- OpenBSD CVS updates:

   - [channels.c]
     repair x11-fwd
   - [sshconnect.c]
     fix passwd prompt for ssh2, less debugging output.
   - [clientloop.c compat.c dsa.c kex.c sshd.c]
     less debugging output
   - [kex.c kex.h sshconnect.c sshd.c]
     check for reasonable public DH values
   - [README.openssh2 cipher.c cipher.h compat.c compat.h readconf.c]
     [readconf.h servconf.c servconf.h ssh.c ssh.h sshconnect.c sshd.c]
     add Cipher and Protocol options to ssh/sshd, e.g.:
     ssh -o 'Protocol 1,2' if you prefer proto 1, ssh -o 'Ciphers
     arcfour,3des-cbc'
   - [sshd.c]
     print 1.99 only if server supports both

1 files changed, 57 insertions, 34 deletions

diff --git a/sshconnect.c b/sshconnect.c
index 2f9496090..167b8e63a 100644
--- a/sshconnect.c
+++ b/sshconnect.c
@@ -10,7 +10,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: sshconnect.c,v 1.61 2000/04/04 21:37:27 markus Exp $");
+RCSID("$OpenBSD: sshconnect.c,v 1.65 2000/04/12 07:56:16 markus Exp $");
 
 #ifdef HAVE_OPENSSL
 #include <openssl/bn.h>
@@ -993,7 +993,7 @@ void
 ssh_exchange_identification()
 {
         char buf[256], remote_version[256];     /* must be same size! */
-        int remote_major, remote_minor, i;
+        int remote_major, remote_minor, i, mismatch;
         int connection_in = packet_get_connection_in();
         int connection_out = packet_get_connection_out();
 
@@ -1027,39 +1027,51 @@ ssh_exchange_identification()
         debug("Remote protocol version %d.%d, remote software version %.100s",
               remote_major, remote_minor, remote_version);
 
-/*** XXX option for disabling 2.0 or 1.5 */
         compat_datafellows(remote_version);
-
-        /* Check if the remote protocol version is too old. */
-        if (remote_major == 1 && remote_minor < 3)
-                fatal("Remote machine has too old SSH software version.");
-
-        /* We speak 1.3, too. */
-        if (remote_major == 1 && remote_minor == 3) {
-                enable_compat13();
-                if (options.forward_agent) {
-                        log("Agent forwarding disabled for protocol 1.3");
-                        options.forward_agent = 0;
+        mismatch = 0;
+
+        switch(remote_major) {
+        case 1:
+                if (remote_minor == 99 &&
+                    (options.protocol & SSH_PROTO_2) &&
+                    !(options.protocol & SSH_PROTO_1_PREFERRED)) {
+                        enable_compat20();
+                        break;
                 }
+                if (!(options.protocol & SSH_PROTO_1)) {
+                        mismatch = 1;
+                        break;
+                }
+                if (remote_minor < 3) {
+                        fatal("Remote machine has too old SSH software version.");
+                } else if (remote_minor == 3) {
+                        /* We speak 1.3, too. */
+                        enable_compat13();
+                        if (options.forward_agent) {
+                                log("Agent forwarding disabled for protocol 1.3");
+                                options.forward_agent = 0;
+                        }
+                }
+                break;
+        case 2:
+                if (options.protocol & SSH_PROTO_2) {
+                        enable_compat20();
+                        break;
+                }
+                /* FALLTHROUGH */
+        default: 
+                mismatch = 1;
+                break;
         }
-        if ((remote_major == 2 && remote_minor == 0) ||
-            (remote_major == 1 && remote_minor == 99)) {
-                enable_compat20();
-        }
-#if 0
-        /*
-         * Removed for now, to permit compatibility with latter versions. The
-         * server will reject our version and disconnect if it doesn't
-         * support it.
-         */
-        if (remote_major != PROTOCOL_MAJOR)
+        if (mismatch)
                 fatal("Protocol major versions differ: %d vs. %d",
-                      PROTOCOL_MAJOR, remote_major);
-#endif
+                    (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
+                    remote_major);
+
         /* Send our own protocol version identification. */
         snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
-            compat20 ? 2 : PROTOCOL_MAJOR,
-            compat20 ? 0 : PROTOCOL_MINOR,
+            compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
+            compat20 ? PROTOCOL_MINOR_2 : PROTOCOL_MINOR_1,
             SSH_VERSION);
         if (atomicio(write, connection_out, buf, strlen(buf)) != strlen(buf))
                 fatal("write: %.100s", strerror(errno));
@@ -1350,11 +1362,15 @@ ssh_kex2(char *host, struct sockaddr *hostaddr)
 /* KEXINIT */
 
         debug("Sending KEX init.");
-        if (options.cipher == SSH_CIPHER_ARCFOUR ||
+        if (options.ciphers != NULL) {
+                myproposal[PROPOSAL_ENC_ALGS_CTOS] = 
+                myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
+        } else if (
+            options.cipher == SSH_CIPHER_ARCFOUR ||
             options.cipher == SSH_CIPHER_3DES_CBC ||
             options.cipher == SSH_CIPHER_CAST128_CBC ||
             options.cipher == SSH_CIPHER_BLOWFISH_CBC) {
-                myproposal[PROPOSAL_ENC_ALGS_CTOS] = cipher_name(options.cipher);
+                myproposal[PROPOSAL_ENC_ALGS_CTOS] =
                 myproposal[PROPOSAL_ENC_ALGS_STOC] = cipher_name(options.cipher);
         }
         if (options.compression) {
@@ -1404,7 +1420,7 @@ ssh_kex2(char *host, struct sockaddr *hostaddr)
         debug("Sending SSH2_MSG_KEXDH_INIT.");
 
         /* generate and send 'e', client DH public key */
-        dh = new_dh_group1();
+        dh = dh_new_group1();
         packet_start(SSH2_MSG_KEXDH_INIT);
         packet_put_bignum2(dh->pub_key);
         packet_send();
@@ -1451,6 +1467,9 @@ ssh_kex2(char *host, struct sockaddr *hostaddr)
         /* signed H */
         signature = packet_get_string(&slen);
 
+        if (!dh_pub_is_valid(dh, dh_server_pub))
+                packet_disconnect("bad server public DH value");
+
         klen = DH_size(dh);
         kbuf = xmalloc(klen);
         kout = DH_compute_key(kbuf, dh_server_pub, dh);
@@ -1507,12 +1526,13 @@ ssh_kex2(char *host, struct sockaddr *hostaddr)
         packet_write_wait();
         debug("done: send SSH2_MSG_NEWKEYS.");
 
+#ifdef DEBUG_KEXDH
         /* send 1st encrypted/maced/compressed message */
         packet_start(SSH2_MSG_IGNORE);
         packet_put_cstring("markus");
         packet_send();
         packet_write_wait();
-
+#endif
         debug("done: KEX2.");
 }
 /*
@@ -1527,6 +1547,7 @@ ssh_userauth2(int host_key_valid, RSA *own_host_key,
         unsigned int dlen;
         int partial;
         struct passwd *pw;
+        char prompt[80];
         char *server_user, *local_user;
         char *auths;
         char *password;
@@ -1578,7 +1599,9 @@ ssh_userauth2(int host_key_valid, RSA *own_host_key,
                         fatal("passwd auth not supported: %s", auths);
                 xfree(auths);
                 /* try passwd */
-                password = read_passphrase("password: ", 0);
+                snprintf(prompt, sizeof(prompt), "%.30s@%.40s's password: ",
+                    server_user, host);
+                password = read_passphrase(prompt, 0);
                 packet_start(SSH2_MSG_USERAUTH_REQUEST);
                 packet_put_cstring(server_user);
                 packet_put_cstring(service);