On Tue, Feb 21, 2012 at 11:03 AM, H. Peter Anvin <hpa@xxxxxxxxx> wrote: > On 02/21/2012 10:54 AM, Andrew Lutomirski wrote: >> >> uclibc hardcodes a call to the vsyscall gettimeofday implementation in >> its locking primitives, which probably gives terrible performance, but >> that's a separate issue. I think do_emulate_vsyscall should send a >> segfault if called by an x32 task -- there's some security benefit to >> doing so, and there's unlikely to be any downside. >> > > The vsyscall page shouldn't be mapped for x32 tasks... How is that possible? It lives in the fixmap and is presumably visible from any 64-bit code. Admittedly, x32 tasks are probably somewhat difficult to trick into calling addresses with high bits set, but it's not necessarily impossible. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
