搜尋此網誌

2007/08/24

網路穿牆術:使用VPN來突破網路限制(三) - stunnel篇

STunnel的作用是將在個人的電腦要送到外部SOCKS伺服器的資料,經過加密的步驟送出,在送給SOCKS伺服器前才解密。


如第一篇的圖所示,SOCKS伺服器本身並不直接接收個人電腦的資料,而是接收stunnel解密後的資料。Stunnel分二部份,一部份是伺服器端,在此次的實作中,STunnel伺服器和SOCKS伺服器是裝在同一台,這表示SOCKS伺服器只接受Stunnel伺服器的要求,故SOCKS只允許127.0.0.1來的資料即可。
而在個人電腦端的STunnel,則扮演著Client端的角色。負責將資料送出去前加密。加密的動作是透過SSL而且在此實作中,我們在Stunnel的伺服器和用戶端,皆產生一個新的私鑰,以確保資料的保密性。
STunnel最重要的就是私鑰,下載時附的私鑰是一點安全性也沒有的,故我們要用OpenSSL先產生私鑰。以下的例子為產生10年期的私鑰:


d:\openssl\>openssl req -new -x509 -days 3650 -nodes -config ./openssl.cnf -out s
em -keyout stunnel.pem
Loading 'screen' into random state - done
Generating a 1024 bit RSA private key
.........++++++
....................++++++
unable to write 'random state'
writing new private key to 'stunnel.pem'
-----
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [CA]:TW
State or Province Name (full name) [Quebec]:Taipei
Locality Name (eg, city) [Montreal]:Taipei
Organization Name (eg, company) [Open Network Architecture]:Private Use
Organizational Unit Name (eg, section) [Internet Department]:N/A
Common Name (eg, YOUR name) [www.openna.com]:localhost
Email Address [admin@openna.com]:root@localhost


OpenSSL要一個設定檔openssl.cnf才能運作,Windows版的OpenSSL並沒有這個檔案,以下是該設定檔的例子:


# OpenSSL example configuration file.
# This is mostly being used for generation of certificate requests.
#

RANDFILE = D:\openssl\rnd
oid_file = D:\openssl\oid
oid_section = new_oids

# To use this configuration file with the "-extfile" option of the
# "openssl x509" utility, name here the section containing the
# X.509v3 extensions to use:
# extensions =
# (Alternatively, use a configuration file that has only
# X.509v3 extensions in its main [= default] section.)

[ new_oids ]

# We can add new OIDs in here for use by 'ca' and 'req'.
# Add a simple OID like this:
# testoid1=1.2.3.4
# Or use config file substitution like this:
# testoid2=${testoid1}.5.6

####################################################################
[ ca ]
default_ca = CA_default # The default ca section

####################################################################
[ CA_default ]

dir = D:\openssl\ # Where everything is kept
certs = $dir/certs # Where the issued certs are kept
crl_dir = $dir/crl # Where the issued crl are kept
database = $dir/ca.db.index # database index file.
new_certs_dir = $dir/ca.db.certs # default place for new certs.

certificate = $dir/certs/ca.crt # The CA certificate
serial = $dir/ca.db.serial # The current serial number
crl = $dir/crl.pem # The current CRL
private_key = $dir/private/ca.key # The private key
RANDFILE = $dir/ca.db.rand # private random number file

x509_extensions = usr_cert # The extentions to add to the cert

# Extensions to add to a CRL. Note: Netscape communicator chokes on V2 CRLs
# so this is commented out by default to leave a V1 CRL.
# crl_extensions = crl_ext

default_days = 365 # how long to certify for
default_crl_days = 30 # how long before next CRL
default_md = md5 # which md to use.
Preserve = no # keep passed DN ordering

# A few difference way of specifying how similar the request should look
# For type CA, the listed attributes must be the same, and the optional
# and supplied fields are just that :-)
policy = policy_match

# For the CA policy
[ policy_match ]
countryName = match
stateOrProvinceName = match
organizationName = match
organizationalUnitName = optional
commonName = supplied
emailAddress = optional

# For the 'anything' policy
# At this point in time, you must list all acceptable 'object'
# types.
[ policy_anything ]
countryName = optional
stateOrProvinceName = optional
localityName = optional
organizationName = optional
organizationalUnitName = optional
commonName = supplied
emailAddress = optional

####################################################################
[ req ]
default_bits = 1024
default_keyfile = privkey.pem
distinguished_name = req_distinguished_name
attributes = req_attributes
x509_extensions = v3_ca # The extentions to add to the self signed cert

[ req_distinguished_name ]
countryName = Country Name (2 letter code)
countryName_default = CA
countryName_min = 2
countryName_max = 2

stateOrProvinceName = State or Province Name (full name)
stateOrProvinceName_default = Quebec

localityName = Locality Name (eg, city)
localityName_default = Montreal

0.organizationName = Organization Name (eg, company)
0.organizationName_default = Open Network Architecture

# we can do this but it is not needed normally :-)
#1.organizationName = Second Organization Name (eg, company)
#1.organizationName_default = World Wide Web Pty Ltd

organizationalUnitName = Organizational Unit Name (eg, section)
organizationalUnitName_default = Internet Department

commonName = Common Name (eg, YOUR name)
commonName_default = www.openna.com
commonName_max = 64

emailAddress = Email Address
emailAddress_default = admin@openna.com
emailAddress_max = 40

# SET-ex3 = SET extension number 3

[ req_attributes ]
challengePassword = A challenge password
challengePassword_min = 4
challengePassword_max = 20

unstructuredName = An optional company name

[ usr_cert ]

# These extensions are added when 'ca' signs a request.

# This goes against PKIX guidelines but some CAs do it and some software
# requires this to avoid interpreting an end user certificate as a CA.

basicConstraints=CA:FALSE

# Here are some examples of the usage of nsCertType. If it is omitted
# the certificate can be used for anything *except* object signing.

# This is OK for an SSL server.
# nsCertType = server

# For an object signing certificate this would be used.
# nsCertType = objsign

# For normal client use this is typical
# nsCertType = client, email

# and for everything including object signing:
# nsCertType = client, email, objsign

# This is typical in keyUsage for a client certificate.
# keyUsage = nonRepudiation, digitalSignature, keyEncipherment

# This will be displayed in Netscape's comment listbox.
nsComment = "OpenSSL Generated Certificate"

# PKIX recommendations harmless if included in all certificates.
subjectKeyIdentifier=hash
authorityKeyIdentifier=keyid,issuer:always

# This stuff is for subjectAltName and issuerAltname.
# Import the email address.
# subjectAltName=email:copy

# Copy subject details
# issuerAltName=issuer:copy

#nsCaRevocationUrl = http://www.domain.dom/ca-crl.pem
#nsBaseUrl
#nsRevocationUrl
#nsRenewalUrl
#nsCaPolicyUrl
#nsSslServerName

[ v3_ca]

# Extensions for a typical CA


# PKIX recommendation.

subjectKeyIdentifier=hash

authorityKeyIdentifier=keyid:always,issuer:always

# This is what PKIX recommends but some broken software chokes on critical
# extensions.
#basicConstraints = critical,CA:true
# So we do this instead.
basicConstraints = CA:true

# Key usage: this is typical for a CA certificate. However since it will
# prevent it being used as an test self-signed certificate it is best
# left out by default.
# keyUsage = cRLSign, keyCertSign

# Some might want this also
# nsCertType = sslCA, emailCA

# Include email address in subject alt name: another PKIX recommendation
# subjectAltName=email:copy
# Copy issuer details
# issuerAltName=issuer:copy

# RAW DER hex encoding of an extension: beware experts only!
# 1.2.3.5=RAW:02:03
# You can even override a supported extension:
# basicConstraints= critical, RAW:30:03:01:01:FF

[ crl_ext ]
# CRL extensions.
# Only issuerAltName and authorityKeyIdentifier make any sense in a CRL.

# issuerAltName=issuer:copy
authorityKeyIdentifier=keyid:always,issuer:always


產生好二個私鑰,分別放在伺服器和用戶端的STunnel目錄的中。
再來就是STunnel伺服器端的設定STunnel.conf:


; cert後面接著放私鑰的檔名
cert = stunnel.pem
socket = l:TCP_NODELAY=1
socket = r:TCP_NODELAY=1
; rle壓縮,不用zip是因為zip較吃CPU
compression = rle
; 除錯開到最大
debug = 7
output = stunnel.log
[socks2ssl]
;接受8080 Port
accept = 8080
;連到1080 Port出去
connect = 127.0.0.1:1080



STunnel用戶端的設定STunnel.conf:


cert = stunnel.pem
socket = l:TCP_NODELAY=1
socket = r:TCP_NODELAY=1

compression = rle
debug = 7
output = stunnel.log

; 用戶端模式,此例子為有經過公司的Proxy出去的狀況,並且在公司的Web Proxy並不用密碼的情況下所設計,如果Web Proxy要密碼(例如要NT的帳號認證),那就要在PC端,再架一台二級代理,例如NTLMAPS代理伺服器。
client = yes
[socks2ssl]
;接受SocksCap從1081 Port
accept = localhost:1081

;Proxy Server的IP和Port
connect = 192.168.0.250:80

;遠端電腦的IP和STunnelPort
protocolHost = 10.1.1.250:8080
protocol = connect
delay = yes

;下方為3proxy中設定的帳號密碼
protocolPassword = abc123
protocolUsername = user1

; 下方為簡易模式
;[socks2ssl]
;accept = localhost:1081
;connect = 172.20.254.225:8080



設定好後,執行二端的STunnel,這部份就算完成。

網路穿牆術:使用VPN來突破網路限制(二) 3proxy 篇

首先先介紹在外部主機的「對外連線伺服器」,這軟體主要是負責接收解密後的資料,真正連線到網際網路的部份。


這裡我們要架的,其實就是一台SOCKS伺服器,基於安全,我選用了SOCKS5的通訊協定。SOKS5可以設定帳號和密碼,故不是任何人都能連線。
3proxy是一套免費可的,可在Windows平台上執行的SOCKS伺服器,其實它有多種代理伺服器的功能,SOCKS只是其中之一。
3proxy設定:
解開3proxy的ZIP檔後,在cfg的目錄有一個叫3proxy.cfg.sample的檔案,為了方便起見,複製一份到bin的目錄,並改名為3proxy.cfg,並修改之,或是用以下的設定來修改:


#!/usr/local/bin/3proxy
nscache 65536
timeouts 1 5 30 60 180 1800 15 60
# users設定帳號名和密碼,上方設定帳號user1,密碼為123abc明碼
users user1:CL:123abc
service

#設定記錄檔路徑
log C:\3proxy\logs\3proxy.log D
logformat "- +_L%t.%. %N.%p %E %U %C:%c %R:%r %O %I %h %T"
archiver rar rar a -df -inul %A %F
rotate 30
auth iponly
# external 設定外部IP,0.0.0.0表示全部,不建議使用
external 0.0.0.0

# 內部IP
internal 127.0.0.1

auth strong
flush
# 下方的allow設定只認可某些IP才能連上來
allow 192.168.0.1,127.0.0.1
# 下方的allow設定只認可某些帳號可使用
allow user1
#
# 最大連線數
maxconn 20
socks


改好後存檔,接著執行3proxy.exe就行了。

2007/08/15

網路穿牆術:使用VPN來突破網路限制(一)

不管是校園網路,還是企業網路,都一定有防火牆,如果有些網站真的要連,但是又被阻擋,或是要收取重要的信件,但是該網頁進不去時,就必需自行打開一個通道,來達成這個目的。

在此只說明如何實作,對於做出這樣的環境後,所造成的任何後果,本人不負任何責任


通常,在校園網路或是企業的網路,基於安全的考量,一定會加裝防火牆,以防止不明的入侵。現今網路的發達,宅男之多,有如過江之鯽,尤其是線上遊戲的發達,更是讓無數的人每天坐在位置上殺得你死我活。
所以,通常有設防火牆的網路環境,都不能連線上遊戲,或是收取外部信件。一般來說,有保全的網路環境如下:

通常這類有網路保全的環境,只許可網頁瀏覽(TCP Port 80/443/8080),要連線其它的TCP Port是不行的。

但是,我們可以經由可連線的TCP Port,連到一台位在外部的主機,以該主機當跳板,來達到完全沒有限制的網路連線,中間還可把資料加密後,讓中間任何的想看封包的軟體,看不到內容,達到隱藏傳輸內容的目的。示意圖如下:


要做到這樣的環境,我們要有:
  • 加密/解密
  • 有一個能讓程式連出去的中介軟體
  • 一台在外部的主機
  • 在解密完後,能從外部主機出去的伺服器軟體


故實際上我們需要的軟體和架構如下:

計有:
  • STunnel
  • 3proxy
  • sockscap

2007/08/09

每年一度的健檢

公司每年一度都會有健康檢查,當然啦,不外就是抽血,驗尿,量體重。年年一樣,只期望紅字別愈來愈多就好。


感覺上,今年的員工健檢來得特別早,以前好像都是在九月以後。健檢,沒什麼特別的,不外就是抽血,驗尿,量體重,照X光,再來個視力檢查。不過雖然沒花多少時間,沒檢查的話相關單位可是要你補做的。
今天的結果會比較爛吧!檢查前幾天東西照吃,不管清不清淡,也沒早睡。其實我覺得這才是正常的身體狀況。雖然醫護人員還是說作息要正常,不過那樣感覺就是有一點假。
今年的抽血倒是有點特別,根據經驗,來抽血的護士都是較有經驗的,我就隨便找了一個排,沒想到就因為這樣踢到鐵板。
一坐上去,我就很習慣的伸出右手,告訴護士要打哪裡(因為我打過不少次orz),不過護士說看不到(難道是肥油護體!?)接著他看了一下左手臂,選定了一個地方:

深呼吸

俺乖乖的吸了一口氣,接著我看那個針頭好像沒長眼似的,在我的手上攪啊攪的,就是沒打到血管。

這時我的身上已經滿身汗了

接著這位護士就投降了,她的以乞求的眼神看著隔壁那位看似更老資格的護士。我只好乖乖的換位置。這位資深護士呢,在右手看了看,找了一個和左手臂相對的位置,打了進去,攪個二下後,就看到血液進針筒了。

我總算放心了....

不過他也問了一句話:「你怎麼一直流冷汗?你看來血糖不夠哦,快去吃一點東西,不然等一下暈倒!

這位大姊,我是看到那針在那攪來攪去,有若游魚,心中緊張啦~.~
後來二隻手上各一個紅點,右手還有點淤青,心中忽然間閃過了「毒蟲」二個字。還好我只被打了二針。

我已經把你的故事告訴其他人了」A君笑著說
看吧,告訴你別找漂亮的,要找夠經驗的,要其他人引以為戒

真是夠了orz