improve sasl implementation
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parent
42d17746e8
commit
30b2e2f7f8
122
cap.go
122
cap.go
@ -177,15 +177,20 @@ func handleCAP(c *Client, e Event) {
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type SASLMech interface {
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// Method returns the uppercase version of the SASL mechanism name.
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Method() string
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// Encode returns the response that the SASL mechanism wants to use,
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// chunked out as necessary. if this returns nil, an "AUTHENTICATE +" will
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// be used to respond (essentially telling the server that it should handle
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// the rest.)
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Encode(chunkSize int) (chunks []string)
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// Encode returns the response that the SASL mechanism wants to use. If
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// the returned string is empty (e.g. the mechanism gives up), the handler
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// will attempt to panic, as expectation is that if SASL authentication
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// fails, the client will disconnect.
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Encode(params []string) (output string)
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}
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// SASLExternal implements the "EXTERNAL" SASL type.
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type SASLExternal struct {
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// Identity is an optional field which allows the client to specify
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// pre-authentication identification. This means that EXTERNAL will
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// supply this in the initial response. This usually isn't needed (e.g.
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// CertFP).
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Identity string
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}
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// Method identifies what type of SASL this implements.
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@ -193,10 +198,19 @@ func (sasl *SASLExternal) Method() string {
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return "EXTERNAL"
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}
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// Encode is not directly used by SASLExternal -- it currently only returns
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// nil.
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func (sasl *SASLExternal) Encode(chunkSize int) (chunks []string) {
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return nil
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// Encode for external SALS authentication should really only return a "+",
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// unless the user has specified pre-authentication or identification data.
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// See https://tools.ietf.org/html/rfc4422#appendix-A for more info.
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func (sasl *SASLExternal) Encode(params []string) string {
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if len(params) != 1 || params[0] != "+" {
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return ""
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}
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if sasl.Identity != "" {
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return sasl.Identity
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}
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return "+"
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}
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// SASLPlain contains the user and password needed for PLAIN SASL authentication.
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@ -210,8 +224,13 @@ func (sasl *SASLPlain) Method() string {
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return "PLAIN"
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}
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// Encode encodes the plain user+password into a standardized chunk size.
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func (sasl *SASLPlain) Encode(chunkSize int) (chunks []string) {
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// Encode encodes the plain user+password into a SASL PLAIN implementation.
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// See https://tools.ietf.org/rfc/rfc4422.txt for more info.
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func (sasl *SASLPlain) Encode(params []string) string {
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if len(params) != 1 || params[0] != "+" {
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return ""
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}
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in := []byte(sasl.User)
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in = append(in, 0x0)
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@ -219,24 +238,11 @@ func (sasl *SASLPlain) Encode(chunkSize int) (chunks []string) {
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in = append(in, 0x0)
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in = append(in, []byte(sasl.Pass)...)
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out := base64.StdEncoding.EncodeToString(in)
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for {
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if len(out) > chunkSize {
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chunks = append(chunks, out[0:chunkSize-1])
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out = out[chunkSize:]
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continue
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}
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if len(out) <= chunkSize {
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chunks = append(chunks, out)
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break
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}
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}
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return chunks
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return base64.StdEncoding.EncodeToString(in)
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}
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const saslChunkSize = 400
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func handleSASL(c *Client, e Event) {
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if e.Command == RPL_SASLSUCCESS || e.Command == ERR_SASLALREADY {
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// Let the server know that we're done.
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@ -244,39 +250,65 @@ func handleSASL(c *Client, e Event) {
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return
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}
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if len(e.Params) == 1 && e.Params[0] == "+" {
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// Assume they want us to handle sending auth.
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auth := c.Config.SASL.Encode(400)
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// Assume they want us to handle sending auth.
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auth := c.Config.SASL.Encode(e.Params)
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if auth == nil {
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// Assume the SASL authentication method doesn't need to encode
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// data and pass it to the server.
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c.write(&Event{Command: AUTHENTICATE, Params: []string{"+"}})
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return
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if auth == "" {
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// Assume the SASL authentication method doesn't want to respond
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// for some reason. Unfortunately, the SALS spec and IRCv3 spec do
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// not define a clear way to abort a SASL exchange, other than
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// disconnecting or sending a "CAP END".
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//
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// One can avoid disconnecting by handling this error using a
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// Config.RecoverFunc.
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panic(ErrAuthSASL{Method: c.Config.SASL.Method(), Cmd: e.Command, Text: e.Trailing})
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}
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// Send in "saslChunkSize"-length byte chunks. If the last chuck is
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// exactly "saslChunkSize" bytes, send a "AUTHENTICATE +" 0-byte
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// acknowledgement response to let the server know that we're done.
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for {
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if len(auth) > saslChunkSize {
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c.write(&Event{Command: AUTHENTICATE, Params: []string{auth[0 : saslChunkSize-1]}, Sensitive: true})
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auth = auth[saslChunkSize:]
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continue
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}
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// Send in 400 byte chunks. If the last chuck is exactly 400 bytes,
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// send a "AUTHENTICATE +" 0-byte response to let the server know
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// that we're done.
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for i := 0; i < len(auth); i++ {
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c.write(&Event{Command: AUTHENTICATE, Params: []string{auth[i]}, Sensitive: true})
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if len(auth) <= saslChunkSize {
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c.write(&Event{Command: AUTHENTICATE, Params: []string{auth}, Sensitive: true})
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if i-1 == len(auth) && len(auth[i]) == 400 {
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if len(auth) == 400 {
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c.write(&Event{Command: AUTHENTICATE, Params: []string{"+"}})
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}
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break
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}
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return
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}
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return
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}
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// ErrAuthSASL is returned when the client is unable to successfully auth
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// via the provided SASL mechanisms.
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type ErrAuthSASL struct {
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Method string // Method is the mechanism.
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Cmd string // Cmd is the SASL command.
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Text string // Text is the trailing text that followed the command if any.
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}
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// Error returns a stringified version of ErrAuthSASL.
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func (e *ErrAuthSASL) Error() string {
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return fmt.Sprintf("unable to use SASL %s authentication: %s (%s)", e.Method, e.Cmd, e.Text)
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}
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func handleSASLError(c *Client, e Event) {
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if c.Config.SASL != nil {
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if c.Config.SASL == nil {
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c.write(&Event{Command: CAP, Params: []string{CAP_END}})
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return
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}
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// This is supposed to panic. Per the IRCv3 spec, one must disconnect upon
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// authentication error. Maybe though, just a QUIT would be better?
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panic(fmt.Sprintf("unable to use SASL %s authentication: %s (%s)", c.Config.SASL.Method(), e.Command, e.Trailing))
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// authentication error. One can avoid disconnecting by handling this
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// error using a Config.RecoverFunc.
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panic(ErrAuthSASL{Method: c.Config.SASL.Method(), Cmd: e.Command, Text: e.Trailing})
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}
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// handleCHGHOST handles incoming IRCv3 hostname change events. CHGHOST is
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