[Home]

Summary:ASTERISK-24449: Reinvite for T.38 UDPTL fails if SRTP is enabled
Reporter:Andreas Steinmetz (anstein)Labels:
Date Opened:2014-10-24 18:17:56Date Closed:2014-12-16 10:40:02.000-0600
Priority:MinorRegression?No
Status:Closed/CompleteComponents:Channels/chan_sip/T.38
Versions:11.13.0 Frequency of
Occurrence
Constant
Related
Issues:
Environment:Attachments:( 0) srtp-udptl.patch
( 1) udptl-ignore-srtp-v2.patch
Description:Asterisk does erroneously respect the SRTP setting for the SIP account when handling a reinvite for T.38 UDPTL.
Furthermore there are ATAs like the Cisco SPA112 that, in a T.38 UDPTL reinvite response, send "a=crypto" lines which seems to be plain wrong.

Quote from RFC4612:
"Further, there are no procedures in place for encrypting and protecting the integrity ofthe UDPTL stream."

Thus Asterisk needs to ignore anything related to SRTP when handling any T.38 UDPTL reinvite.
Comments:By: Andreas Steinmetz (anstein) 2014-10-24 18:24:18.199-0500

Patch to ignore SRTP for T.38 UDPTL reinvite. Seems to work for me though I don't know if the patch causes other problems.

By: Andreas Steinmetz (anstein) 2014-10-28 10:34:25.925-0500

Version 2 of the patch, tighter check to prevent erroneous triggering.

By: Rusty Newton (rnewton) 2014-11-03 16:46:17.506-0600

Thanks [~anstein] ! Please see the [Patch Contribution Process|https://wiki.asterisk.org/wiki/display/AST/Patch+Contribution+Process] to move forward with the patch. Once you get the patch on [Reviewboard|https://wiki.asterisk.org/wiki/display/AST/Review+Board+Usage] you can edit this issue and add the URL to the Reviewboard URL field for reference.