From patchwork Wed Jan 10 09:55:32 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Uttkarsh Aggarwal X-Patchwork-Id: 762665 Received: from mx0b-0031df01.pphosted.com (mx0b-0031df01.pphosted.com [205.220.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 704AC3EA9E; Wed, 10 Jan 2024 09:56:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=quicinc.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=quicinc.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=quicinc.com header.i=@quicinc.com header.b="RA0XWxP/" Received: from pps.filterd (m0279870.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.24/8.17.1.24) with ESMTP id 40A8ctMN016855; Wed, 10 Jan 2024 09:56:34 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h= from:to:cc:subject:date:message-id:mime-version:content-type; s= qcppdkim1; bh=Js4kw6Z7/PgHtkYTNH23saebQTFsZ2uq7LYKYHCHAV4=; b=RA 0XWxP/ZGS7IEeihqTnztDTaR8XcfsYXzw0AhpYWZhlTwmNYEkX6j39VzCPyw3oBx GAY8d+ZotwSeNSLywkVXACq+wTUgDX/DCxel1B9QZZQERGxeZB1L7idChP0t/lh1 1RHcbQGuPd9TUb5qPno0721ofmEyzOmuUkHV6nP61pvMfs3n6HCYOM3EXK3/zFGg U0nQbvUCqHiPmlAolLQNq/ahoS1y+xdA66ysjerC55al4847GUfb7vjPkTIdtPZ1 tb7A+a2bdXC26bUEnDIJ11aSteQWtFhz7VO0xXffUuh4oQ/muDXBdj+ic3bw+LCI p0F+lLmjEH5/P3ubCquw== Received: from nasanppmta01.qualcomm.com (i-global254.qualcomm.com [199.106.103.254]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3vhkem0p4p-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 10 Jan 2024 09:56:33 +0000 (GMT) Received: from nasanex01a.na.qualcomm.com (nasanex01a.na.qualcomm.com [10.52.223.231]) by NASANPPMTA01.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 40A9uWNk031376 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 10 Jan 2024 09:56:32 GMT Received: from hu-uaggarwa-hyd.qualcomm.com (10.80.80.8) by nasanex01a.na.qualcomm.com (10.52.223.231) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.40; Wed, 10 Jan 2024 01:56:29 -0800 From: Uttkarsh Aggarwal To: Thinh Nguyen , Greg Kroah-Hartman CC: , , "Uttkarsh Aggarwal" Subject: [RFC PATCH] usb: dwc3: gadget: Fix NULL pointer dereference in dwc3_gadget_suspend Date: Wed, 10 Jan 2024 15:25:32 +0530 Message-ID: <20240110095532.4776-1-quic_uaggarwa@quicinc.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: nasanex01a.na.qualcomm.com (10.52.223.231) To nasanex01a.na.qualcomm.com (10.52.223.231) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-ORIG-GUID: mbs42UuGAXrU9ZJOx4Rvp_0Hob1r80-a X-Proofpoint-GUID: mbs42UuGAXrU9ZJOx4Rvp_0Hob1r80-a X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.997,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-12-09_01,2023-12-07_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 mlxscore=0 mlxlogscore=471 impostorscore=0 phishscore=0 bulkscore=1 suspectscore=0 lowpriorityscore=1 spamscore=0 priorityscore=1501 adultscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2311290000 definitions=main-2401100081 In current scenario if Plug-out and Plug-In performed continuously there could be a chance while checking for dwc->gadget_driver in dwc3_gadget_suspend, a NULL pointer dereference may occur. Call Stack: CPU1: CPU2: gadget_unbind_driver dwc3_suspend_common dw3_gadget_stop dwc3_gadget_suspend dwc3_disconnect_gadget CPU1 basically clears the variable and CPU2 checks the variable. Consider CPU1 is running and right before gadget_driver is cleared and in parallel CPU2 executes dwc3_gadget_suspend where it finds dwc->gadget_driver which is not NULL and resumes execution and then CPU1 completes execution. CPU2 executes dwc3_disconnect_gadget where it checks dwc->gadget_driver is already NULL because of which the NULL pointer deference occur. To prevent this, moving NULL pointer check inside of spin_lock. Signed-off-by: Uttkarsh Aggarwal --- drivers/usb/dwc3/gadget.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 019368f8e9c4..564976b3e2b9 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -4709,15 +4709,13 @@ int dwc3_gadget_suspend(struct dwc3 *dwc) unsigned long flags; int ret; - if (!dwc->gadget_driver) - return 0; - ret = dwc3_gadget_soft_disconnect(dwc); if (ret) goto err; spin_lock_irqsave(&dwc->lock, flags); - dwc3_disconnect_gadget(dwc); + if (dwc->gadget_driver) + dwc3_disconnect_gadget(dwc); spin_unlock_irqrestore(&dwc->lock, flags); return 0;