- OpenBSD CVS update:

   - [channels.c]
     close efd on eof
   - [clientloop.c compat.c ssh.c sshconnect.c myproposal.h]
     ssh2 client implementation, interops w/ ssh.com and lsh servers.
   - [sshconnect.c]
     missing free.
   - [authfile.c cipher.c cipher.h packet.c sshconnect.c sshd.c]
     remove unused argument, split cipher_mask()
   - [clientloop.c]
     re-order: group ssh1 vs. ssh2
 - Make Redhat spec require openssl >= 0.9.5a

1 files changed, 333 insertions, 17 deletions

diff --git a/sshconnect.c b/sshconnect.c
index d64c0e2c0..2f9496090 100644
--- a/sshconnect.c
+++ b/sshconnect.c
@@ -5,27 +5,30 @@
  * Created: Sat Mar 18 22:15:47 1995 ylo
  * Code to connect to a remote host, and to perform the client side of the
  * login (authentication) dialog.
+ *
+ * SSH2 support added by Markus Friedl.
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: sshconnect.c,v 1.58 2000/03/23 22:15:33 markus Exp $");
+RCSID("$OpenBSD: sshconnect.c,v 1.61 2000/04/04 21:37:27 markus Exp $");
 
 #ifdef HAVE_OPENSSL
+#include <openssl/bn.h>
 #include <openssl/rsa.h>
 #include <openssl/dsa.h>
 #include <openssl/md5.h>
-#include <openssl/bn.h>
 #endif
 #ifdef HAVE_SSL
+#include <ssl/bn.h>
 #include <ssl/rsa.h>
 #include <ssl/dsa.h>
 #include <ssl/md5.h>
-#include <ssl/bn.h>
 #endif
 
 #include "xmalloc.h"
 #include "rsa.h"
 #include "ssh.h"
+#include "buffer.h"
 #include "packet.h"
 #include "authfd.h"
 #include "cipher.h"
@@ -33,7 +36,14 @@ RCSID("$OpenBSD: sshconnect.c,v 1.58 2000/03/23 22:15:33 markus Exp $");
 #include "uidswap.h"
 #include "compat.h"
 #include "readconf.h"
+
+#include "bufaux.h"
+
+#include "ssh2.h"
+#include "kex.h"
+#include "myproposal.h"
 #include "key.h"
+#include "dsa.h"
 #include "hostfile.h"
 
 /* Session id for the current session. */
@@ -42,6 +52,9 @@ unsigned char session_id[16];
 /* authentications supported by server */
 unsigned int supported_authentications;
 
+static char *client_version_string = NULL;
+static char *server_version_string = NULL;
+
 extern Options options;
 extern char *__progname;
 
@@ -957,6 +970,21 @@ try_password_authentication(char *prompt)
         return 0;
 }
 
+char *
+chop(char *s)
+{
+        char *t = s;
+        while (*t) {
+                if(*t == '\n' || *t == '\r') {
+                        *t = '\0';
+                        return s;
+                }
+                t++;
+        }
+        return s;
+
+}
+
 /*
  * Waits for the server identification string, and sends our own
  * identification string.
@@ -979,7 +1007,7 @@ ssh_exchange_identification()
                 if (buf[i] == '\r') {
                         buf[i] = '\n';
                         buf[i + 1] = 0;
-                        break;
+                        continue;               /**XXX wait for \n */
                 }
                 if (buf[i] == '\n') {
                         buf[i + 1] = 0;
@@ -987,17 +1015,21 @@ ssh_exchange_identification()
                 }
         }
         buf[sizeof(buf) - 1] = 0;
+        server_version_string = xstrdup(buf);
 
         /*
          * Check that the versions match.  In future this might accept
          * several versions and set appropriate flags to handle them.
          */
-        if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor,
-                   remote_version) != 3)
+        if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
+            &remote_major, &remote_minor, remote_version) != 3)
                 fatal("Bad remote protocol version identification: '%.100s'", buf);
         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.");
@@ -1010,6 +1042,10 @@ ssh_exchange_identification()
                         options.forward_agent = 0;
                 }
         }
+        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
@@ -1020,16 +1056,19 @@ ssh_exchange_identification()
                 fatal("Protocol major versions differ: %d vs. %d",
                       PROTOCOL_MAJOR, remote_major);
 #endif
-
         /* Send our own protocol version identification. */
         snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
-            PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION);
+            compat20 ? 2 : PROTOCOL_MAJOR,
+            compat20 ? 0 : PROTOCOL_MINOR,
+            SSH_VERSION);
         if (atomicio(write, connection_out, buf, strlen(buf)) != strlen(buf))
                 fatal("write: %.100s", strerror(errno));
+        client_version_string = xstrdup(buf);
+        chop(client_version_string);
+        chop(server_version_string);
+        debug("Local version string %.100s", client_version_string);
 }
 
-int ssh_cipher_default = SSH_CIPHER_3DES;
-
 int
 read_yes_or_no(const char *prompt, int defval)
 {
@@ -1283,6 +1322,278 @@ check_rsa_host_key(char *host, struct sockaddr *hostaddr, RSA *host_key)
 }
 
 /*
+ * SSH2 key exchange
+ */
+void
+ssh_kex2(char *host, struct sockaddr *hostaddr)
+{
+        Kex *kex;
+        char *cprop[PROPOSAL_MAX];
+        char *sprop[PROPOSAL_MAX];
+        Buffer *client_kexinit;
+        Buffer *server_kexinit;
+        int payload_len, dlen;
+        unsigned int klen, kout;
+        char *ptr;
+        char *signature = NULL;
+        unsigned int slen;
+        char *server_host_key_blob = NULL;
+        Key *server_host_key;
+        unsigned int sbloblen;
+        DH *dh;
+        BIGNUM *dh_server_pub = 0;
+        BIGNUM *shared_secret = 0;
+        int i;
+        unsigned char *kbuf;
+        unsigned char *hash;
+
+/* KEXINIT */
+
+        debug("Sending KEX init.");
+        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_STOC] = cipher_name(options.cipher);
+        }
+        if (options.compression) {
+                myproposal[PROPOSAL_COMP_ALGS_CTOS] = "zlib";
+                myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib";
+        } else {
+                myproposal[PROPOSAL_COMP_ALGS_CTOS] = "none";
+                myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
+        }
+        for (i = 0; i < PROPOSAL_MAX; i++)
+                cprop[i] = xstrdup(myproposal[i]);
+
+        client_kexinit = kex_init(cprop);
+        packet_start(SSH2_MSG_KEXINIT);
+        packet_put_raw(buffer_ptr(client_kexinit), buffer_len(client_kexinit)); 
+        packet_send();
+        packet_write_wait();
+
+        debug("done");
+
+        packet_read_expect(&payload_len, SSH2_MSG_KEXINIT);
+
+        /* save payload for session_id */
+        server_kexinit = xmalloc(sizeof(*server_kexinit));
+        buffer_init(server_kexinit);
+        ptr = packet_get_raw(&payload_len);
+        buffer_append(server_kexinit, ptr, payload_len);
+
+        /* skip cookie */
+        for (i = 0; i < 16; i++)
+                (void) packet_get_char();
+        /* kex init proposal strings */
+        for (i = 0; i < PROPOSAL_MAX; i++) {
+                sprop[i] = packet_get_string(NULL);
+                debug("got kexinit string: %s", sprop[i]);
+        }
+        i = (int) packet_get_char();
+        debug("first kex follow == %d", i);
+        i = packet_get_int();
+        debug("reserved == %d", i);
+
+        debug("done read kexinit");
+        kex = kex_choose_conf(cprop, sprop, 0);
+
+/* KEXDH */
+
+        debug("Sending SSH2_MSG_KEXDH_INIT.");
+
+        /* generate and send 'e', client DH public key */
+        dh = new_dh_group1();
+        packet_start(SSH2_MSG_KEXDH_INIT);
+        packet_put_bignum2(dh->pub_key);
+        packet_send();
+        packet_write_wait();
+
+#ifdef DEBUG_KEXDH
+        fprintf(stderr, "\np= ");
+        bignum_print(dh->p);
+        fprintf(stderr, "\ng= ");
+        bignum_print(dh->g);
+        fprintf(stderr, "\npub= ");
+        bignum_print(dh->pub_key);
+        fprintf(stderr, "\n");
+        DHparams_print_fp(stderr, dh);
+#endif
+
+        debug("Wait SSH2_MSG_KEXDH_REPLY.");
+
+        packet_read_expect(&payload_len, SSH2_MSG_KEXDH_REPLY);
+
+        debug("Got SSH2_MSG_KEXDH_REPLY.");
+
+        /* key, cert */
+        server_host_key_blob = packet_get_string(&sbloblen);
+        server_host_key = dsa_serverkey_from_blob(server_host_key_blob, sbloblen);
+        if (server_host_key == NULL)
+                fatal("cannot decode server_host_key_blob");
+
+        check_host_key(host, hostaddr, server_host_key);
+
+        /* DH paramter f, server public DH key */
+        dh_server_pub = BN_new();
+        if (dh_server_pub == NULL)
+                fatal("dh_server_pub == NULL");
+        packet_get_bignum2(dh_server_pub, &dlen);
+
+#ifdef DEBUG_KEXDH
+        fprintf(stderr, "\ndh_server_pub= ");
+        bignum_print(dh_server_pub);
+        fprintf(stderr, "\n");
+        debug("bits %d", BN_num_bits(dh_server_pub));
+#endif
+
+        /* signed H */
+        signature = packet_get_string(&slen);
+
+        klen = DH_size(dh);
+        kbuf = xmalloc(klen);
+        kout = DH_compute_key(kbuf, dh_server_pub, dh);
+#ifdef DEBUG_KEXDH
+        debug("shared secret: len %d/%d", klen, kout);
+        fprintf(stderr, "shared secret == ");
+        for (i = 0; i< kout; i++)
+                fprintf(stderr, "%02x", (kbuf[i])&0xff);
+        fprintf(stderr, "\n");
+#endif
+        shared_secret = BN_new();
+
+        BN_bin2bn(kbuf, kout, shared_secret);
+        memset(kbuf, 0, klen);
+        xfree(kbuf);
+
+        /* calc and verify H */
+        hash = kex_hash(
+            client_version_string,
+            server_version_string,
+            buffer_ptr(client_kexinit), buffer_len(client_kexinit),
+            buffer_ptr(server_kexinit), buffer_len(server_kexinit),
+            server_host_key_blob, sbloblen,
+            dh->pub_key,
+            dh_server_pub,
+            shared_secret
+        );
+        buffer_free(client_kexinit);
+        buffer_free(server_kexinit);
+        xfree(client_kexinit);
+        xfree(server_kexinit);
+#ifdef DEBUG_KEXDH
+        fprintf(stderr, "hash == ");
+        for (i = 0; i< 20; i++)
+                fprintf(stderr, "%02x", (hash[i])&0xff);
+        fprintf(stderr, "\n");
+#endif
+        dsa_verify(server_host_key, (unsigned char *)signature, slen, hash, 20);
+        key_free(server_host_key);
+
+        kex_derive_keys(kex, hash, shared_secret);
+        packet_set_kex(kex);
+
+        /* have keys, free DH */
+        DH_free(dh);
+
+        debug("Wait SSH2_MSG_NEWKEYS.");
+        packet_read_expect(&payload_len, SSH2_MSG_NEWKEYS);
+        debug("GOT SSH2_MSG_NEWKEYS.");
+
+        debug("send SSH2_MSG_NEWKEYS.");
+        packet_start(SSH2_MSG_NEWKEYS);
+        packet_send();
+        packet_write_wait();
+        debug("done: send SSH2_MSG_NEWKEYS.");
+
+        /* send 1st encrypted/maced/compressed message */
+        packet_start(SSH2_MSG_IGNORE);
+        packet_put_cstring("markus");
+        packet_send();
+        packet_write_wait();
+
+        debug("done: KEX2.");
+}
+/*
+ * Authenticate user
+ */
+void
+ssh_userauth2(int host_key_valid, RSA *own_host_key,
+    uid_t original_real_uid, char *host)
+{
+        int type;
+        int plen;
+        unsigned int dlen;
+        int partial;
+        struct passwd *pw;
+        char *server_user, *local_user;
+        char *auths;
+        char *password;
+        char *service = "ssh-connection";               // service name
+
+        debug("send SSH2_MSG_SERVICE_REQUEST");
+        packet_start(SSH2_MSG_SERVICE_REQUEST);
+        packet_put_cstring("ssh-userauth");
+        packet_send();
+        packet_write_wait();
+
+        type = packet_read(&plen);
+        if (type != SSH2_MSG_SERVICE_ACCEPT) {
+                fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type);
+        }
+        /* payload empty for ssh-2.0.13 ?? */
+        /* reply = packet_get_string(&payload_len); */
+        debug("got SSH2_MSG_SERVICE_ACCEPT");
+
+        /*XX COMMONCODE: */
+        /* Get local user name.  Use it as server user if no user name was given. */
+        pw = getpwuid(original_real_uid);
+        if (!pw)
+                fatal("User id %d not found from user database.", original_real_uid);
+        local_user = xstrdup(pw->pw_name);
+        server_user = options.user ? options.user : local_user;
+
+        /* INITIAL request for auth */
+        packet_start(SSH2_MSG_USERAUTH_REQUEST);
+        packet_put_cstring(server_user);
+        packet_put_cstring(service);
+        packet_put_cstring("none");
+        packet_send();
+        packet_write_wait();
+
+        for (;;) {
+                type = packet_read(&plen);
+                if (type == SSH2_MSG_USERAUTH_SUCCESS)
+                        break;
+                if (type != SSH2_MSG_USERAUTH_FAILURE)
+                        fatal("access denied: %d", type);
+                /* SSH2_MSG_USERAUTH_FAILURE means: try again */
+                auths = packet_get_string(&dlen);
+                debug("authentications that can continue: %s", auths);
+                partial = packet_get_char();
+                if (partial)
+                        debug("partial success");
+                if (strstr(auths, "password") == NULL)
+                        fatal("passwd auth not supported: %s", auths);
+                xfree(auths);
+                /* try passwd */
+                password = read_passphrase("password: ", 0);
+                packet_start(SSH2_MSG_USERAUTH_REQUEST);
+                packet_put_cstring(server_user);
+                packet_put_cstring(service);
+                packet_put_cstring("password");
+                packet_put_char(0);
+                packet_put_cstring(password);
+                memset(password, 0, strlen(password));
+                xfree(password);
+                packet_send();
+                packet_write_wait();
+        }
+        debug("ssh-userauth2 successfull");
+}
+
+/*
  * SSH1 key exchange
  */
 void
@@ -1293,6 +1604,7 @@ ssh_kex(char *host, struct sockaddr *hostaddr)
         RSA *host_key;
         RSA *public_key;
         int bits, rbits;
+        int ssh_cipher_default = SSH_CIPHER_3DES;
         unsigned char session_key[SSH_SESSION_KEY_LENGTH];
         unsigned char cookie[8];
         unsigned int supported_ciphers;
@@ -1427,7 +1739,7 @@ ssh_kex(char *host, struct sockaddr *hostaddr)
         RSA_free(host_key);
 
         if (options.cipher == SSH_CIPHER_NOT_SET) {
-                if (cipher_mask() & supported_ciphers & (1 << ssh_cipher_default))
+                if (cipher_mask1() & supported_ciphers & (1 << ssh_cipher_default))
                         options.cipher = ssh_cipher_default;
                 else {
                         debug("Cipher %s not supported, using %.100s instead.",
@@ -1640,12 +1952,16 @@ ssh_login(int host_key_valid, RSA *own_host_key, const char *orighost,
         /* Put the connection into non-blocking mode. */
         packet_set_nonblocking();
 
-        supported_authentications = 0;
         /* key exchange */
-        ssh_kex(host, hostaddr);
-        if (supported_authentications == 0)
-                fatal("supported_authentications == 0.");
-
         /* authenticate user */
-        ssh_userauth(host_key_valid, own_host_key, original_real_uid, host);
+        if (compat20) {
+                ssh_kex2(host, hostaddr);
+                ssh_userauth2(host_key_valid, own_host_key, original_real_uid, host);
+        } else {
+                supported_authentications = 0;
+                ssh_kex(host, hostaddr);
+                if (supported_authentications == 0)
+                        fatal("supported_authentications == 0.");
+                ssh_userauth(host_key_valid, own_host_key, original_real_uid, host);
+        }
 }