[sr-dev] Syntax error

Scherney Theodor Theodor.Scherney at kontron.com
Tue Sep 28 14:54:30 CEST 2021


Hello,

To be accurate: I am going to implement this change and would like to know, if the PR would be accepted by the community.

BR
Theo

Von: sr-dev <sr-dev-bounces at lists.kamailio.org> Im Auftrag von Scherney Theodor
Gesendet: Mittwoch, 22. September 2021 09:24
An: 'sr-dev at lists.kamailio.org' <sr-dev at lists.kamailio.org>
Cc: Onic Roman <Roman.Onic at kontron.com>; Valentin Christoph <Christoph.Valentin at kontron.com>
Betreff: [sr-dev] Syntax error

Hello,

I have tested following scenario:

Alice "calls" Bob. Call is established.
At the end of the call, Bob disconnects (hangs up) first and generates a BYE message.

If there is a syntax error in FROM Header of BYE message, a  400 “Bad From header” is responded by the Proxy.

If there is a syntax error in TO Header of BYE message, the message is discarded.
According RFC 3261 this is not correct.

Is it okay, to implement the same logic for TO Header as done for FROM Header?


RFC 3261:

16.2 Stateful Proxy

……….

For all new requests, including any with unknown methods, an element  intending to proxy the request MUST:
      1. Validate the request (Section 16.3)
      2. Preprocess routing information (Section 16.4)
      3. Determine target(s) for the request (Section 16.5)
            +--------------------+
            |                    | +---+
            |                    | | C |
            |                    | | T |
            |                    | +---+
      +---+ |       Proxy        | +---+   CT = Client Transaction
      | S | |  "Higher" Layer    | | C |
      | T | |                    | | T |   ST = Server Transaction
      +---+ |                    | +---+
            |                    | +---+
            |                    | | C |
            |                    | | T |
            |                    | +---+
            +--------------------+
               Figure 3: Stateful Proxy Model

      4. Forward the request to each target (Section 16.6)
      5. Process all responses (Section 16.7)

16.3 Request Validation

   Before an element can proxy a request, it MUST verify the message’s  validity.
   A valid message must pass the following checks:

      1. Reasonable Syntax
      2. URI scheme
      3. Max-Forwards
      4. (Optional) Loop Detection
      5. Proxy-Require
      6. Proxy-Authorization

   If any of these checks fail, the element MUST behave as a user agent server (see Section 8.2) and respond with an error code.


LOGs:

BYE with syntax error in  FROM header:

Sep 21 16:44:51 vict2-ims3 /usr/sbin/kamailio[12723]: [logSDID at 20306 resource="core"] ERROR: <core> [core/parser/parse_addr_spec.c:555]: parse_to_param(): unexpected end of header, status 20: [;transport=UDP;tag=b3af-8e5a-1e36-79340f18;#015] .
Sep 21 16:44:51 vict2-ims3 /usr/sbin/kamailio[12723]: [logSDID at 20306 resource="core"] ERROR: <core> [core/parser/parse_addr_spec.c:881]: parse_addr_spec(): invalid To -  unexpected end of header in state 11
Sep 21 16:44:51 vict2-ims3 /usr/sbin/kamailio[12723]: [logSDID at 20306 resource="core"] ERROR: <core> [core/parser/parse_from.c:75]: parse_from_header(): bad From header [sip:catt180 at vict-ims.net;transport=UDP;tag=b3af-8e5a-1e36-79340f18;]
Sep 21 16:44:51 vict2-ims3 /usr/sbin/kamailio[12723]: [logSDID at 20306 resource="pv"] ERROR: pv [pv_core.c:468]: pv_get_from_attr(): cannot parse From header
Sep 21 16:44:51 vict2-ims3 /usr/sbin/kamailio[12723]: [logSDID at 20306 resource="xlog"] INFO: <script>: route BYE (<null> (193.154.113.40:5065) to sip:catt181 at vict-ims.net, 1632235417904catt180, )
Sep 21 16:44:51 vict2-ims3 /usr/sbin/kamailio[12723]: [logSDID at 20306 resource="xlog"] INFO: <script>: BYE (BYE sip:catt181 at 193.154.113.40:5065;transport=UDP;rinstance=317-catt181 SIP/2.0#015#012From: sip:catt180 at vict-ims.net;transport=UDP;tag=b3af-8e5a-1e36-79340f18;#015#012To: sip:catt181 at vict-ims.net;transport=UDP;tag=9d7b-d1c6-c06b-7a1dbec7#015#012Call-ID: 1632235417904catt180#015#012CSeq: 2 BYE#015#012Contact: sip:catt180 at 193.154.113.40:5065;transport=UDP;rinstance=317-catt180#015#012Content-Length: 0#015#012Max-Forwards: 70#015#012Route: sip:mo at 172.29.21.60;r2=on;lr;ftag=b3af-8e5a-1e36-79340f18;rm=8;did=8ed.6e12#015#012Route: sip:mo at pcscf-1.vict-ims.net:5060;r2=on;lr;ftag=b3af-8e5a-1e36-79340f18;rm=8;did=8ed.6e12#015#012Route: sip:mo at vict-ims.net;lr;ftag=b3af-8e5a-1e36-79340f18;did=8ed.e7b1#015#012Route: sip:mt at vict-ims.net;lr;ftag=b3af-8e5a-1e36-79340f18;did=8ed.e7b1#015#012Route: sip:mt at pcscf-1.vict-ims.net;r2=on;lr;ftag=b3af-8e5a-1e36-79340f18;rm=7;did=8ed.7e12#015#012Route: sip:mt at 172.29.21.60:5060;r2=on;lr;ftag=b3af-8e5a-1e36-79340f18;rm=7;did=8ed.7e12#015#012Via: SIP/2.0/UDP 193.154.113.40:5065;branch=z9hG4bKf7057b36-0#015#012#015#012)
Sep 21 16:44:51 vict2-ims3 /usr/sbin/kamailio[12723]: [logSDID at 20306 resource="core"] ERROR: <core> [core/parser/parse_addr_spec.c:555]: parse_to_param(): unexpected end of header, status 20: [;transport=UDP;tag=b3af-8e5a-1e36-79340f18;#015] .
Sep 21 16:44:51 vict2-ims3 /usr/sbin/kamailio[12723]: [logSDID at 20306 resource="core"] ERROR: <core> [core/parser/parse_addr_spec.c:881]: parse_addr_spec(): invalid To -  unexpected end of header in state 11
Sep 21 16:44:51 vict2-ims3 /usr/sbin/kamailio[12723]: [logSDID at 20306 resource="sanity"] WARNING: sanity [sanity.c:776]: check_parse_uris(): failed to parse From header [sip:catt180 at vict-ims.net;transport=UDP;tag=b3af-8e5a-1e36-79340f18;]
Sep 21 16:44:51 vict2-ims3 /usr/sbin/kamailio[12723]: [logSDID at 20306 resource="xlog"] INFO: <script>: t_relay_send_reply_sl - BYE (SIP/2.0 400 Bad From header#015#012From: sip:catt180 at vict-ims.net;transport=UDP;tag=b3af-8e5a-1e36-79340f18;#015#012To: sip:catt181 at vict-ims.net;transport=UDP;tag=9d7b-d1c6-c06b-7a1dbec7#015#012Call-ID: 1632235417904catt180#015#012CSeq: 2 BYE#015#012Via: SIP/2.0/UDP 193.154.113.40:5065;branch=z9hG4bKf7057b36-0#015#012Server: Kamailio P-CSCF#015#012Content-Length: 0#015#012#015#012)


BYE with syntax error in TO header:

Sep 21 16:41:07 vict2-ims3 /usr/sbin/kamailio[12733]: [logSDID at 20306 resource="core"] ERROR: <core> [core/parser/parse_addr_spec.c:555]: parse_to_param(): unexpected end of header, status 20: [;transport=UDP;tag=1ba4-ff0c-82af-415174d1;#015#012] .
Sep 21 16:41:07 vict2-ims3 /usr/sbin/kamailio[12733]: [logSDID at 20306 resource="core"] ERROR: <core> [core/parser/parse_addr_spec.c:881]: parse_addr_spec(): invalid To -  unexpected end of header in state 13
Sep 21 16:41:07 vict2-ims3 /usr/sbin/kamailio[12733]: [logSDID at 20306 resource="core"] ERROR: <core> [core/parser/msg_parser.c:167]: get_hdr_field(): bad to header
Sep 21 16:41:07 vict2-ims3 /usr/sbin/kamailio[12733]: [logSDID at 20306 resource="core"] ERROR: <core> [core/parser/msg_parser.c:337]: parse_headers(): bad header field [To: sip:catt181 at vict]
Sep 21 16:41:07 vict2-ims3 /usr/sbin/kamailio[12733]: [logSDID at 20306 resource="core"] ERROR: <core> [core/parser/msg_parser.c:687]: parse_msg(): ERROR: parse_msg: message=<BYE sip:catt181 at 193.154.113.40:5065;transport=UDP;rinstance=317-catt181 SIP/2.0#015#012From: sip:catt180 at vict-ims.net;transport=UDP;tag=b7fb-dd8f-30fd-2a93fc86#015#012To: sip:catt181 at vict-ims.net;transport=UDP;tag=1ba4-ff0c-82af-415174d1;#015#012Call-ID: 1632235194213catt180#015#012CSeq: 2 BYE#015#012Contact: sip:catt180 at 193.154.113.40:5065;transport=UDP;rinstance=317-catt180#015#012Content-Length: 0#015#012Max-Forwards: 70#015#012Route: sip:mo at 172.29.21.60;r2=on;lr;ftag=b7fb-dd8f-30fd-2a93fc86;rm=8;did=281.c9a1#015#012Route: sip:mo at pcscf-1.vict-ims.net:5060;r2=on;lr;ftag=b7fb-dd8f-30fd-2a93fc86;rm=8;did=281.c9a1#015#012Route: sip:mo at vict-ims.net;lr;ftag=b7fb-dd8f-30fd-2a93fc86;did=281.b871#015#012Route: sip:mt at vict-ims.net;lr;ftag=b7fb-dd8f-30fd-2a93fc86;did=281.b871#015#012Route: sip:mt at pcscf-1.vict-ims.net;r2=on;lr;ftag=b7fb-dd8f-30fd-2a93fc86;rm=7;did=281.d9a1#015#012Route: sip:mt at 172.29.21.60:5060;r2=on;lr;ftag=b7fb-dd8f-30fd-2a93fc86;rm=7;did=281.d9a1#015#012Via: SIP/2.0/UDP 193.154.113.40:5065;branch=z9hG4bK0850615e-0#015#012#015#012>
Sep 21 16:41:07 vict2-ims3 /usr/sbin/kamailio[12733]: [logSDID at 20306 resource="core"] ERROR: <core> [core/receive.c:199]: receive_msg(): core parsing of SIP message failed (193.154.113.40:5065/1)


BR
Theo

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