refactor(webdav): Use ResolvePath instead of JoinPath

- Changed the path concatenation method between `reqPath` and `src` and `dst` to use `ResolvePath`
- Updated the implementation of path handling in multiple functions
- Improved the consistency and reliability of path resolution

Author: okatu-loli

server/webdav.go

@@ -113,7 +113,7 @@ func WebDAVAuth(c *gin.Context) {
 		reqPath = "/"
 	}
 	reqPath, _ = url.PathUnescape(reqPath)
-	reqPath, err = user.JoinPath(reqPath)
+	reqPath, err = webdav.ResolvePath(user, reqPath)
 	if err != nil {
 		c.Status(http.StatusForbidden)
 		c.Abort()

server/webdav/path.go

@@ -0,0 +1,22 @@
+package webdav
+
+import (
+	"path"
+	"strings"
+
+	"github.com/alist-org/alist/v3/internal/model"
+	"github.com/alist-org/alist/v3/pkg/utils"
+)
+
+// ResolvePath normalizes the provided raw path and resolves it against the user's base path
+// before delegating to the user-aware JoinPath permission checks.
+func ResolvePath(user *model.User, raw string) (string, error) {
+	cleaned := utils.FixAndCleanPath(raw)
+	basePath := utils.FixAndCleanPath(user.BasePath)
+
+	if cleaned != "/" && basePath != "/" && !utils.IsSubPath(basePath, cleaned) {
+		cleaned = path.Join(basePath, strings.TrimPrefix(cleaned, "/"))
+	}
+
+	return user.JoinPath(cleaned)
+}

server/webdav/webdav.go

@@ -194,7 +194,7 @@ func (h *Handler) handleOptions(w http.ResponseWriter, r *http.Request) (status
 	}
 	ctx := r.Context()
 	user := ctx.Value("user").(*model.User)
-	reqPath, err = user.JoinPath(reqPath)
+	reqPath, err = ResolvePath(user, reqPath)
 	if err != nil {
 		return 403, err
 	}
@@ -222,7 +222,7 @@ func (h *Handler) handleGetHeadPost(w http.ResponseWriter, r *http.Request) (sta
 	// TODO: check locks for read-only access??
 	ctx := r.Context()
 	user := ctx.Value("user").(*model.User)
-	reqPath, err = user.JoinPath(reqPath)
+	reqPath, err = ResolvePath(user, reqPath)
 	if err != nil {
 		return http.StatusForbidden, err
 	}
@@ -282,7 +282,7 @@ func (h *Handler) handleDelete(w http.ResponseWriter, r *http.Request) (status i
 
 	ctx := r.Context()
 	user := ctx.Value("user").(*model.User)
-	reqPath, err = user.JoinPath(reqPath)
+	reqPath, err = ResolvePath(user, reqPath)
 	if err != nil {
 		return 403, err
 	}
@@ -321,7 +321,7 @@ func (h *Handler) handlePut(w http.ResponseWriter, r *http.Request) (status int,
 	// comments in http.checkEtag.
 	ctx := r.Context()
 	user := ctx.Value("user").(*model.User)
-	reqPath, err = user.JoinPath(reqPath)
+	reqPath, err = ResolvePath(user, reqPath)
 	if err != nil {
 		return http.StatusForbidden, err
 	}
@@ -375,7 +375,7 @@ func (h *Handler) handleMkcol(w http.ResponseWriter, r *http.Request) (status in
 
 	ctx := r.Context()
 	user := ctx.Value("user").(*model.User)
-	reqPath, err = user.JoinPath(reqPath)
+	reqPath, err = ResolvePath(user, reqPath)
 	if err != nil {
 		return 403, err
 	}
@@ -439,11 +439,11 @@ func (h *Handler) handleCopyMove(w http.ResponseWriter, r *http.Request) (status
 
 	ctx := r.Context()
 	user := ctx.Value("user").(*model.User)
-	src, err = user.JoinPath(src)
+	src, err = ResolvePath(user, src)
 	if err != nil {
 		return 403, err
 	}
-	dst, err = user.JoinPath(dst)
+	dst, err = ResolvePath(user, dst)
 	if err != nil {
 		return 403, err
 	}
@@ -540,7 +540,7 @@ func (h *Handler) handleLock(w http.ResponseWriter, r *http.Request) (retStatus
 		if err != nil {
 			return status, err
 		}
-		reqPath, err = user.JoinPath(reqPath)
+		reqPath, err = ResolvePath(user, reqPath)
 		if err != nil {
 			return 403, err
 		}
@@ -623,7 +623,7 @@ func (h *Handler) handlePropfind(w http.ResponseWriter, r *http.Request) (status
 	userAgent := r.Header.Get("User-Agent")
 	ctx = context.WithValue(ctx, "userAgent", userAgent)
 	user := ctx.Value("user").(*model.User)
-	reqPath, err = user.JoinPath(reqPath)
+	reqPath, err = ResolvePath(user, reqPath)
 	if err != nil {
 		return 403, err
 	}
@@ -801,7 +801,7 @@ func (h *Handler) handleProppatch(w http.ResponseWriter, r *http.Request) (statu
 
 	ctx := r.Context()
 	user := ctx.Value("user").(*model.User)
-	reqPath, err = user.JoinPath(reqPath)
+	reqPath, err = ResolvePath(user, reqPath)
 	if err != nil {
 		return 403, err
 	}