On Thu, Mar 12, 2015 at 01:57:51PM -0700, Andy Lutomirski wrote: > From: Andy Lutomirski <[email protected]> > > The comment in the signal code says that apps can save/restore other > segments on their own. It's true that apps can *save* SS on their > own, but there's no way for apps to restore it: SYSCALL effectively > resets SS to __USER_DS, so any value that user code tries to load > into SS gets lost on entry to sigreturn. > > This recycles two padding bytes in the segment selector area for SS. > > While we're at it, we need a second change to make this useful. If > the signal we're delivering is caused by a bad SS value, saving that > value isn't enough. We need to remove that bad value from the regs > before we try to deliver the signal. Oddly, x32 already got this > right. > > I suspect that 64-bit programs that try to run 16-bit code and use > signals will have a lot of trouble without this. > > Signed-off-by: Andy Lutomirski <[email protected]>
Acked-by: Borislav Petkov <[email protected]> -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
