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Re: Bug in bash <= 4.3 [security feature bypassed]

On 05/06/14 12:02, Daryl Tester wrote:
On 03/06/14 23:46, Hector Marco wrote:

Recently we discovered a bug in bash. After some time after reporting
it to bash developers, it has not been fixed.


Any comments about this issue are welcomed.

Details at:

I'm only going by the patch presented above, so ...

1.  The program should be calling setgid() before setuid() (which is
another common class of security mistake).
2.  Why is exit() returning values greater than 255?  It's not capable
of doing that under (most) Unix environments.

a) I tried to patch by doing minimal changes to bash source code. Originally, the bash call first setuid() and later setgid(). And as you point this is not the best option. So, this code has actually 2 mistakes. I changed the patch code order calls, thanks, but anyway the patch achieve their goal, "avoid the bash
    to be a valid target shell in an attack".

b) I can imagine why you spent time writing about the patch and not about the
    important point here which is the bug.