linux-kernel - [PATCH] input: synaptics-rmi4: check for null rmi

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Date:   Tue, 20 Dec 2016 10:07:50 +0000
From:   Colin King <colin.king@...onical.com>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Andrew Duggan <aduggan@...aptics.com>,
        Benjamin Tissoires <benjamin.tissoires@...hat.com>,
        Lyude Paul <thatslyude@...il.com>,
        Dennis Wassenberg <dennis.wassenberg@...unet.com>,
        linux-input@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org
Subject: [PATCH] input: synaptics-rmi4: check for null rmi_dev before it is dereferenced

From: Colin Ian King <colin.king@...onical.com>

rmi_dev is currently being dereferenced before it null checked, so we
have a potential null pointer dereference issue with this.  Fix this
by dereferencing rmi_dev after a null check has been performed.

Fixes CoverityScan CID 1391218 ("Dereference before null check")

Signed-off-by: Colin Ian King <colin.king@...onical.com>
---
 drivers/input/rmi4/rmi_f03.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/input/rmi4/rmi_f03.c b/drivers/input/rmi4/rmi_f03.c
index 8a7ca3e..008f42a 100644
--- a/drivers/input/rmi4/rmi_f03.c
+++ b/drivers/input/rmi4/rmi_f03.c
@@ -164,7 +164,7 @@ static int rmi_f03_config(struct rmi_function *fn)
 static int rmi_f03_attention(struct rmi_function *fn, unsigned long *irq_bits)
 {
 	struct rmi_device *rmi_dev = fn->rmi_dev;
-	struct rmi_driver_data *drvdata = dev_get_drvdata(&rmi_dev->dev);
+	struct rmi_driver_data *drvdata;
 	struct f03_data *f03 = dev_get_drvdata(&fn->dev);
 	u16 data_addr = fn->fd.data_base_addr;
 	const u8 ob_len = f03->rx_queue_length * RMI_F03_OB_SIZE;
@@ -178,6 +178,7 @@ static int rmi_f03_attention(struct rmi_function *fn, unsigned long *irq_bits)
 	if (!rmi_dev)
 		return -ENODEV;
 
+	drvdata = dev_get_drvdata(&rmi_dev->dev);
 	if (drvdata->attn_data.data) {
 		/* First grab the data passed by the transport device */
 		if (drvdata->attn_data.size < ob_len) {
-- 
2.10.2