7 files changed, 284 insertions, 959 deletions

diff --git a/ChangeLog b/ChangeLog
index df8ebde1c..0a84a5257 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -6,6 +6,10 @@
    - stevesk@cvs.openbsd.org 2001/04/03 13:56:11
      [sftp-glob.c ssh-agent.c ssh-keygen.c]
      free() -> xfree()
+   - 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.
 
 20010403
  - OpenBSD CVS Sync
@@ -4816,4 +4820,4 @@
  - Wrote replacements for strlcpy and mkdtemp
  - Released 1.0pre1
 
-$Id: ChangeLog,v 1.1049 2001/04/04 01:53:20 mouring Exp $
+$Id: ChangeLog,v 1.1050 2001/04/04 01:56:17 mouring Exp $
diff --git a/dh.c b/dh.c
index 6c53b0038..03b9fd1b8 100644
--- a/dh.c
+++ b/dh.c
@@ -23,7 +23,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: dh.c,v 1.11 2001/03/29 21:17:39 markus Exp $");
+RCSID("$OpenBSD: dh.c,v 1.12 2001/04/03 19:53:29 markus Exp $");
 
 #include "xmalloc.h"
 
@@ -273,3 +273,22 @@ dh_new_group1(void)
 
         return (dh_new_group_asc(gen, group1));
 }
+
+/*
+ * 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) */
+}
diff --git a/dh.h b/dh.h
index 13d2fa162..e8b2944ce 100644
--- a/dh.h
+++ b/dh.h
@@ -1,4 +1,4 @@
-/*      $OpenBSD: dh.h,v 1.4 2001/03/29 21:17:39 markus Exp $   */
+/*      $OpenBSD: dh.h,v 1.5 2001/04/03 19:53:29 markus Exp $   */
 
 /*
  * Copyright (c) 2000 Niels Provos.  All rights reserved.
@@ -40,6 +40,8 @@ DH	*dh_new_group1(void);
 void    dh_gen_key(DH *, int);
 int     dh_pub_is_valid(DH *dh, BIGNUM *dh_pub);
 
+int     dh_estimate(int bits);
+
 #define DH_GRP_MIN      1024
 #define DH_GRP_MAX      8192
 
diff --git a/kex.c b/kex.c
index 576d4b56e..a0a5b46fe 100644
--- a/kex.c
+++ b/kex.c
@@ -23,12 +23,9 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: kex.c,v 1.25 2001/03/29 21:17:39 markus Exp $");
+RCSID("$OpenBSD: kex.c,v 1.26 2001/04/03 19:53:29 markus Exp $");
 
 #include <openssl/crypto.h>
-#include <openssl/bio.h>
-#include <openssl/bn.h>
-#include <openssl/pem.h>
 
 #include "ssh2.h"
 #include "xmalloc.h"
@@ -42,233 +39,169 @@ RCSID("$OpenBSD: kex.c,v 1.25 2001/03/29 21:17:39 markus Exp $");
 #include "log.h"
 #include "mac.h"
 #include "match.h"
+#include "dispatch.h"
 
 #define KEX_COOKIE_LEN  16
 
-Buffer *
-kex_init(char *myproposal[PROPOSAL_MAX])
+void    kex_kexinit_finish(Kex *kex);
+void    kex_choose_conf(Kex *k);
+
+/* put algorithm proposal into buffer */
+void
+kex_prop2buf(Buffer *b, char *proposal[PROPOSAL_MAX])
 {
-        int first_kex_packet_follows = 0;
-        u_char cookie[KEX_COOKIE_LEN];
         u_int32_t rand = 0;
         int i;
-        Buffer *ki = xmalloc(sizeof(*ki));
+
+        buffer_clear(b);
         for (i = 0; i < KEX_COOKIE_LEN; i++) {
                 if (i % 4 == 0)
                         rand = arc4random();
-                cookie[i] = rand & 0xff;
+                buffer_put_char(b, rand & 0xff);
                 rand >>= 8;
         }
-        buffer_init(ki);
-        buffer_append(ki, (char *)cookie, sizeof cookie);
         for (i = 0; i < PROPOSAL_MAX; i++)
-                buffer_put_cstring(ki, myproposal[i]);
-        buffer_put_char(ki, first_kex_packet_follows);
-        buffer_put_int(ki, 0);                          /* uint32 reserved */
-        return ki;
+                buffer_put_cstring(b, proposal[i]);
+        buffer_put_char(b, 0);                  /* first_kex_packet_follows */
+        buffer_put_int(b, 0);                   /* uint32 reserved */
 }
 
-/* send kexinit, parse and save reply */
-void
-kex_exchange_kexinit(
-    Buffer *my_kexinit, Buffer *peer_kexint,
-    char *peer_proposal[PROPOSAL_MAX])
+/* parse buffer and return algorithm proposal */
+char **
+kex_buf2prop(Buffer *raw)
 {
+        Buffer b;
         int i;
-        char *ptr;
-        int plen;
+        char **proposal;
 
-        debug("send KEXINIT");
-        packet_start(SSH2_MSG_KEXINIT);
-        packet_put_raw(buffer_ptr(my_kexinit), buffer_len(my_kexinit));
-        packet_send();
-        packet_write_wait();
-        debug("done");
-
-        /*
-         * read and save raw KEXINIT payload in buffer. this is used during
-         * computation of the session_id and the session keys.
-         */
-        debug("wait KEXINIT");
-        packet_read_expect(&plen, SSH2_MSG_KEXINIT);
-        ptr = packet_get_raw(&plen);
-        buffer_append(peer_kexint, ptr, plen);
-
-        /* parse packet and save algorithm proposal */
+        proposal = xmalloc(PROPOSAL_MAX * sizeof(char *));
+
+        buffer_init(&b);
+        buffer_append(&b, buffer_ptr(raw), buffer_len(raw));
         /* skip cookie */
         for (i = 0; i < KEX_COOKIE_LEN; i++)
-                packet_get_char();
+                buffer_get_char(&b);
         /* extract kex init proposal strings */
         for (i = 0; i < PROPOSAL_MAX; i++) {
-                peer_proposal[i] = packet_get_string(NULL);
-                debug("got kexinit: %s", peer_proposal[i]);
+                proposal[i] = buffer_get_string(&b,NULL);
+                debug2("kex_parse_kexinit: %s", proposal[i]);
         }
-        /* first kex follow / reserved */
-        i = packet_get_char();
-        debug("first kex follow: %d ", i);
-        i = packet_get_int();
-        debug("reserved: %d ", i);
-        packet_done();
-        debug("done");
+        /* first kex follows / reserved */
+        i = buffer_get_char(&b);
+        debug2("kex_parse_kexinit: first_kex_follows %d ", i);
+        i = buffer_get_int(&b);
+        debug2("kex_parse_kexinit: reserved %d ", i);
+        buffer_free(&b);
+        return proposal;
 }
 
-#ifdef DEBUG_KEX
 void
-dump_digest(u_char *digest, int len)
+kex_prop_free(char **proposal)
 {
         int i;
-        for (i = 0; i< len; i++){
-                fprintf(stderr, "%02x", digest[i]);
-                if(i%2!=0)
-                        fprintf(stderr, " ");
-        }
-        fprintf(stderr, "\n");
+
+        for (i = 0; i < PROPOSAL_MAX; i++)
+                xfree(proposal[i]);
+        xfree(proposal);
 }
-#endif
 
-u_char *
-kex_hash(
-    char *client_version_string,
-    char *server_version_string,
-    char *ckexinit, int ckexinitlen,
-    char *skexinit, int skexinitlen,
-    char *serverhostkeyblob, int sbloblen,
-    BIGNUM *client_dh_pub,
-    BIGNUM *server_dh_pub,
-    BIGNUM *shared_secret)
+void
+kex_protocol_error(int type, int plen, void *ctxt)
 {
-        Buffer b;
-        static u_char digest[EVP_MAX_MD_SIZE];
-        EVP_MD *evp_md = EVP_sha1();
-        EVP_MD_CTX md;
-
-        buffer_init(&b);
-        buffer_put_string(&b, client_version_string, strlen(client_version_string));
-        buffer_put_string(&b, server_version_string, strlen(server_version_string));
-
-        /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
-        buffer_put_int(&b, ckexinitlen+1);
-        buffer_put_char(&b, SSH2_MSG_KEXINIT);
-        buffer_append(&b, ckexinit, ckexinitlen);
-        buffer_put_int(&b, skexinitlen+1);
-        buffer_put_char(&b, SSH2_MSG_KEXINIT);
-        buffer_append(&b, skexinit, skexinitlen);
-
-        buffer_put_string(&b, serverhostkeyblob, sbloblen);
-        buffer_put_bignum2(&b, client_dh_pub);
-        buffer_put_bignum2(&b, server_dh_pub);
-        buffer_put_bignum2(&b, shared_secret);
-
-#ifdef DEBUG_KEX
-        buffer_dump(&b);
-#endif
+        error("Hm, kex protocol error: type %d plen %d", type, plen);
+}
 
-        EVP_DigestInit(&md, evp_md);
-        EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
-        EVP_DigestFinal(&md, digest, NULL);
+void
+kex_send_newkeys(void)
+{
+        packet_start(SSH2_MSG_NEWKEYS);
+        packet_send();
+        /* packet_write_wait(); */
+        debug("SSH2_MSG_NEWKEYS sent");
+}
 
-        buffer_free(&b);
+void
+kex_input_newkeys(int type, int plen, void *ctxt)
+{
+        Kex *kex = ctxt;
+        int i;
 
-#ifdef DEBUG_KEX
-        dump_digest(digest, evp_md->md_size);
-#endif
-        return digest;
+        debug("SSH2_MSG_NEWKEYS received");
+        kex->newkeys = 1;
+        for (i = 30; i <= 49; i++)
+                dispatch_set(i, &kex_protocol_error);
+        buffer_clear(&kex->peer);
+        buffer_clear(&kex->my);
+        kex->flags &= ~KEX_INIT_SENT;
 }
 
-u_char *
-kex_hash_gex(
-    char *client_version_string,
-    char *server_version_string,
-    char *ckexinit, int ckexinitlen,
-    char *skexinit, int skexinitlen,
-    char *serverhostkeyblob, int sbloblen,
-    int min, int wantbits, int max, BIGNUM *prime, BIGNUM *gen,
-    BIGNUM *client_dh_pub,
-    BIGNUM *server_dh_pub,
-    BIGNUM *shared_secret)
+void
+kex_send_kexinit(Kex *kex)
 {
-        Buffer b;
-        static u_char digest[EVP_MAX_MD_SIZE];
-        EVP_MD *evp_md = EVP_sha1();
-        EVP_MD_CTX md;
-
-        buffer_init(&b);
-        buffer_put_string(&b, client_version_string, strlen(client_version_string));
-        buffer_put_string(&b, server_version_string, strlen(server_version_string));
-
-        /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
-        buffer_put_int(&b, ckexinitlen+1);
-        buffer_put_char(&b, SSH2_MSG_KEXINIT);
-        buffer_append(&b, ckexinit, ckexinitlen);
-        buffer_put_int(&b, skexinitlen+1);
-        buffer_put_char(&b, SSH2_MSG_KEXINIT);
-        buffer_append(&b, skexinit, skexinitlen);
-
-        buffer_put_string(&b, serverhostkeyblob, sbloblen);
-        if (min == -1 || max == -1) 
-                buffer_put_int(&b, wantbits);
-        else {
-                buffer_put_int(&b, min);
-                buffer_put_int(&b, wantbits);
-                buffer_put_int(&b, max);
-        }
-        buffer_put_bignum2(&b, prime);
-        buffer_put_bignum2(&b, gen);
-        buffer_put_bignum2(&b, client_dh_pub);
-        buffer_put_bignum2(&b, server_dh_pub);
-        buffer_put_bignum2(&b, shared_secret);
+        packet_start(SSH2_MSG_KEXINIT);
+        packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my));
+        packet_send();
+        debug("SSH2_MSG_KEXINIT sent");
+        kex->flags |= KEX_INIT_SENT;
+}
 
-#ifdef DEBUG_KEX
-        buffer_dump(&b);
-#endif
+void
+kex_input_kexinit(int type, int plen, void *ctxt)
+{
+        char *ptr;
+        int dlen;
+        Kex *kex = (Kex *)ctxt;
 
-        EVP_DigestInit(&md, evp_md);
-        EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
-        EVP_DigestFinal(&md, digest, NULL);
+        dispatch_set(SSH2_MSG_KEXINIT, &kex_protocol_error);
+        debug("SSH2_MSG_KEXINIT received");
 
-        buffer_free(&b);
+        ptr = packet_get_raw(&dlen);
+        buffer_append(&kex->peer, ptr, dlen);
 
-#ifdef DEBUG_KEX
-        dump_digest(digest, evp_md->md_size);
-#endif
-        return digest;
+        kex_kexinit_finish(kex);
 }
 
-u_char *
-derive_key(int id, int need, u_char *hash, BIGNUM *shared_secret)
+Kex *
+kex_start(char *proposal[PROPOSAL_MAX])
 {
-        Buffer b;
-        EVP_MD *evp_md = EVP_sha1();
-        EVP_MD_CTX md;
-        char c = id;
-        int have;
-        int mdsz = evp_md->md_size;
-        u_char *digest = xmalloc(((need+mdsz-1)/mdsz)*mdsz);
-
-        buffer_init(&b);
-        buffer_put_bignum2(&b, shared_secret);
+        Kex *kex;
+        int i;
 
-        EVP_DigestInit(&md, evp_md);
-        EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));  /* shared_secret K */
-        EVP_DigestUpdate(&md, hash, mdsz);              /* transport-06 */
-        EVP_DigestUpdate(&md, &c, 1);                   /* key id */
-        EVP_DigestUpdate(&md, hash, mdsz);              /* session id */
-        EVP_DigestFinal(&md, digest, NULL);
+        kex = xmalloc(sizeof(*kex));
+        memset(kex, 0, sizeof(*kex));
+        buffer_init(&kex->peer);
+        buffer_init(&kex->my);
+        kex_prop2buf(&kex->my, proposal);
+        kex->newkeys = 0;
+
+        kex_send_kexinit(kex);                                  /* we start */
+        /* Numbers 30-49 are used for kex packets */
+        for (i = 30; i <= 49; i++)
+                dispatch_set(i, kex_protocol_error);
+
+        dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
+        dispatch_set(SSH2_MSG_NEWKEYS, &kex_input_newkeys);
+        return kex;
+}
 
-        /* expand */
-        for (have = mdsz; need > have; have += mdsz) {
-                EVP_DigestInit(&md, evp_md);
-                EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
-                EVP_DigestUpdate(&md, hash, mdsz);
-                EVP_DigestUpdate(&md, digest, have);
-                EVP_DigestFinal(&md, digest + have, NULL);
+void
+kex_kexinit_finish(Kex *kex)
+{
+        if (!(kex->flags & KEX_INIT_SENT))
+                kex_send_kexinit(kex);
+
+        kex_choose_conf(kex);
+
+        switch(kex->kex_type) {
+        case DH_GRP1_SHA1:
+                kexdh(kex);
+                break;
+        case DH_GEX_SHA1:
+                kexgex(kex);
+                break;
+        default:
+                fatal("Unsupported key exchange %d", kex->kex_type);
         }
-        buffer_free(&b);
-#ifdef DEBUG_KEX
-        fprintf(stderr, "Digest '%c'== ", c);
-        dump_digest(digest, need);
-#endif
-        return digest;
 }
 
 void
@@ -340,17 +273,25 @@ choose_hostkeyalg(Kex *k, char *client, char *server)
         xfree(hostkeyalg);
 }
 
-Kex *
-kex_choose_conf(char *cprop[PROPOSAL_MAX], char *sprop[PROPOSAL_MAX], int server)
+void
+kex_choose_conf(Kex *k)
 {
+        char **my, **peer;
+        char **cprop, **sprop;
         int mode;
         int ctos;                               /* direction: if true client-to-server */
         int need;
-        Kex *k;
 
-        k = xmalloc(sizeof(*k));
-        memset(k, 0, sizeof(*k));
-        k->server = server;
+        my   = kex_buf2prop(&k->my);
+        peer = kex_buf2prop(&k->peer);
+
+        if (k->server) {
+                cprop=peer;
+                sprop=my;
+        } else {
+                cprop=my;
+                sprop=peer;
+        }
 
         for (mode = 0; mode < MODE_MAX; mode++) {
                 int nenc, nmac, ncomp;
@@ -381,11 +322,51 @@ kex_choose_conf(char *cprop[PROPOSAL_MAX], char *sprop[PROPOSAL_MAX], int server
         }
         /* XXX need runden? */
         k->we_need = need;
-        return k;
+
+        kex_prop_free(my);
+        kex_prop_free(peer);
+
+}
+
+u_char *
+derive_key(int id, int need, u_char *hash, BIGNUM *shared_secret)
+{
+        Buffer b;
+        EVP_MD *evp_md = EVP_sha1();
+        EVP_MD_CTX md;
+        char c = id;
+        int have;
+        int mdsz = evp_md->md_size;
+        u_char *digest = xmalloc(((need+mdsz-1)/mdsz)*mdsz);
+
+        buffer_init(&b);
+        buffer_put_bignum2(&b, shared_secret);
+
+        EVP_DigestInit(&md, evp_md);
+        EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));  /* shared_secret K */
+        EVP_DigestUpdate(&md, hash, mdsz);              /* transport-06 */
+        EVP_DigestUpdate(&md, &c, 1);                   /* key id */
+        EVP_DigestUpdate(&md, hash, mdsz);              /* session id */
+        EVP_DigestFinal(&md, digest, NULL);
+
+        /* expand */
+        for (have = mdsz; need > have; have += mdsz) {
+                EVP_DigestInit(&md, evp_md);
+                EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
+                EVP_DigestUpdate(&md, hash, mdsz);
+                EVP_DigestUpdate(&md, digest, have);
+                EVP_DigestFinal(&md, digest + have, NULL);
+        }
+        buffer_free(&b);
+#ifdef DEBUG_KEX
+        fprintf(stderr, "key '%c'== ", c);
+        dump_digest("key", digest, need);
+#endif
+        return digest;
 }
 
 #define NKEYS   6
-int
+void
 kex_derive_keys(Kex *k, u_char *hash, BIGNUM *shared_secret)
 {
         int i;
@@ -402,5 +383,22 @@ kex_derive_keys(Kex *k, u_char *hash, BIGNUM *shared_secret)
                 k->enc[mode].key = keys[ctos ? 2 : 3];
                 k->mac[mode].key = keys[ctos ? 4 : 5];
         }
-        return 0;
 }
+
+#if defined(DEBUG_KEX) || defined(DEBUG_KEXDH)
+void
+dump_digest(char *msg, u_char *digest, int len)
+{
+        int i;
+
+        fprintf(stderr, "%s\n", msg);
+        for (i = 0; i< len; i++){
+                fprintf(stderr, "%02x", digest[i]);
+                if (i%32 == 31)
+                        fprintf(stderr, "\n");
+                else if (i%8 == 7)
+                        fprintf(stderr, " ");
+        }
+        fprintf(stderr, "\n");
+}
+#endif
diff --git a/kex.h b/kex.h
index 4cc87d527..58f6d82c0 100644
--- a/kex.h
+++ b/kex.h
@@ -1,4 +1,4 @@
-/*      $OpenBSD: kex.h,v 1.17 2001/03/29 21:17:40 markus Exp $ */
+/*      $OpenBSD: kex.h,v 1.18 2001/04/03 19:53:29 markus Exp $ */
 
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
@@ -28,6 +28,8 @@
 
 #include <openssl/evp.h>
 #include "buffer.h"
+#include "cipher.h"
+#include "key.h"
 
 #define KEX_DH1         "diffie-hellman-group1-sha1"
 #define KEX_DHGEX       "diffie-hellman-group-exchange-sha1"
@@ -82,6 +84,7 @@ struct Comp {
         int             enabled;
         char            *name;
 };
+#define KEX_INIT_SENT   0x0001
 struct Kex {
         Enc             enc [MODE_MAX];
         Mac             mac [MODE_MAX];
@@ -91,40 +94,31 @@ struct Kex {
         char            *name;
         int             hostkey_type;
         int             kex_type;
+
+        /* used during kex */
+        Buffer          my;
+        Buffer          peer;
+        int             newkeys;
+        int             flags;
+        void            *state;
+        char            *client_version_string;
+        char            *server_version_string;
+
+        int             (*check_host_key)(Key *hostkey);
+        Key             *(*load_host_key)(int type);
 };
 
-Buffer  *kex_init(char *myproposal[PROPOSAL_MAX]);
-void
-kex_exchange_kexinit(
-    Buffer *my_kexinit, Buffer *peer_kexint,
-    char *peer_proposal[PROPOSAL_MAX]);
-Kex *
-kex_choose_conf(char *cprop[PROPOSAL_MAX],
-    char *sprop[PROPOSAL_MAX], int server);
-int     kex_derive_keys(Kex *k, u_char *hash, BIGNUM *shared_secret);
+void    kex_derive_keys(Kex *k, u_char *hash, BIGNUM *shared_secret);
 void    packet_set_kex(Kex *k);
+Kex     *kex_start(char *proposal[PROPOSAL_MAX]);
+void    kex_send_newkeys(void);
+void    kex_protocol_error(int type, int plen, void *ctxt);
 
-u_char *
-kex_hash(
-    char *client_version_string,
-    char *server_version_string,
-    char *ckexinit, int ckexinitlen,
-    char *skexinit, int skexinitlen,
-    char *serverhostkeyblob, int sbloblen,
-    BIGNUM *client_dh_pub,
-    BIGNUM *server_dh_pub,
-    BIGNUM *shared_secret);
+void    kexdh(Kex *);
+void    kexgex(Kex *);
+
+#if defined(DEBUG_KEX) || defined(DEBUG_KEXDH)
+void    dump_digest(char *msg, u_char *digest, int len);
+#endif
 
-u_char *
-kex_hash_gex(
-    char *client_version_string,
-    char *server_version_string,
-    char *ckexinit, int ckexinitlen,
-    char *skexinit, int skexinitlen,
-    char *serverhostkeyblob, int sbloblen,
-    int min, int wantbits, int max,
-    BIGNUM *prime, BIGNUM *gen,
-    BIGNUM *client_dh_pub,
-    BIGNUM *server_dh_pub,
-    BIGNUM *shared_secret);
 #endif
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);
diff --git a/sshd.c b/sshd.c
index b5e2d0f6f..c54675962 100644
--- a/sshd.c
+++ b/sshd.c
@@ -40,7 +40,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: sshd.c,v 1.185 2001/03/29 23:42:01 djm Exp $");
+RCSID("$OpenBSD: sshd.c,v 1.186 2001/04/03 19:53:29 markus Exp $");
 
 #include <openssl/dh.h>
 #include <openssl/bn.h>
@@ -70,6 +70,7 @@ RCSID("$OpenBSD: sshd.c,v 1.185 2001/03/29 23:42:01 djm Exp $");
 #include "canohost.h"
 #include "auth.h"
 #include "misc.h"
+#include "dispatch.h"
 
 #ifdef LIBWRAP
 #include <tcpd.h>
@@ -1407,14 +1408,7 @@ do_ssh1_kex(void)
 void
 do_ssh2_kex(void)
 {
-        Buffer *server_kexinit;
-        Buffer *client_kexinit;
-        int payload_len;
-        int i;
         Kex *kex;
-        char *cprop[PROPOSAL_MAX];
-
-/* KEXINIT */
 
         if (options.ciphers != NULL) {
                 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
@@ -1431,36 +1425,14 @@ do_ssh2_kex(void)
         }
         myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
 
-        server_kexinit = kex_init(myproposal);
-        client_kexinit = xmalloc(sizeof(*client_kexinit));
-        buffer_init(client_kexinit);
-
-        /* algorithm negotiation */
-        kex_exchange_kexinit(server_kexinit, client_kexinit, cprop);
-        kex = kex_choose_conf(cprop, myproposal, 1);
-        for (i = 0; i < PROPOSAL_MAX; i++)
-                xfree(cprop[i]);
-
-        switch (kex->kex_type) {
-        case DH_GRP1_SHA1:
-                ssh_dh1_server(kex, client_kexinit, server_kexinit);
-                break;
-        case DH_GEX_SHA1:
-                ssh_dhgex_server(kex, client_kexinit, server_kexinit);
-                break;
-        default:
-                fatal("Unsupported key exchange %d", kex->kex_type);
-        }
-
-        debug("send SSH2_MSG_NEWKEYS.");
-        packet_start(SSH2_MSG_NEWKEYS);
-        packet_send();
-        packet_write_wait();
-        debug("done: send SSH2_MSG_NEWKEYS.");
+        kex = kex_start(myproposal);
+        kex->server = 1;
+        kex->client_version_string=client_version_string;
+        kex->server_version_string=server_version_string;
+        kex->load_host_key=&get_hostkey_by_type;
 
-        debug("Wait SSH2_MSG_NEWKEYS.");
-        packet_read_expect(&payload_len, SSH2_MSG_NEWKEYS);
-        debug("GOT SSH2_MSG_NEWKEYS.");
+        /* start key exchange */
+        dispatch_run(DISPATCH_BLOCK, &kex->newkeys, kex);
 
 #ifdef DEBUG_KEXDH
         /* send 1st encrypted/maced/compressed message */
@@ -1469,316 +1441,5 @@ do_ssh2_kex(void)
         packet_send();
         packet_write_wait();
 #endif
-
-        debug("done: KEX2.");
-}
-
-/*
- * SSH2 key exchange
- */
-
-/* diffie-hellman-group1-sha1 */
-
-void
-ssh_dh1_server(Kex *kex, Buffer *client_kexinit, Buffer *server_kexinit)
-{
-#ifdef DEBUG_KEXDH
-        int i;
-#endif
-        int payload_len, dlen;
-        int slen;
-        u_char *signature = NULL;
-        u_char *server_host_key_blob = NULL;
-        u_int sbloblen;
-        u_int klen, kout;
-        u_char *kbuf;
-        u_char *hash;
-        BIGNUM *shared_secret = 0;
-        DH *dh;
-        BIGNUM *dh_client_pub = 0;
-        Key *hostkey;
-
-        hostkey = get_hostkey_by_type(kex->hostkey_type);
-        if (hostkey == NULL)
-                fatal("Unsupported hostkey type %d", kex->hostkey_type);
-
-/* KEXDH */
-        /* generate DH key */
-        dh = dh_new_group1();                   /* XXX depends on 'kex' */
-        dh_gen_key(dh, kex->we_need * 8);
-
-        debug("Wait SSH2_MSG_KEXDH_INIT.");
-        packet_read_expect(&payload_len, SSH2_MSG_KEXDH_INIT);
-
-        /* key, cert */
-        dh_client_pub = BN_new();
-        if (dh_client_pub == NULL)
-                fatal("dh_client_pub == NULL");
-        packet_get_bignum2(dh_client_pub, &dlen);
-
-#ifdef DEBUG_KEXDH
-        fprintf(stderr, "\ndh_client_pub= ");
-        BN_print_fp(stderr, dh_client_pub);
-        fprintf(stderr, "\n");
-        debug("bits %d", BN_num_bits(dh_client_pub));
-#endif
-
-#ifdef DEBUG_KEXDH
-        fprintf(stderr, "\np= ");
-        BN_print_fp(stderr, dh->p);
-        fprintf(stderr, "\ng= ");
-        bn_print(dh->g);
-        fprintf(stderr, "\npub= ");
-        BN_print_fp(stderr, dh->pub_key);
-        fprintf(stderr, "\n");
-        DHparams_print_fp(stderr, dh);
-#endif
-        if (!dh_pub_is_valid(dh, dh_client_pub))
-                packet_disconnect("bad client public DH value");
-
-        klen = DH_size(dh);
-        kbuf = xmalloc(klen);
-        kout = DH_compute_key(kbuf, dh_client_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);
-
-        /* XXX precompute? */
-        key_to_blob(hostkey, &server_host_key_blob, &sbloblen);
-
-        /* calc H */                    /* XXX depends on 'kex' */
-        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),
-            (char *)server_host_key_blob, sbloblen,
-            dh_client_pub,
-            dh->pub_key,
-            shared_secret
-        );
-        buffer_free(client_kexinit);
-        buffer_free(server_kexinit);
-        xfree(client_kexinit);
-        xfree(server_kexinit);
-        BN_free(dh_client_pub);
-#ifdef DEBUG_KEXDH
-        fprintf(stderr, "hash == ");
-        for (i = 0; i< 20; i++)
-                fprintf(stderr, "%02x", (hash[i])&0xff);
-        fprintf(stderr, "\n");
-#endif
-        /* save session id := H */
-        /* XXX hashlen depends on KEX */
-        session_id2_len = 20;
-        session_id2 = xmalloc(session_id2_len);
-        memcpy(session_id2, hash, session_id2_len);
-
-        /* sign H */
-        /* XXX hashlen depends on KEX */
-        key_sign(hostkey, &signature, &slen, hash, 20);
-
-        destroy_sensitive_data();
-
-        /* send server hostkey, DH pubkey 'f' and singed H */
-        packet_start(SSH2_MSG_KEXDH_REPLY);
-        packet_put_string((char *)server_host_key_blob, sbloblen);
-        packet_put_bignum2(dh->pub_key);        /* f */
-        packet_put_string((char *)signature, slen);
-        packet_send();
-        xfree(signature);
-        xfree(server_host_key_blob);
-        packet_write_wait();
-
-        kex_derive_keys(kex, hash, shared_secret);
-        BN_clear_free(shared_secret);
-        packet_set_kex(kex);
-
-        /* have keys, free DH */
-        DH_free(dh);
-}
-
-/* diffie-hellman-group-exchange-sha1 */
-
-void
-ssh_dhgex_server(Kex *kex, Buffer *client_kexinit, Buffer *server_kexinit)
-{
-#ifdef DEBUG_KEXDH
-        int i;
-#endif
-        int payload_len, dlen;
-        int slen, nbits, type, min, max;
-        u_char *signature = NULL;
-        u_char *server_host_key_blob = NULL;
-        u_int sbloblen;
-        u_int klen, kout;
-        u_char *kbuf;
-        u_char *hash;
-        BIGNUM *shared_secret = 0;
-        DH *dh;
-        BIGNUM *dh_client_pub = 0;
-        Key *hostkey;
-
-        hostkey = get_hostkey_by_type(kex->hostkey_type);
-        if (hostkey == NULL)
-                fatal("Unsupported hostkey type %d", kex->hostkey_type);
-
-/* KEXDHGEX */
-        debug("Wait SSH2_MSG_KEX_DH_GEX_REQUEST.");
-        type = packet_read(&payload_len);
-        if (type != SSH2_MSG_KEX_DH_GEX_REQUEST_OLD &&
-            type != SSH2_MSG_KEX_DH_GEX_REQUEST)
-                packet_disconnect("Protocol error: expected type %d or %d, got %d",
-                    SSH2_MSG_KEX_DH_GEX_REQUEST_OLD,
-                    SSH2_MSG_KEX_DH_GEX_REQUEST,
-                    type);
-        if (type == SSH2_MSG_KEX_DH_GEX_REQUEST_OLD) {
-                nbits = packet_get_int();
-                min = DH_GRP_MIN;
-                max = DH_GRP_MAX;
-        } else {
-                min = packet_get_int();
-                nbits = packet_get_int();
-                max = packet_get_int();
-
-                min = MAX(DH_GRP_MIN, min);
-                max = MIN(DH_GRP_MAX, max);
-        }
-
-        if (max < min || nbits < min || max < nbits)
-                fatal("DH_GEX_REQUEST, bad parameters: %d !< %d !< %d",
-                    min, nbits, max);
-
-        dh = choose_dh(min, nbits, max);
-        if (dh == NULL)
-                packet_disconnect("Protocol error: no matching DH grp found");
-
-        debug("Sending SSH2_MSG_KEX_DH_GEX_GROUP.");
-        packet_start(SSH2_MSG_KEX_DH_GEX_GROUP);
-        packet_put_bignum2(dh->p);
-        packet_put_bignum2(dh->g);
-        packet_send();
-        packet_write_wait();
-
-        /* Compute our exchange value in parallel with the client */
-
-        dh_gen_key(dh, kex->we_need * 8);
-
-        debug("Wait SSH2_MSG_KEX_DH_GEX_INIT.");
-        packet_read_expect(&payload_len, SSH2_MSG_KEX_DH_GEX_INIT);
-
-        /* key, cert */
-        dh_client_pub = BN_new();
-        if (dh_client_pub == NULL)
-                fatal("dh_client_pub == NULL");
-        packet_get_bignum2(dh_client_pub, &dlen);
-
-#ifdef DEBUG_KEXDH
-        fprintf(stderr, "\ndh_client_pub= ");
-        BN_print_fp(stderr, dh_client_pub);
-        fprintf(stderr, "\n");
-        debug("bits %d", BN_num_bits(dh_client_pub));
-#endif
-
-#ifdef DEBUG_KEXDH
-        fprintf(stderr, "\np= ");
-        BN_print_fp(stderr, dh->p);
-        fprintf(stderr, "\ng= ");
-        bn_print(dh->g);
-        fprintf(stderr, "\npub= ");
-        BN_print_fp(stderr, dh->pub_key);
-        fprintf(stderr, "\n");
-        DHparams_print_fp(stderr, dh);
-#endif
-        if (!dh_pub_is_valid(dh, dh_client_pub))
-                packet_disconnect("bad client public DH value");
-
-        klen = DH_size(dh);
-        kbuf = xmalloc(klen);
-        kout = DH_compute_key(kbuf, dh_client_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);
-
-        /* XXX precompute? */
-        key_to_blob(hostkey, &server_host_key_blob, &sbloblen);
-
-        if (type == SSH2_MSG_KEX_DH_GEX_REQUEST_OLD) {
-                /* These values are not included in the hash */
-                min = -1;
-                max = -1;
-        }
-
-        /* calc H */                    /* XXX depends on 'kex' */
-        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),
-            (char *)server_host_key_blob, sbloblen,
-            min, nbits, max,
-            dh->p, dh->g,
-            dh_client_pub,
-            dh->pub_key,
-            shared_secret
-        );
-        buffer_free(client_kexinit);
-        buffer_free(server_kexinit);
-        xfree(client_kexinit);
-        xfree(server_kexinit);
-        BN_free(dh_client_pub);
-#ifdef DEBUG_KEXDH
-        fprintf(stderr, "hash == ");
-        for (i = 0; i< 20; i++)
-                fprintf(stderr, "%02x", (hash[i])&0xff);
-        fprintf(stderr, "\n");
-#endif
-        /* save session id := H */
-        /* XXX hashlen depends on KEX */
-        session_id2_len = 20;
-        session_id2 = xmalloc(session_id2_len);
-        memcpy(session_id2, hash, session_id2_len);
-
-        /* sign H */
-        /* XXX hashlen depends on KEX */
-        key_sign(hostkey, &signature, &slen, hash, 20);
-
-        destroy_sensitive_data();
-
-        /* send server hostkey, DH pubkey 'f' and singed H */
-        packet_start(SSH2_MSG_KEX_DH_GEX_REPLY);
-        packet_put_string((char *)server_host_key_blob, sbloblen);
-        packet_put_bignum2(dh->pub_key);        /* f */
-        packet_put_string((char *)signature, slen);
-        packet_send();
-        xfree(signature);
-        xfree(server_host_key_blob);
-        packet_write_wait();
-
-        kex_derive_keys(kex, hash, shared_secret);
-        BN_clear_free(shared_secret);
-        packet_set_kex(kex);
-
-        /* have keys, free DH */
-        DH_free(dh);
+        debug("KEX done");
 }