- 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, 10 insertions, 349 deletions

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");
 }