media: ivtv: prevent going past the hw arrays

As warned by smatch:

	drivers/media/pci/ivtv/ivtv-i2c.c:245 ivtv_i2c_register() error: buffer overflow 'hw_devicenames' 21 <= 31
	drivers/media/pci/ivtv/ivtv-i2c.c:266 ivtv_i2c_register() error: buffer overflow 'hw_addrs' 21 <= 31
	drivers/media/pci/ivtv/ivtv-i2c.c:269 ivtv_i2c_register() error: buffer overflow 'hw_addrs' 21 <= 31
	drivers/media/pci/ivtv/ivtv-i2c.c:275 ivtv_i2c_register() error: buffer overflow 'hw_addrs' 21 <= 31
	drivers/media/pci/ivtv/ivtv-i2c.c:280 ivtv_i2c_register() error: buffer overflow 'hw_addrs' 21 <= 31
	drivers/media/pci/ivtv/ivtv-i2c.c:290 ivtv_i2c_register() error: buffer overflow 'hw_addrs' 21 <= 31

The logic at ivtv_i2c_register() could let buffer overflows at
hw_devicenames and hw_addrs arrays.

This won't happen in practice due to a carefully-contructed
logic, but it is not error-prune.

Change the logic in a way that will make clearer that the
I2C hardware flags will affect the size of those two
arrays, and add an explicit check to avoid buffer overflows.

While here, use the bit macro.

Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

1 files changed, 47 insertions, 21 deletions

diff --git a/drivers/media/pci/ivtv/ivtv-cards.h b/drivers/media/pci/ivtv/ivtv-cards.h
index f3e2c5634962..c252733df340 100644
--- a/drivers/media/pci/ivtv/ivtv-cards.h
+++ b/drivers/media/pci/ivtv/ivtv-cards.h
@@ -78,27 +78,53 @@
 #define IVTV_PCI_ID_SONY		0x104d
 
 /* hardware flags, no gaps allowed */
-#define IVTV_HW_CX25840			(1 << 0)
-#define IVTV_HW_SAA7115			(1 << 1)
-#define IVTV_HW_SAA7127			(1 << 2)
-#define IVTV_HW_MSP34XX			(1 << 3)
-#define IVTV_HW_TUNER			(1 << 4)
-#define IVTV_HW_WM8775			(1 << 5)
-#define IVTV_HW_CS53L32A		(1 << 6)
-#define IVTV_HW_TVEEPROM		(1 << 7)
-#define IVTV_HW_SAA7114			(1 << 8)
-#define IVTV_HW_UPD64031A		(1 << 9)
-#define IVTV_HW_UPD6408X		(1 << 10)
-#define IVTV_HW_SAA717X			(1 << 11)
-#define IVTV_HW_WM8739			(1 << 12)
-#define IVTV_HW_VP27SMPX		(1 << 13)
-#define IVTV_HW_M52790			(1 << 14)
-#define IVTV_HW_GPIO			(1 << 15)
-#define IVTV_HW_I2C_IR_RX_AVER		(1 << 16)
-#define IVTV_HW_I2C_IR_RX_HAUP_EXT	(1 << 17) /* External before internal */
-#define IVTV_HW_I2C_IR_RX_HAUP_INT	(1 << 18)
-#define IVTV_HW_Z8F0811_IR_HAUP		(1 << 19)
-#define IVTV_HW_I2C_IR_RX_ADAPTEC	(1 << 20)
+enum ivtv_hw_bits {
+	IVTV_HW_BIT_CX25840,
+	IVTV_HW_BIT_SAA7115,
+	IVTV_HW_BIT_SAA7127,
+	IVTV_HW_BIT_MSP34XX,
+	IVTV_HW_BIT_TUNER,
+	IVTV_HW_BIT_WM8775,
+	IVTV_HW_BIT_CS53L32A,
+	IVTV_HW_BIT_TVEEPROM,
+	IVTV_HW_BIT_SAA7114,
+	IVTV_HW_BIT_UPD64031A,
+	IVTV_HW_BIT_UPD6408X,
+	IVTV_HW_BIT_SAA717X,
+	IVTV_HW_BIT_WM8739,
+	IVTV_HW_BIT_VP27SMPX,
+	IVTV_HW_BIT_M52790,
+	IVTV_HW_BIT_GPIO,
+	IVTV_HW_BIT_I2C_IR_RX_AVER,
+	IVTV_HW_BIT_I2C_IR_RX_HAUP_EXT,		 /* External before internal */
+	IVTV_HW_BIT_I2C_IR_RX_HAUP_INT,
+	IVTV_HW_BIT_Z8F0811_IR_HAUP,
+	IVTV_HW_BIT_I2C_IR_RX_ADAPTEC,
+
+	IVTV_HW_MAX_BITS	/* Should be the last one */
+};
+
+#define IVTV_HW_CX25840			BIT(IVTV_HW_BIT_CX25840)
+#define IVTV_HW_SAA7115			BIT(IVTV_HW_BIT_SAA7115)
+#define IVTV_HW_SAA7127			BIT(IVTV_HW_BIT_SAA7127)
+#define IVTV_HW_MSP34XX			BIT(IVTV_HW_BIT_MSP34XX)
+#define IVTV_HW_TUNER			BIT(IVTV_HW_BIT_TUNER)
+#define IVTV_HW_WM8775			BIT(IVTV_HW_BIT_WM8775)
+#define IVTV_HW_CS53L32A		BIT(IVTV_HW_BIT_CS53L32A)
+#define IVTV_HW_TVEEPROM		BIT(IVTV_HW_BIT_TVEEPROM)
+#define IVTV_HW_SAA7114			BIT(IVTV_HW_BIT_SAA7114)
+#define IVTV_HW_UPD64031A		BIT(IVTV_HW_BIT_UPD64031A)
+#define IVTV_HW_UPD6408X		BIT(IVTV_HW_BIT_UPD6408X)
+#define IVTV_HW_SAA717X			BIT(IVTV_HW_BIT_SAA717X)
+#define IVTV_HW_WM8739			BIT(IVTV_HW_BIT_WM8739)
+#define IVTV_HW_VP27SMPX		BIT(IVTV_HW_BIT_VP27SMPX)
+#define IVTV_HW_M52790			BIT(IVTV_HW_BIT_M52790)
+#define IVTV_HW_GPIO			BIT(IVTV_HW_BIT_GPIO)
+#define IVTV_HW_I2C_IR_RX_AVER		BIT(IVTV_HW_BIT_I2C_IR_RX_AVER)
+#define IVTV_HW_I2C_IR_RX_HAUP_EXT	BIT(IVTV_HW_BIT_I2C_IR_RX_HAUP_EXT)
+#define IVTV_HW_I2C_IR_RX_HAUP_INT	BIT(IVTV_HW_BIT_I2C_IR_RX_HAUP_INT)
+#define IVTV_HW_Z8F0811_IR_HAUP		BIT(IVTV_HW_BIT_Z8F0811_IR_HAUP)
+#define IVTV_HW_I2C_IR_RX_ADAPTEC	BIT(IVTV_HW_BIT_I2C_IR_RX_ADAPTEC)
 
 #define IVTV_HW_SAA711X   (IVTV_HW_SAA7115 | IVTV_HW_SAA7114)