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sshconnect2.c
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/* $OpenBSD: sshconnect2.c,v 1.255 2017/03/11 23:40:26 djm Exp $ */
/*
* Copyright (c) 2000 Markus Friedl. All rights reserved.
* Copyright (c) 2008 Damien Miller. 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.
*/
/**************************************************************************/
/* */
/* Copyright (c) 2001, 2011 NoMachine, http://www.nomachine.com/. */
/* */
/* NXSSH, NX protocol compression and NX extensions to this software */
/* are copyright of NoMachine. Redistribution and use of the present */
/* software is allowed according to terms specified in the file LICENSE */
/* which comes in the source distribution. */
/* */
/* Check http://www.nomachine.com/licensing.html for applicability. */
/* */
/* NX and NoMachine are trademarks of Medialogic S.p.A. */
/* */
/* All rights reserved. */
/* */
/**************************************************************************/
#include "includes.h"
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <pwd.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) && !defined(BROKEN_STRNVIS)
#include <vis.h>
#endif
#include "openbsd-compat/sys-queue.h"
#include "xmalloc.h"
#include "ssh.h"
#include "ssh2.h"
#include "buffer.h"
#include "packet.h"
#include "compat.h"
#include "cipher.h"
#include "key.h"
#include "kex.h"
#include "myproposal.h"
#include "sshconnect.h"
#include "authfile.h"
#include "dh.h"
#include "authfd.h"
#include "log.h"
#include "misc.h"
#include "readconf.h"
#include "match.h"
#include "dispatch.h"
#include "canohost.h"
#include "msg.h"
#include "pathnames.h"
#include "uidswap.h"
#include "hostfile.h"
#include "ssherr.h"
#include "utf8.h"
#ifdef GSSAPI
#include "ssh-gss.h"
#endif
/* import */
extern char *client_version_string;
extern char *server_version_string;
extern Options options;
extern int NxAuthOnlyModeEnabled;
extern int NXServerMode;
extern int NxAdminModeEnabled;
extern int NXStdinPassEnabled;
/*
* SSH2 key exchange
*/
u_char *session_id2 = NULL;
u_int session_id2_len = 0;
char *xxx_host;
struct sockaddr *xxx_hostaddr;
static int
verify_host_key_callback(Key *hostkey, struct ssh *ssh)
{
if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
fatal("Host key verification failed.");
return 0;
}
static char *
order_hostkeyalgs(char *host, struct sockaddr *hostaddr, u_short port)
{
char *oavail, *avail, *first, *last, *alg, *hostname, *ret;
size_t maxlen;
struct hostkeys *hostkeys;
int ktype;
u_int i;
/* Find all hostkeys for this hostname */
get_hostfile_hostname_ipaddr(host, hostaddr, port, &hostname, NULL);
hostkeys = init_hostkeys();
for (i = 0; i < options.num_user_hostfiles; i++)
load_hostkeys(hostkeys, hostname, options.user_hostfiles[i]);
for (i = 0; i < options.num_system_hostfiles; i++)
load_hostkeys(hostkeys, hostname, options.system_hostfiles[i]);
oavail = avail = xstrdup(KEX_DEFAULT_PK_ALG);
maxlen = strlen(avail) + 1;
first = xmalloc(maxlen);
last = xmalloc(maxlen);
*first = *last = '\0';
#define ALG_APPEND(to, from) \
do { \
if (*to != '\0') \
strlcat(to, ",", maxlen); \
strlcat(to, from, maxlen); \
} while (0)
while ((alg = strsep(&avail, ",")) && *alg != '\0') {
if ((ktype = sshkey_type_from_name(alg)) == KEY_UNSPEC)
fatal("%s: unknown alg %s", __func__, alg);
if (lookup_key_in_hostkeys_by_type(hostkeys,
sshkey_type_plain(ktype), NULL))
ALG_APPEND(first, alg);
else
ALG_APPEND(last, alg);
}
#undef ALG_APPEND
xasprintf(&ret, "%s%s%s", first,
(*first == '\0' || *last == '\0') ? "" : ",", last);
if (*first != '\0')
debug3("%s: prefer hostkeyalgs: %s", __func__, first);
free(first);
free(last);
free(hostname);
free(oavail);
free_hostkeys(hostkeys);
return ret;
}
void
ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port)
{
char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
char *s;
struct kex *kex;
int r;
xxx_host = host;
xxx_hostaddr = hostaddr;
if ((s = kex_names_cat(options.kex_algorithms, "ext-info-c")) == NULL)
fatal("%s: kex_names_cat", __func__);
myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(s);
myproposal[PROPOSAL_ENC_ALGS_CTOS] =
compat_cipher_proposal(options.ciphers);
myproposal[PROPOSAL_ENC_ALGS_STOC] =
compat_cipher_proposal(options.ciphers);
myproposal[PROPOSAL_COMP_ALGS_CTOS] =
myproposal[PROPOSAL_COMP_ALGS_STOC] = options.compression ?
"zlib@openssh.com,zlib,none" : "none,zlib@openssh.com,zlib";
myproposal[PROPOSAL_MAC_ALGS_CTOS] =
myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
if (options.hostkeyalgorithms != NULL) {
if (kex_assemble_names(KEX_DEFAULT_PK_ALG,
&options.hostkeyalgorithms) != 0)
fatal("%s: kex_assemble_namelist", __func__);
myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
compat_pkalg_proposal(options.hostkeyalgorithms);
} else {
/* Enforce default */
options.hostkeyalgorithms = xstrdup(KEX_DEFAULT_PK_ALG);
/* Prefer algorithms that we already have keys for */
myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
compat_pkalg_proposal(
order_hostkeyalgs(host, hostaddr, port));
}
if (options.rekey_limit || options.rekey_interval)
packet_set_rekey_limits((u_int32_t)options.rekey_limit,
(time_t)options.rekey_interval);
/* start key exchange */
if ((r = kex_setup(active_state, myproposal)) != 0)
fatal("kex_setup: %s", ssh_err(r));
kex = active_state->kex;
#ifdef WITH_OPENSSL
kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
kex->kex[KEX_DH_GRP14_SHA256] = kexdh_client;
kex->kex[KEX_DH_GRP16_SHA512] = kexdh_client;
kex->kex[KEX_DH_GRP18_SHA512] = kexdh_client;
kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
# ifdef OPENSSL_HAS_ECC
kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
# endif
#endif
kex->kex[KEX_C25519_SHA256] = kexc25519_client;
kex->client_version_string=client_version_string;
kex->server_version_string=server_version_string;
kex->verify_host_key=&verify_host_key_callback;
dispatch_run(DISPATCH_BLOCK, &kex->done, active_state);
/* remove ext-info from the KEX proposals for rekeying */
myproposal[PROPOSAL_KEX_ALGS] =
compat_kex_proposal(options.kex_algorithms);
if ((r = kex_prop2buf(kex->my, myproposal)) != 0)
fatal("kex_prop2buf: %s", ssh_err(r));
session_id2 = kex->session_id;
session_id2_len = kex->session_id_len;
#ifdef DEBUG_KEXDH
/* send 1st encrypted/maced/compressed message */
packet_start(SSH2_MSG_IGNORE);
packet_put_cstring("markus");
packet_send();
packet_write_wait();
#endif
}
/*
* Authenticate user
*/
typedef struct cauthctxt Authctxt;
typedef struct cauthmethod Authmethod;
typedef struct identity Identity;
typedef struct idlist Idlist;
struct identity {
TAILQ_ENTRY(identity) next;
int agent_fd; /* >=0 if agent supports key */
struct sshkey *key; /* public/private key */
char *filename; /* comment for agent-only keys */
int tried;
int isprivate; /* key points to the private key */
int userprovided;
};
TAILQ_HEAD(idlist, identity);
struct cauthctxt {
const char *server_user;
const char *local_user;
const char *host;
const char *service;
struct cauthmethod *method;
sig_atomic_t success;
char *authlist;
int attempt;
/* pubkey */
struct idlist keys;
int agent_fd;
/* hostbased */
Sensitive *sensitive;
char *oktypes, *ktypes;
const char *active_ktype;
/* kbd-interactive */
int info_req_seen;
/* generic */
void *methoddata;
};
struct cauthmethod {
char *name; /* string to compare against server's list */
int (*userauth)(Authctxt *authctxt);
void (*cleanup)(Authctxt *authctxt);
int *enabled; /* flag in option struct that enables method */
int *batch_flag; /* flag in option struct that disables method */
};
int input_userauth_service_accept(int, u_int32_t, void *);
int input_userauth_ext_info(int, u_int32_t, void *);
int input_userauth_success(int, u_int32_t, void *);
int input_userauth_success_unexpected(int, u_int32_t, void *);
int input_userauth_failure(int, u_int32_t, void *);
int input_userauth_banner(int, u_int32_t, void *);
int input_userauth_error(int, u_int32_t, void *);
int input_userauth_info_req(int, u_int32_t, void *);
int input_userauth_pk_ok(int, u_int32_t, void *);
int input_userauth_passwd_changereq(int, u_int32_t, void *);
int userauth_none(Authctxt *);
int userauth_pubkey(Authctxt *);
int userauth_passwd(Authctxt *);
int userauth_kbdint(Authctxt *);
int userauth_hostbased(Authctxt *);
#ifdef GSSAPI
int userauth_gssapi(Authctxt *authctxt);
int input_gssapi_response(int type, u_int32_t, void *);
int input_gssapi_token(int type, u_int32_t, void *);
int input_gssapi_hash(int type, u_int32_t, void *);
int input_gssapi_error(int, u_int32_t, void *);
int input_gssapi_errtok(int, u_int32_t, void *);
#endif
void userauth(Authctxt *, char *);
static int sign_and_send_pubkey(Authctxt *, Identity *);
static void pubkey_prepare(Authctxt *);
static void pubkey_cleanup(Authctxt *);
static void pubkey_reset(Authctxt *);
static Key *load_identity_file(Identity *);
static Authmethod *authmethod_get(char *authlist);
static Authmethod *authmethod_lookup(const char *name);
static char *authmethods_get(void);
Authmethod authmethods[] = {
#ifdef GSSAPI
{"gssapi-with-mic",
userauth_gssapi,
NULL,
&options.gss_authentication,
NULL},
#endif
{"hostbased",
userauth_hostbased,
NULL,
&options.hostbased_authentication,
NULL},
{"publickey",
userauth_pubkey,
NULL,
&options.pubkey_authentication,
NULL},
{"keyboard-interactive",
userauth_kbdint,
NULL,
&options.kbd_interactive_authentication,
&options.batch_mode},
{"password",
userauth_passwd,
NULL,
&options.password_authentication,
&options.batch_mode},
{"none",
userauth_none,
NULL,
NULL,
NULL},
{NULL, NULL, NULL, NULL, NULL}
};
Authmethod nxauthmethods_pubkey[] = {
#ifdef GSSAPI
{"gssapi-with-mic",
userauth_gssapi,
NULL,
&options.gss_authentication,
NULL},
#endif
{"publickey",
userauth_pubkey,
&options.pubkey_authentication,
NULL},
{"none",
userauth_none,
NULL,
NULL},
{NULL, NULL, NULL, NULL}
};
Authmethod nxauthmethods_passwords[] = {
{"keyboard-interactive",
userauth_kbdint,
&options.kbd_interactive_authentication,
&options.batch_mode},
{"password",
userauth_passwd,
&options.password_authentication,
&options.batch_mode},
{"none",
userauth_none,
NULL,
NULL},
{NULL, NULL, NULL, NULL}
};
void
ssh_userauth2(const char *local_user, const char *server_user, char *host,
Sensitive *sensitive)
{
struct ssh *ssh = active_state;
Authctxt authctxt;
int r;
if (options.challenge_response_authentication)
options.kbd_interactive_authentication = 1;
if (options.preferred_authentications == NULL)
options.preferred_authentications = authmethods_get();
/* setup authentication context */
memset(&authctxt, 0, sizeof(authctxt));
pubkey_prepare(&authctxt);
authctxt.server_user = server_user;
authctxt.local_user = local_user;
authctxt.host = host;
authctxt.service = "ssh-connection"; /* service name */
authctxt.success = 0;
authctxt.method = authmethod_lookup("none");
authctxt.authlist = NULL;
authctxt.methoddata = NULL;
authctxt.sensitive = sensitive;
authctxt.active_ktype = authctxt.oktypes = authctxt.ktypes = NULL;
authctxt.info_req_seen = 0;
authctxt.agent_fd = -1;
if (authctxt.method == NULL)
fatal("ssh_userauth2: internal error: cannot send userauth none request");
if ((r = sshpkt_start(ssh, SSH2_MSG_SERVICE_REQUEST)) != 0 ||
(r = sshpkt_put_cstring(ssh, "ssh-userauth")) != 0 ||
(r = sshpkt_send(ssh)) != 0)
fatal("%s: %s", __func__, ssh_err(r));
ssh_dispatch_init(ssh, &input_userauth_error);
ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &input_userauth_ext_info);
ssh_dispatch_set(ssh, SSH2_MSG_SERVICE_ACCEPT, &input_userauth_service_accept);
ssh_dispatch_run(ssh, DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
pubkey_cleanup(&authctxt);
ssh_dispatch_range(ssh, SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL);
if (NxAuthOnlyModeEnabled) {
fprintf(stdout, "NX> 206 ssh-userauth2 successful: method %s\n", authctxt.method->name);
fflush(stdout);
cleanup_exit(0);
} else {
debug("Authentication succeeded (%s).", authctxt.method->name);
}
}
/* ARGSUSED */
int
input_userauth_service_accept(int type, u_int32_t seqnr, void *ctxt)
{
Authctxt *authctxt = ctxt;
struct ssh *ssh = active_state;
int r;
if (ssh_packet_remaining(ssh) > 0) {
char *reply;
if ((r = sshpkt_get_cstring(ssh, &reply, NULL)) != 0)
goto out;
debug2("service_accept: %s", reply);
free(reply);
} else {
debug2("buggy server: service_accept w/o service");
}
if ((r = sshpkt_get_end(ssh)) != 0)
goto out;
debug("SSH2_MSG_SERVICE_ACCEPT received");
/* initial userauth request */
userauth_none(authctxt);
ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &input_userauth_error);
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
r = 0;
out:
return r;
}
/* ARGSUSED */
int
input_userauth_ext_info(int type, u_int32_t seqnr, void *ctxt)
{
return kex_input_ext_info(type, seqnr, active_state);
}
void
userauth(Authctxt *authctxt, char *authlist)
{
if (authctxt->method != NULL && authctxt->method->cleanup != NULL)
authctxt->method->cleanup(authctxt);
free(authctxt->methoddata);
authctxt->methoddata = NULL;
if (authlist == NULL) {
authlist = authctxt->authlist;
} else {
free(authctxt->authlist);
authctxt->authlist = authlist;
}
for (;;) {
Authmethod *method = authmethod_get(authlist);
if (method == NULL) {
if (NxModeEnabled || NxAuthOnlyModeEnabled || NXServerMode || NxAdminModeEnabled) {
fprintf(stdout, "NX> 204 Authentication failed.\n");
fflush(stdout);
/*fatal_cleanup();*/
cleanup_exit(255);
}
else
fatal("Permission denied (%s).", authlist);
}
authctxt->method = method;
/* reset the per method handler */
dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN,
SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL);
/* and try new method */
if (method->userauth(authctxt) != 0) {
debug2("we sent a %s packet, wait for reply", method->name);
break;
} else {
debug2("we did not send a packet, disable method");
method->enabled = NULL;
}
}
}
/* ARGSUSED */
int
input_userauth_error(int type, u_int32_t seq, void *ctxt)
{
fatal("input_userauth_error: bad message during authentication: "
"type %d", type);
return 0;
}
/* ARGSUSED */
int
input_userauth_banner(int type, u_int32_t seq, void *ctxt)
{
char *msg, *lang;
u_int len;
debug3("%s", __func__);
msg = packet_get_string(&len);
lang = packet_get_string(NULL);
if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO)
fmprintf(stderr, "%s", msg);
free(msg);
free(lang);
return 0;
}
/* ARGSUSED */
int
input_userauth_success(int type, u_int32_t seq, void *ctxt)
{
Authctxt *authctxt = ctxt;
if (authctxt == NULL)
fatal("input_userauth_success: no authentication context");
free(authctxt->authlist);
authctxt->authlist = NULL;
if (authctxt->method != NULL && authctxt->method->cleanup != NULL)
authctxt->method->cleanup(authctxt);
free(authctxt->methoddata);
authctxt->methoddata = NULL;
authctxt->success = 1; /* break out */
return 0;
}
int
input_userauth_success_unexpected(int type, u_int32_t seq, void *ctxt)
{
Authctxt *authctxt = ctxt;
if (authctxt == NULL)
fatal("%s: no authentication context", __func__);
fatal("Unexpected authentication success during %s.",
authctxt->method->name);
return 0;
}
/* ARGSUSED */
int
input_userauth_failure(int type, u_int32_t seq, void *ctxt)
{
Authctxt *authctxt = ctxt;
char *authlist = NULL;
int partial;
if (authctxt == NULL)
fatal("input_userauth_failure: no authentication context");
authlist = packet_get_string(NULL);
partial = packet_get_char();
packet_check_eom();
if (partial != 0) {
verbose("Authenticated with partial success.");
/* reset state */
pubkey_reset(authctxt);
}
debug("Authentications that can continue: %s", authlist);
userauth(authctxt, authlist);
return 0;
}
/* ARGSUSED */
int
input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
{
Authctxt *authctxt = ctxt;
Key *key = NULL;
Identity *id = NULL;
Buffer b;
int pktype, sent = 0;
u_int alen, blen;
char *pkalg, *fp;
u_char *pkblob;
if (authctxt == NULL)
fatal("input_userauth_pk_ok: no authentication context");
if (datafellows & SSH_BUG_PKOK) {
/* this is similar to SSH_BUG_PKAUTH */
debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
pkblob = packet_get_string(&blen);
buffer_init(&b);
buffer_append(&b, pkblob, blen);
pkalg = buffer_get_string(&b, &alen);
buffer_free(&b);
} else {
pkalg = packet_get_string(&alen);
pkblob = packet_get_string(&blen);
}
packet_check_eom();
debug("Server accepts key: pkalg %s blen %u", pkalg, blen);
if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
debug("unknown pkalg %s", pkalg);
goto done;
}
if ((key = key_from_blob(pkblob, blen)) == NULL) {
debug("no key from blob. pkalg %s", pkalg);
goto done;
}
if (key->type != pktype) {
error("input_userauth_pk_ok: type mismatch "
"for decoded key (received %d, expected %d)",
key->type, pktype);
goto done;
}
if ((fp = sshkey_fingerprint(key, options.fingerprint_hash,
SSH_FP_DEFAULT)) == NULL)
goto done;
debug2("input_userauth_pk_ok: fp %s", fp);
free(fp);
/*
* search keys in the reverse order, because last candidate has been
* moved to the end of the queue. this also avoids confusion by
* duplicate keys
*/
TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) {
if (key_equal(key, id->key)) {
sent = sign_and_send_pubkey(authctxt, id);
break;
}
}
done:
if (key != NULL)
key_free(key);
free(pkalg);
free(pkblob);
/* try another method if we did not send a packet */
if (sent == 0)
userauth(authctxt, NULL);
return 0;
}
#ifdef GSSAPI
int
userauth_gssapi(Authctxt *authctxt)
{
Gssctxt *gssctxt = NULL;
static gss_OID_set gss_supported = NULL;
static u_int mech = 0;
OM_uint32 min;
int ok = 0;
/* Try one GSSAPI method at a time, rather than sending them all at
* once. */
if (gss_supported == NULL)
gss_indicate_mechs(&min, &gss_supported);
/* Check to see if the mechanism is usable before we offer it */
while (mech < gss_supported->count && !ok) {
/* My DER encoding requires length<128 */
if (gss_supported->elements[mech].length < 128 &&
ssh_gssapi_check_mechanism(&gssctxt,
&gss_supported->elements[mech], authctxt->host)) {
ok = 1; /* Mechanism works */
} else {
mech++;
}
}
if (!ok)
return 0;
authctxt->methoddata=(void *)gssctxt;
packet_start(SSH2_MSG_USERAUTH_REQUEST);
packet_put_cstring(authctxt->server_user);
packet_put_cstring(authctxt->service);
packet_put_cstring(authctxt->method->name);
packet_put_int(1);
packet_put_int((gss_supported->elements[mech].length) + 2);
packet_put_char(SSH_GSS_OIDTYPE);
packet_put_char(gss_supported->elements[mech].length);
packet_put_raw(gss_supported->elements[mech].elements,
gss_supported->elements[mech].length);
packet_send();
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response);
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error);
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
mech++; /* Move along to next candidate */
return 1;
}
static OM_uint32
process_gssapi_token(void *ctxt, gss_buffer_t recv_tok)
{
Authctxt *authctxt = ctxt;
Gssctxt *gssctxt = authctxt->methoddata;
gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
gss_buffer_desc gssbuf;
OM_uint32 status, ms, flags;
Buffer b;
status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
recv_tok, &send_tok, &flags);
if (send_tok.length > 0) {
if (GSS_ERROR(status))
packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
else
packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
packet_put_string(send_tok.value, send_tok.length);
packet_send();
gss_release_buffer(&ms, &send_tok);
}
if (status == GSS_S_COMPLETE) {
/* send either complete or MIC, depending on mechanism */
if (!(flags & GSS_C_INTEG_FLAG)) {
packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
packet_send();
} else {
ssh_gssapi_buildmic(&b, authctxt->server_user,
authctxt->service, "gssapi-with-mic");
gssbuf.value = buffer_ptr(&b);
gssbuf.length = buffer_len(&b);
status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic);
if (!GSS_ERROR(status)) {
packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC);
packet_put_string(mic.value, mic.length);
packet_send();
}
buffer_free(&b);
gss_release_buffer(&ms, &mic);
}
}
return status;
}
/* ARGSUSED */
int
input_gssapi_response(int type, u_int32_t plen, void *ctxt)
{
Authctxt *authctxt = ctxt;
Gssctxt *gssctxt;
int oidlen;
char *oidv;
if (authctxt == NULL)
fatal("input_gssapi_response: no authentication context");
gssctxt = authctxt->methoddata;
/* Setup our OID */
oidv = packet_get_string(&oidlen);
if (oidlen <= 2 ||
oidv[0] != SSH_GSS_OIDTYPE ||
oidv[1] != oidlen - 2) {
free(oidv);
debug("Badly encoded mechanism OID received");
userauth(authctxt, NULL);
return 0;
}
if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2))
fatal("Server returned different OID than expected");
packet_check_eom();
free(oidv);
if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) {
/* Start again with next method on list */
debug("Trying to start again");
userauth(authctxt, NULL);
return 0;
}
return 0;
}
/* ARGSUSED */
int
input_gssapi_token(int type, u_int32_t plen, void *ctxt)
{
Authctxt *authctxt = ctxt;
gss_buffer_desc recv_tok;
OM_uint32 status;
u_int slen;
if (authctxt == NULL)
fatal("input_gssapi_response: no authentication context");
recv_tok.value = packet_get_string(&slen);
recv_tok.length = slen; /* safe typecast */
packet_check_eom();
status = process_gssapi_token(ctxt, &recv_tok);
free(recv_tok.value);
if (GSS_ERROR(status)) {
/* Start again with the next method in the list */
userauth(authctxt, NULL);
return 0;
}
return 0;
}
/* ARGSUSED */
int
input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
{
Authctxt *authctxt = ctxt;
Gssctxt *gssctxt;
gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
gss_buffer_desc recv_tok;
OM_uint32 ms;
u_int len;
if (authctxt == NULL)
fatal("input_gssapi_response: no authentication context");
gssctxt = authctxt->methoddata;
recv_tok.value = packet_get_string(&len);
recv_tok.length = len;
packet_check_eom();
/* Stick it into GSSAPI and see what it says */
(void)ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
&recv_tok, &send_tok, NULL);
free(recv_tok.value);
gss_release_buffer(&ms, &send_tok);
/* Server will be returning a failed packet after this one */
return 0;
}
/* ARGSUSED */
int
input_gssapi_error(int type, u_int32_t plen, void *ctxt)
{
char *msg;
char *lang;
/* maj */(void)packet_get_int();
/* min */(void)packet_get_int();
msg=packet_get_string(NULL);
lang=packet_get_string(NULL);
packet_check_eom();
debug("Server GSSAPI Error:\n%s", msg);
free(msg);
free(lang);
return 0;
}
#endif /* GSSAPI */
int
userauth_none(Authctxt *authctxt)
{
/* initial userauth request */
packet_start(SSH2_MSG_USERAUTH_REQUEST);
packet_put_cstring(authctxt->server_user);
packet_put_cstring(authctxt->service);
packet_put_cstring(authctxt->method->name);
packet_send();
return 1;
}
int
userauth_passwd(Authctxt *authctxt)
{
static int attempt = 0;
char prompt[150];
char *password;
const char *host = options.host_key_alias ? options.host_key_alias :
authctxt->host;
if ((NxAuthOnlyModeEnabled && attempt >= 1) || (attempt++ >= options.number_of_password_prompts))
return 0;
if (attempt != 1)
error("Permission denied, please try again.");
if (NxAuthOnlyModeEnabled || NxModeEnabled || NXStdinPassEnabled) {
snprintf(prompt, sizeof(prompt), "NX> 205 %.30s@%.128s's password: ",
authctxt->server_user, authctxt->host);
} else {
snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
authctxt->server_user, host);
}
password = read_passphrase(prompt, 0);
packet_start(SSH2_MSG_USERAUTH_REQUEST);
packet_put_cstring(authctxt->server_user);
packet_put_cstring(authctxt->service);
packet_put_cstring(authctxt->method->name);
packet_put_char(0);
packet_put_cstring(password);
explicit_bzero(password, strlen(password));
free(password);
packet_add_padding(64);
packet_send();
dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
&input_userauth_passwd_changereq);
return 1;
}