On Sun, Dec 23, 2012 at 02:49:08PM -0500, Tom Lane wrote:
> Noah Misch <n...@leadboat.com> writes:
> > On Sat, Dec 22, 2012 at 02:20:56PM -0500, Tom Lane wrote:
> >> #ifdef USE_SSL
> >> if (EnableSSL)
> >> {
> >>    struct timeval tv;
> >> 
> >>    gettimeofday(&tv, NULL);
> >>    RAND_add(&tv, sizeof(tv), 0);
> >> }
> >> #endif
> 
> > Take the caution one step further and make it independent of EnableSSL.  In 
> > a
> > stock installation, a !EnableSSL postmaster will never seed its PRNG, and
> > there's no vulnerability.  Add a shared_preload_libraries module that uses 
> > the
> > OpenSSL PRNG in its _PG_init(), and suddenly you're vulnerable again.
> 
> Meh.  In a postmaster that wasn't built with SSL support at all, such
> a module is still dangerous (and I'm not convinced anybody would build
> such a module anyway).  I think we should confine our ambitions to
> preventing security issues caused by our own code.

You're adding lines of code to prematurely micro-optimize the backend fork
cycle.  If code introduced into the postmaster, by us or others, ever violates
the assumption behind that micro-optimization, certain users get a precipitous
loss of security with no clear alarm bells.  I don't like that trade.

nm


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