[PATCH net] bareudp: Disallow udp port 0.

[PATCH net] bareudp: Disallow udp port 0.

[Martin Varghese]

From: Martin Varghese <martin.varghese@nokia.com>

Kernel does not support udp destination port 0 on wire. Hence
bareudp device with udp destination port 0 must be disallowed.

Fixes: 571912c69f0e ("net: UDP tunnel encapsulation module for tunnelling different protocols like MPLS, IP, NSH etc.")
Signed-off-by: Martin Varghese <martin.varghese@nokia.com>
---
 drivers/net/bareudp.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/net/bareudp.c b/drivers/net/bareudp.c
index 88e7900853db..08b195d32cbe 100644
--- a/drivers/net/bareudp.c
+++ b/drivers/net/bareudp.c
@@ -578,8 +578,13 @@ static int bareudp2info(struct nlattr *data[], struct bareudp_conf *conf,
 		return -EINVAL;
 	}
 
-	if (data[IFLA_BAREUDP_PORT])
+	if (data[IFLA_BAREUDP_PORT]) {
 		conf->port =  nla_get_u16(data[IFLA_BAREUDP_PORT]);
+		if (!conf->port) {
+			NL_SET_ERR_MSG(extack, "udp port 0 not supported");
+			return -EINVAL;
+		}
+	}
 
 	if (data[IFLA_BAREUDP_ETHERTYPE])
 		conf->ethertype =  nla_get_u16(data[IFLA_BAREUDP_ETHERTYPE]);
-- 
2.18.4

Re: [PATCH net] bareudp: Disallow udp port 0.

[Jakub Kicinski]

On Thu, 30 Jul 2020 22:33:51 +0530 Martin Varghese wrote:
> From: Martin Varghese <martin.varghese@nokia.com>
> 
> Kernel does not support udp destination port 0 on wire. Hence
> bareudp device with udp destination port 0 must be disallowed.
> 
> Fixes: 571912c69f0e ("net: UDP tunnel encapsulation module for tunnelling different protocols like MPLS, IP, NSH etc.")
> Signed-off-by: Martin Varghese <martin.varghese@nokia.com>
> ---
>  drivers/net/bareudp.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/bareudp.c b/drivers/net/bareudp.c
> index 88e7900853db..08b195d32cbe 100644
> --- a/drivers/net/bareudp.c
> +++ b/drivers/net/bareudp.c
> @@ -578,8 +578,13 @@ static int bareudp2info(struct nlattr *data[], struct bareudp_conf *conf,
>  		return -EINVAL;
>  	}
>  
> -	if (data[IFLA_BAREUDP_PORT])
> +	if (data[IFLA_BAREUDP_PORT]) {
>  		conf->port =  nla_get_u16(data[IFLA_BAREUDP_PORT]);
> +		if (!conf->port) {
> +			NL_SET_ERR_MSG(extack, "udp port 0 not supported");
> +			return -EINVAL;
> +		}
> +	}

Please use one of the NLA_POLICY_**-ies, probably NLA_POLICY_MIN() ? 
That's better for documenting, exporting for user space, and will also
point the user space to the attribute in exack automatically.

Re: [PATCH net] bareudp: Disallow udp port 0.

[Martin Varghese]

On Thu, Jul 30, 2020 at 04:20:30PM -0700, Jakub Kicinski wrote:
> On Thu, 30 Jul 2020 22:33:51 +0530 Martin Varghese wrote:
> > From: Martin Varghese <martin.varghese@nokia.com>
> > 
> > Kernel does not support udp destination port 0 on wire. Hence
> > bareudp device with udp destination port 0 must be disallowed.
> > 
> > Fixes: 571912c69f0e ("net: UDP tunnel encapsulation module for tunnelling different protocols like MPLS, IP, NSH etc.")
> > Signed-off-by: Martin Varghese <martin.varghese@nokia.com>
> > ---
> >  drivers/net/bareudp.c | 7 ++++++-
> >  1 file changed, 6 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/net/bareudp.c b/drivers/net/bareudp.c
> > index 88e7900853db..08b195d32cbe 100644
> > --- a/drivers/net/bareudp.c
> > +++ b/drivers/net/bareudp.c
> > @@ -578,8 +578,13 @@ static int bareudp2info(struct nlattr *data[], struct bareudp_conf *conf,
> >  		return -EINVAL;
> >  	}
> >  
> > -	if (data[IFLA_BAREUDP_PORT])
> > +	if (data[IFLA_BAREUDP_PORT]) {
> >  		conf->port =  nla_get_u16(data[IFLA_BAREUDP_PORT]);
> > +		if (!conf->port) {
> > +			NL_SET_ERR_MSG(extack, "udp port 0 not supported");
> > +			return -EINVAL;
> > +		}
> > +	}
> 
> Please use one of the NLA_POLICY_**-ies, probably NLA_POLICY_MIN() ? 
> That's better for documenting, exporting for user space, and will also
> point the user space to the attribute in exack automatically.

Ok, I will check how to do this way. Thanks for the feedback.

Regards,
Martin