OIDC: add support for custom fields

These fields can be used in the pre-login hook to implement custom
logics

Fixes #787

Signed-off-by: Nicola Murino <nicola.murino@gmail.com>

vfs/osfs.go

@@ -3,6 +3,7 @@ package vfs
 import (
 	"fmt"
 	"io"
+	"io/fs"
 	"net/http"
 	"os"
 	"path"
@@ -170,12 +171,20 @@ func (*OsFs) ReadDir(dirname string) ([]os.FileInfo, error) {
 	if err != nil {
 		return nil, err
 	}
-	list, err := f.Readdir(-1)
+	entries, err := f.ReadDir(-1)
 	f.Close()
 	if err != nil {
 		return nil, err
 	}
-	return list, nil
+	result := make([]fs.FileInfo, len(entries))
+	for idx, entry := range entries {
+		info, err := entry.Info()
+		if err != nil {
+			return nil, err
+		}
+		result[idx] = info
+	}
+	return result, nil
 }
 
 // IsUploadResumeSupported returns true if resuming uploads is supported