Re: [PATCH 2/2] af9035: fix broken I2C and USB I/O

[Antti Palosaari <crope@iki.fi>]

On 03.12.2013 17:06, Mauro Carvalho Chehab wrote:
> Em Wed, 27 Nov 2013 22:28:48 +0200
> Antti Palosaari <crope@iki.fi> escreveu:
>
>> There was three small buffer len calculation bugs which caused
>> driver non-working. These are coming from recent commit:
>> commit 7760e148350bf6df95662bc0db3734e9d991cb03
>> [media] af9035: Don't use dynamic static allocation
>>
>> Signed-off-by: Antti Palosaari <crope@iki.fi>
>> ---
>>   drivers/media/usb/dvb-usb-v2/af9035.c | 8 ++++----
>>   1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/media/usb/dvb-usb-v2/af9035.c b/drivers/media/usb/dvb-usb-v2/af9035.c
>> index c8fcd78..403bf43 100644
>> --- a/drivers/media/usb/dvb-usb-v2/af9035.c
>> +++ b/drivers/media/usb/dvb-usb-v2/af9035.c
>> @@ -131,7 +131,7 @@ static int af9035_wr_regs(struct dvb_usb_device *d, u32 reg, u8 *val, int len)
>>   {
>>   	u8 wbuf[MAX_XFER_SIZE];
>>   	u8 mbox = (reg >> 16) & 0xff;
>> -	struct usb_req req = { CMD_MEM_WR, mbox, sizeof(wbuf), wbuf, 0, NULL };
>> +	struct usb_req req = { CMD_MEM_WR, mbox, 6 + len, wbuf, 0, NULL };
>>
>>   	if (6 + len > sizeof(wbuf)) {
>>   		dev_warn(&d->udev->dev, "%s: i2c wr: len=%d is too big!\n",
>> @@ -238,7 +238,7 @@ static int af9035_i2c_master_xfer(struct i2c_adapter *adap,
>>   		} else {
>>   			/* I2C */
>>   			u8 buf[MAX_XFER_SIZE];
>> -			struct usb_req req = { CMD_I2C_RD, 0, sizeof(buf),
>> +			struct usb_req req = { CMD_I2C_RD, 0, 5 + msg[0].len,
>
> You should check first if msg[0].len + 5 is not bigger than sizeof(buf).
>
>>   					buf, msg[1].len, msg[1].buf };
>>
>>   			if (5 + msg[0].len > sizeof(buf)) {

Could you explain why? Why it is not enough to check it later as it is 
done in line just top of that text?



>> @@ -274,8 +274,8 @@ static int af9035_i2c_master_xfer(struct i2c_adapter *adap,
>>   		} else {
>>   			/* I2C */
>>   			u8 buf[MAX_XFER_SIZE];
>> -			struct usb_req req = { CMD_I2C_WR, 0, sizeof(buf), buf,
>> -					0, NULL };
>> +			struct usb_req req = { CMD_I2C_WR, 0, 5 + msg[0].len,
>> +					buf, 0, NULL };
>
> Same here: you should check first if msg[0].len + 5 is not bigger than sizeof(buf).
>
>>
>>   			if (5 + msg[0].len > sizeof(buf)) {
>>   				dev_warn(&d->udev->dev,

Same here. I don't really see your point.

Antti


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