From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753286AbdLDQ4b (ORCPT ); Mon, 4 Dec 2017 11:56:31 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:60688 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753122AbdLDQwA (ORCPT ); Mon, 4 Dec 2017 11:52:00 -0500 Message-Id: <20171204150609.673971250@linutronix.de> User-Agent: quilt/0.63-1 Date: Mon, 04 Dec 2017 15:08:05 +0100 From: Thomas Gleixner To: LKML Cc: x86@kernel.org, Linus Torvalds , Andy Lutomirsky , Peter Zijlstra , Dave Hansen , Borislav Petkov , Greg KH , keescook@google.com, hughd@google.com, Brian Gerst , Josh Poimboeuf , Denys Vlasenko , Rik van Riel , Boris Ostrovsky , Juergen Gross , David Laight , Eduardo Valentin , aliguori@amazon.com, Will Deacon , daniel.gruss@iaik.tugraz.at, moritz.lipp@iaik.tugraz.at, linux-mm@kvack.org, Dave Hansen , Borislav Petkov , michael.schwarz@iaik.tugraz.at, richard.fellner@student.tugraz.at Subject: [patch 59/60] x86/mm/dump_pagetables: Check user space page table for WX pages References: <20171204140706.296109558@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=x86-mm-dump_pagetables--Check_shadow_page_table_for_WX_pages.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Thomas Gleixner ptdump_walk_pgd_level_checkwx() checks the kernel page table for WX pages, but does not check the KERNEL_PAGE_TABLE_ISOLATION user space page table. Restructure the code so that dmesg output is selected by an explicit argument and not implicit via checking the pgd argument for !NULL. Add the check for the user space page table. Signed-off-by: Thomas Gleixner Cc: Rik van Riel Cc: keescook@google.com Cc: Denys Vlasenko Cc: moritz.lipp@iaik.tugraz.at Cc: linux-mm@kvack.org Cc: Peter Zijlstra Cc: Brian Gerst Cc: Dave Hansen Cc: hughd@google.com Cc: daniel.gruss@iaik.tugraz.at Cc: Borislav Petkov Cc: Andy Lutomirski Cc: Josh Poimboeuf Cc: michael.schwarz@iaik.tugraz.at Cc: Linus Torvalds Cc: richard.fellner@student.tugraz.at --- arch/x86/include/asm/pgtable.h | 1 + arch/x86/mm/debug_pagetables.c | 2 +- arch/x86/mm/dump_pagetables.c | 30 +++++++++++++++++++++++++----- 3 files changed, 27 insertions(+), 6 deletions(-) --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -28,6 +28,7 @@ extern pgd_t early_top_pgt[PTRS_PER_PGD] 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); void ptdump_walk_pgd_level_checkwx(void); #ifdef CONFIG_DEBUG_WX --- a/arch/x86/mm/debug_pagetables.c +++ b/arch/x86/mm/debug_pagetables.c @@ -5,7 +5,7 @@ static int ptdump_show(struct seq_file *m, void *v) { - ptdump_walk_pgd_level(m, NULL); + ptdump_walk_pgd_level_debugfs(m, NULL); return 0; } --- a/arch/x86/mm/dump_pagetables.c +++ b/arch/x86/mm/dump_pagetables.c @@ -447,7 +447,7 @@ static inline bool is_hypervisor_range(i } static void ptdump_walk_pgd_level_core(struct seq_file *m, pgd_t *pgd, - bool checkwx) + bool checkwx, bool dmesg) { #ifdef CONFIG_X86_64 pgd_t *start = (pgd_t *) &init_top_pgt; @@ -460,7 +460,7 @@ static void ptdump_walk_pgd_level_core(s if (pgd) { start = pgd; - st.to_dmesg = true; + st.to_dmesg = dmesg; } st.check_wx = checkwx; @@ -498,13 +498,33 @@ static void ptdump_walk_pgd_level_core(s void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd) { - ptdump_walk_pgd_level_core(m, pgd, false); + ptdump_walk_pgd_level_core(m, pgd, false, true); +} + +void ptdump_walk_pgd_level_debugfs(struct seq_file *m, pgd_t *pgd) +{ + ptdump_walk_pgd_level_core(m, pgd, false, false); +} +EXPORT_SYMBOL_GPL(ptdump_walk_pgd_level_debugfs); + +static void ptdump_walk_user_pgd_level_checkwx(void) +{ +#ifdef CONFIG_KERNEL_PAGE_TABLE_ISOLATION + pgd_t *pgd = (pgd_t *) &init_top_pgt; + + if (!static_cpu_has_bug(X86_BUG_CPU_SECURE_MODE_KPTI)) + return; + + pr_info("x86/mm: Checking user space page tables\n"); + pgd = kernel_to_user_pgdp(pgd); + ptdump_walk_pgd_level_core(NULL, pgd, true, false); +#endif } -EXPORT_SYMBOL_GPL(ptdump_walk_pgd_level); void ptdump_walk_pgd_level_checkwx(void) { - ptdump_walk_pgd_level_core(NULL, NULL, true); + ptdump_walk_pgd_level_core(NULL, NULL, true, false); + ptdump_walk_user_pgd_level_checkwx(); } static int __init pt_dump_init(void)