From patchwork Sat Jul 18 02:45:03 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Macpaul Lin X-Patchwork-Id: 11671539 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6FCD513A4 for ; Sat, 18 Jul 2020 02:45:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4D2002067D for ; Sat, 18 Jul 2020 02:45:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=mediatek.com header.i=@mediatek.com header.b="h6JqILvm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728097AbgGRCpR (ORCPT ); Fri, 17 Jul 2020 22:45:17 -0400 Received: from mailgw02.mediatek.com ([210.61.82.184]:56016 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726742AbgGRCpR (ORCPT ); Fri, 17 Jul 2020 22:45:17 -0400 X-UUID: f2b1f400fbb7493d8e2f8c85de7bd2f1-20200718 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mediatek.com; s=dk; h=Content-Transfer-Encoding:Content-Type:MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:CC:To:From; bh=JJ5o+WFe3CVKnlVdykIeEjsdjGfkUl9MSJCZgz3eF2c=; b=h6JqILvmrVsxfhR1S5A3n9e/L1cwpXlmhF1eG/kO4ynP2Bsx/fIlOHDXdBLAQkOw2EwU0vFwTMHCjmRSr7EwZo3tuVoF+zFb+S9B95qrIj+wFoko8Kk6EBa+XonE2kfVGf852Uz/da6Cp377oyfkC6c+VdPZR4b4UaU0bJoA4OU=; X-UUID: f2b1f400fbb7493d8e2f8c85de7bd2f1-20200718 Received: from mtkcas06.mediatek.inc [(172.21.101.30)] by mailgw02.mediatek.com (envelope-from ) (Cellopoint E-mail Firewall v4.1.10 Build 0809 with TLS) with ESMTP id 1127202755; Sat, 18 Jul 2020 10:45:12 +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; Sat, 18 Jul 2020 10:45:09 +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; Sat, 18 Jul 2020 10:45:10 +0800 From: Macpaul Lin To: Felipe Balbi , Greg Kroah-Hartman , Matthias Brugger , , , , CC: Mediatek WSD Upstream , Macpaul Lin , Macpaul Lin , Eddie Hung , Subject: [PATCH v2] usb: gadget: configfs: Fix use-after-free issue with udc_name Date: Sat, 18 Jul 2020 10:45:03 +0800 Message-ID: <1595040303-23046-1-git-send-email-macpaul.lin@mediatek.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1594881666-8843-1-git-send-email-macpaul.lin@mediatek.com> References: <1594881666-8843-1-git-send-email-macpaul.lin@mediatek.com> MIME-Version: 1.0 X-TM-SNTS-SMTP: 7A91C36DAFF4860455E96955268D0533348A3C2AFE1C668A6C271346DB2534C92000:8 X-MTK: N Sender: linux-usb-owner@vger.kernel.org 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 9dc06a4e1b30..21110b2865b9 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)