- markus@cvs.openbsd.org 2001/04/03 19:53:29

     [dh.c dh.h kex.c kex.h sshconnect2.c sshd.c]
     move kex to kex*.c, used dispatch_set() callbacks for kex. should
     make rekeying easier.

1 files changed, 28 insertions, 381 deletions

diff --git a/sshconnect2.c b/sshconnect2.c
index 460d614f0..4ed39a23e 100644
--- a/sshconnect2.c
+++ b/sshconnect2.c
@@ -23,7 +23,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: sshconnect2.c,v 1.60 2001/03/29 21:06:21 stevesk Exp $");
+RCSID("$OpenBSD: sshconnect2.c,v 1.61 2001/04/03 19:53:29 markus Exp $");
 
 #include <openssl/bn.h>
 #include <openssl/md5.h>
@@ -47,15 +47,12 @@ RCSID("$OpenBSD: sshconnect2.c,v 1.60 2001/03/29 21:06:21 stevesk Exp $");
 #include "authfile.h"
 #include "cli.h"
 #include "dh.h"
-#include "dispatch.h"
 #include "authfd.h"
 #include "log.h"
 #include "readconf.h"
 #include "readpass.h"
 #include "match.h"
-
-void ssh_dh1_client(Kex *, char *, struct sockaddr *, Buffer *, Buffer *);
-void ssh_dhgex_client(Kex *, char *, struct sockaddr *, Buffer *, Buffer *);
+#include "dispatch.h"
 
 /* import */
 extern char *client_version_string;
@@ -69,13 +66,24 @@ extern Options options;
 u_char *session_id2 = NULL;
 int session_id2_len = 0;
 
+char *xxx_host;
+struct sockaddr *xxx_hostaddr;
+
+int
+check_host_key_callback(Key *hostkey)
+{
+        check_host_key(xxx_host, xxx_hostaddr, hostkey,
+            options.user_hostfile2, options.system_hostfile2);
+        return 0;
+}
+
 void
 ssh_kex2(char *host, struct sockaddr *hostaddr)
 {
-        int i, plen;
         Kex *kex;
-        Buffer *client_kexinit, *server_kexinit;
-        char *sprop[PROPOSAL_MAX];
+
+        xxx_host = host;
+        xxx_hostaddr = hostaddr;
 
         if (options.ciphers == (char *)-1) {
                 log("No valid ciphers for protocol version 2 given, using defaults.");
@@ -101,46 +109,13 @@ ssh_kex2(char *host, struct sockaddr *hostaddr)
                 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
         }
 
-        /* buffers with raw kexinit messages */
-        server_kexinit = xmalloc(sizeof(*server_kexinit));
-        buffer_init(server_kexinit);
-        client_kexinit = kex_init(myproposal);
-
-        /* algorithm negotiation */
-        kex_exchange_kexinit(client_kexinit, server_kexinit, sprop);
-        kex = kex_choose_conf(myproposal, sprop, 0);
-        for (i = 0; i < PROPOSAL_MAX; i++)
-                xfree(sprop[i]);
-
-        /* server authentication and session key agreement */
-        switch(kex->kex_type) {
-        case DH_GRP1_SHA1:
-                ssh_dh1_client(kex, host, hostaddr,
-                               client_kexinit, server_kexinit);
-                break;
-        case DH_GEX_SHA1:
-                ssh_dhgex_client(kex, host, hostaddr, client_kexinit,
-                                 server_kexinit);
-                break;
-        default:
-                fatal("Unsupported key exchange %d", kex->kex_type);
-        }
-
-        buffer_free(client_kexinit);
-        buffer_free(server_kexinit);
-        xfree(client_kexinit);
-        xfree(server_kexinit);
+        kex = kex_start(myproposal);
+        kex->client_version_string=client_version_string;
+        kex->server_version_string=server_version_string;
+        kex->check_host_key=&check_host_key_callback;
 
-        debug("Wait SSH2_MSG_NEWKEYS.");
-        packet_read_expect(&plen, SSH2_MSG_NEWKEYS);
-        packet_done();
-        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.");
+        /* start key exchange */
+        dispatch_run(DISPATCH_BLOCK, &kex->newkeys, kex);
 
 #ifdef DEBUG_KEXDH
         /* send 1st encrypted/maced/compressed message */
@@ -149,339 +124,7 @@ ssh_kex2(char *host, struct sockaddr *hostaddr)
         packet_send();
         packet_write_wait();
 #endif
-        debug("done: KEX2.");
-}
-
-/* diffie-hellman-group1-sha1 */
-
-void
-ssh_dh1_client(Kex *kex, char *host, struct sockaddr *hostaddr,
-               Buffer *client_kexinit, Buffer *server_kexinit)
-{
-#ifdef DEBUG_KEXDH
-        int i;
-#endif
-        int plen, dlen;
-        u_int klen, kout;
-        char *signature = NULL;
-        u_int slen;
-        char *server_host_key_blob = NULL;
-        Key *server_host_key;
-        u_int sbloblen;
-        DH *dh;
-        BIGNUM *dh_server_pub = 0;
-        BIGNUM *shared_secret = 0;
-        u_char *kbuf;
-        u_char *hash;
-
-        debug("Sending SSH2_MSG_KEXDH_INIT.");
-        /* generate and send 'e', client DH public key */
-        dh = dh_new_group1();
-        dh_gen_key(dh, kex->we_need * 8);
-        packet_start(SSH2_MSG_KEXDH_INIT);
-        packet_put_bignum2(dh->pub_key);
-        packet_send();
-        packet_write_wait();
-
-#ifdef DEBUG_KEXDH
-        fprintf(stderr, "\np= ");
-        BN_print_fp(stderr, dh->p);
-        fprintf(stderr, "\ng= ");
-        BN_print_fp(stderr, dh->g);
-        fprintf(stderr, "\npub= ");
-        BN_print_fp(stderr, dh->pub_key);
-        fprintf(stderr, "\n");
-        DHparams_print_fp(stderr, dh);
-#endif
-
-        debug("Wait SSH2_MSG_KEXDH_REPLY.");
-
-        packet_read_expect(&plen, SSH2_MSG_KEXDH_REPLY);
-
-        debug("Got SSH2_MSG_KEXDH_REPLY.");
-
-        /* key, cert */
-        server_host_key_blob = packet_get_string(&sbloblen);
-        server_host_key = key_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,
-                       options.user_hostfile2, options.system_hostfile2);
-
-        /* 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= ");
-        BN_print_fp(stderr, dh_server_pub);
-        fprintf(stderr, "\n");
-        debug("bits %d", BN_num_bits(dh_server_pub));
-#endif
-
-        /* signed H */
-        signature = packet_get_string(&slen);
-        packet_done();
-
-        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);
-#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
-        );
-        xfree(server_host_key_blob);
-        DH_free(dh);
-        BN_free(dh_server_pub);
-#ifdef DEBUG_KEXDH
-        fprintf(stderr, "hash == ");
-        for (i = 0; i< 20; i++)
-                fprintf(stderr, "%02x", (hash[i])&0xff);
-        fprintf(stderr, "\n");
-#endif
-        if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1)
-                fatal("key_verify failed for server_host_key");
-        key_free(server_host_key);
-        xfree(signature);
-
-        kex_derive_keys(kex, hash, shared_secret);
-        BN_clear_free(shared_secret);
-        packet_set_kex(kex);
-
-        /* save session id */
-        session_id2_len = 20;
-        session_id2 = xmalloc(session_id2_len);
-        memcpy(session_id2, hash, session_id2_len);
-}
-
-/* diffie-hellman-group-exchange-sha1 */
-
-/*
- * Estimates the group order for a Diffie-Hellman group that has an
- * attack complexity approximately the same as O(2**bits).  Estimate
- * with:  O(exp(1.9223 * (ln q)^(1/3) (ln ln q)^(2/3)))
- */
-
-int
-dh_estimate(int bits)
-{
-
-        if (bits < 64)
-                return (512);   /* O(2**63) */
-        if (bits < 128)
-                return (1024);  /* O(2**86) */
-        if (bits < 192)
-                return (2048);  /* O(2**116) */
-        return (4096);          /* O(2**156) */
-}
-
-void
-ssh_dhgex_client(Kex *kex, char *host, struct sockaddr *hostaddr,
-                 Buffer *client_kexinit, Buffer *server_kexinit)
-{
-#ifdef DEBUG_KEXDH
-        int i;
-#endif
-        int plen, dlen;
-        u_int klen, kout;
-        char *signature = NULL;
-        u_int slen, nbits, min, max;
-        char *server_host_key_blob = NULL;
-        Key *server_host_key;
-        u_int sbloblen;
-        DH *dh;
-        BIGNUM *dh_server_pub = 0;
-        BIGNUM *shared_secret = 0;
-        BIGNUM *p = 0, *g = 0;
-        u_char *kbuf;
-        u_char *hash;
-
-        nbits = dh_estimate(kex->we_need * 8);
-
-        if (datafellows & SSH_OLD_DHGEX) {
-                debug("Sending SSH2_MSG_KEX_DH_GEX_REQUEST_OLD.");
-
-                /* Old GEX request */
-                packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST_OLD);
-                packet_put_int(nbits);
-                min = DH_GRP_MIN;
-                max = DH_GRP_MAX;
-        } else {
-                debug("Sending SSH2_MSG_KEX_DH_GEX_REQUEST.");
-
-                /* New GEX request */
-                min = DH_GRP_MIN;
-                max = DH_GRP_MAX;
-
-                packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST);
-                packet_put_int(min);
-                packet_put_int(nbits);
-                packet_put_int(max);
-        }
-        packet_send();
-        packet_write_wait();
-
-#ifdef DEBUG_KEXDH
-        fprintf(stderr, "\nmin = %d, nbits = %d, max = %d", min, nbits, max);
-#endif
-
-        debug("Wait SSH2_MSG_KEX_DH_GEX_GROUP.");
-
-        packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_GROUP);
-
-        debug("Got SSH2_MSG_KEX_DH_GEX_GROUP.");
-
-        if ((p = BN_new()) == NULL)
-                fatal("BN_new");
-        packet_get_bignum2(p, &dlen);
-        if ((g = BN_new()) == NULL)
-                fatal("BN_new");
-        packet_get_bignum2(g, &dlen);
-
-        if (BN_num_bits(p) < min || BN_num_bits(p) > max)
-                fatal("DH_GEX group out of range: %d !< %d !< %d",
-                    min, BN_num_bits(p), max);
-
-        dh = dh_new_group(g, p);
-
-        dh_gen_key(dh, kex->we_need * 8);
-
-#ifdef DEBUG_KEXDH
-        fprintf(stderr, "\np= ");
-        BN_print_fp(stderr, dh->p);
-        fprintf(stderr, "\ng= ");
-        BN_print_fp(stderr, dh->g);
-        fprintf(stderr, "\npub= ");
-        BN_print_fp(stderr, dh->pub_key);
-        fprintf(stderr, "\n");
-        DHparams_print_fp(stderr, dh);
-#endif
-
-        debug("Sending SSH2_MSG_KEX_DH_GEX_INIT.");
-        /* generate and send 'e', client DH public key */
-        packet_start(SSH2_MSG_KEX_DH_GEX_INIT);
-        packet_put_bignum2(dh->pub_key);
-        packet_send();
-        packet_write_wait();
-
-        debug("Wait SSH2_MSG_KEX_DH_GEX_REPLY.");
-
-        packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_REPLY);
-
-        debug("Got SSH2_MSG_KEXDH_REPLY.");
-
-        /* key, cert */
-        server_host_key_blob = packet_get_string(&sbloblen);
-        server_host_key = key_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,
-                       options.user_hostfile2, options.system_hostfile2);
-
-        /* 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= ");
-        BN_print_fp(stderr, dh_server_pub);
-        fprintf(stderr, "\n");
-        debug("bits %d", BN_num_bits(dh_server_pub));
-#endif
-
-        /* signed H */
-        signature = packet_get_string(&slen);
-        packet_done();
-
-        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);
-#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);
-
-        if (datafellows & SSH_OLD_DHGEX) {
-                /* These values are not included in the hash */
-                min = -1;
-                max = -1;
-        }
-
-        /* calc and verify H */
-        hash = kex_hash_gex(
-            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,
-            min, nbits, max,
-            dh->p, dh->g,
-            dh->pub_key,
-            dh_server_pub,
-            shared_secret
-        );
-        xfree(server_host_key_blob);
-        DH_free(dh);
-        BN_free(dh_server_pub);
-#ifdef DEBUG_KEXDH
-        fprintf(stderr, "hash == ");
-        for (i = 0; i< 20; i++)
-                fprintf(stderr, "%02x", (hash[i])&0xff);
-        fprintf(stderr, "\n");
-#endif
-        if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1)
-                fatal("key_verify failed for server_host_key");
-        key_free(server_host_key);
-        xfree(signature);
-
-        kex_derive_keys(kex, hash, shared_secret);
-        BN_clear_free(shared_secret);
-        packet_set_kex(kex);
-
-        /* save session id */
-        session_id2_len = 20;
-        session_id2 = xmalloc(session_id2_len);
-        memcpy(session_id2, hash, session_id2_len);
+        debug("done: ssh_kex2.");
 }
 
 /*
@@ -563,6 +206,7 @@ ssh_userauth2(const char *server_user, char *host)
         Authctxt authctxt;
         int type;
         int plen;
+        int i;
 
         if (options.challenge_reponse_authentication)
                 options.kbd_interactive_authentication = 1;
@@ -603,7 +247,10 @@ ssh_userauth2(const char *server_user, char *host)
         /* initial userauth request */
         userauth_none(&authctxt);
 
-        dispatch_init(&input_userauth_error);
+        //dispatch_init(&input_userauth_error);
+        for (i = 50; i <= 254; i++) {
+                dispatch_set(i, &input_userauth_error);
+        }
         dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
         dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
         dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);