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From:   Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
To:     Bjorn Andersson <bjorn.andersson@linaro.org>,
        Ohad Ben-Cohen <ohad@wizery.com>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Andy Gross <agross@kernel.org>
CC:     <linux-remoteproc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-stm32@st-md-mailman.stormreply.com>,
        <linux-arm-msm@vger.kernel.org>, <arnaud.pouliquen@foss.st.com>
Subject: [PATCH 7/7] rpmsg: char: Return error if user try to destroy a default endpoint.
Date:   Tue, 23 Mar 2021 13:27:37 +0100
Message-ID: <20210323122737.23035-8-arnaud.pouliquen@foss.st.com>
In-Reply-To: <20210323122737.23035-1-arnaud.pouliquen@foss.st.com>
References: <20210323122737.23035-1-arnaud.pouliquen@foss.st.com>
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Using the RPMSG_DESTROY_EPT_IOCTL control, user application can
destroy an endpoint. This patch prevents to destroy a default endpoint
associated to a channel.

This update is needed to manage the "rpmsg-raw" channel. In this
case a default endpoint is used and destroying it without the
channel does not make sense.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
---
 drivers/rpmsg/rpmsg_char.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
index 8064244f8f18..08670e94714a 100644
--- a/drivers/rpmsg/rpmsg_char.c
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -282,6 +282,10 @@ static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
 	if (cmd != RPMSG_DESTROY_EPT_IOCTL)
 		return -EINVAL;
 
+	/* Don't allow to destroy a default endpoint. */
+	if (!eptdev->rpdev || eptdev->ept == eptdev->rpdev->ept)
+		return -EPERM;
+
 	return rpmsg_chrdev_destroy_eptdev(&eptdev->dev, NULL);
 }
 
-- 
2.17.1