Re: Needed for the release

[jhd]

> Masatake YAMATO <address@hidden> writes:
>
>
> > Sorry to be late.
> >
> >
> > > exec_shield is one such feature, and newer kernels use something
> > > like, uh, /proc/sys/vm/randomize_... (I don't remember the
> > > particular name right now and don't have a Fedora active).  The
> > > latter loaded executables' memory segments into randomized
> > > locations to make buffer overflow attacks less predictable.
> > >
> > > exec_shield could be gotten around with using
> > > setarch i386 make
> > > and configure does that already IIRC.  But the address space
> > > randomization was prohibiting the dumping even with the setarch
> > > command.
> >
> > Could you tell me the kernel version or the OS version?
> >
> > I'm using Fedora core 1 and Fedora core 3.
> > I cannot reproduce the problem on the platforms.
>
> It was introduced some time after Fedora core 3 in their development
> sources.  I switched to Ubuntu a short time after that.  It is
> possible that the feature did not make it switched on by default into
> the final FC4 release, but I can't tell since I stopped updating it
> after that.


If exec-shield is disabled or if the workaround in emacs.c works you  
won't see any problems.  But the workaround is to set personality to  
PER_LINUX32 and that may have other problems.  For example, does it  
work on a 64-bit system?  What about non-x86 architectures?  Does  
setting PER_LINUX32 have other side effects?

Ideally unexec should handle the case where heap and bss is not next  
to each other, and then this workaround can be removed.

    Jan D.