+/* $OpenBSD: kexdh.c,v 1.23 2006/08/03 03:34:42 deraadt Exp $ */
/*
* Copyright (c) 2001 Markus Friedl. All rights reserved.
*
*/
#include "includes.h"
-RCSID("$OpenBSD: kexdh.c,v 1.13 2002/01/25 22:07:40 markus Exp $");
-#include <openssl/crypto.h>
-#include <openssl/bn.h>
+#include <sys/types.h>
+
+#include <signal.h>
+
+#include <openssl/evp.h>
-#include "xmalloc.h"
#include "buffer.h"
-#include "bufaux.h"
+#include "ssh2.h"
#include "key.h"
+#include "cipher.h"
#include "kex.h"
-#include "log.h"
-#include "packet.h"
-#include "dh.h"
-#include "ssh2.h"
-static u_char *
+void
kex_dh_hash(
char *client_version_string,
char *server_version_string,
u_char *serverhostkeyblob, int sbloblen,
BIGNUM *client_dh_pub,
BIGNUM *server_dh_pub,
- BIGNUM *shared_secret)
+ BIGNUM *shared_secret,
+ u_char **hash, u_int *hashlen)
{
Buffer b;
static u_char digest[EVP_MAX_MD_SIZE];
- EVP_MD *evp_md = EVP_sha1();
+ const EVP_MD *evp_md = EVP_sha1();
EVP_MD_CTX md;
buffer_init(&b);
#ifdef DEBUG_KEX
dump_digest("hash", digest, EVP_MD_size(evp_md));
#endif
- return digest;
-}
-
-/* client */
-
-static void
-kexdh_client(Kex *kex)
-{
- BIGNUM *dh_server_pub = NULL, *shared_secret = NULL;
- DH *dh;
- Key *server_host_key;
- u_char *server_host_key_blob = NULL, *signature = NULL;
- u_char *kbuf, *hash;
- u_int klen, kout, slen, sbloblen;
-
- /* 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();
-
- debug("sending SSH2_MSG_KEXDH_INIT");
-#ifdef DEBUG_KEXDH
- DHparams_print_fp(stderr, dh);
- fprintf(stderr, "pub= ");
- BN_print_fp(stderr, dh->pub_key);
- fprintf(stderr, "\n");
-#endif
-
- debug("expecting SSH2_MSG_KEXDH_REPLY");
- packet_read_expect(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");
-
- if (kex->verify_host_key == NULL)
- fatal("cannot verify server_host_key");
- if (kex->verify_host_key(server_host_key) == -1)
- fatal("server_host_key verification failed");
-
- /* DH paramter f, server public DH key */
- if ((dh_server_pub = BN_new()) == NULL)
- fatal("dh_server_pub == NULL");
- packet_get_bignum2(dh_server_pub);
-
-#ifdef DEBUG_KEXDH
- fprintf(stderr, "dh_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_check_eom();
-
- 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
- dump_digest("shared secret", kbuf, kout);
-#endif
- if ((shared_secret = BN_new()) == NULL)
- fatal("kexdh_client: BN_new failed");
- BN_bin2bn(kbuf, kout, shared_secret);
- memset(kbuf, 0, klen);
- xfree(kbuf);
-
- /* calc and verify H */
- hash = kex_dh_hash(
- kex->client_version_string,
- kex->server_version_string,
- buffer_ptr(&kex->my), buffer_len(&kex->my),
- buffer_ptr(&kex->peer), buffer_len(&kex->peer),
- server_host_key_blob, sbloblen,
- dh->pub_key,
- dh_server_pub,
- shared_secret
- );
- xfree(server_host_key_blob);
- BN_clear_free(dh_server_pub);
- DH_free(dh);
-
- if (key_verify(server_host_key, signature, slen, hash, 20) != 1)
- fatal("key_verify failed for server_host_key");
- key_free(server_host_key);
- xfree(signature);
-
- /* save session id */
- if (kex->session_id == NULL) {
- kex->session_id_len = 20;
- kex->session_id = xmalloc(kex->session_id_len);
- memcpy(kex->session_id, hash, kex->session_id_len);
- }
-
- kex_derive_keys(kex, hash, shared_secret);
- BN_clear_free(shared_secret);
- kex_finish(kex);
-}
-
-/* server */
-
-static void
-kexdh_server(Kex *kex)
-{
- BIGNUM *shared_secret = NULL, *dh_client_pub = NULL;
- DH *dh;
- Key *server_host_key;
- u_char *kbuf, *hash, *signature = NULL, *server_host_key_blob = NULL;
- u_int sbloblen, klen, kout;
- int slen;
-
- /* generate server DH public key */
- dh = dh_new_group1();
- dh_gen_key(dh, kex->we_need * 8);
-
- debug("expecting SSH2_MSG_KEXDH_INIT");
- packet_read_expect(SSH2_MSG_KEXDH_INIT);
-
- if (kex->load_host_key == NULL)
- fatal("Cannot load hostkey");
- server_host_key = kex->load_host_key(kex->hostkey_type);
- if (server_host_key == NULL)
- fatal("Unsupported hostkey type %d", kex->hostkey_type);
-
- /* key, cert */
- if ((dh_client_pub = BN_new()) == NULL)
- fatal("dh_client_pub == NULL");
- packet_get_bignum2(dh_client_pub);
-
-#ifdef DEBUG_KEXDH
- fprintf(stderr, "dh_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
- DHparams_print_fp(stderr, dh);
- fprintf(stderr, "pub= ");
- BN_print_fp(stderr, dh->pub_key);
- fprintf(stderr, "\n");
-#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
- dump_digest("shared secret", kbuf, kout);
-#endif
- if ((shared_secret = BN_new()) == NULL)
- fatal("kexdh_server: BN_new failed");
- BN_bin2bn(kbuf, kout, shared_secret);
- memset(kbuf, 0, klen);
- xfree(kbuf);
-
- key_to_blob(server_host_key, &server_host_key_blob, &sbloblen);
-
- /* calc H */
- hash = kex_dh_hash(
- kex->client_version_string,
- kex->server_version_string,
- buffer_ptr(&kex->peer), buffer_len(&kex->peer),
- buffer_ptr(&kex->my), buffer_len(&kex->my),
- server_host_key_blob, sbloblen,
- dh_client_pub,
- dh->pub_key,
- shared_secret
- );
- BN_clear_free(dh_client_pub);
-
- /* save session id := H */
- /* XXX hashlen depends on KEX */
- if (kex->session_id == NULL) {
- kex->session_id_len = 20;
- kex->session_id = xmalloc(kex->session_id_len);
- memcpy(kex->session_id, hash, kex->session_id_len);
- }
-
- /* sign H */
- /* XXX hashlen depends on KEX */
- key_sign(server_host_key, &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(server_host_key_blob, sbloblen);
- packet_put_bignum2(dh->pub_key); /* f */
- packet_put_string(signature, slen);
- packet_send();
-
- xfree(signature);
- xfree(server_host_key_blob);
- /* have keys, free DH */
- DH_free(dh);
-
- kex_derive_keys(kex, hash, shared_secret);
- BN_clear_free(shared_secret);
- kex_finish(kex);
-}
-
-void
-kexdh(Kex *kex)
-{
- if (kex->server)
- kexdh_server(kex);
- else
- kexdh_client(kex);
+ *hash = digest;
+ *hashlen = EVP_MD_size(evp_md);
}
andersk / openssh.git / blobdiff