Re: -fno-stack-protector and musl

[Rich Felker <dalias@aerifal.cx>]

On Mon, Oct 21, 2013 at 11:20:06PM +0800, Christopher Meng wrote:
> Hi all,
> 
> I'm going to package this c lib into Fedora for skalibs. However
> Fedora forces us to package every pkg with optflags inserted:

I can assure you glibc is not compiled with stack protector either, so
there are exceptions to this policy. :) You should just cite such an
exception.

It's my long-term goal to support compiling musl itself with stack
protector, but this is dependent on groundwork in two areas:

1. There needs to be a way to force stack protector off in at least a
   few files which are needed for early initialization, before the
   canary is available. This needs build system support and call tree
   analysis of what files need such special handling.

2. Since the canary is stored at a fixed offset from the thread
   pointer, the thread pointer must always be initialized when ssp is
   used. This is handled correctly now (modulo one gcc bug) for apps
   and libs that use ssp, but not for libc-internal use. In the 1.1
   series I plan to make the thread pointer always-initialized.

I expect the resolution of this issue somewhere in the early to mid
1.1 series. For what it's worth, we're no worse than glibc in this
regard right now, and hope to be better in the future.

Rich