APPLIED[A]: [PATCH][SRU Artful] arm64: fix CONFIG_DEBUG_WX address reporting

[Stefan Bader]

On 21.04.2018 00:05, dann frazier wrote:
> From: Mark Rutland <mark.rutland at arm.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1765850
> 
> In ptdump_check_wx(), we pass walk_pgd() a start address of 0 (rather
> than VA_START) for the init_mm. This means that any reported W&X
> addresses are offset by VA_START, which is clearly wrong and can make
> them appear like userspace addresses.
> 
> Fix this by telling the ptdump code that we're walking init_mm starting
> at VA_START. We don't need to update the addr_markers, since these are
> still valid bounds regardless.
> 
> Cc: <stable at vger.kernel.org>
> Fixes: 1404d6f13e47 ("arm64: dump: Add checking for writable and exectuable pages")
> Signed-off-by: Mark Rutland <mark.rutland at arm.com>
> Cc: Kees Cook <keescook at chromium.org>
> Cc: Laura Abbott <labbott at redhat.com>
> Reported-by: Timur Tabi <timur at codeaurora.org>
> Signed-off-by: Will Deacon <will.deacon at arm.com>
> (cherry picked from commit 1d08a044cf12aee37dfd54837558e3295287b343)
> Signed-off-by: dann frazier <dann.frazier at canonical.com>
> ---

Applied to artful/master-next
>  arch/arm64/mm/dump.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/mm/dump.c b/arch/arm64/mm/dump.c
> index ca74a2aace42..7b60d62ac593 100644
> --- a/arch/arm64/mm/dump.c
> +++ b/arch/arm64/mm/dump.c
> @@ -389,7 +389,7 @@ void ptdump_check_wx(void)
>  		.check_wx = true,
>  	};
>  
> -	walk_pgd(&st, &init_mm, 0);
> +	walk_pgd(&st, &init_mm, VA_START);
>  	note_page(&st, 0, 0, 0);
>  	if (st.wx_pages || st.uxn_pages)
>  		pr_warn("Checked W+X mappings: FAILED, %lu W+X pages found, %lu non-UXN pages found\n",
> 


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