Deprecate query string auth tokens (#28390)

## Changes
- Add deprecation warning to `Token` and `AccessToken` authentication
methods in swagger.
- Add deprecation warning header to API response. Example: 
  ```
  HTTP/1.1 200 OK
  ...
  Warning: token and access_token API authentication is deprecated
  ...
  ```
- Add setting `DISABLE_QUERY_AUTH_TOKEN` to reject query string auth
tokens entirely. Default is `false`

## Next steps
- `DISABLE_QUERY_AUTH_TOKEN` should be true in a subsequent release and
the methods should be removed in swagger
- `DISABLE_QUERY_AUTH_TOKEN` should be removed and the implementation of
the auth methods in question should be removed

## Open questions
- Should there be further changes to the swagger documentation?
Deprecation is not yet supported for security definitions (coming in
[OpenAPI Spec version
3.2.0](https://github.com/OAI/OpenAPI-Specification/issues/2506))
- Should the API router logger sanitize urls that use `token` or
`access_token`? (This is obviously an insufficient solution on its own)

---------

Co-authored-by: delvh <dev.lh@web.de>

1 files changed, 13 insertions, 7 deletions

diff --git a/services/auth/oauth2.go b/services/auth/oauth2.go
index 08a2a05539..f2f7858a85 100644
--- a/services/auth/oauth2.go
+++ b/services/auth/oauth2.go
@@ -14,6 +14,7 @@ import (
 	auth_model "code.gitea.io/gitea/models/auth"
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/timeutil"
 	"code.gitea.io/gitea/modules/web/middleware"
 	"code.gitea.io/gitea/services/auth/source/oauth2"
@@ -62,14 +63,19 @@ func (o *OAuth2) Name() string {
 // representing whether the token exists or not
 func parseToken(req *http.Request) (string, bool) {
 	_ = req.ParseForm()
-	// Check token.
-	if token := req.Form.Get("token"); token != "" {
-		return token, true
-	}
-	// Check access token.
-	if token := req.Form.Get("access_token"); token != "" {
-		return token, true
+	if !setting.DisableQueryAuthToken {
+		// Check token.
+		if token := req.Form.Get("token"); token != "" {
+			return token, true
+		}
+		// Check access token.
+		if token := req.Form.Get("access_token"); token != "" {
+			return token, true
+		}
+	} else if req.Form.Get("token") != "" || req.Form.Get("access_token") != "" {
+		log.Warn("API token sent in query string but DISABLE_QUERY_AUTH_TOKEN=true")
 	}
+
 	// check header token
 	if auHead := req.Header.Get("Authorization"); auHead != "" {
 		auths := strings.Fields(auHead)