1 files changed, 471 insertions, 0 deletions

diff --git a/other/ssharp/kex.c b/other/ssharp/kex.c
new file mode 100644
index 0000000..e0cee34
--- /dev/null
+++ b/other/ssharp/kex.c
@@ -0,0 +1,471 @@
+/*
+ * Copyright (c) 2000 Markus Friedl.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+RCSID("$OpenBSD: kex.c,v 1.33 2001/04/05 10:42:50 markus Exp $");
+
+#include <openssl/crypto.h>
+
+#include "ssh2.h"
+#include "xmalloc.h"
+#include "buffer.h"
+#include "bufaux.h"
+#include "packet.h"
+#include "compat.h"
+#include "cipher.h"
+#include "kex.h"
+#include "key.h"
+#include "log.h"
+#include "mac.h"
+#include "match.h"
+#include "dispatch.h"
+
+#define KEX_COOKIE_LEN  16
+
+void    kex_kexinit_finish(Kex *kex);
+void    kex_choose_conf(Kex *k);
+
+extern int SSH2_mim_only;
+extern char *SSH2_mim_cipher;
+
+/* put algorithm proposal into buffer */
+void
+kex_prop2buf(Buffer *b, char *proposal[PROPOSAL_MAX])
+{
+        u_int32_t rand = 0;
+        int i;
+
+        buffer_clear(b);
+        for (i = 0; i < KEX_COOKIE_LEN; i++) {
+                if (i % 4 == 0)
+                        rand = arc4random();
+                buffer_put_char(b, rand & 0xff);
+                rand >>= 8;
+        }
+        for (i = 0; i < PROPOSAL_MAX; i++)
+                buffer_put_cstring(b, proposal[i]);
+        buffer_put_char(b, 0);                  /* first_kex_packet_follows */
+        buffer_put_int(b, 0);                   /* uint32 reserved */
+}
+
+/* parse buffer and return algorithm proposal */
+char **
+kex_buf2prop(Buffer *raw)
+{
+        Buffer b;
+        int i;
+        char **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++)
+                buffer_get_char(&b);
+        /* extract kex init proposal strings */
+        for (i = 0; i < PROPOSAL_MAX; i++) {
+                proposal[i] = buffer_get_string(&b,NULL);
+                debug2("kex_parse_kexinit: %s", proposal[i]);
+        }
+        /* 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;
+}
+
+void
+kex_prop_free(char **proposal)
+{
+        int i;
+
+        for (i = 0; i < PROPOSAL_MAX; i++)
+                xfree(proposal[i]);
+        xfree(proposal);
+}
+
+void
+kex_protocol_error(int type, int plen, void *ctxt)
+{
+        error("Hm, kex protocol error: type %d plen %d", type, plen);
+}
+
+void
+kex_clear_dispatch(void)
+{
+        int i;
+
+        /* Numbers 30-49 are used for kex packets */
+        for (i = 30; i <= 49; i++)
+                dispatch_set(i, &kex_protocol_error);
+}
+
+void
+kex_finish(Kex *kex)
+{
+        int plen;
+
+        kex_clear_dispatch();
+
+        packet_start(SSH2_MSG_NEWKEYS);
+        packet_send();
+        /* packet_write_wait(); */
+        debug("SSH2_MSG_NEWKEYS sent");
+
+        debug("waiting for SSH2_MSG_NEWKEYS");
+        packet_read_expect(&plen, SSH2_MSG_NEWKEYS);
+        debug("SSH2_MSG_NEWKEYS received");
+
+        kex->done = 1;
+        buffer_clear(&kex->peer);
+        /* buffer_clear(&kex->my); */
+        kex->flags &= ~KEX_INIT_SENT;
+        xfree(kex->name);
+        kex->name = NULL;
+}
+
+void
+kex_send_kexinit(Kex *kex)
+{
+        if (kex == NULL) {
+                error("kex_send_kexinit: no kex, cannot rekey");
+                return;
+        }
+        if (kex->flags & KEX_INIT_SENT) {
+                debug("KEX_INIT_SENT");
+                return;
+        }
+        kex->done = 0;
+        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;
+}
+
+
+void
+kex_input_kexinit(int type, int plen, void *ctxt)
+{
+        char *ptr, *s;
+        int dlen;
+        int i;
+        Kex *kex = (Kex *)ctxt;
+
+        debug("SSH2_MSG_KEXINIT received");
+        if (kex == NULL)
+                fatal("kex_input_kexinit: no kex, cannot rekey");
+
+        ptr = packet_get_raw(&dlen);
+        buffer_append(&kex->peer, ptr, dlen);
+
+        /* discard packet */
+        for (i = 0; i < KEX_COOKIE_LEN; i++)
+                packet_get_char();
+        for (i = 0; i < PROPOSAL_MAX; i++) {
+                s = packet_get_string(NULL);
+                xfree(s);
+        }
+        packet_get_char();
+        packet_get_int();
+        packet_done();
+
+        kex_kexinit_finish(kex);
+}
+
+Kex *
+kex_setup(char *proposal[PROPOSAL_MAX])
+{
+        Kex *kex;
+
+        kex = xmalloc(sizeof(*kex));
+        memset(kex, 0, sizeof(*kex));
+        buffer_init(&kex->peer);
+        buffer_init(&kex->my);
+        kex_prop2buf(&kex->my, proposal);
+        kex->done = 0;
+
+        kex_send_kexinit(kex);                                  /* we start */
+        kex_clear_dispatch();
+        dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
+
+        return kex;
+}
+
+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);
+        }
+}
+
+void
+choose_enc(Enc *enc, char *client, char *server)
+{
+        char *name = match_list(client, server, NULL);
+        if (name == NULL)
+                fatal("no matching cipher found: client %s server %s", client, server);
+        enc->cipher = cipher_by_name(name);
+        if (enc->cipher == NULL)
+                fatal("matching cipher is not supported: %s", name);
+        enc->name = name;
+        enc->enabled = 0;
+        enc->iv = NULL;
+        enc->key = NULL;
+}
+void
+choose_mac(Mac *mac, char *client, char *server)
+{
+        char *name = match_list(client, server, NULL);
+        if (name == NULL)
+                fatal("no matching mac found: client %s server %s", client, server);
+        if (mac_init(mac, name) < 0)
+                fatal("unsupported mac %s", name);
+        /* truncate the key */
+        if (datafellows & SSH_BUG_HMAC)
+                mac->key_len = 16;
+        mac->name = name;
+        mac->key = NULL;
+        mac->enabled = 0;
+}
+void
+choose_comp(Comp *comp, char *client, char *server)
+{
+        char *name = match_list(client, server, NULL);
+        if (name == NULL)
+                fatal("no matching comp found: client %s server %s", client, server);
+        if (strcmp(name, "zlib") == 0) {
+                comp->type = 1;
+        } else if (strcmp(name, "none") == 0) {
+                comp->type = 0;
+        } else {
+                fatal("unsupported comp %s", name);
+        }
+        comp->name = name;
+}
+void
+choose_kex(Kex *k, char *client, char *server)
+{
+        k->name = match_list(client, server, NULL);
+        if (k->name == NULL)
+                fatal("no kex alg");
+        if (strcmp(k->name, KEX_DH1) == 0) {
+                k->kex_type = DH_GRP1_SHA1;
+        } else if (strcmp(k->name, KEX_DHGEX) == 0) {
+                k->kex_type = DH_GEX_SHA1;
+        } else
+                fatal("bad kex alg %s", k->name);
+}
+void
+choose_hostkeyalg(Kex *k, char *client, char *server)
+{
+        char *hostkeyalg = match_list(client, server, NULL);
+
+        /* SSHARP */
+        if (SSH2_mim_only) {
+                /* Do we already have a prefered cipher? */
+                if (SSH2_mim_cipher)
+                        hostkeyalg = strdup(SSH2_mim_cipher);
+                else {
+                        if (strchr(client, ','))
+                                hostkeyalg = strdup(strchr(client, ',')+1);
+                }
+                log("New hostkeyalg=%s", hostkeyalg);
+        }
+        if (hostkeyalg == NULL)
+                fatal("no hostkey alg");
+        k->hostkey_type = key_type_from_name(hostkeyalg);
+        if (k->hostkey_type == KEY_UNSPEC)
+                fatal("bad hostkey alg '%s'", hostkeyalg);
+        xfree(hostkeyalg);
+}
+
+void
+kex_choose_conf(Kex *kex)
+{
+        Newkeys *newkeys;
+        char **my, **peer;
+        char **cprop, **sprop;
+        int nenc, nmac, ncomp;
+        int mode;
+        int ctos;                               /* direction: if true client-to-server */
+        int need;
+
+        my   = kex_buf2prop(&kex->my);
+        peer = kex_buf2prop(&kex->peer);
+
+        if (kex->server) {
+                cprop=peer;
+                sprop=my;
+        } else {
+                cprop=my;
+                sprop=peer;
+        }
+
+        /* Algorithm Negotiation */
+        for (mode = 0; mode < MODE_MAX; mode++) {
+                newkeys = xmalloc(sizeof(*newkeys));
+                memset(newkeys, 0, sizeof(*newkeys));
+                kex->newkeys[mode] = newkeys;
+                ctos = (!kex->server && mode == MODE_OUT) || (kex->server && mode == MODE_IN);
+                nenc  = ctos ? PROPOSAL_ENC_ALGS_CTOS  : PROPOSAL_ENC_ALGS_STOC;
+                nmac  = ctos ? PROPOSAL_MAC_ALGS_CTOS  : PROPOSAL_MAC_ALGS_STOC;
+                ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC;
+                choose_enc (&newkeys->enc,  cprop[nenc],  sprop[nenc]);
+                choose_mac (&newkeys->mac,  cprop[nmac],  sprop[nmac]);
+                choose_comp(&newkeys->comp, cprop[ncomp], sprop[ncomp]);
+                debug("kex: %s %s %s %s",
+                    ctos ? "client->server" : "server->client",
+                    newkeys->enc.name,
+                    newkeys->mac.name,
+                    newkeys->comp.name);
+        }
+        choose_kex(kex, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]);
+        choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS],
+            sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]);
+        need = 0;
+        for (mode = 0; mode < MODE_MAX; mode++) {
+                newkeys = kex->newkeys[mode];
+                if (need < newkeys->enc.cipher->key_len)
+                        need = newkeys->enc.cipher->key_len;
+                if (need < newkeys->enc.cipher->block_size)
+                        need = newkeys->enc.cipher->block_size;
+                if (need < newkeys->mac.key_len)
+                        need = newkeys->mac.key_len;
+        }
+        /* XXX need runden? */
+        kex->we_need = need;
+
+        kex_prop_free(my);
+        kex_prop_free(peer);
+}
+
+u_char *
+derive_key(Kex *kex, 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(roundup(need, mdsz));
+
+        buffer_init(&b);
+        buffer_put_bignum2(&b, shared_secret);
+
+        /* K1 = HASH(K || H || "A" || session_id) */
+        EVP_DigestInit(&md, evp_md);
+        EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
+        EVP_DigestUpdate(&md, hash, mdsz);
+        EVP_DigestUpdate(&md, &c, 1);
+        EVP_DigestUpdate(&md, kex->session_id, kex->session_id_len);
+        EVP_DigestFinal(&md, digest, NULL);
+
+        /*
+         * expand key:
+         * Kn = HASH(K || H || K1 || K2 || ... || Kn-1)
+         * Key = K1 || K2 || ... || Kn
+         */
+        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;
+}
+
+Newkeys *current_keys[MODE_MAX];
+
+#define NKEYS   6
+void
+kex_derive_keys(Kex *kex, u_char *hash, BIGNUM *shared_secret)
+{
+        u_char *keys[NKEYS];
+        int i, mode, ctos;
+
+        for (i = 0; i < NKEYS; i++)
+                keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, shared_secret);
+
+        debug("kex_derive_keys");
+        for (mode = 0; mode < MODE_MAX; mode++) {
+                current_keys[mode] = kex->newkeys[mode];
+                kex->newkeys[mode] = NULL;
+                ctos = (!kex->server && mode == MODE_OUT) || (kex->server && mode == MODE_IN);
+                current_keys[mode]->enc.iv  = keys[ctos ? 0 : 1];
+                current_keys[mode]->enc.key = keys[ctos ? 2 : 3];
+                current_keys[mode]->mac.key = keys[ctos ? 4 : 5];
+        }
+}
+
+Newkeys *
+kex_get_newkeys(int mode)
+{
+        Newkeys *ret;
+
+        ret = current_keys[mode];
+        current_keys[mode] = NULL;
+        return ret;
+}
+
+#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