/
authexternalbrowser.go
252 lines (229 loc) · 6.59 KB
/
authexternalbrowser.go
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package gosnowflake
//
// Copyright (c) 2019 Snowflake Computing Inc. All right reserved.
//
import (
"bytes"
"encoding/json"
"fmt"
"io"
"io/ioutil"
"log"
"net"
"net/http"
"net/url"
"strconv"
"strings"
"github.com/pkg/browser"
)
const (
successHTML = `<!DOCTYPE html><html><head><meta charset="UTF-8"/>
<title>SAML Response for Snowflake</title></head>
<body>
Your identity was confirmed and propagated to Snowflake %v.
You can close this window now and go back where you started from.
</body></html>`
)
const (
bufSize = 8192
)
// Builds a response to show to the user after successfully
// getting a response from Snowflake.
func buildResponse(application string) bytes.Buffer {
body := fmt.Sprintf(successHTML, application)
t := &http.Response{
Status: "200 OK",
StatusCode: 200,
Proto: "HTTP/1.1",
ProtoMajor: 1,
ProtoMinor: 1,
Body: ioutil.NopCloser(bytes.NewBufferString(body)),
ContentLength: int64(len(body)),
Request: nil,
Header: make(http.Header),
}
var b bytes.Buffer
t.Write(&b)
return b
}
// This opens a socket that listens on all available unicast
// and any anycast IP addresses locally. By specifying "0", we are
// able to bind to a free port.
func bindToPort() (net.Listener, error) {
l, err := net.Listen("tcp", "localhost:0")
if err != nil {
glog.V(1).Infof("unable to bind to a port on localhost, err: %v", err)
return nil, err
}
return l, nil
}
// Opens a browser window (or new tab) with the configured IDP Url.
// This can / will fail if running inside a shell with no display, ie
// ssh'ing into a box attempting to authenticate via external browser.
func openBrowser(idpURL string) error {
err := browser.OpenURL(idpURL)
if err != nil {
glog.V(1).Infof("failed to open a browser. err: %v", err)
return err
}
return nil
}
// Gets the IDP Url and Proof Key from Snowflake.
// Note: FuncPostAuthSaml will return a fully qualified error if
// there is something wrong getting data from Snowflake.
func getIdpURLProofKey(
sr *snowflakeRestful,
authenticator string,
application string,
account string,
callbackPort int) (string, string, error) {
headers := make(map[string]string)
headers["Content-Type"] = headerContentTypeApplicationJSON
headers["accept"] = headerContentTypeApplicationJSON
headers["User-Agent"] = userAgent
clientEnvironment := authRequestClientEnvironment{
Application: application,
Os: operatingSystem,
OsVersion: platform,
}
requestMain := authRequestData{
ClientAppID: clientType,
ClientAppVersion: SnowflakeGoDriverVersion,
AccountName: account,
ClientEnvironment: clientEnvironment,
Authenticator: authenticator,
BrowserModeRedirectPort: strconv.Itoa(callbackPort),
}
authRequest := authRequest{
Data: requestMain,
}
jsonBody, err := json.Marshal(authRequest)
if err != nil {
glog.V(1).Infof("failed to serialize json. err: %v", err)
return "", "", err
}
respd, err := sr.FuncPostAuthSAML(sr, headers, jsonBody, sr.LoginTimeout)
if err != nil {
return "", "", err
}
return respd.Data.SSOURL, respd.Data.ProofKey, nil
}
// The response returned from Snowflake looks like so:
// GET /?token=encodedSamlToken
// Host: localhost:54001
// Connection: keep-alive
// Upgrade-Insecure-Requests: 1
// User-Agent: userAgentStr
// Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8
// Referer: https://myaccount.snowflakecomputing.com/fed/login
// Accept-Encoding: gzip, deflate, br
// Accept-Language: en-US,en;q=0.9
// This extracts the token portion of the response.
func getTokenFromResponse(response string) (string, error) {
start := "GET /?token="
arr := strings.Split(response, "\r\n")
if !strings.HasPrefix(arr[0], start) {
glog.V(1).Infof("response is malformed. resp: %s", arr[0])
return "", &SnowflakeError{
Number: ErrFailedToParseResponse,
SQLState: SQLStateConnectionRejected,
Message: errMsgFailedToParseResponse,
MessageArgs: []interface{}{response},
}
}
token := strings.TrimLeft(arr[0], start)
token = strings.Split(token, " ")[0]
return token, nil
}
// Authentication by an external browser takes place via the following:
// - the golang snowflake driver communicates to Snowflake that the user wishes to
// authenticate via external browser
// - snowflake sends back the IDP Url configured at the Snowflake side for the
// provided account
// - the default browser is opened to that URL
// - user authenticates at the IDP, and is redirected to Snowflake
// - Snowflake directs the user back to the driver
// - authenticate is complete!
func authenticateByExternalBrowser(
sr *snowflakeRestful,
authenticator string,
application string,
account string,
user string,
password string,
) ([]byte, []byte, error) {
l, err := bindToPort()
if err != nil {
return nil, nil, err
}
defer l.Close()
callbackPort := l.Addr().(*net.TCPAddr).Port
idpURL, proofKey, err := getIdpURLProofKey(
sr, authenticator, application, account, callbackPort)
if err != nil {
return nil, nil, err
}
if err = openBrowser(idpURL); err != nil {
return nil, nil, err
}
var encodedSamlResponse string
var acceptErr error
var tokenErr error
acceptErr = nil
for {
conn, err := l.Accept()
if err != nil {
glog.V(1).Infof("unable to accept connection. err: %v", err)
log.Fatal(err)
}
go func(c net.Conn) {
var buf bytes.Buffer
total := 0
for {
b := make([]byte, bufSize)
n, err := c.Read(b)
if err != nil {
if err != io.EOF {
glog.V(1).Infof("error reading from socket. err: %v", err)
acceptErr = err
}
break
}
total += n
buf.Write(b)
if n < bufSize {
// We successfully read all data
s := string(buf.Bytes()[:total])
encodedSamlResponse, tokenErr = getTokenFromResponse(s)
break
}
buf.Grow(bufSize)
}
if encodedSamlResponse != "" {
httpResponse := buildResponse(application)
c.Write(httpResponse.Bytes())
}
c.Close()
}(conn)
if acceptErr != nil || encodedSamlResponse != "" {
break
}
}
if tokenErr != nil {
return nil, nil, tokenErr
}
if acceptErr != nil {
return nil, nil, &SnowflakeError{
Number: ErrFailedToGetExternalBrowserResponse,
SQLState: SQLStateConnectionRejected,
Message: errMsgFailedToGetExternalBrowserResponse,
MessageArgs: []interface{}{acceptErr},
}
}
escapedSamlResponse, err := url.QueryUnescape(encodedSamlResponse)
if err != nil {
glog.V(1).Infof("unable to unescape saml response. err: %v", err)
return nil, nil, err
}
return []byte(escapedSamlResponse), []byte(proofKey), nil
}