How is User-Name getting into reply?

18 Nov 2016

      I don't understand how a User-Name attribute is being added into the 
*reply* when using EAP.

To replicate this, I have the default 3.0.12 config with the "steve" 
user uncommented, and with radtest it behaves as expected: no User-Name 
in the reply.

But if I exercise this account using eapol_test, I see the outer 
User-Name attribute is in the Access-Accept:

(29) Sent Access-Accept Id 10 from 127.0.0.1:1812 to 127.0.0.1:38985 
length 0
(29)   MS-MPPE-Recv-Key = 
0xb581e1ac47471ad3952989c90595a23d8b851827abebc4089ef09574e9d69246
(29)   MS-MPPE-Send-Key = 
0x244f2954e441937015fa8aa44a36fc94d3c473fbb86ae9498b93f3524b126d37
(29)   EAP-Message = 0x030a0004
(29)   Message-Authenticator = 0x00000000000000000000000000000000
(29)   User-Name = "anonymous"    << HERE

And if I uncomment these sections from inner-tunnel:

         update {
                 &outer.session-state: += &reply:
         }

         update outer.session-state {
                 MS-MPPE-Encryption-Policy !* ANY
                 MS-MPPE-Encryption-Types !* ANY
                 MS-MPPE-Send-Key !* ANY
                 MS-MPPE-Recv-Key !* ANY
                 Message-Authenticator !* ANY
                 EAP-Message !* ANY
                 Proxy-State !* ANY
         }

then the reply has *two* User-Name attributes:

(10) Sent Access-Accept Id 10 from 127.0.0.1:1812 to 127.0.0.1:53750 
length 0
(10)   MS-MPPE-Recv-Key = 
0x0bd13ceb1f41f1cd7acbc81339d64f6a5411d5c507153eacefe6f7b51201956c
(10)   MS-MPPE-Send-Key = 
0x619ca77357791b4b88a270e610dd8716cce3faebd7973dc07b18aa2cb625611a
(10)   EAP-Message = 0x030a0004
(10)   Message-Authenticator = 0x00000000000000000000000000000000
(10)   User-Name = "anonymous"    << HERE
(10)   Service-Type += Framed-User
(10)   Framed-Protocol += PPP
(10)   Framed-IP-Address += 172.16.3.33
(10)   Framed-IP-Netmask += 255.255.255.0
(10)   Framed-Routing += Broadcast-Listen
(10)   Framed-Filter-Id += "std.ppp"
(10)   Framed-MTU += 1500
(10)   Framed-Compression += Van-Jacobson-TCP-IP
(10)   User-Name += "steve"    << HERE

Any clues as to what's going on here?

RFC2865 (section 5.44) says that an Access-Accept may only contain 0 or 
1 User-Name attributes. I could filter them both out, but I'd like to 
understand how they are getting there in the first place.

Thanks,

Brian.

How is User-Name getting into reply?

Brian Candler