* H. Peter Anvin <hpa@xxxxxxxxxxxxxxx> wrote: > On 04/11/2014 11:41 AM, Linus Torvalds wrote: > > > > Ok, so you actually do this on x86-64, and it currently works? For > > some reason I thought that 16-bit windows apps already didn't work. > > > > Some will work, because not all 16-bit software care about the upper > half of ESP getting randomly corrupted. > > That is the "functionality bit" of the problem. The other bit, of > course, is that that random corruption is the address of the kernel stack. > > > Because if we have working users of this, then I don't think we can do > > the "we don't support 16-bit segments", or at least we need to make it > > runtime configurable. > > I'll let you pick what the policy should be here. I personally > think that we have to be able to draw a line somewhere sometimes > (Microsoft themselves haven't supported running 16-bit binaries for > several Windows generations now), but it is your policy, not mine. I think the mmap_min_addr model works pretty well: - it defaults to secure - allow a security policy to grant an exception to a known package, built by the distro - end user can also grant an exception This essentially punts any 'makes the system less secure' exceptions to the distro and the end user. Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html