void
chan_obuf_empty(Channel *c)
{
    debug2("channel %d: obuf empty", c->self);
    if (buffer_len(&c->output)) {
        error("channel %d: chan_obuf_empty for non empty buffer",
              c->self);
        return;
    }
    switch (c->ostate) {
    case CHAN_OUTPUT_WAIT_DRAIN:
        chan_shutdown_write(c);
        if (!compat20)
            chan_send_oclose1(c);
        chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
        break;
    default:
        error("channel %d: internal error: obuf_empty for ostate %d",
              c->self, c->ostate);
        break;
    }
}

static void
input_gssapi_mic(int type, u_int32_t plen, void *ctxt)
{
	Authctxt *authctxt = ctxt;
	Gssctxt *gssctxt;
	int authenticated = 0;
	Buffer b;
	gss_buffer_desc mic, gssbuf;
	u_int len;

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

	gssctxt = authctxt->methoddata;

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

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

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

	if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
		authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
	else
		logit("GSSAPI MIC check failed");

	buffer_free(&b);
	free(mic.value);

	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);
}

/* Confirmation hash calculation */
void
jpake_confirm_hash(const BIGNUM *k,
    const u_char *endpoint_id, u_int endpoint_id_len,
    const u_char *sess_id, u_int sess_id_len,
    u_char **confirm_hash, u_int *confirm_hash_len)
{
	Buffer b;

	/*
	 * Calculate confirmation proof:
	 *     client: H(k || client_id || session_id)
	 *     server: H(k || server_id || session_id)
	 */
	buffer_init(&b);
	buffer_put_bignum2(&b, k);
	buffer_put_string(&b, endpoint_id, endpoint_id_len);
	buffer_put_string(&b, sess_id, sess_id_len);
	if (hash_buffer(buffer_ptr(&b), buffer_len(&b), EVP_sha256(),
	    confirm_hash, confirm_hash_len) != 0)
		fatal("%s: hash_buffer", __func__);
	buffer_free(&b);
}

/*
 * Retrieves a BIGNUM from the buffer.
 */
int
buffer_get_bignum_ret(Buffer *buffer, BIGNUM *value)
{
	u_int bits, bytes;
	u_char buf[2], *bin;

	/* Get the number of bits. */
	if (buffer_get_ret(buffer, (char *) buf, 2) == -1) {
		error("buffer_get_bignum_ret: invalid length");
		return (-1);
	}
	bits = get_u16(buf);
	if (bits > 65535-7) {
		error("buffer_get_bignum_ret: cannot handle BN of size %d",
		    bits);
		return (-1);
	}
	/* Compute the number of binary bytes that follow. */
	bytes = (bits + 7) / 8;
	if (bytes > 8 * 1024) {
		error("buffer_get_bignum_ret: cannot handle BN of size %d", bytes);
		return (-1);
	}
	if (buffer_len(buffer) < bytes) {
		error("buffer_get_bignum_ret: input buffer too small");
		return (-1);
	}
	bin = buffer_ptr(buffer);
	if (BN_bin2bn(bin, bytes, value) == NULL) {
		error("buffer_get_bignum_ret: BN_bin2bn failed");
		return (-1);
	}
	if (buffer_consume_ret(buffer, bytes) == -1) {
		error("buffer_get_bignum_ret: buffer_consume failed");
		return (-1);
	}
	return (0);
}

static void
roaming_auth_required(void)
{
	u_char digest[SHA_DIGEST_LENGTH];
	EVP_MD_CTX md;
	Buffer b;
	const EVP_MD *evp_md = EVP_sha1();
	u_int64_t chall, oldchall;

	chall = packet_get_int64();
	oldchall = packet_get_int64();
	if (oldchall != lastseenchall) {
		key1 = oldkey1;
		key2 = oldkey2;
	}
	lastseenchall = chall;

	buffer_init(&b);
	buffer_put_int64(&b, cookie);
	buffer_put_int64(&b, chall);
	EVP_DigestInit(&md, evp_md);
	EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
	EVP_DigestFinal(&md, digest, NULL);
	buffer_free(&b);

	packet_start(SSH2_MSG_KEX_ROAMING_AUTH);
	packet_put_int64(key1 ^ get_recv_bytes());
	packet_put_raw(digest, sizeof(digest));
	packet_send();

	oldkey1 = key1;
	oldkey2 = key2;
	calculate_new_key(&key1, cookie, chall);
	calculate_new_key(&key2, cookie, chall);

	debug("Received %llu bytes", (unsigned long long)get_recv_bytes());
	debug("Sent roaming_auth packet");
}

/*
 * Init HTTP compression
 */
int http_compression_buffer_init(struct session *s, struct buffer *in, struct buffer *out)
{
	struct http_msg *msg = &s->txn.rsp;
	int left;

	/* not enough space */
	if (in->size - buffer_len(in) < 40)
	    return -1;

	/*
	 * Skip data, we don't need them in the new buffer. They are results
	 * of CHUNK_CRLF and CHUNK_SIZE parsing.
	 */
	b_adv(in, msg->next);
	msg->next = 0;
	msg->sov = 0;
	msg->sol = 0;

	out->size = global.tune.bufsize;
	out->i = 0;
	out->o = 0;
	out->p = out->data;
	/* copy output data */
	if (in->o > 0) {
		left = in->o - bo_contig_data(in);
		memcpy(out->data, bo_ptr(in), bo_contig_data(in));
		out->p += bo_contig_data(in);
		if (left > 0) { /* second part of the buffer */
			memcpy(out->p, in->data, left);
			out->p += left;
		}
		out->o = in->o;
	}
	out->i += http_emit_chunk_size(out->p, 0, 0);

	return 0;
}

void buffer_uncompress(Buffer * input_buffer, Buffer * output_buffer)
{
    char buf[4096];
    int status;

    incoming_stream.next_in = (unsigned char *) buffer_ptr(input_buffer);
    incoming_stream.avail_in = buffer_len(input_buffer);

    incoming_stream.next_out = (unsigned char *) buf;
    incoming_stream.avail_out = sizeof(buf);

    for (;;) {
        status = inflate(&incoming_stream, Z_PARTIAL_FLUSH);
        switch (status) {
        case Z_OK:
            buffer_append(output_buffer, buf, sizeof(buf) - incoming_stream.avail_out);
            incoming_stream.next_out = (unsigned char *) buf;
            incoming_stream.avail_out = sizeof(buf);
            break;
        case Z_STREAM_END:
            fatal("buffer_uncompress: inflate returned Z_STREAM_END");
         /*NOTREACHED*/ case Z_DATA_ERROR:
            fatal("buffer_uncompress: inflate returned Z_DATA_ERROR");
         /*NOTREACHED*/ case Z_STREAM_ERROR:
            fatal("buffer_uncompress: inflate returned Z_STREAM_ERROR");
         /*NOTREACHED*/ case Z_BUF_ERROR:
            /* Comments in zlib.h say that we should keep calling inflate()
               until we get an error.  This appears to be the error that we
               get. */
            return;
        case Z_MEM_ERROR:
            fatal("buffer_uncompress: inflate returned Z_MEM_ERROR");
         /*NOTREACHED*/ default:
            fatal("buffer_uncompress: inflate returned %d", status);
        }
    }
}

void
input_userauth_banner(int type, u_int32_t seq, void *ctxt)
{
	char *msg, *lang;

	debug3("input_userauth_banner");
	msg = packet_get_utf8_string(NULL);
	lang = packet_get_string(NULL);
	/*
	 * Banner is a warning message according to RFC 4252. So, never print
	 * a banner in error log level or lower. If the log level is higher,
	 * use DisableBanner option to decide whether to display it or not.
	 */
	if (options.log_level > SYSLOG_LEVEL_ERROR) {
		if (options.disable_banner == 0 ||
		    (options.disable_banner == SSH_NO_BANNER_IN_EXEC_MODE &&
		    buffer_len(&command) == 0)) {
			msg = g11n_filter_string(msg);
			(void) fprintf(stderr, "%s", msg);
		}
	}
	xfree(msg);
	xfree(lang);
}

/*
 * Filters a proposal string, excluding any algorithm matching the 'filter'
 * pattern list.
 */
static char *
filter_proposal(char *proposal, const char *filter)
{
	Buffer b;
	char *orig_prop, *fix_prop;
	char *cp, *tmp;

	buffer_init(&b);
	tmp = orig_prop = xstrdup(proposal);
	while ((cp = strsep(&tmp, ",")) != NULL) {
		if (match_pattern_list(cp, filter, 0) != 1) {
			if (buffer_len(&b) > 0)
				buffer_append(&b, ",", 1);
			buffer_append(&b, cp, strlen(cp));
		} else
			debug2("Compat: skipping algorithm \"%s\"", cp);
	}
	buffer_append(&b, "\0", 1);
	fix_prop = xstrdup((char *)buffer_ptr(&b));
	buffer_free(&b);
	free(orig_prop);

	return fix_prop;
}

/*
 * Wait until all buffered output has been sent to the client.
 * This is used when the program terminates.
 */
static void
drain_output(void)
{
	/* Send any buffered stdout data to the client. */
	if (buffer_len(&stdout_buffer) > 0) {
		packet_start(SSH_SMSG_STDOUT_DATA);
		packet_put_string(buffer_ptr(&stdout_buffer),
				  buffer_len(&stdout_buffer));
		packet_send();
		/* Update the count of sent bytes. */
		stdout_bytes += buffer_len(&stdout_buffer);
	}
	/* Send any buffered stderr data to the client. */
	if (buffer_len(&stderr_buffer) > 0) {
		packet_start(SSH_SMSG_STDERR_DATA);
		packet_put_string(buffer_ptr(&stderr_buffer),
				  buffer_len(&stderr_buffer));
		packet_send();
		/* Update the count of sent bytes. */
		stderr_bytes += buffer_len(&stderr_buffer);
	}
	/* Wait until all buffered data has been written to the client. */
	packet_write_wait();
}

void
userauth_finish(Authctxt *authctxt, int authenticated, const char *method,
    const char *submethod)
{
	char *methods;
	int partial = 0;

	if (!authctxt->valid && authenticated)
		fatal("INTERNAL ERROR: authenticated invalid user %s",
		    authctxt->user);
	if (authenticated && authctxt->postponed)
		fatal("INTERNAL ERROR: authenticated and postponed");

	/* Special handling for root */
	if (authenticated && authctxt->pw->pw_uid == 0 &&
	    !auth_root_allowed(method)) {
		authenticated = 0;
#ifdef SSH_AUDIT_EVENTS
		PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
#endif
	}

	if (authenticated && options.num_auth_methods != 0) {
		if (!auth2_update_methods_lists(authctxt, method, submethod)) {
			authenticated = 0;
			partial = 1;
		}
	}

	/* Log before sending the reply */
	auth_log(authctxt, authenticated, partial, method, submethod);

	if (authctxt->postponed)
		return;

#ifdef USE_PAM
	if (options.use_pam && authenticated) {
		if (!PRIVSEP(do_pam_account())) {
			/* if PAM returned a message, send it to the user */
			if (buffer_len(&loginmsg) > 0) {
				buffer_append(&loginmsg, "\0", 1);
				userauth_send_banner(buffer_ptr(&loginmsg));
				packet_write_wait();
			}
			fatal("Access denied for user %s by PAM account "
			    "configuration", authctxt->user);
		}
	}
#endif

#ifdef _UNICOS
	if (authenticated && cray_access_denied(authctxt->user)) {
		authenticated = 0;
		fatal("Access denied for user %s.", authctxt->user);
	}
#endif /* _UNICOS */

	if (authenticated == 1) {
		/* turn off userauth */
		dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
		packet_start(SSH2_MSG_USERAUTH_SUCCESS);
		packet_send();
		packet_write_wait();
		/* now we can break out */
		authctxt->success = 1;
	} else {

		/* Allow initial try of "none" auth without failure penalty */
		if (!authctxt->server_caused_failure &&
		    (authctxt->attempt > 1 || strcmp(method, "none") != 0))
			authctxt->failures++;
		if (authctxt->failures >= options.max_authtries) {
#ifdef SSH_AUDIT_EVENTS
			PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
#endif
			packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
		}
		methods = authmethods_get(authctxt);
		debug3("%s: failure partial=%d next methods=\"%s\"", __func__,
		    partial, methods);
		packet_start(SSH2_MSG_USERAUTH_FAILURE);
		packet_put_cstring(methods);
		packet_put_char(partial);
		packet_send();
		packet_write_wait();
		free(methods);
	}
}

BOOL generate_SSH2_keysign(Key *keypair, char **sigptr, int *siglen, char *data, int datalen)
{
	buffer_t *msg = NULL;
	char *s;
	int ret;

	msg = buffer_init();
	if (msg == NULL) {
		// TODO: error check
		return FALSE;
	}

	switch (keypair->type) {
	case KEY_RSA: // RSA
	{
		const EVP_MD *evp_md = EVP_sha1();
		EVP_MD_CTX md;
		u_char digest[EVP_MAX_MD_SIZE], *sig;
		u_int slen, dlen, len;
		int ok, nid = NID_sha1;

		// ダイジェスト値の計算
		EVP_DigestInit(&md, evp_md);
		EVP_DigestUpdate(&md, data, datalen);
		EVP_DigestFinal(&md, digest, &dlen);

		slen = RSA_size(keypair->rsa);
		sig = malloc(slen);
		if (sig == NULL)
			goto error;

		// 電子署名を計算
		ok = RSA_sign(nid, digest, dlen, sig, &len, keypair->rsa);
		memset(digest, 'd', sizeof(digest));
		if (ok != 1) { // error
			free(sig);
			goto error;
		}
		// 署名のサイズがバッファより小さい場合、後ろへずらす。先頭はゼロで埋める。
		if (len < slen) {
			u_int diff = slen - len;
			memmove(sig + diff, sig, len);
			memset(sig, 0, diff);

		} else if (len > slen) {
			free(sig);
			goto error;

		} else {
			// do nothing

		}

		s = get_sshname_from_key(keypair);
		buffer_put_string(msg, s, strlen(s));
		buffer_append_length(msg, sig, slen);
		len = buffer_len(msg);

		// setting
		*siglen = len;
		*sigptr = malloc(len);
		if (*sigptr == NULL) {
			free(sig);
			goto error;
		}
		memcpy(*sigptr, buffer_ptr(msg), len);
		free(sig);
		
		break;
	}
	case KEY_DSA: // DSA
	{
		DSA_SIG *sig;
		const EVP_MD *evp_md = EVP_sha1();
		EVP_MD_CTX md;
		u_char digest[EVP_MAX_MD_SIZE], sigblob[SIGBLOB_LEN];
		u_int rlen, slen, len, dlen;

		// ダイジェストの計算
		EVP_DigestInit(&md, evp_md);
		EVP_DigestUpdate(&md, data, datalen);
		EVP_DigestFinal(&md, digest, &dlen);

		// DSA電子署名を計算
		sig = DSA_do_sign(digest, dlen, keypair->dsa);
		memset(digest, 'd', sizeof(digest));
		if (sig == NULL) {
			goto error;
		}

		// BIGNUMからバイナリ値への変換
		rlen = BN_num_bytes(sig->r);
		slen = BN_num_bytes(sig->s);
		if (rlen > INTBLOB_LEN || slen > INTBLOB_LEN) {
			DSA_SIG_free(sig);
			goto error;
		}
		memset(sigblob, 0, SIGBLOB_LEN);
		BN_bn2bin(sig->r, sigblob+ SIGBLOB_LEN - INTBLOB_LEN - rlen);
		BN_bn2bin(sig->s, sigblob+ SIGBLOB_LEN - slen);
//.........这里部分代码省略.........

/* RSASSA-PKCS1-v1_5 (PKCS #1 v2.0 signature) with SHA1 */
int
ssh_rsa_sign(const Key *key, u_char **sigp, u_int *lenp,
    const u_char *data, u_int datalen)
{
	const EVP_MD *evp_md;
	EVP_MD_CTX md;
	u_char digest[EVP_MAX_MD_SIZE], *sig;
	u_int slen, dlen, len;
	int ok, nid;
	Buffer b;

	if (key == NULL ||
	    (key->type != KEY_RSA && key->type != KEY_RSA_CERT) ||
	    key->rsa == NULL) {
		error("ssh_rsa_sign: no RSA key");
		return -1;
	}
	nid = (datafellows & SSH_BUG_RSASIGMD5) ? NID_md5 : NID_sha1;
	if ((evp_md = EVP_get_digestbynid(nid)) == NULL) {
		error("ssh_rsa_sign: EVP_get_digestbynid %d failed", nid);
		return -1;
	}
	EVP_DigestInit(&md, evp_md);
	EVP_DigestUpdate(&md, data, datalen);
	EVP_DigestFinal(&md, digest, &dlen);

	slen = RSA_size(key->rsa);
	sig = xmalloc(slen);

	ok = RSA_sign(nid, digest, dlen, sig, &len, key->rsa);
	memset(digest, 'd', sizeof(digest));

	if (ok != 1) {
		int ecode = ERR_get_error();

		error("ssh_rsa_sign: RSA_sign failed: %s",
		    ERR_error_string(ecode, NULL));
		xfree(sig);
		return -1;
	}
	if (len < slen) {
		u_int diff = slen - len;
		debug("slen %u > len %u", slen, len);
		memmove(sig + diff, sig, len);
		memset(sig, 0, diff);
	} else if (len > slen) {
		error("ssh_rsa_sign: slen %u slen2 %u", slen, len);
		xfree(sig);
		return -1;
	}
	/* encode signature */
	buffer_init(&b);
	buffer_put_cstring(&b, "ssh-rsa");
	buffer_put_string(&b, sig, slen);
	len = buffer_len(&b);
	if (lenp != NULL)
		*lenp = len;
	if (sigp != NULL) {
		*sigp = xmalloc(len);
		memcpy(*sigp, buffer_ptr(&b), len);
	}
	buffer_free(&b);
	memset(sig, 's', slen);
	xfree(sig);

	return 0;
}

int
ssh_rsa_verify(const Key *key, const u_char *signature, u_int signaturelen,
    const u_char *data, u_int datalen)
{
	Buffer b;
	const EVP_MD *evp_md;
	EVP_MD_CTX md;
	char *ktype;
	u_char digest[EVP_MAX_MD_SIZE], *sigblob;
	u_int len, dlen, modlen;
	int rlen, ret, nid;

	if (key == NULL ||
	    (key->type != KEY_RSA && key->type != KEY_RSA_CERT) ||
	    key->rsa == NULL) {
		error("ssh_rsa_verify: no RSA key");
		return -1;
	}
	if (BN_num_bits(key->rsa->n) < SSH_RSA_MINIMUM_MODULUS_SIZE) {
		error("ssh_rsa_verify: RSA modulus too small: %d < minimum %d bits",
		    BN_num_bits(key->rsa->n), SSH_RSA_MINIMUM_MODULUS_SIZE);
		return -1;
	}
	buffer_init(&b);
	buffer_append(&b, signature, signaturelen);
	ktype = buffer_get_string(&b, NULL);
	if (strcmp("ssh-rsa", ktype) != 0) {
		error("ssh_rsa_verify: cannot handle type %s", ktype);
		buffer_free(&b);
		xfree(ktype);
		return -1;
	}
	xfree(ktype);
	sigblob = buffer_get_string(&b, &len);
	rlen = buffer_len(&b);
	buffer_free(&b);
	if (rlen != 0) {
		error("ssh_rsa_verify: remaining bytes in signature %d", rlen);
		xfree(sigblob);
		return -1;
	}
	/* RSA_verify expects a signature of RSA_size */
	modlen = RSA_size(key->rsa);
	if (len > modlen) {
		error("ssh_rsa_verify: len %u > modlen %u", len, modlen);
		xfree(sigblob);
		return -1;
	} else if (len < modlen) {
		u_int diff = modlen - len;
		debug("ssh_rsa_verify: add padding: modlen %u > len %u",
		    modlen, len);
		sigblob = xrealloc(sigblob, 1, modlen);
		memmove(sigblob + diff, sigblob, len);
		memset(sigblob, 0, diff);
		len = modlen;
	}
	nid = (datafellows & SSH_BUG_RSASIGMD5) ? NID_md5 : NID_sha1;
	if ((evp_md = EVP_get_digestbynid(nid)) == NULL) {
		error("ssh_rsa_verify: EVP_get_digestbynid %d failed", nid);
		xfree(sigblob);
		return -1;
	}
	EVP_DigestInit(&md, evp_md);
	EVP_DigestUpdate(&md, data, datalen);
	EVP_DigestFinal(&md, digest, &dlen);

	ret = openssh_RSA_verify(nid, digest, dlen, sigblob, len, key->rsa);
	memset(digest, 'd', sizeof(digest));
	memset(sigblob, 's', len);
	xfree(sigblob);
	debug("ssh_rsa_verify: signature %scorrect", (ret==0) ? "in" : "");
	return ret;
}

//.........这里部分代码省略.........
	OpenSSL_add_all_algorithms();
	ERR_load_crypto_strings();

	/* Initialize the command to execute on remote host. */
	buffer_init(&command);

	if (options.request_tty == REQUEST_TTY_YES ||
	    options.request_tty == REQUEST_TTY_FORCE)
		tty_flag = 1;

	/*
	 * Save the command to execute on the remote host in a buffer. There
	 * is no limit on the length of the command, except by the maximum
	 * packet size.  Also sets the tty flag if there is no command.
	 */
	if (!ac) {
		/* No command specified - execute shell on a tty. */
		tty_flag = options.request_tty != REQUEST_TTY_NO;
		if (subsystem_flag) {
			fprintf(stderr,
			    "You must specify a subsystem to invoke.\n");
			usage();
		}
	} else {
		/* A command has been specified.  Store it into the buffer. */
		for (i = 0; i < ac; i++) {
			if (i)
				buffer_append(&command, " ", 1);
			buffer_append(&command, av[i], strlen(av[i]));
		}
	}

	/* Cannot fork to background if no command. */
	if (fork_after_authentication_flag && buffer_len(&command) == 0 &&
	    !no_shell_flag)
		fatal("Cannot fork into background without a command "
		    "to execute.");

	/* Allocate a tty by default if no command specified. */
	if (buffer_len(&command) == 0)
		tty_flag = options.request_tty != REQUEST_TTY_NO;

	/* Force no tty */
	if (options.request_tty == REQUEST_TTY_NO || muxclient_command != 0)
		tty_flag = 0;
	/* Do not allocate a tty if stdin is not a tty. */
	if ((!isatty(fileno(stdin)) || stdin_null_flag) &&
	    options.request_tty != REQUEST_TTY_FORCE) {
		if (tty_flag)
			logit("Pseudo-terminal will not be allocated because "
			    "stdin is not a terminal.");
		tty_flag = 0;
	}

	/*
	 * Initialize "log" output.  Since we are the client all output
	 * actually goes to stderr.
	 */
	log_init(argv0,
	    options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
	    SYSLOG_FACILITY_USER, !use_syslog);

	/*
	 * Read per-user configuration file.  Ignore the system wide config
	 * file if the user specifies a config file on the command line.
	 */

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, slen, sbloblen, hashlen;
	int kout;

	/* generate and send 'e', client DH public key */
	switch (kex->kex_type) {
	case KEX_DH_GRP1_SHA1:
		dh = dh_new_group1();
		break;
	case KEX_DH_GRP14_SHA1:
		dh = dh_new_group14();
		break;
	default:
		fatal("%s: Unexpected KEX type %d", __func__, kex->kex_type);
	}
	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 (server_host_key->type != kex->hostkey_type)
		fatal("type mismatch for decoded 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 parameter 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);
	if ((kout = DH_compute_key(kbuf, dh_server_pub, dh)) < 0)
		fatal("DH_compute_key: failed");
#ifdef DEBUG_KEXDH
	dump_digest("shared secret", kbuf, kout);
#endif
	if ((shared_secret = BN_new()) == NULL)
		fatal("kexdh_client: BN_new failed");
	if (BN_bin2bn(kbuf, kout, shared_secret) == NULL)
		fatal("kexdh_client: BN_bin2bn failed");
	memset(kbuf, 0, klen);
	free(kbuf);

	/* calc and verify H */
	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,
	    &hash, &hashlen
	);
	free(server_host_key_blob);
	BN_clear_free(dh_server_pub);
	DH_free(dh);

	if (key_verify(server_host_key, signature, slen, hash, hashlen) != 1)
//.........这里部分代码省略.........

void
mm_send_keystate(struct monitor *monitor)
{
	Buffer m, *input, *output;
	u_char *blob, *p;
	u_int bloblen, plen;
	u_int32_t seqnr, packets;
	u_int64_t blocks, bytes;

	buffer_init(&m);

	if (!compat20) {
		u_char iv[24];
		u_char *key;
		u_int ivlen, keylen;

		buffer_put_int(&m, packet_get_protocol_flags());

		buffer_put_int(&m, packet_get_ssh1_cipher());

		debug3("%s: Sending ssh1 KEY+IV", __func__);
		keylen = packet_get_encryption_key(NULL);
		key = xmalloc(keylen+1);	/* add 1 if keylen == 0 */
		keylen = packet_get_encryption_key(key);
		buffer_put_string(&m, key, keylen);
		memset(key, 0, keylen);
		xfree(key);

		ivlen = packet_get_keyiv_len(MODE_OUT);
		packet_get_keyiv(MODE_OUT, iv, ivlen);
		buffer_put_string(&m, iv, ivlen);
		ivlen = packet_get_keyiv_len(MODE_OUT);
		packet_get_keyiv(MODE_IN, iv, ivlen);
		buffer_put_string(&m, iv, ivlen);
		goto skip;
	} else {
		/* Kex for rekeying */
		mm_send_kex(&m, *monitor->m_pkex);
	}

	debug3("%s: Sending new keys: %p %p",
	    __func__, packet_get_newkeys(MODE_OUT),
	    packet_get_newkeys(MODE_IN));

	/* Keys from Kex */
	if (!mm_newkeys_to_blob(MODE_OUT, &blob, &bloblen))
		fatal("%s: conversion of newkeys failed", __func__);

	buffer_put_string(&m, blob, bloblen);
	xfree(blob);

	if (!mm_newkeys_to_blob(MODE_IN, &blob, &bloblen))
		fatal("%s: conversion of newkeys failed", __func__);

	buffer_put_string(&m, blob, bloblen);
	xfree(blob);

	packet_get_state(MODE_OUT, &seqnr, &blocks, &packets, &bytes);
	buffer_put_int(&m, seqnr);
	buffer_put_int64(&m, blocks);
	buffer_put_int(&m, packets);
	buffer_put_int64(&m, bytes);
	packet_get_state(MODE_IN, &seqnr, &blocks, &packets, &bytes);
	buffer_put_int(&m, seqnr);
	buffer_put_int64(&m, blocks);
	buffer_put_int(&m, packets);
	buffer_put_int64(&m, bytes);

	debug3("%s: New keys have been sent", __func__);
 skip:
	/* More key context */
	plen = packet_get_keycontext(MODE_OUT, NULL);
	p = xmalloc(plen+1);
	packet_get_keycontext(MODE_OUT, p);
	buffer_put_string(&m, p, plen);
	xfree(p);

	plen = packet_get_keycontext(MODE_IN, NULL);
	p = xmalloc(plen+1);
	packet_get_keycontext(MODE_IN, p);
	buffer_put_string(&m, p, plen);
	xfree(p);

	/* Compression state */
	debug3("%s: Sending compression state", __func__);
	buffer_put_string(&m, &outgoing_stream, sizeof(outgoing_stream));
	buffer_put_string(&m, &incoming_stream, sizeof(incoming_stream));

	/* Network I/O buffers */
	input = (Buffer *)packet_get_input();
	output = (Buffer *)packet_get_output();
	buffer_put_string(&m, buffer_ptr(input), buffer_len(input));
	buffer_put_string(&m, buffer_ptr(output), buffer_len(output));

	/* Roaming */
	if (compat20) {
		buffer_put_int64(&m, get_sent_bytes());
		buffer_put_int64(&m, get_recv_bytes());
	}

//.........这里部分代码省略.........

static int
userauth_pubkey(Authctxt *authctxt)
{
	Buffer b;
	Key *key = NULL;
	char *pkalg;
	u_char *pkblob, *sig;
	u_int alen, blen, slen;
	int have_sig, pktype;
	int authenticated = 0;

	if (!authctxt->valid) {
		debug2("userauth_pubkey: disabled because of invalid user");
		return 0;
	}
	have_sig = packet_get_char();
	if (datafellows & SSH_BUG_PKAUTH) {
		debug2("userauth_pubkey: SSH_BUG_PKAUTH");
		/* no explicit pkalg given */
		pkblob = packet_get_string(&blen);
		buffer_init(&b);
		buffer_append(&b, pkblob, blen);
		/* so we have to extract the pkalg from the pkblob */
		pkalg = buffer_get_string(&b, &alen);
		buffer_free(&b);
	} else {
		pkalg = packet_get_string(&alen);
		pkblob = packet_get_string(&blen);
	}
	pktype = key_type_from_name(pkalg);
	if (pktype == KEY_UNSPEC) {
		/* this is perfectly legal */
		logit("userauth_pubkey: unsupported public key algorithm: %s",
		    pkalg);
		goto done;
	}
	key = key_from_blob(pkblob, blen);
	if (key == NULL) {
		error("userauth_pubkey: cannot decode key: %s", pkalg);
		goto done;
	}
	if (key->type != pktype) {
		error("userauth_pubkey: type mismatch for decoded key "
		    "(received %d, expected %d)", key->type, pktype);
		goto done;
	}
	if (have_sig) {
		sig = packet_get_string(&slen);
		packet_check_eom();
		buffer_init(&b);
		if (datafellows & SSH_OLD_SESSIONID) {
			buffer_append(&b, session_id2, session_id2_len);
		} else {
			buffer_put_string(&b, session_id2, session_id2_len);
		}
		/* reconstruct packet */
		buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
		buffer_put_cstring(&b, authctxt->user);
		buffer_put_cstring(&b,
		    datafellows & SSH_BUG_PKSERVICE ?
		    "ssh-userauth" :
		    authctxt->service);
		if (datafellows & SSH_BUG_PKAUTH) {
			buffer_put_char(&b, have_sig);
		} else {
			buffer_put_cstring(&b, "publickey");
			buffer_put_char(&b, have_sig);
			buffer_put_cstring(&b, pkalg);
		}
		buffer_put_string(&b, pkblob, blen);
#ifdef DEBUG_PK
		buffer_dump(&b);
#endif
		/* test for correct signature */
		authenticated = 0;
		if (PRIVSEP(user_key_allowed(authctxt->pw, key)) &&
		    PRIVSEP(key_verify(key, sig, slen, buffer_ptr(&b),
		    buffer_len(&b))) == 1)
			authenticated = 1;
		buffer_free(&b);
		xfree(sig);
	} else {
		debug("test whether pkalg/pkblob are acceptable");
		packet_check_eom();

		/* XXX fake reply and always send PK_OK ? */
		/*
		 * XXX this allows testing whether a user is allowed
		 * to login: if you happen to have a valid pubkey this
		 * message is sent. the message is NEVER sent at all
		 * if a user is not allowed to login. is this an
		 * issue? -markus
		 */
		if (PRIVSEP(user_key_allowed(authctxt->pw, key))) {
			packet_start(SSH2_MSG_USERAUTH_PK_OK);
			packet_put_string(pkalg, alen);
			packet_put_string(pkblob, blen);
			packet_send();
			packet_write_wait();
			authctxt->postponed = 1;
//.........这里部分代码省略.........

//.........这里部分代码省略.........

		/*
		 * If we started challenge-response authentication but the
		 * next packet is not a response to our challenge, release
		 * the resources allocated by get_challenge() (which would
		 * normally have been released by verify_response() had we
		 * received such a response)
		 */
		if (prev == SSH_CMSG_AUTH_TIS &&
		    type != SSH_CMSG_AUTH_TIS_RESPONSE)
			abandon_challenge_response(authctxt);

		if (authctxt->failures >= options.max_authtries)
			goto skip;
		if ((meth = lookup_authmethod1(type)) == NULL) {
			logit("Unknown message during authentication: "
			    "type %d", type);
			goto skip;
		}

		if (!*(meth->enabled)) {
			verbose("%s authentication disabled.", meth->name);
			goto skip;
		}

		authenticated = meth->method(authctxt);
		if (authenticated == -1)
			continue; /* "postponed" */

#ifdef BSD_AUTH
		if (authctxt->as) {
			auth_close(authctxt->as);
			authctxt->as = NULL;
		}
#endif
		if (!authctxt->valid && authenticated)
			fatal("INTERNAL ERROR: authenticated invalid user %s",
			    authctxt->user);

#ifdef _UNICOS
		if (authenticated && cray_access_denied(authctxt->user)) {
			authenticated = 0;
			fatal("Access denied for user %s.",authctxt->user);
		}
#endif /* _UNICOS */

#ifndef HAVE_CYGWIN
		/* Special handling for root */
		if (authenticated && authctxt->pw->pw_uid == 0 &&
		    !auth_root_allowed(meth->name)) {
 			authenticated = 0;
# ifdef SSH_AUDIT_EVENTS
			PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
# endif
		}
#endif

#ifdef USE_PAM
		if (options.use_pam && authenticated &&
		    !PRIVSEP(do_pam_account())) {
			char *msg;
			size_t len;

			error("Access denied for user %s by PAM account "
			    "configuration", authctxt->user);
			len = buffer_len(&loginmsg);
			buffer_append(&loginmsg, "\0", 1);
			msg = buffer_ptr(&loginmsg);
			/* strip trailing newlines */
			if (len > 0)
				while (len > 0 && msg[--len] == '\n')
					msg[len] = '\0';
			else
				msg = "Access denied.";
			packet_disconnect("%s", msg);
		}
#endif

 skip:
		/* Log before sending the reply */
		auth_log(authctxt, authenticated, 0, get_authname(type), NULL);

		free(client_user);
		client_user = NULL;

		if (authenticated)
			return;

		if (++authctxt->failures >= options.max_authtries) {
#ifdef SSH_AUDIT_EVENTS
			PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
#endif
			packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
		}

		packet_start(SSH_SMSG_FAILURE);
		packet_send();
		packet_write_wait();
	}
}

int
main(int ac, char **av)
{
	fd_set *rset, *wset;
	int in, out, max;
	ssize_t len, olen, set_size;

	/* XXX should use getopt */

	__progname = get_progname(av[0]);
	handle_init();

#ifdef DEBUG_SFTP_SERVER
	log_init("sftp-server", SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 0);
#endif

	in = dup(STDIN_FILENO);
	out = dup(STDOUT_FILENO);

#ifdef HAVE_CYGWIN
	setmode(in, O_BINARY);
	setmode(out, O_BINARY);
#endif

	max = 0;
	if (in > max)
		max = in;
	if (out > max)
		max = out;

	buffer_init(&iqueue);
	buffer_init(&oqueue);

	set_size = howmany(max + 1, NFDBITS) * sizeof(fd_mask);
	rset = (fd_set *)xmalloc(set_size);
	wset = (fd_set *)xmalloc(set_size);

	for (;;) {
		memset(rset, 0, set_size);
		memset(wset, 0, set_size);

		FD_SET(in, rset);
		olen = buffer_len(&oqueue);
		if (olen > 0)
			FD_SET(out, wset);

		if (select(max+1, rset, wset, NULL, NULL) < 0) {
			if (errno == EINTR)
				continue;
			exit(2);
		}

		/* copy stdin to iqueue */
		if (FD_ISSET(in, rset)) {
			char buf[4*4096];
			len = read(in, buf, sizeof buf);
			if (len == 0) {
				debug("read eof");
				exit(0);
			} else if (len < 0) {
				error("read error");
				exit(1);
			} else {
				buffer_append(&iqueue, buf, len);
			}
		}
		/* send oqueue to stdout */
		if (FD_ISSET(out, wset)) {
			len = write(out, buffer_ptr(&oqueue), olen);
			if (len < 0) {
				error("write error");
				exit(1);
			} else {
				buffer_consume(&oqueue, len);
			}
		}
		/* process requests from client */
		process();
	}
}