linux-kernel - [RESEND PATCH] rpmsg: char: Add mutex protection for rpmsg_eptdev

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1653104105-16779-1-git-send-email-shengjiu.wang@nxp.com>
Date:   Sat, 21 May 2022 11:35:05 +0800
From:   Shengjiu Wang <shengjiu.wang@....com>
To:     bjorn.andersson@...aro.org, mathieu.poirier@...aro.org,
        arnaud.pouliquen@...s.st.com
Cc:     linux-remoteproc@...r.kernel.org, linux-kernel@...r.kernel.org,
        shengjiu.wang@...il.com
Subject: [RESEND PATCH] rpmsg: char: Add mutex protection for rpmsg_eptdev_open()

There is no mutex protection for rpmsg_eptdev_open(),
especially for eptdev->ept read and write operation.
It may cause issues when multiple instances call
rpmsg_eptdev_open() in parallel,the return state
may be success or EBUGY.

Fixes: 964e8bedd5a1 ("rpmsg: char: Return an error if device already open")
Signed-off-by: Shengjiu Wang <shengjiu.wang@....com>
---
changes in resend:
- add fixes tag

 drivers/rpmsg/rpmsg_char.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
index b6183d4f62a2..4f2189111494 100644
--- a/drivers/rpmsg/rpmsg_char.c
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -120,8 +120,11 @@ static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
 	struct rpmsg_device *rpdev = eptdev->rpdev;
 	struct device *dev = &eptdev->dev;
 
-	if (eptdev->ept)
+	mutex_lock(&eptdev->ept_lock);
+	if (eptdev->ept) {
+		mutex_unlock(&eptdev->ept_lock);
 		return -EBUSY;
+	}
 
 	get_device(dev);
 
@@ -137,11 +140,13 @@ static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
 	if (!ept) {
 		dev_err(dev, "failed to open %s\n", eptdev->chinfo.name);
 		put_device(dev);
+		mutex_unlock(&eptdev->ept_lock);
 		return -EINVAL;
 	}
 
 	eptdev->ept = ept;
 	filp->private_data = eptdev;
+	mutex_unlock(&eptdev->ept_lock);
 
 	return 0;
 }
-- 
2.17.1