ruby - 在 ruby​​ 中使用 OpenSSL 解密 aes-128-gcm tls 包时的一个非常奇怪的现象

Question

我正在使用自己的 ssl/tls 库进行学习。这些天，当我将加密消息播种到服务器时，我会收到“bad mac”警报。今天我用这个问题的记录来调试我的代码。

这就是奇怪的事情发生的地方。我使用他的 server_random、client_random 和 master-secret 来生成 client_write_key 和 client_write_iv。然后我得到与他相同的输出。但是，当我使用 client_wrtie_key 和 client_write_iv 解密“GET / HTTP/1.0\n”消息时，我得到以下输出：

Q▒W▒            ▒7▒3▒▒▒

这与正确的消息是如此不同！我的整个调试输出是

C:/Users/ayanamists/.babun/cygwin/home/ayanamists/my_ssl_in_ruby/encrypt_handler/aes_gcm_handler.rb:87:in `final': OpenSSL::Cipher::CipherError
        from C:/Users/ayanamists/.babun/cygwin/home/ayanamists/my_ssl_in_ruby/encrypt_handler/aes_gcm_handler.rb:87:in `recv_decrypt'
        from decrypt.rb:72:in `<main>'
client write key is
 4b 11 9d fb fc 93 0a be 13 00 30 bd 53 c3 bf 78
nonce is
 20 29 ca e2 c9 1d e0 05 e2 ae 50 a8
what to be decrypt:
 a5 7a be e5 5c 18 36 67 b1 36 34 3f ee f4 a3 87 cb 7c f8 30 30
the tag is
 a4 7e 23 0a f2 68 37 8c 4f 33 c8 b5 ba b3 d2 6d
the additional data is
 00 00 00 00 00 00 00 01 17 03 03 00 00 15
decrypter is
 OpenSSL::Cipher::AES
Q▒W▒            ▒7▒3▒▒▒
output is
 bd 8c e8 87 b7 ab c6 f7 eb 31 fd cb 65 4c d4 a9 16 ae 1b ca da
the correct is
 47 45 54 20 2f 20 48 54 54 50 2f 31 2e 30 0a

你可以看到我的key和nonce和他的key和nonce没有区别，但是为什么结果是错误的呢？代码是：

require_relative 'encrypt_message_handler'
require 'pp'

class AES_CGM_Handler
    include EncryptMessageHandler
    attr_accessor :send_cipher, :recv_cipher, :send_implicit, :recv_implicit,
    :send_seq_num, :recv_seq_num
    def initialize(server_random, client_random, certificate = '', length = 0, 
        usage = 'client', version_major = 0x03, version_minor = 0x03)
        if block_given?
            @master = yield
            @version = [0x03, 0x03]
        else
            super(server_random, client_random, certificate)
        end
        # the nonce of AES_GCM is defined by:
        # +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        # +  0  1  2  3 | 0  1  2  3  4  5  6  7    +
        # +     salt    |     nonce_explicit        +
        # +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        # salt is server_write_iv or client_write_iv, so you need 4 * 2
        # and length need to /8(bit->byte) and * 2(both server and client), so it's length/4
        key_block = (length/4 + 4 * 2).tls_prf(@master, "key expansion", server_random + client_random)
        arr = key_block.unpack "a#{length/8}a#{length/8}a4a4"
        client_write_key = arr[0]
        server_write_key = arr[1]
        client_write_iv = arr[2]
        server_write_iv = arr[3]

        @send_cipher = OpenSSL::Cipher::AES.new(length, :GCM).encrypt
        @recv_cipher = OpenSSL::Cipher::AES.new(length, :GCM).decrypt
        if usage == 'client'
            @send_cipher.key = client_write_key
            @send_implicit = client_write_iv
            @recv_cipher.key = server_write_key
            @recv_implicit = server_write_iv
            puts "server write key is #{server_write_key.to_hex}"
        elsif usage == 'server'
            @send_cipher.key = server_write_key
            @send_implicit = server_write_iv
            @recv_cipher.key = client_write_key
            @recv_implicit = client_write_iv
            puts "client write key is\n #{client_write_key.to_hex}"
        else
            raise "AES_GCM_HANDLER: BAD_ARGUMENT"
        end

        @send_seq_num = 0
        @recv_seq_num = 0
    end

    def send_encrypt(type = 22, seqence = '')
        nonce_explicit = OpenSSL::Random.random_bytes(8)
        nonce = @send_implicit + nonce_explicit
        @send_cipher.iv = nonce
        length = seqence.length
        #the handle of seq_num may be wrong
        @send_cipher.auth_data = [0, @send_seq_num,
            type, @version[0], @version[1], 0 ,length].pack("NNCCCCn")
        encrypt = @send_cipher.update(seqence) + @send_cipher.final
        encrypt = encrypt + @send_cipher.auth_tag
        return encrypt
    end

    def recv_decrypt(type = 22, sequence = '', seq_num = 0)
        if seq_num != 0
            @recv_seq_num = seq_num
        end
        template = 'a8a*'
        arr = sequence.unpack(template)
        nonce_explicit = arr[0]
        length = sequence.length - 8 - 16
        sequence = arr[1]
        encrypted = sequence[0, sequence.length - 16]
        @recv_cipher.auth_tag = sequence[sequence.length - 16, sequence.length]
        @recv_cipher.iv = @recv_implicit + nonce_explicit
        puts "nonce is\n #{(@recv_implicit + nonce_explicit).to_hex}"
        puts "what to be decrypt: \n #{encrypted.to_hex}" 
        puts "the tag is \n #{sequence[sequence.length - 16, sequence.length].to_hex}"
        @recv_cipher.auth_data =
            [0, @recv_seq_num, type ,@version[0], @version[1], 0 ,length].pack("NNCCCCn")
        puts "the additional data is\n #{([0, @recv_seq_num, type ,@version[0], @version[1], 0 ,length].pack("NNCCCCn")).to_hex }"
        puts "decrypter is\n #{@recv_cipher.class}"
        puts @recv_cipher.update(encrypted)
        puts "output is\n #{@recv_cipher.update(encrypted).to_hex}"
        puts "the correct is\n #{"GET / HTTP/1.0\n".to_hex}"
        decrypt = @recv_cipher.update(encrypted) + @recv_cipher.final
        return decrypt
    end
end

请帮我解决这个问题，我将不胜感激！

标签： rubyencryptionopensslcryptographytls1.2

Answer 1

我终于解决了这个问题！如果有人想使用此测试向量，请不要忘记将“789c”添加为 zlib compress