由于 x509 证书依赖于旧的 Common Name 字段，无法使用 Golang 连接到服务器

Question

我正在尝试连接 mongodb 服务器，要连接我必须提供 CA 证书文件以及 tls 证书文件。

当我使用以下命令时没有问题

$ mongo --host customhost:port DB --authenticationDatabase=DB -u ACCOUNT -p PWD --tls --tlsCAFile /etc/ca-files/new-mongo.ca.crt --tlsCertificateKeyFile /etc/ca-files/new-mongo-client.pem

但是当我尝试与 mongo 连接时（也仅使用 tls 客户端进行测试）我遇到以下错误：

failed to connect: x509: certificate relies on legacy Common Name field, use SANs or temporarily enable Common Name matching with GODEBUG=x509ignoreCN=0

如果我使用 env 变量一切正常，但我想知道如何在不使用它的情况下修复它。

const CONFIG_DB_CA = "/etc/ca-files/new-mongo.ca.crt"

func main() {
    cer, err := tls.LoadX509KeyPair("mongo-server.crt", "mongo-server.key")
    if err != nil {
        log.Println(err)
        return
    }

    roots := x509.NewCertPool()
    ca, err := ioutil.ReadFile(CONFIG_DB_CA)
    if err != nil {
        fmt.Printf("Failed to read or open CA File: %s.\n", CONFIG_DB_CA)
        return
    }
    roots.AppendCertsFromPEM(ca)

    tlsConfig := &tls.Config{
        Certificates: []tls.Certificate{cer},
        RootCAs:      roots,
    }

    conn, err := tls.Dial("tcp", "customhost:port", tlsConfig)
    if err != nil {
        fmt.Printf("failed to connect: %v.\n", err)
        return
    }

    err = conn.VerifyHostname("customhost")
    if err != nil {
        panic("Hostname doesn't match with certificate: " + err.Error())
    }
    for i, cert := range conn.ConnectionState().PeerCertificates {
        prefix := fmt.Sprintf("CERT%d::", i+1)
        fmt.Printf("%sIssuer: %s\n", prefix, cert.Issuer)
        fmt.Printf("%sExpiry: %v\n", prefix, cert.NotAfter.Format(time.RFC850))
        fmt.Printf("%sDNSNames: %v\n\n", prefix, cert.DNSNames)
    }
    
    fmt.Printf("Success!")
}

证书：

$ openssl x509 -in /etc/ca-files/new-mongo.ca.crt -text -noout
Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number:
            ....
        Signature Algorithm: sha256WithRSAEncryption
        Issuer: C = FR, ST = IDF, L = Paris, O = COMP, OU = IT, CN = newmongo
        Validity
            Not Before: Jun 30 13:02:12 2021 GMT
            Not After : Jun 30 13:02:12 2023 GMT
        Subject: C = FR, ST = IDF, L = Paris, O = COMP, OU = IT, CN = newmongo

...

        X509v3 extensions:
            X509v3 Subject Key Identifier: 
                ...
            X509v3 Authority Key Identifier: 
                ....

            X509v3 Basic Constraints: critical
                CA:TRUE

$ openssl x509 -in /etc/ca-files/newmongo-client.pem -text -noout 
Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number:
            ...
        Signature Algorithm: sha256WithRSAEncryption
        Issuer: C = FR, ST = IDF, L = Paris, O = COMP, OU = IT, CN = newmongo
        Validity
            Not Before: Jun 30 13:17:25 2021 GMT
            Not After : Jun 30 13:17:25 2023 GMT
        Subject: C = FR, ST = IDF, L = Paris, O = COMP, OU = IT, CN = newmongo-client
...
        X509v3 extensions:
            X509v3 Subject Alternative Name: 
                DNS:customhost:port, DNS:customhost, DNS:newmongo-client

我有点卡住了，不知道问题是出在我的 tls 代码配置和我加载证书的方式上，还是出在 SSL 证书配置错误但哪些证书看起来不错。我觉得加载的证书因任何原因被忽略

感谢您的帮助

Answer 1

您需要从源头上解决问题并生成带有 DNS SAN 字段的证书 - 然后 Go 运行时检查将消失。

这可以通过 openssl 实现，但由于它需要一个配置文件而变得棘手 - 因为 SAN 字段选项太宽泛而无法放入简单的命令行选项。

总的要点是，创建一个 CSR:

openssl req -new \
    -subj "${SUBJ_PREFIX}/CN=${DNS}/emailAddress=${EMAIL}" \
            -key "${KEY}" \
    -addext "subjectAltName = DNS:${DNS}" \
    -out "${CSR}"

然后用你的 root CA:

签署 CSR

openssl ca \
        -create_serial \
                -cert "${ROOT_CRT}" \
        -keyfile "${ROOT_KEY}" \
                -days "${CERT_LIFETIME}" \
                -in "${CSR}" \
        -batch \
        -config "${CA_CONF}" \
                -out "${CRT}"

上面引用的

CA_CONF 看起来像这样：

[ ca ]
default_ca      = my_ca

[ my_ca ]
dir             = ./db
database            = $dir/index.txt
serial              = $dir/serial
new_certs_dir   = $dir/tmp
x509_extensions = my_cert
name_opt            = ca_default
cert_opt            = ca_default
default_md          = default
policy              = policy_match
# 'copy_extensions' will copy over SAN ("X509v3 Subject Alternative Name") from CSR
copy_extensions = copy

[ my_cert ]
basicConstraints        = CA:FALSE
nsComment               = "generated by https://github.com/me/my-pki"
subjectKeyIdentifier    = hash
authorityKeyIdentifier  = keyid,issuer

[ policy_match ]
# ensure CSR fields match that of delivered Cert
countryName             = match
stateOrProvinceName     = match
organizationName        = match
organizationalUnitName  = optional
commonName              = supplied
emailAddress            = optional

检查生成的服务器证书：

openssl x509 -in server.crt -noout -text

然后应该有一个 SAN 部分，例如：

X509v3 Subject Alternative Name: 
    DNS:myserver.com

由于 x509 证书依赖于旧的 Common Name 字段，无法使用 Golang 连接到服务器

Failed to connect to a server with Golang due x509 certificate relies on legacy Common Name field

ssl

ca

go

mongodb

handshake