caddy/modules/caddytls/certselection.go
2020-03-15 21:18:00 -06:00

86 lines
2.7 KiB
Go

// Copyright 2015 Matthew Holt and The Caddy Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package caddytls
import (
"crypto/tls"
"crypto/x509"
"fmt"
"math/big"
"github.com/caddyserver/caddy/v2"
"github.com/caddyserver/certmagic"
)
func init() {
caddy.RegisterModule(CustomCertSelectionPolicy{})
}
// CustomCertSelectionPolicy represents a policy for selecting the certificate
// used to complete a handshake when there may be multiple options. All fields
// specified must match the candidate certificate for it to be chosen.
// This was needed to solve https://github.com/caddyserver/caddy/issues/2588.
type CustomCertSelectionPolicy struct {
SerialNumber *big.Int `json:"serial_number,omitempty"`
SubjectOrganization string `json:"subject_organization,omitempty"`
PublicKeyAlgorithm PublicKeyAlgorithm `json:"public_key_algorithm,omitempty"`
Tag string `json:"tag,omitempty"`
}
// CaddyModule returns the Caddy module information.
func (CustomCertSelectionPolicy) CaddyModule() caddy.ModuleInfo {
return caddy.ModuleInfo{
ID: "tls.certificate_selection.custom",
New: func() caddy.Module { return new(CustomCertSelectionPolicy) },
}
}
// SelectCertificate implements certmagic.CertificateSelector.
func (p CustomCertSelectionPolicy) SelectCertificate(_ *tls.ClientHelloInfo, choices []certmagic.Certificate) (certmagic.Certificate, error) {
for _, cert := range choices {
if p.SerialNumber != nil && cert.SerialNumber.Cmp(p.SerialNumber) != 0 {
continue
}
if p.PublicKeyAlgorithm != PublicKeyAlgorithm(x509.UnknownPublicKeyAlgorithm) &&
PublicKeyAlgorithm(cert.PublicKeyAlgorithm) != p.PublicKeyAlgorithm {
continue
}
if p.SubjectOrganization != "" {
var matchOrg bool
for _, org := range cert.Subject.Organization {
if p.SubjectOrganization == org {
matchOrg = true
break
}
}
if !matchOrg {
continue
}
}
if p.Tag != "" && !cert.HasTag(p.Tag) {
continue
}
return cert, nil
}
return certmagic.Certificate{}, fmt.Errorf("no certificates matched custom selection policy")
}
// Interface guard
var _ certmagic.CertificateSelector = (*CustomCertSelectionPolicy)(nil)