From: elver@google.com
To: Andrey Konovalov <andreyknvl@google.com>
Cc: linux-arm-kernel@lists.infradead.org,
Branislav Rankov <Branislav.Rankov@arm.com>,
Elena Petrova <lenaptr@google.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Kevin Brodsky <kevin.brodsky@arm.com>,
Will Deacon <will.deacon@arm.com>,
linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
linux-mm@kvack.org, Alexander Potapenko <glider@google.com>,
Evgenii Stepanov <eugenis@google.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Andrew Morton <akpm@linux-foundation.org>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Dmitry Vyukov <dvyukov@google.com>
Subject: Re: [PATCH v3 20/39] kasan: separate metadata_fetch_row for each mode
Date: Thu, 1 Oct 2020 19:54:02 +0200 [thread overview]
Message-ID: <20201001175402.GP4162920@elver.google.com> (raw)
In-Reply-To: <494045645c31b7f9298851118cb0b7f8964ac0f4.1600987622.git.andreyknvl@google.com>
On Fri, Sep 25, 2020 at 12:50AM +0200, Andrey Konovalov wrote:
> This is a preparatory commit for the upcoming addition of a new hardware
> tag-based (MTE-based) KASAN mode.
Not sure why I've only noticed this now, but all these patches seem to
say "This is a preparatory commit" -- I don't think "commit" is
applicable, and "This .. patch" is discouraged.
Maybe just change it to say "This is to prepare for the upcoming ..."
after the below paragraph?
> Rework print_memory_metadata() to make it agnostic with regard to the
> way metadata is stored. Allow providing a separate metadata_fetch_row()
> implementation for each KASAN mode. Hardware tag-based KASAN will provide
> its own implementation that doesn't use shadow memory.
(i.e. move it here)
> No functional changes for software modes.
>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Other than that,
Reviewed-by: Marco Elver <elver@google.com>
> ---
> Change-Id: I5b0ed1d079ea776e620beca6a529a861e7dced95
> ---
> mm/kasan/kasan.h | 8 ++++++
> mm/kasan/report.c | 56 +++++++++++++++++++--------------------
> mm/kasan/report_generic.c | 5 ++++
> mm/kasan/report_sw_tags.c | 5 ++++
> 4 files changed, 45 insertions(+), 29 deletions(-)
>
> diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> index 0bf669fad345..50b59c8f8be2 100644
> --- a/mm/kasan/kasan.h
> +++ b/mm/kasan/kasan.h
> @@ -57,6 +57,13 @@
> #define KASAN_ABI_VERSION 1
> #endif
>
> +/* Metadata layout customization. */
> +#define META_BYTES_PER_BLOCK 1
> +#define META_BLOCKS_PER_ROW 16
> +#define META_BYTES_PER_ROW (META_BLOCKS_PER_ROW * META_BYTES_PER_BLOCK)
> +#define META_MEM_BYTES_PER_ROW (META_BYTES_PER_ROW * KASAN_GRANULE_SIZE)
> +#define META_ROWS_AROUND_ADDR 2
> +
> struct kasan_access_info {
> const void *access_addr;
> const void *first_bad_addr;
> @@ -168,6 +175,7 @@ bool check_invalid_free(void *addr);
>
> void *find_first_bad_addr(void *addr, size_t size);
> const char *get_bug_type(struct kasan_access_info *info);
> +void metadata_fetch_row(char *buffer, void *row);
>
> #ifdef CONFIG_KASAN_STACK_ENABLE
> void print_address_stack_frame(const void *addr);
> diff --git a/mm/kasan/report.c b/mm/kasan/report.c
> index 13b27675a696..3924127b4786 100644
> --- a/mm/kasan/report.c
> +++ b/mm/kasan/report.c
> @@ -31,12 +31,6 @@
> #include "kasan.h"
> #include "../slab.h"
>
> -/* Metadata layout customization. */
> -#define META_BYTES_PER_BLOCK 1
> -#define META_BLOCKS_PER_ROW 16
> -#define META_BYTES_PER_ROW (META_BLOCKS_PER_ROW * META_BYTES_PER_BLOCK)
> -#define META_ROWS_AROUND_ADDR 2
> -
> static unsigned long kasan_flags;
>
> #define KASAN_BIT_REPORTED 0
> @@ -236,55 +230,59 @@ static void print_address_description(void *addr, u8 tag)
> print_address_stack_frame(addr);
> }
>
> -static bool row_is_guilty(const void *row, const void *guilty)
> +static bool meta_row_is_guilty(const void *row, const void *addr)
> {
> - return (row <= guilty) && (guilty < row + META_BYTES_PER_ROW);
> + return (row <= addr) && (addr < row + META_MEM_BYTES_PER_ROW);
> }
>
> -static int shadow_pointer_offset(const void *row, const void *shadow)
> +static int meta_pointer_offset(const void *row, const void *addr)
> {
> - /* The length of ">ff00ff00ff00ff00: " is
> - * 3 + (BITS_PER_LONG/8)*2 chars.
> + /*
> + * Memory state around the buggy address:
> + * ff00ff00ff00ff00: 00 00 00 05 fe fe fe fe fe fe fe fe fe fe fe fe
> + * ...
> + *
> + * The length of ">ff00ff00ff00ff00: " is
> + * 3 + (BITS_PER_LONG / 8) * 2 chars.
> + * The length of each granule metadata is 2 bytes
> + * plus 1 byte for space.
> */
> - return 3 + (BITS_PER_LONG/8)*2 + (shadow - row)*2 +
> - (shadow - row) / META_BYTES_PER_BLOCK + 1;
> + return 3 + (BITS_PER_LONG / 8) * 2 +
> + (addr - row) / KASAN_GRANULE_SIZE * 3 + 1;
> }
>
> static void print_memory_metadata(const void *addr)
> {
> int i;
> - const void *shadow = kasan_mem_to_shadow(addr);
> - const void *shadow_row;
> + void *row;
>
> - shadow_row = (void *)round_down((unsigned long)shadow,
> - META_BYTES_PER_ROW)
> - - META_ROWS_AROUND_ADDR * META_BYTES_PER_ROW;
> + row = (void *)round_down((unsigned long)addr, META_MEM_BYTES_PER_ROW)
> + - META_ROWS_AROUND_ADDR * META_MEM_BYTES_PER_ROW;
>
> pr_err("Memory state around the buggy address:\n");
>
> for (i = -META_ROWS_AROUND_ADDR; i <= META_ROWS_AROUND_ADDR; i++) {
> - const void *kaddr = kasan_shadow_to_mem(shadow_row);
> - char buffer[4 + (BITS_PER_LONG/8)*2];
> - char shadow_buf[META_BYTES_PER_ROW];
> + char buffer[4 + (BITS_PER_LONG / 8) * 2];
> + char metadata[META_BYTES_PER_ROW];
>
> snprintf(buffer, sizeof(buffer),
> - (i == 0) ? ">%px: " : " %px: ", kaddr);
> + (i == 0) ? ">%px: " : " %px: ", row);
> +
> /*
> * 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, META_BYTES_PER_ROW);
> + metadata_fetch_row(&metadata[0], row);
> +
> print_hex_dump(KERN_ERR, buffer,
> DUMP_PREFIX_NONE, META_BYTES_PER_ROW, 1,
> - shadow_buf, META_BYTES_PER_ROW, 0);
> + metadata, META_BYTES_PER_ROW, 0);
>
> - if (row_is_guilty(shadow_row, shadow))
> - pr_err("%*c\n",
> - shadow_pointer_offset(shadow_row, shadow),
> - '^');
> + if (meta_row_is_guilty(row, addr))
> + pr_err("%*c\n", meta_pointer_offset(row, addr), '^');
>
> - shadow_row += META_BYTES_PER_ROW;
> + row += META_MEM_BYTES_PER_ROW;
> }
> }
>
> diff --git a/mm/kasan/report_generic.c b/mm/kasan/report_generic.c
> index ff067071cd28..de7a85c83106 100644
> --- a/mm/kasan/report_generic.c
> +++ b/mm/kasan/report_generic.c
> @@ -122,6 +122,11 @@ const char *get_bug_type(struct kasan_access_info *info)
> return get_wild_bug_type(info);
> }
>
> +void metadata_fetch_row(char *buffer, void *row)
> +{
> + memcpy(buffer, kasan_mem_to_shadow(row), META_BYTES_PER_ROW);
> +}
> +
> #ifdef CONFIG_KASAN_STACK_ENABLE
> static bool __must_check tokenize_frame_descr(const char **frame_descr,
> char *token, size_t max_tok_len,
> diff --git a/mm/kasan/report_sw_tags.c b/mm/kasan/report_sw_tags.c
> index c87d5a343b4e..add2dfe6169c 100644
> --- a/mm/kasan/report_sw_tags.c
> +++ b/mm/kasan/report_sw_tags.c
> @@ -80,6 +80,11 @@ void *find_first_bad_addr(void *addr, size_t size)
> return p;
> }
>
> +void metadata_fetch_row(char *buffer, void *row)
> +{
> + memcpy(buffer, kasan_mem_to_shadow(row), META_BYTES_PER_ROW);
> +}
> +
> void print_tags(u8 addr_tag, const void *addr)
> {
> u8 *shadow = (u8 *)kasan_mem_to_shadow(addr);
> --
> 2.28.0.681.g6f77f65b4e-goog
>
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next prev parent reply other threads:[~2020-10-01 17:55 UTC|newest]
Thread overview: 88+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-24 22:50 [PATCH v3 00/39] kasan: add hardware tag-based mode for arm64 Andrey Konovalov
2020-09-24 22:50 ` [PATCH v3 01/39] kasan: drop unnecessary GPL text from comment headers Andrey Konovalov
2020-10-01 17:18 ` elver
2020-09-24 22:50 ` [PATCH v3 02/39] kasan: KASAN_VMALLOC depends on KASAN_GENERIC Andrey Konovalov
2020-10-01 17:19 ` elver
2020-09-24 22:50 ` [PATCH v3 03/39] kasan: group vmalloc code Andrey Konovalov
2020-10-01 17:27 ` elver
2020-09-24 22:50 ` [PATCH v3 04/39] kasan: shadow declarations only for software modes Andrey Konovalov
2020-10-01 17:29 ` elver
2020-09-24 22:50 ` [PATCH v3 05/39] kasan: rename (un)poison_shadow to (un)poison_memory Andrey Konovalov
2020-10-01 17:29 ` elver
2020-09-24 22:50 ` [PATCH v3 06/39] kasan: rename KASAN_SHADOW_* to KASAN_GRANULE_* Andrey Konovalov
2020-10-01 17:30 ` elver
2020-09-24 22:50 ` [PATCH v3 07/39] kasan: only build init.c for software modes Andrey Konovalov
2020-10-01 17:31 ` elver
2020-09-24 22:50 ` [PATCH v3 08/39] kasan: split out shadow.c from common.c Andrey Konovalov
2020-10-01 17:32 ` elver
2020-09-24 22:50 ` [PATCH v3 09/39] kasan: define KASAN_GRANULE_PAGE Andrey Konovalov
2020-10-01 17:33 ` elver
2020-09-24 22:50 ` [PATCH v3 10/39] kasan: rename report and tags files Andrey Konovalov
2020-10-01 17:36 ` elver
2020-09-24 22:50 ` [PATCH v3 11/39] kasan: don't duplicate config dependencies Andrey Konovalov
2020-10-01 17:39 ` elver
2020-10-01 21:54 ` Andrey Konovalov
2020-09-24 22:50 ` [PATCH v3 12/39] kasan: hide invalid free check implementation Andrey Konovalov
2020-10-01 17:41 ` elver
2020-09-24 22:50 ` [PATCH v3 13/39] kasan: decode stack frame only with KASAN_STACK_ENABLE Andrey Konovalov
2020-10-01 17:43 ` elver
2020-09-24 22:50 ` [PATCH v3 14/39] kasan, arm64: only init shadow for software modes Andrey Konovalov
2020-09-24 22:50 ` [PATCH v3 15/39] kasan, arm64: only use kasan_depth " Andrey Konovalov
2020-09-24 22:50 ` [PATCH v3 16/39] kasan: rename addr_has_shadow to addr_has_metadata Andrey Konovalov
2020-10-01 17:45 ` elver
2020-09-24 22:50 ` [PATCH v3 17/39] kasan: rename print_shadow_for_address to print_memory_metadata Andrey Konovalov
2020-10-01 17:45 ` elver
2020-09-24 22:50 ` [PATCH v3 18/39] kasan: kasan_non_canonical_hook only for software modes Andrey Konovalov
2020-10-01 17:47 ` elver
2020-09-24 22:50 ` [PATCH v3 19/39] kasan: rename SHADOW layout macros to META Andrey Konovalov
2020-10-01 17:48 ` elver
2020-09-24 22:50 ` [PATCH v3 20/39] kasan: separate metadata_fetch_row for each mode Andrey Konovalov
2020-10-01 17:54 ` elver [this message]
2020-10-01 21:56 ` Andrey Konovalov
2020-09-24 22:50 ` [PATCH v3 21/39] kasan: don't allow SW_TAGS with ARM64_MTE Andrey Konovalov
2020-10-01 17:55 ` elver
2020-10-01 21:57 ` Andrey Konovalov
2020-09-24 22:50 ` [PATCH v3 22/39] kasan: introduce CONFIG_KASAN_HW_TAGS Andrey Konovalov
2020-10-01 17:57 ` elver
2020-09-24 22:50 ` [PATCH v3 23/39] arm64: Enable armv8.5-a asm-arch option Andrey Konovalov
2020-09-25 10:16 ` Catalin Marinas
2020-09-24 22:50 ` [PATCH v3 24/39] arm64: mte: Add in-kernel MTE helpers Andrey Konovalov
2020-09-25 10:15 ` Catalin Marinas
2020-09-25 11:28 ` Vincenzo Frascino
2020-09-25 12:50 ` Catalin Marinas
2020-09-25 13:36 ` Vincenzo Frascino
2020-09-24 22:50 ` [PATCH v3 25/39] arm64: kasan: Add arch layer for memory tagging helpers Andrey Konovalov
2020-09-24 22:50 ` [PATCH v3 26/39] arm64: mte: Add in-kernel tag fault handler Andrey Konovalov
2020-09-25 10:49 ` Catalin Marinas
2020-09-25 11:26 ` Andrey Konovalov
2020-09-25 11:47 ` Catalin Marinas
2020-09-25 11:52 ` Andrey Konovalov
2020-09-25 12:35 ` Catalin Marinas
2020-09-25 12:35 ` Catalin Marinas
2020-09-24 22:50 ` [PATCH v3 27/39] arm64: kasan: Enable in-kernel MTE Andrey Konovalov
2020-09-25 11:14 ` Catalin Marinas
2020-09-24 22:50 ` [PATCH v3 28/39] arm64: mte: Convert gcr_user into an exclude mask Andrey Konovalov
2020-09-24 22:50 ` [PATCH v3 29/39] arm64: mte: Switch GCR_EL1 in kernel entry and exit Andrey Konovalov
2020-09-25 11:34 ` Catalin Marinas
2020-09-25 11:50 ` Vincenzo Frascino
2020-09-25 12:38 ` Catalin Marinas
2020-09-24 22:50 ` [PATCH v3 30/39] arm64: kasan: Enable TBI EL1 Andrey Konovalov
2020-09-25 11:37 ` Catalin Marinas
2020-09-25 11:47 ` Vincenzo Frascino
2020-09-24 22:50 ` [PATCH v3 31/39] arm64: kasan: Align allocations for HW_TAGS Andrey Konovalov
2020-09-24 22:50 ` [PATCH v3 32/39] kasan: define KASAN_GRANULE_SIZE " Andrey Konovalov
2020-10-01 17:58 ` elver
2020-10-01 21:59 ` Andrey Konovalov
2020-09-24 22:50 ` [PATCH v3 33/39] kasan, x86, s390: update undef CONFIG_KASAN Andrey Konovalov
2020-10-01 17:59 ` elver
2020-09-24 22:50 ` [PATCH v3 34/39] kasan, arm64: expand CONFIG_KASAN checks Andrey Konovalov
2020-09-24 22:50 ` [PATCH v3 35/39] kasan, arm64: implement HW_TAGS runtime Andrey Konovalov
2020-10-01 18:00 ` elver
2020-09-24 22:50 ` [PATCH v3 36/39] kasan, arm64: print report from tag fault handler Andrey Konovalov
2020-09-25 11:39 ` Catalin Marinas
2020-09-24 22:50 ` [PATCH v3 37/39] kasan, slub: reset tags when accessing metadata Andrey Konovalov
2020-10-01 18:03 ` elver
2020-10-01 22:00 ` Andrey Konovalov
2020-09-24 22:50 ` [PATCH v3 38/39] kasan, arm64: enable CONFIG_KASAN_HW_TAGS Andrey Konovalov
2020-09-24 22:50 ` [PATCH v3 39/39] kasan: add documentation for hardware tag-based mode Andrey Konovalov
2020-10-01 18:03 ` elver
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