Hello Theodor,

I have not checked the specific section of 3261 right now. But generally, pull request are accepted if it fixes some limitation with regards to the SIP standards or provide an extension in this regard. And your description sounds like this. There might be some technical changes necessary, if discovered or discussed during the usual review process.

Cheers,

Henning

Henning Westerholt – https://skalatan.de/blog/

Kamailio services – https://gilawa.com

From: sr-dev <sr-dev-bounces@lists.kamailio.org> On Behalf Of Scherney Theodor
Sent: Tuesday, September 28, 2021 2:55 PM
To: 'sr-dev@lists.kamailio.org' <sr-dev@lists.kamailio.org>
Cc: Onic Roman <Roman.Onic@kontron.com>; Valentin Christoph <Christoph.Valentin@kontron.com>
Subject: Re: [sr-dev] Syntax error

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.

Theo

Von: sr-dev <sr-dev-bounces@lists.kamailio.org> Im Auftrag von Scherney Theodor
Gesendet: Mittwoch, 22. September 2021 09:24
An: 'sr-dev@lists.kamailio.org' <sr-dev@lists.kamailio.org>
Cc: Onic Roman <Roman.Onic@kontron.com>; Valentin Christoph <Christoph.Valentin@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@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@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@20306 resource="core"] ERROR: <core> [core/parser/parse_from.c:75]: parse_from_header(): bad From header [sip:catt180@vict-ims.net;transport=UDP;tag=b3af-8e5a-1e36-79340f18;]

Sep 21 16:44:51 vict2-ims3 /usr/sbin/kamailio[12723]: [logSDID@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@20306 resource="xlog"] INFO: <script>: route BYE (<null> (193.154.113.40:5065) to sip:catt181@vict-ims.net, 1632235417904catt180, )

Sep 21 16:44:51 vict2-ims3 /usr/sbin/kamailio[12723]: [logSDID@20306 resource="xlog"] INFO: <script>: BYE (BYE sip:catt181@193.154.113.40:5065;transport=UDP;rinstance=317-catt181 SIP/2.0#015#012From: sip:catt180@vict-ims.net;transport=UDP;tag=b3af-8e5a-1e36-79340f18;#015#012To: sip:catt181@vict-ims.net;transport=UDP;tag=9d7b-d1c6-c06b-7a1dbec7#015#012Call-ID: 1632235417904catt180#015#012CSeq: 2 BYE#015#012Contact: sip:catt180@193.154.113.40:5065;transport=UDP;rinstance=317-catt180#015#012Content-Length: 0#015#012Max-Forwards: 70#015#012Route: sip:mo@172.29.21.60;r2=on;lr;ftag=b3af-8e5a-1e36-79340f18;rm=8;did=8ed.6e12#015#012Route: sip:mo@pcscf-1.vict-ims.net:5060;r2=on;lr;ftag=b3af-8e5a-1e36-79340f18;rm=8;did=8ed.6e12#015#012Route: sip:mo@vict-ims.net;lr;ftag=b3af-8e5a-1e36-79340f18;did=8ed.e7b1#015#012Route: sip:mt@vict-ims.net;lr;ftag=b3af-8e5a-1e36-79340f18;did=8ed.e7b1#015#012Route: sip:mt@pcscf-1.vict-ims.net;r2=on;lr;ftag=b3af-8e5a-1e36-79340f18;rm=7;did=8ed.7e12#015#012Route: sip:mt@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@20306 resource="sanity"] WARNING: sanity [sanity.c:776]: check_parse_uris(): failed to parse From header [sip:catt180@vict-ims.net;transport=UDP;tag=b3af-8e5a-1e36-79340f18;]

Sep 21 16:44:51 vict2-ims3 /usr/sbin/kamailio[12723]: [logSDID@20306 resource="xlog"] INFO: <script>: t_relay_send_reply_sl - BYE (SIP/2.0 400 Bad From header#015#012From: sip:catt180@vict-ims.net;transport=UDP;tag=b3af-8e5a-1e36-79340f18;#015#012To: sip:catt181@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@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@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@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@20306 resource="core"] ERROR: <core> [core/parser/msg_parser.c:337]: parse_headers(): bad header field [To: sip:catt181@vict]

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

Theo