Update vendor lrstanley/girc

vendor/github.com/lrstanley/girc/cap_sasl.go

@@ -0,0 +1,137 @@
+// Copyright (c) Liam Stanley <me@liamstanley.io>. All rights reserved. Use
+// of this source code is governed by the MIT license that can be found in
+// the LICENSE file.
+
+package girc
+
+import (
+	"encoding/base64"
+	"fmt"
+)
+
+// SASLMech is an representation of what a SASL mechanism should support.
+// See SASLExternal and SASLPlain for implementations of this.
+type SASLMech interface {
+	// Method returns the uppercase version of the SASL mechanism name.
+	Method() string
+	// Encode returns the response that the SASL mechanism wants to use. If
+	// the returned string is empty (e.g. the mechanism gives up), the handler
+	// will attempt to panic, as expectation is that if SASL authentication
+	// fails, the client will disconnect.
+	Encode(params []string) (output string)
+}
+
+// SASLExternal implements the "EXTERNAL" SASL type.
+type SASLExternal struct {
+	// Identity is an optional field which allows the client to specify
+	// pre-authentication identification. This means that EXTERNAL will
+	// supply this in the initial response. This usually isn't needed (e.g.
+	// CertFP).
+	Identity string `json:"identity"`
+}
+
+// Method identifies what type of SASL this implements.
+func (sasl *SASLExternal) Method() string {
+	return "EXTERNAL"
+}
+
+// Encode for external SALS authentication should really only return a "+",
+// unless the user has specified pre-authentication or identification data.
+// See https://tools.ietf.org/html/rfc4422#appendix-A for more info.
+func (sasl *SASLExternal) Encode(params []string) string {
+	if len(params) != 1 || params[0] != "+" {
+		return ""
+	}
+
+	if sasl.Identity != "" {
+		return sasl.Identity
+	}
+
+	return "+"
+}
+
+// SASLPlain contains the user and password needed for PLAIN SASL authentication.
+type SASLPlain struct {
+	User string `json:"user"` // User is the username for SASL.
+	Pass string `json:"pass"` // Pass is the password for SASL.
+}
+
+// Method identifies what type of SASL this implements.
+func (sasl *SASLPlain) Method() string {
+	return "PLAIN"
+}
+
+// Encode encodes the plain user+password into a SASL PLAIN implementation.
+// See https://tools.ietf.org/rfc/rfc4422.txt for more info.
+func (sasl *SASLPlain) Encode(params []string) string {
+	if len(params) != 1 || params[0] != "+" {
+		return ""
+	}
+
+	in := []byte(sasl.User)
+
+	in = append(in, 0x0)
+	in = append(in, []byte(sasl.User)...)
+	in = append(in, 0x0)
+	in = append(in, []byte(sasl.Pass)...)
+
+	return base64.StdEncoding.EncodeToString(in)
+}
+
+const saslChunkSize = 400
+
+func handleSASL(c *Client, e Event) {
+	if e.Command == RPL_SASLSUCCESS || e.Command == ERR_SASLALREADY {
+		// Let the server know that we're done.
+		c.write(&Event{Command: CAP, Params: []string{CAP_END}})
+		return
+	}
+
+	// Assume they want us to handle sending auth.
+	auth := c.Config.SASL.Encode(e.Params)
+
+	if auth == "" {
+		// Assume the SASL authentication method doesn't want to respond for
+		// some reason. The SASL spec and IRCv3 spec do not define a clear
+		// way to abort a SASL exchange, other than to disconnect, or proceed
+		// with CAP END.
+		c.rx <- &Event{Command: ERROR, Trailing: fmt.Sprintf(
+			"closing connection: SASL %s failed: %s",
+			c.Config.SASL.Method(), e.Trailing,
+		)}
+		return
+	}
+
+	// Send in "saslChunkSize"-length byte chunks. If the last chuck is
+	// exactly "saslChunkSize" bytes, send a "AUTHENTICATE +" 0-byte
+	// acknowledgement response to let the server know that we're done.
+	for {
+		if len(auth) > saslChunkSize {
+			c.write(&Event{Command: AUTHENTICATE, Params: []string{auth[0 : saslChunkSize-1]}, Sensitive: true})
+			auth = auth[saslChunkSize:]
+			continue
+		}
+
+		if len(auth) <= saslChunkSize {
+			c.write(&Event{Command: AUTHENTICATE, Params: []string{auth}, Sensitive: true})
+
+			if len(auth) == 400 {
+				c.write(&Event{Command: AUTHENTICATE, Params: []string{"+"}})
+			}
+			break
+		}
+	}
+	return
+}
+
+func handleSASLError(c *Client, e Event) {
+	if c.Config.SASL == nil {
+		c.write(&Event{Command: CAP, Params: []string{CAP_END}})
+		return
+	}
+
+	// Authentication failed. The SASL spec and IRCv3 spec do not define a
+	// clear way to abort a SASL exchange, other than to disconnect, or
+	// proceed with CAP END.
+	c.rx <- &Event{Command: ERROR, Trailing: "closing connection: " + e.Trailing}
+}