diff options
| -rw-r--r-- | Makefile | 6 | ||||
| -rw-r--r-- | common/Makefile | 1 | ||||
| -rw-r--r-- | common/tlsf.c | 29 | ||||
| -rw-r--r-- | include/linux/kasan.h | 89 | ||||
| -rw-r--r-- | lib/Kconfig | 2 | ||||
| -rw-r--r-- | lib/Makefile | 1 | ||||
| -rw-r--r-- | lib/kasan/Kconfig | 16 | ||||
| -rw-r--r-- | lib/kasan/Makefile | 14 | ||||
| -rw-r--r-- | lib/kasan/common.c | 108 | ||||
| -rw-r--r-- | lib/kasan/generic.c | 315 | ||||
| -rw-r--r-- | lib/kasan/generic_report.c | 150 | ||||
| -rw-r--r-- | lib/kasan/kasan.h | 164 | ||||
| -rw-r--r-- | lib/kasan/report.c | 199 | ||||
| -rw-r--r-- | lib/string.c | 3 | ||||
| -rw-r--r-- | scripts/Makefile.kasan | 17 | ||||
| -rw-r--r-- | scripts/Makefile.lib | 10 |
16 files changed, 1117 insertions, 7 deletions
@@ -448,6 +448,7 @@ export LDFLAGS_barebox export LDFLAGS_pbl export CFLAGS_UBSAN +export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE # Files to ignore in find ... statements @@ -636,7 +637,10 @@ KBUILD_CFLAGS += $(call cc-option,-Wno-pointer-sign,) # change __FILE__ to the relative path from the srctree KBUILD_CFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=) -include $(srctree)/scripts/Makefile.ubsan +include-y +=scripts/Makefile.ubsan +include-$(CONFIG_KASAN) += scripts/Makefile.kasan + +include $(addprefix $(srctree)/, $(include-y)) # KBUILD_IMAGE: Default barebox image to build # Depending on the architecture, this can be either compressed or not. diff --git a/common/Makefile b/common/Makefile index ad5146a301..faf0415ef3 100644 --- a/common/Makefile +++ b/common/Makefile @@ -38,6 +38,7 @@ obj-$(CONFIG_GREGORIAN_CALENDER) += date.o obj-$(CONFIG_KALLSYMS) += kallsyms.o obj-$(CONFIG_MALLOC_DLMALLOC) += dlmalloc.o obj-$(CONFIG_MALLOC_TLSF) += tlsf_malloc.o tlsf.o calloc.o +KASAN_SANITIZE_tlsf.o := n obj-$(CONFIG_MALLOC_DUMMY) += dummy_malloc.o calloc.o obj-$(CONFIG_MEMINFO) += meminfo.o obj-$(CONFIG_MENU) += menu.o diff --git a/common/tlsf.c b/common/tlsf.c index 86cc684ab6..4247a9d3c7 100644 --- a/common/tlsf.c +++ b/common/tlsf.c @@ -3,9 +3,14 @@ #include <string.h> #include <tlsf.h> #include "tlsfbits.h" +#include <linux/kasan.h> #define CHAR_BIT 8 +#ifndef CONFIG_KASAN +#define __memcpy memcpy +#endif + /* ** Constants. */ @@ -529,7 +534,7 @@ static void block_trim_free(control_t* control, block_header_t* block, size_t si } /* Trim any trailing block space off the end of a used block, return to pool. */ -static void block_trim_used(control_t* control, block_header_t* block, size_t size) +static void block_trim_used(control_t* control, block_header_t* block, size_t size, size_t used) { tlsf_assert(!block_is_free(block) && "block must be used"); if (block_can_split(block, size)) @@ -541,6 +546,10 @@ static void block_trim_used(control_t* control, block_header_t* block, size_t si remaining_block = block_merge_next(control, remaining_block); block_insert(control, remaining_block); } + + kasan_poison_shadow(&block->size, size + 2 * sizeof(size_t), + KASAN_KMALLOC_REDZONE); + kasan_unpoison_shadow(block_to_ptr(block), used); } static block_header_t* block_trim_free_leading(control_t* control, block_header_t* block, size_t size) @@ -589,7 +598,8 @@ static block_header_t* block_locate_free(control_t* control, size_t size) return block; } -static void* block_prepare_used(control_t* control, block_header_t* block, size_t size) +static void* block_prepare_used(control_t* control, block_header_t* block, + size_t size, size_t used) { void* p = 0; if (block) @@ -598,6 +608,10 @@ static void* block_prepare_used(control_t* control, block_header_t* block, size_ block_trim_free(control, block, size); block_mark_as_used(block); p = block_to_ptr(block); + + kasan_poison_shadow(&block->size, size + 2 * sizeof(size_t), + KASAN_KMALLOC_REDZONE); + kasan_unpoison_shadow(p, used); } return p; } @@ -907,6 +921,7 @@ tlsf_t tlsf_create_with_pool(void* mem, size_t bytes) { tlsf_t tlsf = tlsf_create(mem); tlsf_add_pool(tlsf, (char*)mem + tlsf_size(), bytes - tlsf_size()); + kasan_poison_shadow(mem, bytes, KASAN_TAG_INVALID); return tlsf; } @@ -926,7 +941,8 @@ void* tlsf_malloc(tlsf_t tlsf, size_t size) control_t* control = tlsf_cast(control_t*, tlsf); const size_t adjust = adjust_request_size(size, ALIGN_SIZE); block_header_t* block = block_locate_free(control, adjust); - return block_prepare_used(control, block, adjust); + + return block_prepare_used(control, block, adjust, size); } void* tlsf_memalign(tlsf_t tlsf, size_t align, size_t size) @@ -983,7 +999,7 @@ void* tlsf_memalign(tlsf_t tlsf, size_t align, size_t size) } } - return block_prepare_used(control, block, adjust); + return block_prepare_used(control, block, adjust, size); } void tlsf_free(tlsf_t tlsf, void* ptr) @@ -994,6 +1010,7 @@ void tlsf_free(tlsf_t tlsf, void* ptr) control_t* control = tlsf_cast(control_t*, tlsf); block_header_t* block = block_from_ptr(ptr); tlsf_assert(!block_is_free(block) && "block already marked as free"); + kasan_poison_shadow(ptr, block_size(block), 0xff); block_mark_as_free(block); block = block_merge_prev(control, block); block = block_merge_next(control, block); @@ -1050,7 +1067,7 @@ void* tlsf_realloc(tlsf_t tlsf, void* ptr, size_t size) if (p) { const size_t minsize = tlsf_min(cursize, size); - memcpy(p, ptr, minsize); + __memcpy(p, ptr, minsize); tlsf_free(tlsf, ptr); } } @@ -1064,7 +1081,7 @@ void* tlsf_realloc(tlsf_t tlsf, void* ptr, size_t size) } /* Trim the resulting block and return the original pointer. */ - block_trim_used(control, block, adjust); + block_trim_used(control, block, adjust, size); p = ptr; } } diff --git a/include/linux/kasan.h b/include/linux/kasan.h new file mode 100644 index 0000000000..7c184cd0e2 --- /dev/null +++ b/include/linux/kasan.h @@ -0,0 +1,89 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_KASAN_H +#define _LINUX_KASAN_H + +#include <linux/types.h> + +/* + * On 64bit architectures tlsf aligns all allocations to a 64bit + * boundary, otherwise they are only 32bit aligned. + */ +#ifdef CONFIG_64BIT +#define KASAN_SHADOW_SCALE_SHIFT 3 +#else +#define KASAN_SHADOW_SCALE_SHIFT 2 +#endif + +#define KASAN_TAG_KERNEL 0xFF /* native kernel pointers tag */ +#define KASAN_TAG_INVALID 0xFE /* inaccessible memory tag */ +#define KASAN_TAG_MAX 0xFD /* maximum value for random tags */ + +#define KASAN_FREE_PAGE 0xFF /* page was freed */ +#define KASAN_PAGE_REDZONE 0xFE /* redzone for kmalloc_large allocations */ +#define KASAN_KMALLOC_REDZONE 0xFC /* redzone inside slub object */ +#define KASAN_KMALLOC_FREE 0xFB /* object was freed (kmem_cache_free/kfree) */ +#define KASAN_KMALLOC_FREETRACK 0xFA /* object was freed and has free track set */ + +#define KASAN_GLOBAL_REDZONE 0xF9 /* redzone for global variable */ +#define KASAN_VMALLOC_INVALID 0xF8 /* unallocated space in vmapped page */ + +/* + * Stack redzone shadow values + * (Those are compiler's ABI, don't change them) + */ +#define KASAN_STACK_LEFT 0xF1 +#define KASAN_STACK_MID 0xF2 +#define KASAN_STACK_RIGHT 0xF3 +#define KASAN_STACK_PARTIAL 0xF4 + +/* + * alloca redzone shadow values + */ +#define KASAN_ALLOCA_LEFT 0xCA +#define KASAN_ALLOCA_RIGHT 0xCB + +#ifdef CONFIG_KASAN + +extern unsigned long kasan_shadow_start; +extern unsigned long kasan_shadow_base; + +static inline void *kasan_mem_to_shadow(const void *addr) +{ + unsigned long a = (unsigned long)addr; + + a -= kasan_shadow_start; + a >>= KASAN_SHADOW_SCALE_SHIFT; + a += kasan_shadow_base; + + return (void *)a; +} + +void kasan_init(unsigned long membase, unsigned long memsize, + unsigned long shadow_base); + +/* Enable reporting bugs after kasan_disable_current() */ +extern void kasan_enable_current(void); + +/* Disable reporting bugs for current task */ +extern void kasan_disable_current(void); + +void kasan_poison_shadow(const void *address, size_t size, u8 value); +void kasan_unpoison_shadow(const void *address, size_t size); + +bool kasan_save_enable_multi_shot(void); +void kasan_restore_multi_shot(bool enabled); + +#else /* CONFIG_KASAN */ + +static inline void kasan_poison_shadow(const void *address, size_t size, u8 value) {} +static inline void kasan_unpoison_shadow(const void *address, size_t size) {} + +static inline void kasan_enable_current(void) {} +static inline void kasan_disable_current(void) {} + +static inline void kasan_init(unsigned long membase, unsigned long memsize, + unsigned long shadow_base) {} + +#endif /* CONFIG_KASAN */ + +#endif /* LINUX_KASAN_H */ diff --git a/lib/Kconfig b/lib/Kconfig index 90552f3c27..6d909c1ac8 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -154,6 +154,8 @@ source "lib/logo/Kconfig" source "lib/bootstrap/Kconfig" +source "lib/kasan/Kconfig" + config PRINTF_UUID bool diff --git a/lib/Makefile b/lib/Makefile index 73399a1bf1..ba6af6f2ab 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -7,6 +7,7 @@ obj-y += string.o obj-y += strtox.o obj-y += kstrtox.o obj-y += vsprintf.o +obj-$(CONFIG_KASAN) += kasan/ pbl-$(CONFIG_PBL_CONSOLE) += vsprintf.o obj-y += div64.o pbl-y += div64.o diff --git a/lib/kasan/Kconfig b/lib/kasan/Kconfig new file mode 100644 index 0000000000..7a18cf95be --- /dev/null +++ b/lib/kasan/Kconfig @@ -0,0 +1,16 @@ +source "scripts/Kconfig.include" + +config HAVE_ARCH_KASAN + bool + +config CC_HAS_KASAN_GENERIC + def_bool $(cc-option, -fsanitize=kernel-address) + +config KASAN + bool "KASAN: runtime memory debugger" + depends on (HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC) + depends on MALLOC_TLSF + select CONSTRUCTORS + help + Enables KASAN (KernelAddressSANitizer) - runtime memory debugger, + designed to find out-of-bounds accesses and use-after-free bugs. diff --git a/lib/kasan/Makefile b/lib/kasan/Makefile new file mode 100644 index 0000000000..31e9d890d5 --- /dev/null +++ b/lib/kasan/Makefile @@ -0,0 +1,14 @@ + +obj-y += generic_report.o generic.o report.o common.o test_kasan.o +KASAN_SANITIZE_generic_report.o := n +KASAN_SANITIZE_generic.o := n +KASAN_SANITIZE_report.o := n +KASAN_SANITIZE_common.o := n + +CC_FLAGS_KASAN_RUNTIME := $(call cc-option, -fno-conserve-stack) +CC_FLAGS_KASAN_RUNTIME += -fno-stack-protector + +CFLAGS_generic_report.o := $(CC_FLAGS_KASAN_RUNTIME) +CFLAGS_generic.o := $(CC_FLAGS_KASAN_RUNTIME) +CFLAGS_report.o := $(CC_FLAGS_KASAN_RUNTIME) +CFLAGS_common.o := $(CC_FLAGS_KASAN_RUNTIME) diff --git a/lib/kasan/common.c b/lib/kasan/common.c new file mode 100644 index 0000000000..1ebf66a7b8 --- /dev/null +++ b/lib/kasan/common.c @@ -0,0 +1,108 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This file contains common generic and tag-based KASAN code. + * + * Copyright (c) 2014 Samsung Electronics Co., Ltd. + * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com> + * + * Some code borrowed from https://github.com/xairy/kasan-prototype by + * Andrey Konovalov <andreyknvl@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 <common.h> +#include <linux/kasan.h> +#include <linux/kernel.h> + +#include "kasan.h" + +int kasan_depth; + +void kasan_enable_current(void) +{ + kasan_depth++; +} + +void kasan_disable_current(void) +{ + kasan_depth--; +} + +#undef memset +void *memset(void *addr, int c, size_t len) +{ + if (!check_memory_region((unsigned long)addr, len, true, _RET_IP_)) + return NULL; + + return __memset(addr, c, len); +} + +#ifdef __HAVE_ARCH_MEMMOVE +#undef memmove +void *memmove(void *dest, const void *src, size_t len) +{ + if (!check_memory_region((unsigned long)src, len, false, _RET_IP_) || + !check_memory_region((unsigned long)dest, len, true, _RET_IP_)) + return NULL; + + return __memmove(dest, src, len); +} +#endif + +#undef memcpy +void *memcpy(void *dest, const void *src, size_t len) +{ + if (!check_memory_region((unsigned long)src, len, false, _RET_IP_) || + !check_memory_region((unsigned long)dest, len, true, _RET_IP_)) + return NULL; + + return __memcpy(dest, src, len); +} + +/* + * Poisons the shadow memory for 'size' bytes starting from 'addr'. + * Memory addresses should be aligned to KASAN_SHADOW_SCALE_SIZE. + */ +void kasan_poison_shadow(const void *address, size_t size, u8 value) +{ + void *shadow_start, *shadow_end; + + /* + * Perform shadow offset calculation based on untagged address, as + * some of the callers (e.g. kasan_poison_object_data) pass tagged + * addresses to this function. + */ + address = reset_tag(address); + + shadow_start = kasan_mem_to_shadow(address); + shadow_end = kasan_mem_to_shadow(address + size); + + __memset(shadow_start, value, shadow_end - shadow_start); +} + +void kasan_unpoison_shadow(const void *address, size_t size) +{ + u8 tag = get_tag(address); + + /* + * Perform shadow offset calculation based on untagged address, as + * some of the callers (e.g. kasan_unpoison_object_data) pass tagged + * addresses to this function. + */ + address = reset_tag(address); + + kasan_poison_shadow(address, size, tag); + + if (size & KASAN_SHADOW_MASK) { + u8 *shadow = (u8 *)kasan_mem_to_shadow(address + size); + + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS)) + *shadow = tag; + else + *shadow = size & KASAN_SHADOW_MASK; + } +} diff --git a/lib/kasan/generic.c b/lib/kasan/generic.c new file mode 100644 index 0000000000..b33a6c1a6c --- /dev/null +++ b/lib/kasan/generic.c @@ -0,0 +1,315 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This file contains core generic KASAN code. + * + * Copyright (c) 2014 Samsung Electronics Co., Ltd. + * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com> + * + * Some code borrowed from https://github.com/xairy/kasan-prototype by + * Andrey Konovalov <andreyknvl@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. + * + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <common.h> + +#include "kasan.h" + +unsigned long kasan_shadow_start; +unsigned long kasan_shadow_base; + +/* + * All functions below always inlined so compiler could + * perform better optimizations in each of __asan_loadX/__assn_storeX + * depending on memory access size X. + */ + +static __always_inline bool memory_is_poisoned_1(unsigned long addr) +{ + s8 shadow_value = *(s8 *)kasan_mem_to_shadow((void *)addr); + + if (unlikely(shadow_value)) { + s8 last_accessible_byte = addr & KASAN_SHADOW_MASK; + return unlikely(last_accessible_byte >= shadow_value); + } + + return false; +} + +static __always_inline bool memory_is_poisoned_2_4_8(unsigned long addr, + unsigned long size) +{ + u8 *shadow_addr = (u8 *)kasan_mem_to_shadow((void *)addr); + + /* + * Access crosses 8(shadow size)-byte boundary. Such access maps + * into 2 shadow bytes, so we need to check them both. + */ + if (unlikely(((addr + size - 1) & KASAN_SHADOW_MASK) < size - 1)) + return *shadow_addr || memory_is_poisoned_1(addr + size - 1); + + return memory_is_poisoned_1(addr + size - 1); +} + +static __always_inline bool memory_is_poisoned_16(unsigned long addr) +{ + u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr); + + /* Unaligned 16-bytes access maps into 3 shadow bytes. */ + if (unlikely(!IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE))) + return *shadow_addr || memory_is_poisoned_1(addr + 15); + + return *shadow_addr; +} + +static __always_inline unsigned long bytes_is_nonzero(const u8 *start, + size_t size) +{ + while (size) { + if (unlikely(*start)) + return (unsigned long)start; + start++; + size--; + } + + return 0; +} + +static __always_inline unsigned long memory_is_nonzero(const void *start, + const void *end) +{ + unsigned int words; + unsigned long ret; + unsigned int prefix = (unsigned long)start % 8; + + if (end - start <= 16) + return bytes_is_nonzero(start, end - start); + + if (prefix) { + prefix = 8 - prefix; + ret = bytes_is_nonzero(start, prefix); + if (unlikely(ret)) + return ret; + start += prefix; + } + + words = (end - start) / 8; + while (words) { + if (unlikely(*(u64 *)start)) + return bytes_is_nonzero(start, 8); + start += 8; + words--; + } + + return bytes_is_nonzero(start, (end - start) % 8); +} + +static __always_inline bool memory_is_poisoned_n(unsigned long addr, + size_t size) +{ + unsigned long ret; + + ret = memory_is_nonzero(kasan_mem_to_shadow((void *)addr), + kasan_mem_to_shadow((void *)addr + size - 1) + 1); + + if (unlikely(ret)) { + unsigned long last_byte = addr + size - 1; + s8 *last_shadow = (s8 *)kasan_mem_to_shadow((void *)last_byte); + + if (unlikely(ret != (unsigned long)last_shadow || + ((long)(last_byte & KASAN_SHADOW_MASK) >= *last_shadow))) + return true; + } + return false; +} + +static __always_inline bool memory_is_poisoned(unsigned long addr, size_t size) +{ + if (__builtin_constant_p(size)) { + switch (size) { + case 1: + return memory_is_poisoned_1(addr); + case 2: + case 4: + case 8: + return memory_is_poisoned_2_4_8(addr, size); + case 16: + return memory_is_poisoned_16(addr); + default: + BUILD_BUG(); + } + } + + return memory_is_poisoned_n(addr, size); +} + +static bool kasan_initialized; + +static __always_inline bool check_memory_region_inline(unsigned long addr, + size_t size, bool write, + unsigned long ret_ip) +{ + if (!kasan_initialized) + return true; + + if (addr < kasan_shadow_start) + return true; + + if (unlikely(size == 0)) + return true; + + if (unlikely(addr + size < addr)) + return !kasan_report(addr, size, write, ret_ip); + + if (addr < kasan_shadow_base) + return true; + + if (likely(!memory_is_poisoned(addr, size))) + return true; + + return !kasan_report(addr, size, write, ret_ip); +} + +void kasan_init(unsigned long membase, unsigned long memsize, + unsigned long shadow_base) +{ + kasan_shadow_start = membase; + kasan_shadow_base = shadow_base; + + kasan_unpoison_shadow((void *)membase, memsize); + kasan_initialized = true; +} + +bool __no_sanitize_address check_memory_region(unsigned long addr, + size_t size, bool write, + unsigned long ret_ip) +{ + return check_memory_region_inline(addr, size, write, ret_ip); +} + +static void register_global(struct kasan_global *global) +{ + size_t aligned_size = round_up(global->size, KASAN_SHADOW_SCALE_SIZE); + + kasan_unpoison_shadow(global->beg, global->size); + + kasan_poison_shadow(global->beg + aligned_size, + global->size_with_redzone - aligned_size, + KASAN_GLOBAL_REDZONE); +} + +void __asan_register_globals(struct kasan_global *globals, size_t size) +{ + int i; + + for (i = 0; i < size; i++) + register_global(&globals[i]); +} +EXPORT_SYMBOL(__asan_register_globals); + +void __asan_unregister_globals(struct kasan_global *globals, size_t size) +{ +} +EXPORT_SYMBOL(__asan_unregister_globals); + +#define DEFINE_ASAN_LOAD_STORE(size) \ + void __no_sanitize_address __asan_load##size(unsigned long addr) \ + { \ + check_memory_region_inline(addr, size, false, _RET_IP_);\ + } \ + EXPORT_SYMBOL(__asan_load##size); \ + __alias(__asan_load##size) \ + void __no_sanitize_address __asan_load##size##_noabort(unsigned long); \ + EXPORT_SYMBOL(__asan_load##size##_noabort); \ + void __asan_store##size(unsigned long addr) \ + { \ + check_memory_region_inline(addr, size, true, _RET_IP_); \ + } \ + EXPORT_SYMBOL(__asan_store##size); \ + __alias(__asan_store##size) \ + void __asan_store##size##_noabort(unsigned long); \ + EXPORT_SYMBOL(__asan_store##size##_noabort) + +DEFINE_ASAN_LOAD_STORE(1); +DEFINE_ASAN_LOAD_STORE(2); +DEFINE_ASAN_LOAD_STORE(4); +DEFINE_ASAN_LOAD_STORE(8); +DEFINE_ASAN_LOAD_STORE(16); + +void __asan_loadN(unsigned long addr, size_t size) +{ + check_memory_region(addr, size, false, _RET_IP_); +} +EXPORT_SYMBOL(__asan_loadN); + +__alias(__asan_loadN) +void __asan_loadN_noabort(unsigned long, size_t); +EXPORT_SYMBOL(__asan_loadN_noabort); + +void __asan_storeN(unsigned long addr, size_t size) +{ + check_memory_region(addr, size, true, _RET_IP_); +} +EXPORT_SYMBOL(__asan_storeN); + +__alias(__asan_storeN) +void __asan_storeN_noabort(unsigned long, size_t); +EXPORT_SYMBOL(__asan_storeN_noabort); + +/* to shut up compiler complaints */ +void __asan_handle_no_return(void) {} +EXPORT_SYMBOL(__asan_handle_no_return); + +/* Emitted by compiler to poison alloca()ed objects. */ +void __asan_alloca_poison(unsigned long addr, size_t size) +{ + size_t rounded_up_size = round_up(size, KASAN_SHADOW_SCALE_SIZE); + size_t padding_size = round_up(size, KASAN_ALLOCA_REDZONE_SIZE) - + rounded_up_size; + size_t rounded_down_size = round_down(size, KASAN_SHADOW_SCALE_SIZE); + + const void *left_redzone = (const void *)(addr - + KASAN_ALLOCA_REDZONE_SIZE); + const void *right_redzone = (const void *)(addr + rounded_up_size); + + WARN_ON(!IS_ALIGNED(addr, KASAN_ALLOCA_REDZONE_SIZE)); + + kasan_unpoison_shadow((const void *)(addr + rounded_down_size), + size - rounded_down_size); + kasan_poison_shadow(left_redzone, KASAN_ALLOCA_REDZONE_SIZE, + KASAN_ALLOCA_LEFT); + kasan_poison_shadow(right_redzone, + padding_size + KASAN_ALLOCA_REDZONE_SIZE, + KASAN_ALLOCA_RIGHT); +} +EXPORT_SYMBOL(__asan_alloca_poison); + +/* Emitted by compiler to unpoison alloca()ed areas when the stack unwinds. */ +void __asan_allocas_unpoison(const void *stack_top, const void *stack_bottom) +{ + if (unlikely(!stack_top || stack_top > stack_bottom)) + return; + + kasan_unpoison_shadow(stack_top, stack_bottom - stack_top); +} +EXPORT_SYMBOL(__asan_allocas_unpoison); + +/* Emitted by the compiler to [un]poison local variables. */ +#define DEFINE_ASAN_SET_SHADOW(byte) \ + void __asan_set_shadow_##byte(const void *addr, size_t size) \ + { \ + __memset((void *)addr, 0x##byte, size); \ + } \ + EXPORT_SYMBOL(__asan_set_shadow_##byte) + +DEFINE_ASAN_SET_SHADOW(00); +DEFINE_ASAN_SET_SHADOW(f1); +DEFINE_ASAN_SET_SHADOW(f2); +DEFINE_ASAN_SET_SHADOW(f3); +DEFINE_ASAN_SET_SHADOW(f5); +DEFINE_ASAN_SET_SHADOW(f8); diff --git a/lib/kasan/generic_report.c b/lib/kasan/generic_report.c new file mode 100644 index 0000000000..1cc5829e8d --- /dev/null +++ b/lib/kasan/generic_report.c @@ -0,0 +1,150 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This file contains generic KASAN specific error reporting code. + * + * Copyright (c) 2014 Samsung Electronics Co., Ltd. + * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com> + * + * Some code borrowed from https://github.com/xairy/kasan-prototype by + * Andrey Konovalov <andreyknvl@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 <common.h> +#include <linux/bitops.h> + +#include <asm/sections.h> + +#include "kasan.h" + +void *find_first_bad_addr(void *addr, size_t size) +{ + void *p = addr; + + while (p < addr + size && !(*(u8 *)kasan_mem_to_shadow(p))) + p += KASAN_SHADOW_SCALE_SIZE; + return p; +} + +static const char *get_shadow_bug_type(struct kasan_access_info *info) +{ + const char *bug_type = "unknown-crash"; + u8 *shadow_addr; + + shadow_addr = (u8 *)kasan_mem_to_shadow(info->first_bad_addr); + + /* + * If shadow byte value is in [0, KASAN_SHADOW_SCALE_SIZE) we can look + * at the next shadow byte to determine the type of the bad access. + */ + if (*shadow_addr > 0 && *shadow_addr <= KASAN_SHADOW_SCALE_SIZE - 1) + shadow_addr++; + + switch (*shadow_addr) { + case 0 ... KASAN_SHADOW_SCALE_SIZE - 1: + /* + * In theory it's still possible to see these shadow values + * due to a data race in the kernel code. + */ + bug_type = "out-of-bounds"; + break; + case KASAN_PAGE_REDZONE: + case KASAN_KMALLOC_REDZONE: + bug_type = "slab-out-of-bounds"; + break; + case KASAN_GLOBAL_REDZONE: + bug_type = "global-out-of-bounds"; + break; + case KASAN_STACK_LEFT: + case KASAN_STACK_MID: + case KASAN_STACK_RIGHT: + case KASAN_STACK_PARTIAL: + bug_type = "stack-out-of-bounds"; + break; + case KASAN_FREE_PAGE: + case KASAN_KMALLOC_FREE: + case KASAN_KMALLOC_FREETRACK: + bug_type = "use-after-free"; + break; + case KASAN_ALLOCA_LEFT: + case KASAN_ALLOCA_RIGHT: + bug_type = "alloca-out-of-bounds"; + break; + case KASAN_VMALLOC_INVALID: + bug_type = "vmalloc-out-of-bounds"; + break; + } + + return bug_type; +} + +static const char *get_wild_bug_type(struct kasan_access_info *info) +{ + const char *bug_type = "unknown-crash"; + + if ((unsigned long)info->access_addr < PAGE_SIZE) + bug_type = "null-ptr-deref"; + else + bug_type = "wild-memory-access"; + + return bug_type; +} + +const char *get_bug_type(struct kasan_access_info *info) +{ + /* + * If access_size is a negative number, then it has reason to be + * defined as out-of-bounds bug type. + * + * Casting negative numbers to size_t would indeed turn up as + * a large size_t and its value will be larger than ULONG_MAX/2, + * so that this can qualify as out-of-bounds. + */ + if (info->access_addr + info->access_size < info->access_addr) + return "out-of-bounds"; + + if (addr_has_shadow(info->access_addr)) + return get_shadow_bug_type(info); + return get_wild_bug_type(info); +} + +#define DEFINE_ASAN_REPORT_LOAD(size) \ +void __asan_report_load##size##_noabort(unsigned long addr) \ +{ \ + kasan_report(addr, size, false, _RET_IP_); \ +} \ +EXPORT_SYMBOL(__asan_report_load##size##_noabort) + +#define DEFINE_ASAN_REPORT_STORE(size) \ +void __asan_report_store##size##_noabort(unsigned long addr) \ +{ \ + kasan_report(addr, size, true, _RET_IP_); \ +} \ +EXPORT_SYMBOL(__asan_report_store##size##_noabort) + +DEFINE_ASAN_REPORT_LOAD(1); +DEFINE_ASAN_REPORT_LOAD(2); +DEFINE_ASAN_REPORT_LOAD(4); +DEFINE_ASAN_REPORT_LOAD(8); +DEFINE_ASAN_REPORT_LOAD(16); +DEFINE_ASAN_REPORT_STORE(1); +DEFINE_ASAN_REPORT_STORE(2); +DEFINE_ASAN_REPORT_STORE(4); +DEFINE_ASAN_REPORT_STORE(8); +DEFINE_ASAN_REPORT_STORE(16); + +void __asan_report_load_n_noabort(unsigned long addr, size_t size) +{ + kasan_report(addr, size, false, _RET_IP_); +} +EXPORT_SYMBOL(__asan_report_load_n_noabort); + +void __asan_report_store_n_noabort(unsigned long addr, size_t size) +{ + kasan_report(addr, size, true, _RET_IP_); +} +EXPORT_SYMBOL(__asan_report_store_n_noabort); diff --git a/lib/kasan/kasan.h b/lib/kasan/kasan.h new file mode 100644 index 0000000000..e17f49dbec --- /dev/null +++ b/lib/kasan/kasan.h @@ -0,0 +1,164 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __MM_KASAN_KASAN_H +#define __MM_KASAN_KASAN_H + +#include <linux/kasan.h> +#include <linux/linkage.h> + +#define KASAN_SHADOW_SCALE_SIZE (1UL << KASAN_SHADOW_SCALE_SHIFT) +#define KASAN_SHADOW_MASK (KASAN_SHADOW_SCALE_SIZE - 1) + +#define KASAN_ALLOCA_REDZONE_SIZE 32 + +/* + * Stack frame marker (compiler ABI). + */ +#define KASAN_CURRENT_STACK_FRAME_MAGIC 0x41B58AB3 + +/* Don't break randconfig/all*config builds */ +#ifndef KASAN_ABI_VERSION +#define KASAN_ABI_VERSION 1 +#endif + +struct kasan_access_info { + const void *access_addr; + const void *first_bad_addr; + size_t access_size; + bool is_write; + unsigned long ip; +}; + +/* The layout of struct dictated by compiler */ +struct kasan_source_location { + const char *filename; + int line_no; + int column_no; +}; + +/* The layout of struct dictated by compiler */ +struct kasan_global { + const void *beg; /* Address of the beginning of the global variable. */ + size_t size; /* Size of the global variable. */ + size_t size_with_redzone; /* Size of the variable + size of the red zone. 32 bytes aligned */ + const void *name; + const void *module_name; /* Name of the module where the global variable is declared. */ + unsigned long has_dynamic_init; /* This needed for C++ */ +#if KASAN_ABI_VERSION >= 4 + struct kasan_source_location *location; +#endif +#if KASAN_ABI_VERSION >= 5 + char *odr_indicator; +#endif +}; + +static inline const void *kasan_shadow_to_mem(const void *shadow_addr) +{ + unsigned long sa = (unsigned long)shadow_addr; + + sa -= kasan_shadow_base; + sa <<= KASAN_SHADOW_SCALE_SHIFT; + sa += kasan_shadow_start; + + return (void *)sa; +} + +static inline bool addr_has_shadow(const void *addr) +{ + return (addr >= (void *)kasan_shadow_start); +} + +/** + * check_memory_region - Check memory region, and report if invalid access. + * @addr: the accessed address + * @size: the accessed size + * @write: true if access is a write access + * @ret_ip: return address + * @return: true if access was valid, false if invalid + */ +bool check_memory_region(unsigned long addr, size_t size, bool write, + unsigned long ret_ip); + +void *find_first_bad_addr(void *addr, size_t size); +const char *get_bug_type(struct kasan_access_info *info); + +bool kasan_report(unsigned long addr, size_t size, + bool is_write, unsigned long ip); +void kasan_report_invalid_free(void *object, unsigned long ip); + +#ifndef arch_kasan_set_tag +static inline const void *arch_kasan_set_tag(const void *addr, u8 tag) +{ + return addr; +} +#endif +#ifndef arch_kasan_reset_tag +#define arch_kasan_reset_tag(addr) ((void *)(addr)) +#endif +#ifndef arch_kasan_get_tag +#define arch_kasan_get_tag(addr) 0 +#endif + +#define set_tag(addr, tag) ((void *)arch_kasan_set_tag((addr), (tag))) +#define reset_tag(addr) ((void *)arch_kasan_reset_tag(addr)) +#define get_tag(addr) arch_kasan_get_tag(addr) + +/* + * Exported functions for interfaces called from assembly or from generated + * code. Declarations here to avoid warning about missing declarations. + */ +asmlinkage void kasan_unpoison_task_stack_below(const void *watermark); +void __asan_register_globals(struct kasan_global *globals, size_t size); +void __asan_unregister_globals(struct kasan_global *globals, size_t size); +void __asan_handle_no_return(void); +void __asan_alloca_poison(unsigned long addr, size_t size); +void __asan_allocas_unpoison(const void *stack_top, const void *stack_bottom); + +void __asan_load1(unsigned long addr); +void __asan_store1(unsigned long addr); +void __asan_load2(unsigned long addr); +void __asan_store2(unsigned long addr); +void __asan_load4(unsigned long addr); +void __asan_store4(unsigned long addr); +void __asan_load8(unsigned long addr); +void __asan_store8(unsigned long addr); +void __asan_load16(unsigned long addr); +void __asan_store16(unsigned long addr); +void __asan_loadN(unsigned long addr, size_t size); +void __asan_storeN(unsigned long addr, size_t size); + +void __asan_load1_noabort(unsigned long addr); +void __asan_store1_noabort(unsigned long addr); +void __asan_load2_noabort(unsigned long addr); +void __asan_store2_noabort(unsigned long addr); +void __asan_load4_noabort(unsigned long addr); +void __asan_store4_noabort(unsigned long addr); +void __asan_load8_noabort(unsigned long addr); +void __asan_store8_noabort(unsigned long addr); +void __asan_load16_noabort(unsigned long addr); +void __asan_store16_noabort(unsigned long addr); +void __asan_loadN_noabort(unsigned long addr, size_t size); +void __asan_storeN_noabort(unsigned long addr, size_t size); + +void __asan_report_load1_noabort(unsigned long addr); +void __asan_report_store1_noabort(unsigned long addr); +void __asan_report_load2_noabort(unsigned long addr); +void __asan_report_store2_noabort(unsigned long addr); +void __asan_report_load4_noabort(unsigned long addr); +void __asan_report_store4_noabort(unsigned long addr); +void __asan_report_load8_noabort(unsigned long addr); +void __asan_report_store8_noabort(unsigned long addr); +void __asan_report_load16_noabort(unsigned long addr); +void __asan_report_store16_noabort(unsigned long addr); +void __asan_report_load_n_noabort(unsigned long addr, size_t size); +void __asan_report_store_n_noabort(unsigned long addr, size_t size); + +void __asan_set_shadow_00(const void *addr, size_t size); +void __asan_set_shadow_f1(const void *addr, size_t size); +void __asan_set_shadow_f2(const void *addr, size_t size); +void __asan_set_shadow_f3(const void *addr, size_t size); +void __asan_set_shadow_f5(const void *addr, size_t size); +void __asan_set_shadow_f8(const void *addr, size_t size); + +extern int kasan_depth; + +#endif diff --git a/lib/kasan/report.c b/lib/kasan/report.c new file mode 100644 index 0000000000..b7b2d032ee --- /dev/null +++ b/lib/kasan/report.c @@ -0,0 +1,199 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This file contains common generic and tag-based KASAN error reporting code. + * + * Copyright (c) 2014 Samsung Electronics Co., Ltd. + * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com> + * + * Some code borrowed from https://github.com/xairy/kasan-prototype by + * Andrey Konovalov <andreyknvl@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 <common.h> +#include <linux/bitops.h> +#include <linux/kernel.h> +#include <printk.h> +#include <asm-generic/sections.h> + +#include "kasan.h" + +/* Shadow layout customization. */ +#define SHADOW_BYTES_PER_BLOCK 1 +#define SHADOW_BLOCKS_PER_ROW 16 +#define SHADOW_BYTES_PER_ROW (SHADOW_BLOCKS_PER_ROW * SHADOW_BYTES_PER_BLOCK) +#define SHADOW_ROWS_AROUND_ADDR 2 + +static unsigned long kasan_flags; + +#define KASAN_BIT_REPORTED 0 +#define KASAN_BIT_MULTI_SHOT 1 + +bool kasan_save_enable_multi_shot(void) +{ + return test_and_set_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags); +} +EXPORT_SYMBOL_GPL(kasan_save_enable_multi_shot); + +void kasan_restore_multi_shot(bool enabled) +{ + if (!enabled) + clear_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags); +} +EXPORT_SYMBOL_GPL(kasan_restore_multi_shot); + +static void print_error_description(struct kasan_access_info *info) +{ + pr_err("BUG: KASAN: %s in %pS\n", + get_bug_type(info), (void *)info->ip); + pr_err("%s of size %zu at addr %px\n", + info->is_write ? "Write" : "Read", info->access_size, + info->access_addr); +} + +static void start_report(unsigned long *flags) +{ + /* + * Make sure we don't end up in loop. + */ + kasan_disable_current(); + pr_err("==================================================================\n"); +} + +static void end_report(unsigned long *flags) +{ + pr_err("==================================================================\n"); + kasan_enable_current(); +} + +static inline bool kernel_or_module_addr(const void *addr) +{ + if (addr >= (void *)_stext && addr < (void *)_end) + return true; + return false; +} + +static void print_address_description(void *addr, u8 tag) +{ + dump_stack(); + pr_err("\n"); + + if (kernel_or_module_addr(addr)) { + pr_err("The buggy address belongs to the variable:\n"); + pr_err(" %pS\n", addr); + } +} + +static bool row_is_guilty(const void *row, const void *guilty) +{ + return (row <= guilty) && (guilty < row + SHADOW_BYTES_PER_ROW); +} + +static int shadow_pointer_offset(const void *row, const void *shadow) +{ + /* The length of ">ff00ff00ff00ff00: " is + * 3 + (BITS_PER_LONG/8)*2 chars. + */ + return 3 + (BITS_PER_LONG/8)*2 + (shadow - row)*2 + + (shadow - row) / SHADOW_BYTES_PER_BLOCK + 1; +} + +static void print_shadow_for_address(const void *addr) +{ + int i; + const void *shadow = kasan_mem_to_shadow(addr); + const void *shadow_row; + + shadow_row = (void *)round_down((unsigned long)shadow, + SHADOW_BYTES_PER_ROW) + - SHADOW_ROWS_AROUND_ADDR * SHADOW_BYTES_PER_ROW; + + pr_err("Memory state around the buggy address:\n"); + + for (i = -SHADOW_ROWS_AROUND_ADDR; i <= SHADOW_ROWS_AROUND_ADDR; i++) { + const void *kaddr = kasan_shadow_to_mem(shadow_row); + char buffer[4 + (BITS_PER_LONG/8)*2]; + char shadow_buf[SHADOW_BYTES_PER_ROW]; + + snprintf(buffer, sizeof(buffer), + (i == 0) ? ">%px: " : " %px: ", kaddr); + /* + * We should not pass a shadow pointer to generic + * function, because generic functions may try to + * access kasan mapping for the passed address. + */ + memcpy(shadow_buf, shadow_row, SHADOW_BYTES_PER_ROW); + print_hex_dump(KERN_ERR, buffer, + DUMP_PREFIX_NONE, SHADOW_BYTES_PER_ROW, 1, + shadow_buf, SHADOW_BYTES_PER_ROW, 0); + + if (row_is_guilty(shadow_row, shadow)) + printf("%*c\n", + shadow_pointer_offset(shadow_row, shadow), + '^'); + + shadow_row += SHADOW_BYTES_PER_ROW; + } +} + +static bool report_enabled(void) +{ + if (kasan_depth) + return false; + if (test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags)) + return true; + return !test_and_set_bit(KASAN_BIT_REPORTED, &kasan_flags); +} + +static void __kasan_report(unsigned long addr, size_t size, bool is_write, + unsigned long ip) +{ + struct kasan_access_info info; + void *tagged_addr; + void *untagged_addr; + unsigned long flags; + + tagged_addr = (void *)addr; + untagged_addr = reset_tag(tagged_addr); + + info.access_addr = tagged_addr; + if (addr_has_shadow(untagged_addr)) + info.first_bad_addr = find_first_bad_addr(tagged_addr, size); + else + info.first_bad_addr = untagged_addr; + info.access_size = size; + info.is_write = is_write; + info.ip = ip; + + start_report(&flags); + + print_error_description(&info); + pr_err("\n"); + + if (addr_has_shadow(untagged_addr)) { + print_address_description(untagged_addr, get_tag(tagged_addr)); + pr_err("\n"); + print_shadow_for_address(info.first_bad_addr); + } else { + dump_stack(); + } + + end_report(&flags); +} + +bool kasan_report(unsigned long addr, size_t size, bool is_write, + unsigned long ip) +{ + bool ret = false; + + if (likely(report_enabled())) { + __kasan_report(addr, size, is_write, ip); + ret = true; + } + + return ret; +} diff --git a/lib/string.c b/lib/string.c index 18ef13dfd8..c0bf372657 100644 --- a/lib/string.c +++ b/lib/string.c @@ -515,6 +515,7 @@ EXPORT_SYMBOL(__nokasan_default_memset); #ifndef __HAVE_ARCH_MEMSET void *memset(void *s, int c, size_t count) __alias(__default_memset); +void *__memset(void *s, int c, size_t count) __alias(__default_memset); #endif /** @@ -552,6 +553,8 @@ EXPORT_SYMBOL(__nokasan_default_memcpy); #ifndef __HAVE_ARCH_MEMCPY void *memcpy(void * dest, const void *src, size_t count) __alias(__default_memcpy); +void *__memcpy(void * dest, const void *src, size_t count) + __alias(__default_memcpy); #endif diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan new file mode 100644 index 0000000000..83f6aa543d --- /dev/null +++ b/scripts/Makefile.kasan @@ -0,0 +1,17 @@ + # SPDX-License-Identifier: GPL-2.0 +ifdef CONFIG_KASAN +CFLAGS_KASAN_NOSANITIZE := -fno-builtin +KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET) +endif + +CFLAGS_KASAN_MINIMAL := -fsanitize=kernel-address + +cc-param = $(call cc-option, -mllvm -$(1), $(call cc-option, --param $(1))) + +CFLAGS_KASAN := $(CFLAGS_KASAN_MINIMAL) \ + $(call cc-param,asan-globals=1) \ + $(call cc-param,asan-instrument-allocas=1) + +ifndef CONFIG_CPU_64 +CFLAGS_KASAN += $(call cc-param,asan-stack=1) +endif diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 337430cd00..ab7d9f2bdf 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -127,6 +127,16 @@ _c_flags = $(KBUILD_CFLAGS) $(ccflags-y) $(CFLAGS_$(target-stem).o) _a_flags = $(KBUILD_AFLAGS) $(asflags-y) $(AFLAGS_$(target-stem).o) _cpp_flags = $(KBUILD_CPPFLAGS) $(cppflags-y) $(CPPFLAGS_$(target-stem).lds) +# +# Enable address sanitizer flags for kernel except some files or directories +# we don't want to check (depends on variables KASAN_SANITIZE_obj.o, KASAN_SANITIZE) +# +ifeq ($(CONFIG_KASAN),y) +_c_flags += $(if $(part-of-pbl),, $(if $(patsubst n%,, \ + $(KASAN_SANITIZE_$(basetarget).o)$(KASAN_SANITIZE)y), \ + $(CFLAGS_KASAN), $(CFLAGS_KASAN_NOSANITIZE))) +endif + ifeq ($(CONFIG_UBSAN),y) _CFLAGS_UBSAN = $(eval _CFLAGS_UBSAN := $(CFLAGS_UBSAN))$(_CFLAGS_UBSAN) _c_flags += $(if $(patsubst n%,, \ |