From patchwork Tue Dec 29 10:53:35 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Macpaul Lin X-Patchwork-Id: 11992177 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 2BFF6C433E0 for ; Tue, 29 Dec 2020 10:55:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EE3EA207D1 for ; Tue, 29 Dec 2020 10:55:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726048AbgL2KzN (ORCPT ); Tue, 29 Dec 2020 05:55:13 -0500 Received: from mailgw02.mediatek.com ([210.61.82.184]:54256 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1725866AbgL2KzM (ORCPT ); Tue, 29 Dec 2020 05:55:12 -0500 X-UUID: 939ac46eb0be4dd28ecef758b110a329-20201229 X-UUID: 939ac46eb0be4dd28ecef758b110a329-20201229 Received: from mtkcas06.mediatek.inc [(172.21.101.30)] by mailgw02.mediatek.com (envelope-from ) (Cellopoint E-mail Firewall v4.1.14 Build 0819 with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 277752702; Tue, 29 Dec 2020 18:54:25 +0800 Received: from mtkcas07.mediatek.inc (172.21.101.84) by mtkmbs01n2.mediatek.inc (172.21.101.79) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 29 Dec 2020 18:54:22 +0800 Received: from mtkswgap22.mediatek.inc (172.21.77.33) by mtkcas07.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Tue, 29 Dec 2020 18:54:22 +0800 From: Macpaul Lin To: Felipe Balbi , Greg Kroah-Hartman , Matthias Brugger , , , , , Mediatek WSD Upstream , Macpaul Lin CC: Ainge Hsu , Eddie Hung , Chunfeng Yun , Macpaul Lin , Subject: [PATCH RESEND v2] usb: gadget: configfs: Fix use-after-free issue with udc_name Date: Tue, 29 Dec 2020 18:53:35 +0800 Message-ID: <1609239215-21819-1-git-send-email-macpaul.lin@mediatek.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1595040303-23046-1-git-send-email-macpaul.lin@mediatek.com> References: <1595040303-23046-1-git-send-email-macpaul.lin@mediatek.com> MIME-Version: 1.0 X-TM-SNTS-SMTP: D7599083FB75AC51A42E27F5D4110B8FDDD3B0ADAEA3DC865F0F32B8950722872000:8 X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Eddie Hung 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 --- Changes for v2: - Fix typo %s/contex/context, Thanks Peter. drivers/usb/gadget/configfs.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c index 56051bb..d9743f4 100644 --- a/drivers/usb/gadget/configfs.c +++ b/drivers/usb/gadget/configfs.c @@ -221,9 +221,16 @@ static ssize_t gadget_dev_desc_bcdUSB_store(struct config_item *item, 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; + + mutex_lock(&gi->lock); + udc_name = gi->composite.gadget_driver.udc_name; + ret = sprintf(page, "%s\n", udc_name ?: ""); + mutex_unlock(&gi->lock); - return sprintf(page, "%s\n", udc_name ?: ""); + return ret; } static int unregister_gadget(struct gadget_info *gi)