From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 29205C6FA9D for ; Wed, 1 Mar 2023 18:13:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230073AbjCASNQ (ORCPT ); Wed, 1 Mar 2023 13:13:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48264 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230090AbjCASNP (ORCPT ); Wed, 1 Mar 2023 13:13:15 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B1BCE1BD5 for ; Wed, 1 Mar 2023 10:13:14 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 5F012B810C3 for ; Wed, 1 Mar 2023 18:13:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CE3C3C433EF; Wed, 1 Mar 2023 18:13:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1677694392; bh=PM7yIo6WWB961FSKIHXPIaFJQdskuFJ+i7dppETSpr4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=usJln/tkFuXKslAHVZvsF3BUEV4vI/orRc5txGmdkHbNulo1RSNvb0vggtjNgwHwG b6lhmUlQ1RCrPUNPRF8ifK1QP4/AHu7I4csfGxNc5P8FdBdNKCiA/abksmx92YxCR0 CiW+9zbZUsSxjmUEfRPeFUpbwlDuCkUh7RXyGnC8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable , Prashanth K , Alan Stern Subject: [PATCH 6.1 32/42] usb: gadget: u_serial: Add null pointer check in gserial_resume Date: Wed, 1 Mar 2023 19:08:53 +0100 Message-Id: <20230301180658.507070710@linuxfoundation.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230301180657.003689969@linuxfoundation.org> References: <20230301180657.003689969@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Prashanth K commit 5ec63fdbca604568890c577753c6f66c5b3ef0b5 upstream. Consider a case where gserial_disconnect has already cleared gser->ioport. And if a wakeup interrupt triggers afterwards, gserial_resume gets called, which will lead to accessing of gser->ioport and thus causing null pointer dereference.Add a null pointer check to prevent this. Added a static spinlock to prevent gser->ioport from becoming null after the newly added check. Fixes: aba3a8d01d62 ("usb: gadget: u_serial: add suspend resume callbacks") Cc: stable Signed-off-by: Prashanth K Acked-by: Alan Stern Link: https://lore.kernel.org/r/1676309438-14922-1-git-send-email-quic_prashk@quicinc.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/u_serial.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) --- a/drivers/usb/gadget/function/u_serial.c +++ b/drivers/usb/gadget/function/u_serial.c @@ -81,6 +81,9 @@ #define WRITE_BUF_SIZE 8192 /* TX only */ #define GS_CONSOLE_BUF_SIZE 8192 +/* Prevents race conditions while accessing gser->ioport */ +static DEFINE_SPINLOCK(serial_port_lock); + /* console info */ struct gs_console { struct console console; @@ -1374,8 +1377,10 @@ void gserial_disconnect(struct gserial * if (!port) return; + spin_lock_irqsave(&serial_port_lock, flags); + /* tell the TTY glue not to do I/O here any more */ - spin_lock_irqsave(&port->port_lock, flags); + spin_lock(&port->port_lock); gs_console_disconnect(port); @@ -1390,7 +1395,8 @@ void gserial_disconnect(struct gserial * tty_hangup(port->port.tty); } port->suspended = false; - spin_unlock_irqrestore(&port->port_lock, flags); + spin_unlock(&port->port_lock); + spin_unlock_irqrestore(&serial_port_lock, flags); /* disable endpoints, aborting down any active I/O */ usb_ep_disable(gser->out); @@ -1424,10 +1430,19 @@ EXPORT_SYMBOL_GPL(gserial_suspend); void gserial_resume(struct gserial *gser) { - struct gs_port *port = gser->ioport; + struct gs_port *port; unsigned long flags; - spin_lock_irqsave(&port->port_lock, flags); + spin_lock_irqsave(&serial_port_lock, flags); + port = gser->ioport; + + if (!port) { + spin_unlock_irqrestore(&serial_port_lock, flags); + return; + } + + spin_lock(&port->port_lock); + spin_unlock(&serial_port_lock); port->suspended = false; if (!port->start_delayed) { spin_unlock_irqrestore(&port->port_lock, flags);