From 26a2d0b2a147162e2468696925daec038992cee8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E1=B4=9C=C9=B4=E1=B4=8B=C9=B4=E1=B4=A1=E1=B4=8F=C9=B4?=
 <u@gogs.io>
Date: Sun, 12 Apr 2020 09:18:58 +0800
Subject: [PATCH] ssh: ignore malformed "env" commands (#6094)

---
 internal/ssh/ssh.go | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/internal/ssh/ssh.go b/internal/ssh/ssh.go
index a4d41d0f6..cb9d5ed7e 100644
--- a/internal/ssh/ssh.go
+++ b/internal/ssh/ssh.go
@@ -57,11 +57,19 @@ func handleServerConn(keyID string, chans <-chan ssh.NewChannel) {
 						continue
 					}
 					args[0] = strings.TrimLeft(args[0], "\x04")
-					_, _, err := com.ExecCmdBytes("env", args[0]+"="+args[1])
+
+					// Sometimes the client could send malformed command (i.e. missing "="),
+					// see https://discuss.gogs.io/t/ssh/3106.
+					if args[0] == "" {
+						continue
+					}
+
+					_, stderr, err := com.ExecCmd("env", args[0]+"="+args[1])
 					if err != nil {
-						log.Error("env: %v", err)
+						log.Error("env: %v - %s", err, stderr)
 						return
 					}
+
 				case "exec":
 					cmdName := strings.TrimLeft(payload, "'()")
 					log.Trace("SSH: Payload: %v", cmdName)