From: djm <djm@openbsd.org>
Date: Mon, 13 Apr 2015 02:04:08 +0000 (+0000)
Subject: deprecate ancient, pre-RFC4419 and undocumented
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=2abcec04983fc99b9d0c555b0988b3c31d5cebe3;p=openbsd

deprecate ancient, pre-RFC4419 and undocumented
SSH2_MSG_KEX_DH_GEX_REQUEST_OLD message;
ok markus@ deraadt@ "seems reasonable" dtucker@
---

diff --git a/usr.bin/ssh/compat.c b/usr.bin/ssh/compat.c
index 9f4e576a8de..4c8d5dafcce 100644
--- a/usr.bin/ssh/compat.c
+++ b/usr.bin/ssh/compat.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: compat.c,v 1.89 2015/04/10 05:16:50 dtucker Exp $ */
+/* $OpenBSD: compat.c,v 1.90 2015/04/13 02:04:08 djm Exp $ */
 /*
  * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl.  All rights reserved.
  *
@@ -163,6 +163,7 @@ compat_datafellows(const char *version)
 		  "OSU_1.5alpha3*",	SSH_BUG_PASSWORDPAD },
 		{ "*SSH_Version_Mapper*",
 					SSH_BUG_SCANNER },
+		{ "PuTTY*",		SSH_OLD_DHGEX },
 		{ "Probe-*",
 					SSH_BUG_PROBE },
 		{ "TeraTerm SSH*,"
@@ -282,15 +283,20 @@ compat_pkalg_proposal(char *pkalg_prop)
 }
 
 char *
-compat_kex_proposal(char *kex_prop)
+compat_kex_proposal(char *p)
 {
-	if (!(datafellows & SSH_BUG_CURVE25519PAD))
-		return kex_prop;
-	debug2("%s: original KEX proposal: %s", __func__, kex_prop);
-	kex_prop = filter_proposal(kex_prop, "curve25519-sha256@libssh.org");
-	debug2("%s: compat KEX proposal: %s", __func__, kex_prop);
-	if (*kex_prop == '\0')
+	if ((datafellows & (SSH_BUG_CURVE25519PAD|SSH_OLD_DHGEX)) == 0)
+		return p;
+	debug2("%s: original KEX proposal: %s", __func__, p);
+	if ((datafellows & SSH_BUG_CURVE25519PAD) != 0)
+		p = filter_proposal(p, "curve25519-sha256@libssh.org");
+	if ((datafellows & SSH_OLD_DHGEX) != 0) {
+		p = filter_proposal(p, "diffie-hellman-group-exchange-sha256");
+		p = filter_proposal(p, "diffie-hellman-group-exchange-sha1");
+	}
+	debug2("%s: compat KEX proposal: %s", __func__, p);
+	if (*p == '\0')
 		fatal("No supported key exchange algorithms found");
-	return kex_prop;
+	return p;
 }
 
diff --git a/usr.bin/ssh/kexgexc.c b/usr.bin/ssh/kexgexc.c
index 322c29a2519..8c5d631a0ab 100644
--- a/usr.bin/ssh/kexgexc.c
+++ b/usr.bin/ssh/kexgexc.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kexgexc.c,v 1.20 2015/01/26 06:10:03 djm Exp $ */
+/* $OpenBSD: kexgexc.c,v 1.21 2015/04/13 02:04:08 djm Exp $ */
 /*
  * Copyright (c) 2000 Niels Provos.  All rights reserved.
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
@@ -60,25 +60,15 @@ kexgex_client(struct ssh *ssh)
 	kex->min = DH_GRP_MIN;
 	kex->max = DH_GRP_MAX;
 	kex->nbits = nbits;
-	if (ssh->compat & SSH_OLD_DHGEX) {
-		/* Old GEX request */
-		if ((r = sshpkt_start(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST_OLD))
-		    != 0 ||
-		    (r = sshpkt_put_u32(ssh, kex->nbits)) != 0 ||
-		    (r = sshpkt_send(ssh)) != 0)
-			goto out;
-		debug("SSH2_MSG_KEX_DH_GEX_REQUEST_OLD(%u) sent", kex->nbits);
-	} else {
-		/* New GEX request */
-		if ((r = sshpkt_start(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST)) != 0 ||
-		    (r = sshpkt_put_u32(ssh, kex->min)) != 0 ||
-		    (r = sshpkt_put_u32(ssh, kex->nbits)) != 0 ||
-		    (r = sshpkt_put_u32(ssh, kex->max)) != 0 ||
-		    (r = sshpkt_send(ssh)) != 0)
-			goto out;
-		debug("SSH2_MSG_KEX_DH_GEX_REQUEST(%u<%u<%u) sent",
-		    kex->min, kex->nbits, kex->max);
-	}
+	/* New GEX request */
+	if ((r = sshpkt_start(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST)) != 0 ||
+	    (r = sshpkt_put_u32(ssh, kex->min)) != 0 ||
+	    (r = sshpkt_put_u32(ssh, kex->nbits)) != 0 ||
+	    (r = sshpkt_put_u32(ssh, kex->max)) != 0 ||
+	    (r = sshpkt_send(ssh)) != 0)
+		goto out;
+	debug("SSH2_MSG_KEX_DH_GEX_REQUEST(%u<%u<%u) sent",
+	    kex->min, kex->nbits, kex->max);
 #ifdef DEBUG_KEXDH
 	fprintf(stderr, "\nmin = %d, nbits = %d, max = %d\n",
 	    kex->min, kex->nbits, kex->max);
diff --git a/usr.bin/ssh/kexgexs.c b/usr.bin/ssh/kexgexs.c
index 6a172270e2d..4f3e247a3bd 100644
--- a/usr.bin/ssh/kexgexs.c
+++ b/usr.bin/ssh/kexgexs.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kexgexs.c,v 1.24 2015/01/26 06:10:03 djm Exp $ */
+/* $OpenBSD: kexgexs.c,v 1.25 2015/04/13 02:04:08 djm Exp $ */
 /*
  * Copyright (c) 2000 Niels Provos.  All rights reserved.
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
@@ -55,8 +55,6 @@ static int input_kex_dh_gex_init(int, u_int32_t, void *);
 int
 kexgex_server(struct ssh *ssh)
 {
-	ssh_dispatch_set(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST_OLD,
-	    &input_kex_dh_gex_request);
 	ssh_dispatch_set(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST,
 	    &input_kex_dh_gex_request);
 	debug("expecting SSH2_MSG_KEX_DH_GEX_REQUEST");
@@ -71,36 +69,19 @@ input_kex_dh_gex_request(int type, u_int32_t seq, void *ctxt)
 	int r;
 	u_int min = 0, max = 0, nbits = 0;
 
-	switch (type) {
-	case SSH2_MSG_KEX_DH_GEX_REQUEST:
-		debug("SSH2_MSG_KEX_DH_GEX_REQUEST received");
-		if ((r = sshpkt_get_u32(ssh, &min)) != 0 ||
-		    (r = sshpkt_get_u32(ssh, &nbits)) != 0 ||
-		    (r = sshpkt_get_u32(ssh, &max)) != 0 ||
-		    (r = sshpkt_get_end(ssh)) != 0)
-			goto out;
-		kex->nbits = nbits;
-		kex->min = min;
-		kex->max = max;
-		min = MAX(DH_GRP_MIN, min);
-		max = MIN(DH_GRP_MAX, max);
-		nbits = MAX(DH_GRP_MIN, nbits);
-		nbits = MIN(DH_GRP_MAX, nbits);
-		break;
-	case SSH2_MSG_KEX_DH_GEX_REQUEST_OLD:
-		debug("SSH2_MSG_KEX_DH_GEX_REQUEST_OLD received");
-		if ((r = sshpkt_get_u32(ssh, &nbits)) != 0 ||
-		    (r = sshpkt_get_end(ssh)) != 0)
-			goto out;
-		kex->nbits = nbits;
-		/* unused for old GEX */
-		kex->min = min = DH_GRP_MIN;
-		kex->max = max = DH_GRP_MAX;
-		break;
-	default:
-		r = SSH_ERR_INVALID_ARGUMENT;
+	debug("SSH2_MSG_KEX_DH_GEX_REQUEST received");
+	if ((r = sshpkt_get_u32(ssh, &min)) != 0 ||
+	    (r = sshpkt_get_u32(ssh, &nbits)) != 0 ||
+	    (r = sshpkt_get_u32(ssh, &max)) != 0 ||
+	    (r = sshpkt_get_end(ssh)) != 0)
 		goto out;
-	}
+	kex->nbits = nbits;
+	kex->min = min;
+	kex->max = max;
+	min = MAX(DH_GRP_MIN, min);
+	max = MIN(DH_GRP_MAX, max);
+	nbits = MAX(DH_GRP_MIN, nbits);
+	nbits = MIN(DH_GRP_MAX, nbits);
 
 	if (kex->max < kex->min || kex->nbits < kex->min ||
 	    kex->max < kex->nbits) {
@@ -126,10 +107,6 @@ input_kex_dh_gex_request(int type, u_int32_t seq, void *ctxt)
 	if ((r = dh_gen_key(kex->dh, kex->we_need * 8)) != 0)
 		goto out;
 
-	/* old KEX does not use min/max in kexgex_hash() */
-	if (type == SSH2_MSG_KEX_DH_GEX_REQUEST_OLD)
-		kex->min = kex->max = -1;
-
 	debug("expecting SSH2_MSG_KEX_DH_GEX_INIT");
 	ssh_dispatch_set(ssh, SSH2_MSG_KEX_DH_GEX_INIT, &input_kex_dh_gex_init);
 	r = 0;