[SEC] Ensure propagation of API scopes for Conan and Container authentication

- The Conan and Container packages use a different type of
authentication. It first authenticates via the regular way (api tokens
or user:password, handled via `auth.Basic`) and then generates a JWT
token that is used by the package software (such as Docker) to do the
action they wanted to do. This JWT token didn't properly propagate the
API scopes that the token was generated for, and thus could lead to a
'scope escalation' within the Conan and Container packages, read
access to write access.
- Store the API scope in the JWT token, so it can be propagated on
subsequent calls that uses that JWT token.
- Integration test added.
- Resolves #5128

(cherry picked from commit 5a871f6095)

services/packages/auth.go

@@ -9,6 +9,7 @@ import (
 	"strings"
 	"time"
 
+	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"
@@ -19,9 +20,10 @@ import (
 type packageClaims struct {
 	jwt.RegisteredClaims
 	UserID int64
+	Scope  auth_model.AccessTokenScope
 }
 
-func CreateAuthorizationToken(u *user_model.User) (string, error) {
+func CreateAuthorizationToken(u *user_model.User, scope auth_model.AccessTokenScope) (string, error) {
 	now := time.Now()
 
 	claims := packageClaims{
@@ -30,6 +32,7 @@ func CreateAuthorizationToken(u *user_model.User) (string, error) {
 			NotBefore: jwt.NewNumericDate(now),
 		},
 		UserID: u.ID,
+		Scope:  scope,
 	}
 	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
 
@@ -41,16 +44,16 @@ func CreateAuthorizationToken(u *user_model.User) (string, error) {
 	return tokenString, nil
 }
 
-func ParseAuthorizationToken(req *http.Request) (int64, error) {
+func ParseAuthorizationToken(req *http.Request) (int64, auth_model.AccessTokenScope, error) {
 	h := req.Header.Get("Authorization")
 	if h == "" {
-		return 0, nil
+		return 0, "", nil
 	}
 
 	parts := strings.SplitN(h, " ", 2)
 	if len(parts) != 2 {
 		log.Error("split token failed: %s", h)
-		return 0, fmt.Errorf("split token failed")
+		return 0, "", fmt.Errorf("split token failed")
 	}
 
 	token, err := jwt.ParseWithClaims(parts[1], &packageClaims{}, func(t *jwt.Token) (any, error) {
@@ -60,13 +63,13 @@ func ParseAuthorizationToken(req *http.Request) (int64, error) {
 		return setting.GetGeneralTokenSigningSecret(), nil
 	})
 	if err != nil {
-		return 0, err
+		return 0, "", err
 	}
 
 	c, ok := token.Claims.(*packageClaims)
 	if !token.Valid || !ok {
-		return 0, fmt.Errorf("invalid token claim")
+		return 0, "", fmt.Errorf("invalid token claim")
 	}
 
-	return c.UserID, nil
+	return c.UserID, c.Scope, nil
 }