Wrong attribute lengths

[fakuivan]

APVs like Tunnel-Type are added to a packet using the function from_tagged_u32, which does not take into account the appropriate length of the attribute. Something similar happens with Tunnel-Medium-Type.

radius-rs/radius/src/core/rfc2868.rs

Lines 76 to 78 in 149e270

	pub fn add_tunnel_type(packet: &mut Packet, tag: Option<&Tag>, value: TunnelType) {
	packet.add(AVP::from_tagged_u32(TUNNEL_TYPE_TYPE, tag, value as u32));
	}

As mentioned in RFC2868, the length for Tunnel-Type is always 6, and this mismatch can cause problems with clients that strictly follow this. radtest will show attributes that do not follow these standards as Attr-N instead of decoding it into the appropriate name, so this can be useful when trying to detect these issues.

[part1cleth1ef]

Hey, sorry for the bump but is there any information on this??

[fakuivan]

Well, I did end up fixing this, but I didn't continue using radius and opted for something else instead, so I didn't follow up on it. I did a few changes but basically it seems like some attribute byte sizes were interpreted to be the same size as the integral type used, meaning if the value taken was u32, the attribute length would end up being 4 bytes. Since rust has no 3 byte integrals (no u24/i24) and some APVs are sized to 3 bytes, I ended up implementing a macro to trim the integral and panic on overflows.

Here are the changes I made: fakuivan@c226e30

Maybe you can make a PR out of this? I'm not aware of these issues being solved, maybe they are?

[elonen]

This is still an issue, and makes at least JunOS fail parsing the messages. Here's the workaround I ended up using:

// Causes 'MALFORMED DATA' on JunOS:

rfc2868::add_tunnel_type(&mut resp_packet, tag, rfc3580::TUNNEL_TYPE_VLAN);
rfc2868::add_tunnel_medium_type(&mut resp_packet, tag, rfc2868::TUNNEL_MEDIUM_TYPE_IEEE_802);


// Works:

fn u32_as_u24_str(v: u32) -> String {
    String::from_utf8(v.to_be_bytes()[1..].to_vec()).unwrap()
}

resp_packet.add(AVP::from_tagged_string(rfc2868::TUNNEL_TYPE_TYPE, tag, &u32_as_u24_str(rfc3580::TUNNEL_TYPE_VLAN)));
resp_packet.add(AVP::from_tagged_string(rfc2868::TUNNEL_MEDIUM_TYPE_TYPE, tag, &u32_as_u24_str(rfc2868::TUNNEL_MEDIUM_TYPE_IEEE_802)));