- 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, 51 insertions, 25 deletions

diff --git a/sshd.c b/sshd.c
index 44782e397..266146bf0 100644
--- a/sshd.c
+++ b/sshd.c
@@ -14,7 +14,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: sshd.c,v 1.99 2000/04/07 09:17:39 markus Exp $");
+RCSID("$OpenBSD: sshd.c,v 1.103 2000/04/12 08:11:36 markus Exp $");
 
 #include "xmalloc.h"
 #include "rsa.h"
@@ -77,9 +77,6 @@ int IPv4or6 = AF_INET;
 int IPv4or6 = AF_UNSPEC;
 #endif
 
-/* Flag indicating whether SSH2 is enabled */
-int allow_ssh2 = 0;
-
 /*
  * Debug mode flag.  This can be set on the command line.  If debug
  * mode is enabled, extra debugging output will be sent to the system
@@ -284,16 +281,25 @@ chop(char *s)
 void
 sshd_exchange_identification(int sock_in, int sock_out)
 {
-        int i;
+        int i, mismatch;
         int remote_major, remote_minor;
+        int major, minor;
         char *s;
         char buf[256];                  /* Must not be larger than remote_version. */
         char remote_version[256];       /* Must be at least as big as buf. */
 
-        snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
-                 allow_ssh2 ? 1  : PROTOCOL_MAJOR,
-                 allow_ssh2 ? 99 : PROTOCOL_MINOR,
-                 SSH_VERSION);
+        if ((options.protocol & SSH_PROTO_1) &&
+            (options.protocol & SSH_PROTO_2)) {
+                major = PROTOCOL_MAJOR_1;
+                minor = 99;
+        } else if (options.protocol & SSH_PROTO_2) {
+                major = PROTOCOL_MAJOR_2;
+                minor = PROTOCOL_MINOR_2;
+        } else {
+                major = PROTOCOL_MAJOR_1;
+                minor = PROTOCOL_MINOR_1;
+        }
+        snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION);
         server_version_string = xstrdup(buf);
 
         if (client_version_string == NULL) {
@@ -314,7 +320,6 @@ sshd_exchange_identification(int sock_in, int sock_out)
                                 buf[i] = '\n';
                                 buf[i + 1] = 0;
                                 continue;
-                                //break;
                         }
                         if (buf[i] == '\n') {
                                 /* buf[i] == '\n' */
@@ -345,8 +350,13 @@ sshd_exchange_identification(int sock_in, int sock_out)
 
         compat_datafellows(remote_version);
 
+        mismatch = 0;
         switch(remote_major) {
         case 1:
+                if (!(options.protocol & SSH_PROTO_1)) {
+                        mismatch = 1;
+                        break;
+                }
                 if (remote_minor < 3) {
                         packet_disconnect("Your ssh version is too old and"
                             "is no longer supported.  Please install a newer version.");
@@ -354,27 +364,37 @@ sshd_exchange_identification(int sock_in, int sock_out)
                         /* note that this disables agent-forwarding */
                         enable_compat13();
                 }
-                if (remote_minor != 99)
-                       break;
-                /* FALLTHROUGH */
+                if (remote_minor == 99) {
+                        if (options.protocol & SSH_PROTO_2)
+                                enable_compat20();
+                        else
+                                mismatch = 1;
+                }
+                break;
         case 2:
-                if (allow_ssh2) {
+                if (options.protocol & SSH_PROTO_2) {
                         enable_compat20();
                         break;
                 }
                 /* FALLTHROUGH */
         default: 
+                mismatch = 1;
+                break;
+        }
+        chop(server_version_string);
+        chop(client_version_string);
+        debug("Local version string %.200s", server_version_string);
+
+        if (mismatch) {
                 s = "Protocol major versions differ.\n";
                 (void) atomicio(write, sock_out, s, strlen(s));
                 close(sock_in);
                 close(sock_out);
-                log("Protocol major versions differ for %s: %d vs. %d",
-                    get_remote_ipaddr(), PROTOCOL_MAJOR, remote_major);
+                log("Protocol major versions differ for %s: %.200s vs. %.200s",
+                    get_remote_ipaddr(),
+                    server_version_string, client_version_string);
                 fatal_cleanup();
-                break;
         }
-        chop(server_version_string);
-        chop(client_version_string);
 }
 
 /*
@@ -410,11 +430,8 @@ main(int ac, char **av)
         initialize_server_options(&options);
 
         /* Parse command-line arguments. */
-        while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:diqQ246")) != EOF) {
+        while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:diqQ46")) != EOF) {
                 switch (opt) {
-                case '2':
-                        allow_ssh2 = 1;
-                        break;
                 case '4':
                         IPv4or6 = AF_INET;
                         break;
@@ -593,6 +610,7 @@ main(int ac, char **av)
                 public_key = RSA_new();
                 sensitive_data.private_key = RSA_new();
 
+                /* XXX check options.protocol */
                 log("Generating %d bit RSA key.", options.server_key_bits);
                 rsa_generate_key(sensitive_data.private_key, public_key,
                                  options.server_key_bits);
@@ -1126,6 +1144,11 @@ do_ssh2_kex()
 
 /* KEXINIT */
 
+        if (options.ciphers != NULL) {
+                myproposal[PROPOSAL_ENC_ALGS_CTOS] = 
+                myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
+        }
+
         debug("Sending KEX init.");
 
         for (i = 0; i < PROPOSAL_MAX; i++)
@@ -1185,7 +1208,7 @@ do_ssh2_kex()
 #endif
 
         /* generate DH key */
-        dh = new_dh_group1();                   /* XXX depends on 'kex' */
+        dh = dh_new_group1();                   /* XXX depends on 'kex' */
 
 #ifdef DEBUG_KEXDH
         fprintf(stderr, "\np= ");
@@ -1196,6 +1219,8 @@ do_ssh2_kex()
         bignum_print(dh->pub_key);
         fprintf(stderr, "\n");
 #endif
+        if (!dh_pub_is_valid(dh, dh_client_pub))
+                packet_disconnect("bad client public DH value");
 
         klen = DH_size(dh);
         kbuf = xmalloc(klen);
@@ -1267,11 +1292,12 @@ do_ssh2_kex()
         packet_read_expect(&payload_len, SSH2_MSG_NEWKEYS);
         debug("GOT 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.");
 }