Re: Fwd: RFC3261 rules

Hello Sergey,

I ran into a similar issue, with both SIP requests and SIP replies.
In the end I narrow it down to a particular check that doesn't produce
an error log: content length - (128)
That particular check is comparing UDP and SIP length against the
value of the Content- Length header.
Here's the patch that will outline the issue.

diff --git a/src/modules/sanity/sanity.c b/src/modules/sanity/sanity.c
index 81f2b1b9bf..2f417d2822 100644
--- a/src/modules/sanity/sanity.c
+++ b/src/modules/sanity/sanity.c
@@ -619,7 +619,7 @@ int check_cl(sip_msg_t *msg)
                        if(sanity_reply(msg, 400, "Content-Length
mis-match") < 0) {
                                LM_WARN("failed to send 400 via sl reply\n");
                        }
-                       LM_DBG("check_cl failed\n");
+                       LM_WARN("check_cl failed: [%i - %ld] !=
[%ld]\n", msg->len, body - msg->buf, get_content_length(msg));
                        return SANITY_CHECK_FAILED;
                }
                LM_DBG("check_cl passed\n");


Hope this helps,
Ovidiu


On Sat, May 31, 2025 at 3:38 AM Sergey Safarov via sr-users
<[email protected]> wrote:
>
> Could you look at the attached PCAP with OPTIONS message. When OPTIONS message is received, then Kamailio generates error logs like
>
> dropping insane message from 10.140.6.38:60083
>
> After checking the PCAP, I see extra %x00 characters after the OPTIONS message in the same UDP frame.
> Example
>
>
> I have checked RFC3261 and do not see a definition of "x00" chars.
> Also in the same RFC, present a reference to the RFC2234 where is described "space chars", "white space". According to RFC2223, char %x00 cannot be treated as "space" and should be treated as control (CTL) char.
> Also, RFC3261 does not use "CTL" chars.
>
> Using these two RFC, I can conclude, OPTIONS in the attached PCAP breaks RFC requirements, and we can request partner fix this issue on their equipment.
>
> Is anything else in the RFC can be used to justify that the given examples of OPTIONS messages violate RFCs?
>
> Sergey
>
>
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