linux-kernel - Re: [PATCH 08/10] staging: r8188eu: clean up the usb

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Message-ID: <1706da7b-ca98-2288-6e07-ae5912b90139@gmail.com>
Date:   Sun, 22 Aug 2021 19:17:06 +0200
From:   Michael Straube <straube.linux@...il.com>
To:     Martin Kaiser <martin@...ser.cx>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Larry Finger <Larry.Finger@...inger.net>,
        Phillip Potter <phil@...lpotter.co.uk>,
        Dan Carpenter <dan.carpenter@...cle.com>,
        linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 08/10] staging: r8188eu: clean up the usb_writeN



On 8/22/21 6:58 PM, Martin Kaiser wrote:
> Hi Michael,
> 
> Thus wrote Michael Straube (straube.linux@...il.com):
> 
>> On 8/21/21 6:48 PM, Martin Kaiser wrote:
>>> Remove unnecessary variables, check the length.
> 
>>> Signed-off-by: Martin Kaiser <martin@...ser.cx>
>>> ---
>>>    drivers/staging/r8188eu/hal/usb_ops_linux.c | 15 +++++----------
>>>    1 file changed, 5 insertions(+), 10 deletions(-)
> 
>>> diff --git a/drivers/staging/r8188eu/hal/usb_ops_linux.c b/drivers/staging/r8188eu/hal/usb_ops_linux.c
>>> index e01f1ac19596..5408383ccec3 100644
>>> --- a/drivers/staging/r8188eu/hal/usb_ops_linux.c
>>> +++ b/drivers/staging/r8188eu/hal/usb_ops_linux.c
>>> @@ -151,20 +151,15 @@ static int usb_write32(struct intf_hdl *pintfhdl, u32 addr, u32 val)
>>>    static int usb_writeN(struct intf_hdl *pintfhdl, u32 addr, u32 length, u8 *pdata)
>>>    {
>>> -	u16 wvalue;
>>> -	u16 len;
>>> +	u16 wvalue = (u16)(addr & 0x0000ffff);
>>>    	u8 buf[VENDOR_CMD_MAX_DATA_LEN] = {0};
>>> -	int ret;
>>> -
>>> +	if (length > VENDOR_CMD_MAX_DATA_LEN)
>>> +		return -EINVAL;
>>> -	wvalue = (u16)(addr & 0x0000ffff);
>>> -	len = length;
>>> -	memcpy(buf, pdata, len);
>>> +	memcpy(buf, pdata, length);
> 
>> Hi Martin, shouldn't this be
> 
>> memcpy(buf, pdata, (length & 0xffff));
> 
> I don't think this makes any difference. I've already checked that
> length <= VENDOR_CMD_MAX_DATA_LEN, which is 254. memcpy takes a size_t
> parameter for the number of bytes to copy. length will not overflow
> this.
> 
> Best regards,
> Martin
> 

Hi Martin,

ah, I see now. You are right.

Acked-by: Michael Straube <straube.linux@...il.com>


Thanks,
Michael