fileserver: Fix handling of symlink sizes in directory listings (#4415)

modules/caddyhttp/fileserver/browse.go

@@ -141,12 +141,7 @@ func (fsrv *FileServer) loadDirectoryContents(dir *os.File, root, urlPath string
 	// user can presumably browse "up" to parent folder if path is longer than "/"
 	canGoUp := len(urlPath) > 1
 
-	l, err := fsrv.directoryListing(files, canGoUp, root, urlPath, repl)
-	if err != nil {
-		return browseTemplateContext{}, err
-	}
-
-	return l, nil
+	return fsrv.directoryListing(files, canGoUp, root, urlPath, repl), nil
 }
 
 // browseApplyQueryParams applies query parameters to the listing.

modules/caddyhttp/fileserver/browsetplcontext.go

@@ -24,10 +24,11 @@ import (
 	"time"
 
 	"github.com/caddyserver/caddy/v2"
+	"github.com/caddyserver/caddy/v2/modules/caddyhttp"
 	"github.com/dustin/go-humanize"
 )
 
-func (fsrv *FileServer) directoryListing(files []os.FileInfo, canGoUp bool, root, urlPath string, repl *caddy.Replacer) (browseTemplateContext, error) {
+func (fsrv *FileServer) directoryListing(files []os.FileInfo, canGoUp bool, root, urlPath string, repl *caddy.Replacer) browseTemplateContext {
 	filesToHide := fsrv.transformHidePaths(repl)
 
 	var dirCount, fileCount int
@@ -52,14 +53,18 @@ func (fsrv *FileServer) directoryListing(files []os.FileInfo, canGoUp bool, root
 			fileCount++
 		}
 
-		fileIsSymlink := isSymlink(f)
 		size := f.Size()
+		fileIsSymlink := isSymlink(f)
 		if fileIsSymlink {
-			info, err := os.Stat(name)
-			if err != nil {
-				return browseTemplateContext{}, err
+			path := caddyhttp.SanitizedPathJoin(root, path.Join(urlPath, f.Name()))
+			fileInfo, err := os.Stat(path)
+			if err == nil {
+				size = fileInfo.Size()
 			}
-			size = info.Size()
+			// An error most likely means the symlink target doesn't exist,
+			// which isn't entirely unusual and shouldn't fail the listing.
+			// In this case, just use the size of the symlink itself, which
+			// was already set above.
 		}
 
 		fileInfos = append(fileInfos, fileInfo{
@@ -80,7 +85,7 @@ func (fsrv *FileServer) directoryListing(files []os.FileInfo, canGoUp bool, root
 		Items:    fileInfos,
 		NumDirs:  dirCount,
 		NumFiles: fileCount,
-	}, nil
+	}
 }
 
 // browseTemplateContext provides the template context for directory listings.