1 files changed, 88 insertions, 0 deletions
diff --git a/libgo/go/crypto/tls/ca_set.go b/libgo/go/crypto/tls/ca_set.go
new file mode 100644
index 00000000000..fe2a540f4db
--- /dev/null
+++ b/libgo/go/crypto/tls/ca_set.go
@@ -0,0 +1,88 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package tls
+
+import (
+	"crypto/x509"
+	"encoding/pem"
+	"strings"
+)
+
+// A CASet is a set of certificates.
+type CASet struct {
+	bySubjectKeyId map[string][]*x509.Certificate
+	byName         map[string][]*x509.Certificate
+}
+
+func NewCASet() *CASet {
+	return &CASet{
+		make(map[string][]*x509.Certificate),
+		make(map[string][]*x509.Certificate),
+	}
+}
+
+func nameToKey(name *x509.Name) string {
+	return strings.Join(name.Country, ",") + "/" + strings.Join(name.Organization, ",") + "/" + strings.Join(name.OrganizationalUnit, ",") + "/" + name.CommonName
+}
+
+// FindVerifiedParent attempts to find the certificate in s which has signed
+// the given certificate. If no such certificate can be found or the signature
+// doesn't match, it returns nil.
+func (s *CASet) FindVerifiedParent(cert *x509.Certificate) (parent *x509.Certificate) {
+	var candidates []*x509.Certificate
+
+	if len(cert.AuthorityKeyId) > 0 {
+		candidates = s.bySubjectKeyId[string(cert.AuthorityKeyId)]
+	}
+	if len(candidates) == 0 {
+		candidates = s.byName[nameToKey(&cert.Issuer)]
+	}
+
+	for _, c := range candidates {
+		if cert.CheckSignatureFrom(c) == nil {
+			return c
+		}
+	}
+
+	return nil
+}
+
+// AddCert adds a certificate to the set
+func (s *CASet) AddCert(cert *x509.Certificate) {
+	if len(cert.SubjectKeyId) > 0 {
+		keyId := string(cert.SubjectKeyId)
+		s.bySubjectKeyId[keyId] = append(s.bySubjectKeyId[keyId], cert)
+	}
+	name := nameToKey(&cert.Subject)
+	s.byName[name] = append(s.byName[name], cert)
+}
+
+// SetFromPEM attempts to parse a series of PEM encoded root certificates. It
+// appends any certificates found to s and returns true if any certificates
+// were successfully parsed. On many Linux systems, /etc/ssl/cert.pem will
+// contains the system wide set of root CAs in a format suitable for this
+// function.
+func (s *CASet) SetFromPEM(pemCerts []byte) (ok bool) {
+	for len(pemCerts) > 0 {
+		var block *pem.Block
+		block, pemCerts = pem.Decode(pemCerts)
+		if block == nil {
+			break
+		}
+		if block.Type != "CERTIFICATE" || len(block.Headers) != 0 {
+			continue
+		}
+
+		cert, err := x509.ParseCertificate(block.Bytes)
+		if err != nil {
+			continue
+		}
+
+		s.AddCert(cert)
+		ok = true
+	}
+
+	return
+}