Bug #3914
closed
PAP PCO not handled correctly
Added by laforge about 5 years ago.
Updated almost 5 years ago.
Description
I don't have a GTP trace, but the attached Gb interface trace shows the following oddities:
- The PCO as sent by the MS/UE in the PDP CTX ACT REQ contains a PAP Auth Req
- This Auth Req is malformed according to the wireshark dissector (can we trust it?), but that's not the main point here
- The PCO as returned by the network to te MS doesn't contain any PAP Auth Resp
- not sure if support for PAP is required, but TS 24.008 at least states:
- At least the following protocol identifiers (as defined in RFC 3232 [103]) shall be
supported in this version of the protocol:C021H (LCP); C023H (PAP); C223H (CHAP);and 8021H (IPCP).
- Instead, our PCO response contains twice the PCO for IPCP (DNS servers), which clearly is wrong
Files
Note that the PAP inside the capture is clarly invalid as per specification. It sends a Peer-Id-Length of 04, but there's 6 (excluding NUL byte) or 7 (including NUL byte) characters of Peer Identifier.
Nevertheless, OsmoGGSN should handle this somewhat intelligently, e.g. by sending an ACK in return.
Under no circumstances should OsmoGGSN send duplicate DNS PCOs
- Status changed from New to In Progress
- % Done changed from 0 to 30
Note that the PAP inside the capture is clarly invalid as per specification. It sends a Peer-Id-Length of 04, but there's 6 (excluding NUL byte) or 7 (including NUL byte) characters of Peer Identifier.
Nevertheless, OsmoGGSN should handle this somewhat intelligently, e.g. by sending an ACK in return.
Under no circumstances should OsmoGGSN send duplicate DNS PCOs
See https://gerrit.osmocom.org/#/c/osmo-ttcn3-hacks/+/13563 for improving our TTCN3 tests to avoid duplicate PCO protocolIDs and https://gerrit.osmocom.org/#/c/osmo-ttcn3-hacks/+/13564 for a test case reproducing exactly the PCOs as observed by that phone.
- % Done changed from 30 to 60
- % Done changed from 60 to 90
I can take over this one and finishing polishing the patch if you want.
On Wed, Jun 26, 2019 at 12:57:33PM +0000, pespin [REDMINE] wrote:
I can take over this one and finishing polishing the patch if you want.
Hi Pau, if it is relatively quick to resolve: Thanks. Particularly during my holidays
I wouldn't expect me to find time for anything but the most urgent isuses :/
- Assignee changed from laforge to pespin
- Status changed from In Progress to Feedback
ggsn patches merged, osmo-ttcn3 hacks still in gerrit waiting for review. Once merged ticket can be closed.
- Status changed from Feedback to Resolved
- % Done changed from 90 to 100
Thanks a lot for working on this!
With the recent OsmoGGSN I've finally managed to 'attach' my POS terminal that I had with me at OsmoDevCon 2018. What I find funny is that I already tried to make OsmoGGSN send PAP Auth ACK before, but I didn't work. My implementation was missing the welcome text , and this seems to be the key.
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