Summary:	ASTERISK-22832: Support AES-GCM mode in SRTP
Reporter:	Kristian Kielhofner (krisk)	Labels:
Date Opened:	2013-11-08 12:10:23.000-0600	Date Closed:	2016-12-27 05:53:08.000-0600
Priority:	Minor	Regression?	No
Status:	Closed/Complete	Components:	Channels/chan_sip/SRTP
Versions:	SVN	Frequency of Occurrence
Related Issues:	is contained by ASTERISK-26190 [patch] SRTP: Enable AES-256 and AES-GCM.
Environment:	Linux x86_64	Attachments:	( 0) asterisk_gcm_draft10.patch ( 1) asterisk_gcm.patch ( 2) asterisk-1.8-srtp-crypto_kernel-include.patch
Description:	There is a version of libsrtp that supports AES-NI and AES-GCM mode: https://github.com/cisco/libsrtp/pull/34 More on AES-GCM mode: http://tools.ietf.org/html/draft-ietf-avtcore-srtp-aes-gcm-10 https://crypto.stanford.edu/RealWorldCrypto/slides/gueron.pdf AES-GCM mode improves the performance of SRTP on systems with and without support for the AES-NI instruction set. Performance test results pending.
Comments:	By: Kristian Kielhofner (krisk) 2013-11-08 12:11:49.386-0600 This patch supports AEAD_AES_GCM_128_8 with Asterisk trunk. Tested with pjsip 2.1 with AES-GCM patches applied. pjsip source here: https://github.com/krisk84/PJSIP By: Matt Jordan (mjordan) 2013-11-11 10:51:29.241-0600 Well, that's a fairly straight forward patch. I might recommend re-ordering the {{ast_srtp_suite}} enumeration to line up with the {{#defined}} constants, but that's just a nit-pick. Thanks for the contribution! By: Rusty Newton (rnewton) 2014-03-12 12:25:40.142-0500 Kristian, you'll want to go ahead and get your patch on reviewboard to get more eyeballs on it. Here is the [Code Review process|https://wiki.asterisk.org/wiki/display/AST/Code+Review] on the wiki which describe the general process and how to use reviewboard. By: Kristian Kielhofner (krisk) 2014-03-13 12:53:57.221-0500 Update crypto suite names to latest draft (10). By: Kristian Kielhofner (krisk) 2014-03-13 12:55:04.229-0500 I also created a ReviewBoard entry with the latest patch: https://reviewboard.asterisk.org/r/3350/ By: abelbeck (abelbeck) 2014-10-14 09:52:06.380-0500 Adds srtp/crypto_kernel.h include to res/res_srtp.c for libsrtp 1.5.0 By: abelbeck (abelbeck) 2014-10-14 10:06:30.721-0500 Attached is trivial patch to res/res_srtp.c to also include srtp/crypto_kernel.h This is related to Kristian's issue here as the libsrtp version 1.5.0 ( https://github.com/cisco/libsrtp ) has rearranged some of the header files, and crypto_kernel.h is not longer included in srtp.h.  Without the patch you see: {noformat}  [CC] res_srtp.c -> res_srtp.o res_srtp.c: In function 'ast_srtp_get_random': res_srtp.c:307: warning: implicit declaration of function 'crypto_get_random'  [LD] res_srtp.o -> res_srtp.so {noformat} The included patch should be backward compatible, and should apply to all versions of Asterisk. Using libsrtp version 1.5.0  offers OpenSSL support and it's AES optimizations. By: Alexander Traud (traud) 2016-07-13 07:21:28.083-0500 [~abelbeck], thank you for reporting that issue with {{crypto_get_random}}. It got its own issue report. Therefore, please, continue with ASTERISK-24436. [~agbsres], the attached patch targeted the master branch at that time, which created Asterisk 13. If you are looking for a backport of AES-GCM for Asterisk 11, please, do give a rationale why you cannot update to Asterisk 13 and why you want AES-GCM. That raises motivation and might help to find an Asterisk team member or a community member, to create such a patch. @all In December 2015, that draft matured to RFC 7714. However in June 2014 with draft revision 13, the crypto suite {{AEAD_AES_128_GCM_8}} got dropped. Furthermore even back than, there was a bug in libSRTP because the key length (actually the master salt) was too long. This patch here relied on the fact that the key length was the same as for {{AES_CM_128_HMAC_SHA1_80}}. This is not the case anymore. Therefore, please, let us continue with ASTERISK-26190. By: Alexander Traud (traud) 2016-12-27 05:53:09.006-0600 Kristian, I am closing this report because sRTP supports AES-GCM since Asterisk 14. Your patch was a helpful starting point. If you want to see this variant of AES-GCM (discussed here in this report) to be implemented as well, please, re-open this issue report. In that case, please, specify which products still require/rely on this AES-GCM draft.