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gitea/routers/web/auth/oauth2_provider.go
Marcell Mars a3881ffa3d
Enhancing Gitea OAuth2 Provider with Granular Scopes for Resource Access (#32573)
Resolve #31609

This PR was initiated following my personal research to find the
lightest possible Single Sign-On solution for self-hosted setups. The
existing solutions often seemed too enterprise-oriented, involving many
moving parts and services, demanding significant resources while
promising planetary-scale capabilities. Others were adequate in
supporting basic OAuth2 flows but lacked proper user management
features, such as a change password UI.

Gitea hits the sweet spot for me, provided it supports more granular
access permissions for resources under users who accept the OAuth2
application.

This PR aims to introduce granularity in handling user resources as
nonintrusively and simply as possible. It allows third parties to inform
users about their intent to not ask for the full access and instead
request a specific, reduced scope. If the provided scopes are **only**
the typical ones for OIDC/OAuth2—`openid`, `profile`, `email`, and
`groups`—everything remains unchanged (currently full access to user's
resources). Additionally, this PR supports processing scopes already
introduced with [personal
tokens](https://docs.gitea.com/development/oauth2-provider#scopes) (e.g.
`read:user`, `write:issue`, `read:group`, `write:repository`...)

Personal tokens define scopes around specific resources: user info,
repositories, issues, packages, organizations, notifications,
miscellaneous, admin, and activitypub, with access delineated by read
and/or write permissions.

The initial case I wanted to address was to have Gitea act as an OAuth2
Identity Provider. To achieve that, with this PR, I would only add
`openid public-only` to provide access token to the third party to
authenticate the Gitea's user but no further access to the API and users
resources.

Another example: if a third party wanted to interact solely with Issues,
it would need to add `read:user` (for authorization) and
`read:issue`/`write:issue` to manage Issues.

My approach is based on my understanding of how scopes can be utilized,
supported by examples like [Sample Use Cases: Scopes and
Claims](https://auth0.com/docs/get-started/apis/scopes/sample-use-cases-scopes-and-claims)
on auth0.com.

I renamed `CheckOAuthAccessToken` to `GetOAuthAccessTokenScopeAndUserID`
so now it returns AccessTokenScope and user's ID. In the case of
additional scopes in `userIDFromToken` the default `all` would be
reduced to whatever was asked via those scopes. The main difference is
the opportunity to reduce the permissions from `all`, as is currently
the case, to what is provided by the additional scopes described above.

Screenshots:

![Screenshot_20241121_121405](https://github.com/user-attachments/assets/29deaed7-4333-4b02-8898-b822e6f2463e)

![Screenshot_20241121_120211](https://github.com/user-attachments/assets/7a4a4ef7-409c-4116-9d5f-2fe00eb37167)

![Screenshot_20241121_120119](https://github.com/user-attachments/assets/aa52c1a2-212d-4e64-bcdf-7122cee49eb6)

![Screenshot_20241121_120018](https://github.com/user-attachments/assets/9eac318c-e381-4ea9-9e2c-3a3f60319e47)
---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
2024-11-22 12:06:41 +08:00

681 lines
24 KiB
Go

// Copyright 2024 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package auth
import (
"errors"
"fmt"
"html"
"html/template"
"net/http"
"net/url"
"strings"
"code.gitea.io/gitea/models/auth"
user_model "code.gitea.io/gitea/models/user"
"code.gitea.io/gitea/modules/base"
"code.gitea.io/gitea/modules/json"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/setting"
"code.gitea.io/gitea/modules/web"
auth_service "code.gitea.io/gitea/services/auth"
"code.gitea.io/gitea/services/context"
"code.gitea.io/gitea/services/forms"
"code.gitea.io/gitea/services/oauth2_provider"
"gitea.com/go-chi/binding"
jwt "github.com/golang-jwt/jwt/v5"
)
const (
tplGrantAccess base.TplName = "user/auth/grant"
tplGrantError base.TplName = "user/auth/grant_error"
)
// TODO move error and responses to SDK or models
// AuthorizeErrorCode represents an error code specified in RFC 6749
// https://datatracker.ietf.org/doc/html/rfc6749#section-4.2.2.1
type AuthorizeErrorCode string
const (
// ErrorCodeInvalidRequest represents the according error in RFC 6749
ErrorCodeInvalidRequest AuthorizeErrorCode = "invalid_request"
// ErrorCodeUnauthorizedClient represents the according error in RFC 6749
ErrorCodeUnauthorizedClient AuthorizeErrorCode = "unauthorized_client"
// ErrorCodeAccessDenied represents the according error in RFC 6749
ErrorCodeAccessDenied AuthorizeErrorCode = "access_denied"
// ErrorCodeUnsupportedResponseType represents the according error in RFC 6749
ErrorCodeUnsupportedResponseType AuthorizeErrorCode = "unsupported_response_type"
// ErrorCodeInvalidScope represents the according error in RFC 6749
ErrorCodeInvalidScope AuthorizeErrorCode = "invalid_scope"
// ErrorCodeServerError represents the according error in RFC 6749
ErrorCodeServerError AuthorizeErrorCode = "server_error"
// ErrorCodeTemporaryUnavailable represents the according error in RFC 6749
ErrorCodeTemporaryUnavailable AuthorizeErrorCode = "temporarily_unavailable"
)
// AuthorizeError represents an error type specified in RFC 6749
// https://datatracker.ietf.org/doc/html/rfc6749#section-4.2.2.1
type AuthorizeError struct {
ErrorCode AuthorizeErrorCode `json:"error" form:"error"`
ErrorDescription string
State string
}
// Error returns the error message
func (err AuthorizeError) Error() string {
return fmt.Sprintf("%s: %s", err.ErrorCode, err.ErrorDescription)
}
// errCallback represents a oauth2 callback error
type errCallback struct {
Code string
Description string
}
func (err errCallback) Error() string {
return err.Description
}
type userInfoResponse struct {
Sub string `json:"sub"`
Name string `json:"name"`
PreferredUsername string `json:"preferred_username"`
Email string `json:"email"`
Picture string `json:"picture"`
Groups []string `json:"groups"`
}
// InfoOAuth manages request for userinfo endpoint
func InfoOAuth(ctx *context.Context) {
if ctx.Doer == nil || ctx.Data["AuthedMethod"] != (&auth_service.OAuth2{}).Name() {
ctx.Resp.Header().Set("WWW-Authenticate", `Bearer realm="Gitea OAuth2"`)
ctx.PlainText(http.StatusUnauthorized, "no valid authorization")
return
}
response := &userInfoResponse{
Sub: fmt.Sprint(ctx.Doer.ID),
Name: ctx.Doer.DisplayName(),
PreferredUsername: ctx.Doer.Name,
Email: ctx.Doer.Email,
Picture: ctx.Doer.AvatarLink(ctx),
}
var accessTokenScope auth.AccessTokenScope
if auHead := ctx.Req.Header.Get("Authorization"); auHead != "" {
auths := strings.Fields(auHead)
if len(auths) == 2 && (auths[0] == "token" || strings.ToLower(auths[0]) == "bearer") {
accessTokenScope, _ = auth_service.GetOAuthAccessTokenScopeAndUserID(ctx, auths[1])
}
}
// since version 1.22 does not verify if groups should be public-only,
// onlyPublicGroups will be set only if 'public-only' is included in a valid scope
onlyPublicGroups, _ := accessTokenScope.PublicOnly()
groups, err := oauth2_provider.GetOAuthGroupsForUser(ctx, ctx.Doer, onlyPublicGroups)
if err != nil {
ctx.ServerError("Oauth groups for user", err)
return
}
response.Groups = groups
ctx.JSON(http.StatusOK, response)
}
func parseBasicAuth(ctx *context.Context) (username, password string, err error) {
authHeader := ctx.Req.Header.Get("Authorization")
if authType, authData, ok := strings.Cut(authHeader, " "); ok && strings.EqualFold(authType, "Basic") {
return base.BasicAuthDecode(authData)
}
return "", "", errors.New("invalid basic authentication")
}
// IntrospectOAuth introspects an oauth token
func IntrospectOAuth(ctx *context.Context) {
clientIDValid := false
if clientID, clientSecret, err := parseBasicAuth(ctx); err == nil {
app, err := auth.GetOAuth2ApplicationByClientID(ctx, clientID)
if err != nil && !auth.IsErrOauthClientIDInvalid(err) {
// this is likely a database error; log it and respond without details
log.Error("Error retrieving client_id: %v", err)
ctx.Error(http.StatusInternalServerError)
return
}
clientIDValid = err == nil && app.ValidateClientSecret([]byte(clientSecret))
}
if !clientIDValid {
ctx.Resp.Header().Set("WWW-Authenticate", `Basic realm="Gitea OAuth2"`)
ctx.PlainText(http.StatusUnauthorized, "no valid authorization")
return
}
var response struct {
Active bool `json:"active"`
Scope string `json:"scope,omitempty"`
Username string `json:"username,omitempty"`
jwt.RegisteredClaims
}
form := web.GetForm(ctx).(*forms.IntrospectTokenForm)
token, err := oauth2_provider.ParseToken(form.Token, oauth2_provider.DefaultSigningKey)
if err == nil {
grant, err := auth.GetOAuth2GrantByID(ctx, token.GrantID)
if err == nil && grant != nil {
app, err := auth.GetOAuth2ApplicationByID(ctx, grant.ApplicationID)
if err == nil && app != nil {
response.Active = true
response.Scope = grant.Scope
response.Issuer = setting.AppURL
response.Audience = []string{app.ClientID}
response.Subject = fmt.Sprint(grant.UserID)
}
if user, err := user_model.GetUserByID(ctx, grant.UserID); err == nil {
response.Username = user.Name
}
}
}
ctx.JSON(http.StatusOK, response)
}
// AuthorizeOAuth manages authorize requests
func AuthorizeOAuth(ctx *context.Context) {
form := web.GetForm(ctx).(*forms.AuthorizationForm)
errs := binding.Errors{}
errs = form.Validate(ctx.Req, errs)
if len(errs) > 0 {
errstring := ""
for _, e := range errs {
errstring += e.Error() + "\n"
}
ctx.ServerError("AuthorizeOAuth: Validate: ", fmt.Errorf("errors occurred during validation: %s", errstring))
return
}
app, err := auth.GetOAuth2ApplicationByClientID(ctx, form.ClientID)
if err != nil {
if auth.IsErrOauthClientIDInvalid(err) {
handleAuthorizeError(ctx, AuthorizeError{
ErrorCode: ErrorCodeUnauthorizedClient,
ErrorDescription: "Client ID not registered",
State: form.State,
}, "")
return
}
ctx.ServerError("GetOAuth2ApplicationByClientID", err)
return
}
var user *user_model.User
if app.UID != 0 {
user, err = user_model.GetUserByID(ctx, app.UID)
if err != nil {
ctx.ServerError("GetUserByID", err)
return
}
}
if !app.ContainsRedirectURI(form.RedirectURI) {
handleAuthorizeError(ctx, AuthorizeError{
ErrorCode: ErrorCodeInvalidRequest,
ErrorDescription: "Unregistered Redirect URI",
State: form.State,
}, "")
return
}
if form.ResponseType != "code" {
handleAuthorizeError(ctx, AuthorizeError{
ErrorCode: ErrorCodeUnsupportedResponseType,
ErrorDescription: "Only code response type is supported.",
State: form.State,
}, form.RedirectURI)
return
}
// pkce support
switch form.CodeChallengeMethod {
case "S256":
case "plain":
if err := ctx.Session.Set("CodeChallengeMethod", form.CodeChallengeMethod); err != nil {
handleAuthorizeError(ctx, AuthorizeError{
ErrorCode: ErrorCodeServerError,
ErrorDescription: "cannot set code challenge method",
State: form.State,
}, form.RedirectURI)
return
}
if err := ctx.Session.Set("CodeChallengeMethod", form.CodeChallenge); err != nil {
handleAuthorizeError(ctx, AuthorizeError{
ErrorCode: ErrorCodeServerError,
ErrorDescription: "cannot set code challenge",
State: form.State,
}, form.RedirectURI)
return
}
// Here we're just going to try to release the session early
if err := ctx.Session.Release(); err != nil {
// we'll tolerate errors here as they *should* get saved elsewhere
log.Error("Unable to save changes to the session: %v", err)
}
case "":
// "Authorization servers SHOULD reject authorization requests from native apps that don't use PKCE by returning an error message"
// https://datatracker.ietf.org/doc/html/rfc8252#section-8.1
if !app.ConfidentialClient {
// "the authorization endpoint MUST return the authorization error response with the "error" value set to "invalid_request""
// https://datatracker.ietf.org/doc/html/rfc7636#section-4.4.1
handleAuthorizeError(ctx, AuthorizeError{
ErrorCode: ErrorCodeInvalidRequest,
ErrorDescription: "PKCE is required for public clients",
State: form.State,
}, form.RedirectURI)
return
}
default:
// "If the server supporting PKCE does not support the requested transformation, the authorization endpoint MUST return the authorization error response with "error" value set to "invalid_request"."
// https://www.rfc-editor.org/rfc/rfc7636#section-4.4.1
handleAuthorizeError(ctx, AuthorizeError{
ErrorCode: ErrorCodeInvalidRequest,
ErrorDescription: "unsupported code challenge method",
State: form.State,
}, form.RedirectURI)
return
}
grant, err := app.GetGrantByUserID(ctx, ctx.Doer.ID)
if err != nil {
handleServerError(ctx, form.State, form.RedirectURI)
return
}
// Redirect if user already granted access and the application is confidential or trusted otherwise
// I.e. always require authorization for untrusted public clients as recommended by RFC 6749 Section 10.2
if (app.ConfidentialClient || app.SkipSecondaryAuthorization) && grant != nil {
code, err := grant.GenerateNewAuthorizationCode(ctx, form.RedirectURI, form.CodeChallenge, form.CodeChallengeMethod)
if err != nil {
handleServerError(ctx, form.State, form.RedirectURI)
return
}
redirect, err := code.GenerateRedirectURI(form.State)
if err != nil {
handleServerError(ctx, form.State, form.RedirectURI)
return
}
// Update nonce to reflect the new session
if len(form.Nonce) > 0 {
err := grant.SetNonce(ctx, form.Nonce)
if err != nil {
log.Error("Unable to update nonce: %v", err)
}
}
ctx.Redirect(redirect.String())
return
}
// check if additional scopes
ctx.Data["AdditionalScopes"] = oauth2_provider.GrantAdditionalScopes(form.Scope) != auth.AccessTokenScopeAll
// show authorize page to grant access
ctx.Data["Application"] = app
ctx.Data["RedirectURI"] = form.RedirectURI
ctx.Data["State"] = form.State
ctx.Data["Scope"] = form.Scope
ctx.Data["Nonce"] = form.Nonce
if user != nil {
ctx.Data["ApplicationCreatorLinkHTML"] = template.HTML(fmt.Sprintf(`<a href="%s">@%s</a>`, html.EscapeString(user.HomeLink()), html.EscapeString(user.Name)))
} else {
ctx.Data["ApplicationCreatorLinkHTML"] = template.HTML(fmt.Sprintf(`<a href="%s">%s</a>`, html.EscapeString(setting.AppSubURL+"/"), html.EscapeString(setting.AppName)))
}
ctx.Data["ApplicationRedirectDomainHTML"] = template.HTML("<strong>" + html.EscapeString(form.RedirectURI) + "</strong>")
// TODO document SESSION <=> FORM
err = ctx.Session.Set("client_id", app.ClientID)
if err != nil {
handleServerError(ctx, form.State, form.RedirectURI)
log.Error(err.Error())
return
}
err = ctx.Session.Set("redirect_uri", form.RedirectURI)
if err != nil {
handleServerError(ctx, form.State, form.RedirectURI)
log.Error(err.Error())
return
}
err = ctx.Session.Set("state", form.State)
if err != nil {
handleServerError(ctx, form.State, form.RedirectURI)
log.Error(err.Error())
return
}
// Here we're just going to try to release the session early
if err := ctx.Session.Release(); err != nil {
// we'll tolerate errors here as they *should* get saved elsewhere
log.Error("Unable to save changes to the session: %v", err)
}
ctx.HTML(http.StatusOK, tplGrantAccess)
}
// GrantApplicationOAuth manages the post request submitted when a user grants access to an application
func GrantApplicationOAuth(ctx *context.Context) {
form := web.GetForm(ctx).(*forms.GrantApplicationForm)
if ctx.Session.Get("client_id") != form.ClientID || ctx.Session.Get("state") != form.State ||
ctx.Session.Get("redirect_uri") != form.RedirectURI {
ctx.Error(http.StatusBadRequest)
return
}
if !form.Granted {
handleAuthorizeError(ctx, AuthorizeError{
State: form.State,
ErrorDescription: "the request is denied",
ErrorCode: ErrorCodeAccessDenied,
}, form.RedirectURI)
return
}
app, err := auth.GetOAuth2ApplicationByClientID(ctx, form.ClientID)
if err != nil {
ctx.ServerError("GetOAuth2ApplicationByClientID", err)
return
}
grant, err := app.GetGrantByUserID(ctx, ctx.Doer.ID)
if err != nil {
handleServerError(ctx, form.State, form.RedirectURI)
return
}
if grant == nil {
grant, err = app.CreateGrant(ctx, ctx.Doer.ID, form.Scope)
if err != nil {
handleAuthorizeError(ctx, AuthorizeError{
State: form.State,
ErrorDescription: "cannot create grant for user",
ErrorCode: ErrorCodeServerError,
}, form.RedirectURI)
return
}
} else if grant.Scope != form.Scope {
handleAuthorizeError(ctx, AuthorizeError{
State: form.State,
ErrorDescription: "a grant exists with different scope",
ErrorCode: ErrorCodeServerError,
}, form.RedirectURI)
return
}
if len(form.Nonce) > 0 {
err := grant.SetNonce(ctx, form.Nonce)
if err != nil {
log.Error("Unable to update nonce: %v", err)
}
}
var codeChallenge, codeChallengeMethod string
codeChallenge, _ = ctx.Session.Get("CodeChallenge").(string)
codeChallengeMethod, _ = ctx.Session.Get("CodeChallengeMethod").(string)
code, err := grant.GenerateNewAuthorizationCode(ctx, form.RedirectURI, codeChallenge, codeChallengeMethod)
if err != nil {
handleServerError(ctx, form.State, form.RedirectURI)
return
}
redirect, err := code.GenerateRedirectURI(form.State)
if err != nil {
handleServerError(ctx, form.State, form.RedirectURI)
return
}
ctx.Redirect(redirect.String(), http.StatusSeeOther)
}
// OIDCWellKnown generates JSON so OIDC clients know Gitea's capabilities
func OIDCWellKnown(ctx *context.Context) {
ctx.Data["SigningKey"] = oauth2_provider.DefaultSigningKey
ctx.JSONTemplate("user/auth/oidc_wellknown")
}
// OIDCKeys generates the JSON Web Key Set
func OIDCKeys(ctx *context.Context) {
jwk, err := oauth2_provider.DefaultSigningKey.ToJWK()
if err != nil {
log.Error("Error converting signing key to JWK: %v", err)
ctx.Error(http.StatusInternalServerError)
return
}
jwk["use"] = "sig"
jwks := map[string][]map[string]string{
"keys": {
jwk,
},
}
ctx.Resp.Header().Set("Content-Type", "application/json")
enc := json.NewEncoder(ctx.Resp)
if err := enc.Encode(jwks); err != nil {
log.Error("Failed to encode representation as json. Error: %v", err)
}
}
// AccessTokenOAuth manages all access token requests by the client
func AccessTokenOAuth(ctx *context.Context) {
form := *web.GetForm(ctx).(*forms.AccessTokenForm)
// if there is no ClientID or ClientSecret in the request body, fill these fields by the Authorization header and ensure the provided field matches the Authorization header
if form.ClientID == "" || form.ClientSecret == "" {
authHeader := ctx.Req.Header.Get("Authorization")
if authType, authData, ok := strings.Cut(authHeader, " "); ok && strings.EqualFold(authType, "Basic") {
clientID, clientSecret, err := base.BasicAuthDecode(authData)
if err != nil {
handleAccessTokenError(ctx, oauth2_provider.AccessTokenError{
ErrorCode: oauth2_provider.AccessTokenErrorCodeInvalidRequest,
ErrorDescription: "cannot parse basic auth header",
})
return
}
// validate that any fields present in the form match the Basic auth header
if form.ClientID != "" && form.ClientID != clientID {
handleAccessTokenError(ctx, oauth2_provider.AccessTokenError{
ErrorCode: oauth2_provider.AccessTokenErrorCodeInvalidRequest,
ErrorDescription: "client_id in request body inconsistent with Authorization header",
})
return
}
form.ClientID = clientID
if form.ClientSecret != "" && form.ClientSecret != clientSecret {
handleAccessTokenError(ctx, oauth2_provider.AccessTokenError{
ErrorCode: oauth2_provider.AccessTokenErrorCodeInvalidRequest,
ErrorDescription: "client_secret in request body inconsistent with Authorization header",
})
return
}
form.ClientSecret = clientSecret
}
}
serverKey := oauth2_provider.DefaultSigningKey
clientKey := serverKey
if serverKey.IsSymmetric() {
var err error
clientKey, err = oauth2_provider.CreateJWTSigningKey(serverKey.SigningMethod().Alg(), []byte(form.ClientSecret))
if err != nil {
handleAccessTokenError(ctx, oauth2_provider.AccessTokenError{
ErrorCode: oauth2_provider.AccessTokenErrorCodeInvalidRequest,
ErrorDescription: "Error creating signing key",
})
return
}
}
switch form.GrantType {
case "refresh_token":
handleRefreshToken(ctx, form, serverKey, clientKey)
case "authorization_code":
handleAuthorizationCode(ctx, form, serverKey, clientKey)
default:
handleAccessTokenError(ctx, oauth2_provider.AccessTokenError{
ErrorCode: oauth2_provider.AccessTokenErrorCodeUnsupportedGrantType,
ErrorDescription: "Only refresh_token or authorization_code grant type is supported",
})
}
}
func handleRefreshToken(ctx *context.Context, form forms.AccessTokenForm, serverKey, clientKey oauth2_provider.JWTSigningKey) {
app, err := auth.GetOAuth2ApplicationByClientID(ctx, form.ClientID)
if err != nil {
handleAccessTokenError(ctx, oauth2_provider.AccessTokenError{
ErrorCode: oauth2_provider.AccessTokenErrorCodeInvalidClient,
ErrorDescription: fmt.Sprintf("cannot load client with client id: %q", form.ClientID),
})
return
}
// "The authorization server MUST ... require client authentication for confidential clients"
// https://datatracker.ietf.org/doc/html/rfc6749#section-6
if app.ConfidentialClient && !app.ValidateClientSecret([]byte(form.ClientSecret)) {
errorDescription := "invalid client secret"
if form.ClientSecret == "" {
errorDescription = "invalid empty client secret"
}
// "invalid_client ... Client authentication failed"
// https://datatracker.ietf.org/doc/html/rfc6749#section-5.2
handleAccessTokenError(ctx, oauth2_provider.AccessTokenError{
ErrorCode: oauth2_provider.AccessTokenErrorCodeInvalidClient,
ErrorDescription: errorDescription,
})
return
}
token, err := oauth2_provider.ParseToken(form.RefreshToken, serverKey)
if err != nil {
handleAccessTokenError(ctx, oauth2_provider.AccessTokenError{
ErrorCode: oauth2_provider.AccessTokenErrorCodeUnauthorizedClient,
ErrorDescription: "unable to parse refresh token",
})
return
}
// get grant before increasing counter
grant, err := auth.GetOAuth2GrantByID(ctx, token.GrantID)
if err != nil || grant == nil {
handleAccessTokenError(ctx, oauth2_provider.AccessTokenError{
ErrorCode: oauth2_provider.AccessTokenErrorCodeInvalidGrant,
ErrorDescription: "grant does not exist",
})
return
}
// check if token got already used
if setting.OAuth2.InvalidateRefreshTokens && (grant.Counter != token.Counter || token.Counter == 0) {
handleAccessTokenError(ctx, oauth2_provider.AccessTokenError{
ErrorCode: oauth2_provider.AccessTokenErrorCodeUnauthorizedClient,
ErrorDescription: "token was already used",
})
log.Warn("A client tried to use a refresh token for grant_id = %d was used twice!", grant.ID)
return
}
accessToken, tokenErr := oauth2_provider.NewAccessTokenResponse(ctx, grant, serverKey, clientKey)
if tokenErr != nil {
handleAccessTokenError(ctx, *tokenErr)
return
}
ctx.JSON(http.StatusOK, accessToken)
}
func handleAuthorizationCode(ctx *context.Context, form forms.AccessTokenForm, serverKey, clientKey oauth2_provider.JWTSigningKey) {
app, err := auth.GetOAuth2ApplicationByClientID(ctx, form.ClientID)
if err != nil {
handleAccessTokenError(ctx, oauth2_provider.AccessTokenError{
ErrorCode: oauth2_provider.AccessTokenErrorCodeInvalidClient,
ErrorDescription: fmt.Sprintf("cannot load client with client id: '%s'", form.ClientID),
})
return
}
if app.ConfidentialClient && !app.ValidateClientSecret([]byte(form.ClientSecret)) {
errorDescription := "invalid client secret"
if form.ClientSecret == "" {
errorDescription = "invalid empty client secret"
}
handleAccessTokenError(ctx, oauth2_provider.AccessTokenError{
ErrorCode: oauth2_provider.AccessTokenErrorCodeUnauthorizedClient,
ErrorDescription: errorDescription,
})
return
}
if form.RedirectURI != "" && !app.ContainsRedirectURI(form.RedirectURI) {
handleAccessTokenError(ctx, oauth2_provider.AccessTokenError{
ErrorCode: oauth2_provider.AccessTokenErrorCodeUnauthorizedClient,
ErrorDescription: "unexpected redirect URI",
})
return
}
authorizationCode, err := auth.GetOAuth2AuthorizationByCode(ctx, form.Code)
if err != nil || authorizationCode == nil {
handleAccessTokenError(ctx, oauth2_provider.AccessTokenError{
ErrorCode: oauth2_provider.AccessTokenErrorCodeUnauthorizedClient,
ErrorDescription: "client is not authorized",
})
return
}
// check if code verifier authorizes the client, PKCE support
if !authorizationCode.ValidateCodeChallenge(form.CodeVerifier) {
handleAccessTokenError(ctx, oauth2_provider.AccessTokenError{
ErrorCode: oauth2_provider.AccessTokenErrorCodeUnauthorizedClient,
ErrorDescription: "failed PKCE code challenge",
})
return
}
// check if granted for this application
if authorizationCode.Grant.ApplicationID != app.ID {
handleAccessTokenError(ctx, oauth2_provider.AccessTokenError{
ErrorCode: oauth2_provider.AccessTokenErrorCodeInvalidGrant,
ErrorDescription: "invalid grant",
})
return
}
// remove token from database to deny duplicate usage
if err := authorizationCode.Invalidate(ctx); err != nil {
handleAccessTokenError(ctx, oauth2_provider.AccessTokenError{
ErrorCode: oauth2_provider.AccessTokenErrorCodeInvalidRequest,
ErrorDescription: "cannot proceed your request",
})
}
resp, tokenErr := oauth2_provider.NewAccessTokenResponse(ctx, authorizationCode.Grant, serverKey, clientKey)
if tokenErr != nil {
handleAccessTokenError(ctx, *tokenErr)
return
}
// send successful response
ctx.JSON(http.StatusOK, resp)
}
func handleAccessTokenError(ctx *context.Context, acErr oauth2_provider.AccessTokenError) {
ctx.JSON(http.StatusBadRequest, acErr)
}
func handleServerError(ctx *context.Context, state, redirectURI string) {
handleAuthorizeError(ctx, AuthorizeError{
ErrorCode: ErrorCodeServerError,
ErrorDescription: "A server error occurred",
State: state,
}, redirectURI)
}
func handleAuthorizeError(ctx *context.Context, authErr AuthorizeError, redirectURI string) {
if redirectURI == "" {
log.Warn("Authorization failed: %v", authErr.ErrorDescription)
ctx.Data["Error"] = authErr
ctx.HTML(http.StatusBadRequest, tplGrantError)
return
}
redirect, err := url.Parse(redirectURI)
if err != nil {
ctx.ServerError("url.Parse", err)
return
}
q := redirect.Query()
q.Set("error", string(authErr.ErrorCode))
q.Set("error_description", authErr.ErrorDescription)
q.Set("state", authErr.State)
redirect.RawQuery = q.Encode()
ctx.Redirect(redirect.String(), http.StatusSeeOther)
}