4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Mark Rutland <mark.rutland@xxxxxxx>
commit 1d08a044cf12aee37dfd54837558e3295287b343 upstream.
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.
Fixes: 1404d6f13e47 ("arm64: dump: Add checking for writable and exectuable pages")
Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Laura Abbott <labbott@xxxxxxxxxx>
Reported-by: Timur Tabi <timur@xxxxxxxxxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/mm/dump.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- 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",