[Fedora-packaging] Override with -D_FORTIFY_SOURCE=0 as workaround allowed?

[Daniel P. Berrange]

On Tue, Jan 10, 2012 at 11:25:39AM +0100, Robert Scheck wrote:
> Hello Tom,
> 
> On Mon, 09 Jan 2012, Tom Lane wrote:
> > I think the reason this hasn't been complained of too much is that
> > it's generally better to use poll(2) instead of select(2) if your
> > program can have a lot of file descriptors open.  Have the Zarafa
> > developers considered offering a poll()-based option?
> 
> I have taken that topic already to Zarafa, more than void was not yet
> returned, however there is an internal developer meeting this week, I
> think.
> 
> Even if they decide to rewrite the code, it's not done immediately and
> non-paid code rewrites maybe also take some time, it's similar like at
> RHEL vs. subscription, if I'm allowed to compare.
> 
> Would -D_FORTIFY_SOURCE=0 be acceptable until the code is rewritten?

As Tom pointed out, if you override FD_SETSIZE with glibc, this has
no effect on the size of the 'fd_set' struct. So any attempt to
actually store a larger number of FDs will be writing outside
the bounds of the struct. ie it will be corrupting heap/stack
memory. This is the kind of flaw that leads to crashes at best,
or security exploits at worst.

Thus, IMHO, it is not acceptable to set -D_FORTIFY_SOURCE=0.
You'd be building known broken, potentially insecure binaries.

Regards,
Daniel
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