From patchwork Fri Dec 15 08:28:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: quic_zijuhu X-Patchwork-Id: 755384 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 5A21413AF6 for ; Fri, 15 Dec 2023 08:29:13 +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="mG9mf3hD" 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 3BF4j8ch030663; Fri, 15 Dec 2023 08:29:09 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=Rtq7pLXxCJVqYoA9YX3KTEKSSu5SyO6189Mebf3INIw=; b=mG 9mf3hDD2WartwAMNlBOujxExwztU0gBEd/V/6/aSK9qeeZyebYlNVv+Yq2AP3zjZ VUTcgGhkPOS5zg4TjS8QjGRegRCtBQ4k9oYs7xw0Kefm8KRsnCVznyoYrqSramAr HnIlZ6/+S1HKRXDz3nj58QNHsotmAVetPSI5hSOK0eEAZRhKMwmVkXW92L0GHZpl /7uQMCIxGQXXXW4iJyEXgdOAkvpY+8AZJ88XopskZpWMc6nJIfu6+h+vNndiNH0R bD7HjlZaqKBk37EkVuHQ/jZuH2wja1IepmFnntDpbV+ReJkky/vxzvGltWFUe1Mj fDWKwc/P+hdLDSLGX/aw== Received: from nasanppmta05.qualcomm.com (i-global254.qualcomm.com [199.106.103.254]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3v0a37hh2a-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 15 Dec 2023 08:29:09 +0000 (GMT) Received: from nasanex01a.na.qualcomm.com (nasanex01a.na.qualcomm.com [10.52.223.231]) by NASANPPMTA05.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 3BF8T8xk003234 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 15 Dec 2023 08:29:08 GMT Received: from zijuhu-gv.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; Fri, 15 Dec 2023 00:29:04 -0800 From: Zijun Hu To: , CC: , Subject: [PATCH v1] tty: Fix a security issue related to tty-ldisc module loading Date: Fri, 15 Dec 2023 16:28:53 +0800 Message-ID: <1702628933-6070-1-git-send-email-quic_zijuhu@quicinc.com> X-Mailer: git-send-email 2.7.4 Precedence: bulk X-Mailing-List: linux-serial@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-GUID: TTqsO6pgmQIeuW8KEuoWOVoQTJ12Bpmw X-Proofpoint-ORIG-GUID: TTqsO6pgmQIeuW8KEuoWOVoQTJ12Bpmw 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 mlxscore=0 suspectscore=0 malwarescore=0 clxscore=1011 bulkscore=0 adultscore=0 mlxlogscore=999 spamscore=0 phishscore=0 impostorscore=0 lowpriorityscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2311290000 definitions=main-2312150052 Function tty_ldisc_get() has a simple logical error and may cause tty-ldisc module to be loaded by a user without CAP_SYS_MODULE, this security issue is fixed by correcting the logical error. Signed-off-by: Zijun Hu --- drivers/tty/tty_ldisc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c index 3f68e213df1f..b490c0adf00f 100644 --- a/drivers/tty/tty_ldisc.c +++ b/drivers/tty/tty_ldisc.c @@ -150,7 +150,7 @@ static struct tty_ldisc *tty_ldisc_get(struct tty_struct *tty, int disc) */ ldops = get_ldops(disc); if (IS_ERR(ldops)) { - if (!capable(CAP_SYS_MODULE) && !tty_ldisc_autoload) + if (!capable(CAP_SYS_MODULE) || !tty_ldisc_autoload) return ERR_PTR(-EPERM); request_module("tty-ldisc-%d", disc); ldops = get_ldops(disc);