[tor-commits] [snowflake/main] Fix error handling around transport.Dial.

[cohosh at torproject.org]

commit 01a96c7d95bfcc6ec5b6a770c8a56ef7da6605f4
Author: David Fifield <david at bamsoftware.com>
Date:   Mon May 24 14:36:24 2021 -0600

    Fix error handling around transport.Dial.
    
    The code checked for and displayed an error, but would then go on to
    call copyLoop on the nil Conn returned from transport.Dial. Add a return
    in that case, and put the cleanup operations in defer. Also remove an
    obsolete comment about an empty address. Obsolete because:
    https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake/-/merge_requests/31#note_2733279
---
 client/snowflake.go | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/client/snowflake.go b/client/snowflake.go
index f19afcf..bacc389 100644
--- a/client/snowflake.go
+++ b/client/snowflake.go
@@ -69,17 +69,15 @@ func socksAcceptLoop(ln *pt.SocksListener, transport *sf.Transport, shutdown cha
 
 			handler := make(chan struct{})
 			go func() {
-				// pass an empty address because the broker chooses the bridge
+				defer close(handler)
 				sconn, err := transport.Dial()
 				if err != nil {
 					log.Printf("dial error: %s", err)
+					return
 				}
+				defer sconn.Close()
 				// copy between the created Snowflake conn and the SOCKS conn
 				copyLoop(conn, sconn)
-				sconn.Close()
-				close(handler)
-				return
-
 			}()
 			select {
 			case <-shutdown: