From d878efce73fe86db34ddb2013260adf571a701a7 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Wed, 8 Aug 2018 13:16:40 +0200 Subject: x86/mm/pti: Move user W+X check into pti_finalize() The user page-table gets the updated kernel mappings in pti_finalize(), which runs after the RO+X permissions got applied to the kernel page-table in mark_readonly(). But with CONFIG_DEBUG_WX enabled, the user page-table is already checked in mark_readonly() for insecure mappings. This causes false-positive warnings, because the user page-table did not get the updated mappings yet. Move the W+X check for the user page-table into pti_finalize() after it updated all required mappings. [ tglx: Folded !NX supported fix ] Signed-off-by: Joerg Roedel Signed-off-by: Thomas Gleixner Cc: "H . Peter Anvin" Cc: linux-mm@kvack.org Cc: Linus Torvalds Cc: Andy Lutomirski Cc: Dave Hansen Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Peter Zijlstra Cc: Borislav Petkov Cc: Jiri Kosina Cc: Boris Ostrovsky Cc: Brian Gerst Cc: David Laight Cc: Denys Vlasenko Cc: Eduardo Valentin Cc: Greg KH Cc: Will Deacon Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com Cc: Andrea Arcangeli Cc: Waiman Long Cc: Pavel Machek Cc: "David H . Gutteridge" Cc: joro@8bytes.org Link: https://lkml.kernel.org/r/1533727000-9172-1-git-send-email-joro@8bytes.org --- arch/x86/mm/dump_pagetables.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'arch/x86/mm/dump_pagetables.c') diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c index ccd92c4da57c..a12afff146d1 100644 --- a/arch/x86/mm/dump_pagetables.c +++ b/arch/x86/mm/dump_pagetables.c @@ -569,12 +569,13 @@ void ptdump_walk_pgd_level_debugfs(struct seq_file *m, pgd_t *pgd, bool user) } EXPORT_SYMBOL_GPL(ptdump_walk_pgd_level_debugfs); -static void ptdump_walk_user_pgd_level_checkwx(void) +void ptdump_walk_user_pgd_level_checkwx(void) { #ifdef CONFIG_PAGE_TABLE_ISOLATION pgd_t *pgd = INIT_PGD; - if (!static_cpu_has(X86_FEATURE_PTI)) + if (!(__supported_pte_mask & _PAGE_NX) || + !static_cpu_has(X86_FEATURE_PTI)) return; pr_info("x86/mm: Checking user space page tables\n"); @@ -586,7 +587,6 @@ static void ptdump_walk_user_pgd_level_checkwx(void) void ptdump_walk_pgd_level_checkwx(void) { ptdump_walk_pgd_level_core(NULL, NULL, true, false); - ptdump_walk_user_pgd_level_checkwx(); } static int __init pt_dump_init(void) -- cgit v1.2.3