[PATCH] input: synaptics-rmi4: check for null rmi_dev before it is dereferenced

From: Colin Ian King <redacted>

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 <redacted>
---
 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

Hi Colin,

On Tue, Dec 20, 2016 at 10:07:50AM +0000, Colin King wrote:

From: Colin Ian King <redacted>

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")

I'd rather we removed the NULL check instead. As far as I can see it
can't even be NULL.

Thanks.

-- 
Dmitry

On 20/12/16 21:22, Dmitry Torokhov wrote:

Hi Colin,

On Tue, Dec 20, 2016 at 10:07:50AM +0000, Colin King wrote:

quoted

From: Colin Ian King <redacted>

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")

I'd rather we removed the NULL check instead. As far as I can see it
can't even be NULL.

quoted

Signed-off-by: Colin Ian King <redacted>
---
 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

Thanks.

Ignore this patch, correct fix just sent.