Make sure the other conn end not closed before using it

Author: sonertari

src/protoautossl.c

@@ -441,12 +441,6 @@ protoautossl_bev_readcb_srvdst(struct bufferevent *bev, pxy_conn_ctx_t *ctx)
 {
 	log_finest_va("ENTER, size=%zu", evbuffer_get_length(bufferevent_get_input(bev)));
 
-#ifndef WITHOUT_USERAUTH
-	if (prototcp_try_send_userauth_msg(ctx->src.bev, ctx)) {
-		return;
-	}
-#endif /* !WITHOUT_USERAUTH */
-
 	// @todo We should validate the response from the server to protect the client,
 	// as we do with the smtp protocol, @see protosmtp_bev_readcb_srvdst()
 
@@ -455,6 +449,12 @@ protoautossl_bev_readcb_srvdst(struct bufferevent *bev, pxy_conn_ctx_t *ctx)
 		return;
 	}
 
+#ifndef WITHOUT_USERAUTH
+	if (prototcp_try_send_userauth_msg(ctx->src.bev, ctx)) {
+		return;
+	}
+#endif /* !WITHOUT_USERAUTH */
+
 	evbuffer_add_buffer(bufferevent_get_output(ctx->src.bev), bufferevent_get_input(bev));
 	ctx->protoctx->set_watermarkcb(bev, ctx, ctx->src.bev);
 }

src/protosmtp.c

@@ -182,12 +182,18 @@ protosmtp_bev_readcb_srvdst(struct bufferevent *bev, pxy_conn_ctx_t *ctx)
 {
 	log_finest_va("ENTER, size=%zu", evbuffer_get_length(bufferevent_get_input(bev)));
 
+	// TODO: Do we need to check src.bev here?
 	// Make sure src.bev exists
 	if (!ctx->src.bev) {
 		log_finest("src.bev does not exist");
 		return;
 	}
 
+	if (ctx->src.closed) {
+		ctx->protoctx->discard_inbufcb(bev);
+		return;
+	}
+
 #ifndef WITHOUT_USERAUTH
 	if (prototcp_try_send_userauth_msg(ctx->src.bev, ctx)) {
 		return;
@@ -206,11 +212,6 @@ protosmtp_bev_readcb_srvdst(struct bufferevent *bev, pxy_conn_ctx_t *ctx)
 		return;
 	}
 
-	if (ctx->src.closed) {
-		ctx->protoctx->discard_inbufcb(bev);
-		return;
-	}
-
 	evbuffer_add_buffer(outbuf, inbuf);
 	ctx->protoctx->set_watermarkcb(bev, ctx, ctx->src.bev);
 }