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 X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 688FCC433DB for ; Mon, 11 Jan 2021 13:11:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 373F822BED for ; Mon, 11 Jan 2021 13:11:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731342AbhAKNLL (ORCPT ); Mon, 11 Jan 2021 08:11:11 -0500 Received: from mail.kernel.org ([198.145.29.99]:57332 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731135AbhAKNKL (ORCPT ); Mon, 11 Jan 2021 08:10:11 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 658F821534; Mon, 11 Jan 2021 13:09:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1610370570; bh=JBQRMPwzIFk3BqsNYbbGrUdQvze5NXP34K6QtpsmpPY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PLKmuOLkxHE5HIrz+dvfsGzbEdZX38Y0j9PURJO47+pafEB18gzfCSV9AnJgvYPAm 4aR/KxaFuhdOQT4CE/0EnLnG+M98oyhiGmnwn3yx+EA8qsj6pmwIvLwC/9yYPVaacj XhAl9GqgiFpgMiAx13RC68rx/FERT75UN4Uahc/o= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eddie Hung , Macpaul Lin , Peter Chen Subject: [PATCH 4.19 64/77] usb: gadget: configfs: Fix use-after-free issue with udc_name Date: Mon, 11 Jan 2021 14:02:13 +0100 Message-Id: <20210111130039.487052785@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210111130036.414620026@linuxfoundation.org> References: <20210111130036.414620026@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eddie Hung commit 64e6bbfff52db4bf6785fab9cffab850b2de6870 upstream. There is a use-after-free issue, if access udc_name in function gadget_dev_desc_UDC_store after another context free udc_name in function unregister_gadget. Context 1: gadget_dev_desc_UDC_store()->unregister_gadget()-> free udc_name->set udc_name to NULL Context 2: gadget_dev_desc_UDC_show()-> access udc_name Call trace: dump_backtrace+0x0/0x340 show_stack+0x14/0x1c dump_stack+0xe4/0x134 print_address_description+0x78/0x478 __kasan_report+0x270/0x2ec kasan_report+0x10/0x18 __asan_report_load1_noabort+0x18/0x20 string+0xf4/0x138 vsnprintf+0x428/0x14d0 sprintf+0xe4/0x12c gadget_dev_desc_UDC_show+0x54/0x64 configfs_read_file+0x210/0x3a0 __vfs_read+0xf0/0x49c vfs_read+0x130/0x2b4 SyS_read+0x114/0x208 el0_svc_naked+0x34/0x38 Add mutex_lock to protect this kind of scenario. Signed-off-by: Eddie Hung Signed-off-by: Macpaul Lin Reviewed-by: Peter Chen Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/1609239215-21819-1-git-send-email-macpaul.lin@mediatek.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/configfs.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) --- a/drivers/usb/gadget/configfs.c +++ b/drivers/usb/gadget/configfs.c @@ -233,9 +233,16 @@ static ssize_t gadget_dev_desc_bcdUSB_st static ssize_t gadget_dev_desc_UDC_show(struct config_item *item, char *page) { - char *udc_name = to_gadget_info(item)->composite.gadget_driver.udc_name; + struct gadget_info *gi = to_gadget_info(item); + char *udc_name; + int ret; - return sprintf(page, "%s\n", udc_name ?: ""); + mutex_lock(&gi->lock); + udc_name = gi->composite.gadget_driver.udc_name; + ret = sprintf(page, "%s\n", udc_name ?: ""); + mutex_unlock(&gi->lock); + + return ret; } static int unregister_gadget(struct gadget_info *gi)