If the SSH server sends us CHANNEL_CLOSE for a channel on which we're

sitting on a pile of buffered data waiting for WINDOW_ADJUSTs, we
should throw away that buffered data, because the CHANNEL_CLOSE tells
us that we won't be receiving those WINDOW_ADJUSTs, and if we hang on
to the data and keep trying then it'll prevent ssh_channel_try_eof
from sending the CHANNEL_EOF which is a prerequisite of sending our
own CHANNEL_CLOSE.

[originally from svn r9953]

ssh.c

@@ -7093,6 +7093,15 @@ static void ssh2_msg_channel_close(Ssh ssh, struct Packet *pktin)
 	    break;
         }
 
+        /*
+         * Abandon any buffered data we still wanted to send to this
+         * channel. Receiving a CHANNEL_CLOSE is an indication that
+         * the server really wants to get on and _destroy_ this
+         * channel, and it isn't going to send us any further
+         * WINDOW_ADJUSTs to permit us to send pending stuff.
+         */
+        bufchain_clear(&c->v.v2.outbuffer);
+
         /*
          * Send outgoing EOF.
          */