2020-11-10 22:17:15

by Andrey Konovalov

[permalink] [raw]
Subject: [PATCH v9 22/44] kasan: rename SHADOW layout macros to META

This is a preparatory commit for the upcoming addition of a new hardware
tag-based (MTE-based) KASAN mode.

Hardware tag-based KASAN won't be using shadow memory, but will reuse
these macros. Rename "SHADOW" to implementation-neutral "META".

No functional changes.

Signed-off-by: Andrey Konovalov <[email protected]>
Signed-off-by: Vincenzo Frascino <[email protected]>
Reviewed-by: Marco Elver <[email protected]>
---
Change-Id: Id2d836bf43b401bce1221cc06e745185f17b1cc
---
mm/kasan/report.c | 30 +++++++++++++++---------------
1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 594bad2a3a5e..8c588588c88f 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -33,11 +33,11 @@
#include "kasan.h"
#include "../slab.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
+/* 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;

@@ -240,7 +240,7 @@ static void print_address_description(void *addr, u8 tag)

static bool row_is_guilty(const void *row, const void *guilty)
{
- return (row <= guilty) && (guilty < row + SHADOW_BYTES_PER_ROW);
+ return (row <= guilty) && (guilty < row + META_BYTES_PER_ROW);
}

static int shadow_pointer_offset(const void *row, const void *shadow)
@@ -249,7 +249,7 @@ static int shadow_pointer_offset(const void *row, const void *shadow)
* 3 + (BITS_PER_LONG/8)*2 chars.
*/
return 3 + (BITS_PER_LONG/8)*2 + (shadow - row)*2 +
- (shadow - row) / SHADOW_BYTES_PER_BLOCK + 1;
+ (shadow - row) / META_BYTES_PER_BLOCK + 1;
}

static void print_memory_metadata(const void *addr)
@@ -259,15 +259,15 @@ static void print_memory_metadata(const void *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;
+ META_BYTES_PER_ROW)
+ - META_ROWS_AROUND_ADDR * META_BYTES_PER_ROW;

pr_err("Memory state around the buggy address:\n");

- for (i = -SHADOW_ROWS_AROUND_ADDR; i <= SHADOW_ROWS_AROUND_ADDR; i++) {
+ 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[SHADOW_BYTES_PER_ROW];
+ char shadow_buf[META_BYTES_PER_ROW];

snprintf(buffer, sizeof(buffer),
(i == 0) ? ">%px: " : " %px: ", kaddr);
@@ -276,17 +276,17 @@ static void print_memory_metadata(const void *addr)
* function, because generic functions may try to
* access kasan mapping for the passed address.
*/
- memcpy(shadow_buf, shadow_row, SHADOW_BYTES_PER_ROW);
+ memcpy(shadow_buf, shadow_row, META_BYTES_PER_ROW);
print_hex_dump(KERN_ERR, buffer,
- DUMP_PREFIX_NONE, SHADOW_BYTES_PER_ROW, 1,
- shadow_buf, SHADOW_BYTES_PER_ROW, 0);
+ DUMP_PREFIX_NONE, META_BYTES_PER_ROW, 1,
+ shadow_buf, META_BYTES_PER_ROW, 0);

if (row_is_guilty(shadow_row, shadow))
pr_err("%*c\n",
shadow_pointer_offset(shadow_row, shadow),
'^');

- shadow_row += SHADOW_BYTES_PER_ROW;
+ shadow_row += META_BYTES_PER_ROW;
}
}

--
2.29.2.222.g5d2a92d10f8-goog


2020-11-11 15:23:50

by Alexander Potapenko

[permalink] [raw]
Subject: Re: [PATCH v9 22/44] kasan: rename SHADOW layout macros to META

On Tue, Nov 10, 2020 at 11:12 PM Andrey Konovalov <[email protected]> wrote:
>
> This is a preparatory commit for the upcoming addition of a new hardware
> tag-based (MTE-based) KASAN mode.
>
> Hardware tag-based KASAN won't be using shadow memory, but will reuse
> these macros. Rename "SHADOW" to implementation-neutral "META".
>
> No functional changes.
>
> Signed-off-by: Andrey Konovalov <[email protected]>
> Signed-off-by: Vincenzo Frascino <[email protected]>
> Reviewed-by: Marco Elver <[email protected]>
Reviewed-by: Alexander Potapenko <[email protected]>

> ---
> Change-Id: Id2d836bf43b401bce1221cc06e745185f17b1cc
> ---
> mm/kasan/report.c | 30 +++++++++++++++---------------
> 1 file changed, 15 insertions(+), 15 deletions(-)
>
> diff --git a/mm/kasan/report.c b/mm/kasan/report.c
> index 594bad2a3a5e..8c588588c88f 100644
> --- a/mm/kasan/report.c
> +++ b/mm/kasan/report.c
> @@ -33,11 +33,11 @@
> #include "kasan.h"
> #include "../slab.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
> +/* 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;
>
> @@ -240,7 +240,7 @@ static void print_address_description(void *addr, u8 tag)
>
> static bool row_is_guilty(const void *row, const void *guilty)
> {
> - return (row <= guilty) && (guilty < row + SHADOW_BYTES_PER_ROW);
> + return (row <= guilty) && (guilty < row + META_BYTES_PER_ROW);
> }
>
> static int shadow_pointer_offset(const void *row, const void *shadow)
> @@ -249,7 +249,7 @@ static int shadow_pointer_offset(const void *row, const void *shadow)
> * 3 + (BITS_PER_LONG/8)*2 chars.
> */
> return 3 + (BITS_PER_LONG/8)*2 + (shadow - row)*2 +
> - (shadow - row) / SHADOW_BYTES_PER_BLOCK + 1;
> + (shadow - row) / META_BYTES_PER_BLOCK + 1;
> }
>
> static void print_memory_metadata(const void *addr)
> @@ -259,15 +259,15 @@ static void print_memory_metadata(const void *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;
> + META_BYTES_PER_ROW)
> + - META_ROWS_AROUND_ADDR * META_BYTES_PER_ROW;
>
> pr_err("Memory state around the buggy address:\n");
>
> - for (i = -SHADOW_ROWS_AROUND_ADDR; i <= SHADOW_ROWS_AROUND_ADDR; i++) {
> + 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[SHADOW_BYTES_PER_ROW];
> + char shadow_buf[META_BYTES_PER_ROW];
>
> snprintf(buffer, sizeof(buffer),
> (i == 0) ? ">%px: " : " %px: ", kaddr);
> @@ -276,17 +276,17 @@ static void print_memory_metadata(const void *addr)
> * function, because generic functions may try to
> * access kasan mapping for the passed address.
> */
> - memcpy(shadow_buf, shadow_row, SHADOW_BYTES_PER_ROW);
> + memcpy(shadow_buf, shadow_row, META_BYTES_PER_ROW);
> print_hex_dump(KERN_ERR, buffer,
> - DUMP_PREFIX_NONE, SHADOW_BYTES_PER_ROW, 1,
> - shadow_buf, SHADOW_BYTES_PER_ROW, 0);
> + DUMP_PREFIX_NONE, META_BYTES_PER_ROW, 1,
> + shadow_buf, META_BYTES_PER_ROW, 0);
>
> if (row_is_guilty(shadow_row, shadow))
> pr_err("%*c\n",
> shadow_pointer_offset(shadow_row, shadow),
> '^');
>
> - shadow_row += SHADOW_BYTES_PER_ROW;
> + shadow_row += META_BYTES_PER_ROW;
> }
> }
>
> --
> 2.29.2.222.g5d2a92d10f8-goog
>


--
Alexander Potapenko
Software Engineer

Google Germany GmbH
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