From f9684b73e95a0f52f0049384ea34c2953b3c9200 Mon Sep 17 00:00:00 2001
From: abakum <koka.abakum@gmail.com>
Date: Thu, 21 May 2026 17:35:29 +0300
Subject: [PATCH] feat: skip file info transfer for /dev/null placeholder

When the sender has exactly one file and it is /dev/null, skip the
file info transfer step. This enables reusing croc's secure tunnel
(PAKE + encryption + authentication) for WebDAV or other apps
without sending real files through the croc protocol.
---
 src/croc/croc.go | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/croc/croc.go b/src/croc/croc.go
index e9cba8e39..8f518fcdb 100644
--- a/src/croc/croc.go
+++ b/src/croc/croc.go
@@ -1662,6 +1662,15 @@ func (c *Client) processMessage(payload []byte) (done bool, err error) {
 
 func (c *Client) updateIfSenderChannelSecured() (err error) {
 	if c.Options.IsSender && c.Step1ChannelSecured && !c.Step2FileInfoTransferred {
+
+		if len(c.FilesToTransfer) == 1 &&
+			c.FilesToTransfer[0].Name == filepath.Base(os.DevNull) &&
+			c.FilesToTransfer[0].FolderSource == filepath.Dir(os.DevNull) {
+			log.Debug(os.DevNull)
+			c.Step2FileInfoTransferred = true
+			return
+		}
+
 		var b []byte
 		machID, _ := machineid.ID()
 		b, err = json.Marshal(SenderInfo{