[asterisk-dev] [Code Review] Security Event Framework Proposal

Russell Bryant russell at digium.com
Tue Jun 16 21:51:54 CDT 2009



> On 2009-06-16 12:36:47, Mark Michelson wrote:
> > /trunk/main/manager.c, lines 1757-1758
> > <http://reviewboard.digium.com/r/273/diff/5/?file=5640#file5640line1757>
> >
> >     I'll knock out two birds with one stone.
> >     
> >     1) There's no reason to initialize sin_local in these functions.
> >     
> >     2) What's the benefit of using ast_str objects here? I'd think using a char * and ast_strdupa would require less overhead and provide the same benefit. If you're trying to limit the output to a certain length, then a static buffer and ast_copy_string would work, too.
> 
>  wrote:
>     Actually, ast_strdupa() / ast_copy_string() wouldn't work because the session ID is not coming from a string.
>     
>     However, your comment still applies as I could use snprintf() on a constant size buffer instead of ast_str_set().
>     
>     Regarding ast_str versus an array, it's a toss up to me.  I suppose my thinking was that it made sense to always use ast_str unless there was a good reason not to for the sake of consistency.  I figured ast_str was the preferred way to do almost all string operations now, but I suppose it's not something we have discussed specifically.
> 
>  wrote:
>     I wasn't aware of this preferred shift to using ast_str for string operations. Why do you consider it "consistent" to use ast_strs here when all you are actually using of the ast_str is the buffer portion of it and you limit its length? I thought that ast_str was useful because it could expand if necessary and because it has convenient set and append operations.

It's really not useful here.  I think I was trying to come up with a justification for not having to change it.  :-)

I'll change it.


- Russell


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On 2009-06-16 17:24:24, Russell Bryant wrote:
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> http://reviewboard.digium.com/r/273/
> -----------------------------------------------------------
> 
> (Updated 2009-06-16 17:24:24)
> 
> 
> Review request for Asterisk Developers.
> 
> 
> Summary
> -------
> 
> This is a security framework for Asterisk.  This is essentially the documentation and implementation of the ideas discussed at a couple of the recent developer meetings.  The documentation resides in doc/tex/security-events.tex.
> 
> The code is an implementation of this framework.  The changes can be broken down in this way:
> 
>    1) Security event API
>       - main/security_events.c
>       - include/asterisk/security_events.h
>       - include/asterisk/security_events_defs.h
> 
>    2) Changes to the ast_event API to support security events
>       - include/asterisk/event_defs.h
>       - main/event.c
> 
>    3) A consumer of security events to produce a security log file
>       - res/res_security_log.c
> 
>    4) A completed producer of security events
>       - main/manager.c
> 
>    5) The beginning of having chan_sip produce some security events
>       ******************
>       *** NOTE: I do not propose that this part get merged now.  I think we
>       *** should handle the chan_sip mods as another patch in a second phase.
>       ******************
>       - channels/chan_sip.c
> 
>    6) A test module that generates every type of security event
>       - tests/test_security_events.c
> 
>    7) A simple test script that gets the manager interface to generate
>       one of every type of security event it emits.
>       **************
>       *** NOTE: Is this worth merging?
>       **************
>       - tests/test_ami_security_events.sh
> 
> 
> The security event API is essentially a helper API on top of the ast_event API.  I knew going in to this that there was a lot of data that we wanted in each event.  Forcing producers to use really big ast_event_new() calls, and forcing them to do the payload formatting seemed very error prone and more difficult then necessary.  So, I came up with this API that uses structure definitions of each event type and code in the core that converts these structures into events.  The code also detects if a producer of events forgot to fill in a field that was required.  Also, I put structure version fields in each of these helper structures for the sake of ABI protection.
> 
> As a final note, one notable feature that is not yet present is the ability to fire off custom security events from the dialplan.  I haven't come up with an interface for it that I am happy with just yet.  I think we can handle this as another patch later.
> 
> 
> Diffs
> -----
> 
>   /trunk/doc/tex/asterisk.tex 201216 
>   /trunk/doc/tex/security-events.tex PRE-CREATION 
>   /trunk/include/asterisk/event_defs.h 201216 
>   /trunk/include/asterisk/security_events.h PRE-CREATION 
>   /trunk/include/asterisk/security_events_defs.h PRE-CREATION 
>   /trunk/main/event.c 201216 
>   /trunk/main/manager.c 201216 
>   /trunk/main/security_events.c PRE-CREATION 
>   /trunk/res/res_security_log.c PRE-CREATION 
>   /trunk/channels/chan_sip.c 201216 
>   /trunk/tests/test_ami_security_events.sh PRE-CREATION 
>   /trunk/tests/test_security_events.c PRE-CREATION 
> 
> Diff: http://reviewboard.digium.com/r/273/diff
> 
> 
> Testing
> -------
> 
> There are two major components of the testing that has been done:
> 
>    1) There is a test module that generates every type of security event.  You can run the test CLI command and verify that the events come out in the custom security log channel, demonstrating the documented security log format:
> 
> Here is some example output:
> 
> *CLI> securityevents test generation
> 
> ...
> 
> SECURITY[17921]: res_security_log.c:125 security_event_cb: SecurityEvent="FailedACL",Service="TEST",EventVersion="1",AccountID="Username",SessionID="Session123",LocalAddress="IPV4/UDP/192.168.1.1/12121",RemoteAddress="IPV4/UDP/192.168.1.2/12345",Module="test_security_events",ACLName="TEST_ACL",SessionTV="1244131376-695232"
> 
> ...
> 
>    2) There is also a script that gets the Asterisk Manager Interface to produce at least one of every type of security event that it produces.  This has been executed and the output has been verified to be what is expected.
> 
> 
> Thanks,
> 
> Russell
> 
>




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