From patchwork Fri Feb 2 06:40:38 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ekansh Gupta X-Patchwork-Id: 13542158 Received: from mx0a-0031df01.pphosted.com (mx0a-0031df01.pphosted.com [205.220.168.131]) (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 68C6547A76; Fri, 2 Feb 2024 06:41:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=205.220.168.131 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706856086; cv=none; b=CRTuxeOjrA1oHkIynJlZhRS2mufLJ3YQMcEh4Xnq9YgME7GUiBJl3++eUFxrnyHL6Df65zTtV50oZ9Uz+yvaYXXxZpueSVtyrq7ZLHfvNCovIDT1L3QLd9gMkVpo4vLlZB32z7tfQN6JyPa8gELSGZJz723geO+EZAR5kSbB9xI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706856086; c=relaxed/simple; bh=qbNEGZz2C4Gx3HMPisN75TK8yz+GYjwi6ez/CMvVt6o=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=mDHiDsUhVpF6cBTfHm7ZaurNfdVWXhE+M78QSdZV16AOJk4lMysLiHZ3XrLQBYSJ2pmdex7sV7l4sj3ALdJjpNTfTkO8e/Yx1zvZ3konH+x52pyBaQXmDK1rxuKXUZwqo2+eHps0OUJykqk1jcShyBNi+eE9OBVcEECtTcFXVMM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=quicinc.com; spf=pass smtp.mailfrom=quicinc.com; dkim=pass (2048-bit key) header.d=quicinc.com header.i=@quicinc.com header.b=YWCb/Qxe; arc=none smtp.client-ip=205.220.168.131 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="YWCb/Qxe" Received: from pps.filterd (m0279867.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.24/8.17.1.24) with ESMTP id 4126A0IY017772; Fri, 2 Feb 2024 06:41:22 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h= from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-type; s=qcppdkim1; bh=LCXm5lUyxmruJ09/Ia5z NnoeixYPjyKFDjc2aPuwBcM=; b=YWCb/QxeUO512bf1XYcGTvzSUUY8dVYr+uEW hJALsDgpmO5pdjsQZlf+ipIiXg/8jCUdNQANSX/bbMu2UEVaEKUuIeNs1PO+u8ff MN+hflJj8dZAWgBQ1kn0dho+8o0YXjgCTTpPUSsxHHCp2OfAlVOxCDMa12ubXESX 7fUiidjoF8U3ODsjsDgc69kzZmkzv5LuuwjKsx8bs4D6xTng0oE2GdaaLUGtslZt fWOra5AgQciKjipfgwjQySESr+cxqPONX0JLclxcyh1LBYx4S5evTWScP6jqnr4v BJGqW2kfmP552X+Q+FcGaDoLX6WXzeobCpoGex1I4xozbPVfjA== Received: from nalasppmta04.qualcomm.com (Global_NAT1.qualcomm.com [129.46.96.20]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3w0ptxgnpg-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 02 Feb 2024 06:41:22 +0000 (GMT) Received: from nalasex01b.na.qualcomm.com (nalasex01b.na.qualcomm.com [10.47.209.197]) by NALASPPMTA04.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 4126fLfE002710 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 2 Feb 2024 06:41:21 GMT Received: from hu-ekangupt-hyd.qualcomm.com (10.80.80.8) by nalasex01b.na.qualcomm.com (10.47.209.197) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.40; Thu, 1 Feb 2024 22:41:19 -0800 From: Ekansh Gupta To: , CC: , Subject: [PATCH v1 15/16] misc: fastrpc: Restrict untrusted apk to spawn privileged PD Date: Fri, 2 Feb 2024 12:10:38 +0530 Message-ID: <20240202064039.15505-16-quic_ekangupt@quicinc.com> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20240202064039.15505-1-quic_ekangupt@quicinc.com> References: <20240202064039.15505-1-quic_ekangupt@quicinc.com> Precedence: bulk X-Mailing-List: linux-arm-msm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: nasanex01a.na.qualcomm.com (10.52.223.231) To nalasex01b.na.qualcomm.com (10.47.209.197) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-ORIG-GUID: -YarlE4HGTE6R_7E4QvVLmPChXBLSlkc X-Proofpoint-GUID: -YarlE4HGTE6R_7E4QvVLmPChXBLSlkc X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.1011,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2024-02-01_10,2024-01-31_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 bulkscore=0 adultscore=0 impostorscore=0 priorityscore=1501 malwarescore=0 spamscore=0 suspectscore=0 mlxlogscore=581 mlxscore=0 phishscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2401310000 definitions=main-2402020047 Untrusted application can attach to guestOS and staticPD if it can make root PD, sensors PD or audio PD attach request. This is a potential security issue as the untrusted application can crash rootPD or staticPD. Restrict attach to guestOS or staticPD request if request is being made using non-secure device node. Also for untrusted dynamic processes, DSP HAL process opens the device node on behalf of the application. Add a check to restrict such untrusted applications from offloading to signed PD. Signed-off-by: Ekansh Gupta --- drivers/misc/fastrpc.c | 35 +++++++++++++++++++++++++++++------ 1 file changed, 29 insertions(+), 6 deletions(-) diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c index 0308f717456f..4aa4e36bebc3 100644 --- a/drivers/misc/fastrpc.c +++ b/drivers/misc/fastrpc.c @@ -471,6 +471,7 @@ struct fastrpc_user { bool sharedcb; /* If set, threads will poll for DSP response instead of glink wait */ bool poll_mode; + bool untrusted_process; char *servloc_name; /* Lock for lists */ spinlock_t lock; @@ -1722,20 +1723,24 @@ static int fastrpc_internal_invoke(struct fastrpc_user *fl, u32 kernel, static bool is_session_rejected(struct fastrpc_user *fl, bool unsigned_pd_request) { - /* Check if the device node is non-secure and channel is secure*/ + /* Check if the device node is non-secure and channel is secure */ if (!fl->is_secure_dev && fl->cctx->secure) { /* * Allow untrusted applications to offload only to Unsigned PD when * channel is configured as secure and block untrusted apps on channel * that does not support unsigned PD offload */ - if (!fl->cctx->unsigned_support || !unsigned_pd_request) { - dev_err(&fl->cctx->rpdev->dev, "Error: Untrusted application trying to offload to signed PD"); - return true; - } + if (!fl->cctx->unsigned_support || !unsigned_pd_request) + goto reject_session; } + /* Check if untrusted process is trying to offload to signed PD */ + if (fl->untrusted_process && !unsigned_pd_request) + goto reject_session; return false; +reject_session: + dev_err(&fl->cctx->rpdev->dev, "Error: Untrusted application trying to offload to signed PD"); + return true; } static int fastrpc_mmap_remove_ssr(struct fastrpc_channel_ctx *cctx) @@ -1822,6 +1827,11 @@ static int fastrpc_init_create_static_process(struct fastrpc_user *fl, u32 pageslen; } inbuf; + if (!fl->is_secure_dev) { + dev_err(&fl->cctx->rpdev->dev, "untrusted app trying to attach to privileged DSP PD\n"); + return -EACCES; + } + args = kcalloc(FASTRPC_CREATE_STATIC_PROCESS_NARGS, sizeof(*args), GFP_KERNEL); if (!args) return -ENOMEM; @@ -1981,11 +1991,19 @@ static int fastrpc_init_create_process(struct fastrpc_user *fl, goto err; } + /* + * Third-party apps don't have permission to open the fastrpc device, so + * it is opened on their behalf by DSP HAL. This is detected by + * comparing current PID with the one stored during device open. + */ + if (current->tgid != fl->tgid) + fl->untrusted_process = true; + if (init.attrs & FASTRPC_MODE_UNSIGNED_MODULE) fl->is_unsigned_pd = true; if (is_session_rejected(fl, fl->is_unsigned_pd)) { - err = -ECONNREFUSED; + err = -EACCES; goto err; } @@ -2244,6 +2262,11 @@ static int fastrpc_init_attach(struct fastrpc_user *fl, int pd) struct fastrpc_enhanced_invoke ioctl; int tgid = fl->tgid; + if (!fl->is_secure_dev) { + dev_err(&fl->cctx->rpdev->dev, "untrusted app trying to attach to privileged DSP PD\n"); + return -EACCES; + } + fl->sctx = fastrpc_session_alloc(fl->cctx, fl->sharedcb); if (!fl->sctx) return -EBUSY;