运行一个临时的DNS Server

运行一个临时的DNS Server

在配置文件里把文件/目录地址改到当前目录下。BIND 9.7多了一个session-keyfile。

#!/usr/bin/env bash



ROOT="$(pwd)"



mkdir -p "${ROOT}/keys"

mkdir -p "${ROOT}/zones"



if [[ ! -e "named.conf" ]]; then



cat >"named.conf" << EOF

options {

        listen-on               port 8053       { 127.0.0.1; };

        directory               "${ROOT}/zones";

        pid-file                "${ROOT}/named.pid";

        session-keyfile         "${ROOT}/session.key";

        managed-keys-directory  "${ROOT}/keys";



        allow-query             { 127.0.0.1; };

        recursion               no;

};



controls {};

EOF



fi



named -c named.conf -g

添加一个zone

修改named.conf，添加一个zone。

zone "example.com." {

        type    master;

        file    "example.com";

};

在zones目录下，新建example.com文件

$ORIGIN .

$TTL 300

example.com     IN SOA  example.com. root.example.com. (

                201208061  ; serial

                300        ; refresh

                300        ; retry

                300        ; expire

                300        ; minimum

                )

            NS  ns.example.com.

            A   127.0.0.1

ns.example.com.     A   127.0.0.1

使用dig来查询

console $ dig -p 8053 @127.0.0.1 example.com

; <<>> DiG 9.8.2-RedHat-9.8.2-1.fc16 <<>> -p 8053 @127.0.0.1 example.com ; (1 server found) ;; GLOBAL OPTIONS: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 2269 ;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 1 ;; WARNING: recursion requested but not available

;; QUESTION SECTION: ;example.com. IN A

;; ANSWER SECTION: example.com. 300 IN A 127.0.0.1

;; AUTHORITY SECTION: example.com. 300 IN NS ns.example.com.

;; ADDITIONAL SECTION: ns.example.com. 300 IN A 127.0.0.1

;; Query time: 1 msec ;; SERVER: 127.0.0.1#8053(127.0.0.1) ;; WHEN: Mon Aug 6 16:35:14 2012 ;; MSG SIZE rcvd: 78

 

修改DNS记录

修改zone的设置，添加allow-update。因为BIND 9.7开始，BIND启动的时候会临时生成一个可以用来update的key。就先用这个key来操作好了。

zone "example.com." {

        type            master;

        file            "example.com";



        allow-update    { key local-ddns; };

};

用nsupdate添加一条记录

console $ nsupdate -k session.key

server localhost 8053 update add www.example.com. 300 A 127.0.0.1 send quit $

用dig查询结果

console $ dig -p 8053 @127.0.0.1 www.example.com

; <<>> DiG 9.8.2-RedHat-9.8.2-1.fc16 <<>> -p 8053 @127.0.0.1 www.example.com ; (1 server found) ;; GLOBAL OPTIONS: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 40774 ;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 1 ;; WARNING: recursion requested but not available

;; QUESTION SECTION: ;www.example.com. IN A

;; ANSWER SECTION: www.example.com. 300 IN A 127.0.0.1

;; AUTHORITY SECTION: example.com. 300 IN NS ns.example.com.

;; ADDITIONAL SECTION: ns.example.com. 300 IN A 127.0.0.1

;; Query time: 2 msec ;; SERVER: 127.0.0.1#8053(127.0.0.1) ;; WHEN: Mon Aug 6 16:47:02 2012 ;; MSG SIZE rcvd: 82

 

删除一条记录可以用

format text_markdown

update delete www.example.com. 300 A 127.0.0.1

要一次删除www.example.com.所有A记录，用

update delete www.example.com. A

生成修改记录用的key

console $ dnssec-keygen -T KEY -a HMAC-SHA512 -b 512 -n USER user Kuser.+165+40835 $ cat Kuser.+165+40835.key user. IN KEY 0 3 165 C25Jqxj2ZY8m18yaANh9FpvKhHPXksoOtlOH8XemcV4YB4JSfmbqEmbf lpZIBgeTHqPkMNv08jbyluawecL5yA== $ cat Kuser.+165+40835.private Private-key-format: v1.3 Algorithm: 165 (HMAC_SHA512) Key: C25Jqxj2ZY8m18yaANh9FpvKhHPXksoOtlOH8XemcV4YB4JSfmbqEmbflpZIBgeTHqPkMNv08jbyluawecL5yA== Bits: AAA= Created: 20120807063255 Publish: 20120807063255 Activate: 20120807063255

修改named.conf

key "user." {

        algorithm       HMAC-SHA512;

        secret          "C25Jqxj2ZY8m18yaANh9FpvKhHPXksoOtlOH8XemcV4YB4JSfmbqEmbflpZIBgeTHqPkMNv08jbyluawecL5yA==";

};



zone "example.com." {

        type            master;

        file            "example.com";



        allow-update    { key user.; };

};

此时用nsupdate -k Kuser.+165+40835.private就可以修改DNS记录了

Python

可以用dnspython来修改DNS记录

python

import dns.query

import dns.tsig

import dns.tsigkeyring

import dns.update

import dns.rdatatype



keyring = dns.tsigkeyring.from_text({

    'user.': "C25Jqxj2ZY8m18yaANh9FpvKhHPXksoOtlOH8XemcV4YB4JSfmbqEmbflpZIBgeTHqPkMNv08jbyluawecL5yA=="

})



update = dns.update.Update(

    'example.com.', 

    keyring=keyring,

    keyalgorithm=dns.tsig.HMAC_SHA512)



update.add('www', 300, dns.rdatatype.A, '127.0.0.1')



response = dns.query.tcp(update, '127.0.0.1', port=8053)

print response

运行

$ python dnsupdate.py

id 49584

opcode UPDATE

rcode NOERROR

flags QR

;ZONE

example.com. IN SOA

;PREREQ

;UPDATE

;ADDITIONAL

Java

可以用dnsjava来修改DNS记录

import org.xbill.DNS.*;



class DNSUpdate {

    public static void main(String args[]) throws org.xbill.DNS.TextParseException, java.io.IOException {

        Name zone = Name.fromString("example.com.");

        Update update = new Update(zone);

        Name host = Name.fromString("www", zone);

        TSIG key = new TSIG(

            TSIG.HMAC_SHA512,

            "user.",

            "C25Jqxj2ZY8m18yaANh9FpvKhHPXksoOtlOH8XemcV4YB4JSfmbqEmbflpZIBgeTHqPkMNv08jbyluawecL5yA==");



        update.add(host, Type.A, 300, "127.0.0.1");



        Resolver resolver = new SimpleResolver("127.0.0.1");

        resolver.setTCP(true);

        resolver.setPort(8053);

        resolver.setTSIGKey(key);



        Message response = resolver.send(update);



        System.out.println(response);

    }

};

编译运行

$ javac -cp dnsjava-2.1.3.jar DNSUpdate.java

$ java -cp .:dnsjava-2.1.3.jar DNSUpdate

;; ->>HEADER<<- opcode: UPDATE, status: NOERROR, id: 54821

;; flags: qr ; qd: 1 an: 0 au: 0 ad: 1

;; TSIG ok

;; ZONE:

;;      example.com., type = SOA, class = IN



;; PREREQUISITES:



;; UPDATE RECORDS:



;; ADDITIONAL RECORDS:

user.                   0       ANY     TSIG    hmac-sha512. 1344326060 300 64 YmqR2FI00zkP+K8oikeip7QM+QSZgAJg/b+vCCFi18AFFarRdOrkNSRNouPMGec9qUko0Gf6AywU2W7YXsKUtA== NOERROR 0



;; Message size: 138 bytes

Master/Slave

修改zone的设置，添加allow-transfer和also-notify。

zone "example.com." {

        type            master;

        file            "example.com";



        allow-update    { key local-ddns; };

        allow-transfer  { 127.0.0.1; };

        also-notify     { 127.0.0.1 port 8153; };

};

slave的配置，只要把zone的masters设置好就可以了。

#!/usr/bin/env bash



ROOT="$(pwd)"



mkdir -p "${ROOT}/slave-keys"

mkdir -p "${ROOT}/slave-zones"



if [[ ! -e "slave.conf" ]]; then



cat >"slave.conf" << EOF

options {

        listen-on               port 8153       { 127.0.0.1; };

        directory               "${ROOT}/slave-zones";

        pid-file                "${ROOT}/slave.pid";        

        session-keyfile         "${ROOT}/slave.session.key";

        managed-keys-directory  "${ROOT}/slave-keys";        



        allow-query             { 127.0.0.1; };

        recursion               no;

};



controls {};



zone "example.com." {

        type    slave;

        masters { 127.0.0.1 port 8053; };

};

EOF



fi



named -c slave.conf -g

DNSSEC

在zones目录下，生成ZSK

$ dnssec-keygen -a rsasha512 -b 1024 -n ZONE example.com.

Generating key pair......................++++++ ...............++++++ 

Kexample.com.+010+41861

生成KSK

$ dnssec-keygen -a rsasha512 -b 1024 -n ZONE -f KSK example.com.

Generating key pair.........................++++++ .....................................++++++ 

Kexample.com.+010+49764

修改example.com，在最后添加两行

$INCLUDE "Kexample.com.+010+41861.key"

$INCLUDE "Kexample.com.+010+49764.key"

签名zone

$ dnssec-signzone example.com

Verifying the zone using the following algorithms: RSASHA512.

Zone signing complete:

Algorithm: RSASHA512: KSKs: 1 active, 0 stand-by, 0 revoked

                      ZSKs: 1 active, 0 stand-by, 0 revoked

example.com.signed

修改named.conf

zone "example.com." {

        type            master;

        file            "example.com.signed";

};

在options加上

        dnssec-enable           yes;

启动bind，查看DNSKEY

$ dig -p 8053 @localhost  +multi +noall +answer DNSKEY example.com.

example.com.            300 IN DNSKEY 256 3 10 (

                                AwEAAbexLhdu6Fk91XVCZlXPuJUD4BfigFUFhEkijwrF

                                CF6KCAuixIt4tob2l4yTw/txAbGuzNz5t4oI/GUifniJ

                                oQO5WLn18YnhPtQ/TLgyDfTB01IAqK1AMNJ4bHINEn4V

                                gh3q4V41xgh8GMdYN5LsD5qUKUpoy8hMLRSGSK6VVr6v

                                ) ; key id = 41861

example.com.            300 IN DNSKEY 257 3 10 (

                                AwEAAboBxp1wNbmxhINtxORCNfwQQaZ3QlTtlxfV+jCR

                                Y5R44ri1ygI5kZEToqiB7W6nnxbUi9T5HRGmJmprl7Qa

                                pEzw4S8YaUXCdYAPy8tNFHMSsrj2d72r2gR2DSBp4C5Z

                                D5XGdk9kV6GSbCl0DMd0nzabSLMVw/A8N7l9cVU+MVez

                                ) ; key id = 49764

建立trusted-key.key文件

example.com.            300 IN DNSKEY 257 3 10 AwEAAboBxp1wNbmxhINtxORCNfwQQaZ3QlTtlxfV+jCRY5R44ri1ygI5kZEToqiB7W6nnxbUi9T5HRGmJmprl7QapEzw4S8YaUXCdYAPy8tNFHMSsrj2d72r2gR2DSBp4C5ZD5XGdk9kV6GSbCl0DMd0nzabSLMVw/A8N7l9cVU+MVez

用dig来验证

$ dig -p 8053 @localhost A example.com. +sigchase +trusted-key=trusted-key.key

;; RRset to chase:

example.com.            300     IN      A       127.0.0.1



;; RRSIG of the RRset to chase:

example.com.            300     IN      RRSIG   A 10 2 300 20120909052125 20120810052125 41861 example.com. A5raSwawZlfWejUvvWG+DYTiAMhbWyTXyScEYNxJxSyOrzZGLD4gGlFI RGmt91nmyw2+f2sHHqlRtvEmcxzFydTwZJs0lTdkQ3PODov4btEah52N aJGADObHaIAqZYcvYPlIpDDcZNIDQxbJbQyI6+JmWoFJN4QwyqXLn9dr LTU=







Launch a query to find a RRset of type DNSKEY for zone: example.com.



;; DNSKEYset that signs the RRset to chase:

example.com.            300     IN      DNSKEY  256 3 10 AwEAAbexLhdu6Fk91XVCZlXPuJUD4BfigFUFhEkijwrFCF6KCAuixIt4 tob2l4yTw/txAbGuzNz5t4oI/GUifniJoQO5WLn18YnhPtQ/TLgyDfTB 01IAqK1AMNJ4bHINEn4Vgh3q4V41xgh8GMdYN5LsD5qUKUpoy8hMLRSG SK6VVr6v

example.com.            300     IN      DNSKEY  257 3 10 AwEAAboBxp1wNbmxhINtxORCNfwQQaZ3QlTtlxfV+jCRY5R44ri1ygI5 kZEToqiB7W6nnxbUi9T5HRGmJmprl7QapEzw4S8YaUXCdYAPy8tNFHMS srj2d72r2gR2DSBp4C5ZD5XGdk9kV6GSbCl0DMd0nzabSLMVw/A8N7l9 cVU+MVez





;; RRSIG of the DNSKEYset that signs the RRset to chase:

example.com.            300     IN      RRSIG   DNSKEY 10 2 300 20120909052125 20120810052125 41861 example.com. KEAnlTPJsxS1lg4vJv3MdblH9LgPq5Mcv5uxhjnujHiyJkPw9kl57lcp GyFOZcWcE226fBoM+YkzHhziiPmTnjxZBWK9unnsyBgfsGy+t6YlvorQ XB60O0AAgrbDouWg9HO3wpYjILXK37w/J+MkCYXPpj1o5+OU5Adtl/LK HJQ=

example.com.            300     IN      RRSIG   DNSKEY 10 2 300 20120909052125 20120810052125 49764 example.com. V1fqbwK/USLsnHN2Q6tgN4mFMZtaEjtbhkSzUCPDq6TFsOEClHF09Do7 0mEDQCqW+r1DljpAPVzHBHzzKz5DAMLApn+qVeE+NaD0/WvMeh5nyvMQ 8jQ0102M7i9bVuRvnfSKRU74UxWD71Py6AS6wyg26KBgP9RIs4f5UEeN lPc=







Launch a query to find a RRset of type DS for zone: example.com.

;; NO ANSWERS: no more



;; WARNING There is no DS for the zone: example.com.







;; WE HAVE MATERIAL, WE NOW DO VALIDATION

;; VERIFYING A RRset for example.com. with DNSKEY:41861: success

;; OK We found DNSKEY (or more) to validate the RRset

;; Ok, find a Trusted Key in the DNSKEY RRset: 49764

;; VERIFYING DNSKEY RRset for example.com. with DNSKEY:49764: success



;; Ok this DNSKEY is a Trusted Key, DNSSEC validation is ok: SUCCESS

recursive resolver

建立trusted-keys文件

trusted-keys {

example.com.            257 3 10 "AwEAAboBxp1wNbmxhINtxORCNfwQQaZ3QlTtlxfV+jCRY5R44ri1ygI5kZEToqiB7W6nnxbUi9T5HRGmJmprl7QapEzw4S8YaUXCdYAPy8tNFHMSsrj2d72r2gR2DSBp4C5ZD5XGdk9kV6GSbCl0DMd0nzabSLMVw/A8N7l9cVU+MVez";

};

bind

启动bind作为recursive resolver

#!/usr/bin/env bash



ROOT="$(pwd)"



mkdir -p "${ROOT}/recursive-keys"

mkdir -p "${ROOT}/recursive-zones"



if [[ ! -e "recursive.conf" ]]; then



cat >"recursive.conf" << EOF

options {

        listen-on               port 8253       { 127.0.0.1; };

        directory               "${ROOT}/recursive-zones";

        pid-file                "${ROOT}/recursive.pid";

        session-keyfile         "${ROOT}/recursive.session.key";

        managed-keys-directory  "${ROOT}/recursive-keys";



        allow-query             { 127.0.0.1; };

        recursion               yes;

        dnssec-validation       yes;        

        forwarders { 127.0.0.1 port 8053; };

};



controls {};



include "${ROOT}/trusted-keys";

EOF



fi



named -c recursive.conf -g

使用dig查看结果

$ dig -p 8253 @localhost example.com. +dnssec



; <<>> DiG 9.8.2-RedHat-9.8.2-1.fc16 <<>> -p 8253 @localhost example.com. +dnssec

; (1 server found)

;; global options: +cmd

;; Got answer:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 29620

;; flags: qr rd ra ad; QUERY: 1, ANSWER: 2, AUTHORITY: 2, ADDITIONAL: 1



;; OPT PSEUDOSECTION:

; EDNS: version: 0, flags: do; udp: 4096

;; QUESTION SECTION:

;example.com.                   IN      A



;; ANSWER SECTION:

example.com.            78      IN      A       127.0.0.1

example.com.            78      IN      RRSIG   A 10 2 300 20120909052125 20120810052125 41861 example.com. A5raSwawZlfWejUvvWG+DYTiAMhbWyTXyScEYNxJxSyOrzZGLD4gGlFI RGmt91nmyw2+f2sHHqlRtvEmcxzFydTwZJs0lTdkQ3PODov4btEah52N aJGADObHaIAqZYcvYPlIpDDcZNIDQxbJbQyI6+JmWoFJN4QwyqXLn9dr LTU=



;; AUTHORITY SECTION:

example.com.            78      IN      NS      ns.example.com.

example.com.            78      IN      RRSIG   NS 10 2 300 20120909052125 20120810052125 41861 example.com. JMTkJtNQ75fRhHY+QgMqkVChHKAOiV+tnG3YiEKEBVmgBoslNaCdTFvw PJXfxCh776Nl+o5xbNkA6nZNcAA6UlM8/v9piK5+K1as7n5MJTiIDacC KiHYIwZvBrs8F3OVybXV+rTshFz4t19NNx8snJD9yP+UJLjmxV3Ej0OP QKo=



;; Query time: 1 msec

;; SERVER: 127.0.0.1#8253(127.0.0.1)

;; WHEN: Fri Aug 10 15:39:16 2012

;; MSG SIZE  rcvd: 415

unbound

启动unbound作为recursive resolver

#!/usr/bin/env bash



ROOT="$(pwd)"





if [[ ! -e "unbound.conf" ]]; then



cat >"unbound.conf" << EOF

server:

    num-threads: 1

    port: 8353

    directory: "${ROOT}"

    trusted-keys-file: "${ROOT}/trusted-keys"

    pidfile: "${ROOT}/unbound.pid"

    verbosity: 1

    use-syslog: no

    do-daemonize: no

    username: "$(whoami)"

    do-not-query-localhost: no





forward-zone:

    name: "example.com."

    forward-addr: 127.0.0.1@8053

EOF



fi



unbound -c unbound.conf

使用dig查看结果

$ dig -p 8353 @localhost example.com. +dnssec



; <<>> DiG 9.8.2-RedHat-9.8.2-1.fc16 <<>> -p 8353 @localhost example.com. +dnssec

; (1 server found)

;; global options: +cmd

;; Got answer:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 28672

;; flags: qr rd ra ad; QUERY: 1, ANSWER: 2, AUTHORITY: 2, ADDITIONAL: 3



;; OPT PSEUDOSECTION:

; EDNS: version: 0, flags: do; udp: 4096

;; QUESTION SECTION:

;example.com.                   IN      A



;; ANSWER SECTION:

example.com.            300     IN      A       127.0.0.1

example.com.            300     IN      RRSIG   A 10 2 300 20120909052125 20120810052125 41861 example.com. A5raSwawZlfWejUvvWG+DYTiAMhbWyTXyScEYNxJxSyOrzZGLD4gGlFI RGmt91nmyw2+f2sHHqlRtvEmcxzFydTwZJs0lTdkQ3PODov4btEah52N aJGADObHaIAqZYcvYPlIpDDcZNIDQxbJbQyI6+JmWoFJN4QwyqXLn9dr LTU=



;; AUTHORITY SECTION:

example.com.            300     IN      NS      ns.example.com.

example.com.            300     IN      RRSIG   NS 10 2 300 20120909052125 20120810052125 41861 example.com. JMTkJtNQ75fRhHY+QgMqkVChHKAOiV+tnG3YiEKEBVmgBoslNaCdTFvw PJXfxCh776Nl+o5xbNkA6nZNcAA6UlM8/v9piK5+K1as7n5MJTiIDacC KiHYIwZvBrs8F3OVybXV+rTshFz4t19NNx8snJD9yP+UJLjmxV3Ej0OP QKo=



;; ADDITIONAL SECTION:

ns.example.com.         300     IN      A       127.0.0.1

ns.example.com.         300     IN      RRSIG   A 10 3 300 20120909052125 20120810052125 41861 example.com. MgDjvx9Xmfg/p872Im2QhRgehKZi8yKr8E8dfueT+uhfp5KCx0g6pIX4 5VLJO/lYmdaG+vRQyj0FLTLntDIM9G/5rlKp9CISH4yD6nsyfQI63FM1 lwDM29fytCilHXvgWb64jbGf/lHxuKsaZjsvaJyRZeWyEzpFKNq8BB5v RHI=



;; Query time: 1 msec

;; SERVER: 127.0.0.1#8353(127.0.0.1)

;; WHEN: Fri Aug 10 15:48:40 2012

;; MSG SIZE  rcvd: 602

SSHFP

生成SSH密钥对

$ ssh-keygen -q -N '' -f id_rsa

转换成SSHFP记录，并把这行添加到zones/example.com里

$ ssh-keygen -r example.com. -f id_rsa.pub 

example.com. IN SSHFP 1 1 5727cac5dcca0d87c2b74f33e6e6106f09a03d27

SSH客户端使用的config文件

Host example.com

    Port 8022

    VerifyHostKeyDNS yes

    StrictHostKeyChecking ask

运行一个临时的SSH Server

#!/usr/bin/env python2



from twisted.python import log

import sys

log.startLogging(sys.stderr)



from twisted.internet import reactor

from twisted.conch.ssh import factory

from twisted.conch.ssh import keys



SSHD_KEY = 'id_rsa'



PUBLIC_KEY = keys.Key.fromFile(SSHD_KEY)

PRIVATE_KEY = keys.Key.fromFile(SSHD_KEY)



SSH_TYPE = PUBLIC_KEY.sshType()

FINGERPRINT = PUBLIC_KEY.fingerprint()



class SSHFactory(factory.SSHFactory):

    publicKeys = {SSH_TYPE: PUBLIC_KEY}

    privateKeys = {SSH_TYPE: PRIVATE_KEY}





reactor.listenTCP(8022, SSHFactory())

reactor.run()

劫持SSH客户端的DNS请求，将其发往8253端口

#include 

#include 

#include 

#include 

#include 



#include 

#include 

#define __USE_GNU

#include 





static in_port_t sendto_port = 0;

static in_addr_t sendto_addr = INADDR_NONE;



int connect(int sockfd, const struct sockaddr *addr, socklen_t addrlen) {

  static int (*_connect)(int sockfd, const struct sockaddr *addr, socklen_t addrlen) = NULL;

  if (!_connect) _connect = dlsym(RTLD_NEXT, "connect");

  struct sockaddr_in *addr_in = (struct sockaddr_in *)addr;

  if (ntohs(addr_in->sin_port) != 53) return _connect(sockfd, addr, addrlen);



  struct sockaddr_in new_addr_in = {

    .sin_family = addr_in->sin_family,

    .sin_port = htons(8253),

    .sin_addr = { .s_addr = htonl(INADDR_LOOPBACK) },

    .sin_zero = {0,0,0,0,0,0,0,0},

  };



  sendto_addr = addr_in->sin_addr.s_addr;

  sendto_port = addr_in->sin_port;



  return _connect(sockfd, (struct sockaddr *)&new_addr_in, sizeof(new_addr_in));

}



ssize_t recvfrom(int sockfd, void *buf, size_t len, int flags, struct sockaddr *src_addr, socklen_t *addrlen) {

  static ssize_t (*_recvfrom)(int sockfd, void *buf, size_t len, int flags, struct sockaddr *src_addr, socklen_t *addrlen) = NULL;

  if (!_recvfrom) _recvfrom = dlsym(RTLD_NEXT, "recvfrom");



  ssize_t result = _recvfrom(sockfd, buf, len, flags, src_addr, addrlen);

  ((struct sockaddr_in *)src_addr)->sin_addr.s_addr = sendto_addr;

  ((struct sockaddr_in *)src_addr)->sin_port = sendto_port;

  return result;

}

编译，通过LD_PRELOAD运行SSH客户端

$ gcc -shared -fPIC -o hook.so hook.c -ldl

$ LD_PRELOAD="$(pwd)/hook.so" ssh -v -i id_rsa -F config example.com

OpenSSH_5.8p2, OpenSSL 1.0.0i-fips 19 Apr 2012

debug1: Reading configuration data config

debug1: Applying options for example.com

debug1: Connecting to example.com [127.0.0.1] port 8022.

debug1: Connection established.

debug1: identity file id_rsa type 1

debug1: identity file id_rsa-cert type -1

debug1: Remote protocol version 2.0, remote software version Twisted

debug1: no match: Twisted

debug1: Enabling compatibility mode for protocol 2.0

debug1: Local version string SSH-2.0-OpenSSH_5.8

debug1: SSH2_MSG_KEXINIT sent

debug1: SSH2_MSG_KEXINIT received

debug1: kex: server->client aes128-ctr hmac-md5 none

debug1: kex: client->server aes128-ctr hmac-md5 none

debug1: sending SSH2_MSG_KEXDH_INIT

debug1: expecting SSH2_MSG_KEXDH_REPLY

debug1: Server host key: RSA c4:04:b5:ef:1f:d3:0b:9a:44:13:a3:4e:e8:69:20:f2

debug1: found 1 secure fingerprints in DNS

debug1: matching host key fingerprint found in DNS

debug1: ssh_rsa_verify: signature correct

debug1: SSH2_MSG_NEWKEYS sent

debug1: expecting SSH2_MSG_NEWKEYS

debug1: SSH2_MSG_NEWKEYS received

debug1: Roaming not allowed by server

debug1: SSH2_MSG_SERVICE_REQUEST sent

Connection closed by 127.0.0.1

现在就不再提示需要确认服务端公钥了