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Date:   Fri, 6 May 2022 19:33:20 +0800
From:   Wang Cheng <wanngchenng@gmail.com>
To:     Pavel Skripkin <paskripkin@gmail.com>
Cc:     dan.carpenter@oracle.com, linux-staging@lists.linux.dev,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/2] staging: rtl8712: fix uninit-value in
 r871xu_drv_init()
Message-ID: <20220506113320.gc6zryhm7uqnbva5@ppc.localdomain>
References: <cover.1651760402.git.wanngchenng@gmail.com>
 <14c3886173dfa4597f0704547c414cfdbcd11d16.1651760402.git.wanngchenng@gmail.com>
 <46b89616-5ec7-fb04-f561-2647efd968c4@gmail.com>
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On 22/05/06 10:41AM, Pavel Skripkin wrote:
> Hi Wang,
> 
> On 5/6/22 06:16, Wang Cheng wrote:
> 
> [snip]
> 
> > 
> > Reported-and-tested-by: syzbot+6f5ecd144854c0d8580b@syzkaller.appspotmail.com
> > Signed-off-by: Wang Cheng <wanngchenng@gmail.com>
> > ---
> >   drivers/staging/rtl8712/usb_intf.c | 6 +++---
> >   1 file changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/staging/rtl8712/usb_intf.c b/drivers/staging/rtl8712/usb_intf.c
> > index ee4c61f85a07..50dcd3ecb685 100644
> > --- a/drivers/staging/rtl8712/usb_intf.c
> > +++ b/drivers/staging/rtl8712/usb_intf.c
> > @@ -538,13 +538,13 @@ static int r871xu_drv_init(struct usb_interface *pusb_intf,
> >   		} else {
> >   			AutoloadFail = false;
> >   		}
> > -		if (((mac[0] == 0xff) && (mac[1] == 0xff) &&
> > +		if ((!AutoloadFail) ||
> > +		    ((mac[0] == 0xff) && (mac[1] == 0xff) &&
> >   		     (mac[2] == 0xff) && (mac[3] == 0xff) &&
> >   		     (mac[4] == 0xff) && (mac[5] == 0xff)) ||
> >   		    ((mac[0] == 0x00) && (mac[1] == 0x00) &&
> >   		     (mac[2] == 0x00) && (mac[3] == 0x00) &&
> > -		     (mac[4] == 0x00) && (mac[5] == 0x00)) ||
> > -		     (!AutoloadFail)) {
> > +		     (mac[4] == 0x00) && (mac[5] == 0x00))) {
> 
> 
> That looks ugly. I mean mac checks. Can we, please, use sane kernel API like
> is_valid_ether_addr()?

Good idea! But will is_valid_ether_addr() check a larger range?
The comment of is_valid_ether_addr()(include/linux/etherdevice.h) says:
  Check that the Ethernet address (MAC) is not 00:00:00:00:00:00, is not
  a *multicast address*, and is not FF:FF:FF:FF:FF:FF.

thanks,
- w

> 
> 
> >   			mac[0] = 0x00;
> >   			mac[1] = 0xe0;
> >   			mac[2] = 0x4c;
> 
> 
> 
> 
> With regards,
> Pavel Skripkin