Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2993321AbbHHWNB (ORCPT ); Sat, 8 Aug 2015 18:13:01 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:36242 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2992749AbbHHWMo (ORCPT ); Sat, 8 Aug 2015 18:12:44 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexander Popov , Andrey Ryabinin , Alexander Potapenko , Andrey Konovalov , Borislav Petkov , Dmitry Vyukov , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , Ingo Molnar Subject: [PATCH 4.1 023/123] x86/kasan: Fix KASAN shadow region page tables Date: Sat, 8 Aug 2015 15:08:21 -0700 Message-Id: <20150808220718.711541729@linuxfoundation.org> X-Mailer: git-send-email 2.5.0 In-Reply-To: <20150808220717.771230091@linuxfoundation.org> References: <20150808220717.771230091@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6149 Lines: 198 4.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexander Popov commit 5d5aa3cfca5cf74cd928daf3674642e6004328d1 upstream. Currently KASAN shadow region page tables created without respect of physical offset (phys_base). This causes kernel halt when phys_base is not zero. So let's initialize KASAN shadow region page tables in kasan_early_init() using __pa_nodebug() which considers phys_base. This patch also separates x86_64_start_kernel() from KASAN low level details by moving kasan_map_early_shadow(init_level4_pgt) into kasan_early_init(). Remove the comment before clear_bss() which stopped bringing much profit to the code readability. Otherwise describing all the new order dependencies would be too verbose. Signed-off-by: Alexander Popov Signed-off-by: Andrey Ryabinin Cc: Alexander Potapenko Cc: Andrey Konovalov Cc: Borislav Petkov Cc: Dmitry Vyukov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1435828178-10975-3-git-send-email-a.ryabinin@samsung.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/kasan.h | 8 ++------ arch/x86/kernel/head64.c | 7 ++----- arch/x86/kernel/head_64.S | 29 ----------------------------- arch/x86/mm/kasan_init_64.c | 36 ++++++++++++++++++++++++++++++++++-- 4 files changed, 38 insertions(+), 42 deletions(-) --- a/arch/x86/include/asm/kasan.h +++ b/arch/x86/include/asm/kasan.h @@ -14,15 +14,11 @@ #ifndef __ASSEMBLY__ -extern pte_t kasan_zero_pte[]; -extern pte_t kasan_zero_pmd[]; -extern pte_t kasan_zero_pud[]; - #ifdef CONFIG_KASAN -void __init kasan_map_early_shadow(pgd_t *pgd); +void __init kasan_early_init(void); void __init kasan_init(void); #else -static inline void kasan_map_early_shadow(pgd_t *pgd) { } +static inline void kasan_early_init(void) { } static inline void kasan_init(void) { } #endif --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -161,13 +161,12 @@ asmlinkage __visible void __init x86_64_ /* Kill off the identity-map trampoline */ reset_early_page_tables(); - kasan_map_early_shadow(early_level4_pgt); - - /* clear bss before set_intr_gate with early_idt_handler */ clear_bss(); clear_page(init_level4_pgt); + kasan_early_init(); + for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) set_intr_gate(i, early_idt_handler_array[i]); load_idt((const struct desc_ptr *)&idt_descr); @@ -182,8 +181,6 @@ asmlinkage __visible void __init x86_64_ /* set init_level4_pgt kernel high mapping*/ init_level4_pgt[511] = early_level4_pgt[511]; - kasan_map_early_shadow(init_level4_pgt); - x86_64_start_reservations(real_mode_data); } --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -516,38 +516,9 @@ ENTRY(phys_base) /* This must match the first entry in level2_kernel_pgt */ .quad 0x0000000000000000 -#ifdef CONFIG_KASAN -#define FILL(VAL, COUNT) \ - .rept (COUNT) ; \ - .quad (VAL) ; \ - .endr - -NEXT_PAGE(kasan_zero_pte) - FILL(kasan_zero_page - __START_KERNEL_map + _KERNPG_TABLE, 512) -NEXT_PAGE(kasan_zero_pmd) - FILL(kasan_zero_pte - __START_KERNEL_map + _KERNPG_TABLE, 512) -NEXT_PAGE(kasan_zero_pud) - FILL(kasan_zero_pmd - __START_KERNEL_map + _KERNPG_TABLE, 512) - -#undef FILL -#endif - - #include "../../x86/xen/xen-head.S" __PAGE_ALIGNED_BSS NEXT_PAGE(empty_zero_page) .skip PAGE_SIZE -#ifdef CONFIG_KASAN -/* - * This page used as early shadow. We don't use empty_zero_page - * at early stages, stack instrumentation could write some garbage - * to this page. - * Latter we reuse it as zero shadow for large ranges of memory - * that allowed to access, but not instrumented by kasan - * (vmalloc/vmemmap ...). - */ -NEXT_PAGE(kasan_zero_page) - .skip PAGE_SIZE -#endif --- a/arch/x86/mm/kasan_init_64.c +++ b/arch/x86/mm/kasan_init_64.c @@ -11,7 +11,19 @@ extern pgd_t early_level4_pgt[PTRS_PER_PGD]; extern struct range pfn_mapped[E820_X_MAX]; -extern unsigned char kasan_zero_page[PAGE_SIZE]; +static pud_t kasan_zero_pud[PTRS_PER_PUD] __page_aligned_bss; +static pmd_t kasan_zero_pmd[PTRS_PER_PMD] __page_aligned_bss; +static pte_t kasan_zero_pte[PTRS_PER_PTE] __page_aligned_bss; + +/* + * This page used as early shadow. We don't use empty_zero_page + * at early stages, stack instrumentation could write some garbage + * to this page. + * Latter we reuse it as zero shadow for large ranges of memory + * that allowed to access, but not instrumented by kasan + * (vmalloc/vmemmap ...). + */ +static unsigned char kasan_zero_page[PAGE_SIZE] __page_aligned_bss; static int __init map_range(struct range *range) { @@ -36,7 +48,7 @@ static void __init clear_pgds(unsigned l pgd_clear(pgd_offset_k(start)); } -void __init kasan_map_early_shadow(pgd_t *pgd) +static void __init kasan_map_early_shadow(pgd_t *pgd) { int i; unsigned long start = KASAN_SHADOW_START; @@ -166,6 +178,26 @@ static struct notifier_block kasan_die_n }; #endif +void __init kasan_early_init(void) +{ + int i; + pteval_t pte_val = __pa_nodebug(kasan_zero_page) | __PAGE_KERNEL; + pmdval_t pmd_val = __pa_nodebug(kasan_zero_pte) | _KERNPG_TABLE; + pudval_t pud_val = __pa_nodebug(kasan_zero_pmd) | _KERNPG_TABLE; + + for (i = 0; i < PTRS_PER_PTE; i++) + kasan_zero_pte[i] = __pte(pte_val); + + for (i = 0; i < PTRS_PER_PMD; i++) + kasan_zero_pmd[i] = __pmd(pmd_val); + + for (i = 0; i < PTRS_PER_PUD; i++) + kasan_zero_pud[i] = __pud(pud_val); + + kasan_map_early_shadow(early_level4_pgt); + kasan_map_early_shadow(init_level4_pgt); +} + void __init kasan_init(void) { int i; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/