linux-kernel - Re: [syzbot] [media?] WARNING in __v4l2_ctrl_modify

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Message-ID: <tencent_A536BA4B40741D769567D23CF5373096CA09@qq.com>
Date: Tue,  3 Sep 2024 10:57:55 +0800
From: Edward Adam Davis <eadavis@...com>
To: syzbot+a828133770f62293563e@...kaller.appspotmail.com
Cc: linux-kernel@...r.kernel.org,
	linux-media@...r.kernel.org,
	mchehab@...nel.org,
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [media?] WARNING in __v4l2_ctrl_modify_dimensions

The warning appears because the size passed to kvzalloc is larger than INT_MAX.

Add parameter size check before calling kvzalloc in __v4l2_ctrl_modify_dimensions.

#syz test

diff --git a/drivers/media/v4l2-core/v4l2-ctrls-api.c b/drivers/media/v4l2-core/v4l2-ctrls-api.c
index e5a364efd5e6..0b008cc94901 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls-api.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls-api.c
@@ -986,6 +986,7 @@ int __v4l2_ctrl_modify_dimensions(struct v4l2_ctrl *ctrl,
 	unsigned int elems = 1;
 	unsigned int i;
 	void *p_array;
+	unsigned int bytes;
 
 	lockdep_assert_held(ctrl->handler->lock);
 
@@ -996,7 +997,12 @@ int __v4l2_ctrl_modify_dimensions(struct v4l2_ctrl *ctrl,
 		elems *= dims[i];
 	if (elems == 0)
 		return -EINVAL;
-	p_array = kvzalloc(2 * elems * ctrl->elem_size, GFP_KERNEL);
+
+	bytes = 2 * elems * ctrl->elem_size;
+	if (unlikely(bytes > INT_MAX))
+		return -EINVAL;
+
+	p_array = kvzalloc(bytes, GFP_KERNEL);
 	if (!p_array)
 		return -ENOMEM;
 	kvfree(ctrl->p_array);