1 files changed, 107 insertions, 0 deletions
diff --git a/services/actions/auth.go b/services/actions/auth.go
new file mode 100644
index 0000000..1ef21f6
--- /dev/null
+++ b/services/actions/auth.go
@@ -0,0 +1,107 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package actions
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+	"time"
+
+	"code.gitea.io/gitea/modules/json"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+
+	"github.com/golang-jwt/jwt/v5"
+)
+
+type actionsClaims struct {
+	jwt.RegisteredClaims
+	Scp    string `json:"scp"`
+	TaskID int64
+	RunID  int64
+	JobID  int64
+	Ac     string `json:"ac"`
+}
+
+type actionsCacheScope struct {
+	Scope      string
+	Permission actionsCachePermission
+}
+
+type actionsCachePermission int
+
+const (
+	actionsCachePermissionRead = 1 << iota
+	actionsCachePermissionWrite
+)
+
+func CreateAuthorizationToken(taskID, runID, jobID int64) (string, error) {
+	now := time.Now()
+
+	ac, err := json.Marshal(&[]actionsCacheScope{
+		{
+			Scope:      "",
+			Permission: actionsCachePermissionWrite,
+		},
+	})
+	if err != nil {
+		return "", err
+	}
+
+	claims := actionsClaims{
+		RegisteredClaims: jwt.RegisteredClaims{
+			ExpiresAt: jwt.NewNumericDate(now.Add(24 * time.Hour)),
+			NotBefore: jwt.NewNumericDate(now),
+		},
+		Scp:    fmt.Sprintf("Actions.Results:%d:%d", runID, jobID),
+		Ac:     string(ac),
+		TaskID: taskID,
+		RunID:  runID,
+		JobID:  jobID,
+	}
+	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
+
+	tokenString, err := token.SignedString(setting.GetGeneralTokenSigningSecret())
+	if err != nil {
+		return "", err
+	}
+
+	return tokenString, nil
+}
+
+func ParseAuthorizationToken(req *http.Request) (int64, error) {
+	h := req.Header.Get("Authorization")
+	if h == "" {
+		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 TokenToTaskID(parts[1])
+}
+
+// TokenToTaskID returns the TaskID associated with the provided JWT token
+func TokenToTaskID(token string) (int64, error) {
+	parsedToken, err := jwt.ParseWithClaims(token, &actionsClaims{}, func(t *jwt.Token) (any, error) {
+		if _, ok := t.Method.(*jwt.SigningMethodHMAC); !ok {
+			return nil, fmt.Errorf("unexpected signing method: %v", t.Header["alg"])
+		}
+		return setting.GetGeneralTokenSigningSecret(), nil
+	})
+	if err != nil {
+		return 0, err
+	}
+
+	c, ok := parsedToken.Claims.(*actionsClaims)
+	if !parsedToken.Valid || !ok {
+		return 0, fmt.Errorf("invalid token claim")
+	}
+
+	return c.TaskID, nil
+}