[asterisk-bugs] [Asterisk 0014623]: [patch] Race condition between bridge and channel masquerading

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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http://bugs.digium.com/view.php?id=14623 
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Reported By:                guillecabeza
Assigned To:                russell
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Project:                    Asterisk
Issue ID:                   14623
Category:                   Core/Channels
Reproducibility:            sometimes
Severity:                   crash
Priority:                   normal
Status:                     assigned
Asterisk Version:           SVN 
Regression:                 No 
SVN Branch (only for SVN checkouts, not tarball releases):  trunk 
SVN Revision (number only!): 180032 
Request Review:              
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Date Submitted:             2009-03-08 16:07 CDT
Last Modified:              2009-03-09 18:33 CDT
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Summary:                    [patch] Race condition between bridge and channel
masquerading
Description: 
The bridge checks for zombieness

/* Stop if we're a zombie or need a soft hangup */
		if (ast_test_flag(c0, AST_FLAG_ZOMBIE) || ast_check_hangup_locked(c0)
||
		    ast_test_flag(c1, AST_FLAG_ZOMBIE) || ast_check_hangup_locked(c1))
{

To see if some of the channels is going through a masquerading, but non
atomically, access to channel member variables happens a few lines later

if (!ast_strlen_zero(pbx_builtin_getvar_helper(c0, "BRIDGEPEER")))
     pbx_builtin_setvar_helper(c0, "BRIDGEPEER", c1->name);

Without locking on those acceses. That causes random crashes when the
memory is touched or free'd later.

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---------------------------------------------------------------------- 
 (0101434) guillecabeza (reporter) - 2009-03-09 18:33
 http://bugs.digium.com/view.php?id=14623#c101434 
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I think potentially your patch is better (I really don't like usleep's
dangling around that much). But for consistency I think everywhere should
use the same strategy when faced with the same problem, that would mean
changing ast_channel_masquerade also...

my 2 cents. 

Issue History 
Date Modified    Username       Field                    Change               
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2009-03-09 18:33 guillecabeza   Note Added: 0101434                          
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