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* Copyright (c) 2001-2004 Simon Wilkinson. All rights reserved.
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#include <openssl/crypto.h>
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#include <openssl/bn.h>
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#include "monitor_wrap.h"
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kexgss_server(Kex *kex)
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OM_uint32 maj_status, min_status;
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* Some GSSAPI implementations use the input value of ret_flags (an
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* output variable) as a means of triggering mechanism specific
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* features. Initializing it to zero avoids inadvertently
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* activating this non-standard behaviour.
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OM_uint32 ret_flags = 0;
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gss_buffer_desc gssbuf, send_tok, recv_tok, msg_tok;
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unsigned int klen, kout;
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unsigned char *kbuf, *hash;
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BIGNUM *shared_secret = NULL;
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BIGNUM *dh_client_pub = NULL;
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/* Initialise GSSAPI */
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debug2("%s: Identifying %s", __func__, kex->name);
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oid = ssh_gssapi_id_kex(NULL, kex->name);
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fatal("Unknown gssapi mechanism");
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debug2("%s: Acquiring credentials", __func__);
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if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, oid))))
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fatal("Unable to acquire credentials for the server");
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debug("Wait SSH2_MSG_GSSAPI_INIT");
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case SSH2_MSG_KEXGSS_INIT:
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if (dh_client_pub != NULL)
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fatal("Received KEXGSS_INIT after initialising");
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recv_tok.value = packet_get_string(&slen);
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recv_tok.length = slen;
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dh_client_pub = BN_new();
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if (dh_client_pub == NULL)
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fatal("dh_client_pub == NULL");
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packet_get_bignum2(dh_client_pub);
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/* Send SSH_MSG_KEXGSS_HOSTKEY here, if we want */
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case SSH2_MSG_KEXGSS_CONTINUE:
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recv_tok.value = packet_get_string(&slen);
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recv_tok.length = slen;
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"Protocol error: didn't expect packet type %d",
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maj_status = PRIVSEP(ssh_gssapi_accept_ctx(ctxt, &recv_tok,
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&send_tok, &ret_flags));
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gss_release_buffer(&min_status, &recv_tok);
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if (maj_status != GSS_S_COMPLETE && send_tok.length == 0)
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fatal("Zero length token output when incomplete");
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if (dh_client_pub == NULL)
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fatal("No client public key");
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if (maj_status & GSS_S_CONTINUE_NEEDED) {
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debug("Sending GSSAPI_CONTINUE");
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packet_start(SSH2_MSG_KEXGSS_CONTINUE);
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packet_put_string(send_tok.value, send_tok.length);
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gss_release_buffer(&min_status, &send_tok);
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} while (maj_status & GSS_S_CONTINUE_NEEDED);
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if (GSS_ERROR(maj_status)) {
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if (send_tok.length>0) {
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packet_start(SSH2_MSG_KEXGSS_CONTINUE);
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packet_put_string(send_tok.value, send_tok.length);
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fatal("accept_ctx died");
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if (!(ret_flags & GSS_C_MUTUAL_FLAG))
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fatal("Mutual Authentication flag wasn't set");
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if (!(ret_flags & GSS_C_INTEG_FLAG))
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fatal("Integrity flag wasn't set");
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dh = dh_new_group1();
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dh_gen_key(dh, kex->we_need * 8);
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if (!dh_pub_is_valid(dh, dh_client_pub))
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packet_disconnect("bad client public DH value");
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kbuf = xmalloc(klen);
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kout = DH_compute_key(kbuf, dh_client_pub, dh);
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shared_secret = BN_new();
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BN_bin2bn(kbuf, kout, shared_secret);
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memset(kbuf, 0, klen);
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/* The GSSAPI hash is identical to the Diffie Helman one */
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kex->client_version_string, kex->server_version_string,
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buffer_ptr(&kex->peer), buffer_len(&kex->peer),
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buffer_ptr(&kex->my), buffer_len(&kex->my),
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NULL, 0, /* Change this if we start sending host keys */
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dh_client_pub, dh->pub_key, shared_secret
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BN_free(dh_client_pub);
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if (kex->session_id == NULL) {
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kex->session_id_len = 20;
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kex->session_id = xmalloc(kex->session_id_len);
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memcpy(kex->session_id, hash, kex->session_id_len);
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gssbuf.length = 20; /* Hashlen appears to always be 20 */
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if (GSS_ERROR(PRIVSEP(ssh_gssapi_sign(ctxt,&gssbuf,&msg_tok))))
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fatal("Couldn't get MIC");
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packet_start(SSH2_MSG_KEXGSS_COMPLETE);
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packet_put_bignum2(dh->pub_key);
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packet_put_string((char *)msg_tok.value,msg_tok.length);
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if (send_tok.length!=0) {
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packet_put_char(1); /* true */
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packet_put_string((char *)send_tok.value, send_tok.length);
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packet_put_char(0); /* false */
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gss_release_buffer(&min_status, &send_tok);
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if (gss_kex_context == NULL)
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gss_kex_context = ctxt;
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ssh_gssapi_delete_ctx(&ctxt);
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kex_derive_keys(kex, hash, shared_secret);
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BN_clear_free(shared_secret);
added
removed
kexgsss.c
