0);
+		    cfg.sshbug_rsapad2 = (index == 0 ? BUG_AUTO :
+					  index == 1 ? BUG_OFF : BUG_ON);
+		}
+		break;
 	    }
 	return 0;
       case WM_HELP:

winstuff.h

@@ -64,6 +64,8 @@ void static2btn(struct ctlpos *cp, char *stext, int sid,
 		char *btext1, int bid1, char *btext2, int bid2);
 void staticedit(struct ctlpos *cp, char *stext,
 		int sid, int eid, int percentedit);
+void staticddl(struct ctlpos *cp, char *stext,
+	       int sid, int lid, int percentlist);
 void combobox(struct ctlpos *cp, char *text, int staticid, int listid);
 void staticpassedit(struct ctlpos *cp, char *stext,
 		    int sid, int eid, int percentedit);