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Fri, 15 Dec 2023 13:41:37 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 05:41:34 -0800 From: Zijun Hu To: , , , , , , CC: , , Subject: [PATCH v2] tty: Add comments for tty-ldisc module loading logic Date: Fri, 15 Dec 2023 21:41:30 +0800 Message-ID: <1702647690-6787-1-git-send-email-quic_zijuhu@quicinc.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1702640236-22824-1-git-send-email-quic_zijuhu@quicinc.com> References: <1702640236-22824-1-git-send-email-quic_zijuhu@quicinc.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain 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: 7dD9jupRyBhKhkRsDBa3w_rjy5WQsO-X X-Proofpoint-GUID: 7dD9jupRyBhKhkRsDBa3w_rjy5WQsO-X 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 phishscore=0 malwarescore=0 priorityscore=1501 impostorscore=0 spamscore=0 mlxlogscore=999 clxscore=1011 lowpriorityscore=0 bulkscore=0 suspectscore=0 adultscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2311290000 definitions=main-2312150092 Current tty-ldisc module loading logic within tty_ldisc_get() is prone to mislead beginner that the module is able to be loaded by a user without capability CAP_SYS_MODULE, add comments to make the logic easy to undertand. Signed-off-by: Zijun Hu --- Changes in v2: - Remove condition checking changes drivers/tty/tty_ldisc.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c index 3f68e213df1f..34526ffaccbc 100644 --- a/drivers/tty/tty_ldisc.c +++ b/drivers/tty/tty_ldisc.c @@ -150,6 +150,10 @@ static struct tty_ldisc *tty_ldisc_get(struct tty_struct *tty, int disc) */ ldops = get_ldops(disc); if (IS_ERR(ldops)) { + /* + * Always request tty-ldisc module regardless of user's + * CAP_SYS_MODULE if autoload is enabled. + */ if (!capable(CAP_SYS_MODULE) && !tty_ldisc_autoload) return ERR_PTR(-EPERM); request_module("tty-ldisc-%d", disc); -- The Qualcomm Innovation Center