[PATCH] [media] cx18: introduce a helper function to avoid array overrun

[Ethan Zhao <ethan.kernel@gmail.com>]

cx18_i2c_register() is called in cx18_init_subdevs() with index
greater than length of hw_bus array, that will cause array overrun,
introduce a helper cx18_get_max_bus_num() to avoid it.

V2: fix a typo and use ARRAY_SIZE macro

Signed-off-by: Ethan Zhao <ethan.kernel@gmail.com>
---
 drivers/media/pci/cx18/cx18-driver.c | 2 +-
 drivers/media/pci/cx18/cx18-i2c.c    | 5 +++++
 drivers/media/pci/cx18/cx18-i2c.h    | 1 +
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/media/pci/cx18/cx18-driver.c b/drivers/media/pci/cx18/cx18-driver.c
index 6386ced..dadcd4a 100644
--- a/drivers/media/pci/cx18/cx18-driver.c
+++ b/drivers/media/pci/cx18/cx18-driver.c
@@ -856,7 +856,7 @@ static void cx18_init_subdevs(struct cx18 *cx)
 	u32 device;
 	int i;
 
-	for (i = 0, device = 1; i < 32; i++, device <<= 1) {
+	for (i = 0, device = 1; i < cx18_get_max_bus_num(); i++, device <<= 1) {
 
 		if (!(device & hw))
 			continue;
diff --git a/drivers/media/pci/cx18/cx18-i2c.c b/drivers/media/pci/cx18/cx18-i2c.c
index 4af8cd6..1a7b49b 100644
--- a/drivers/media/pci/cx18/cx18-i2c.c
+++ b/drivers/media/pci/cx18/cx18-i2c.c
@@ -108,6 +108,11 @@ static int cx18_i2c_new_ir(struct cx18 *cx, struct i2c_adapter *adap, u32 hw,
 	       -1 : 0;
 }
 
+int cx18_get_max_bus_num(void)
+{
+	return ARRAY_SIZE(hw_bus);
+}
+
 int cx18_i2c_register(struct cx18 *cx, unsigned idx)
 {
 	struct v4l2_subdev *sd;
diff --git a/drivers/media/pci/cx18/cx18-i2c.h b/drivers/media/pci/cx18/cx18-i2c.h
index 1180fdc..6f2ceb5 100644
--- a/drivers/media/pci/cx18/cx18-i2c.h
+++ b/drivers/media/pci/cx18/cx18-i2c.h
@@ -21,6 +21,7 @@
  *  02111-1307  USA
  */
 
+int cx18_get_max_bus_num(void);
 int cx18_i2c_register(struct cx18 *cx, unsigned idx);
 struct v4l2_subdev *cx18_find_hw(struct cx18 *cx, u32 hw);
 
-- 
1.8.3.4 (Apple Git-47)