Commit 9f2121cb authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Stephen Rothwell
Browse files

kasan: separate metadata_fetch_row for each mode

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

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.

No functional changes for software modes.

Link: https://lkml.kernel.org/r/5fb1ec0152bb1f521505017800387ec3e36ffe18.1606161801.git.andreyknvl@google.com

Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino's avatarVincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: default avatarMarco Elver <elver@google.com>
Reviewed-by: default avatarAlexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino's avatarVincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarStephen Rothwell <sfr@canb.auug.org.au>
parent e4cdd165
......@@ -58,6 +58,13 @@
#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;
......@@ -170,6 +177,7 @@ 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);
#if defined(CONFIG_KASAN_GENERIC) && CONFIG_KASAN_STACK
void print_address_stack_frame(const void *addr);
......
......@@ -33,12 +33,6 @@
#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
......@@ -238,55 +232,59 @@ 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;
}
}
......
......@@ -123,6 +123,11 @@ 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);
}
#if CONFIG_KASAN_STACK
static bool __must_check tokenize_frame_descr(const char **frame_descr,
char *token, size_t max_tok_len,
......
......@@ -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);
......
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