[PATCH v2 0/2] staging: rtl8712: fix uninit-value 'data' and 'mac'

[PATCH v2 0/2] staging: rtl8712: fix uninit-value 'data' and 'mac'

[Wang Cheng]

This is a v2 patch to fix KMSAN: uninit-value in r871xu_drv_init,
https://syzkaller.appspot.com/bug?id=3cd92b1d85428b128503bfa7a250294c9ae00bd8
Previous version and discussion could be seen here:
https://lore.kernel.org/all/20220414141223.qwiznrwgjyywngfg@ppc.localdomain/

Changelog v1->v2:
- Split to two patches.
- Add kmsan reports.
- Fix uninit-value 'data' by adding error checking and initialization
  rather than changing logic of r8712_usbctrl_vendorreq().

Wang Cheng (2):
  staging: rtl8712: fix uninit-value in usb_read8() and friends
  staging: rtl8712: fix uninit-value in r871xu_drv_init()

 drivers/staging/rtl8712/usb_intf.c |  6 +++---
 drivers/staging/rtl8712/usb_ops.c  | 27 ++++++++++++++++++---------
 2 files changed, 21 insertions(+), 12 deletions(-)

-- 
2.33.1

[PATCH v2 1/2] staging: rtl8712: fix uninit-value in usb_read8() and friends

[Wang Cheng]

When r8712_usbctrl_vendorreq() returns negative, 'data' in
usb_read{8,16,32} will not be initialized.

BUG: KMSAN: uninit-value in string_nocheck lib/vsprintf.c:643 [inline]
BUG: KMSAN: uninit-value in string+0x4ec/0x6f0 lib/vsprintf.c:725
 string_nocheck lib/vsprintf.c:643 [inline]
 string+0x4ec/0x6f0 lib/vsprintf.c:725
 vsnprintf+0x2222/0x3650 lib/vsprintf.c:2806
 va_format lib/vsprintf.c:1704 [inline]
 pointer+0x18e6/0x1f70 lib/vsprintf.c:2443
 vsnprintf+0x1a9b/0x3650 lib/vsprintf.c:2810
 vprintk_store+0x537/0x2150 kernel/printk/printk.c:2158
 vprintk_emit+0x28b/0xab0 kernel/printk/printk.c:2256
 dev_vprintk_emit+0x5ef/0x6d0 drivers/base/core.c:4604
 dev_printk_emit+0x1dd/0x21f drivers/base/core.c:4615
 __dev_printk+0x3be/0x440 drivers/base/core.c:4627
 _dev_info+0x1ea/0x22f drivers/base/core.c:4673
 r871xu_drv_init+0x1929/0x3070 drivers/staging/rtl8712/usb_intf.c:401
 usb_probe_interface+0xf19/0x1600 drivers/usb/core/driver.c:396
 really_probe+0x6c7/0x1350 drivers/base/dd.c:621
 __driver_probe_device+0x3e9/0x530 drivers/base/dd.c:752
 driver_probe_device drivers/base/dd.c:782 [inline]
 __device_attach_driver+0x79f/0x1120 drivers/base/dd.c:899
 bus_for_each_drv+0x2d6/0x3f0 drivers/base/bus.c:427
 __device_attach+0x593/0x8e0 drivers/base/dd.c:970
 device_initial_probe+0x4a/0x60 drivers/base/dd.c:1017
 bus_probe_device+0x17b/0x3e0 drivers/base/bus.c:487
 device_add+0x1fff/0x26e0 drivers/base/core.c:3405
 usb_set_configuration+0x37e9/0x3ed0 drivers/usb/core/message.c:2170
 usb_generic_driver_probe+0x13c/0x300 drivers/usb/core/generic.c:238
 usb_probe_device+0x309/0x570 drivers/usb/core/driver.c:293
 really_probe+0x6c7/0x1350 drivers/base/dd.c:621
 __driver_probe_device+0x3e9/0x530 drivers/base/dd.c:752
 driver_probe_device drivers/base/dd.c:782 [inline]
 __device_attach_driver+0x79f/0x1120 drivers/base/dd.c:899
 bus_for_each_drv+0x2d6/0x3f0 drivers/base/bus.c:427
 __device_attach+0x593/0x8e0 drivers/base/dd.c:970
 device_initial_probe+0x4a/0x60 drivers/base/dd.c:1017
 bus_probe_device+0x17b/0x3e0 drivers/base/bus.c:487
 device_add+0x1fff/0x26e0 drivers/base/core.c:3405
 usb_new_device+0x1b91/0x2950 drivers/usb/core/hub.c:2566
 hub_port_connect drivers/usb/core/hub.c:5363 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5507 [inline]
 port_event drivers/usb/core/hub.c:5665 [inline]
 hub_event+0x58e3/0x89e0 drivers/usb/core/hub.c:5747
 process_one_work+0xdb6/0x1820 kernel/workqueue.c:2289
 worker_thread+0x10d0/0x2240 kernel/workqueue.c:2436
 kthread+0x3c7/0x500 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30

Local variable data created at:
 usb_read8+0x5d/0x130 drivers/staging/rtl8712/usb_ops.c:33
 r8712_read8+0xa5/0xd0 drivers/staging/rtl8712/rtl8712_io.c:29

Reported-and-tested-by: syzbot+6f5ecd144854c0d8580b@syzkaller.appspotmail.com
Signed-off-by: Wang Cheng <wanngchenng@gmail.com>
---
 drivers/staging/rtl8712/usb_ops.c | 27 ++++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/drivers/staging/rtl8712/usb_ops.c b/drivers/staging/rtl8712/usb_ops.c
index e64845e6adf3..af9966d03979 100644
--- a/drivers/staging/rtl8712/usb_ops.c
+++ b/drivers/staging/rtl8712/usb_ops.c
@@ -29,7 +29,8 @@ static u8 usb_read8(struct intf_hdl *intfhdl, u32 addr)
 	u16 wvalue;
 	u16 index;
 	u16 len;
-	__le32 data;
+	int status;
+	__le32 data = 0;
 	struct intf_priv *intfpriv = intfhdl->pintfpriv;
 
 	request = 0x05;
@@ -37,8 +38,10 @@ static u8 usb_read8(struct intf_hdl *intfhdl, u32 addr)
 	index = 0;
 	wvalue = (u16)(addr & 0x0000ffff);
 	len = 1;
-	r8712_usbctrl_vendorreq(intfpriv, request, wvalue, index, &data, len,
-				requesttype);
+	status = r8712_usbctrl_vendorreq(intfpriv, request, wvalue, index,
+					 &data, len, requesttype);
+	if (status < 0)
+		return 0;
 	return (u8)(le32_to_cpu(data) & 0x0ff);
 }
 
@@ -49,7 +52,8 @@ static u16 usb_read16(struct intf_hdl *intfhdl, u32 addr)
 	u16 wvalue;
 	u16 index;
 	u16 len;
-	__le32 data;
+	int status;
+	__le32 data = 0;
 	struct intf_priv *intfpriv = intfhdl->pintfpriv;
 
 	request = 0x05;
@@ -57,8 +61,10 @@ static u16 usb_read16(struct intf_hdl *intfhdl, u32 addr)
 	index = 0;
 	wvalue = (u16)(addr & 0x0000ffff);
 	len = 2;
-	r8712_usbctrl_vendorreq(intfpriv, request, wvalue, index, &data, len,
-				requesttype);
+	status = r8712_usbctrl_vendorreq(intfpriv, request, wvalue, index,
+					 &data, len, requesttype);
+	if (status < 0)
+		return 0;
 	return (u16)(le32_to_cpu(data) & 0xffff);
 }
 
@@ -69,7 +75,8 @@ static u32 usb_read32(struct intf_hdl *intfhdl, u32 addr)
 	u16 wvalue;
 	u16 index;
 	u16 len;
-	__le32 data;
+	int status;
+	__le32 data = 0;
 	struct intf_priv *intfpriv = intfhdl->pintfpriv;
 
 	request = 0x05;
@@ -77,8 +84,10 @@ static u32 usb_read32(struct intf_hdl *intfhdl, u32 addr)
 	index = 0;
 	wvalue = (u16)(addr & 0x0000ffff);
 	len = 4;
-	r8712_usbctrl_vendorreq(intfpriv, request, wvalue, index, &data, len,
-				requesttype);
+	status = r8712_usbctrl_vendorreq(intfpriv, request, wvalue, index,
+					 &data, len, requesttype);
+	if (status < 0)
+		return 0;
 	return le32_to_cpu(data);
 }
 
-- 
2.33.1

[PATCH v2 2/2] staging: rtl8712: fix uninit-value in r871xu_drv_init()

[Wang Cheng]

When 'tmpU1b' returns from r8712_read8(padapter, EE_9346CR) is 0,
'mac[6]' will not be initialized.

BUG: KMSAN: uninit-value in r871xu_drv_init+0x2d54/0x3070 drivers/staging/rtl8712/usb_intf.c:541
 r871xu_drv_init+0x2d54/0x3070 drivers/staging/rtl8712/usb_intf.c:541
 usb_probe_interface+0xf19/0x1600 drivers/usb/core/driver.c:396
 really_probe+0x653/0x14b0 drivers/base/dd.c:596
 __driver_probe_device+0x3e9/0x530 drivers/base/dd.c:752
 driver_probe_device drivers/base/dd.c:782 [inline]
 __device_attach_driver+0x79f/0x1120 drivers/base/dd.c:899
 bus_for_each_drv+0x2d6/0x3f0 drivers/base/bus.c:427
 __device_attach+0x593/0x8e0 drivers/base/dd.c:970
 device_initial_probe+0x4a/0x60 drivers/base/dd.c:1017
 bus_probe_device+0x17b/0x3e0 drivers/base/bus.c:487
 device_add+0x1fff/0x26e0 drivers/base/core.c:3405
 usb_set_configuration+0x37e9/0x3ed0 drivers/usb/core/message.c:2170
 usb_generic_driver_probe+0x13c/0x300 drivers/usb/core/generic.c:238
 usb_probe_device+0x309/0x570 drivers/usb/core/driver.c:293
 really_probe+0x653/0x14b0 drivers/base/dd.c:596
 __driver_probe_device+0x3e9/0x530 drivers/base/dd.c:752
 driver_probe_device drivers/base/dd.c:782 [inline]
 __device_attach_driver+0x79f/0x1120 drivers/base/dd.c:899
 bus_for_each_drv+0x2d6/0x3f0 drivers/base/bus.c:427
 __device_attach+0x593/0x8e0 drivers/base/dd.c:970
 device_initial_probe+0x4a/0x60 drivers/base/dd.c:1017
 bus_probe_device+0x17b/0x3e0 drivers/base/bus.c:487
 device_add+0x1fff/0x26e0 drivers/base/core.c:3405
 usb_new_device+0x1b8e/0x2950 drivers/usb/core/hub.c:2566
 hub_port_connect drivers/usb/core/hub.c:5358 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5502 [inline]
 port_event drivers/usb/core/hub.c:5660 [inline]
 hub_event+0x58e3/0x89e0 drivers/usb/core/hub.c:5742
 process_one_work+0xdb6/0x1820 kernel/workqueue.c:2307
 worker_thread+0x10b3/0x21e0 kernel/workqueue.c:2454
 kthread+0x3c7/0x500 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30

Local variable mac created at:
 r871xu_drv_init+0x1771/0x3070 drivers/staging/rtl8712/usb_intf.c:394
 usb_probe_interface+0xf19/0x1600 drivers/usb/core/driver.c:396

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))) {
 			mac[0] = 0x00;
 			mac[1] = 0xe0;
 			mac[2] = 0x4c;
-- 
2.33.1

Re: [PATCH v2 1/2] staging: rtl8712: fix uninit-value in usb_read8() and friends

[Dan Carpenter]

Setting "data = 0" will silence the KMSAN warnings but it doesn't fix
the bug which is that r8712_usbctrl_vendorreq() treats partial reads
as success.

The usb_control_msg() returns negatives on total failure and it returns
small positives on partial failure.  So take the code that I gave you
before and put that into r8712_usbctrl_vendorreq().  That's patch 1.
These patches become 2 and 3.

        status = usb_control_msg();
        if (status < 0)
                goto free;
        if (status != len) {
                status = -EREMOTEIO;
                goto free;
        }
        if (requesttype == 0x01)
                memcpy(pdata, pIo_buf, status);

regards,
dan carpenter

Re: [PATCH v2 1/2] staging: rtl8712: fix uninit-value in usb_read8() and friends

[Pavel Skripkin]

Hi Wang,

On 5/6/22 06:15, Wang Cheng wrote:
> When r8712_usbctrl_vendorreq() returns negative, 'data' in
> usb_read{8,16,32} will not be initialized.

[code snip]

> +	status = r8712_usbctrl_vendorreq(intfpriv, request, wvalue, index,
> +					 &data, len, requesttype);
> +	if (status < 0)
> +		return 0;
>   	return le32_to_cpu(data);
>   }
>   

Why do you believe that 0 is not valid register value? And if it's 
possible then how you can identify an error?




With regards,
Pavel Skripkin

Re: [PATCH v2 2/2] staging: rtl8712: fix uninit-value in r871xu_drv_init()

[Pavel Skripkin]

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()?


>   			mac[0] = 0x00;
>   			mac[1] = 0xe0;
>   			mac[2] = 0x4c;




With regards,
Pavel Skripkin

Re: [PATCH v2 1/2] staging: rtl8712: fix uninit-value in usb_read8() and friends

[Dan Carpenter]

On Fri, May 06, 2022 at 10:23:39AM +0300, Pavel Skripkin wrote:
> Hi Wang,
> 
> On 5/6/22 06:15, Wang Cheng wrote:
> > When r8712_usbctrl_vendorreq() returns negative, 'data' in
> > usb_read{8,16,32} will not be initialized.
> 
> [code snip]
> 
> > +	status = r8712_usbctrl_vendorreq(intfpriv, request, wvalue, index,
> > +					 &data, len, requesttype);
> > +	if (status < 0)
> > +		return 0;
> >   	return le32_to_cpu(data);
> >   }
> 
> Why do you believe that 0 is not valid register value? And if it's possible
> then how you can identify an error?

I think you are getting data and status mixed up?

regards,
dan carpenter

Re: [PATCH v2 1/2] staging: rtl8712: fix uninit-value in usb_read8() and friends

[Wang Cheng]

On 22/05/06 10:10AM, Dan Carpenter wrote:
> Setting "data = 0" will silence the KMSAN warnings but it doesn't fix
> the bug which is that r8712_usbctrl_vendorreq() treats partial reads
> as success.
> 
> The usb_control_msg() returns negatives on total failure and it returns
> small positives on partial failure.  So take the code that I gave you
> before and put that into r8712_usbctrl_vendorreq().  That's patch 1.
> These patches become 2 and 3.

Ah, you mentioned in previous review "But then another problem is that
"status" can be less than "len"." I missed it then.

- w

> 
>         status = usb_control_msg();
>         if (status < 0)
>                 goto free;
>         if (status != len) {
>                 status = -EREMOTEIO;
>                 goto free;
>         }
>         if (requesttype == 0x01)
>                 memcpy(pdata, pIo_buf, status);
> 
> regards,
> dan carpenter
> 

Re: [PATCH v2 2/2] staging: rtl8712: fix uninit-value in r871xu_drv_init()

[Wang Cheng]

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

Re: [PATCH v2 2/2] staging: rtl8712: fix uninit-value in r871xu_drv_init()

[Wang Cheng]

On 22/05/06 07:33PM, Wang Cheng wrote:
> 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.

is_zero_ether_addr() in etherdevice.h could check the all zero mac address.

thanks,
- w

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

Re: [PATCH v2 2/2] staging: rtl8712: fix uninit-value in r871xu_drv_init()

[Pavel Skripkin]

[-- Attachment #1.1: Type: text/plain, Size: 1953 bytes --]

Hi Wang,

On 5/6/22 14:33, Wang Cheng wrote:
> 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.
> 

I am not good an expert at networking stuff, but can multicast mac 
address be valid for purpose of Wi-Fi adapter? IIUC it's can't, but as I 
said before, I am not an expert



With regards,
Pavel Skripkin

[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 840 bytes --]

Re: [PATCH v2 2/2] staging: rtl8712: fix uninit-value in r871xu_drv_init()

[Wang Cheng]

On 22/05/06 03:02PM, Pavel Skripkin wrote:
> Hi Wang,
> 
> On 5/6/22 14:33, Wang Cheng wrote:
> > 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.
> > 
> 
> I am not good an expert at networking stuff, but can multicast mac address
> be valid for purpose of Wi-Fi adapter? IIUC it's can't, but as I said
> before, I am not an expert

Me neither. :P I found some reference here:
https://en.wikipedia.org/wiki/Multicast_address#Ethernet

And in the implementation of
is_multicast_ether_addr()(include/linux/etherdevice.h), it checks one
bit of mac address to determine a multicast or not.

Probably some other kernel API could help.

thanks,
- w