Commit-ID: d878efce73fe86db34ddb2013260adf571a701a7 Gitweb: https://git.kernel.org/tip/d878efce73fe86db34ddb2013260adf571a701a7 Author: Joerg Roedel <jroe...@suse.de> AuthorDate: Wed, 8 Aug 2018 13:16:40 +0200 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Fri, 10 Aug 2018 21:12:45 +0200
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 <jroe...@suse.de> Signed-off-by: Thomas Gleixner <t...@linutronix.de> Cc: "H . Peter Anvin" <h...@zytor.com> Cc: linux...@kvack.org Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Andy Lutomirski <l...@kernel.org> Cc: Dave Hansen <dave.han...@intel.com> Cc: Josh Poimboeuf <jpoim...@redhat.com> Cc: Juergen Gross <jgr...@suse.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Borislav Petkov <b...@alien8.de> Cc: Jiri Kosina <jkos...@suse.cz> Cc: Boris Ostrovsky <boris.ostrov...@oracle.com> Cc: Brian Gerst <brge...@gmail.com> Cc: David Laight <david.lai...@aculab.com> Cc: Denys Vlasenko <dvlas...@redhat.com> Cc: Eduardo Valentin <edu...@amazon.com> Cc: Greg KH <gre...@linuxfoundation.org> Cc: Will Deacon <will.dea...@arm.com> Cc: aligu...@amazon.com Cc: daniel.gr...@iaik.tugraz.at Cc: hu...@google.com Cc: keesc...@google.com Cc: Andrea Arcangeli <aarca...@redhat.com> Cc: Waiman Long <ll...@redhat.com> Cc: Pavel Machek <pa...@ucw.cz> Cc: "David H . Gutteridge" <dhgutteri...@sympatico.ca> Cc: j...@8bytes.org Link: https://lkml.kernel.org/r/1533727000-9172-1-git-send-email-j...@8bytes.org --- arch/x86/include/asm/pgtable.h | 7 +++++-- arch/x86/mm/dump_pagetables.c | 6 +++--- arch/x86/mm/pti.c | 2 ++ 3 files changed, 10 insertions(+), 5 deletions(-) diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index e39088cb59ab..a1cb3339da8d 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -30,11 +30,14 @@ int __init __early_make_pgtable(unsigned long address, pmdval_t pmd); void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd); void ptdump_walk_pgd_level_debugfs(struct seq_file *m, pgd_t *pgd, bool user); void ptdump_walk_pgd_level_checkwx(void); +void ptdump_walk_user_pgd_level_checkwx(void); #ifdef CONFIG_DEBUG_WX -#define debug_checkwx() ptdump_walk_pgd_level_checkwx() +#define debug_checkwx() ptdump_walk_pgd_level_checkwx() +#define debug_checkwx_user() ptdump_walk_user_pgd_level_checkwx() #else -#define debug_checkwx() do { } while (0) +#define debug_checkwx() do { } while (0) +#define debug_checkwx_user() do { } while (0) #endif /* 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) diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c index 1dc5c683e7a5..d58b4aba9510 100644 --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -646,4 +646,6 @@ void pti_finalize(void) */ pti_clone_entry_text(); pti_clone_kernel_text(); + + debug_checkwx_user(); }
