Hi… I am well aware that this diff view is very suboptimal. It will be fixed when the refactored server comes along!
Fix nil deref when introspection a public client token
package main
import (
"encoding/json"
"errors"
"fmt"
"io"
"log"
"mime"
"net"
"net/http"
"net/url"
"strings"
"time"
"git.sr.ht/~emersion/go-oauth2"
)
func getOAuthServerMetadata(w http.ResponseWriter, req *http.Request) {
issuerURL := url.URL{
Scheme: "https",
Host: req.Host,
}
if !isForwardedHTTPS(req) && isLoopback(req) {
// TODO: add config option for allowed reverse proxy IPs
issuerURL.Scheme = "http"
}
issuer := issuerURL.String()
w.Header().Set("Content-Type", "application/json")
json.NewEncoder(w).Encode(&oauth2.ServerMetadata{
Issuer: issuer,
AuthorizationEndpoint: issuer + "/authorize",
TokenEndpoint: issuer + "/token",
IntrospectionEndpoint: issuer + "/introspect",
ResponseTypesSupported: []oauth2.ResponseType{oauth2.ResponseTypeCode},
ResponseModesSupported: []oauth2.ResponseMode{oauth2.ResponseModeQuery},
GrantTypesSupported: []oauth2.GrantType{oauth2.GrantTypeAuthorizationCode},
TokenEndpointAuthMethodsSupported: []oauth2.AuthMethod{oauth2.AuthMethodClientSecretBasic},
IntrospectionEndpointAuthMethodsSupported: []oauth2.AuthMethod{oauth2.AuthMethodClientSecretBasic},
})
}
func isLoopback(req *http.Request) bool {
host, _, _ := net.SplitHostPort(req.RemoteAddr)
ip := net.ParseIP(host)
return ip.IsLoopback()
}
func authorize(w http.ResponseWriter, req *http.Request) {
ctx := req.Context()
db := dbFromContext(ctx)
tpl := templateFromContext(ctx)
q := req.URL.Query()
respType := oauth2.ResponseType(q.Get("response_type"))
clientID := q.Get("client_id")
rawRedirectURI := q.Get("redirect_uri")
scope := q.Get("scope")
state := q.Get("state")
if clientID == "" {
http.Error(w, "Missing client ID", http.StatusBadRequest)
return
}
client, err := db.FetchClientByClientID(ctx, clientID)
if err == errNoDBRows {
http.Error(w, "Invalid client ID", http.StatusForbidden)
return
} else if err != nil {
httpError(w, fmt.Errorf("failed to fetch client: %v", err))
return
}
var allowedRedirectURIs []*url.URL
for _, s := range strings.Split(client.RedirectURIs, "\n") {
if s == "" {
continue
}
u, err := url.Parse(s)
if err != nil {
httpError(w, fmt.Errorf("failed to parse client redirect URI"))
return
}
allowedRedirectURIs = append(allowedRedirectURIs, u)
}
var redirectURI *url.URL
if rawRedirectURI != "" {
redirectURI, err = url.Parse(rawRedirectURI)
if err != nil {
http.Error(w, "Invalid redirect URI", http.StatusBadRequest)
return
}
if !validateRedirectURI(redirectURI, allowedRedirectURIs) {
http.Error(w, "Invalid redirect URI", http.StatusBadRequest)
return
}
} else {
if len(allowedRedirectURIs) == 0 {
http.Error(w, "Missing redirect URI", http.StatusBadRequest)
return
}
redirectURI = allowedRedirectURIs[0]
}
if respType != oauth2.ResponseTypeCode {
redirectClientError(w, req, redirectURI, state, &oauth2.Error{
Code: oauth2.ErrorCodeUnsupportedResponseType,
})
return
}
// TODO: add support for scope
if scope != "" {
redirectClientError(w, req, redirectURI, state, &oauth2.Error{
Code: oauth2.ErrorCodeInvalidScope,
})
return
}
loginToken := loginTokenFromContext(ctx)
if loginToken == nil {
q := make(url.Values)
q.Set("redirect_uri", req.URL.String())
u := url.URL{
Path: "/login",
RawQuery: q.Encode(),
}
http.Redirect(w, req, u.String(), http.StatusFound)
return
}
_ = req.ParseForm()
if _, ok := req.PostForm["deny"]; ok {
redirectClientError(w, req, redirectURI, state, &oauth2.Error{
Code: oauth2.ErrorCodeAccessDenied,
})
return
}
if _, ok := req.PostForm["authorize"]; !ok {
data := struct {
Client *Client
}{
Client: client,
}
if err := tpl.ExecuteTemplate(w, "authorize.html", data); err != nil {
panic(err)
}
return
}
authCode, secret, err := NewAuthCode(loginToken.User, client.ID, scope)
if err != nil {
httpError(w, fmt.Errorf("failed to generate authentication code: %v", err))
return
}
if err := db.CreateAuthCode(ctx, authCode); err != nil {
httpError(w, fmt.Errorf("failed to create authentication code: %v", err))
return
}
code := MarshalSecret(authCode.ID, secret)
values := make(url.Values)
values.Set("code", code)
if state != "" {
values.Set("state", state)
}
redirectClient(w, req, redirectURI, values)
}
func exchangeToken(w http.ResponseWriter, req *http.Request) {
ctx := req.Context()
db := dbFromContext(ctx)
values, err := parseRequestBody(req)
if err != nil {
oauthError(w, &oauth2.Error{
Code: oauth2.ErrorCodeInvalidRequest,
Description: err.Error(),
})
return
}
clientID := values.Get("client_id")
grantType := oauth2.GrantType(values.Get("grant_type"))
scope := values.Get("scope")
authClientID, clientSecret, _ := req.BasicAuth()
if clientID == "" && authClientID == "" {
oauthError(w, &oauth2.Error{
Code: oauth2.ErrorCodeInvalidRequest,
Description: "Missing client ID",
})
return
} else if clientID == "" {
clientID = authClientID
} else if clientID != authClientID {
oauthError(w, &oauth2.Error{
Code: oauth2.ErrorCodeInvalidRequest,
Description: "Client ID in request body doesn't match Authorization header field",
})
return
}
client, err := db.FetchClientByClientID(ctx, clientID)
if err == errNoDBRows {
oauthError(w, &oauth2.Error{
Code: oauth2.ErrorCodeInvalidClient,
Description: "Invalid client ID",
})
return
} else if err != nil {
oauthError(w, fmt.Errorf("failed to fetch client: %v", err))
return
}
if !client.IsPublic() {
if !client.VerifySecret(clientSecret) {
oauthError(w, &oauth2.Error{
Code: oauth2.ErrorCodeAccessDenied,
Description: "Invalid client secret",
})
return
}
}
if grantType != oauth2.GrantTypeAuthorizationCode {
oauthError(w, &oauth2.Error{
Code: oauth2.ErrorCodeUnsupportedGrantType,
Description: "Unsupported grant type",
})
return
}
codeID, codeSecret, _ := UnmarshalSecret[*AuthCode](values.Get("code"))
authCode, err := db.PopAuthCode(ctx, codeID)
if err == errNoDBRows || (err == nil && !authCode.VerifySecret(codeSecret)) || authCode.Client != client.ID {
oauthError(w, &oauth2.Error{
Code: oauth2.ErrorCodeAccessDenied,
Description: "Invalid authorization code",
})
return
} else if err != nil {
oauthError(w, fmt.Errorf("failed to fetch authorization code: %v", err))
return
}
if scope != authCode.Scope {
oauthError(w, &oauth2.Error{
Code: oauth2.ErrorCodeAccessDenied,
Description: "Invalid scope",
})
return
}
// TODO: check redirect_uri
token, secret, err := NewAccessTokenFromAuthCode(authCode)
if err != nil {
oauthError(w, err)
return
}
if err := db.CreateAccessToken(ctx, token); err != nil {
oauthError(w, fmt.Errorf("failed to create access token: %v", err))
return
}
w.Header().Set("Content-Type", "application/json")
w.Header().Set("Cache-Control", "no-store")
json.NewEncoder(w).Encode(&oauth2.TokenResp{
AccessToken: MarshalSecret(token.ID, secret),
TokenType: oauth2.TokenTypeBearer,
ExpiresIn: time.Until(token.ExpiresAt),
Scope: strings.Split(token.Scope, " "),
})
}
func introspectToken(w http.ResponseWriter, req *http.Request) {
ctx := req.Context()
db := dbFromContext(ctx)
values, err := parseRequestBody(req)
if err != nil {
oauthError(w, &oauth2.Error{
Code: oauth2.ErrorCodeInvalidRequest,
Description: err.Error(),
})
return
}
var client *Client
if clientID, clientSecret, ok := req.BasicAuth(); ok {
client, err = db.FetchClientByClientID(ctx, clientID)
if err == errNoDBRows || (err == nil && !client.VerifySecret(clientSecret)) {
oauthError(w, &oauth2.Error{
Code: oauth2.ErrorCodeInvalidClient,
Description: "Invalid client ID or secret",
})
return
} else if err != nil {
oauthError(w, fmt.Errorf("failed to fetch client: %v", err))
return
}
}
tokenID, secret, _ := UnmarshalSecret[*AccessToken](values.Get("token"))
token, err := db.FetchAccessToken(ctx, tokenID)
if err == errNoDBRows || (err == nil && !token.VerifySecret(secret)) {
token = nil
} else if err != nil {
oauthError(w, fmt.Errorf("failed to fetch access token: %v", err))
return
}
var resp oauth2.IntrospectionResp
if token != nil {
if client == nil {
client, err = db.FetchClient(ctx, token.Client)
if err != nil {
oauthError(w, fmt.Errorf("failed to fetch client: %v", err))
return
}
if !client.IsPublic() {
oauthError(w, &oauth2.Error{
Code: oauth2.ErrorCodeInvalidClient,
Description: "Missing client ID and secret",
})
return
}
client, err = db.FetchClient(ctx, token.Client)
if err != nil {
oauthError(w, fmt.Errorf("failed to fetch client: %v", err))
return
}
}
user, err := db.FetchUser(ctx, token.User)
if err != nil {
oauthError(w, fmt.Errorf("failed to fetch user: %v", err))
return
}
resp.Active = true
resp.TokenType = oauth2.TokenTypeBearer
resp.ExpiresAt = token.ExpiresAt
resp.IssuedAt = token.IssuedAt
resp.ClientID = client.ClientID
resp.Username = user.Username
}
w.Header().Set("Content-Type", "application/json")
json.NewEncoder(w).Encode(&resp)
}
func parseRequestBody(req *http.Request) (url.Values, error) {
ct := req.Header.Get("Content-Type")
if ct != "" {
mimeType, _, err := mime.ParseMediaType(req.Header.Get("Content-Type"))
if err != nil {
return nil, fmt.Errorf("malformed Content-Type header field")
} else if mimeType != "application/x-www-form-urlencoded" {
return nil, fmt.Errorf("unsupported request content type")
}
}
r := io.LimitReader(req.Body, 10<<20)
b, err := io.ReadAll(r)
if err != nil {
return nil, fmt.Errorf("failed to read request body: %v", err)
}
values, err := url.ParseQuery(string(b))
if err != nil {
return nil, fmt.Errorf("failed to parse request body: %v", err)
}
return values, nil
}
func oauthError(w http.ResponseWriter, err error) {
var oauthErr *oauth2.Error
if !errors.As(err, &oauthErr) {
oauthErr = &oauth2.Error{Code: oauth2.ErrorCodeServerError}
log.Print(err)
}
statusCode := http.StatusInternalServerError
switch oauthErr.Code {
case oauth2.ErrorCodeInvalidRequest, oauth2.ErrorCodeUnsupportedResponseType, oauth2.ErrorCodeInvalidScope, oauth2.ErrorCodeInvalidClient, oauth2.ErrorCodeInvalidGrant, oauth2.ErrorCodeUnsupportedGrantType:
statusCode = http.StatusBadRequest
case oauth2.ErrorCodeUnauthorizedClient, oauth2.ErrorCodeAccessDenied:
statusCode = http.StatusForbidden
case oauth2.ErrorCodeTemporarilyUnavailable:
statusCode = http.StatusServiceUnavailable
}
w.Header().Set("Content-Type", "application/json")
w.WriteHeader(statusCode)
json.NewEncoder(w).Encode(oauthErr)
}
func redirectClient(w http.ResponseWriter, req *http.Request, redirectURI *url.URL, values url.Values) {
q := redirectURI.Query()
for k, v := range values {
q[k] = v
}
u := *redirectURI
u.RawQuery = q.Encode()
http.Redirect(w, req, u.String(), http.StatusFound)
}
func redirectClientError(w http.ResponseWriter, req *http.Request, redirectURI *url.URL, state string, err error) {
var oauthErr *oauth2.Error
if !errors.As(err, &oauthErr) {
oauthErr = &oauth2.Error{Code: oauth2.ErrorCodeServerError}
log.Print(err)
}
values := make(url.Values)
values.Set("error", string(oauthErr.Code))
if oauthErr.Description != "" {
values.Set("error_description", oauthErr.Description)
}
if oauthErr.URI != "" {
values.Set("error_uri", oauthErr.URI)
}
if state != "" {
values.Set("state", state)
}
redirectClient(w, req, redirectURI, values)
}
func validateRedirectURI(u *url.URL, allowedURIs []*url.URL) bool {
// Loopback interface, see RFC 8252 section 7.3
host, _, _ := net.SplitHostPort(u.Host)
ip := net.ParseIP(host)
if u.Scheme == "http" && ip.IsLoopback() {
uu := *u
uu.Host = "localhost"
u = &uu
}
for _, allowed := range allowedURIs {
if u.String() == allowed.String() {
return true
}
}
return false
}