cloudflared-mirror/tlsconfig/tlsconfig.go

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// Package tlsconfig provides convenience functions for configuring TLS connections from the
// command line.
package tlsconfig
import (
"crypto/tls"
"crypto/x509"
"io/ioutil"
"github.com/pkg/errors"
)
// Config is the user provided parameters to create a tls.Config
type TLSParameters struct {
Cert string
Key string
GetCertificate *CertReloader
ClientCAs []string
RootCAs []string
ServerName string
CurvePreferences []tls.CurveID
MinVersion uint16 // min tls version. If zero, TLS1.0 is defined as minimum.
MaxVersion uint16 // max tls version. If zero, last TLS version is used defined as limit (currently TLS1.3)
}
// GetConfig returns a TLS configuration according to the Config set by the user.
func GetConfig(p *TLSParameters) (*tls.Config, error) {
tlsconfig := &tls.Config{}
if p.Cert != "" && p.Key != "" {
cert, err := tls.LoadX509KeyPair(p.Cert, p.Key)
if err != nil {
return nil, errors.Wrap(err, "Error parsing X509 key pair")
}
tlsconfig.Certificates = []tls.Certificate{cert}
// BuildNameToCertificate parses Certificates and builds NameToCertificate from common name
// and SAN fields of leaf certificates
tlsconfig.BuildNameToCertificate()
}
if p.GetCertificate != nil {
// GetCertificate is called when client supplies SNI info or Certificates is empty.
// Order of retrieving certificate is GetCertificate, NameToCertificate and lastly first element of Certificates
tlsconfig.GetCertificate = p.GetCertificate.Cert
}
if len(p.ClientCAs) > 0 {
// set of root certificate authorities that servers use if required to verify a client certificate
// by the policy in ClientAuth
clientCAs, err := LoadCert(p.ClientCAs)
if err != nil {
return nil, errors.Wrap(err, "Error loading client CAs")
}
tlsconfig.ClientCAs = clientCAs
// server's policy for TLS Client Authentication. Default is no client cert
tlsconfig.ClientAuth = tls.RequireAndVerifyClientCert
}
if len(p.RootCAs) > 0 {
rootCAs, err := LoadCert(p.RootCAs)
if err != nil {
return nil, errors.Wrap(err, "Error loading root CAs")
}
tlsconfig.RootCAs = rootCAs
}
if p.ServerName != "" {
tlsconfig.ServerName = p.ServerName
}
if len(p.CurvePreferences) > 0 {
tlsconfig.CurvePreferences = p.CurvePreferences
} else {
// Cloudflare optimize CurveP256
tlsconfig.CurvePreferences = []tls.CurveID{tls.CurveP256}
}
tlsconfig.MinVersion = p.MinVersion
tlsconfig.MaxVersion = p.MaxVersion
return tlsconfig, nil
}
// LoadCert creates a CertPool containing all certificates in a PEM-format file.
func LoadCert(certPaths []string) (*x509.CertPool, error) {
ca := x509.NewCertPool()
for _, certPath := range certPaths {
caCert, err := ioutil.ReadFile(certPath)
if err != nil {
return nil, errors.Wrapf(err, "Error reading certificate %s", certPath)
}
if !ca.AppendCertsFromPEM(caCert) {
return nil, errors.Wrapf(err, "Error parsing certificate %s", certPath)
}
}
return ca, nil
}