diff options
| -rw-r--r-- | arch/x86/mm/kasan_init_64.c | 123 | ||||
| -rw-r--r-- | include/linux/kasan.h | 9 | ||||
| -rw-r--r-- | mm/kasan/Makefile | 2 | ||||
| -rw-r--r-- | mm/kasan/kasan_init.c | 152 |
4 files changed, 167 insertions, 119 deletions
diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c index e1840f3db5b5..9ce5da27b136 100644 --- a/arch/x86/mm/kasan_init_64.c +++ b/arch/x86/mm/kasan_init_64.c @@ -12,20 +12,6 @@ extern pgd_t early_level4_pgt[PTRS_PER_PGD]; extern struct range pfn_mapped[E820_X_MAX]; -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) { unsigned long start; @@ -62,106 +48,6 @@ static void __init kasan_map_early_shadow(pgd_t *pgd) } } -static int __init zero_pte_populate(pmd_t *pmd, unsigned long addr, - unsigned long end) -{ - pte_t *pte = pte_offset_kernel(pmd, addr); - - while (addr + PAGE_SIZE <= end) { - WARN_ON(!pte_none(*pte)); - set_pte(pte, __pte(__pa_nodebug(kasan_zero_page) - | __PAGE_KERNEL_RO)); - addr += PAGE_SIZE; - pte = pte_offset_kernel(pmd, addr); - } - return 0; -} - -static int __init zero_pmd_populate(pud_t *pud, unsigned long addr, - unsigned long end) -{ - int ret = 0; - pmd_t *pmd = pmd_offset(pud, addr); - - while (IS_ALIGNED(addr, PMD_SIZE) && addr + PMD_SIZE <= end) { - WARN_ON(!pmd_none(*pmd)); - set_pmd(pmd, __pmd(__pa_nodebug(kasan_zero_pte) - | _KERNPG_TABLE)); - addr += PMD_SIZE; - pmd = pmd_offset(pud, addr); - } - if (addr < end) { - if (pmd_none(*pmd)) { - void *p = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE); - if (!p) - return -ENOMEM; - set_pmd(pmd, __pmd(__pa_nodebug(p) | _KERNPG_TABLE)); - } - ret = zero_pte_populate(pmd, addr, end); - } - return ret; -} - - -static int __init zero_pud_populate(pgd_t *pgd, unsigned long addr, - unsigned long end) -{ - int ret = 0; - pud_t *pud = pud_offset(pgd, addr); - - while (IS_ALIGNED(addr, PUD_SIZE) && addr + PUD_SIZE <= end) { - WARN_ON(!pud_none(*pud)); - set_pud(pud, __pud(__pa_nodebug(kasan_zero_pmd) - | _KERNPG_TABLE)); - addr += PUD_SIZE; - pud = pud_offset(pgd, addr); - } - - if (addr < end) { - if (pud_none(*pud)) { - void *p = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE); - if (!p) - return -ENOMEM; - set_pud(pud, __pud(__pa_nodebug(p) | _KERNPG_TABLE)); - } - ret = zero_pmd_populate(pud, addr, end); - } - return ret; -} - -static int __init zero_pgd_populate(unsigned long addr, unsigned long end) -{ - int ret = 0; - pgd_t *pgd = pgd_offset_k(addr); - - while (IS_ALIGNED(addr, PGDIR_SIZE) && addr + PGDIR_SIZE <= end) { - WARN_ON(!pgd_none(*pgd)); - set_pgd(pgd, __pgd(__pa_nodebug(kasan_zero_pud) - | _KERNPG_TABLE)); - addr += PGDIR_SIZE; - pgd = pgd_offset_k(addr); - } - - if (addr < end) { - if (pgd_none(*pgd)) { - void *p = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE); - if (!p) - return -ENOMEM; - set_pgd(pgd, __pgd(__pa_nodebug(p) | _KERNPG_TABLE)); - } - ret = zero_pud_populate(pgd, addr, end); - } - return ret; -} - - -static void __init populate_zero_shadow(const void *start, const void *end) -{ - if (zero_pgd_populate((unsigned long)start, (unsigned long)end)) - panic("kasan: unable to map zero shadow!"); -} - - #ifdef CONFIG_KASAN_INLINE static int kasan_die_handler(struct notifier_block *self, unsigned long val, @@ -213,7 +99,7 @@ void __init kasan_init(void) clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END); - populate_zero_shadow((void *)KASAN_SHADOW_START, + kasan_populate_zero_shadow((void *)KASAN_SHADOW_START, kasan_mem_to_shadow((void *)PAGE_OFFSET)); for (i = 0; i < E820_X_MAX; i++) { @@ -223,14 +109,15 @@ void __init kasan_init(void) if (map_range(&pfn_mapped[i])) panic("kasan: unable to allocate shadow!"); } - populate_zero_shadow(kasan_mem_to_shadow((void *)PAGE_OFFSET + MAXMEM), - kasan_mem_to_shadow((void *)__START_KERNEL_map)); + kasan_populate_zero_shadow( + kasan_mem_to_shadow((void *)PAGE_OFFSET + MAXMEM), + kasan_mem_to_shadow((void *)__START_KERNEL_map)); vmemmap_populate((unsigned long)kasan_mem_to_shadow(_stext), (unsigned long)kasan_mem_to_shadow(_end), NUMA_NO_NODE); - populate_zero_shadow(kasan_mem_to_shadow((void *)MODULES_END), + kasan_populate_zero_shadow(kasan_mem_to_shadow((void *)MODULES_END), (void *)KASAN_SHADOW_END); memset(kasan_zero_page, 0, PAGE_SIZE); diff --git a/include/linux/kasan.h b/include/linux/kasan.h index 6fb1c7d4292c..4b9f85c963d0 100644 --- a/include/linux/kasan.h +++ b/include/linux/kasan.h @@ -12,8 +12,17 @@ struct vm_struct; #define KASAN_SHADOW_SCALE_SHIFT 3 #include <asm/kasan.h> +#include <asm/pgtable.h> #include <linux/sched.h> +extern unsigned char kasan_zero_page[PAGE_SIZE]; +extern pte_t kasan_zero_pte[PTRS_PER_PTE]; +extern pmd_t kasan_zero_pmd[PTRS_PER_PMD]; +extern pud_t kasan_zero_pud[PTRS_PER_PUD]; + +void kasan_populate_zero_shadow(const void *shadow_start, + const void *shadow_end); + static inline void *kasan_mem_to_shadow(const void *addr) { return (void *)((unsigned long)addr >> KASAN_SHADOW_SCALE_SHIFT) diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile index bd837b8c2f41..64710148941e 100644 --- a/mm/kasan/Makefile +++ b/mm/kasan/Makefile @@ -5,4 +5,4 @@ CFLAGS_REMOVE_kasan.o = -pg # see: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63533 CFLAGS_kasan.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -obj-y := kasan.o report.o +obj-y := kasan.o report.o kasan_init.o diff --git a/mm/kasan/kasan_init.c b/mm/kasan/kasan_init.c new file mode 100644 index 000000000000..3f9a41cf0ac6 --- /dev/null +++ b/mm/kasan/kasan_init.c @@ -0,0 +1,152 @@ +/* + * This file contains some kasan initialization code. + * + * Copyright (c) 2015 Samsung Electronics Co., Ltd. + * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ + +#include <linux/bootmem.h> +#include <linux/init.h> +#include <linux/kasan.h> +#include <linux/kernel.h> +#include <linux/memblock.h> +#include <linux/pfn.h> + +#include <asm/page.h> +#include <asm/pgalloc.h> + +/* + * This page serves two purposes: + * - It used as early shadow memory. The entire shadow region populated + * with this page, before we will be able to setup normal shadow memory. + * - Latter it reused it as zero shadow to cover large ranges of memory + * that allowed to access, but not handled by kasan (vmalloc/vmemmap ...). + */ +unsigned char kasan_zero_page[PAGE_SIZE] __page_aligned_bss; + +#if CONFIG_PGTABLE_LEVELS > 3 +pud_t kasan_zero_pud[PTRS_PER_PUD] __page_aligned_bss; +#endif +#if CONFIG_PGTABLE_LEVELS > 2 +pmd_t kasan_zero_pmd[PTRS_PER_PMD] __page_aligned_bss; +#endif +pte_t kasan_zero_pte[PTRS_PER_PTE] __page_aligned_bss; + +static __init void *early_alloc(size_t size, int node) +{ + return memblock_virt_alloc_try_nid(size, size, __pa(MAX_DMA_ADDRESS), + BOOTMEM_ALLOC_ACCESSIBLE, node); +} + +static void __init zero_pte_populate(pmd_t *pmd, unsigned long addr, + unsigned long end) +{ + pte_t *pte = pte_offset_kernel(pmd, addr); + pte_t zero_pte; + + zero_pte = pfn_pte(PFN_DOWN(__pa(kasan_zero_page)), PAGE_KERNEL); + zero_pte = pte_wrprotect(zero_pte); + + while (addr + PAGE_SIZE <= end) { + set_pte_at(&init_mm, addr, pte, zero_pte); + addr += PAGE_SIZE; + pte = pte_offset_kernel(pmd, addr); + } +} + +static void __init zero_pmd_populate(pud_t *pud, unsigned long addr, + unsigned long end) +{ + pmd_t *pmd = pmd_offset(pud, addr); + unsigned long next; + + do { + next = pmd_addr_end(addr, end); + + if (IS_ALIGNED(addr, PMD_SIZE) && end - addr >= PMD_SIZE) { + pmd_populate_kernel(&init_mm, pmd, kasan_zero_pte); + continue; + } + + if (pmd_none(*pmd)) { + pmd_populate_kernel(&init_mm, pmd, + early_alloc(PAGE_SIZE, NUMA_NO_NODE)); + } + zero_pte_populate(pmd, addr, next); + } while (pmd++, addr = next, addr != end); +} + +static void __init zero_pud_populate(pgd_t *pgd, unsigned long addr, + unsigned long end) +{ + pud_t *pud = pud_offset(pgd, addr); + unsigned long next; + + do { + next = pud_addr_end(addr, end); + if (IS_ALIGNED(addr, PUD_SIZE) && end - addr >= PUD_SIZE) { + pmd_t *pmd; + + pud_populate(&init_mm, pud, kasan_zero_pmd); + pmd = pmd_offset(pud, addr); + pmd_populate_kernel(&init_mm, pmd, kasan_zero_pte); + continue; + } + + if (pud_none(*pud)) { + pud_populate(&init_mm, pud, + early_alloc(PAGE_SIZE, NUMA_NO_NODE)); + } + zero_pmd_populate(pud, addr, next); + } while (pud++, addr = next, addr != end); +} + +/** + * kasan_populate_zero_shadow - populate shadow memory region with + * kasan_zero_page + * @shadow_start - start of the memory range to populate + * @shadow_end - end of the memory range to populate + */ +void __init kasan_populate_zero_shadow(const void *shadow_start, + const void *shadow_end) +{ + unsigned long addr = (unsigned long)shadow_start; + unsigned long end = (unsigned long)shadow_end; + pgd_t *pgd = pgd_offset_k(addr); + unsigned long next; + + do { + next = pgd_addr_end(addr, end); + + if (IS_ALIGNED(addr, PGDIR_SIZE) && end - addr >= PGDIR_SIZE) { + pud_t *pud; + pmd_t *pmd; + + /* + * kasan_zero_pud should be populated with pmds + * at this moment. + * [pud,pmd]_populate*() below needed only for + * 3,2 - level page tables where we don't have + * puds,pmds, so pgd_populate(), pud_populate() + * is noops. + */ + pgd_populate(&init_mm, pgd, kasan_zero_pud); + pud = pud_offset(pgd, addr); + pud_populate(&init_mm, pud, kasan_zero_pmd); + pmd = pmd_offset(pud, addr); + pmd_populate_kernel(&init_mm, pmd, kasan_zero_pte); + continue; + } + + if (pgd_none(*pgd)) { + pgd_populate(&init_mm, pgd, + early_alloc(PAGE_SIZE, NUMA_NO_NODE)); + } + zero_pud_populate(pgd, addr, next); + } while (pgd++, addr = next, addr != end); +} |