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authorRuss Cox <rsc@golang.org>2014-09-08 00:08:51 -0400
committerRuss Cox <rsc@golang.org>2014-09-08 00:08:51 -0400
commit8528da672cc093d4dd06732819abc1f7b6b5a46e (patch)
tree334be80d4a4c85b77db6f6fdb67cbf0528cba5f5 /src/net/smtp/auth.go
parent73bcb69f272cbf34ddcc9daa56427a8683b5a95d (diff)
downloadgo-8528da672cc093d4dd06732819abc1f7b6b5a46e.tar.gz
build: move package sources from src/pkg to src
Preparation was in CL 134570043. This CL contains only the effect of 'hg mv src/pkg/* src'. For more about the move, see golang.org/s/go14nopkg.
Diffstat (limited to 'src/net/smtp/auth.go')
-rw-r--r--src/net/smtp/auth.go107
1 files changed, 107 insertions, 0 deletions
diff --git a/src/net/smtp/auth.go b/src/net/smtp/auth.go
new file mode 100644
index 000000000..3f1339ebc
--- /dev/null
+++ b/src/net/smtp/auth.go
@@ -0,0 +1,107 @@
+// Copyright 2010 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 smtp
+
+import (
+ "crypto/hmac"
+ "crypto/md5"
+ "errors"
+ "fmt"
+)
+
+// Auth is implemented by an SMTP authentication mechanism.
+type Auth interface {
+ // Start begins an authentication with a server.
+ // It returns the name of the authentication protocol
+ // and optionally data to include in the initial AUTH message
+ // sent to the server. It can return proto == "" to indicate
+ // that the authentication should be skipped.
+ // If it returns a non-nil error, the SMTP client aborts
+ // the authentication attempt and closes the connection.
+ Start(server *ServerInfo) (proto string, toServer []byte, err error)
+
+ // Next continues the authentication. The server has just sent
+ // the fromServer data. If more is true, the server expects a
+ // response, which Next should return as toServer; otherwise
+ // Next should return toServer == nil.
+ // If Next returns a non-nil error, the SMTP client aborts
+ // the authentication attempt and closes the connection.
+ Next(fromServer []byte, more bool) (toServer []byte, err error)
+}
+
+// ServerInfo records information about an SMTP server.
+type ServerInfo struct {
+ Name string // SMTP server name
+ TLS bool // using TLS, with valid certificate for Name
+ Auth []string // advertised authentication mechanisms
+}
+
+type plainAuth struct {
+ identity, username, password string
+ host string
+}
+
+// PlainAuth returns an Auth that implements the PLAIN authentication
+// mechanism as defined in RFC 4616.
+// The returned Auth uses the given username and password to authenticate
+// on TLS connections to host and act as identity. Usually identity will be
+// left blank to act as username.
+func PlainAuth(identity, username, password, host string) Auth {
+ return &plainAuth{identity, username, password, host}
+}
+
+func (a *plainAuth) Start(server *ServerInfo) (string, []byte, error) {
+ if !server.TLS {
+ advertised := false
+ for _, mechanism := range server.Auth {
+ if mechanism == "PLAIN" {
+ advertised = true
+ break
+ }
+ }
+ if !advertised {
+ return "", nil, errors.New("unencrypted connection")
+ }
+ }
+ if server.Name != a.host {
+ return "", nil, errors.New("wrong host name")
+ }
+ resp := []byte(a.identity + "\x00" + a.username + "\x00" + a.password)
+ return "PLAIN", resp, nil
+}
+
+func (a *plainAuth) Next(fromServer []byte, more bool) ([]byte, error) {
+ if more {
+ // We've already sent everything.
+ return nil, errors.New("unexpected server challenge")
+ }
+ return nil, nil
+}
+
+type cramMD5Auth struct {
+ username, secret string
+}
+
+// CRAMMD5Auth returns an Auth that implements the CRAM-MD5 authentication
+// mechanism as defined in RFC 2195.
+// The returned Auth uses the given username and secret to authenticate
+// to the server using the challenge-response mechanism.
+func CRAMMD5Auth(username, secret string) Auth {
+ return &cramMD5Auth{username, secret}
+}
+
+func (a *cramMD5Auth) Start(server *ServerInfo) (string, []byte, error) {
+ return "CRAM-MD5", nil, nil
+}
+
+func (a *cramMD5Auth) Next(fromServer []byte, more bool) ([]byte, error) {
+ if more {
+ d := hmac.New(md5.New, []byte(a.secret))
+ d.Write(fromServer)
+ s := make([]byte, 0, d.Size())
+ return []byte(fmt.Sprintf("%s %x", a.username, d.Sum(s))), nil
+ }
+ return nil, nil
+}