On Thu, Feb 24, 2022 at 10:56:09AM +0100, Geert Uytterhoeven wrote:
Hi David, Kees,
On Thu, Feb 24, 2022 at 10:54 AM David Laight <David.Laight@xxxxxxxxxx> wrote:
From: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Sent: 24 February 2022 09:17
On Thu, Feb 24, 2022 at 10:12 AM David Laight <David.Laight@xxxxxxxxxx> 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?
Kernel, the kernel doesn't care if the user stack gets trashed.
Right, this is strictly a kernel-side check in mm/usercopy.c:
https://lore.kernel.org/linux-hardening/20220225173345.3358109-1-keescook@xxxxxxxxxxxx/
OK.
Reviewed-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Kees: Do you want me to queue this in the m68k for-v5.18 branch, or do
you want to take it yourself, together with the HARDENED_USERCOPY work?
In case of the latter:
Acked-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Please let me know. Thanks!
Yeah, I'll take it via my tree, just so it's all together.
Thanks!
-Kees
--
Kees Cook
