linux-kernel - [PATCH 2/2] media: streamzap: prevent processing IR data on URB failure

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Message-ID: <20250113105132.275-3-m.masimov@mt-integration.ru>
Date: Mon, 13 Jan 2025 13:51:31 +0300
From: Murad Masimov <m.masimov@...integration.ru>
To: Sean Young <sean@...s.org>
CC: Mauro Carvalho Chehab <mchehab@...nel.org>, Jarod Wilson
	<jarod@...hat.com>, <linux-media@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, Murad Masimov <m.masimov@...integration.ru>
Subject: [PATCH 2/2] media: streamzap: prevent processing IR data on URB failure

If streamzap_callback() receives an urb with any non-critical error
status, i.e. any error code other than -ECONNRESET, -ENOENT or -ESHUTDOWN,
it will try to process IR data, ignoring a possible transfer failure.

Make streamzap_callback() process IR data only when urb->status is 0.
Move processing logic to a separate function to make code cleaner and
more similar to the URB completion handlers in other RC drivers.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Fixes: 19770693c354 ("V4L/DVB: staging/lirc: add lirc_streamzap driver")
Signed-off-by: Murad Masimov <m.masimov@...integration.ru>
---
 drivers/media/rc/streamzap.c | 68 ++++++++++++++++++++----------------
 1 file changed, 38 insertions(+), 30 deletions(-)

diff --git a/drivers/media/rc/streamzap.c b/drivers/media/rc/streamzap.c
index 2ce62fe5d60f..d3b48a0dd1f4 100644
--- a/drivers/media/rc/streamzap.c
+++ b/drivers/media/rc/streamzap.c
@@ -138,39 +138,10 @@ static void sz_push_half_space(struct streamzap_ir *sz,
 	sz_push_full_space(sz, value & SZ_SPACE_MASK);
 }

-/*
- * streamzap_callback - usb IRQ handler callback
- *
- * This procedure is invoked on reception of data from
- * the usb remote.
- */
-static void streamzap_callback(struct urb *urb)
+static void sz_process_ir_data(struct streamzap_ir *sz, int len)
 {
-	struct streamzap_ir *sz;
 	unsigned int i;
-	int len;
-
-	if (!urb)
-		return;
-
-	sz = urb->context;
-	len = urb->actual_length;
-
-	switch (urb->status) {
-	case -ECONNRESET:
-	case -ENOENT:
-	case -ESHUTDOWN:
-		/*
-		 * this urb is terminated, clean up.
-		 * sz might already be invalid at this point
-		 */
-		dev_err(sz->dev, "urb terminated, status: %d\n", urb->status);
-		return;
-	default:
-		break;
-	}

-	dev_dbg(sz->dev, "%s: received urb, len %d\n", __func__, len);
 	for (i = 0; i < len; i++) {
 		dev_dbg(sz->dev, "sz->buf_in[%d]: %x\n",
 			i, (unsigned char)sz->buf_in[i]);
@@ -219,6 +190,43 @@ static void streamzap_callback(struct urb *urb)
 	}

 	ir_raw_event_handle(sz->rdev);
+}
+
+/*
+ * streamzap_callback - usb IRQ handler callback
+ *
+ * This procedure is invoked on reception of data from
+ * the usb remote.
+ */
+static void streamzap_callback(struct urb *urb)
+{
+	struct streamzap_ir *sz;
+	int len;
+
+	if (!urb)
+		return;
+
+	sz = urb->context;
+	len = urb->actual_length;
+
+	switch (urb->status) {
+	case 0:
+		dev_dbg(sz->dev, "%s: received urb, len %d\n", __func__, len);
+		sz_process_ir_data(sz, len);
+		break;
+	case -ECONNRESET:
+	case -ENOENT:
+	case -ESHUTDOWN:
+		/*
+		 * this urb is terminated, clean up.
+		 * sz might already be invalid at this point
+		 */
+		dev_err(sz->dev, "urb terminated, status: %d\n", urb->status);
+		return;
+	default:
+		break;
+	}
+
 	usb_submit_urb(urb, GFP_ATOMIC);
 }

--
2.39.2