Hi Bob.
On Tue, Feb 18, 2014 at 02:11:18PM -0500, Bob Picco wrote:
> From: bob picco <bpicco@xxxxxxxxxx>
>
> This is just the first part of restricting /dev/mem access on sparc.
> This patch does nothing to change the current behaviour. The patch is
> in preparation for a subsequent patch.
>
> Signed-off-by: Bob Picco <bob.picco@xxxxxxxxxx>
> ---
> arch/sparc/Kconfig.debug | 8 ++++++++
> arch/sparc/include/asm/page_64.h | 1 +
> arch/sparc/mm/init_64.c | 11 +++++++++++
> 3 files changed, 20 insertions(+), 0 deletions(-)
>
> diff --git a/arch/sparc/Kconfig.debug b/arch/sparc/Kconfig.debug
> index 6db35fb..92f2388 100644
> --- a/arch/sparc/Kconfig.debug
> +++ b/arch/sparc/Kconfig.debug
> @@ -6,6 +6,14 @@ config TRACE_IRQFLAGS_SUPPORT
>
> source "lib/Kconfig.debug"
>
> +config STRICT_DEVMEM
> + bool "Filter access to /dev/mem"
> + ---help---
> + If this option is disabled, you allow userspace (root) access to all
> + of memory, including kernel and userspace memory. Accidental
> + access to this is obviously disastrous, but specific access can
> + be used by people debugging the kernel.
> +
Grumble - this really belongs in an arch neutral file,
and then archs that support it should select HAVE_STRICT_DEVMEM
> diff --git a/arch/sparc/include/asm/page_64.h b/arch/sparc/include/asm/page_64.h
> index aac53fc..e54ee50 100644
> --- a/arch/sparc/include/asm/page_64.h
> +++ b/arch/sparc/include/asm/page_64.h
> @@ -36,6 +36,7 @@ extern void hugetlb_setup(struct pt_regs *regs);
>
> #define WANT_PAGE_VIRTUAL
>
> +extern int devmem_is_allowed(unsigned long pagenr);
> extern void _clear_page(void *page);
> #define clear_page(X) _clear_page((void *)(X))
> struct page;
Grumble - and this prototype should not be required to be repeated by all archs either.
My grumbling are general comments - and you may ignore these...
But, see below.
> diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
> index eafbc65..9c4a820 100644
> --- a/arch/sparc/mm/init_64.c
> +++ b/arch/sparc/mm/init_64.c
> @@ -2694,3 +2694,14 @@ void hugetlb_setup(struct pt_regs *regs)
> }
> }
> #endif
> +
> +#ifdef CONFIG_STRICT_DEVMEM
> +/* devmem_is_allowed for sparc.
> + */
> +int devmem_is_allowed(unsigned long pagenr)
> +{
> + int rc = page_is_ram(pagenr);
> +
> + return rc;
> +}
> +#endif
Any specific reason why this is sparc64 specific?
In the Kconfig.debug file you allow this to be sleected also for sparc32.
And I see no reason to restrict this to sparc64 as this is anyway optional.
Sam
--
To unsubscribe from this list: send the line "unsubscribe sparclinux" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
