Summary:ASTERISK-23989: [patch]SDP offer/answer fails if crypto keys added to non-crypto offer
Reporter:Olle Johansson (oej)Labels:
Date Opened:2014-07-03 01:36:32Date Closed:2016-10-26 08:59:47
Versions: Frequency of
duplicatesASTERISK-18201 Asterisk should fall back to AVP when SRTP module is not loaded and both SAVP and AVP have been offered
duplicatesASTERISK-22675 Asterisk refuses correct RTP/AVP with optional encryption
is related toASTERISK-20234 SRTP not working with some devices (Eg snom320) - Message "We are requesting SRTP for audio, but they responded without it!"
Environment:Planet earthAttachments:( 0) sdes-rtp-avp.diff
Description:1) We got a new SNOM phone configured so it offered RTP/AVP but for some reason added a=crypto SDES keys.
2) Microsoft Lync offers RTP/AVP and optional RTP/SAVP in the same SDP, also adding keys if RTP/SAVP is accepted

Asterisk fails offer answer with the message:
"We are requesting SRTP for audio, but they responded without it!"
and sends 488. This error message is wrong and failing is wrong.

We should ignore non-relevant attributes. If RTP/AVP is the offer, just don't check for the crypto keys and activate p->srtp.
Comments:By: Olle Johansson (oej) 2014-07-03 01:39:04.318-0500

I guess this patch will work. Will test during today's work.

By: Rusty Newton (rnewton) 2014-07-08 18:47:36.936-0500

Feel free to throw it on reviewboard for some others to test/review.

By: Rusty Newton (rnewton) 2014-07-08 18:53:49.336-0500

[~oej] I found ASTERISK-22675 and ASTERISK-20234 which may be the same or related issues. Can you verify?

By: Walter Doekes (wdoekes) 2016-09-06 03:12:14.203-0500

Git reviews:

https://gerrit.asterisk.org/#/c/3234/ <-- by Alexander Traud, does the inverse and accepts the SRTP
https://gerrit.asterisk.org/#/c/3828/ <-- by me, a more complete version of sdes-rtp-avp.diff