fix rare panic when local index collision happens (#1191)

wadey · web-flow · commit f5f6c269ac70 · 2024-08-07T11:53:32.000-04:00
A local index collision happens when two tunnels attempt to use the same
random int32 index ID. This is a rare chance, and we have code to deal
with it, but we have a panic because we return the wrong thing in this
case. This change should fix the panic.
diff --git a/handshake_manager.go b/handshake_manager.go
@@ -488,7 +488,7 @@ func (c *HandshakeManager) CheckAndComplete(hostinfo *HostInfo, handshakePacket
 	existingPendingIndex, found := c.indexes[hostinfo.localIndexId]
 	if found && existingPendingIndex.hostinfo != hostinfo {
 		// We have a collision, but for a different hostinfo
-		return existingIndex, ErrLocalIndexCollision
+		return existingPendingIndex.hostinfo, ErrLocalIndexCollision
 	}
 
 	existingRemoteIndex, found := c.mainHostMap.RemoteIndexes[hostinfo.remoteIndexId]

Original file line number	Diff line number	Diff line change
`@@ -488,7 +488,7 @@ func (c HandshakeManager) CheckAndComplete(hostinfo HostInfo, handshakePacket`
`488`	`488`	`existingPendingIndex, found := c.indexes[hostinfo.localIndexId]`
`489`	`489`	`if found && existingPendingIndex.hostinfo != hostinfo {`
`490`	`490`	`// We have a collision, but for a different hostinfo`
`491`		`- return existingIndex, ErrLocalIndexCollision`
	`491`	`+ return existingPendingIndex.hostinfo, ErrLocalIndexCollision`
`492`	`492`	`}`
`493`	`493`
`494`	`494`	`existingRemoteIndex, found := c.mainHostMap.RemoteIndexes[hostinfo.remoteIndexId]`