Bug or feature ...

Kees Cook kees at ubuntu.com
Wed Apr 6 22:14:38 UTC 2011


On Wed, Apr 06, 2011 at 02:53:46PM -0700, Kees Cook wrote:
> On Wed, Apr 06, 2011 at 05:35:07PM -0400, Scott Kitterman wrote:
> > He offers this as a test case:
> 
> I can confirm the behavior difference between maverick and natty by doing
> this:
> 
> while ./testcase.pl ; do echo -n . ; done
> 
> On maverick, this runs forever. Natty immediately fails:
> 
> Parent 792
> 
> Child 793
> .bind: Address already in use at ./testcase.pl line 9.
> 
> 
> I hope this is a Net::Server delta and not a kernel delta.

This looks like a kernel bug to me. I can reproduce it with C as well.

$ ./testcase
parent: 3781
before:
tcp        0      0 0.0.0.0:12345           0.0.0.0:*               LISTEN     
after:
child: 3786

$ ./testcase
bind: Address already in use

$ kill 3786

$ ./testcase
parent: 3810
before:
tcp        0      0 0.0.0.0:12345           0.0.0.0:*               LISTEN     
after:
child: 3817

:(

-- 
Kees Cook
Ubuntu Security Team
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