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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.7 012/376] media: v4l2-ctrls: v4l2_ctrl_g/s_ctrl*(): dont continue when WARN_ON
Date:   Fri, 19 Jun 2020 16:28:50 +0200
Message-Id: <20200619141710.943422485@linuxfoundation.org>
In-Reply-To: <20200619141710.350494719@linuxfoundation.org>
References: <20200619141710.350494719@linuxfoundation.org>
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From: Hans Verkuil <hverkuil-cisco@xs4all.nl>

[ Upstream commit 7c3bae3f430af6b4fcbdb7272e191e266fd94b45 ]

If the v4l2_ctrl_g_ctrl*() or __v4l2_ctrl_s_ctrl*() functions
are called for the wrong control type then they call WARN_ON
since that is a driver error. But they still continue, potentially
overwriting data. Change this to return an error (s_ctrl) or 0
(g_ctrl), just to be safe.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/media/v4l2-core/v4l2-ctrls.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
index 93d33d1db4e8..452edd06d67d 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -3794,7 +3794,8 @@ s32 v4l2_ctrl_g_ctrl(struct v4l2_ctrl *ctrl)
 	struct v4l2_ext_control c;
 
 	/* It's a driver bug if this happens. */
-	WARN_ON(!ctrl->is_int);
+	if (WARN_ON(!ctrl->is_int))
+		return 0;
 	c.value = 0;
 	get_ctrl(ctrl, &c);
 	return c.value;
@@ -3806,7 +3807,8 @@ s64 v4l2_ctrl_g_ctrl_int64(struct v4l2_ctrl *ctrl)
 	struct v4l2_ext_control c;
 
 	/* It's a driver bug if this happens. */
-	WARN_ON(ctrl->is_ptr || ctrl->type != V4L2_CTRL_TYPE_INTEGER64);
+	if (WARN_ON(ctrl->is_ptr || ctrl->type != V4L2_CTRL_TYPE_INTEGER64))
+		return 0;
 	c.value64 = 0;
 	get_ctrl(ctrl, &c);
 	return c.value64;
@@ -4215,7 +4217,8 @@ int __v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val)
 	lockdep_assert_held(ctrl->handler->lock);
 
 	/* It's a driver bug if this happens. */
-	WARN_ON(!ctrl->is_int);
+	if (WARN_ON(!ctrl->is_int))
+		return -EINVAL;
 	ctrl->val = val;
 	return set_ctrl(NULL, ctrl, 0);
 }
@@ -4226,7 +4229,8 @@ int __v4l2_ctrl_s_ctrl_int64(struct v4l2_ctrl *ctrl, s64 val)
 	lockdep_assert_held(ctrl->handler->lock);
 
 	/* It's a driver bug if this happens. */
-	WARN_ON(ctrl->is_ptr || ctrl->type != V4L2_CTRL_TYPE_INTEGER64);
+	if (WARN_ON(ctrl->is_ptr || ctrl->type != V4L2_CTRL_TYPE_INTEGER64))
+		return -EINVAL;
 	*ctrl->p_new.p_s64 = val;
 	return set_ctrl(NULL, ctrl, 0);
 }
@@ -4237,7 +4241,8 @@ int __v4l2_ctrl_s_ctrl_string(struct v4l2_ctrl *ctrl, const char *s)
 	lockdep_assert_held(ctrl->handler->lock);
 
 	/* It's a driver bug if this happens. */
-	WARN_ON(ctrl->type != V4L2_CTRL_TYPE_STRING);
+	if (WARN_ON(ctrl->type != V4L2_CTRL_TYPE_STRING))
+		return -EINVAL;
 	strscpy(ctrl->p_new.p_char, s, ctrl->maximum + 1);
 	return set_ctrl(NULL, ctrl, 0);
 }
@@ -4249,7 +4254,8 @@ int __v4l2_ctrl_s_ctrl_area(struct v4l2_ctrl *ctrl,
 	lockdep_assert_held(ctrl->handler->lock);
 
 	/* It's a driver bug if this happens. */
-	WARN_ON(ctrl->type != V4L2_CTRL_TYPE_AREA);
+	if (WARN_ON(ctrl->type != V4L2_CTRL_TYPE_AREA))
+		return -EINVAL;
 	*ctrl->p_new.p_area = *area;
 	return set_ctrl(NULL, ctrl, 0);
 }
-- 
2.25.1