本文为 SEED Labs 2.0 - Transport Layer Security (TLS) Lab 的实验记录。
文章目录
实验原理
现在越来越多的数据传输是通过互联网完成的。然而，当数据通过这种不受保护的公共网络传输时，它们可以被其他人读取甚至篡改。密码算法有很多种，即使是同一种算法，也有很多参数可以使用。为了实现互操作性，即允许不同的应用程序相互通信，这些应用程序需要遵循一个共同的标准。 TLS，Transport Layer Security，就是这样一个标准。如今，大多数 Web 服务器都使用 HTTPS，它建立在 TLS 之上。
本实验的目的是了解 TLS 的工作原理以及如何在编程中使用 TLS。我们实现一对TLS客户端和服务器程序，并在此基础上进行一系列实验，从而了解TLS协议底层的安全原理。我们还将实施一个简单的 HTTPS 代理程序，以了解如果某些受信任的 CA 遭到破坏时的安全影响。实验室涵盖以下主题：
• 公钥基础设施 (PKI)
• 传输层安全 (TLS)
• TLS 编程
• HTTPS 代理
• 扩展的 X.509 证书
• 中间人攻击
Task 1: TLS Client
Task 1.a: TLS handshake
编写代码 handshake.py：
#!/usr/bin/env python3import socketimport sslimport sysimport pprinthostname = sys.argv[1]port = 443cadir = '/etc/ssl/certs'#cadir = './client-certs'# Set up the TLS contextcontext = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT) # For Ubuntu 20.04 VM# context = ssl.SSLContext(ssl.PROTOCOL_TLSv1_2) # For Ubuntu 16.04 VMcontext.load_verify_locations(capath=cadir)context.verify_mode = ssl.CERT_REQUIREDcontext.check_hostname = True# Create TCP connectionsock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)sock.connect((hostname, port))input("After making TCP connection. Press any key to continue ...")# Add the TLSssock = context.wrap_socket(sock, server_hostname=hostname,do_handshake_on_connect=False)ssock.do_handshake() # Start the handshakeprint("=== Cipher used: {}".format(ssock.cipher()))print("=== Server hostname: {}".format(ssock.server_hostname))print("=== Server certificate:")pprint.pprint(ssock.getpeercert())pprint.pprint(context.get_ca_certs())input("After TLS handshake. Press any key to continue ...")# Close the TLS Connectionssock.shutdown(socket.SHUT_RDWR)ssock.close()这段代码的主要作用是先进行 TCP 握手，然后进行 TLS 连接，并输出相关信息。
我们使用它访问一下东南大学主页：
$ handshake.py https://blog.csdn.net/qq_39678161/article/details/www.seu.edu.cnAfter making TCP connection. Press any key to continue ...=== Cipher used: ('AES256-SHA', 'SSLv3', 256)=== Server hostname: https://blog.csdn.net/qq_39678161/article/details/www.seu.edu.cn=== Server certificate:{'OCSP': ('http://ocsp.digicert.cn',), 'caIssuers': ('http://cacerts.digicert.cn/GeoTrustRSACNCAG2.crt',), 'crlDistributionPoints': ('http://crl.digicert.cn/GeoTrustRSACNCAG2.crl',), 'issuer': ((('countryName', 'US'),), (('organizationName', 'DigiCert Inc'),), (('commonName', 'GeoTrust RSA CN CA G2'),)), 'notAfter': 'Jul 10 23:59:59 2023 GMT', 'notBefore': 'Jun 9 00:00:00 2022 GMT', 'serialNumber': '08102829656C723ABA92C1FA58F0E960', 'subject': ((('countryName', 'CN'),), (('stateOrProvinceName', '江苏省'),), (('localityName', '南京市'),), (('organizationName', '东南大学'),), (('commonName', '*.seu.edu.cn'),)), 'subjectAltName': (('DNS', '*.seu.edu.cn'), ('DNS', 'seu.edu.cn')), 'version': 3}[{'issuer': ((('countryName', 'US'),), (('organizationName', 'DigiCert Inc'),), (('organizationalUnitName', 'www.digicert.com'),), (('commonName', 'DigiCert Global Root CA'),)), 'notAfter': 'Nov 10 00:00:00 2031 GMT', 'notBefore': 'Nov 10 00:00:00 2006 GMT', 'serialNumber': '083BE056904246B1A1756AC95991C74A', 'subject': ((('countryName', 'US'),), (('organizationName', 'DigiCert Inc'),), (('organizationalUnitName', 'www.digicert.com'),), (('commonName', 'DigiCert Global Root CA'),)), 'version': 3}]After TLS handshake. Press any key to continue ...What is the cipher used between the client and the server?
=== Cipher used: ('AES256-SHA', 'SSLv3', 256)Please print out the server certificate in the program.
{'OCSP': ('http://ocsp.digicert.cn',), 'caIssuers': ('http://cacerts.digicert.cn/GeoTrustRSACNCAG2.crt',), 'crlDistributionPoints': ('http://crl.digicert.cn/GeoTrustRSACNCAG2.crl',), 'issuer': ((('countryName', 'US'),), (('organizationName', 'DigiCert Inc'),), (('commonName', 'GeoTrust RSA CN CA G2'),)), 'notAfter': 'Jul 10 23:59:59 2023 GMT', 'notBefore': 'Jun 9 00:00:00 2022 GMT', 'serialNumber': '08102829656C723ABA92C1FA58F0E960', 'subject': ((('countryName', 'CN'),), (('stateOrProvinceName', '江苏省'),), (('localityName', '南京市'),), (('organizationName', '东南大学'),), (('commonName', '*.seu.edu.cn'),)), 'subjectAltName': (('DNS', '*.seu.edu.cn'), ('DNS', 'seu.edu.cn')), 'version': 3}Explain the purpose of /etc/ssl/certs.
$ ls /etc/ssl/certs...... ACCVRAIZ1.pem AC_RAIZ_FNMT-RCM.pem Actalis_Authentication_Root_CA.pem AffirmTrust_Commercial.pem AffirmTrust_Networking.pem AffirmTrust_Premium.pem AffirmTrust_Premium_ECC.pem Amazon_Root_CA_1.pem Amazon_Root_CA_2.pem Amazon_Root_CA_3.pem Amazon_Root_CA_4.pem Atos_TrustedRoot_2011.pem......该文件夹中存储了验证证书所需的根 CA。
Use Wireshark to capture the network traffics during the execution of the program, and explain your observation. In particular, explain which step triggers the TCP handshake, and which step triggers the TLS handshake. Explain the relationship between the TLS handshake and the TCP handshake.
Wireshark 截图如下：
编号 3-5 的部分为 TCP 的三次握手。编号 6-13 的部分为 TLS 握手。客户端首先发送 Client Hello 信息，服务器回复 Server Hello。客户端验证后，发送密钥交换及更改密码规范消息，服务器回复更改密码规范消息。至此，TLS 握手完成，进行后续结束工作。
Task 1.b: CA’s Certificate
修改原程序中的：
cadir = './client-certs'然后再次运行：
$ handshake.py https://blog.csdn.net/qq_39678161/article/details/www.seu.edu.cnAfter making TCP connection. Press any key to continue ...Traceback (most recent call last): File "./handshake.py", line 29, in <module> ssock.do_handshake() # Start the handshake File "/usr/lib/python3.8/ssl.py", line 1309, in do_handshake self._sslobj.do_handshake()ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1123)可以看到，证书验证失败。这是因为没有找到对应的 CA 证书。
我们在之前有看到：
[{'issuer': ((('countryName', 'US'),), (('organizationName', 'DigiCert Inc'),), (('organizationalUnitName', 'www.digicert.com'),), (('commonName', 'DigiCert Global Root CA'),)),这里，表明了安全访问东南大学主页所需要的 CA 证书。所以我们需要找到这个证书并放进 client-certs 文件夹中：
$ ll /etc/ssl/certs | grep DigiCert_Global_Root_CAlrwxrwxrwx 1 root root 27 Nov 26 2020 3513523f.0 -> DigiCert_Global_Root_CA.pemlrwxrwxrwx 1 root root 62 Nov 26 2020 DigiCert_Global_Root_CA.pem -> /usr/share/ca-certificates/mozilla/DigiCert_Global_Root_CA.crt$ cp /usr/share/ca-certificates/mozilla/DigiCert_Global_Root_CA.crt client-certs/DigiCert_Global_Root_CA.crt我们同时需要修正证书的哈希并建立软链接：
$ cd client-certs$ openssl x509 -in DigiCert_Global_Root_CA.crt -noout -subject_hash3513523f$ ln -s DigiCert_Global_Root_CA.crt 3513523f.0$ lltotal 8lrwxrwxrwx 1 root root 27 Aug 11 07:50 3513523f.0 -> DigiCert_Global_Root_CA.crt-rw-r--r-- 1 root root 1338 Aug 11 07:44 DigiCert_Global_Root_CA.crt然后我们连接上了 https://blog.csdn.net/qq_39678161/article/details/www.seu.edu.cn：
$ handshake.py https://blog.csdn.net/qq_39678161/article/details/www.seu.edu.cn得到的结果与前文相同，此处不再重复粘贴。
我们尝试另一个使用不同证书的网站 https://blog.csdn.net/qq_39678161/article/details/codeforces.com：
$ handshake.py https://blog.csdn.net/qq_39678161/article/details/codeforces.comAfter making TCP connection. Press any key to continue ...=== Cipher used: ('TLS_AES_256_GCM_SHA384', 'TLSv1.3', 256)=== Server hostname: https://blog.csdn.net/qq_39678161/article/details/codeforces.com=== Server certificate:{'OCSP': ('http://r3.o.lencr.org',), 'caIssuers': ('http://r3.i.lencr.org/',), 'issuer': ((('countryName', 'US'),), (('organizationName', "Let's Encrypt"),), (('commonName', 'R3'),)), 'notAfter': 'Oct 5 08:10:08 2022 GMT', 'notBefore': 'Jul 7 08:10:09 2022 GMT', 'serialNumber': '04EE0F98910E33F9564658EF79DA9C2BA703', 'subject': ((('commonName', 'https://blog.csdn.net/qq_39678161/article/details/codeforces.com'),),), 'subjectAltName': (('DNS', '*.https://blog.csdn.net/qq_39678161/article/details/codeforces.com'), ('DNS', 'https://blog.csdn.net/qq_39678161/article/details/codeforces.com')), 'version': 3}[{'issuer': ((('countryName', 'US'),), (('organizationName', 'Internet Security Research Group'),), (('commonName', 'ISRG Root X1'),)), 'notAfter': 'Jun 4 11:04:38 2035 GMT', 'notBefore': 'Jun 4 11:04:38 2015 GMT', 'serialNumber': '8210CFB0D240E3594463E0BB63828B00', 'subject': ((('countryName', 'US'),), (('organizationName', 'Internet Security Research Group'),), (('commonName', 'ISRG Root X1'),)), 'version': 3}]After TLS handshake. Press any key to continue ...同样的，我们找到它的 CA 证书并做处理：
$ ll /etc/ssl/certs | grep ISRG_Root_X1 lrwxrwxrwx 1 root root 16 Nov 26 2020 4042bcee.0 -> ISRG_Root_X1.pemlrwxrwxrwx 1 root root 51 Nov 26 2020 ISRG_Root_X1.pem -> /usr/share/ca-certificates/mozilla/ISRG_Root_X1.crt$ cp /usr/share/ca-certificates/mozilla/ISRG_Root_X1.crt client-certs/ISRG_Root_X1.crt$ cd client-certs$ openssl x509 -in ISRG_Root_X1.crt -noout -subject_hash4042bcee$ ln -s ISRG_Root_X1.crt 4042bcee.0$ cd ..$ handshake.py https://blog.csdn.net/qq_39678161/article/details/codeforces.com得到的结果与前文相同，此处不再重复粘贴。
Task 1.c: Experiment with the hostname check
查看东南大学主页 ip：
$ dig https://blog.csdn.net/qq_39678161/article/details/www.seu.edu.cn; <<>> DiG 9.16.1-Ubuntu <<>> https://blog.csdn.net/qq_39678161/article/details/www.seu.edu.cn;; global options: +cmd;; Got answer:;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 56811;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1;; OPT PSEUDOSECTION:; EDNS: version: 0, flags:; udp: 65494;; QUESTION SECTION:;https://blog.csdn.net/qq_39678161/article/details/www.seu.edu.cn.INA;; ANSWER SECTION:https://blog.csdn.net/qq_39678161/article/details/www.seu.edu.cn.3600INCNAMEwidc142.seu.edu.cn.widc142.seu.edu.cn.3599INA58.192.118.142;; Query time: 4 msec;; SERVER: 127.0.0.53#53(127.0.0.53);; WHEN: Thu Aug 11 16:07:38 CST 2022;; MSG SIZE rcvd: 81修改 hosts：
$ sudo vi /etc/hosts依据之前看到的 ip，在 hosts 中添加：
58.192.118.142 www.nju.edu.cn修改程序，选择是否进行主机名称验证。当 context.check_hostname = True 时，有：
$ handshake.py www.nju.edu.cnAfter making TCP connection. Press any key to continue ...Traceback (most recent call last): File "./handshake.py", line 29, in <module> ssock.do_handshake() # Start the handshake File "/usr/lib/python3.8/ssl.py", line 1309, in do_handshake self._sslobj.do_handshake()ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: Hostname mismatch, certificate is not valid for 'www.nju.edu.cn'. (_ssl.c:1123)此时，证书验证失败，因为域名不一致。
而当 context.check_hostname = False 时，有：
$ handshake.py www.nju.edu.cnAfter making TCP connection. Press any key to continue ...=== Cipher used: ('AES256-SHA', 'SSLv3', 256)=== Server hostname: www.nju.edu.cn=== Server certificate:{'OCSP': ('http://ocsp.digicert.cn',), 'caIssuers': ('http://cacerts.digicert.cn/GeoTrustRSACNCAG2.crt',), 'crlDistributionPoints': ('http://crl.digicert.cn/GeoTrustRSACNCAG2.crl',), 'issuer': ((('countryName', 'US'),), (('organizationName', 'DigiCert Inc'),), (('commonName', 'GeoTrust RSA CN CA G2'),)), 'notAfter': 'Jul 10 23:59:59 2023 GMT', 'notBefore': 'Jun 9 00:00:00 2022 GMT', 'serialNumber': '08102829656C723ABA92C1FA58F0E960', 'subject': ((('countryName', 'CN'),), (('stateOrProvinceName', '江苏省'),), (('localityName', '南京市'),), (('organizationName', '东南大学'),), (('commonName', '*.seu.edu.cn'),)), 'subjectAltName': (('DNS', '*.seu.edu.cn'), ('DNS', 'seu.edu.cn')), 'version': 3}[{'issuer': ((('countryName', 'US'),), (('organizationName', 'DigiCert Inc'),), (('organizationalUnitName', 'www.digicert.com'),), (('commonName', 'DigiCert Global Root CA'),)), 'notAfter': 'Nov 10 00:00:00 2031 GMT', 'notBefore': 'Nov 10 00:00:00 2006 GMT', 'serialNumber': '083BE056904246B1A1756AC95991C74A', 'subject': ((('countryName', 'US'),), (('organizationName', 'DigiCert Inc'),), (('organizationalUnitName', 'www.digicert.com'),), (('commonName', 'DigiCert Global Root CA'),)), 'version': 3}]After TLS handshake. Press any key to continue ...这里就直接验证通过了。由此可见域名检查的重要性。
Task 1.d: Sending and getting Data
向上面的程序添加如下代码：
# Send HTTP Request to Serverrequest = b"GET / HTTP/1.0\r\nHost: " + \ hostname.encode('utf-8') + b"\r\n\r\n"ssock.sendall(request)# Read HTTP Response from Serverresponse = ssock.recv(2048)while response: pprint.pprint(response.split(b"\r\n")) response = ssock.recv(2048)Please add the data sending/receiving code to your client program, and report your observation.
执行：
$ handshake.py https://blog.csdn.net/qq_39678161/article/details/www.seu.edu.cn......After TLS handshake. Press any key to continue ...[b'HTTP/1.1 200 OK', b'Server: nginx/1.16.0', b'Date: Thu, 11 Aug 2022 08:41:06 GMT', b'Content-Type: text/html; charset=utf-8', b'Connection: close', b'X-Frame-Options: SAMEORIGIN', b'Frame-Options: SAMEORIGIN', b'Accept-Ranges: bytes', b'Vary: Accept-Encoding', b'Set-Cookie: NSC_xfcqmvt-02-iuuqt=ffffffff0948650745525d5f4f58455e445a4a42366' b'0;expires=Thu, 11-Aug-2022 09:01:08 GMT;path=/;secure;httponly', b'', b'', b'', ......可以看到，成功获取了东南大学主页的页面源码。
Please modify the HTTP request, so you can fetch an image file of your choice from an HTTPS server
我们尝试获取东南大学主页的校徽图片 https://https://blog.csdn.net/qq_39678161/article/details/www.seu.edu.cn/_upload/tpl/09/bc/2492/template2492/images/logo.png。
将 request 语句改为
request = b"GET /_upload/tpl/09/bc/2492/template2492/images/logo.png HTTP/1.0\r\nHost: " + hostname.encode('utf-8') + b"\r\n\r\n"运行效果如下
$ handshake.py https://blog.csdn.net/qq_39678161/article/details/www.seu.edu.cn......b'\x89PNG',b'\x1a\n\x00\x00\x00\rIHDR\x00\x00\x01\x11\x00\x00\x00X\x08\x06'b'\x00\x00\x00\xd2\xb4\xc3\x9e\x00\x00\x00\x19tEXtSoftware\x00Adobe ImageReady'b'q\xc9e<\x00\x00\x03!iTXtXML:com.adobe.xmp\x00\x00\x00\x00\x00b'n="\xef\xbb\xbf" id="W5M0MpCehiHzreSzNTczkc9d"?> 'e:ns:meta/" x:xmptk="Adobe XMP Core 5.5-c014 79.151481, 2013/03/13-12:09:15 ' b' "> ' b'b':xmpMM="http://ns.adobe.com/xap/1.0/mm/" xmlns:stRef="http://ns.adobe.com/xa'b'p/1.0/sType/ResourceRef#" xmp:CreatorTool="Adobe Photoshop CC (Windows)" xmp'b'MM:InstanceID="xmp.iid:67B7F0CEECC111EA929DA69D6D87DD17" xmpMM:DocumentID="x'b'mp.did:67B7F0CFECC111EA929DA69D6D87DD17"> b'D="xmp.iid:67B7F0CCECC111EA929DA69D6D87DD17" stRef:documentID="xmp.did:67B7F'b'0CDECC111EA929DA69D6D87DD17"/> b'xpacket end="r"?>\x9d\xc3\x8e\'\x00\x00/@IDATx\xda\xec\x9d\x07\xb4\x14'b'\xc5\xd2\xc7\x9bx\xb9H\x14P\xb2\x80D%\x07\x05\x14PQ\x9f\x19\x10\xb3\x82\x8a'b'\x19\x0c\x18\x9e\x8a\xa0(>\x10#\n&T\x0c(\xfa\xcc\x01\xb3"(\xa8\x88\x08'......可以看出，我们成功爬取到了图片。
Task 2: TLS Server
准备好 PKI 实验中得到的 server.crt 和 server.key，放入 server-certs 文件夹中。
将 ca.crt 放入 client-certs 文件夹中，并建立软链接：
$ openssl x509 -in ca.crt -noout -subject_hashdbb9c584$ ln -s ca.crt dbb9c584.0Task 2.a. Implement a simple TLS server
修改 handshake.py；
#!/usr/bin/env python3import socketimport sslimport sysimport pprinthostname = sys.argv[1]port = 4433#cadir = '/etc/ssl/certs'cadir = './client-certs'# Set up the TLS contextcontext = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT) # For Ubuntu 20.04 VM# context = ssl.SSLContext(ssl.PROTOCOL_TLSv1_2) # For Ubuntu 16.04 VMcontext.load_verify_locations(capath=cadir)context.verify_mode = ssl.CERT_REQUIREDcontext.check_hostname = True# Create TCP connectionsock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)sock.connect((hostname, port))input("After making TCP connection. Press any key to continue ...")# Add the TLSssock = context.wrap_socket(sock, server_hostname=hostname,do_handshake_on_connect=False)ssock.do_handshake() # Start the handshakeprint("=== Cipher used: {}".format(ssock.cipher()))print("=== Server hostname: {}".format(ssock.server_hostname))print("=== Server certificate:")pprint.pprint(ssock.getpeercert())pprint.pprint(context.get_ca_certs())input("After TLS handshake. Press any key to continue ...")# Close the TLS Connectionssock.shutdown(socket.SHUT_RDWR)ssock.close()编写 server.py：
#!/usr/bin/env python3import socketimport sslimport pprinthtml = """HTTP/1.1 200 OK\r\nContent-Type: text/html\r\n\r\nThis is Bank32.com!
"""SERVER_CERT = './server-certs/server.crt'SERVER_PRIVATE = './server-certs/server.key'context = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER) # For Ubuntu 20.04 VM# context = ssl.SSLContext(ssl.PROTOCOL_TLSv1_2) # For Ubuntu 16.04 VMcontext.load_cert_chain(SERVER_CERT, SERVER_PRIVATE)sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0)sock.bind(('0.0.0.0', 4433))sock.listen(5)while True: newsock, fromaddr = sock.accept() try: ssock = context.wrap_socket(newsock, server_side=True) print("TLS connection established") data = ssock.recv(1024) # Read data over TLS pprint.pprint("Request: {}".format(data)) ssock.sendall(html.encode('utf-8')) # Send data over TLS ssock.shutdown(socket.SHUT_RDWR) # Close the TLS connection ssock.close() except Exception: print("TLS connection fails") continue将 www.chenyang2022.com 加入到 client 容器的 hosts 中：
$ echo "10.9.0.43 www.chenyang2022.com" >> /etc/hosts在 server 上运行：
$ server.py在 client 上运行：
$ handshake.py www.chenyang2022.comserver 上得到：
Enter PEM pass phrase:TLS connection established"Request: b''"TLS connection failsclient 上得到：
After making TCP connection. Press any key to continue ...=== Cipher used: ('TLS_AES_256_GCM_SHA384', 'TLSv1.3', 256)=== Server hostname: www.chenyang2022.com=== Server certificate:{'issuer': ((('commonName', 'www.modelCA.com'),), (('organizationName', 'Model CA LTD.'),), (('countryName', 'US'),)), 'notAfter': 'Aug 6 02:42:42 2032 GMT', 'notBefore': 'Aug 9 02:42:42 2022 GMT', 'serialNumber': '1001', 'subject': ((('countryName', 'US'),), (('organizationName', 'Chenyang2022 Inc.'),), (('commonName', 'www.chenyang2022.com'),)), 'subjectAltName': (('DNS', 'www.chenyang2022.com'), ('DNS', 'www.chenyang2022A.com'), ('DNS', 'www.chenyang2022B.com')), 'version': 3}[{'issuer': ((('commonName', 'www.modelCA.com'),), (('organizationName', 'Model CA LTD.'),), (('countryName', 'US'),)), 'notAfter': 'Aug 6 02:40:07 2032 GMT', 'notBefore': 'Aug 9 02:40:07 2022 GMT', 'serialNumber': '2D814C6206ECC85CA0824B1FB708705CB060E83E', 'subject': ((('commonName', 'www.modelCA.com'),), (('organizationName', 'Model CA LTD.'),), (('countryName', 'US'),)), 'version': 3}]After TLS handshake. Press any key to continue ...可以看到，这里正常建立了连接。
而当 handshake.py 中改为 cadir = '/etc/ssl/certs' 后，结果为：
$ handshake.py www.chenyang2022.comAfter making TCP connection. Press any key to continue ...Traceback (most recent call last): File "./handshake.py", line 29, in <module> ssock.do_handshake() # Start the handshake File "/usr/lib/python3.8/ssl.py", line 1309, in do_handshake self._sslobj.do_handshake()ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1123)可以看到，正常建立了 TCP 连接，但无法建立 LTS。
Task 2.b. Testing the server program using browsers
由于我们在 PKI 实验中，已经在浏览器里添加了证书信任，故本次无需重复添加。
我们直接访问 https://www.chenyang2022.com:4433/，可以看到这是受信任的页面：
Task 2.c. Certificate with multiple names
编写 server_openssl.cnf
[ req ]prompt = nodistinguished_name = req_distinguished_namereq_extensions = req_ext[ req_distinguished_name ]C = USST = New YorkL = SyracuseO = Model CA LTD.CN = www.chenyang2022.com[ req_ext ]subjectAltName = @alt_names[alt_names]DNS.1 = www.chenyang2022.comDNS.2 = www.chenyang2020.comDNS.3 = *.chenyang2022.com这里，由于一些玄学的原因，我们不得不重新生成了 CA 并进行了相关操作，使得其 C、ST、L、O 均与上面的配置文件相同且不得为空。
$ openssl req -newkey rsa:2048 -config ./server_openssl.cnf -batch -sha256 -keyout server.key -out server.csr使用 CA 认证：
$ openssl ca -md sha256 -days 3650 -config ./myopenssl.cnf -batch -in server.csr -out server.crt -cert ca.crt -keyfile ca.key我们尝试定义的几个域名，得到：
$ server.pyEnter PEM pass phrase:TLS connection established"Request: b'GET / HTTP/1.0\\r\\nHost: www.chenyang2022.com\\r\\n\\r\\n'"TLS connection established"Request: b'GET / HTTP/1.0\\r\\nHost: www.chenyang2020.com\\r\\n\\r\\n'"TLS connection established"Request: b'GET / HTTP/1.0\\r\\nHost: love.chenyang2022.com\\r\\n\\r\\n'"$ handshake.py www.chenyang2022.com......$ handshake.py www.chenyang2020.com......$ handshake.py love.chenyang2022.comAfter making TCP connection. Press any key to continue ...=== Cipher used: ('TLS_AES_256_GCM_SHA384', 'TLSv1.3', 256)=== Server hostname: love.chenyang2022.com=== Server certificate:{'issuer': ((('commonName', 'www.modelCA.com'),), (('organizationName', 'Model CA LTD.'),), (('countryName', 'US'),), (('stateOrProvinceName', 'New York'),), (('localityName', 'Syracuse'),)), 'notAfter': 'Aug 8 16:59:10 2032 GMT', 'notBefore': 'Aug 11 16:59:10 2022 GMT', 'serialNumber': '2000', 'subject': ((('countryName', 'US'),), (('stateOrProvinceName', 'New York'),), (('organizationName', 'Model CA LTD.'),), (('commonName', 'www.chenyang2022.com'),)), 'subjectAltName': (('DNS', 'www.chenyang2022.com'), ('DNS', 'www.chenyang2020.com'), ('DNS', '*.chenyang2022.com')), 'version': 3}[{'issuer': ((('commonName', 'www.modelCA.com'),), (('organizationName', 'Model CA LTD.'),), (('countryName', 'US'),), (('stateOrProvinceName', 'New York'),), (('localityName', 'Syracuse'),)), 'notAfter': 'Aug 8 16:58:30 2032 GMT', 'notBefore': 'Aug 11 16:58:30 2022 GMT', 'serialNumber': '21678FD8BB56C6287E92E511DB8AC615C25B11E0', 'subject': ((('commonName', 'www.modelCA.com'),), (('organizationName', 'Model CA LTD.'),), (('countryName', 'US'),), (('stateOrProvinceName', 'New York'),), (('localityName', 'Syracuse'),)), 'version': 3}]After TLS handshake. Press any key to continue ...[b'\nHTTP/1.1 200 OK', b'Content-Type: text/html', b'', b'\nThis is Bank32.com!
\n']可以看出，所有域名都成功了。
Task 3: A Simple HTTPS Proxy
编写 proxy.py：
#!/usr/bin/env python3 import threading import ssl import socket cadir = "/etc/ssl/certs" def process_request(ssock_for_browser): hostname = "https://blog.csdn.net/qq_39678161/article/details/codeforces.com" # Make a connection to the real server sock_for_server = socket.create_connection((hostname, 443)) # Set up the TLS context context = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT) context.load_verify_locations(capath=cadir) context.verify_mode = ssl.CERT_REQUIRED context.check_hostname = True print("sock_for_server") ssock_for_server = context.wrap_socket(sock_for_server, server_hostname=hostname, do_handshake_on_connect=False) ssock_for_server.do_handshake() request = ssock_for_browser.recv(2048) if request: # Forward request to server ssock_for_server.sendall(request) # Get response from server, and forward it to browser response = ssock_for_server.recv(2048) while response: ssock_for_browser.sendall(response) # Forward to browser response = ssock_for_server.recv(2048) ssock_for_browser.shutdown(socket.SHUT_RDWR) ssock_for_browser.close() SERVER_CERT = "./cf.crt" SERVER_PRIVATE = "./cf.key" context_srv = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER) context_srv.load_cert_chain(SERVER_CERT, SERVER_PRIVATE) sock_listen = socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0) sock_listen.bind(("0.0.0.0", 443)) sock_listen.listen(5) while True: sock_for_browser, fromaddr = sock_listen.accept() print(fromaddr) ssock_for_browser = context_srv.wrap_socket(sock_for_browser, server_side=True) x = threading.Thread(target=process_request, args=(ssock_for_browser,)) x.start() 然后和上一节生成 server.crt 和 server.key 一样，生成 cf.crt 和 cf.key：
$ openssl req -newkey rsa:2048 -config ./cf_openssl.cnf -batch -sha256 -keyout cf.key -out cf.csrGenerating a RSA private key...............................+++++................+++++writing new private key to 'cf.key'Enter PEM pass phrase:Verifying - Enter PEM pass phrase:-----$ openssl ca -md sha256 -days 3650 -config ./myopenssl.cnf -batch -in cf.csr -out cf.crt -cert ca.crt -keyfile ca.keyUsing configuration from ./myopenssl.cnfEnter pass phrase for ca.key:Check that the request matches the signatureSignature okCertificate Details: Serial Number: 8193 (0x2001) Validity Not Before: Aug 11 17:19:52 2022 GMT Not After : Aug 8 17:19:52 2032 GMT Subject: countryName = US stateOrProvinceName = New York organizationName = Model CA LTD. commonName = https://blog.csdn.net/qq_39678161/article/details/codeforces.com X509v3 extensions: X509v3 Basic Constraints: CA:FALSE Netscape Comment: OpenSSL Generated Certificate X509v3 Subject Key Identifier: 27:DA:67:05:10:E9:FC:1A:46:C6:68:B4:D3:F3:AE:4E:1E:BE:EC:65 X509v3 Authority Key Identifier: keyid:28:63:81:40:6C:07:25:0D:B7:CC:16:F4:57:FF:94:08:1B:D0:C1:19 X509v3 Subject Alternative Name: DNS:https://blog.csdn.net/qq_39678161/article/details/codeforces.com, DNS:https://blog.csdn.net/qq_39678161/article/details/codeforces.com/*Certificate is to be certified until Aug 8 17:19:52 2032 GMT (3650 days)Write out database with 1 new entriesData Base Updated在 /etc/hosts 中添加：
10.9.0.143 https://blog.csdn.net/qq_39678161/article/details/codeforces.com修改 /etc/resolv.cnf 的 nameserver 为 8.8.8.8。
然后启动：
$ proxy.py访问 https://blog.csdn.net/qq_39678161/article/details/codeforces.com 可以看到：
$ proxy.pyEnter PEM pass phrase:('10.9.0.1', 52072)sock_for_server('10.9.0.1', 52080)sock_for_server('10.9.0.1', 52084)('10.9.0.1', 52086)('10.9.0.1', 52092)('10.9.0.1', 52094)sock_for_serversock_for_serversock_for_serversock_for_server表明成功添加了 proxy。
接下来我们进行登录操作并抓包：
我们使用 wireshark 连接 proxy，并抓取到相关报文：
报文具体的内容涉及个人隐私不放图了。经过简单过滤查找，我们发现 codeforces 的用户名和密码都是明文传输给服务器的，连哈希都没有做。
实验总结
本实验的遇到困难的地方在 task 2.c，要求证书与 CA 的 C、ST 等完全相同才能正常工作，否则会报错。经过查阅发现，这是签发策略导致的。策略通常有三种
- 匹配：要求申请填写的信息跟CA设置信息必须一致
- 支持：必须填写这项申请信息
- 可选：可有可无
而在本实验中使用的是匹配，所以必须和 CA 一模一样。
来源地址：https://blog.csdn.net/qq_39678161/article/details/126562335
