背景
做基于radius的双因子认证，但未找到一个方便测试的radius服务器，网上找了freeradius，折腾了很久没有搞定，想了想是否可以自己写一个，只要有一个radius的雏形，发一个challenge应该是比较简单的。
pyrad
找到了pyrad，这个是提供一个radius的基本操作的库，提供了客户端和服务端的库，试了一下服务端，windows上起不来，于是只能从头写。
基本思路是自己创建一个udp socket，进行监听，收到报文后，使用pyrad进行解析，然后做身份验证的处理，再用pyrad创建回应消息。
代码如下：
from pyrad import *
import socket
import pyrad.host
import random
BUFSIZE = 1024
KEY = b"testing123"
CHALLENGE = "test2"
class RadiusServer(pyrad.host.Host):
def __init__(self):
dict = pyrad.dictionary.Dictionary("dictionary.rfc2865") #从freeradius中搞一个通用的字典使用
pyrad.host.Host.__init__(self, dict=dict)
def get_challenge(self): #产生一个4字节的随机挑战码
challenge = ""
challenge = challenge + str(chr(random.randint(65,90)))
challenge = challenge + str(chr(random.randint(65,90)))
challenge = challenge + str(chr(random.randint(65,90)))
challenge = challenge + str(chr(random.randint(65,90)))
return challenge
def check_pass(self, radpkt): #检查用户名密码，这里简单处理一下，如果密码是test则发起挑战，如果输入正确的挑战码，回应正确，否则失败
global CHALLENGE
print("check user")
if radpkt.PwCrypt(CHALLENGE) == radpkt["User-Password"][0]:
radpkt.code = packet.AccessAccept
CHALLENGE = self.get_challenge() #挑战码使用过后就更换掉
print("AccessAccept")
elif radpkt.PwCrypt("test") == radpkt["User-Password"][0]:
radpkt.code = packet.AccessChallenge
CHALLENGE = self.get_challenge()
radpkt.AddAttribute("Reply-Message", CHALLENGE) #把挑战码发给客户端
print("AccessChallenge， please input", CHALLENGE)
else:
radpkt.code = packet.AccessReject
print("AccessReject")
def get_pkt(self, pkt):
get_pw = None
get_name = None
radpkt = self.CreateAuthPacket(packet=pkt) #解析请求报文
print("code:", radpkt.code)
print("authenticator:", radpkt.authenticator)
print("id:", radpkt.id)
#radpkt.code = packet.AccessChallenge
radpkt.secret = KEY
for key in radpkt.keys():
print(key, radpkt[key])
if key == "User-Password":
get_pw = 1
if key == "User-Name":
get_name = 1
if 1 == get_pw and 1 == get_name:
self.check_pass(radpkt)
return radpkt.ReplyPacket()
ip_port = ('', 1812)
server = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) # udp协议
server.bind(ip_port)
while True:
data,client_addr = server.recvfrom(BUFSIZE)
srv = RadiusServer()
reply = srv.get_pkt(data)
server.sendto(reply, client_addr)
测试，采用freeradius中自带的ratest进行测试。
使用第一次验证用的密码进行请求：
C:\FreeRADIUS.net\bin>radclient.exe -d ..\etc\raddb -f radtest.txt -x -s 127.1 auth testing123
Sending Access-Request of id 172 to 127.0.0.1 port 1812
User-Name = "admin"
User-Password = "test"
NAS-IP-Address = 127.0.0.1
NAS-Port = 123
rad_recv: Access-Challenge packet from host 127.0.0.1:1812, id=172, length=63
User-Name = "admin"
User-Password = "test"
NAS-IP-Address = 127.0.0.1
NAS-Port = 123
Reply-Message = "PFJT"
Total approved auths: 1
Total denied auths: 0
Total lost auths: 0
PS C:\FreeRADIUS.net\bin> .\radtest.bat
收到了应答，里面带了挑战码
#使用挑战码去请求：
C:\FreeRADIUS.net\bin>radclient.exe -d ..\etc\raddb -f radtest.txt -x -s 127.1 auth testing123
Sending Access-Request of id 0 to 127.0.0.1 port 1812
User-Name = "admin"
User-Password = "PFJT"
NAS-IP-Address = 127.0.0.1
NAS-Port = 123
rad_recv: Access-Accept packet from host 127.0.0.1:1812, id=0, length=57
User-Name = "admin"
User-Password = "PFJT"
NAS-IP-Address = 127.0.0.1
NAS-Port = 123
Total approved auths: 1
Total denied auths: 0
Total lost auths: 0
PS C:\FreeRADIUS.net\bin> .\radtest.bat
第二次使用挑战码请求，挑战码已经失效，应该请求失败：
C:\FreeRADIUS.net\bin>radclient.exe -d ..\etc\raddb -f radtest.txt -x -s 127.1 auth testing123
Sending Access-Request of id 196 to 127.0.0.1 port 1812
User-Name = "admin"
User-Password = "PFJT"
NAS-IP-Address = 127.0.0.1
NAS-Port = 123
rad_recv: Access-Reject packet from host 127.0.0.1:1812, id=196, length=57
User-Name = "admin"
User-Password = "PFJT"
NAS-IP-Address = 127.0.0.1
NAS-Port = 123
Total approved auths: 0
Total denied auths: 1
Total lost auths: 0
再改进一下，回应的报文中少点请求的属性。
from pyrad import *
import socket
import pyrad.host
import random
BUFSIZE = 1024
KEY = b"testing123"
CHALLENGE = "test2"
class RadiusServer(pyrad.host.Host):
def __init__(self):
dict = pyrad.dictionary.Dictionary("dictionary.rfc2865") #从freeradius中搞一个通用的字典使用
pyrad.host.Host.__init__(self, dict=dict)
def get_challenge(self): #产生一个4字节的随机挑战码
challenge = ""
challenge = challenge + str(chr(random.randint(65,90)))
challenge = challenge + str(chr(random.randint(65,90)))
challenge = challenge + str(chr(random.randint(65,90)))
challenge = challenge + str(chr(random.randint(65,90)))
return challenge
def check_pass(self, radpkt, get_pw): #检查用户名密码，这里简单处理一下，如果密码是test则发起挑战，如果输入正确的挑战码，回应正确，否则失败
global CHALLENGE
print("check user")
pwd = ""
if 1 == get_pw:
pwd = radpkt["User-Password"][0]
if radpkt.PwCrypt(CHALLENGE) == pwd:
radpkt.code = packet.AccessAccept
CHALLENGE = self.get_challenge() #挑战码使用过后就更换掉
print("AccessAccept")
elif radpkt.PwCrypt("test") == pwd:
radpkt.code = packet.AccessChallenge
CHALLENGE = self.get_challenge()
radpkt.AddAttribute("Reply-Message", CHALLENGE) #把挑战码发给客户端
print("AccessChallenge， please input", CHALLENGE)
else:
radpkt.code = packet.AccessReject
print("AccessReject")
def get_pkt(self, pkt):
get_pw = None
get_name = None
radpkt = self.CreateAuthPacket(packet=pkt) #解析请求报文
print("code:", radpkt.code)
print("authenticator:", radpkt.authenticator)
print("id:", radpkt.id)
#radpkt.code = packet.AccessChallenge
radpkt.secret = KEY
for key in radpkt.keys():
print(key, radpkt[key])
if key == "User-Password":
get_pw = 1
if key == "User-Name":
get_name = 1
if 1 == get_pw and 1 == get_name:
self.check_pass(radpkt, get_pw)
reply = radpkt.CreateReply()
for key in radpkt.keys():
if key == "User-Name":
reply.AddAttribute("User-Name", radpkt["User-Name"][0])
if key == "Reply-Message":
reply.AddAttribute("Reply-Message", radpkt["Reply-Message"][0])
if key == "NAS-IP-Address":
reply.AddAttribute("NAS-IP-Address", radpkt["NAS-IP-Address"][0])
#reply.source = radpkt.source
reply.code = radpkt.code
return reply.ReplyPacket()
ip_port = ('', 1812)
server = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) # udp协议
server.bind(ip_port)
while True:
data,client_addr = server.recvfrom(BUFSIZE)
srv = RadiusServer()
reply = srv.get_pkt(data)
server.sendto(reply, client_addr)
测试:
PS C:\FreeRADIUS.net\bin> .\radclient.exe -d ..\etc\raddb -f radtest.txt -x -s 127.0.0.1 auth testing123
Sending Access-Request of id 48 to 127.0.0.1 port 1812
User-Name = "admin"
User-Password = "test"
NAS-IP-Address = 127.0.0.1
NAS-Port = 123
rad_recv: Access-Challenge packet from host 127.0.0.1:1812, id=48, length=39
User-Name = "admin"
NAS-IP-Address = 127.0.0.1
Reply-Message = "UTJG"
Total approved auths: 1
Total denied auths: 0
Total lost auths: 0
PS C:\FreeRADIUS.net\bin> .\radclient.exe -d ..\etc\raddb -f radtest.txt -x -s 127.0.0.1 auth testing123
Sending Access-Request of id 228 to 127.0.0.1 port 1812
User-Name = "admin"
User-Password = "UTJG"
NAS-IP-Address = 127.0.0.1
NAS-Port = 123
rad_recv: Access-Accept packet from host 127.0.0.1:1812, id=228, length=33
User-Name = "admin"
NAS-IP-Address = 127.0.0.1
Total approved auths: 1
Total denied auths: 0
Total lost auths: 0