Re: [PATCH v7 5/6] x86/signal: Detect and prevent an alternate signal stack overflow
From: Borislav Petkov <bp@alien8.de>
Date: 2021-04-14 10:12:55
Also in:
linux-arch, lkml
On Mon, Apr 12, 2021 at 10:30:23PM +0000, Bae, Chang Seok wrote:
On Mar 26, 2021, at 03:30, Borislav Petkov [off-list ref] wrote:quoted
On Thu, Mar 25, 2021 at 09:56:53PM -0700, Andy Lutomirski wrote:quoted
We really ought to have a SIGSIGFAIL signal that's sent, double-fault style, when we fail to send a signal.Yeap, we should be able to tell userspace that we couldn't send a signal, hohumm.Hi Boris, Let me clarify some details as preparing to include this in a revision. So, IIUC, a number needs to be assigned for this new SIGFAIL. At a glance, not sure which one to pick there in signal.h -- 1-31 fully occupied and the rest for 33 different real-time signals. Also, perhaps, force_sig(SIGFAIL) here, instead of return -1 -- to die with SIGSEGV.
I think this needs to be decided together with userspace people so that they can act accordingly and whether it even makes sense to them. Florian, any suggestions? Subthread starts here: https://lkml.kernel.org/r/CALCETrXQZuvJQrHDMst6PPgtJxaS_sPk2JhwMiMDNPunq45YFg@mail.gmail.com Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette