[PATCH v2] media: meson: vdec: potential dereference of null pointer

From: Jiasheng Jiang <jiasheng@iscas.ac.cn>
To: narmstrong@baylibre.com, mchehab@kernel.org,
	gregkh@linuxfoundation.org, khilman@baylibre.com,
	jbrunet@baylibre.com, martin.blumenstingl@googlemail.com,
	p.zabel@pengutronix.de
Cc: linux-media@vger.kernel.org, linux-amlogic@lists.infradead.org,
	linux-staging@lists.linux.dev,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Jiasheng Jiang <jiasheng@iscas.ac.cn>
Subject: [PATCH v2] media: meson: vdec: potential dereference of null pointer
Date: Fri, 10 Dec 2021 09:56:20 +0800	[thread overview]
Message-ID: <20211210015620.2143555-1-jiasheng@iscas.ac.cn> (raw)

The return value of kzalloc() needs to be checked.
To avoid use of null pointer in case of the failure of alloc.

Fixes: 876f123b8956 ("media: meson: vdec: bring up to compliance")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
---
Changelog:

v1 -> v2

*Change 1. Change the return type of amvdec_add_ts from void to int.
*Change 2. Return -ENOMEN if alloc fail and return 0 if not.
*Change 3. Modify the caller to deal with the error.
---
 drivers/staging/media/meson/vdec/esparser.c     | 6 +++++-
 drivers/staging/media/meson/vdec/vdec_helpers.c | 5 ++++-
 drivers/staging/media/meson/vdec/vdec_helpers.h | 2 +-
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/media/meson/vdec/esparser.c b/drivers/staging/media/meson/vdec/esparser.c
index db7022707ff8..7e78288cc551 100644
--- a/drivers/staging/media/meson/vdec/esparser.c
+++ b/drivers/staging/media/meson/vdec/esparser.c
@@ -328,9 +328,13 @@ esparser_queue(struct amvdec_session *sess, struct vb2_v4l2_buffer *vbuf)
 
 	offset = esparser_get_offset(sess);
 
-	amvdec_add_ts(sess, vb->timestamp, vbuf->timecode, offset, vbuf->flags);
+	ret = amvdec_add_ts(sess, vb->timestamp, vbuf->timecode, offset, vbuf->flags);
 	dev_dbg(core->dev, "esparser: ts = %llu pld_size = %u offset = %08X flags = %08X\n",
 		vb->timestamp, payload_size, offset, vbuf->flags);
+	if (ret) {
+		v4l2_m2m_buf_done(vbuf, VB2_BUF_STATE_ERROR);
+		return ret;
+	}
 
 	vbuf->flags = 0;
 	vbuf->field = V4L2_FIELD_NONE;
diff --git a/drivers/staging/media/meson/vdec/vdec_helpers.c b/drivers/staging/media/meson/vdec/vdec_helpers.c
index 7f07a9175815..972a1d1a12a5 100644
--- a/drivers/staging/media/meson/vdec/vdec_helpers.c
+++ b/drivers/staging/media/meson/vdec/vdec_helpers.c
@@ -227,13 +227,15 @@ int amvdec_set_canvases(struct amvdec_session *sess,
 }
 EXPORT_SYMBOL_GPL(amvdec_set_canvases);
 
-void amvdec_add_ts(struct amvdec_session *sess, u64 ts,
+int amvdec_add_ts(struct amvdec_session *sess, u64 ts,
+		  struct v4l2_timecode tc, u32 offset, u32 vbuf_flags)
 {
 	struct amvdec_timestamp *new_ts;
 	unsigned long flags;
 
 	new_ts = kzalloc(sizeof(*new_ts), GFP_KERNEL);
+	if (!new_ts)
+		return -ENOMEM;
 	new_ts->ts = ts;
 	new_ts->tc = tc;
 	new_ts->offset = offset;
@@ -242,6 +244,7 @@ void amvdec_add_ts(struct amvdec_session *sess, u64 ts,
 	spin_lock_irqsave(&sess->ts_spinlock, flags);
 	list_add_tail(&new_ts->list, &sess->timestamps);
 	spin_unlock_irqrestore(&sess->ts_spinlock, flags);
+	return 0;
 }
 EXPORT_SYMBOL_GPL(amvdec_add_ts);
 
diff --git a/drivers/staging/media/meson/vdec/vdec_helpers.h b/drivers/staging/media/meson/vdec/vdec_helpers.h
index cfaed52ab526..1bcb697290de 100644
--- a/drivers/staging/media/meson/vdec/vdec_helpers.h
+++ b/drivers/staging/media/meson/vdec/vdec_helpers.h
@@ -55,7 +55,7 @@ void amvdec_dst_buf_done_offset(struct amvdec_session *sess,
  * @offset: offset in the VIFIFO where the associated packet was written
  * @flags the vb2_v4l2_buffer flags
  */
-void amvdec_add_ts(struct amvdec_session *sess, u64 ts,
+int amvdec_add_ts(struct amvdec_session *sess, u64 ts,
+		  struct v4l2_timecode tc, u32 offset, u32 flags);
 void amvdec_remove_ts(struct amvdec_session *sess, u64 ts);
 
-- 
2.25.1

