4.14-stable review patch. If anyone has any objections, please let me know.
------------------ From: Mark Rutland <[email protected]> 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 <[email protected]> Cc: Kees Cook <[email protected]> Cc: Laura Abbott <[email protected]> Reported-by: Timur Tabi <[email protected]> Signed-off-by: Will Deacon <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- 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",
