如何计算 OpenID Connect 服务器的指纹？

Question

在创建 OpenID Connect 提供程序（例如 AWS）时，我需要为连接器指定一个 thumbprint。它是什么，我如何获得它？

例如来自How can I connect GitHub actions with AWS deployments without using a secret key?

resource "aws_iam_openid_connect_provider" "github" {
  url = "https://token.actions.githubusercontent.com"
  client_id_list = [
    "githubactions",
  ]
  thumbprint_list = [
    "6938fd4d98bab03faadb97b34396831e3780aea1",
  ]
}

Answer 1

Open ID 连接器的指纹是主机公共证书的 SHA1 哈希。计算它需要获取服务的证书，然后使用openssl之类的工具计算hash。

考虑为 GitHub 操作 https://token.actions.githubusercontent.com 的 GitHub OpenID 连接器创建指纹（例如，因为您有兴趣将 GitHub 操作与 AWS 连接起来）。

您可以运行以下脚本来计算指纹：

% HOST=$(curl https://vstoken.actions.githubusercontent.com/.well-known/openid-configuration \
| jq -r '.jwks_uri | split("/")[2]')
% echo | openssl s_client -servername $HOST -showcerts -connect $HOST:443 2> /dev/null \
| sed -n -e '/BEGIN/h' -e '/BEGIN/,/END/H' -e '$x' -e '$p' | tail +2 \
| openssl x509 -fingerprint -noout \
| sed -e "s/.*=//" -e "s/://g" \
| tr "ABCDEF" "abcdef"
6938fd4d98bab03faadb97b34396831e3780aea1

这一切意味着什么？

OpenID 配置“众所周知的服务”，位于https://.../.well-known/openid-configuration，提供了已知服务的列表，包括.jwks_uri，如下所示：

{
  "issuer": "https://token.actions.githubusercontent.com",
  "jwks_uri": "https://token.actions.githubusercontent.com/.well-known/jwks",
  "subject_types_supported": [
    "public",
    "pairwise"
  ],
  "response_types_supported": [
    "id_token"
  ],
  "claims_supported": [
    "sub",
    "aud",
    "exp",
    "iat",
    "iss",
    "jti",
    "nbf",
    "ref",
    "repository",
    "repository_owner",
    "run_id",
    "run_number",
    "run_attempt",
    "actor",
    "workflow",
    "head_ref",
    "base_ref",
    "event_name",
    "ref_type",
    "environment",
    "job_workflow_ref"
  ],
  "id_token_signing_alg_values_supported": [
    "RS256"
  ],
  "scopes_supported": [
    "openid"
  ]
}

在这种情况下，它告诉客户端 Json Web 密钥服务 URI 要连接的主机位于 https://token.actions.githubusercontent.com/.well-known/jwks，但我们唯一需要的（对于 SSL 证书）是主机名 token.actions.githubusercontent.com .我们可以使用 JQ 将其通过管道传递给 split("/") 函数并获取 [2] 元素，在本例中它只是主机名。

在本例中，主机名与我们最初查询的主机名相同，但也可能不同。

从主机获取证书可以通过 OpenSSL 完成；我们使用openssl s_client -servername $HOST -showcerts -connect $HOST:443 与主机建立 TLS 连接并转储其证书。由于我们实际上不需要发送任何数据，因此我们通过管道输出echo 来启动会话通信。

这将导致输出如下所示：

CONNECTED(00000005)
---
Certificate chain
 0 s:/C=US/ST=California/L=San Francisco/O=GitHub, Inc./CN=*.actions.githubusercontent.com
   i:/C=US/O=DigiCert Inc/CN=DigiCert TLS RSA SHA256 2020 CA1
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
 1 s:/C=US/O=DigiCert Inc/CN=DigiCert TLS RSA SHA256 2020 CA1
   i:/C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert Global Root CA
-----BEGIN CERTIFICATE-----
MIIE6jCCA9KgAwIBAgIQCjUI1VwpKwF9+K1lwA/35DANBgkqhkiG9w0BAQsFADBh
MQswCQYDVQQGEwJVUzEVMBMGA1UEChMMRGlnaUNlcnQgSW5jMRkwFwYDVQQLExB3
d3cuZGlnaWNlcnQuY29tMSAwHgYDVQQDExdEaWdpQ2VydCBHbG9iYWwgUm9vdCBD
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Afr5yjK7tI4nhyfFK3TUqNaX3sNk+crOU6JWvHgXjkkDKa77SU+kFbnO8lwZV21r
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HR8EdDByMDegNaAzhjFodHRwOi8vY3JsMy5kaWdpY2VydC5jb20vRGlnaUNlcnRH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-----END CERTIFICATE-----
---
Server certificate
subject=/C=US/ST=California/L=San Francisco/O=GitHub, Inc./CN=*.actions.githubusercontent.com
issuer=/C=US/O=DigiCert Inc/CN=DigiCert TLS RSA SHA256 2020 CA1
---
No client certificate CA names sent
Server Temp Key: ECDH, P-384, 384 bits
---
SSL handshake has read 3571 bytes and written 398 bytes
---
New, TLSv1/SSLv3, Cipher is ECDHE-RSA-AES256-GCM-SHA384
Server public key is 2048 bit
Secure Renegotiation IS supported
Compression: NONE
Expansion: NONE
No ALPN negotiated
SSL-Session:
    Protocol  : TLSv1.2
    Cipher    : ECDHE-RSA-AES256-GCM-SHA384
    Session-ID: 223C0000364B663D9E1AD1A1287F2F351C1E6D66075F206C8802B43EC6110B7A
    Session-ID-ctx: 
    Master-Key: BBA59654810DE8EF29C2CEBB9CD1D4B886D2FF89359F24A664B31B7F71E7F1CFE719734548216CFC626EC39498EC4BE9
    Start Time: 1642416883
    Timeout   : 7200 (sec)
    Verify return code: 0 (ok)
---

还有一些额外的消息从这里打印到stderr，我们不需要，所以使用2> /dev/null 将其重定向到null。

这里我们真正需要的内容只是BEGIN和END部分之间的内容；具体来说，最后一个。如果您安装了tac，一个简单的方法是简单地向后转储它，打印出 END 和 BEGIN 证书之间的内容，然后停止；然后再次使用tac 反转它。

由于tac 在 macOS 上不存在，因此可以使用本机 sed 来完成这项工作：

• sed -n -- 运行 sed，但默认不打印任何输出
  • -e '/BEGIN/h' -- 看到 BEGIN 时，将 sed 保持缓冲区 设置为该行
  • -e '/BEGIN/,/END/H' -- 对于 BEGIN 和 END 之间的所有行，将它们附加到保持缓冲区（h 设置值，H 附加它，但我们最终在这里有两个 BEGINs）
  • -e '$x' -e '$p' -- 当你到达文件末尾时 ($) 将保持缓冲区换成输出缓冲区 (x) 然后打印出来 (p)
• tail +2 -- 从第 2 行开始打印，以避免上面重复的 BEGIN。
• openssl x509 -fingerprint -noout -- 将输出通过管道传输到 openssl，这将给出SHA1 Fingerprint= 69:38:FD:4D:98:BA:B0:3F:AA:DB:97:B3:43:96:83:1E:37:80:AE:A1 形式的指纹结果
• sed -e "s/.*=//" -e "s/://g" -- 删除直到并包括 = 符号的所有内容，然后从输出中删除所有冒号 (:)
• tr "ABCDEF" "abcdef" -- 将A 替换为a，将B 替换为b 等。（技术上不需要，但看起来不那么喧哗。

这个的最终结果，6938fd4d98bab03faadb97b34396831e3780aea1，就是在配置你的 OpenID 客户端时可以使用的指纹，比如How can I connect GitHub actions with AWS deployments without using a secret key?

注意GitHub（无意中）updated their thumbprint recently，所以结果从a031c46782e6e6c662c2c87c76da9aa62ccabd8e变了 给6938fd4d98bab03faadb97b34396831e3780aea1