[PATCH] net: dsa: mt7530: Add some return-value checks

[PATCH] net: dsa: mt7530: Add some return-value checks

[Alex Dewar]

In mt7531_cpu_port_config(), if the variable port is neither 5 nor 5,
then variable interface will be used uninitialised. Change the function
to return -EINVAL in this case.

As the return value of mt7531_cpu_port_config() is never checked
(even though it returns an int) add a check in the correct place so that
the error can be passed up the call stack. Now that we correctly handle
errors thrown in this function, also check the return value of
mt7531_mac_config() in case an error occurs here.

Addresses-Coverity: 1496993 ("Uninitialized variables")
Fixes: c288575f7810 ("net: dsa: mt7530: Add the support of MT7531 switch")
Signed-off-by: Alex Dewar <alex.dewar90@gmail.com>
---

If it is not expected that these functions will throw errors (i.e.
because the parameters passed will always be correct), we could dispense
with the use of EINVAL errors and just use BUG*() macros instead. Let me
know if you'd rather I fix things up in that way.

Best,
Alex

 drivers/net/dsa/mt7530.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index 61388945d316..157d0a01faae 100644
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -945,10 +945,14 @@ static int
 mt753x_cpu_port_enable(struct dsa_switch *ds, int port)
 {
 	struct mt7530_priv *priv = ds->priv;
+	int ret;
 
 	/* Setup max capability of CPU port at first */
-	if (priv->info->cpu_port_config)
-		priv->info->cpu_port_config(ds, port);
+	if (priv->info->cpu_port_config) {
+		ret = priv->info->cpu_port_config(ds, port);
+		if (ret)
+			return ret;
+	}
 
 	/* Enable Mediatek header mode on the cpu port */
 	mt7530_write(priv, MT7530_PVC_P(port),
@@ -2275,7 +2279,7 @@ mt7531_cpu_port_config(struct dsa_switch *ds, int port)
 {
 	struct mt7530_priv *priv = ds->priv;
 	phy_interface_t interface;
-	int speed;
+	int ret, speed;
 
 	switch (port) {
 	case 5:
@@ -2293,6 +2297,8 @@ mt7531_cpu_port_config(struct dsa_switch *ds, int port)
 
 		priv->p6_interface = interface;
 		break;
+	default:
+		return -EINVAL;
 	}
 
 	if (interface == PHY_INTERFACE_MODE_2500BASEX)
@@ -2300,7 +2306,9 @@ mt7531_cpu_port_config(struct dsa_switch *ds, int port)
 	else
 		speed = SPEED_1000;
 
-	mt7531_mac_config(ds, port, MLO_AN_FIXED, interface);
+	ret = mt7531_mac_config(ds, port, MLO_AN_FIXED, interface);
+	if (ret)
+		return ret;
 	mt7530_write(priv, MT7530_PMCR_P(port),
 		     PMCR_CPU_PORT_SETTING(priv->id));
 	mt753x_phylink_mac_link_up(ds, port, MLO_AN_FIXED, interface, NULL,
-- 
2.28.0

Re: [PATCH] net: dsa: mt7530: Add some return-value checks

[Gustavo A. R. Silva]

On 9/16/20 14:50, Alex Dewar wrote:

[..]

> 
>  drivers/net/dsa/mt7530.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
> 

[..]

>  
>  	/* Enable Mediatek header mode on the cpu port */
>  	mt7530_write(priv, MT7530_PVC_P(port),
> @@ -2275,7 +2279,7 @@ mt7531_cpu_port_config(struct dsa_switch *ds, int port)
>  {
>  	struct mt7530_priv *priv = ds->priv;
>  	phy_interface_t interface;
> -	int speed;
> +	int ret, speed;

Don't do this. Instead, declare each variable on its own line. In this case,
speed before ret.

Thanks
--
Gustavo

Re: [PATCH] net: dsa: mt7530: Add some return-value checks

[Alex Dewar]

[snip] 
> >  
> >  	/* Enable Mediatek header mode on the cpu port */
> >  	mt7530_write(priv, MT7530_PVC_P(port),
> > @@ -2275,7 +2279,7 @@ mt7531_cpu_port_config(struct dsa_switch *ds, int port)
> >  {
> >  	struct mt7530_priv *priv = ds->priv;
> >  	phy_interface_t interface;
> > -	int speed;
> > +	int ret, speed;
> 
> Don't do this. Instead, declare each variable on its own line. In this case,
> speed before ret.

Good point. I'll do this in v2 :-)
> 
> Thanks
> --
> Gustavo

Re: [PATCH] net: dsa: mt7530: Add some return-value checks

[Alex Dewar]

On Wed, Sep 16, 2020 at 08:50:17PM +0100, Alex Dewar wrote:
> In mt7531_cpu_port_config(), if the variable port is neither 5 nor 5,

This should read "neither 5 nor 6", obviously. I'll fix in v2.
 

Re: [PATCH] net: dsa: mt7530: Add some return-value checks

[Landen Chao]

Hi Alex,

Thanks for your review and fixing.
On Thu, 2020-09-17 at 03:50 +0800, Alex Dewar wrote:
[..]
> 
> If it is not expected that these functions will throw errors (i.e.
> because the parameters passed will always be correct), we could dispense
> with the use of EINVAL errors and just use BUG*() macros instead. Let me
> know if you'd rather I fix things up in that way.
The cpu port setting is passed by dts. Use EINVAL to catch unexpected
setting is fine.
> 
> Best,
> Alex
> 
>  drivers/net/dsa/mt7530.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
> index 61388945d316..157d0a01faae 100644
> --- a/drivers/net/dsa/mt7530.c
> +++ b/drivers/net/dsa/mt7530.c
> @@ -945,10 +945,14 @@ static int
>  mt753x_cpu_port_enable(struct dsa_switch *ds, int port)
>  {
>  	struct mt7530_priv *priv = ds->priv;
> +	int ret;
>  
>  	/* Setup max capability of CPU port at first */
> -	if (priv->info->cpu_port_config)
> -		priv->info->cpu_port_config(ds, port);
> +	if (priv->info->cpu_port_config) {
> +		ret = priv->info->cpu_port_config(ds, port);
> +		if (ret)
> +			return ret;
> +	}
How about check return value in caller function, mt7530_setup() and
mt7531_setup(), too?
                if (dsa_is_cpu_port(ds, i)) {
                        ret = mt753x_cpu_port_enable(ds, i);
			if (ret)
				return ret;
		} else {
[..]
regards,
landen

[PATCH v2] net: dsa: mt7530: Add some return-value checks

[Alex Dewar]

In mt7531_cpu_port_config(), if the variable port is neither 5 nor 6,
then variable interface will be used uninitialised. Change the function
to return -EINVAL in this case.

As the return value of mt7531_cpu_port_config() is never checked
(even though it returns an int) add a check in the correct place so that
the error can be passed up the call stack. Now that we correctly handle
errors thrown in this function, also check the return value of
mt7531_mac_config() in case an error occurs here. Also add misisng
checks to mt7530_setup() and mt7531_setup(), which are another level
further up the call stack.

Fixes: c288575f7810 ("net: dsa: mt7530: Add the support of MT7531 switch")
Addresses-Coverity: 1496993 ("Uninitialized variables")
Signed-off-by: Alex Dewar <alex.dewar90@gmail.com>
---
v2:
	- fix typo in commit message
	- split variable declarations onto multiple lines (Gustavo)
	- add additional checks for mt753*_setup (Landen)

 drivers/net/dsa/mt7530.c | 31 ++++++++++++++++++++++---------
 1 file changed, 22 insertions(+), 9 deletions(-)

diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index 61388945d316..cb3efa7de7a8 100644
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -945,10 +945,14 @@ static int
 mt753x_cpu_port_enable(struct dsa_switch *ds, int port)
 {
 	struct mt7530_priv *priv = ds->priv;
+	int ret;
 
 	/* Setup max capability of CPU port at first */
-	if (priv->info->cpu_port_config)
-		priv->info->cpu_port_config(ds, port);
+	if (priv->info->cpu_port_config) {
+		ret = priv->info->cpu_port_config(ds, port);
+		if (ret)
+			return ret;
+	}
 
 	/* Enable Mediatek header mode on the cpu port */
 	mt7530_write(priv, MT7530_PVC_P(port),
@@ -1631,9 +1635,11 @@ mt7530_setup(struct dsa_switch *ds)
 		mt7530_rmw(priv, MT7530_PCR_P(i), PCR_MATRIX_MASK,
 			   PCR_MATRIX_CLR);
 
-		if (dsa_is_cpu_port(ds, i))
-			mt753x_cpu_port_enable(ds, i);
-		else
+		if (dsa_is_cpu_port(ds, i)) {
+			ret = mt753x_cpu_port_enable(ds, i);
+			if (ret)
+				return ret;
+		} else
 			mt7530_port_disable(ds, i);
 
 		/* Enable consistent egress tag */
@@ -1785,9 +1791,11 @@ mt7531_setup(struct dsa_switch *ds)
 
 		mt7530_set(priv, MT7531_DBG_CNT(i), MT7531_DIS_CLR);
 
-		if (dsa_is_cpu_port(ds, i))
-			mt753x_cpu_port_enable(ds, i);
-		else
+		if (dsa_is_cpu_port(ds, i)) {
+			ret = mt753x_cpu_port_enable(ds, i);
+			if (ret)
+				return ret;
+		} else
 			mt7530_port_disable(ds, i);
 
 		/* Enable consistent egress tag */
@@ -2276,6 +2284,7 @@ mt7531_cpu_port_config(struct dsa_switch *ds, int port)
 	struct mt7530_priv *priv = ds->priv;
 	phy_interface_t interface;
 	int speed;
+	int ret;
 
 	switch (port) {
 	case 5:
@@ -2293,6 +2302,8 @@ mt7531_cpu_port_config(struct dsa_switch *ds, int port)
 
 		priv->p6_interface = interface;
 		break;
+	default:
+		return -EINVAL;
 	}
 
 	if (interface == PHY_INTERFACE_MODE_2500BASEX)
@@ -2300,7 +2311,9 @@ mt7531_cpu_port_config(struct dsa_switch *ds, int port)
 	else
 		speed = SPEED_1000;
 
-	mt7531_mac_config(ds, port, MLO_AN_FIXED, interface);
+	ret = mt7531_mac_config(ds, port, MLO_AN_FIXED, interface);
+	if (ret)
+		return ret;
 	mt7530_write(priv, MT7530_PMCR_P(port),
 		     PMCR_CPU_PORT_SETTING(priv->id));
 	mt753x_phylink_mac_link_up(ds, port, MLO_AN_FIXED, interface, NULL,
-- 
2.28.0

Re: [PATCH v2] net: dsa: mt7530: Add some return-value checks

[Landen Chao]

Hi Alex,

Thanks for your patch. By linux/scripts/checkpatch.pl

On Sun, 2020-09-20 at 03:28 +0800, Alex Dewar wrote:
[..]
> @@ -1631,9 +1635,11 @@ mt7530_setup(struct dsa_switch *ds)
>  		mt7530_rmw(priv, MT7530_PCR_P(i), PCR_MATRIX_MASK,
>  			   PCR_MATRIX_CLR);
>  
> -		if (dsa_is_cpu_port(ds, i))
> -			mt753x_cpu_port_enable(ds, i);
> -		else
> +		if (dsa_is_cpu_port(ds, i)) {
> +			ret = mt753x_cpu_port_enable(ds, i);
> +			if (ret)
> +				return ret;
> +		} else
>  			mt7530_port_disable(ds, i);
CHECK: braces {} should be used on all arms of this statement
CHECK: Unbalanced braces around else statement
>  
>  		/* Enable consistent egress tag */
> @@ -1785,9 +1791,11 @@ mt7531_setup(struct dsa_switch *ds)
>  
>  		mt7530_set(priv, MT7531_DBG_CNT(i), MT7531_DIS_CLR);
>  
> -		if (dsa_is_cpu_port(ds, i))
> -			mt753x_cpu_port_enable(ds, i);
> -		else
> +		if (dsa_is_cpu_port(ds, i)) {
> +			ret = mt753x_cpu_port_enable(ds, i);
> +			if (ret)
> +				return ret;
> +		} else
>  			mt7530_port_disable(ds, i);
CHECK: braces {} should be used on all arms of this statement
CHECK: Unbalanced braces around else statement

[..]
regards landen

Re: [PATCH v2] net: dsa: mt7530: Add some return-value checks

[Alex Dewar]

On 2020-09-24 13:13, Landen Chao wrote:
> Hi Alex,
>
> Thanks for your patch. By linux/scripts/checkpatch.pl
>
> On Sun, 2020-09-20 at 03:28 +0800, Alex Dewar wrote:
> [..]
>> @@ -1631,9 +1635,11 @@ mt7530_setup(struct dsa_switch *ds)
>>   		mt7530_rmw(priv, MT7530_PCR_P(i), PCR_MATRIX_MASK,
>>   			   PCR_MATRIX_CLR);
>>   
>> -		if (dsa_is_cpu_port(ds, i))
>> -			mt753x_cpu_port_enable(ds, i);
>> -		else
>> +		if (dsa_is_cpu_port(ds, i)) {
>> +			ret = mt753x_cpu_port_enable(ds, i);
>> +			if (ret)
>> +				return ret;
>> +		} else
>>   			mt7530_port_disable(ds, i);
> CHECK: braces {} should be used on all arms of this statement
> CHECK: Unbalanced braces around else statement
>>   
>>   		/* Enable consistent egress tag */
>> @@ -1785,9 +1791,11 @@ mt7531_setup(struct dsa_switch *ds)
>>   
>>   		mt7530_set(priv, MT7531_DBG_CNT(i), MT7531_DIS_CLR);
>>   
>> -		if (dsa_is_cpu_port(ds, i))
>> -			mt753x_cpu_port_enable(ds, i);
>> -		else
>> +		if (dsa_is_cpu_port(ds, i)) {
>> +			ret = mt753x_cpu_port_enable(ds, i);
>> +			if (ret)
>> +				return ret;
>> +		} else
>>   			mt7530_port_disable(ds, i);
> CHECK: braces {} should be used on all arms of this statement
> CHECK: Unbalanced braces around else statement
>
> [..]
> regards landen
Hi Landen,

Sorry about this... I usually run checkpatch over my patches. Would you 
like me to send a separate fix or a v3?

Best,
Alex

Re: [PATCH v2] net: dsa: mt7530: Add some return-value checks

[Landen Chao]

On Thu, 2020-09-24 at 14:11 +0100, Alex Dewar wrote:
> On 2020-09-24 13:13, Landen Chao wrote:
> > Hi Alex,
> >
> > Thanks for your patch. By linux/scripts/checkpatch.pl
> >
> > On Sun, 2020-09-20 at 03:28 +0800, Alex Dewar wrote:
> > [..]
> >> @@ -1631,9 +1635,11 @@ mt7530_setup(struct dsa_switch *ds)
> >>   		mt7530_rmw(priv, MT7530_PCR_P(i), PCR_MATRIX_MASK,
> >>   			   PCR_MATRIX_CLR);
> >>   
> >> -		if (dsa_is_cpu_port(ds, i))
> >> -			mt753x_cpu_port_enable(ds, i);
> >> -		else
> >> +		if (dsa_is_cpu_port(ds, i)) {
> >> +			ret = mt753x_cpu_port_enable(ds, i);
> >> +			if (ret)
> >> +				return ret;
> >> +		} else
> >>   			mt7530_port_disable(ds, i);
> > CHECK: braces {} should be used on all arms of this statement
> > CHECK: Unbalanced braces around else statement
> >>   
> >>   		/* Enable consistent egress tag */
> >> @@ -1785,9 +1791,11 @@ mt7531_setup(struct dsa_switch *ds)
> >>   
> >>   		mt7530_set(priv, MT7531_DBG_CNT(i), MT7531_DIS_CLR);
> >>   
> >> -		if (dsa_is_cpu_port(ds, i))
> >> -			mt753x_cpu_port_enable(ds, i);
> >> -		else
> >> +		if (dsa_is_cpu_port(ds, i)) {
> >> +			ret = mt753x_cpu_port_enable(ds, i);
> >> +			if (ret)
> >> +				return ret;
> >> +		} else
> >>   			mt7530_port_disable(ds, i);
> > CHECK: braces {} should be used on all arms of this statement
> > CHECK: Unbalanced braces around else statement
> >
> > [..]
> > regards landen
> Hi Landen,
> 
> Sorry about this... I usually run checkpatch over my patches. Would you 
> like me to send a separate fix or a v3?
> 
> Best,
> Alex
Hi Alex,

Because v2 has not been merged yet, could you help to fix it in v3?

regards landen

[PATCH v3] net: dsa: mt7530: Add some return-value checks

[Alex Dewar]

In mt7531_cpu_port_config(), if the variable port is neither 5 nor 6,
then variable interface will be used uninitialised. Change the function
to return -EINVAL in this case.

As the return value of mt7531_cpu_port_config() is never checked
(even though it returns an int) add a check in the correct place so that
the error can be passed up the call stack. Now that we correctly handle
errors thrown in this function, also check the return value of
mt7531_mac_config() in case an error occurs here. Also add misisng
checks to mt7530_setup() and mt7531_setup(), which are another level
further up the call stack.

Fixes: c288575f7810 ("net: dsa: mt7530: Add the support of MT7531 switch")
Addresses-Coverity: 1496993 ("Uninitialized variables")
Signed-off-by: Alex Dewar <alex.dewar90@gmail.com>
---

Hi Landen,

Here you go!

v3:
	- fix checkpatch warning about braces (Landen)
v2:
	- fix typo in commit message
	- split variable declarations onto multiple lines (Gustavo)
	- add additional checks for mt753*_setup (Landen)

 drivers/net/dsa/mt7530.c | 33 ++++++++++++++++++++++++---------
 1 file changed, 24 insertions(+), 9 deletions(-)

diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index 61388945d316..23b2386318b2 100644
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -945,10 +945,14 @@ static int
 mt753x_cpu_port_enable(struct dsa_switch *ds, int port)
 {
 	struct mt7530_priv *priv = ds->priv;
+	int ret;
 
 	/* Setup max capability of CPU port at first */
-	if (priv->info->cpu_port_config)
-		priv->info->cpu_port_config(ds, port);
+	if (priv->info->cpu_port_config) {
+		ret = priv->info->cpu_port_config(ds, port);
+		if (ret)
+			return ret;
+	}
 
 	/* Enable Mediatek header mode on the cpu port */
 	mt7530_write(priv, MT7530_PVC_P(port),
@@ -1631,10 +1635,13 @@ mt7530_setup(struct dsa_switch *ds)
 		mt7530_rmw(priv, MT7530_PCR_P(i), PCR_MATRIX_MASK,
 			   PCR_MATRIX_CLR);
 
-		if (dsa_is_cpu_port(ds, i))
-			mt753x_cpu_port_enable(ds, i);
-		else
+		if (dsa_is_cpu_port(ds, i)) {
+			ret = mt753x_cpu_port_enable(ds, i);
+			if (ret)
+				return ret;
+		} else {
 			mt7530_port_disable(ds, i);
+		}
 
 		/* Enable consistent egress tag */
 		mt7530_rmw(priv, MT7530_PVC_P(i), PVC_EG_TAG_MASK,
@@ -1785,10 +1792,13 @@ mt7531_setup(struct dsa_switch *ds)
 
 		mt7530_set(priv, MT7531_DBG_CNT(i), MT7531_DIS_CLR);
 
-		if (dsa_is_cpu_port(ds, i))
-			mt753x_cpu_port_enable(ds, i);
-		else
+		if (dsa_is_cpu_port(ds, i)) {
+			ret = mt753x_cpu_port_enable(ds, i);
+			if (ret)
+				return ret;
+		} else {
 			mt7530_port_disable(ds, i);
+		}
 
 		/* Enable consistent egress tag */
 		mt7530_rmw(priv, MT7530_PVC_P(i), PVC_EG_TAG_MASK,
@@ -2276,6 +2286,7 @@ mt7531_cpu_port_config(struct dsa_switch *ds, int port)
 	struct mt7530_priv *priv = ds->priv;
 	phy_interface_t interface;
 	int speed;
+	int ret;
 
 	switch (port) {
 	case 5:
@@ -2293,6 +2304,8 @@ mt7531_cpu_port_config(struct dsa_switch *ds, int port)
 
 		priv->p6_interface = interface;
 		break;
+	default:
+		return -EINVAL;
 	}
 
 	if (interface == PHY_INTERFACE_MODE_2500BASEX)
@@ -2300,7 +2313,9 @@ mt7531_cpu_port_config(struct dsa_switch *ds, int port)
 	else
 		speed = SPEED_1000;
 
-	mt7531_mac_config(ds, port, MLO_AN_FIXED, interface);
+	ret = mt7531_mac_config(ds, port, MLO_AN_FIXED, interface);
+	if (ret)
+		return ret;
 	mt7530_write(priv, MT7530_PMCR_P(port),
 		     PMCR_CPU_PORT_SETTING(priv->id));
 	mt753x_phylink_mac_link_up(ds, port, MLO_AN_FIXED, interface, NULL,
-- 
2.28.0