lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Thu, 24 Feb 2022 10:16:45 +0100
From:   Geert Uytterhoeven <>
To:     David Laight <>
Cc:     Kees Cook <>,
        linux-m68k <>,
        Linux Kernel Mailing List <>,
        "" <>
Subject: Re: [PATCH] m68k: Implement "current_stack_pointer"

On Thu, Feb 24, 2022 at 10:12 AM David Laight <> wrote:
> From: Geert Uytterhoeven
> > Sent: 24 February 2022 08:59
> ...
> > > +register unsigned long current_stack_pointer __asm__("sp");
> >
> > I don't know what HARDENED_USERCOPY does, so I don't know if you need
> > "usp" (see rdusp()) or "sp"?
> HARDENED_USERCOPY significantly slows down some systems calls
> (especially things like sendmsg()) by trying to run-time verify
> that the kernel buffer doesn't overrun a stack frame or kmalloc()ed

Kernel stack frame of user stack frame?

> buffer.
> I've got measurable improvements by either using __copy_to/from_user()
> (which skips the tests) or user_access_begin() and __get_user().
> At the moment the code for reading a compat iovec[] is actually
> faster than that for a native one!



Geert Uytterhoeven -- There's lots of Linux beyond ia32 --

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Powered by blists - more mailing lists