[asterisk-dev] [Code Review] 3055: pbx.c: add lock around ast_exten use to prevent memory corruption

[Mark Michelson]

-----------------------------------------------------------
This is an automatically generated e-mail. To reply, visit:
https://reviewboard.asterisk.org/r/3055/#review10325
-----------------------------------------------------------



/branches/1.8/main/pbx.c
<https://reviewboard.asterisk.org/r/3055/#comment19722>

    Since these functions are local to pbx.c, declare them static. Also use "static" on the function definitions.
    
    Since the new lock is a mutex, why do you have read and write lock functions? 



/branches/1.8/main/pbx.c
<https://reviewboard.asterisk.org/r/3055/#comment19723>

    I don't understand what this is supposed to be doing. This lock doesn't actually protect anything. I suspect this may narrow the window of the race condition but it seems like whatever dangerous operation was occurring can still occur since that dangerous operation is not surrounded by the lock.


- Mark Michelson


On Dec. 6, 2013, 9:41 p.m., Scott Griepentrog wrote:
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> https://reviewboard.asterisk.org/r/3055/
> -----------------------------------------------------------
> 
> (Updated Dec. 6, 2013, 9:41 p.m.)
> 
> 
> Review request for Asterisk Developers and Matt Jordan.
> 
> 
> Bugs: AST-1179 and AST-1246
>     https://issues.asterisk.org/jira/browse/AST-1179
>     https://issues.asterisk.org/jira/browse/AST-1246
> 
> 
> Repository: Asterisk
> 
> 
> Description
> -------
> 
> During dialplan execution in pbx_extension_helper(), the contexts global read lock is used prevent changes to the dialplan.  This patch adds a lock between that point and until after the extension previously found is no longer being referenced -- after variable substitution, but before app execution.  This new lock prevents the extension's allocation from being released by module reload when it is still being used in an expression evaluation.
> 
> 
> Diffs
> -----
> 
>   /branches/1.8/main/pbx.c 403430 
> 
> Diff: https://reviewboard.asterisk.org/r/3055/diff/
> 
> 
> Testing
> -------
> 
> Testsuite test 'dialplan_stress' (https://reviewboard.asterisk.org/r/3056/) created to isolate this problem and test this fix.
> 
> 
> Thanks,
> 
> Scott Griepentrog
> 
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.digium.com/pipermail/asterisk-dev/attachments/20131206/377a8c21/attachment.html>