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 9f4e576..4c8d5da 100644 (file)
--- 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 322c29a..8c5d631 100644 (file)
--- 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 6a17227..4f3e247 100644 (file)
--- 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;