upstream commit

Drop compatibility hacks for some ancient SSH
implementations, including ssh.com <=2.* and OpenSSH <= 3.*.

These versions were all released in or before 2001 and predate the
final SSH RFCs. The hacks in question aren't necessary for RFC-
compliant SSH implementations.

ok markus@

OpenBSD-Commit-ID: 4be81c67db57647f907f4e881fb9341448606138

17 files changed, 111 insertions, 303 deletions

diff --git a/auth2-hostbased.c b/auth2-hostbased.c
index 8112cfaa3..8996f7e05 100644
--- a/auth2-hostbased.c
+++ b/auth2-hostbased.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth2-hostbased.c,v 1.32 2017/12/18 02:25:15 djm Exp $ */
+/* $OpenBSD: auth2-hostbased.c,v 1.33 2018/01/23 05:27:21 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -62,7 +62,7 @@ userauth_hostbased(struct ssh *ssh)
         Authctxt *authctxt = ssh->authctxt;
         struct sshbuf *b;
         struct sshkey *key = NULL;
-        char *pkalg, *cuser, *chost, *service;
+        char *pkalg, *cuser, *chost;
         u_char *pkblob, *sig;
         size_t alen, blen, slen;
         int r, pktype, authenticated = 0;
@@ -118,15 +118,13 @@ userauth_hostbased(struct ssh *ssh)
                 goto done;
         }
 
-        service = ssh->compat & SSH_BUG_HBSERVICE ? "ssh-userauth" :
-            authctxt->service;
         if ((b = sshbuf_new()) == NULL)
                 fatal("%s: sshbuf_new failed", __func__);
         /* reconstruct packet */
         if ((r = sshbuf_put_string(b, session_id2, session_id2_len)) != 0 ||
             (r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
             (r = sshbuf_put_cstring(b, authctxt->user)) != 0 ||
-            (r = sshbuf_put_cstring(b, service)) != 0 ||
+            (r = sshbuf_put_cstring(b, authctxt->service)) != 0 ||
             (r = sshbuf_put_cstring(b, "hostbased")) != 0 ||
             (r = sshbuf_put_string(b, pkalg, alen)) != 0 ||
             (r = sshbuf_put_string(b, pkblob, blen)) != 0 ||
diff --git a/auth2-pubkey.c b/auth2-pubkey.c
index 0713a9de8..e64982283 100644
--- a/auth2-pubkey.c
+++ b/auth2-pubkey.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth2-pubkey.c,v 1.74 2017/12/21 00:00:28 djm Exp $ */
+/* $OpenBSD: auth2-pubkey.c,v 1.75 2018/01/23 05:27:21 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -100,26 +100,10 @@ userauth_pubkey(struct ssh *ssh)
                 debug2("%s: disabled because of invalid user", __func__);
                 return 0;
         }
-        if ((r = sshpkt_get_u8(ssh, &have_sig)) != 0)
-                fatal("%s: sshpkt_get_u8 failed: %s", __func__, ssh_err(r));
-        if (ssh->compat & SSH_BUG_PKAUTH) {
-                debug2("%s: SSH_BUG_PKAUTH", __func__);
-                if ((b = sshbuf_new()) == NULL)
-                        fatal("%s: sshbuf_new failed", __func__);
-                /* no explicit pkalg given */
-                /* so we have to extract the pkalg from the pkblob */
-                /* XXX use sshbuf_from() */
-                if ((r = sshpkt_get_string(ssh, &pkblob, &blen)) != 0 ||
-                    (r = sshbuf_put(b, pkblob, blen)) != 0 ||
-                    (r = sshbuf_get_cstring(b, &pkalg, NULL)) != 0)
-                        fatal("%s: failed: %s", __func__, ssh_err(r));
-                sshbuf_free(b);
-        } else {
-                if ((r = sshpkt_get_cstring(ssh, &pkalg, NULL)) != 0 ||
-                    (r = sshpkt_get_string(ssh, &pkblob, &blen)) != 0)
-                        fatal("%s: sshpkt_get_cstring failed: %s",
-                            __func__, ssh_err(r));
-        }
+        if ((r = sshpkt_get_u8(ssh, &have_sig)) != 0 ||
+            (r = sshpkt_get_cstring(ssh, &pkalg, NULL)) != 0 ||
+            (r = sshpkt_get_string(ssh, &pkblob, &blen)) != 0)
+                fatal("%s: parse request failed: %s", __func__, ssh_err(r));
         pktype = sshkey_type_from_name(pkalg);
         if (pktype == KEY_UNSPEC) {
                 /* this is perfectly legal */
@@ -188,22 +172,11 @@ userauth_pubkey(struct ssh *ssh)
                     authctxt->style ? authctxt->style : "");
                 if ((r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
                     (r = sshbuf_put_cstring(b, userstyle)) != 0 ||
-                    (r = sshbuf_put_cstring(b, ssh->compat & SSH_BUG_PKSERVICE ?
-                    "ssh-userauth" : authctxt->service)) != 0)
-                        fatal("%s: build packet failed: %s",
-                            __func__, ssh_err(r));
-                if (ssh->compat & SSH_BUG_PKAUTH) {
-                        if ((r = sshbuf_put_u8(b, have_sig)) != 0)
-                                fatal("%s: build packet failed: %s",
-                                    __func__, ssh_err(r));
-                } else {
-                        if ((r = sshbuf_put_cstring(b, "publickey")) != 0 ||
-                            (r = sshbuf_put_u8(b, have_sig)) != 0 ||
-                            (r = sshbuf_put_cstring(b, pkalg) != 0))
-                                fatal("%s: build packet failed: %s",
-                                    __func__, ssh_err(r));
-                }
-                if ((r = sshbuf_put_string(b, pkblob, blen)) != 0)
+                    (r = sshbuf_put_cstring(b, authctxt->service)) != 0 ||
+                    (r = sshbuf_put_cstring(b, "publickey")) != 0 ||
+                    (r = sshbuf_put_u8(b, have_sig)) != 0 ||
+                    (r = sshbuf_put_cstring(b, pkalg) != 0) ||
+                    (r = sshbuf_put_string(b, pkblob, blen)) != 0)
                         fatal("%s: build packet failed: %s",
                             __func__, ssh_err(r));
 #ifdef DEBUG_PK
diff --git a/auth2.c b/auth2.c
index 862e09960..4f5b481c9 100644
--- a/auth2.c
+++ b/auth2.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth2.c,v 1.143 2017/06/24 06:34:38 djm Exp $ */
+/* $OpenBSD: auth2.c,v 1.144 2018/01/23 05:27:21 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -153,7 +153,7 @@ userauth_banner(void)
 {
         char *banner = NULL;
 
-        if (options.banner == NULL || (datafellows & SSH_BUG_BANNER) != 0)
+        if (options.banner == NULL)
                 return;
 
         if ((banner = PRIVSEP(auth2_read_banner())) == NULL)
diff --git a/authfd.c b/authfd.c
index a460fa350..ac635dff9 100644
--- a/authfd.c
+++ b/authfd.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: authfd.c,v 1.105 2017/07/01 13:50:45 djm Exp $ */
+/* $OpenBSD: authfd.c,v 1.106 2018/01/23 05:27:21 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -353,8 +353,6 @@ ssh_agent_sign(int sock, const struct sshkey *key,
 
         if (datalen > SSH_KEY_MAX_SIGN_DATA_SIZE)
                 return SSH_ERR_INVALID_ARGUMENT;
-        if (compat & SSH_BUG_SIGBLOB)
-                flags |= SSH_AGENT_OLD_SIGNATURE;
         if ((msg = sshbuf_new()) == NULL)
                 return SSH_ERR_ALLOC_FAIL;
         if ((r = sshkey_to_blob(key, &blob, &blen)) != 0)
diff --git a/channels.c b/channels.c
index c2706ace7..1c381e0e2 100644
--- a/channels.c
+++ b/channels.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: channels.c,v 1.377 2017/12/05 01:30:19 djm Exp $ */
+/* $OpenBSD: channels.c,v 1.378 2018/01/23 05:27:21 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -1582,13 +1582,8 @@ channel_post_x11_listener(struct ssh *ssh, Channel *c,
             SSH_CHANNEL_OPENING, newsock, newsock, -1,
             c->local_window_max, c->local_maxpacket, 0, buf, 1);
         open_preamble(ssh, __func__, nc, "x11");
-        if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0) {
-                fatal("%s: channel %i: reply %s", __func__,
-                    c->self, ssh_err(r));
-        }
-        if ((datafellows & SSH_BUG_X11FWD) != 0)
-                debug2("channel %d: ssh2 x11 bug compat mode", nc->self);
-        else if ((r = sshpkt_put_u32(ssh, remote_port)) != 0) {
+        if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 ||
+            (r = sshpkt_put_u32(ssh, remote_port)) != 0) {
                 fatal("%s: channel %i: reply %s", __func__,
                     c->self, ssh_err(r));
         }
@@ -1824,15 +1819,13 @@ channel_post_connecting(struct ssh *ssh, Channel *c,
                         if ((r = sshpkt_start(ssh,
                             SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 ||
                             (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
-                            (r = sshpkt_put_u32(ssh, SSH2_OPEN_CONNECT_FAILED))
-                            != 0)
-                                fatal("%s: channel %i: failure: %s", __func__,
-                                    c->self, ssh_err(r));
-                        if ((datafellows & SSH_BUG_OPENFAILURE) == 0 &&
-                            ((r = sshpkt_put_cstring(ssh, strerror(err))) != 0 ||
-                            (r = sshpkt_put_cstring(ssh, "")) != 0))
+                            (r = sshpkt_put_u32(ssh,
+                            SSH2_OPEN_CONNECT_FAILED)) != 0 ||
+                            (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 ||
+                            (r = sshpkt_put_cstring(ssh, "")) != 0) {
                                 fatal("%s: channel %i: failure: %s", __func__,
                                     c->self, ssh_err(r));
+                        }
                         if ((r = sshpkt_send(ssh)) != 0)
                                 fatal("%s: channel %i: %s", __func__, c->self,
                                     ssh_err(r));
@@ -3110,13 +3103,11 @@ channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh)
                 error("%s: reason: %s", __func__, ssh_err(r));
                 packet_disconnect("Invalid open failure message");
         }
-        if ((datafellows & SSH_BUG_OPENFAILURE) == 0) {
-                /* skip language */
-                if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 ||
-                    (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0) {
-                        error("%s: message/lang: %s", __func__, ssh_err(r));
-                        packet_disconnect("Invalid open failure message");
-                }
+        /* skip language */
+        if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 ||
+            (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0) {
+                error("%s: message/lang: %s", __func__, ssh_err(r));
+                packet_disconnect("Invalid open failure message");
         }
         ssh_packet_check_eom(ssh);
         logit("channel %d: open failed: %s%s%s", c->self,
@@ -3664,15 +3655,9 @@ static const char *
 channel_rfwd_bind_host(const char *listen_host)
 {
         if (listen_host == NULL) {
-                if (datafellows & SSH_BUG_RFWD_ADDR)
-                        return "127.0.0.1";
-                else
-                        return "localhost";
+                return "localhost";
         } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) {
-                if (datafellows & SSH_BUG_RFWD_ADDR)
-                        return "0.0.0.0";
-                else
-                        return "";
+                return "";
         } else
                 return listen_host;
 }
diff --git a/clientloop.c b/clientloop.c
index c187ae570..ed9bebdfa 100644
--- a/clientloop.c
+++ b/clientloop.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: clientloop.c,v 1.309 2017/12/18 23:16:23 djm Exp $ */
+/* $OpenBSD: clientloop.c,v 1.310 2018/01/23 05:27:21 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -1541,12 +1541,7 @@ client_request_x11(struct ssh *ssh, const char *request_type, int rchan)
                 return NULL;
         }
         originator = packet_get_string(NULL);
-        if (datafellows & SSH_BUG_X11FWD) {
-                debug2("buggy server: x11 request w/o originator_port");
-                originator_port = 0;
-        } else {
-                originator_port = packet_get_int();
-        }
+        originator_port = packet_get_int();
         packet_check_eom();
         /* XXX check permission */
         debug("client_request_x11: request from %s %d", originator,
@@ -1678,10 +1673,8 @@ client_input_channel_open(int type, u_int32_t seq, struct ssh *ssh)
                 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
                 packet_put_int(rchan);
                 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
-                if (!(datafellows & SSH_BUG_OPENFAILURE)) {
-                        packet_put_cstring("open failed");
-                        packet_put_cstring("");
-                }
+                packet_put_cstring("open failed");
+                packet_put_cstring("");
                 packet_send();
         }
         free(ctype);
diff --git a/compat.c b/compat.c
index d82135e2b..89b302cca 100644
--- a/compat.c
+++ b/compat.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: compat.c,v 1.104 2017/07/25 09:22:25 dtucker Exp $ */
+/* $OpenBSD: compat.c,v 1.105 2018/01/23 05:27:21 djm Exp $ */
 /*
  * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl.  All rights reserved.
  *
@@ -50,83 +50,20 @@ compat_datafellows(const char *version)
                 char    *pat;
                 int     bugs;
         } check[] = {
-                { "OpenSSH-2.0*,"
-                  "OpenSSH-2.1*,"
-                  "OpenSSH_2.1*,"
-                  "OpenSSH_2.2*",       SSH_OLD_SESSIONID|SSH_BUG_BANNER|
-                                        SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
-                                        SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
-                { "OpenSSH_2.3.0*",     SSH_BUG_BANNER|SSH_BUG_BIGENDIANAES|
-                                        SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
-                                        SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
-                { "OpenSSH_2.3.*",      SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
-                                        SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
-                                        SSH_OLD_FORWARD_ADDR},
-                { "OpenSSH_2.5.0p1*,"
-                  "OpenSSH_2.5.1p1*",
-                                        SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
-                                        SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
-                                        SSH_OLD_FORWARD_ADDR},
-                { "OpenSSH_2.5.0*,"
-                  "OpenSSH_2.5.1*,"
-                  "OpenSSH_2.5.2*",     SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
-                                        SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
-                { "OpenSSH_2.5.3*",     SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
-                                        SSH_OLD_FORWARD_ADDR},
                 { "OpenSSH_2.*,"
                   "OpenSSH_3.0*,"
                   "OpenSSH_3.1*",       SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
                 { "OpenSSH_3.*",        SSH_OLD_FORWARD_ADDR },
                 { "Sun_SSH_1.0*",       SSH_BUG_NOREKEY|SSH_BUG_EXTEOF},
-                { "OpenSSH_4*",         0 },
+                { "OpenSSH_2*,"
+                  "OpenSSH_3*,"
+                  "OpenSSH_4*",         0 },
                 { "OpenSSH_5*",         SSH_NEW_OPENSSH|SSH_BUG_DYNAMIC_RPORT},
                 { "OpenSSH_6.6.1*",     SSH_NEW_OPENSSH},
                 { "OpenSSH_6.5*,"
                   "OpenSSH_6.6*",       SSH_NEW_OPENSSH|SSH_BUG_CURVE25519PAD},
                 { "OpenSSH*",           SSH_NEW_OPENSSH },
                 { "*MindTerm*",         0 },
-                { "2.1.0*",             SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
-                                        SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
-                                        SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE|
-                                        SSH_BUG_FIRSTKEX },
-                { "2.1 *",              SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
-                                        SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
-                                        SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE|
-                                        SSH_BUG_FIRSTKEX },
-                { "2.0.13*,"
-                  "2.0.14*,"
-                  "2.0.15*,"
-                  "2.0.16*,"
-                  "2.0.17*,"
-                  "2.0.18*,"
-                  "2.0.19*",            SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
-                                        SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
-                                        SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
-                                        SSH_BUG_PKOK|SSH_BUG_RSASIGMD5|
-                                        SSH_BUG_HBSERVICE|SSH_BUG_OPENFAILURE|
-                                        SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX },
-                { "2.0.11*,"
-                  "2.0.12*",            SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
-                                        SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
-                                        SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
-                                        SSH_BUG_PKAUTH|SSH_BUG_PKOK|
-                                        SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
-                                        SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX },
-                { "2.0.*",              SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
-                                        SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
-                                        SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
-                                        SSH_BUG_PKAUTH|SSH_BUG_PKOK|
-                                        SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
-                                        SSH_BUG_DERIVEKEY|SSH_BUG_DUMMYCHAN|
-                                        SSH_BUG_FIRSTKEX },
-                { "2.2.0*,"
-                  "2.3.0*",             SSH_BUG_HMAC|SSH_BUG_DEBUG|
-                                        SSH_BUG_RSASIGMD5|SSH_BUG_FIRSTKEX },
-                { "2.3.*",              SSH_BUG_DEBUG|SSH_BUG_RSASIGMD5|
-                                        SSH_BUG_FIRSTKEX },
-                { "2.4",                SSH_OLD_SESSIONID },    /* Van Dyke */
-                { "2.*",                SSH_BUG_DEBUG|SSH_BUG_FIRSTKEX|
-                                        SSH_BUG_RFWD_ADDR },
                 { "3.0.*",              SSH_BUG_DEBUG },
                 { "3.0 SecureCRT*",     SSH_OLD_SESSIONID },
                 { "1.7 SecureFX*",      SSH_OLD_SESSIONID },
diff --git a/compat.h b/compat.h
index 2e7830f1b..246e6ee4c 100644
--- a/compat.h
+++ b/compat.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: compat.h,v 1.49 2017/04/30 23:13:25 djm Exp $ */
+/* $OpenBSD: compat.h,v 1.50 2018/01/23 05:27:21 djm Exp $ */
 
 /*
  * Copyright (c) 1999, 2000, 2001 Markus Friedl.  All rights reserved.
@@ -32,31 +32,31 @@
 #define SSH_PROTO_1_PREFERRED   0x02
 #define SSH_PROTO_2             0x04
 
-#define SSH_BUG_SIGBLOB         0x00000001
-#define SSH_BUG_PKSERVICE       0x00000002
-#define SSH_BUG_HMAC            0x00000004
-#define SSH_BUG_X11FWD          0x00000008
+/* #define unused               0x00000001 */
+/* #define unused               0x00000002 */
+/* #define unused               0x00000004 */
+/* #define unused               0x00000008 */
 #define SSH_OLD_SESSIONID       0x00000010
-#define SSH_BUG_PKAUTH          0x00000020
+/* #define unused               0x00000020 */
 #define SSH_BUG_DEBUG           0x00000040
-#define SSH_BUG_BANNER          0x00000080
+/* #define unused               0x00000080 */
 #define SSH_BUG_IGNOREMSG       0x00000100
-#define SSH_BUG_PKOK            0x00000200
+/* #define unused               0x00000200 */
 #define SSH_BUG_PASSWORDPAD     0x00000400
 #define SSH_BUG_SCANNER         0x00000800
 #define SSH_BUG_BIGENDIANAES    0x00001000
 #define SSH_BUG_RSASIGMD5       0x00002000
 #define SSH_OLD_DHGEX           0x00004000
 #define SSH_BUG_NOREKEY         0x00008000
-#define SSH_BUG_HBSERVICE       0x00010000
-#define SSH_BUG_OPENFAILURE     0x00020000
-#define SSH_BUG_DERIVEKEY       0x00040000
-#define SSH_BUG_DUMMYCHAN       0x00100000
+/* #define unused               0x00010000 */
+/* #define unused               0x00020000 */
+/* #define unused               0x00040000 */
+/* #define unused               0x00100000 */
 #define SSH_BUG_EXTEOF          0x00200000
 #define SSH_BUG_PROBE           0x00400000
-#define SSH_BUG_FIRSTKEX        0x00800000
+/* #define unused               0x00800000 */
 #define SSH_OLD_FORWARD_ADDR    0x01000000
-#define SSH_BUG_RFWD_ADDR       0x02000000
+/* #define unused               0x02000000 */
 #define SSH_NEW_OPENSSH         0x04000000
 #define SSH_BUG_DYNAMIC_RPORT   0x08000000
 #define SSH_BUG_CURVE25519PAD   0x10000000
diff --git a/kex.c b/kex.c
index d5d5a9dae..83c6199f3 100644
--- a/kex.c
+++ b/kex.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kex.c,v 1.134 2017/06/13 12:13:59 djm Exp $ */
+/* $OpenBSD: kex.c,v 1.135 2018/01/23 05:27:21 djm Exp $ */
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  *
@@ -675,9 +675,6 @@ choose_mac(struct ssh *ssh, struct sshmac *mac, char *client, char *server)
                 free(name);
                 return SSH_ERR_INTERNAL_ERROR;
         }
-        /* truncate the key */
-        if (ssh->compat & SSH_BUG_HMAC)
-                mac->key_len = 16;
         mac->name = name;
         mac->key = NULL;
         mac->enabled = 0;
@@ -866,8 +863,7 @@ kex_choose_conf(struct ssh *ssh)
         kex->dh_need = dh_need;
 
         /* ignore the next message if the proposals do not match */
-        if (first_kex_follows && !proposals_match(my, peer) &&
-            !(ssh->compat & SSH_BUG_FIRSTKEX))
+        if (first_kex_follows && !proposals_match(my, peer))
                 ssh->dispatch_skip_packets = 1;
         r = 0;
  out:
diff --git a/monitor.c b/monitor.c
index b0227eee1..89c8c958a 100644
--- a/monitor.c
+++ b/monitor.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: monitor.c,v 1.177 2017/12/21 00:00:28 djm Exp $ */
+/* $OpenBSD: monitor.c,v 1.178 2018/01/23 05:27:21 djm Exp $ */
 /*
  * Copyright 2002 Niels Provos <provos@citi.umich.edu>
  * Copyright 2002 Markus Friedl <markus@openbsd.org>
@@ -1255,18 +1255,13 @@ monitor_valid_userblob(u_char *data, u_int datalen)
         free(userstyle);
         free(cp);
         buffer_skip_string(&b);
-        if (datafellows & SSH_BUG_PKAUTH) {
-                if (!buffer_get_char(&b))
-                        fail++;
-        } else {
-                cp = buffer_get_cstring(&b, NULL);
-                if (strcmp("publickey", cp) != 0)
-                        fail++;
-                free(cp);
-                if (!buffer_get_char(&b))
-                        fail++;
-                buffer_skip_string(&b);
-        }
+        cp = buffer_get_cstring(&b, NULL);
+        if (strcmp("publickey", cp) != 0)
+                fail++;
+        free(cp);
+        if (!buffer_get_char(&b))
+                fail++;
+        buffer_skip_string(&b);
         buffer_skip_string(&b);
         if (buffer_len(&b) != 0)
                 fail++;
diff --git a/serverloop.c b/serverloop.c
index 615921c38..feaf35c1a 100644
--- a/serverloop.c
+++ b/serverloop.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: serverloop.c,v 1.202 2017/12/18 23:16:24 djm Exp $ */
+/* $OpenBSD: serverloop.c,v 1.203 2018/01/23 05:27:21 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -655,10 +655,8 @@ server_input_channel_open(int type, u_int32_t seq, struct ssh *ssh)
                 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
                 packet_put_int(rchan);
                 packet_put_int(reason);
-                if (!(datafellows & SSH_BUG_OPENFAILURE)) {
-                        packet_put_cstring(errmsg ? errmsg : "open failed");
-                        packet_put_cstring("");
-                }
+                packet_put_cstring(errmsg ? errmsg : "open failed");
+                packet_put_cstring("");
                 packet_send();
         }
         free(ctype);
diff --git a/ssh-agent.c b/ssh-agent.c
index 8cb00f620..39888a72c 100644
--- a/ssh-agent.c
+++ b/ssh-agent.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-agent.c,v 1.226 2017/11/15 02:10:16 djm Exp $ */
+/* $OpenBSD: ssh-agent.c,v 1.227 2018/01/23 05:27:21 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -292,8 +292,6 @@ process_sign_request2(SocketEntry *e)
                 goto send;
         }
 
-        if (flags & SSH_AGENT_OLD_SIGNATURE)
-                compat = SSH_BUG_SIGBLOB;
         if ((id = lookup_identity(key)) == NULL) {
                 verbose("%s: %s key not found", __func__, sshkey_type(key));
                 goto send;
diff --git a/ssh-dss.c b/ssh-dss.c
index 7af59fa6e..cda498a87 100644
--- a/ssh-dss.c
+++ b/ssh-dss.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-dss.c,v 1.35 2016/04/21 06:08:02 djm Exp $ */
+/* $OpenBSD: ssh-dss.c,v 1.36 2018/01/23 05:27:21 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -86,38 +86,25 @@ ssh_dss_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
         BN_bn2bin(sig->r, sigblob + SIGBLOB_LEN - INTBLOB_LEN - rlen);
         BN_bn2bin(sig->s, sigblob + SIGBLOB_LEN - slen);
 
-        if (compat & SSH_BUG_SIGBLOB) {
-                if (sigp != NULL) {
-                        if ((*sigp = malloc(SIGBLOB_LEN)) == NULL) {
-                                ret = SSH_ERR_ALLOC_FAIL;
-                                goto out;
-                        }
-                        memcpy(*sigp, sigblob, SIGBLOB_LEN);
-                }
-                if (lenp != NULL)
-                        *lenp = SIGBLOB_LEN;
-                ret = 0;
-        } else {
-                /* ietf-drafts */
-                if ((b = sshbuf_new()) == NULL) {
+        if ((b = sshbuf_new()) == NULL) {
+                ret = SSH_ERR_ALLOC_FAIL;
+                goto out;
+        }
+        if ((ret = sshbuf_put_cstring(b, "ssh-dss")) != 0 ||
+            (ret = sshbuf_put_string(b, sigblob, SIGBLOB_LEN)) != 0)
+                goto out;
+
+        len = sshbuf_len(b);
+        if (sigp != NULL) {
+                if ((*sigp = malloc(len)) == NULL) {
                         ret = SSH_ERR_ALLOC_FAIL;
                         goto out;
                 }
-                if ((ret = sshbuf_put_cstring(b, "ssh-dss")) != 0 ||
-                    (ret = sshbuf_put_string(b, sigblob, SIGBLOB_LEN)) != 0)
-                        goto out;
-                len = sshbuf_len(b);
-                if (sigp != NULL) {
-                        if ((*sigp = malloc(len)) == NULL) {
-                                ret = SSH_ERR_ALLOC_FAIL;
-                                goto out;
-                        }
-                        memcpy(*sigp, sshbuf_ptr(b), len);
-                }
-                if (lenp != NULL)
-                        *lenp = len;
-                ret = 0;
+                memcpy(*sigp, sshbuf_ptr(b), len);
         }
+        if (lenp != NULL)
+                *lenp = len;
+        ret = 0;
  out:
         explicit_bzero(digest, sizeof(digest));
         if (sig != NULL)
@@ -146,28 +133,20 @@ ssh_dss_verify(const struct sshkey *key,
                 return SSH_ERR_INTERNAL_ERROR;
 
         /* fetch signature */
-        if (compat & SSH_BUG_SIGBLOB) {
-                if ((sigblob = malloc(signaturelen)) == NULL)
-                        return SSH_ERR_ALLOC_FAIL;
-                memcpy(sigblob, signature, signaturelen);
-                len = signaturelen;
-        } else {
-                /* ietf-drafts */
-                if ((b = sshbuf_from(signature, signaturelen)) == NULL)
-                        return SSH_ERR_ALLOC_FAIL;
-                if (sshbuf_get_cstring(b, &ktype, NULL) != 0 ||
-                    sshbuf_get_string(b, &sigblob, &len) != 0) {
-                        ret = SSH_ERR_INVALID_FORMAT;
-                        goto out;
-                }
-                if (strcmp("ssh-dss", ktype) != 0) {
-                        ret = SSH_ERR_KEY_TYPE_MISMATCH;
-                        goto out;
-                }
-                if (sshbuf_len(b) != 0) {
-                        ret = SSH_ERR_UNEXPECTED_TRAILING_DATA;
-                        goto out;
-                }
+        if ((b = sshbuf_from(signature, signaturelen)) == NULL)
+                return SSH_ERR_ALLOC_FAIL;
+        if (sshbuf_get_cstring(b, &ktype, NULL) != 0 ||
+            sshbuf_get_string(b, &sigblob, &len) != 0) {
+                ret = SSH_ERR_INVALID_FORMAT;
+                goto out;
+        }
+        if (strcmp("ssh-dss", ktype) != 0) {
+                ret = SSH_ERR_KEY_TYPE_MISMATCH;
+                goto out;
+        }
+        if (sshbuf_len(b) != 0) {
+                ret = SSH_ERR_UNEXPECTED_TRAILING_DATA;
+                goto out;
         }
 
         if (len != SIGBLOB_LEN) {
diff --git a/ssh.c b/ssh.c
index ac85b2bb5..af4597f88 100644
--- a/ssh.c
+++ b/ssh.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh.c,v 1.470 2018/01/23 05:06:25 djm Exp $ */
+/* $OpenBSD: ssh.c,v 1.471 2018/01/23 05:27:21 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -1931,7 +1931,7 @@ ssh_session2(struct ssh *ssh, struct passwd *pw)
         if (options.control_persist && muxserver_sock == -1)
                 ssh_init_stdio_forwarding(ssh);
 
-        if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
+        if (!no_shell_flag)
                 id = ssh_session2_open(ssh);
         else {
                 packet_set_interactive(
diff --git a/sshconnect.c b/sshconnect.c
index c25e192c8..0e195a31d 100644
--- a/sshconnect.c
+++ b/sshconnect.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshconnect.c,v 1.290 2018/01/23 05:17:04 djm Exp $ */
+/* $OpenBSD: sshconnect.c,v 1.291 2018/01/23 05:27:21 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -617,9 +617,6 @@ ssh_exchange_identification(int timeout_ms)
         if (mismatch)
                 fatal("Protocol major versions differ: %d vs. %d",
                     PROTOCOL_MAJOR_2, remote_major);
-        if ((datafellows & SSH_BUG_DERIVEKEY) != 0)
-                fatal("Server version \"%.100s\" uses unsafe key agreement; "
-                    "refusing connection", remote_version);
         if ((datafellows & SSH_BUG_RSASIGMD5) != 0)
                 logit("Server version \"%.100s\" uses unsafe RSA signature "
                     "scheme; disabling use of RSA keys", remote_version);
diff --git a/sshconnect2.c b/sshconnect2.c
index be9397e48..870c3d270 100644
--- a/sshconnect2.c
+++ b/sshconnect2.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshconnect2.c,v 1.266 2017/08/27 00:38:41 dtucker Exp $ */
+/* $OpenBSD: sshconnect2.c,v 1.267 2018/01/23 05:27:21 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  * Copyright (c) 2008 Damien Miller.  All rights reserved.
@@ -578,7 +578,6 @@ input_userauth_pk_ok(int type, u_int32_t seq, struct ssh *ssh)
         Authctxt *authctxt = ssh->authctxt;
         struct sshkey *key = NULL;
         Identity *id = NULL;
-        Buffer b;
         int pktype, sent = 0;
         u_int alen, blen;
         char *pkalg, *fp;
@@ -586,18 +585,9 @@ input_userauth_pk_ok(int type, u_int32_t seq, struct ssh *ssh)
 
         if (authctxt == NULL)
                 fatal("input_userauth_pk_ok: no authentication context");
-        if (datafellows & SSH_BUG_PKOK) {
-                /* this is similar to SSH_BUG_PKAUTH */
-                debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
-                pkblob = packet_get_string(&blen);
-                buffer_init(&b);
-                buffer_append(&b, pkblob, blen);
-                pkalg = buffer_get_string(&b, &alen);
-                buffer_free(&b);
-        } else {
-                pkalg = packet_get_string(&alen);
-                pkblob = packet_get_string(&blen);
-        }
+
+        pkalg = packet_get_string(&alen);
+        pkblob = packet_get_string(&blen);
         packet_check_eom();
 
         debug("Server accepts key: pkalg %s blen %u", pkalg, blen);
@@ -1100,17 +1090,10 @@ sign_and_send_pubkey(Authctxt *authctxt, Identity *id)
         }
         buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
         buffer_put_cstring(&b, authctxt->server_user);
-        buffer_put_cstring(&b,
-            datafellows & SSH_BUG_PKSERVICE ?
-            "ssh-userauth" :
-            authctxt->service);
-        if (datafellows & SSH_BUG_PKAUTH) {
-                buffer_put_char(&b, have_sig);
-        } else {
-                buffer_put_cstring(&b, authctxt->method->name);
-                buffer_put_char(&b, have_sig);
-                buffer_put_cstring(&b, key_sign_encode(id->key));
-        }
+        buffer_put_cstring(&b, authctxt->service);
+        buffer_put_cstring(&b, authctxt->method->name);
+        buffer_put_char(&b, have_sig);
+        buffer_put_cstring(&b, key_sign_encode(id->key));
         buffer_put_string(&b, blob, bloblen);
 
         /*
@@ -1170,19 +1153,6 @@ sign_and_send_pubkey(Authctxt *authctxt, Identity *id)
 #ifdef DEBUG_PK
         buffer_dump(&b);
 #endif
-        if (datafellows & SSH_BUG_PKSERVICE) {
-                buffer_clear(&b);
-                buffer_append(&b, session_id2, session_id2_len);
-                skip = session_id2_len;
-                buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
-                buffer_put_cstring(&b, authctxt->server_user);
-                buffer_put_cstring(&b, authctxt->service);
-                buffer_put_cstring(&b, authctxt->method->name);
-                buffer_put_char(&b, have_sig);
-                if (!(datafellows & SSH_BUG_PKAUTH))
-                        buffer_put_cstring(&b, key_ssh_name(id->key));
-                buffer_put_string(&b, blob, bloblen);
-        }
         free(blob);
 
         /* append signature */
@@ -1224,8 +1194,7 @@ send_pubkey_test(Authctxt *authctxt, Identity *id)
         packet_put_cstring(authctxt->service);
         packet_put_cstring(authctxt->method->name);
         packet_put_char(have_sig);
-        if (!(datafellows & SSH_BUG_PKAUTH))
-                packet_put_cstring(key_sign_encode(id->key));
+        packet_put_cstring(key_sign_encode(id->key));
         packet_put_string(blob, bloblen);
         free(blob);
         packet_send();
@@ -1741,7 +1710,6 @@ userauth_hostbased(Authctxt *authctxt)
         struct ssh *ssh = active_state;
         struct sshkey *private = NULL;
         struct sshbuf *b = NULL;
-        const char *service;
         u_char *sig = NULL, *keyblob = NULL;
         char *fp = NULL, *chost = NULL, *lname = NULL;
         size_t siglen = 0, keylen = 0;
@@ -1812,9 +1780,6 @@ userauth_hostbased(Authctxt *authctxt)
         xasprintf(&chost, "%s.", lname);
         debug2("%s: chost %s", __func__, chost);
 
-        service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
-            authctxt->service;
-
         /* construct data */
         if ((b = sshbuf_new()) == NULL) {
                 error("%s: sshbuf_new failed", __func__);
@@ -1827,7 +1792,7 @@ userauth_hostbased(Authctxt *authctxt)
         if ((r = sshbuf_put_string(b, session_id2, session_id2_len)) != 0 ||
             (r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
             (r = sshbuf_put_cstring(b, authctxt->server_user)) != 0 ||
-            (r = sshbuf_put_cstring(b, service)) != 0 ||
+            (r = sshbuf_put_cstring(b, authctxt->service)) != 0 ||
             (r = sshbuf_put_cstring(b, authctxt->method->name)) != 0 ||
             (r = sshbuf_put_cstring(b, key_ssh_name(private))) != 0 ||
             (r = sshbuf_put_string(b, keyblob, keylen)) != 0 ||
diff --git a/sshd.c b/sshd.c
index 6133135db..e7e3c99b4 100644
--- a/sshd.c
+++ b/sshd.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshd.c,v 1.501 2018/01/23 05:12:12 djm Exp $ */
+/* $OpenBSD: sshd.c,v 1.502 2018/01/23 05:27:21 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -446,10 +446,6 @@ sshd_exchange_identification(struct ssh *ssh, int sock_in, int sock_out)
                 logit("Client version \"%.100s\" uses unsafe RSA signature "
                     "scheme; disabling use of RSA keys", remote_version);
         }
-        if ((ssh->compat & SSH_BUG_DERIVEKEY) != 0) {
-                fatal("Client version \"%.100s\" uses unsafe key agreement; "
-                    "refusing connection", remote_version);
-        }
 
         chop(server_version_string);
         debug("Local version string %.200s", server_version_string);