1 files changed, 40 insertions, 43 deletions

diff --git a/sshd.c b/sshd.c
index 371b2a578..03a9ce120 100644
--- a/sshd.c
+++ b/sshd.c
@@ -11,7 +11,7 @@
  */
 
 #include "includes.h"
-RCSID("$Id: sshd.c,v 1.51 2000/01/19 03:36:50 damien Exp $");
+RCSID("$OpenBSD: sshd.c,v 1.79 2000/01/18 13:45:05 markus Exp $");
 
 #include "xmalloc.h"
 #include "rsa.h"
@@ -131,8 +131,8 @@ int received_sighup = 0;
 RSA *public_key;
 
 /* Prototypes for various functions defined later in this file. */
-void do_connection();
-void do_authentication(char *user);
+void do_ssh_kex();
+void do_authentication();
 void do_authloop(struct passwd * pw);
 void do_fake_authloop(char *user);
 void do_authenticated(struct passwd * pw);
@@ -835,11 +835,8 @@ main(int ac, char **av)
                 packet_disconnect("Your ssh version is too old and is no longer supported.  Please install a newer version.");
 
         if (remote_major == 1 && remote_minor == 3) {
+                /* note that this disables agent-forwarding */
                 enable_compat13();
-                if (strcmp(remote_version, "OpenSSH-1.1") != 0) {
-                        debug("Agent forwarding disabled, remote version is not compatible.");
-                        no_agent_forwarding_flag = 1;
-                }
         }
         /*
          * Check that the connection comes from a privileged port.  Rhosts-
@@ -863,8 +860,11 @@ main(int ac, char **av)
 
         packet_set_nonblocking();
 
-        /* Handle the connection. */
-        do_connection();
+        /* perform the key exchange */
+        do_ssh_kex();
+
+        /* authenticate user and start session */
+        do_authentication();
 
 #ifdef KRB4
         /* Cleanup user's ticket cache file. */
@@ -888,20 +888,17 @@ main(int ac, char **av)
 }
 
 /*
- * Process an incoming connection.  Protocol version identifiers have already
- * been exchanged.  This sends server key and performs the key exchange.
- * Server and host keys will no longer be needed after this functions.
+ * SSH1 key exchange
  */
 void
-do_connection()
+do_ssh_kex()
 {
         int i, len;
+        int plen, slen;
         BIGNUM *session_key_int;
         unsigned char session_key[SSH_SESSION_KEY_LENGTH];
-        unsigned char check_bytes[8];
-        char *user;
+        unsigned char cookie[8];
         unsigned int cipher_type, auth_mask, protocol_flags;
-        int plen, slen, ulen;
         u_int32_t rand = 0;
 
         /*
@@ -916,7 +913,7 @@ do_connection()
         for (i = 0; i < 8; i++) {
                 if (i % 4 == 0)
                         rand = arc4random();
-                check_bytes[i] = rand & 0xff;
+                cookie[i] = rand & 0xff;
                 rand >>= 8;
         }
 
@@ -927,7 +924,7 @@ do_connection()
          */
         packet_start(SSH_SMSG_PUBLIC_KEY);
         for (i = 0; i < 8; i++)
-                packet_put_char(check_bytes[i]);
+                packet_put_char(cookie[i]);
 
         /* Store our public server RSA key. */
         packet_put_int(BN_num_bits(public_key->n));
@@ -990,7 +987,7 @@ do_connection()
         /* Get check bytes from the packet.  These must match those we
            sent earlier with the public key packet. */
         for (i = 0; i < 8; i++)
-                if (check_bytes[i] != packet_get_char())
+                if (cookie[i] != packet_get_char())
                         packet_disconnect("IP Spoofing check bytes do not match.");
 
         debug("Encryption type: %.200s", cipher_name(cipher_type));
@@ -1038,10 +1035,15 @@ do_connection()
                                     sensitive_data.private_key);
         }
 
-        compute_session_id(session_id, check_bytes,
+        compute_session_id(session_id, cookie,
                            sensitive_data.host_key->n,
                            sensitive_data.private_key->n);
 
+        /* Destroy the private and public keys.  They will no longer be needed. */
+        RSA_free(public_key);
+        RSA_free(sensitive_data.private_key);
+        RSA_free(sensitive_data.host_key);
+
         /*
          * Extract session key from the decrypted integer.  The key is in the
          * least significant 256 bits of the integer; the first byte of the
@@ -1056,13 +1058,13 @@ do_connection()
         memset(session_key, 0, sizeof(session_key));
         BN_bn2bin(session_key_int, session_key + sizeof(session_key) - len);
 
+        /* Destroy the decrypted integer.  It is no longer needed. */
+        BN_clear_free(session_key_int);
+
         /* Xor the first 16 bytes of the session key with the session id. */
         for (i = 0; i < 16; i++)
                 session_key[i] ^= session_id[i];
 
-        /* Destroy the decrypted integer.  It is no longer needed. */
-        BN_clear_free(session_key_int);
-
         /* Set the session key.  From this on all communications will be encrypted. */
         packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
 
@@ -1075,24 +1077,9 @@ do_connection()
         packet_start(SSH_SMSG_SUCCESS);
         packet_send();
         packet_write_wait();
-
-        /* Get the name of the user that we wish to log in as. */
-        packet_read_expect(&plen, SSH_CMSG_USER);
-
-        /* Get the user name. */
-        user = packet_get_string(&ulen);
-        packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER);
-
-        /* Destroy the private and public keys.  They will no longer be needed. */
-        RSA_free(public_key);
-        RSA_free(sensitive_data.private_key);
-        RSA_free(sensitive_data.host_key);
-
-        setproctitle("%s", user);
-        /* Do the authentication. */
-        do_authentication(user);
 }
 
+
 /*
  * Check if the user is allowed to log in via ssh. If user is listed in
  * DenyUsers or user's primary group is listed in DenyGroups, false will
@@ -1168,13 +1155,23 @@ allowed_user(struct passwd * pw)
 
 /*
  * Performs authentication of an incoming connection.  Session key has already
- * been exchanged and encryption is enabled.  User is the user name to log
- * in as (received from the client).
+ * been exchanged and encryption is enabled.
  */
 void
-do_authentication(char *user)
+do_authentication()
 {
         struct passwd *pw, pwcopy;
+        int plen, ulen;
+        char *user;
+
+        /* Get the name of the user that we wish to log in as. */
+        packet_read_expect(&plen, SSH_CMSG_USER);
+
+        /* Get the user name. */
+        user = packet_get_string(&ulen);
+        packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER);
+
+        setproctitle("%s", user);
 
 #ifdef AFS
         /* If machine has AFS, set process authentication group. */
@@ -1771,7 +1768,7 @@ do_authenticated(struct passwd * pw)
 #endif /* XAUTH_PATH */
 
                 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
-                        if (no_agent_forwarding_flag) {
+                        if (no_agent_forwarding_flag || compat13) {
                                 debug("Authentication agent forwarding not permitted for this authentication.");
                                 goto fail;
                         }