Re: [PATCH v9 38/44] kasan, arm64: expand CONFIG_KASAN checks

From: Alexander Potapenko
Date: Wed Nov 11 2020 - 11:22:59 EST

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In reply to: Andrey Konovalov: "[PATCH v9 38/44] kasan, arm64: expand CONFIG_KASAN checks"
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On Tue, Nov 10, 2020 at 11:12 PM Andrey Konovalov <andreyknvl@xxxxxxxxxx> wrote:
>
> Some #ifdef CONFIG_KASAN checks are only relevant for software KASAN
> modes (either related to shadow memory or compiler instrumentation).
> Expand those into CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS.
>
> Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
> Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Reviewed-by: Alexander Potapenko <glider@xxxxxxxxxx>

> ---
> Change-Id: I91e661e2c1627783cb845d877c6371dfc8779505
> ---
> arch/arm64/Kconfig | 2 +-
> arch/arm64/Makefile | 2 +-
> arch/arm64/include/asm/assembler.h | 2 +-
> arch/arm64/include/asm/memory.h | 2 +-
> arch/arm64/include/asm/string.h | 5 +++--
> arch/arm64/kernel/head.S | 2 +-
> arch/arm64/kernel/image-vars.h | 2 +-
> arch/arm64/kernel/kaslr.c | 3 ++-
> arch/arm64/kernel/module.c | 6 ++++--
> arch/arm64/mm/ptdump.c | 6 +++---
> include/linux/kasan-checks.h | 2 +-
> include/linux/kasan.h | 7 ++++---
> include/linux/moduleloader.h | 3 ++-
> include/linux/string.h | 2 +-
> mm/ptdump.c | 13 ++++++++-----
> scripts/Makefile.lib | 2 ++
> 16 files changed, 36 insertions(+), 25 deletions(-)
>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index c84a0e6b4650..456741645f01 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -330,7 +330,7 @@ config BROKEN_GAS_INST
>
> config KASAN_SHADOW_OFFSET
> hex
> - depends on KASAN
> + depends on KASAN_GENERIC || KASAN_SW_TAGS
> default 0xdfffa00000000000 if (ARM64_VA_BITS_48 || ARM64_VA_BITS_52) && !KASAN_SW_TAGS
> default 0xdfffd00000000000 if ARM64_VA_BITS_47 && !KASAN_SW_TAGS
> default 0xdffffe8000000000 if ARM64_VA_BITS_42 && !KASAN_SW_TAGS
> diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
> index 50ad9cbccb51..0b31a3f06f15 100644
> --- a/arch/arm64/Makefile
> +++ b/arch/arm64/Makefile
> @@ -141,7 +141,7 @@ head-y := arch/arm64/kernel/head.o
>
> ifeq ($(CONFIG_KASAN_SW_TAGS), y)
> KASAN_SHADOW_SCALE_SHIFT := 4
> -else
> +else ifeq ($(CONFIG_KASAN_GENERIC), y)
> KASAN_SHADOW_SCALE_SHIFT := 3
> endif
>
> diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
> index ddbe6bf00e33..bf125c591116 100644
> --- a/arch/arm64/include/asm/assembler.h
> +++ b/arch/arm64/include/asm/assembler.h
> @@ -473,7 +473,7 @@ USER(\label, ic ivau, \tmp2) // invalidate I line PoU
> #define NOKPROBE(x)
> #endif
>
> -#ifdef CONFIG_KASAN
> +#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
> #define EXPORT_SYMBOL_NOKASAN(name)
> #else
> #define EXPORT_SYMBOL_NOKASAN(name) EXPORT_SYMBOL(name)
> diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
> index 419bbace29d5..656aaddb7014 100644
> --- a/arch/arm64/include/asm/memory.h
> +++ b/arch/arm64/include/asm/memory.h
> @@ -72,7 +72,7 @@
> * address space for the shadow region respectively. They can bloat the stack
> * significantly, so double the (minimum) stack size when they are in use.
> */
> -#ifdef CONFIG_KASAN
> +#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
> #define KASAN_SHADOW_OFFSET _AC(CONFIG_KASAN_SHADOW_OFFSET, UL)
> #define KASAN_SHADOW_END ((UL(1) << (64 - KASAN_SHADOW_SCALE_SHIFT)) \
> + KASAN_SHADOW_OFFSET)
> diff --git a/arch/arm64/include/asm/string.h b/arch/arm64/include/asm/string.h
> index b31e8e87a0db..3a3264ff47b9 100644
> --- a/arch/arm64/include/asm/string.h
> +++ b/arch/arm64/include/asm/string.h
> @@ -5,7 +5,7 @@
> #ifndef __ASM_STRING_H
> #define __ASM_STRING_H
>
> -#ifndef CONFIG_KASAN
> +#if !(defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS))
> #define __HAVE_ARCH_STRRCHR
> extern char *strrchr(const char *, int c);
>
> @@ -48,7 +48,8 @@ extern void *__memset(void *, int, __kernel_size_t);
> void memcpy_flushcache(void *dst, const void *src, size_t cnt);
> #endif
>
> -#if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__)
> +#if (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) && \
> + !defined(__SANITIZE_ADDRESS__)
>
> /*
> * For files that are not instrumented (e.g. mm/slub.c) we
> diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
> index d8d9caf02834..fdcb99d7ba23 100644
> --- a/arch/arm64/kernel/head.S
> +++ b/arch/arm64/kernel/head.S
> @@ -448,7 +448,7 @@ SYM_FUNC_START_LOCAL(__primary_switched)
> bl __pi_memset
> dsb ishst // Make zero page visible to PTW
>
> -#ifdef CONFIG_KASAN
> +#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
> bl kasan_early_init
> #endif
> #ifdef CONFIG_RANDOMIZE_BASE
> diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
> index c615b285ff5b..4282edd2fe81 100644
> --- a/arch/arm64/kernel/image-vars.h
> +++ b/arch/arm64/kernel/image-vars.h
> @@ -37,7 +37,7 @@ __efistub_strncmp = __pi_strncmp;
> __efistub_strrchr = __pi_strrchr;
> __efistub___clean_dcache_area_poc = __pi___clean_dcache_area_poc;
>
> -#ifdef CONFIG_KASAN
> +#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
> __efistub___memcpy = __pi_memcpy;
> __efistub___memmove = __pi_memmove;
> __efistub___memset = __pi_memset;
> diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c
> index b181e0544b79..e8e17e91aa02 100644
> --- a/arch/arm64/kernel/kaslr.c
> +++ b/arch/arm64/kernel/kaslr.c
> @@ -151,7 +151,8 @@ u64 __init kaslr_early_init(u64 dt_phys)
> /* use the top 16 bits to randomize the linear region */
> memstart_offset_seed = seed >> 48;
>
> - if (IS_ENABLED(CONFIG_KASAN))
> + if (IS_ENABLED(CONFIG_KASAN_GENERIC) ||
> + IS_ENABLED(CONFIG_KASAN_SW_TAGS))
> /*
> * KASAN does not expect the module region to intersect the
> * vmalloc region, since shadow memory is allocated for each
> diff --git a/arch/arm64/kernel/module.c b/arch/arm64/kernel/module.c
> index 2a1ad95d9b2c..fe21e0f06492 100644
> --- a/arch/arm64/kernel/module.c
> +++ b/arch/arm64/kernel/module.c
> @@ -30,7 +30,8 @@ void *module_alloc(unsigned long size)
> if (IS_ENABLED(CONFIG_ARM64_MODULE_PLTS))
> gfp_mask |= __GFP_NOWARN;
>
> - if (IS_ENABLED(CONFIG_KASAN))
> + if (IS_ENABLED(CONFIG_KASAN_GENERIC) ||
> + IS_ENABLED(CONFIG_KASAN_SW_TAGS))
> /* don't exceed the static module region - see below */
> module_alloc_end = MODULES_END;
>
> @@ -39,7 +40,8 @@ void *module_alloc(unsigned long size)
> NUMA_NO_NODE, __builtin_return_address(0));
>
> if (!p && IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) &&
> - !IS_ENABLED(CONFIG_KASAN))
> + !IS_ENABLED(CONFIG_KASAN_GENERIC) &&
> + !IS_ENABLED(CONFIG_KASAN_SW_TAGS))
> /*
> * KASAN can only deal with module allocations being served
> * from the reserved module region, since the remainder of
> diff --git a/arch/arm64/mm/ptdump.c b/arch/arm64/mm/ptdump.c
> index 807dc634bbd2..04137a8f3d2d 100644
> --- a/arch/arm64/mm/ptdump.c
> +++ b/arch/arm64/mm/ptdump.c
> @@ -29,7 +29,7 @@
> enum address_markers_idx {
> PAGE_OFFSET_NR = 0,
> PAGE_END_NR,
> -#ifdef CONFIG_KASAN
> +#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
> KASAN_START_NR,
> #endif
> };
> @@ -37,7 +37,7 @@ enum address_markers_idx {
> static struct addr_marker address_markers[] = {
> { PAGE_OFFSET, "Linear Mapping start" },
> { 0 /* PAGE_END */, "Linear Mapping end" },
> -#ifdef CONFIG_KASAN
> +#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
> { 0 /* KASAN_SHADOW_START */, "Kasan shadow start" },
> { KASAN_SHADOW_END, "Kasan shadow end" },
> #endif
> @@ -383,7 +383,7 @@ void ptdump_check_wx(void)
> static int ptdump_init(void)
> {
> address_markers[PAGE_END_NR].start_address = PAGE_END;
> -#ifdef CONFIG_KASAN
> +#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
> address_markers[KASAN_START_NR].start_address = KASAN_SHADOW_START;
> #endif
> ptdump_initialize();
> diff --git a/include/linux/kasan-checks.h b/include/linux/kasan-checks.h
> index ac6aba632f2d..ca5e89fb10d3 100644
> --- a/include/linux/kasan-checks.h
> +++ b/include/linux/kasan-checks.h
> @@ -9,7 +9,7 @@
> * even in compilation units that selectively disable KASAN, but must use KASAN
> * to validate access to an address. Never use these in header files!
> */
> -#ifdef CONFIG_KASAN
> +#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
> bool __kasan_check_read(const volatile void *p, unsigned int size);
> bool __kasan_check_write(const volatile void *p, unsigned int size);
> #else
> diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> index 1d6ec3325163..b6fc14b3da53 100644
> --- a/include/linux/kasan.h
> +++ b/include/linux/kasan.h
> @@ -237,7 +237,8 @@ static inline void kasan_release_vmalloc(unsigned long start,
>
> #endif /* CONFIG_KASAN_VMALLOC */
>
> -#if defined(CONFIG_KASAN) && !defined(CONFIG_KASAN_VMALLOC)
> +#if (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) && \
> + !defined(CONFIG_KASAN_VMALLOC)
>
> /*
> * These functions provide a special case to support backing module
> @@ -247,12 +248,12 @@ static inline void kasan_release_vmalloc(unsigned long start,
> int kasan_module_alloc(void *addr, size_t size);
> void kasan_free_shadow(const struct vm_struct *vm);
>
> -#else /* CONFIG_KASAN && !CONFIG_KASAN_VMALLOC */
> +#else /* (CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS) && !CONFIG_KASAN_VMALLOC */
>
> static inline int kasan_module_alloc(void *addr, size_t size) { return 0; }
> static inline void kasan_free_shadow(const struct vm_struct *vm) {}
>
> -#endif /* CONFIG_KASAN && !CONFIG_KASAN_VMALLOC */
> +#endif /* (CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS) && !CONFIG_KASAN_VMALLOC */
>
> #ifdef CONFIG_KASAN_INLINE
> void kasan_non_canonical_hook(unsigned long addr);
> diff --git a/include/linux/moduleloader.h b/include/linux/moduleloader.h
> index 4fa67a8b2265..9e09d11ffe5b 100644
> --- a/include/linux/moduleloader.h
> +++ b/include/linux/moduleloader.h
> @@ -96,7 +96,8 @@ void module_arch_cleanup(struct module *mod);
> /* Any cleanup before freeing mod->module_init */
> void module_arch_freeing_init(struct module *mod);
>
> -#if defined(CONFIG_KASAN) && !defined(CONFIG_KASAN_VMALLOC)
> +#if (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) && \
> + !defined(CONFIG_KASAN_VMALLOC)
> #include <linux/kasan.h>
> #define MODULE_ALIGN (PAGE_SIZE << KASAN_SHADOW_SCALE_SHIFT)
> #else
> diff --git a/include/linux/string.h b/include/linux/string.h
> index b1f3894a0a3e..016a157e2251 100644
> --- a/include/linux/string.h
> +++ b/include/linux/string.h
> @@ -266,7 +266,7 @@ void __write_overflow(void) __compiletime_error("detected write beyond size of o
>
> #if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE)
>
> -#ifdef CONFIG_KASAN
> +#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
> extern void *__underlying_memchr(const void *p, int c, __kernel_size_t size) __RENAME(memchr);
> extern int __underlying_memcmp(const void *p, const void *q, __kernel_size_t size) __RENAME(memcmp);
> extern void *__underlying_memcpy(void *p, const void *q, __kernel_size_t size) __RENAME(memcpy);
> diff --git a/mm/ptdump.c b/mm/ptdump.c
> index ba88ec43ff21..4354c1422d57 100644
> --- a/mm/ptdump.c
> +++ b/mm/ptdump.c
> @@ -4,7 +4,7 @@
> #include <linux/ptdump.h>
> #include <linux/kasan.h>
>
> -#ifdef CONFIG_KASAN
> +#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
> /*
> * This is an optimization for KASAN=y case. Since all kasan page tables
> * eventually point to the kasan_early_shadow_page we could call note_page()
> @@ -31,7 +31,8 @@ static int ptdump_pgd_entry(pgd_t *pgd, unsigned long addr,
> struct ptdump_state *st = walk->private;
> pgd_t val = READ_ONCE(*pgd);
>
> -#if CONFIG_PGTABLE_LEVELS > 4 && defined(CONFIG_KASAN)
> +#if CONFIG_PGTABLE_LEVELS > 4 && \
> + (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS))
> if (pgd_page(val) == virt_to_page(lm_alias(kasan_early_shadow_p4d)))
> return note_kasan_page_table(walk, addr);
> #endif
> @@ -51,7 +52,8 @@ static int ptdump_p4d_entry(p4d_t *p4d, unsigned long addr,
> struct ptdump_state *st = walk->private;
> p4d_t val = READ_ONCE(*p4d);
>
> -#if CONFIG_PGTABLE_LEVELS > 3 && defined(CONFIG_KASAN)
> +#if CONFIG_PGTABLE_LEVELS > 3 && \
> + (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS))
> if (p4d_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pud)))
> return note_kasan_page_table(walk, addr);
> #endif
> @@ -71,7 +73,8 @@ static int ptdump_pud_entry(pud_t *pud, unsigned long addr,
> struct ptdump_state *st = walk->private;
> pud_t val = READ_ONCE(*pud);
>
> -#if CONFIG_PGTABLE_LEVELS > 2 && defined(CONFIG_KASAN)
> +#if CONFIG_PGTABLE_LEVELS > 2 && \
> + (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS))
> if (pud_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pmd)))
> return note_kasan_page_table(walk, addr);
> #endif
> @@ -91,7 +94,7 @@ static int ptdump_pmd_entry(pmd_t *pmd, unsigned long addr,
> struct ptdump_state *st = walk->private;
> pmd_t val = READ_ONCE(*pmd);
>
> -#if defined(CONFIG_KASAN)
> +#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
> if (pmd_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pte)))
> return note_kasan_page_table(walk, addr);
> #endif
> diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
> index 94133708889d..213677a5ed33 100644
> --- a/scripts/Makefile.lib
> +++ b/scripts/Makefile.lib
> @@ -148,10 +148,12 @@ endif
> # we don't want to check (depends on variables KASAN_SANITIZE_obj.o, KASAN_SANITIZE)
> #
> ifeq ($(CONFIG_KASAN),y)
> +ifneq ($(CONFIG_KASAN_HW_TAGS),y)
> _c_flags += $(if $(patsubst n%,, \
> $(KASAN_SANITIZE_$(basetarget).o)$(KASAN_SANITIZE)y), \
> $(CFLAGS_KASAN), $(CFLAGS_KASAN_NOSANITIZE))
> endif
> +endif
>
> ifeq ($(CONFIG_UBSAN),y)
> _c_flags += $(if $(patsubst n%,, \
> --
> 2.29.2.222.g5d2a92d10f8-goog
>

--
Alexander Potapenko
Software Engineer

Google Germany GmbH
Erika-Mann-Straße, 33
80636 München

Geschäftsführer: Paul Manicle, Halimah DeLaine Prado
Registergericht und -nummer: Hamburg, HRB 86891
Sitz der Gesellschaft: Hamburg

Next message: Sven Van Asbroeck: "Re: [PATCH v1] spi: fix client driver breakages when using GPIO descriptors"
Previous message: Jakub Kicinski: "Re: [PATCH net-next] net: stmmac: platform: use optional clk/reset get APIs"
In reply to: Andrey Konovalov: "[PATCH v9 38/44] kasan, arm64: expand CONFIG_KASAN checks"
Next in thread: Andrey Konovalov: "[PATCH v9 41/44] kasan, mm: reset tags when accessing metadata"
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