*    channels.
 */

#define SSH1_BUFFER_LIMIT 32768
#define SSH_MAX_BACKLOG 32768
#define OUR_V2_WINSIZE 16384
#define OUR_V2_MAXPKT 0x4000UL

/* Maximum length of passwords/passphrases (arbitrary) */
#define SSH_MAX_PASSWORD_LEN 100

const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };

const static struct ssh_mac *macs[] = {
    &ssh_hmac_sha1, &ssh_hmac_sha1_96, &ssh_hmac_md5
};
const static struct ssh_mac *buggymacs[] = {

     * scp1 if that fails. This variable is the means by which
     * scp.c can reach into the SSH code and find out which one it
     * got.
     */
    int fallback_cmd;

    bufchain banner;	/* accumulates banners during do_ssh2_authconn */








    int pkt_ctx;

    void *x11auth;

    int version;
    int v1_throttle_count;

     */
    {
	unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
	assert(NULL == find234(ssh->channels, &i, ssh_channelfind));
    }
    return low + 1 + CHANNEL_NUMBER_OFFSET;
}

static void c_write_stderr(int trusted, const char *buf, int len)
{
    int i;
    for (i = 0; i < len; i++)
	if (buf[i] != '\r' && (trusted || buf[i] & 0x60))
	    fputc(buf[i], stderr);
}

static void c_write(Ssh ssh, const char *buf, int len)
{
    if (flags & FLAG_STDERR)



	c_write_stderr(1, buf, len);
    else

	from_backend(ssh->frontend, 1, buf, len);
}

static void c_write_untrusted(Ssh ssh, const char *buf, int len)
{


    if (flags & FLAG_STDERR)
	c_write_stderr(0, buf, len);
    else
	from_backend_untrusted(ssh->frontend, buf, len);

}

static void c_write_str(Ssh ssh, const char *buf)
{
    c_write(ssh, buf, strlen(buf));
}

	  case CHAN_SOCKDATA:
	    pfd_override_throttle(c->u.pfd.s, enable);
	    break;
	}
    }
}









































































static void ssh_agent_callback(void *sshv, void *reply, int replylen)
{
    Ssh ssh = (Ssh) sshv;

    ssh->agent_response = reply;
    ssh->agent_response_len = replylen;

	int tried_publickey, tried_agent;
	int tis_auth_refused, ccard_auth_refused;
	unsigned char session_id[16];
	int cipher_type;
	char username[100];
	void *publickey_blob;
	int publickey_bloblen;

	char *publickey_comment;
	int publickey_encrypted;
	prompts_t *cur_prompt;
	char c;
	int pwpkt_type;
	unsigned char request[5], *response, *p;
	int responselen;
	int keyi, nkeys;
	int authed;
	struct RSAKey key;

    if (pktin->type != SSH1_SMSG_SUCCESS) {
	bombout(("Encryption not successfully enabled"));
	crStop(0);
    }

    logevent("Successfully started encryption");

    fflush(stdout); /* FIXME eh? */
    {
	if (!*ssh->cfg.username) {
	    int ret; /* need not be kept over crReturn */
	    s->cur_prompt = new_prompts(ssh->frontend);
	    s->cur_prompt->to_server = TRUE;
	    s->cur_prompt->name = dupstr("SSH login name");
	    add_prompt(s->cur_prompt, dupstr("login as: "), TRUE,
		       lenof(s->username)); 
	    ret = get_userpass_input(s->cur_prompt, NULL, 0);
	    while (ret < 0) {
		ssh->send_ok = 1;
		crWaitUntil(!pktin);
		ret = get_userpass_input(s->cur_prompt, in, inlen);
		ssh->send_ok = 0;
	    }
	    if (!ret) {
		/*
		 * Failed to get a username. Terminate.

		 */
		free_prompts(s->cur_prompt);
		ssh_disconnect(ssh, "No username provided", NULL, 0, TRUE);
		crStop(0);
	    }




	    memcpy(s->username, s->cur_prompt->prompts[0]->result,
		   lenof(s->username));




	    free_prompts(s->cur_prompt);



	} else {
	    strncpy(s->username, ssh->cfg.username, sizeof(s->username));
	    s->username[sizeof(s->username)-1] = '\0';
	}

	send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END);
	{

	    char *userlog = dupprintf("Sent username \"%s\"", s->username);
	    logevent(userlog);
	    if (flags & FLAG_INTERACTIVE &&
		(!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
		c_write_str(ssh, userlog);
		c_write_str(ssh, "\r\n");
	    }
	    sfree(userlog);
	}
    }

    crWaitUntil(pktin);

    if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
	/* We must not attempt PK auth. Pretend we've already tried it. */
	s->tried_publickey = s->tried_agent = 1;
    } else {
	s->tried_publickey = s->tried_agent = 0;
    }
    s->tis_auth_refused = s->ccard_auth_refused = 0;
    /*
     * Load the public half of any configured keyfile for later use.
     */
    if (!filename_is_null(ssh->cfg.keyfile)) {
	int keytype;
	logeventf(ssh, "Reading private key file \"%.150s\"",
		  filename_to_str(&ssh->cfg.keyfile));
	keytype = key_type(&ssh->cfg.keyfile);
	if (keytype == SSH_KEYTYPE_SSH1) {
	    const char *error;
	    if (rsakey_pubblob(&ssh->cfg.keyfile,
			       &s->publickey_blob, &s->publickey_bloblen,
			       &s->publickey_comment, &error)) {
		s->publickey_encrypted = rsakey_encrypted(&ssh->cfg.keyfile,
							  NULL);
	    } else {
		char *msgbuf;
		logeventf(ssh, "Unable to load private key (%s)", error);
		msgbuf = dupprintf("Unable to load private key file "
				   "\"%.150s\" (%s)\r\n",
				   filename_to_str(&ssh->cfg.keyfile),
				   error);
		c_write_str(ssh, msgbuf);
		sfree(msgbuf);
		s->publickey_blob = NULL;
	    }
	} else {
	    char *msgbuf;
	    logeventf(ssh, "Unable to use this key file (%s)",
		      key_type_to_str(keytype));
	    msgbuf = dupprintf("Unable to use key file \"%.150s\""
			       " (%s)\r\n",
			       filename_to_str(&ssh->cfg.keyfile),
			       key_type_to_str(keytype));
	    c_write_str(ssh, msgbuf);
	    sfree(msgbuf);
	    s->publickey_blob = NULL;
	}
    } else
	s->publickey_blob = NULL;

    while (pktin->type == SSH1_SMSG_FAILURE) {
	s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;

	if (agent_exists() && !s->tried_agent) {

			break;
		}
		sfree(s->response);
	    }
	    if (s->authed)
		break;
	}
	if (s->publickey_blob && !s->tried_publickey) {
	    /*
	     * Try public key authentication with the specified
	     * key file.
	     */
	    int got_passphrase; /* need not be kept over crReturn */
	    if (flags & FLAG_VERBOSE)
		c_write_str(ssh, "Trying public key authentication.\r\n");
	    logeventf(ssh, "Trying public key \"%s\"",
		      filename_to_str(&ssh->cfg.keyfile));
	    s->tried_publickey = 1;
	    got_passphrase = FALSE;
	    while (!got_passphrase) {
		/*
		 * Get a passphrase, if necessary.
		 */
		char *passphrase = NULL;    /* only written after crReturn */
		const char *error;
		if (!s->publickey_encrypted) {
		    if (flags & FLAG_VERBOSE)
			c_write_str(ssh, "No passphrase required.\r\n");
		    passphrase = NULL;
		} else {
		    int ret; /* need not be kept over crReturn */
		    s->cur_prompt = new_prompts(ssh->frontend);
		    s->cur_prompt->to_server = FALSE;
		    s->cur_prompt->name = dupstr("SSH key passphrase");
		    add_prompt(s->cur_prompt,
			       dupprintf("Passphrase for key \"%.100s\": ",
					 s->publickey_comment),
			       FALSE, SSH_MAX_PASSWORD_LEN);
		    ret = get_userpass_input(s->cur_prompt, NULL, 0);
		    while (ret < 0) {
			ssh->send_ok = 1;
			crWaitUntil(!pktin);
			ret = get_userpass_input(s->cur_prompt, in, inlen);
			ssh->send_ok = 0;
		    }
		    if (!ret) {
			/* Failed to get a passphrase. Terminate. */
			free_prompts(s->cur_prompt);
			ssh_disconnect(ssh, NULL, "Unable to authenticate",
				       0, TRUE);
			crStop(0);
		    }
		    passphrase = dupstr(s->cur_prompt->prompts[0]->result);
		    free_prompts(s->cur_prompt);
		}
		/*
		 * Try decrypting key with passphrase.
		 */
		ret = loadrsakey(&ssh->cfg.keyfile, &s->key, passphrase,
				 &error);
		if (passphrase) {
		    memset(passphrase, 0, strlen(passphrase));
		    sfree(passphrase);
		}
		if (ret == 1) {
		    /* Correct passphrase. */
		    got_passphrase = TRUE;
		} else if (ret == 0) {
		    c_write_str(ssh, "Couldn't load private key from ");
		    c_write_str(ssh, filename_to_str(&ssh->cfg.keyfile));
		    c_write_str(ssh, " (");
		    c_write_str(ssh, error);
		    c_write_str(ssh, ").\r\n");
		    got_passphrase = FALSE;
		    break;	       /* go and try something else */
		} else if (ret == -1) {
		    c_write_str(ssh, "Wrong passphrase.\r\n"); /* FIXME */
		    s->tried_publickey = 0;
		    got_passphrase = FALSE;
		    /* and try again */
		}
	    }

	    if (got_passphrase) {

		/*
		 * Send a public key attempt.
		 */
		send_packet(ssh, SSH1_CMSG_AUTH_RSA,
			    PKT_BIGNUM, s->key.modulus, PKT_END);

		crWaitUntil(pktin);
		if (pktin->type == SSH1_SMSG_FAILURE) {
		    c_write_str(ssh, "Server refused our public key.\r\n");
		    continue;	       /* go and try password */
		}
		if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
		    bombout(("Bizarre response to offer of public key"));
		    crStop(0);
		}

		{
		    int i;
		    unsigned char buffer[32];
		    Bignum challenge, response;

		    if ((challenge = ssh1_pkt_getmp(pktin)) == NULL) {
			bombout(("Server's RSA challenge was badly formatted"));
			crStop(0);
		    }
		    response = rsadecrypt(challenge, &s->key);
		    freebn(s->key.private_exponent);/* burn the evidence */

		    for (i = 0; i < 32; i++) {
			buffer[i] = bignum_byte(response, 31 - i);
		    }

		    MD5Init(&md5c);
		    MD5Update(&md5c, buffer, 32);
		    MD5Update(&md5c, s->session_id, 16);
		    MD5Final(buffer, &md5c);

		    send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
				PKT_DATA, buffer, 16, PKT_END);

		    freebn(challenge);
		    freebn(response);
		}

		crWaitUntil(pktin);
		if (pktin->type == SSH1_SMSG_FAILURE) {
		    if (flags & FLAG_VERBOSE)
			c_write_str(ssh, "Failed to authenticate with"
				    " our public key.\r\n");
		    continue;	       /* go and try password */
		} else if (pktin->type != SSH1_SMSG_SUCCESS) {
		    bombout(("Bizarre response to RSA authentication response"));
		    crStop(0);
		}

		break;		       /* we're through! */
	    }

	}

	/*
	 * Otherwise, try various forms of password-like authentication.
	 */
	s->cur_prompt = new_prompts(ssh->frontend);

	if (ssh->cfg.try_tis_auth &&
	    (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
	    !s->tis_auth_refused) {
	    s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
	    logevent("Requested TIS authentication");
	    send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
	    crWaitUntil(pktin);
	    if (pktin->type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
		logevent("TIS authentication declined");
		if (flags & FLAG_INTERACTIVE)
		    c_write_str(ssh, "TIS authentication refused.\r\n");
		s->tis_auth_refused = 1;
		continue;
	    } else {
		char *challenge;
		int challengelen;
		char *instr_suf, *prompt;

		ssh_pkt_getstring(pktin, &challenge, &challengelen);
		if (!challenge) {
		    bombout(("TIS challenge packet was badly formed"));
		    crStop(0);
		}

		logevent("Received TIS challenge");
		s->cur_prompt->to_server = TRUE;

		s->cur_prompt->name = dupstr("SSH TIS authentication");
		/* Prompt heuristic comes from OpenSSH */
		if (memchr(challenge, '\n', challengelen)) {
		    instr_suf = dupstr("");
		    prompt = dupprintf("%.*s", challengelen, challenge);
		} else {
		    instr_suf = dupprintf("%.*s", challengelen, challenge);
		    prompt = dupstr("Response: ");
		}
		s->cur_prompt->instruction =
		    dupprintf("Using TIS authentication.%s%s",
			      (*instr_suf) ? "\n" : "",
			      instr_suf);
		s->cur_prompt->instr_reqd = TRUE;
		add_prompt(s->cur_prompt, prompt, FALSE, SSH_MAX_PASSWORD_LEN);
		sfree(instr_suf);
	    }
	}
	if (ssh->cfg.try_tis_auth &&
	    (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
	    !s->ccard_auth_refused) {
	    s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
	    logevent("Requested CryptoCard authentication");
	    send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
	    crWaitUntil(pktin);
	    if (pktin->type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
		logevent("CryptoCard authentication declined");
		c_write_str(ssh, "CryptoCard authentication refused.\r\n");
		s->ccard_auth_refused = 1;
		continue;
	    } else {
		char *challenge;
		int challengelen;
		char *instr_suf, *prompt;

		ssh_pkt_getstring(pktin, &challenge, &challengelen);
		if (!challenge) {
		    bombout(("CryptoCard challenge packet was badly formed"));
		    crStop(0);
		}

		logevent("Received CryptoCard challenge");
		s->cur_prompt->to_server = TRUE;
		s->cur_prompt->name = dupstr("SSH CryptoCard authentication");
		s->cur_prompt->name_reqd = FALSE;
		/* Prompt heuristic comes from OpenSSH */
		if (memchr(challenge, '\n', challengelen)) {
		    instr_suf = dupstr("");
		    prompt = dupprintf("%.*s", challengelen, challenge);
		} else {
		    instr_suf = dupprintf("%.*s", challengelen, challenge);
		    prompt = dupstr("Response: ");
		}
		s->cur_prompt->instruction =
		    dupprintf("Using CryptoCard authentication.%s%s",
			      (*instr_suf) ? "\n" : "",
			      instr_suf);
		s->cur_prompt->instr_reqd = TRUE;
		add_prompt(s->cur_prompt, prompt, FALSE, SSH_MAX_PASSWORD_LEN);
		sfree(instr_suf);
	    }
	}
	if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
	    s->cur_prompt->to_server = TRUE;
	    s->cur_prompt->name = dupstr("SSH password");
	    add_prompt(s->cur_prompt, dupprintf("%.90s@%.90s's password: ",
						s->username, ssh->savedhost),









		       FALSE, SSH_MAX_PASSWORD_LEN);
















	}

	/*
	 * Show password prompt, having first obtained it via a TIS
	 * or CryptoCard exchange if we're doing TIS or CryptoCard
	 * authentication.
	 */
	{
	    int ret; /* need not be kept over crReturn */
	    ret = get_userpass_input(s->cur_prompt, NULL, 0);
	    while (ret < 0) {
		ssh->send_ok = 1;
		crWaitUntil(!pktin);
		ret = get_userpass_input(s->cur_prompt, in, inlen);
		ssh->send_ok = 0;
	    }
	    if (!ret) {
		/*
		 * Failed to get a password (for example
		 * because one was supplied on the command line
		 * which has already failed to work). Terminate.
		 */
		free_prompts(s->cur_prompt);
		ssh_disconnect(ssh, NULL, "Unable to authenticate", 0, TRUE);



























































		crStop(0);
	    }
	}









































	if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
	    /*
	     * Defence against traffic analysis: we send a
	     * whole bunch of packets containing strings of
	     * different lengths. One of these strings is the
	     * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
	     * The others are all random data in
	     * SSH1_MSG_IGNORE packets. This way a passive
	     * listener can't tell which is the password, and
	     * hence can't deduce the password length.
	     * 
	     * Anybody with a password length greater than 16
	     * bytes is going to have enough entropy in their
	     * password that a listener won't find it _that_
	     * much help to know how long it is. So what we'll
	     * do is:
	     * 
	     *  - if password length < 16, we send 15 packets
	     *    containing string lengths 1 through 15
	     * 
	     *  - otherwise, we let N be the nearest multiple
	     *    of 8 below the password length, and send 8
	     *    packets containing string lengths N through
	     *    N+7. This won't obscure the order of
	     *    magnitude of the password length, but it will
	     *    introduce a bit of extra uncertainty.
	     * 
	     * A few servers (the old 1.2.18 through 1.2.22)
	     * can't deal with SSH1_MSG_IGNORE. For these
	     * servers, we need an alternative defence. We make
	     * use of the fact that the password is interpreted
	     * as a C string: so we can append a NUL, then some
	     * random data.
	     * 
	     * One server (a Cisco one) can deal with neither
	     * SSH1_MSG_IGNORE _nor_ a padded password string.
	     * For this server we are left with no defences
	     * against password length sniffing.
	     */
	    if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
		/*
		 * The server can deal with SSH1_MSG_IGNORE, so
		 * we can use the primary defence.
		 */
		int bottom, top, pwlen, i;
		char *randomstr;

		pwlen = strlen(s->cur_prompt->prompts[0]->result);
		if (pwlen < 16) {
		    bottom = 0;    /* zero length passwords are OK! :-) */
		    top = 15;
		} else {
		    bottom = pwlen & ~7;
		    top = bottom + 7;
		}

		assert(pwlen >= bottom && pwlen <= top);

		randomstr = snewn(top + 1, char);

		for (i = bottom; i <= top; i++) {
		    if (i == pwlen) {
			defer_packet(ssh, s->pwpkt_type,
				     PKTT_PASSWORD, PKT_STR,
				     s->cur_prompt->prompts[0]->result,
				     PKTT_OTHER, PKT_END);
		    } else {
			for (j = 0; j < i; j++) {
			    do {
				randomstr[j] = random_byte();
			    } while (randomstr[j] == '\0');
			}
			randomstr[i] = '\0';
			defer_packet(ssh, SSH1_MSG_IGNORE,
				     PKT_STR, randomstr, PKT_END);
		    }
		}
		logevent("Sending password with camouflage packets");
		ssh_pkt_defersend(ssh);
		sfree(randomstr);
	    } 
	    else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
		/*
		 * The server can't deal with SSH1_MSG_IGNORE
		 * but can deal with padded passwords, so we
		 * can use the secondary defence.
		 */
		char string[64];
		char *ss;
		int len;

		len = strlen(s->cur_prompt->prompts[0]->result);
		if (len < sizeof(string)) {
		    ss = string;
		    strcpy(string, s->cur_prompt->prompts[0]->result);
		    len++;	       /* cover the zero byte */
		    while (len < sizeof(string)) {
			string[len++] = (char) random_byte();
		    }
		} else {
		    ss = s->cur_prompt->prompts[0]->result;
		}
		logevent("Sending length-padded password");
		send_packet(ssh, s->pwpkt_type, PKTT_PASSWORD,
			    PKT_INT, len, PKT_DATA, ss, len,
			    PKTT_OTHER, PKT_END);
	    } else {
		/*
		 * The server has _both_
		 * BUG_CHOKES_ON_SSH1_IGNORE and
		 * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
		 * therefore nothing we can do.
		 */
		int len;
		len = strlen(s->cur_prompt->prompts[0]->result);
		logevent("Sending unpadded password");
		send_packet(ssh, s->pwpkt_type,
			    PKTT_PASSWORD, PKT_INT, len,
			    PKT_DATA, s->cur_prompt->prompts[0]->result, len,
			    PKTT_OTHER, PKT_END);
	    }
	} else {
	    send_packet(ssh, s->pwpkt_type, PKTT_PASSWORD,
			PKT_STR, s->cur_prompt->prompts[0]->result,
			PKTT_OTHER, PKT_END);
	}

	logevent("Sent password");
	free_prompts(s->cur_prompt);
	crWaitUntil(pktin);
	if (pktin->type == SSH1_SMSG_FAILURE) {
	    if (flags & FLAG_VERBOSE)
		c_write_str(ssh, "Access denied\r\n");
	    logevent("Authentication refused");
	} else if (pktin->type != SSH1_SMSG_SUCCESS) {
	    bombout(("Strange packet received, type %d", pktin->type));
	    crStop(0);
	}
    }

    /* Clear up */
    if (s->publickey_blob) {
	sfree(s->publickey_blob);
	sfree(s->publickey_comment);
    }

    logevent("Authentication successful");

    crFinish(1);
}

void sshfwd_close(struct ssh_channel *c)

		AUTH_TYPE_PASSWORD,
		AUTH_TYPE_KEYBOARD_INTERACTIVE,
		AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
	} type;
	int done_service_req;
	int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
	int tried_pubkey_config, tried_agent;
	int kbd_inter_refused;
	int we_are_in;
	prompts_t *cur_prompt;
	int num_prompts;
	char username[100];
	int got_username;


	void *publickey_blob;
	int publickey_bloblen;
	int publickey_encrypted;
	char *publickey_algorithm;
	char *publickey_comment;
	unsigned char request[5], *response, *p;
	int responselen;
	int keyi, nkeys;
	int authed;
	char *pkblob, *alg, *commentp;
	int pklen, alglen, commentlen;
	int siglen, retlen, len;

	if (pktin->type == SSH2_MSG_SERVICE_ACCEPT) {
	    s->we_are_in = TRUE; /* no auth required */
	} else {
	    bombout(("Server refused service request"));
	    crStopV;
	}
    }

    /*
     * Misc one-time setup for authentication.
     */
    s->publickey_blob = NULL;
    if (!s->we_are_in) {

	/*
	 * Load the public half of any configured public key file
	 * for later use.
	 */
	if (!filename_is_null(ssh->cfg.keyfile)) {
	    int keytype;
	    logeventf(ssh, "Reading private key file \"%.150s\"",
		      filename_to_str(&ssh->cfg.keyfile));
	    keytype = key_type(&ssh->cfg.keyfile);
	    if (keytype == SSH_KEYTYPE_SSH2) {
		const char *error;
		s->publickey_blob =
		    ssh2_userkey_loadpub(&ssh->cfg.keyfile,
					 &s->publickey_algorithm,
					 &s->publickey_bloblen, 
					 &s->publickey_comment, &error);
		if (s->publickey_blob) {
		    s->publickey_encrypted =
			ssh2_userkey_encrypted(&ssh->cfg.keyfile, NULL);
		} else {
		    char *msgbuf;
		    logeventf(ssh, "Unable to load private key (%s)", 
			      error);
		    msgbuf = dupprintf("Unable to load private key file "
				       "\"%.150s\" (%s)\r\n",
				       filename_to_str(&ssh->cfg.keyfile),
				       error);
		    c_write_str(ssh, msgbuf);
		    sfree(msgbuf);
		}
	    } else {
		char *msgbuf;
		logeventf(ssh, "Unable to use this key file (%s)",
			  key_type_to_str(keytype));
		msgbuf = dupprintf("Unable to use key file \"%.150s\""
				   " (%s)\r\n",
				   filename_to_str(&ssh->cfg.keyfile),
				   key_type_to_str(keytype));
		c_write_str(ssh, msgbuf);
		sfree(msgbuf);
		s->publickey_blob = NULL;
	    }
	}

    }

    /*
     * We repeat this whole loop, including the username prompt,
     * until we manage a successful authentication. If the user
     * types the wrong _password_, they can be sent back to the
     * beginning to try another username, if this is configured on.
     * (If they specify a username in the config, they are never

	if (s->got_username && !ssh->cfg.change_username) {
	    /*
	     * We got a username last time round this loop, and
	     * with change_username turned off we don't try to get
	     * it again.
	     */
	} else if (!*ssh->cfg.username) {
	    int ret; /* need not be kept over crReturn */
	    s->cur_prompt = new_prompts(ssh->frontend);
	    s->cur_prompt->to_server = TRUE;
	    s->cur_prompt->name = dupstr("SSH login name");
	    add_prompt(s->cur_prompt, dupstr("login as: "), TRUE,
		       lenof(s->username)); 
	    ret = get_userpass_input(s->cur_prompt, NULL, 0);
	    while (ret < 0) {
		ssh->send_ok = 1;
		crWaitUntilV(!pktin);
		ret = get_userpass_input(s->cur_prompt, in, inlen);
		ssh->send_ok = 0;
	    }
	    if (!ret) {
		/*
		 * get_userpass_input() failed to get a username.
		 * Terminate.
		 */
		free_prompts(s->cur_prompt);
		ssh_disconnect(ssh, "No username provided", NULL, 0, TRUE);
		crStopV;
	    }




	    memcpy(s->username, s->cur_prompt->prompts[0]->result,








		   lenof(s->username));
	    free_prompts(s->cur_prompt);
	} else {
	    char *stuff;
	    strncpy(s->username, ssh->cfg.username, sizeof(s->username));
	    s->username[sizeof(s->username)-1] = '\0';
	    if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
		stuff = dupprintf("Using username \"%s\".\r\n", s->username);
		c_write_str(ssh, stuff);

	ssh2_pkt_send(ssh, s->pktout);
	s->type = AUTH_TYPE_NONE;
	s->gotit = FALSE;
	s->we_are_in = FALSE;

	s->tried_pubkey_config = FALSE;
	s->tried_agent = FALSE;

	s->kbd_inter_refused = FALSE;

























	while (1) {
	    /*
	     * Wait for the result of the last authentication request.
	     */
	    if (!s->gotit)
		crWaitUntilV(pktin);

	    }
	    if (pktin->type == SSH2_MSG_USERAUTH_SUCCESS) {
		logevent("Access granted");
		s->we_are_in = TRUE;
		break;
	    }












	    if (pktin->type == SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ) {
		/* FIXME: perhaps we should support this? */
		bombout(("PASSWD_CHANGEREQ not yet supported"));
		crStopV;
	    } else if (pktin->type != SSH2_MSG_USERAUTH_FAILURE) {
		bombout(("Strange packet received during authentication: type %d",
			 pktin->type));
		crStopV;
	    }

	    s->gotit = FALSE;

	    /*
	     * OK, we're now sitting on a USERAUTH_FAILURE message, so
	     * we can look at the string in it and know what we can
	     * helpfully try next.
	     */
	    if (pktin->type == SSH2_MSG_USERAUTH_FAILURE) {
		char *methods;
		int methlen;
		ssh_pkt_getstring(pktin, &methods, &methlen);

		if (!ssh2_pkt_getbool(pktin)) {
		    /*
		     * We have received an unequivocal Access
		     * Denied. This can translate to a variety of
		     * messages:
		     * 
		     *  - if we'd just tried "none" authentication,

		    in_commasep_string("publickey", methods, methlen);
		s->can_passwd =
		    in_commasep_string("password", methods, methlen);
		s->can_keyb_inter = ssh->cfg.try_ki_auth &&
		    in_commasep_string("keyboard-interactive", methods, methlen);
	    }


	    ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;









	    if (s->can_pubkey && agent_exists() && !s->tried_agent) {



		/*
		 * Attempt public-key authentication using Pageant.
		 */
		void *r;
		s->authed = FALSE;

		ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;

			    }
			}
		    }
		    if (s->authed)
			continue;
		}
		sfree(s->response);


	    } else if (s->can_pubkey && s->publickey_blob &&
		       !s->tried_pubkey_config) {





		struct ssh2_userkey *key;   /* not live over crReturn */
		char *passphrase;	    /* not live over crReturn */

		ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
		ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;

		s->tried_pubkey_config = TRUE;

		/*
		 * Try the public key supplied in the configuration.
		 *
		 * First, offer the public blob to see if the server is
		 * willing to accept it.
		 */






		s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
		ssh2_pkt_addstring(s->pktout, s->username);
		ssh2_pkt_addstring(s->pktout, "ssh-connection");
						/* service requested */
		ssh2_pkt_addstring(s->pktout, "publickey");	/* method */
		ssh2_pkt_addbool(s->pktout, FALSE);
						/* no signature included */
		ssh2_pkt_addstring(s->pktout, s->publickey_algorithm);
		ssh2_pkt_addstring_start(s->pktout);
		ssh2_pkt_addstring_data(s->pktout,
					(char *)s->publickey_blob,
					s->publickey_bloblen);
		ssh2_pkt_send(ssh, s->pktout);
		logevent("Offered public key");

		crWaitUntilV(pktin);
		if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
		    /* Key refused. Give up. */
		    s->gotit = TRUE; /* reconsider message next loop */
		    s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
		    continue; /* process this new message */
		}
		s->method = AUTH_PUBLICKEY_FILE;
		logevent("Offer of public key accepted");

		/*
		 * Actually attempt a serious authentication using
		 * the key.
		 */








		if (flags & FLAG_VERBOSE) {
		    c_write_str(ssh, "Authenticating with public key \"");
		    c_write_str(ssh, s->publickey_comment);
		    c_write_str(ssh, "\"\r\n");
		}



		key = NULL;




		while (!key) {


		    const char *error;  /* not live over crReturn */





		    if (s->publickey_encrypted) {

			/*




			 * Get a passphrase from the user.

			 */
			int ret; /* need not be kept over crReturn */


			s->cur_prompt = new_prompts(ssh->frontend);


			s->cur_prompt->to_server = FALSE;

			s->cur_prompt->name = dupstr("SSH key passphrase");
			add_prompt(s->cur_prompt,


				   dupprintf("Passphrase for key \"%.100s\": ",
					     s->publickey_comment),
				   FALSE, SSH_MAX_PASSWORD_LEN);
			ret = get_userpass_input(s->cur_prompt, NULL, 0);
			while (ret < 0) {







			    ssh->send_ok = 1;
			    crWaitUntilV(!pktin);


			    ret = get_userpass_input(s->cur_prompt,
						     in, inlen);

			    ssh->send_ok = 0;
			}
			if (!ret) {





			    /* Failed to get a passphrase. Terminate. */






			    free_prompts(s->cur_prompt);
			    ssh_disconnect(ssh, NULL,


					   "Unable to authenticate",

					   SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
					   TRUE);






			    crStopV;
			}
			passphrase =
			    dupstr(s->cur_prompt->prompts[0]->result);
			free_prompts(s->cur_prompt);



		    } else {


			passphrase = NULL; /* no passphrase needed */







		    }





		    /*




		     * Try decrypting the key.
		     */


		    key = ssh2_load_userkey(&ssh->cfg.keyfile, passphrase,
					    &error);

		    if (passphrase) {
			/* burn the evidence */
			memset(passphrase, 0, strlen(passphrase));
			sfree(passphrase);
		    }


























		    if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
			if (passphrase &&
			    (key == SSH2_WRONG_PASSPHRASE)) {
			    c_write_str(ssh, "Wrong passphrase\r\n");
			    key = NULL;
			    /* and loop again */
			} else {
			    c_write_str(ssh, "Unable to load private key (");
			    c_write_str(ssh, error);
			    c_write_str(ssh, ")\r\n");
			    key = NULL;
			    break; /* try something else */
			}
		    }
		}







		if (key) {
		    unsigned char *pkblob, *sigblob, *sigdata;
		    int pkblob_len, sigblob_len, sigdata_len;
		    int p;

		    /*
		     * We have loaded the private key and the server
		     * has announced that it's willing to accept it.
		     * Hallelujah. Generate a signature and send it.
		     */
		    s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
		    ssh2_pkt_addstring(s->pktout, s->username);
		    ssh2_pkt_addstring(s->pktout, "ssh-connection");
						    /* service requested */
		    ssh2_pkt_addstring(s->pktout, "publickey");
						    /* method */
		    ssh2_pkt_addbool(s->pktout, TRUE);
						    /* signature follows */
		    ssh2_pkt_addstring(s->pktout, key->alg->name);
		    pkblob = key->alg->public_blob(key->data,
						   &pkblob_len);
		    ssh2_pkt_addstring_start(s->pktout);
		    ssh2_pkt_addstring_data(s->pktout, (char *)pkblob,
					    pkblob_len);

		    /*
		     * The data to be signed is:
		     *
		     *   string  session-id
		     *
		     * followed by everything so far placed in the
		     * outgoing packet.
		     */
		    sigdata_len = s->pktout->length - 5 + 4 +
			ssh->v2_session_id_len;
		    if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
			sigdata_len -= 4;
		    sigdata = snewn(sigdata_len, unsigned char);
		    p = 0;
		    if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) {
			PUT_32BIT(sigdata+p, ssh->v2_session_id_len);
			p += 4;
		    }
		    memcpy(sigdata+p, ssh->v2_session_id,
			   ssh->v2_session_id_len);
		    p += ssh->v2_session_id_len;
		    memcpy(sigdata+p, s->pktout->data + 5,
			   s->pktout->length - 5);
		    p += s->pktout->length - 5;
		    assert(p == sigdata_len);
		    sigblob = key->alg->sign(key->data, (char *)sigdata,
					     sigdata_len, &sigblob_len);
		    ssh2_add_sigblob(ssh, s->pktout, pkblob, pkblob_len,
				     sigblob, sigblob_len);
		    sfree(pkblob);
		    sfree(sigblob);
		    sfree(sigdata);

		    ssh2_pkt_send(ssh, s->pktout);
		    s->type = AUTH_TYPE_PUBLICKEY;
		    key->alg->freekey(key->data);
		}

	    } else if (s->can_keyb_inter && !s->kbd_inter_refused) {

		/*
		 * Keyboard-interactive authentication.
		 */
		char *name, *inst, *lang;
		int name_len, inst_len, lang_len;
		int i;

		s->method = AUTH_KEYBOARD_INTERACTIVE;
		s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;

		ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
		ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;

		s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
		ssh2_pkt_addstring(s->pktout, s->username);
		ssh2_pkt_addstring(s->pktout, "ssh-connection");
							/* service requested */
		ssh2_pkt_addstring(s->pktout, "keyboard-interactive");
							/* method */
		ssh2_pkt_addstring(s->pktout, "");	/* lang */
		ssh2_pkt_addstring(s->pktout, "");	/* submethods */
		ssh2_pkt_send(ssh, s->pktout);

		crWaitUntilV(pktin);
		if (pktin->type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
		    /* Server is not willing to do keyboard-interactive
		     * at all. Give up on it entirely. */
		    s->gotit = TRUE;
		    if (pktin->type == SSH2_MSG_USERAUTH_FAILURE)
			logevent("Keyboard-interactive authentication refused");
		    s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
		    s->kbd_inter_refused = TRUE; /* don't try it again */
		    continue;
		}

		/*
		 * We've got a fresh USERAUTH_INFO_REQUEST.
		 * Get the preamble and start building a prompt.
		 */
		ssh_pkt_getstring(pktin, &name, &name_len);
		ssh_pkt_getstring(pktin, &inst, &inst_len);
		ssh_pkt_getstring(pktin, &lang, &lang_len);
		s->cur_prompt = new_prompts(ssh->frontend);
		s->cur_prompt->to_server = TRUE;
		if (name_len) {
		    /* FIXME: better prefix to distinguish from
		     * local prompts? */
		    s->cur_prompt->name = dupprintf("SSH server: %.*s",
						    name_len, name);
		    s->cur_prompt->name_reqd = TRUE;
		} else {
		    s->cur_prompt->name = dupstr("SSH server authentication");
		    s->cur_prompt->name_reqd = FALSE;
		}
		s->cur_prompt->instruction =
		    dupprintf("Using keyboard-interactive authentication.%s%.*s",
			      inst_len ? "\n" : "", inst_len, inst);
		s->cur_prompt->instr_reqd = TRUE;

		/*
		 * Get the prompts from the packet.
		 */
		s->num_prompts = ssh_pkt_getuint32(pktin);
		for (i = 0; i < s->num_prompts; i++) {
		    char *prompt;
		    int prompt_len;
		    int echo;
		    static char noprompt[] =
			"<server failed to send prompt>: ";

		    ssh_pkt_getstring(pktin, &prompt, &prompt_len);
		    echo = ssh2_pkt_getbool(pktin);
		    if (!prompt_len) {
			prompt = noprompt;
			prompt_len = lenof(noprompt)-1;
		    }
		    add_prompt(s->cur_prompt,
			       dupprintf("%.*s", prompt_len, prompt),
			       echo, SSH_MAX_PASSWORD_LEN);
		}

		/*
		 * Get the user's responses.
		 */
		if (s->num_prompts) {
		    int ret; /* not live over crReturn */
		    ret = get_userpass_input(s->cur_prompt, NULL, 0);
		    while (ret < 0) {
			ssh->send_ok = 1;
			crWaitUntilV(!pktin);
			ret = get_userpass_input(s->cur_prompt, in, inlen);
			ssh->send_ok = 0;
		    }
		    if (!ret) {
			/*
			 * Failed to get responses. Terminate.
			 */
			free_prompts(s->cur_prompt);
			ssh_disconnect(ssh, NULL, "Unable to authenticate",
				       SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
				       TRUE);
			crStopV;
		    }
		}

		/*
		 * Send the responses to the server.
		 */
		s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE);
		s->pktout->forcepad = 256;
		ssh2_pkt_adduint32(s->pktout, s->num_prompts);
		for (i=0; i < s->num_prompts; i++) {
		    dont_log_password(ssh, s->pktout, PKTLOG_BLANK);
		    ssh2_pkt_addstring(s->pktout,
				       s->cur_prompt->prompts[i]->result);
		    end_log_omission(ssh, s->pktout);
		}
		ssh2_pkt_send(ssh, s->pktout);
		s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE; /*FIXME?*/

	    } else if (s->can_passwd) {

		/*
		 * Plain old password authentication.
		 */
		int ret; /* not live over crReturn */

		s->method = AUTH_PASSWORD;
		ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
		ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD;

		s->cur_prompt = new_prompts(ssh->frontend);
		s->cur_prompt->to_server = TRUE;
		s->cur_prompt->name = dupstr("SSH password");
		add_prompt(s->cur_prompt, dupprintf("%.90s@%.90s's password: ",
						    s->username,
						    ssh->savedhost),
			   FALSE, SSH_MAX_PASSWORD_LEN);

		ret = get_userpass_input(s->cur_prompt, NULL, 0);
		while (ret < 0) {
		    ssh->send_ok = 1;
		    crWaitUntilV(!pktin);
		    ret = get_userpass_input(s->cur_prompt, in, inlen);
		    ssh->send_ok = 0;
		}
		if (!ret) {
		    /*
		     * Failed to get responses. Terminate.
		     */
		    free_prompts(s->cur_prompt);
		    ssh_disconnect(ssh, NULL, "Unable to authenticate",
				   SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER,
				   TRUE);
		    crStopV;
		}

		/*
		 * Send the password packet.
		 *
		 * We pad out the password packet to 256 bytes to make
		 * it harder for an attacker to find the length of the
		 * user's password.
		 *
		 * Anyone using a password longer than 256 bytes
		 * probably doesn't have much to worry about from
		 * people who find out how long their password is!
		 */
		s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
		s->pktout->forcepad = 256;
		ssh2_pkt_addstring(s->pktout, s->username);
		ssh2_pkt_addstring(s->pktout, "ssh-connection");
							/* service requested */
		ssh2_pkt_addstring(s->pktout, "password");
		ssh2_pkt_addbool(s->pktout, FALSE);
		dont_log_password(ssh, s->pktout, PKTLOG_BLANK);
		ssh2_pkt_addstring(s->pktout,
				   s->cur_prompt->prompts[0]->result);
		free_prompts(s->cur_prompt);
		end_log_omission(ssh, s->pktout);
		ssh2_pkt_send(ssh, s->pktout);
		logevent("Sent password");
		s->type = AUTH_TYPE_PASSWORD; /*FIXME?*/















	    } else {












		ssh_disconnect(ssh, NULL,
			       "No supported authentication methods available",
			       SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE,
			       FALSE);
		crStopV;

	    }

	}
    }
    ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = NULL;

    /* Clear up various bits and pieces from authentication. */
    if (s->publickey_blob) {
	sfree(s->publickey_blob);
	sfree(s->publickey_comment);
    }

    /*
     * Now the connection protocol has started, one way or another.
     */

    ssh->channels = newtree234(ssh_channelcmp);