[asterisk-bugs] [Asterisk 0018674]: [patch] Unable to choose which SRTP suite to offer

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=18674 
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Reported By:                bbeers
Assigned To:                
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Project:                    Asterisk
Issue ID:                   18674
Category:                   Channels/chan_sip/SRTP
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     feedback
Asterisk Version:           SVN 
JIRA:                        
Regression:                 No 
Reviewboard Link:            
SVN Branch (only for SVN checkouts, not tarball releases):  trunk 
SVN Revision (number only!): 303637 
Request Review:              
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Date Submitted:             2011-01-25 09:56 CST
Last Modified:              2011-02-01 08:42 CST
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Summary:                    [patch] Unable to choose which SRTP suite to offer
Description: 
Setting encryption=yes in sip.conf will cause asterisk to
 generate a line in SIP INVITE SDP:

 a=crypto: AES_CM_128_HMAC_SHA1_80 ...

There is no way to specify that asterisk should offer
 AES_CM_128_HMAC_SHA1_32 instead of
 AES_CM_128_HMAC_SHA1_80.

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 (0131346) bbeers (reporter) - 2011-02-01 08:42
 https://issues.asterisk.org/view.php?id=18674#c131346 
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lmadsen:  wimpy asked a similar question on 25 Jan.  I'm anticipating a
future where we have an audio+video call that may requires different
suites.  Ther could be some other new parameters becoming available,
perhaps encryption_audio, encryption_video, encryption_text, that would
override the "default" encryption_suite if necessary.  Leaving
encyption=[yes|no] also allows for quickly turning off all encryption
without changing all the other params (probably only useful for
testing/debugging).  Also, I had intended that the current patch does allow
for backward compatibility.  Is that not the case?

giles:  I'll look at that warning (I think it is due to return value of a
libsrtp function call, srtp_unprotect_rtcp or srtp_unprotect) and see if I
can tell what is happening.  I didn't notice it during my testing, but I
will look more carefully. 

Issue History 
Date Modified    Username       Field                    Change               
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2011-02-01 08:42 bbeers         Note Added: 0131346                          
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