OpenSSL の -trace オプションを使って SSL/TLS のメッセージを観察する

openssl s_client コマンドの -trace オプションを使うと SSL/TLS のメッセージを人間に優しい形でみることができる。 どういうメッセージが見られるかは OpenSSL with trace などで試すことができる。

ただ、リファレンスにある通り、このオプションは enable-ssl-trace をつけてビルドをしないと利用できず、例えば apt で配布されているバイナリでは無効になっている。

なので、 Debian buster コンテナ上でのビルド方法をここにメモしておく。

$ docker run -it --rm buildpack-deps:buster bash
root# cd /usr/local/src
root# curl -O https://www.openssl.org/source/openssl-1.1.1d.tar.gz
root# tar zxf openssl-1.1.1d.tar.gz
root# cd openssl-1.1.1d
root# ./config enable-ssl-trace && make && make install && make clean && ldconfig

こんな感じ。

root# openssl s_client -trace -connect google.com:443 -cipher "DEFAULT:@SECLEVEL=2"
CONNECTED(00000003)
Sent Record
Header:
  Version = TLS 1.0 (0x301)
  Content Type = Handshake (22)
  Length = 301
    ClientHello, Length=297
      client_version=0x303 (TLS 1.2)
      Random:
        gmt_unix_time=0xBF8D65C0
        random_bytes (len=28): (snip)
      session_id (len=32): (snip)
      cipher_suites (len=62)
        {0x13, 0x02} TLS_AES_256_GCM_SHA384
        {0x13, 0x03} TLS_CHACHA20_POLY1305_SHA256
        {0x13, 0x01} TLS_AES_128_GCM_SHA256
        {0xC0, 0x2C} TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
        {0xC0, 0x30} TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
        {0x00, 0x9F} TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
        {0xCC, 0xA9} TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
        {0xCC, 0xA8} TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
        {0xCC, 0xAA} TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256
        {0xC0, 0x2B} TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
        {0xC0, 0x2F} TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
        {0x00, 0x9E} TLS_DHE_RSA_WITH_AES_128_GCM_SHA256
        {0xC0, 0x24} TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384
        {0xC0, 0x28} TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
        {0x00, 0x6B} TLS_DHE_RSA_WITH_AES_256_CBC_SHA256
        {0xC0, 0x23} TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256
        {0xC0, 0x27} TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
        {0x00, 0x67} TLS_DHE_RSA_WITH_AES_128_CBC_SHA256
        {0xC0, 0x0A} TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
        {0xC0, 0x14} TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
        {0x00, 0x39} TLS_DHE_RSA_WITH_AES_256_CBC_SHA
        {0xC0, 0x09} TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
        {0xC0, 0x13} TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
        {0x00, 0x33} TLS_DHE_RSA_WITH_AES_128_CBC_SHA
        {0x00, 0x9D} TLS_RSA_WITH_AES_256_GCM_SHA384
        {0x00, 0x9C} TLS_RSA_WITH_AES_128_GCM_SHA256
        {0x00, 0x3D} TLS_RSA_WITH_AES_256_CBC_SHA256
        {0x00, 0x3C} TLS_RSA_WITH_AES_128_CBC_SHA256
        {0x00, 0x35} TLS_RSA_WITH_AES_256_CBC_SHA
        {0x00, 0x2F} TLS_RSA_WITH_AES_128_CBC_SHA
        {0x00, 0xFF} TLS_EMPTY_RENEGOTIATION_INFO_SCSV
      compression_methods (len=1)
        No Compression (0x00)
      extensions, length = 162
        extension_type=server_name(0), length=15
          0000 - 00 0d 00 00 0a 67 6f 6f-67 6c 65 2e 63 6f 6d   .....google.com
        extension_type=ec_point_formats(11), length=4
          uncompressed (0)
          ansiX962_compressed_prime (1)
          ansiX962_compressed_char2 (2)
        extension_type=supported_groups(10), length=12
          ecdh_x25519 (29)
          secp256r1 (P-256) (23)
          ecdh_x448 (30)
          secp521r1 (P-521) (25)
          secp384r1 (P-384) (24)
        extension_type=session_ticket(35), length=0
        extension_type=encrypt_then_mac(22), length=0
        extension_type=extended_master_secret(23), length=0
        extension_type=signature_algorithms(13), length=42
          ecdsa_secp256r1_sha256 (0x0403)
          ecdsa_secp384r1_sha384 (0x0503)
          ecdsa_secp521r1_sha512 (0x0603)
          ed25519 (0x0807)
          ed448 (0x0808)
          rsa_pss_pss_sha256 (0x0809)
          rsa_pss_pss_sha384 (0x080a)
          rsa_pss_pss_sha512 (0x080b)
          rsa_pss_rsae_sha256 (0x0804)
          rsa_pss_rsae_sha384 (0x0805)
          rsa_pss_rsae_sha512 (0x0806)
          rsa_pkcs1_sha256 (0x0401)
          rsa_pkcs1_sha384 (0x0501)
          rsa_pkcs1_sha512 (0x0601)
          ecdsa_sha224 (0x0303)
          rsa_pkcs1_sha224 (0x0301)
          dsa_sha224 (0x0302)
          dsa_sha256 (0x0402)
          dsa_sha384 (0x0502)
          dsa_sha512 (0x0602)
        extension_type=supported_versions(43), length=9
          TLS 1.3 (772)
          TLS 1.2 (771)
          TLS 1.1 (770)
          TLS 1.0 (769)
        extension_type=psk_key_exchange_modes(45), length=2
          psk_dhe_ke (1)
        extension_type=key_share(51), length=38
            NamedGroup: ecdh_x25519 (29)
            key_exchange:  (len=32): (snip)

Received Record
Header:
  Version = TLS 1.2 (0x303)
  Content Type = Handshake (22)
  Length = 122
    ServerHello, Length=118
      server_version=0x303 (TLS 1.2)
      Random:
        gmt_unix_time=0x142E888C
        random_bytes (len=28): (snip)
      session_id (len=32): (snip)
      cipher_suite {0x13, 0x02} TLS_AES_256_GCM_SHA384
      compression_method: No Compression (0x00)
      extensions, length = 46
        extension_type=key_share(51), length=36
            NamedGroup: ecdh_x25519 (29)
            key_exchange:  (len=32): (snip)
        extension_type=supported_versions(43), length=2
            TLS 1.3 (772)
(snip)