diff mbox series

[2/2,next] net: usb: asix: ax88772: net: Fix less than zero comparison of a u16

Message ID 20210608152249.160333-2-colin.king@canonical.com (mailing list archive)
State Superseded
Headers show
Series [1/2,next] net: usb: asix: Fix less than zero comparison of a u16 | expand

Commit Message

Colin King June 8, 2021, 3:22 p.m. UTC 
From: Colin Ian King <colin.king@canonical.com>

The comparison of the u16 priv->phy_addr < 0 is always false because
phy_addr is unsigned. Fix this by assigning the return from the call
to function asix_read_phy_addr to int ret and using this for the
less than zero error check comparison.

Addresses-Coverity: ("Unsigned compared against 0")
Fixes: 7e88b11a862a ("net: usb: asix: refactor asix_read_phy_addr() and handle errors on return")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/net/usb/ax88172a.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Oleksij Rempel June 8, 2021, 6:11 p.m. UTC | #1 
On Tue, Jun 08, 2021 at 04:22:49PM +0100, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> The comparison of the u16 priv->phy_addr < 0 is always false because
> phy_addr is unsigned. Fix this by assigning the return from the call
> to function asix_read_phy_addr to int ret and using this for the
> less than zero error check comparison.
> 
> Addresses-Coverity: ("Unsigned compared against 0")
> Fixes: 7e88b11a862a ("net: usb: asix: refactor asix_read_phy_addr() and handle errors on return")

Here is wrong Fixes tag. This assignment was bogus before this patch.

> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  drivers/net/usb/ax88172a.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/usb/ax88172a.c b/drivers/net/usb/ax88172a.c
> index 2e2081346740..e24773bb9398 100644
> --- a/drivers/net/usb/ax88172a.c
> +++ b/drivers/net/usb/ax88172a.c
> @@ -205,7 +205,8 @@ static int ax88172a_bind(struct usbnet *dev, struct usb_interface *intf)
>  		goto free;
>  	}
>  
> -	priv->phy_addr = asix_read_phy_addr(dev, priv->use_embdphy);
> +	ret = asix_read_phy_addr(dev, priv->use_embdphy);
> +	priv->phy_addr = ret;

Ah.. it is same bug in different color :)
You probably wonted to do:
	if (ret < 0)
		goto free;

	priv->phy_addr = ret;

>  	if (priv->phy_addr < 0) {
>  		ret = priv->phy_addr;
>  		goto free;
> -- 
> 2.31.1
> 
>
Colin King June 9, 2021, 9:51 a.m. UTC | #2 
On 08/06/2021 19:11, Oleksij Rempel wrote:
> On Tue, Jun 08, 2021 at 04:22:49PM +0100, Colin King wrote:
>> From: Colin Ian King <colin.king@canonical.com>
>>
>> The comparison of the u16 priv->phy_addr < 0 is always false because
>> phy_addr is unsigned. Fix this by assigning the return from the call
>> to function asix_read_phy_addr to int ret and using this for the
>> less than zero error check comparison.
>>
>> Addresses-Coverity: ("Unsigned compared against 0")
>> Fixes: 7e88b11a862a ("net: usb: asix: refactor asix_read_phy_addr() and handle errors on return")
> 
> Here is wrong Fixes tag. This assignment was bogus before this patch.

I'm not sure that's correct, that commit has the following change in it:

diff --git a/drivers/net/usb/ax88172a.c b/drivers/net/usb/ax88172a.c
index b404c9462dce..c8ca5187eece 100644
--- a/drivers/net/usb/ax88172a.c
+++ b/drivers/net/usb/ax88172a.c
@@ -220,6 +220,11 @@ static int ax88172a_bind(struct usbnet *dev, struct
usb_interface *intf)
        }

        priv->phy_addr = asix_read_phy_addr(dev, priv->use_embdphy);
+       if (priv->phy_addr < 0) {
+               ret = priv->phy_addr;
+               goto free;
+       }
+


> 
>> Signed-off-by: Colin Ian King <colin.king@canonical.com>
>> ---
>>  drivers/net/usb/ax88172a.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/usb/ax88172a.c b/drivers/net/usb/ax88172a.c
>> index 2e2081346740..e24773bb9398 100644
>> --- a/drivers/net/usb/ax88172a.c
>> +++ b/drivers/net/usb/ax88172a.c
>> @@ -205,7 +205,8 @@ static int ax88172a_bind(struct usbnet *dev, struct usb_interface *intf)
>>  		goto free;
>>  	}
>>  
>> -	priv->phy_addr = asix_read_phy_addr(dev, priv->use_embdphy);
>> +	ret = asix_read_phy_addr(dev, priv->use_embdphy);
>> +	priv->phy_addr = ret;
> 
> Ah.. it is same bug in different color :)
> You probably wonted to do:
> 	if (ret < 0)
> 		goto free;
> 
> 	priv->phy_addr = ret;

Doh, brain failure of mine. I'll send a V2 later today.

> 
>>  	if (priv->phy_addr < 0) {
>>  		ret = priv->phy_addr;
>>  		goto free;
>> -- 
>> 2.31.1
>>
>>
>
Oleksij Rempel June 9, 2021, 11:52 a.m. UTC | #3 
On Wed, Jun 09, 2021 at 10:51:09AM +0100, Colin Ian King wrote:
> On 08/06/2021 19:11, Oleksij Rempel wrote:
> > On Tue, Jun 08, 2021 at 04:22:49PM +0100, Colin King wrote:
> >> From: Colin Ian King <colin.king@canonical.com>
> >>
> >> The comparison of the u16 priv->phy_addr < 0 is always false because
> >> phy_addr is unsigned. Fix this by assigning the return from the call
> >> to function asix_read_phy_addr to int ret and using this for the
> >> less than zero error check comparison.
> >>
> >> Addresses-Coverity: ("Unsigned compared against 0")
> >> Fixes: 7e88b11a862a ("net: usb: asix: refactor asix_read_phy_addr() and handle errors on return")
> > 
> > Here is wrong Fixes tag. This assignment was bogus before this patch.
> 
> I'm not sure that's correct, that commit has the following change in it:
> 
> diff --git a/drivers/net/usb/ax88172a.c b/drivers/net/usb/ax88172a.c
> index b404c9462dce..c8ca5187eece 100644
> --- a/drivers/net/usb/ax88172a.c
> +++ b/drivers/net/usb/ax88172a.c
> @@ -220,6 +220,11 @@ static int ax88172a_bind(struct usbnet *dev, struct
> usb_interface *intf)
>         }
> 
>         priv->phy_addr = asix_read_phy_addr(dev, priv->use_embdphy);
> +       if (priv->phy_addr < 0) {
> +               ret = priv->phy_addr;
> +               goto free;
> +       }
> +
> 

Even before my patch asix_read_phy_addr() was returning different
error values. My patch just add check for the return value.

> > 
> >> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> >> ---
> >>  drivers/net/usb/ax88172a.c | 3 ++-
> >>  1 file changed, 2 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/net/usb/ax88172a.c b/drivers/net/usb/ax88172a.c
> >> index 2e2081346740..e24773bb9398 100644
> >> --- a/drivers/net/usb/ax88172a.c
> >> +++ b/drivers/net/usb/ax88172a.c
> >> @@ -205,7 +205,8 @@ static int ax88172a_bind(struct usbnet *dev, struct usb_interface *intf)
> >>  		goto free;
> >>  	}
> >>  
> >> -	priv->phy_addr = asix_read_phy_addr(dev, priv->use_embdphy);
> >> +	ret = asix_read_phy_addr(dev, priv->use_embdphy);
> >> +	priv->phy_addr = ret;
> > 
> > Ah.. it is same bug in different color :)
> > You probably wonted to do:
> > 	if (ret < 0)
> > 		goto free;
> > 
> > 	priv->phy_addr = ret;
> 
> Doh, brain failure of mine. I'll send a V2 later today.
> 
> > 
> >>  	if (priv->phy_addr < 0) {
> >>  		ret = priv->phy_addr;
> >>  		goto free;
> >> -- 
> >> 2.31.1
> >>
> >>
> > 
> 
>
diff mbox series

Patch

diff --git a/drivers/net/usb/ax88172a.c b/drivers/net/usb/ax88172a.c
index 2e2081346740..e24773bb9398 100644
--- a/drivers/net/usb/ax88172a.c
+++ b/drivers/net/usb/ax88172a.c
@@ -205,7 +205,8 @@  static int ax88172a_bind(struct usbnet *dev, struct usb_interface *intf)
 		goto free;
 	}
 
-	priv->phy_addr = asix_read_phy_addr(dev, priv->use_embdphy);
+	ret = asix_read_phy_addr(dev, priv->use_embdphy);
+	priv->phy_addr = ret;
 	if (priv->phy_addr < 0) {
 		ret = priv->phy_addr;
 		goto free;