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>

diff --git a/drivers/media/pci/ivtv/ivtv-cards.h b/drivers/media/pci/ivtv/ivtv-cards.h
index f3e2c56..c252733 100644 (file)
--- 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)
 

diff --git a/drivers/media/pci/ivtv/ivtv-i2c.c b/drivers/media/pci/ivtv/ivtv-i2c.c
index 982045c..c052c57 100644 (file)
--- a/drivers/media/pci/ivtv/ivtv-i2c.c
+++ b/drivers/media/pci/ivtv/ivtv-i2c.c
@@ -85,7 +85,7 @@
 #define IVTV_ADAPTEC_IR_ADDR           0x6b
 
 /* This array should match the IVTV_HW_ defines */
-static const u8 hw_addrs[] = {
+static const u8 hw_addrs[IVTV_HW_MAX_BITS] = {
        IVTV_CX25840_I2C_ADDR,
        IVTV_SAA7115_I2C_ADDR,
        IVTV_SAA7127_I2C_ADDR,
@@ -110,7 +110,7 @@ static const u8 hw_addrs[] = {
 };
 
 /* This array should match the IVTV_HW_ defines */
-static const char * const hw_devicenames[] = {
+static const char * const hw_devicenames[IVTV_HW_MAX_BITS] = {
        "cx25840",
        "saa7115",
        "saa7127_auto", /* saa7127 or saa7129 */
@@ -240,10 +240,16 @@ void ivtv_i2c_new_ir_legacy(struct ivtv *itv)
 
 int ivtv_i2c_register(struct ivtv *itv, unsigned idx)
 {
-       struct v4l2_subdev *sd;
        struct i2c_adapter *adap = &itv->i2c_adap;
-       const char *type = hw_devicenames[idx];
-       u32 hw = 1 << idx;
+       struct v4l2_subdev *sd;
+       const char *type;
+       u32 hw;
+
+       if (idx >= IVTV_HW_MAX_BITS)
+               return -ENODEV;
+
+       type = hw_devicenames[idx];
+       hw = 1 << idx;
 
        if (hw == IVTV_HW_TUNER) {
                /* special tuner handling */