C++ packet_check_eom函数代码示例

void
input_userauth_info_response_pam(int type, u_int32_t seqnr, void *ctxt)
{
	Authctxt *authctxt = ctxt;
	unsigned int nresp = 0, rlen = 0, i = 0;
	char *resp;

	if (authctxt == NULL)
		fatal("input_userauth_info_response_pam: no authentication context");

	nresp = packet_get_int();	/* Number of responses. */
	debug("got %d responses", nresp);


	if (nresp != context_pam2.num_expected)
		fatal("%s: Received incorrect number of responses "
		    "(expected %d, received %u)", __func__, 
		    context_pam2.num_expected, nresp);

	if (nresp > 100)
		fatal("%s: too many replies", __func__);

	for (i = 0; i < nresp; i++) {
		int j = context_pam2.prompts[i];

		resp = packet_get_string(&rlen);
		context_pam2.responses[j].resp_retcode = PAM_SUCCESS;
		context_pam2.responses[j].resp = resp;
		context_pam2.num_received++;
	}

	context_pam2.finished = 1;

	packet_check_eom();
}

/* 
 * The 'gssapi_keyex' userauth mechanism.
 */
static int
userauth_gsskeyex(Authctxt *authctxt)
{
	int authenticated = 0;
	Buffer b;
	gss_buffer_desc mic, gssbuf;
	u_int len;

	mic.value = packet_get_string(&len);
	mic.length = len;

	packet_check_eom();

	ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
	    "gssapi-keyex");

	gssbuf.value = buffer_ptr(&b);
	gssbuf.length = buffer_len(&b);

	/* gss_kex_context is NULL with privsep, so we can't check it here */
	if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gss_kex_context, 
	    &gssbuf, &mic))))
		authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user,
		    authctxt->pw));
	
	buffer_free(&b);
	free(mic.value);

	return (authenticated);
}

/*
 * Performs authentication of an incoming connection.  Session key has already
 * been exchanged and encryption is enabled.
 */
Authctxt *
do_authentication(void)
{
	Authctxt *authctxt;
	u_int ulen;
	char *user, *style = NULL;

	/* Get the name of the user that we wish to log in as. */
	packet_read_expect(SSH_CMSG_USER);

	/* Get the user name. */
	user = packet_get_string(&ulen);
	packet_check_eom();

	if ((style = strchr(user, ':')) != NULL)
		*style++ = '\0';

	authctxt = authctxt_new();
	authctxt->user = user;
	authctxt->style = style;

	/* Verify that the user is a valid user. */
	if ((authctxt->pw = PRIVSEP(getpwnamallow(user))) != NULL)
		authctxt->valid = 1;
	else {
		debug("do_authentication: illegal user %s", user);
		authctxt->pw = fakepw();
	}

	setproctitle("%s%s", authctxt->pw ? user : "unknown",
	    use_privsep ? " [net]" : "");

#ifdef USE_PAM
	if (options.use_pam)
		PRIVSEP(start_pam(user));
#endif

	/*
	 * If we are not running as root, the user must have the same uid as
	 * the server. (Unless you are running Windows)
	 */
#ifndef HAVE_CYGWIN
	if (!use_privsep && getuid() != 0 && authctxt->pw &&
	    authctxt->pw->pw_uid != getuid())
		packet_disconnect("Cannot change user when server not running as root.");
#endif

	/*
	 * Loop until the user has been authenticated or the connection is
	 * closed, do_authloop() returns only if authentication is successful
	 */
	do_authloop(authctxt);

	/* The user has been authenticated and accepted. */
	packet_start(SSH_SMSG_SUCCESS);
	packet_send();
	packet_write_wait();

	return (authctxt);
}

static Channel *
server_request_direct_tcpip(void)
{
	Channel *c;
	char *target, *originator;
	u_short target_port, originator_port;

	target = packet_get_string(NULL);
	target_port = packet_get_int();
	originator = packet_get_string(NULL);
	originator_port = packet_get_int();
	packet_check_eom();

	debug("server_request_direct_tcpip: originator %s port %d, target %s "
	    "port %d", originator, originator_port, target, target_port);

	/* XXX check permission */
	c = channel_connect_to(target, target_port,
	    "direct-tcpip", "direct-tcpip");

	xfree(originator);
	xfree(target);

	return c;
}

void
ssh_userauth2(const char *local_user, const char *server_user, char *host,
    Sensitive *sensitive)
{
	Authctxt authctxt;
	int type;

	if (options.challenge_response_authentication)
		options.kbd_interactive_authentication = 1;

	packet_start(SSH2_MSG_SERVICE_REQUEST);
	packet_put_cstring("ssh-userauth");
	packet_send();
	debug("SSH2_MSG_SERVICE_REQUEST sent");
	packet_write_wait();
	type = packet_read();
	if (type != SSH2_MSG_SERVICE_ACCEPT)
		fatal("Server denied authentication request: %d", type);
	if (packet_remaining() > 0) {
		char *reply = packet_get_string(NULL);
		debug2("service_accept: %s", reply);
		xfree(reply);
	} else {
		debug2("buggy server: service_accept w/o service");
	}
	packet_check_eom();
	debug("SSH2_MSG_SERVICE_ACCEPT received");

	if (options.preferred_authentications == NULL)
		options.preferred_authentications = authmethods_get();

	/* setup authentication context */
	memset(&authctxt, 0, sizeof(authctxt));
	authctxt.agent = ssh_get_authentication_connection();
	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.sensitive = sensitive;
	authctxt.info_req_seen = 0;
	if (authctxt.method == NULL)
		fatal("ssh_userauth2: internal error: cannot send userauth none request");

	/* initial userauth request */
	userauth_none(&authctxt);

	dispatch_init(&input_userauth_error);
	dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
	dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
	dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
	dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt);	/* loop until success */

	if (authctxt.agent != NULL)
		ssh_close_authentication_connection(authctxt.agent);

	debug("Authentication succeeded (%s).", authctxt.method->name);
}

int
auth_rsa_challenge_dialog(Key *key)
{
	BIGNUM *challenge, *encrypted_challenge;
	u_char response[16];
	int i, success;

	if ((encrypted_challenge = BN_new()) == NULL)
		fatal("auth_rsa_challenge_dialog: BN_new() failed");

	challenge = PRIVSEP(auth_rsa_generate_challenge(key));

	/* Encrypt the challenge with the public key. */
	rsa_public_encrypt(encrypted_challenge, challenge, key->rsa);

	/* Send the encrypted challenge to the client. */
	packet_start(SSH_SMSG_AUTH_RSA_CHALLENGE);
	packet_put_bignum(encrypted_challenge);
	packet_send();
	BN_clear_free(encrypted_challenge);
	packet_write_wait();

	/* Wait for a response. */
	packet_read_expect(SSH_CMSG_AUTH_RSA_RESPONSE);
	for (i = 0; i < 16; i++)
		response[i] = (u_char)packet_get_char();
	packet_check_eom();

	success = PRIVSEP(auth_rsa_verify_response(key, challenge, response));
	BN_clear_free(challenge);
	return (success);
}

static int
input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
{
	Authctxt *authctxt = ctxt;
	int authenticated;

	if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
		fatal("No authentication or GSSAPI context");

	/*
	 * We don't need to check the status, because we're only enabled in
	 * the dispatcher once the exchange is complete
	 */

	packet_check_eom();

	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user,
	    authctxt->pw));

	authctxt->postponed = 0;
	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
	userauth_finish(authctxt, authenticated, "gssapi-with-mic", NULL);
	return 0;
}

static int
server_input_channel_req(int type, u_int32_t seq, void *ctxt)
{
	Channel *c;
	int id, reply, success = 0;
	char *rtype;

	id = packet_get_int();
	rtype = packet_get_string(NULL);
	reply = packet_get_char();

	debug("server_input_channel_req: channel %d request %s reply %d",
	    id, rtype, reply);

	if ((c = channel_lookup(id)) == NULL)
		packet_disconnect("server_input_channel_req: "
		    "unknown channel %d", id);
	if (!strcmp(rtype, "[email protected]")) {
		packet_check_eom();
		chan_rcvd_eow(c);
	} else if ((c->type == SSH_CHANNEL_LARVAL ||
	    c->type == SSH_CHANNEL_OPEN) && strcmp(c->ctype, "session") == 0)
		success = session_input_channel_req(c, rtype);
	if (reply && !(c->flags & CHAN_CLOSE_SENT)) {
		packet_start(success ?
		    SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
		packet_put_int(c->remote_id);
		packet_send();
	}
	free(rtype);
	return 0;
}

static int
userauth_kbdint(Authctxt *authctxt)
{
	int authenticated = 0;
	char *lang, *devs;

	lang = packet_get_string(NULL);
	devs = packet_get_string(NULL);
	packet_check_eom();

	debug("keyboard-interactive devs %s", devs);

	if (options.challenge_response_authentication)
		authenticated = auth2_challenge(authctxt, devs);

#ifdef USE_PAM
	if (authenticated == 0 && options.pam_authentication_via_kbd_int)
		authenticated = auth2_pam(authctxt);
#endif
	xfree(devs);
	xfree(lang);
#ifdef HAVE_CYGWIN
	if (check_nt_auth(0, authctxt->pw) == 0)
		return(0);
#endif
	return authenticated;
}

static Channel *
server_request_direct_tcpip(void)
{
	Channel *c = NULL;
	char *target, *originator;
	u_short target_port, originator_port;

	target = packet_get_string(NULL);
	target_port = packet_get_int();
	originator = packet_get_string(NULL);
	originator_port = packet_get_int();
	packet_check_eom();

	debug("server_request_direct_tcpip: originator %s port %d, target %s "
	    "port %d", originator, originator_port, target, target_port);

	/* XXX fine grained permissions */
	if ((options.allow_tcp_forwarding & FORWARD_LOCAL) != 0 &&
	    !no_port_forwarding_flag) {
		c = channel_connect_to_port(target, target_port,
		    "direct-tcpip", "direct-tcpip");
	} else {
		logit("refused local port forward: "
		    "originator %s port %d, target %s port %d",
		    originator, originator_port, target, target_port);
	}

	free(originator);
	free(target);

	return c;
}

/*ARGSUSED*/
static void
input_service_request(int type, u_int32_t seq, void *ctxt)
{
    Authctxt *authctxt = ctxt;
    u_int len;
    int acceptit = 0;
    char *service = packet_get_cstring(&len);
    packet_check_eom();

    if (authctxt == NULL)
        fatal("input_service_request: no authctxt");

    if (strcmp(service, "ssh-userauth") == 0) {
        if (!authctxt->success) {
            acceptit = 1;
            /* now we can handle user-auth requests */
            dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
        }
    }
    /* XXX all other service requests are denied */

    if (acceptit) {
        packet_start(SSH2_MSG_SERVICE_ACCEPT);
        packet_put_cstring(service);
        packet_send();
        packet_write_wait();
    } else {
        debug("bad service request %s", service);
        packet_disconnect("bad service request %s", service);
    }
    free(service);
}

static 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 maj_status;
	u_int len;

	if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
		fatal("No authentication or GSSAPI context");

	gssctxt = authctxt->methoddata;
	recv_tok.value = packet_get_string(&len);
	recv_tok.length = len;

	packet_check_eom();

	/* Push the error token into GSSAPI to see what it says */
	maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
	    &send_tok, NULL));

	free(recv_tok.value);

	/* We can't return anything to the client, even if we wanted to */
	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);

	/* The client will have already moved on to the next auth */

	gss_release_buffer(&maj_status, &send_tok);
	return 0;
}

/* ARGSUSED */
void
kex_input_kexinit(int type, u_int32_t seq, void *ctxt)
{
	char *ptr;
	u_int i, dlen;
	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++)
		free(packet_get_string(NULL));
	/*
	 * XXX RFC4253 sec 7: "each side MAY guess" - currently no supported
	 * KEX method has the server move first, but a server might be using
	 * a custom method or one that we otherwise don't support. We should
	 * be prepared to remember first_kex_follows here so we can eat a
	 * packet later.
	 * XXX2 - RFC4253 is kind of ambiguous on what first_kex_follows means
	 * for cases where the server *doesn't* go first. I guess we should
	 * ignore it when it is set for these cases, which is what we do now.
	 */
	(void) packet_get_char();	/* first_kex_follows */
	(void) packet_get_int();	/* reserved */
	packet_check_eom();

	kex_kexinit_finish(kex);
}

static int
userauth_passwd(Authctxt *authctxt)
{
	char *password, *newpass;
	int authenticated = 0;
	int change;
	u_int len, newlen;

	change = packet_get_char();
	password = packet_get_string(&len);
	if (change) {
		/* discard new password from packet */
		newpass = packet_get_string(&newlen);
		memset(newpass, 0, newlen);
		xfree(newpass);
	}
	packet_check_eom();

	if (change)
		logit("password change not supported");
	else if (PRIVSEP(auth_password(authctxt, password)) == 1)
		authenticated = 1;
#ifdef HAVE_CYGWIN
	if (check_nt_auth(1, authctxt->pw) == 0)
		authenticated = 0;
#endif
	memset(password, 0, len);
	xfree(password);
	return authenticated;
}

/*ARGSUSED*/
static int
auth1_process_password(Authctxt *authctxt, char *info, size_t infolen)
{
	int authenticated = 0;
	char *password;
	u_int dlen;

	/*
	 * Read user password.  It is in plain text, but was
	 * transmitted over the encrypted channel so it is
	 * not visible to an outside observer.
	 */
	password = packet_get_string(&dlen);
	packet_check_eom();

	/* Try authentication with the password. */
#ifndef ANDROID
	authenticated = PRIVSEP(auth_password(authctxt, password));

#else
	/* no password authentication in android */
	authenticated = 0;
#endif

	memset(password, 0, dlen);
	xfree(password);

	return (authenticated);
}