2020-12-22 20:02:10 +00:00
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// SPDX-License-Identifier: GPL-2.0
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/*
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* This file contains hardware tag-based KASAN specific error reporting code.
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*
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* Copyright (c) 2020 Google, Inc.
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* Author: Andrey Konovalov <andreyknvl@google.com>
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*/
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#include <linux/kasan.h>
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#include <linux/kernel.h>
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#include <linux/memory.h>
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#include <linux/mm.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include "kasan.h"
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kasan: use internal prototypes matching gcc-13 builtins
gcc-13 warns about function definitions for builtin interfaces that have a
different prototype, e.g.:
In file included from kasan_test.c:31:
kasan.h:574:6: error: conflicting types for built-in function '__asan_register_globals'; expected 'void(void *, long int)' [-Werror=builtin-declaration-mismatch]
574 | void __asan_register_globals(struct kasan_global *globals, size_t size);
kasan.h:577:6: error: conflicting types for built-in function '__asan_alloca_poison'; expected 'void(void *, long int)' [-Werror=builtin-declaration-mismatch]
577 | void __asan_alloca_poison(unsigned long addr, size_t size);
kasan.h:580:6: error: conflicting types for built-in function '__asan_load1'; expected 'void(void *)' [-Werror=builtin-declaration-mismatch]
580 | void __asan_load1(unsigned long addr);
kasan.h:581:6: error: conflicting types for built-in function '__asan_store1'; expected 'void(void *)' [-Werror=builtin-declaration-mismatch]
581 | void __asan_store1(unsigned long addr);
kasan.h:643:6: error: conflicting types for built-in function '__hwasan_tag_memory'; expected 'void(void *, unsigned char, long int)' [-Werror=builtin-declaration-mismatch]
643 | void __hwasan_tag_memory(unsigned long addr, u8 tag, unsigned long size);
The two problems are:
- Addresses are passes as 'unsigned long' in the kernel, but gcc-13
expects a 'void *'.
- sizes meant to use a signed ssize_t rather than size_t.
Change all the prototypes to match these. Using 'void *' consistently for
addresses gets rid of a couple of type casts, so push that down to the
leaf functions where possible.
This now passes all randconfig builds on arm, arm64 and x86, but I have
not tested it on the other architectures that support kasan, since they
tend to fail randconfig builds in other ways. This might fail if any of
the 32-bit architectures expect a 'long' instead of 'int' for the size
argument.
The __asan_allocas_unpoison() function prototype is somewhat weird, since
it uses a pointer for 'stack_top' and an size_t for 'stack_bottom'. This
looks like it is meant to be 'addr' and 'size' like the others, but the
implementation clearly treats them as 'top' and 'bottom'.
Link: https://lkml.kernel.org/r/20230509145735.9263-2-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-05-09 14:57:21 +00:00
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const void *kasan_find_first_bad_addr(const void *addr, size_t size)
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2020-12-22 20:02:10 +00:00
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{
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2023-01-29 02:14:35 +00:00
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/*
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* Hardware Tag-Based KASAN only calls this function for normal memory
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* accesses, and thus addr points precisely to the first bad address
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* with an invalid (and present) memory tag. Therefore:
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* 1. Return the address as is without walking memory tags.
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* 2. Skip the addr_has_metadata check.
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*/
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2020-12-22 20:02:52 +00:00
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return kasan_reset_tag(addr);
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2020-12-22 20:02:10 +00:00
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}
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2023-01-29 02:14:35 +00:00
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size_t kasan_get_alloc_size(void *object, struct kmem_cache *cache)
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{
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size_t size = 0;
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int i = 0;
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u8 memory_tag;
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/*
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* Skip the addr_has_metadata check, as this function only operates on
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* slab memory, which must have metadata.
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*/
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/*
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* The loop below returns 0 for freed objects, for which KASAN cannot
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* calculate the allocation size based on the metadata.
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*/
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while (size < cache->object_size) {
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memory_tag = hw_get_mem_tag(object + i * KASAN_GRANULE_SIZE);
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if (memory_tag != KASAN_TAG_INVALID)
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size += KASAN_GRANULE_SIZE;
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else
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return size;
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i++;
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}
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return cache->object_size;
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}
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2021-02-24 20:05:05 +00:00
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void kasan_metadata_fetch_row(char *buffer, void *row)
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2020-12-22 20:02:10 +00:00
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{
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int i;
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for (i = 0; i < META_BYTES_PER_ROW; i++)
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buffer[i] = hw_get_mem_tag(row + i * KASAN_GRANULE_SIZE);
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}
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2021-02-24 20:05:05 +00:00
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void kasan_print_tags(u8 addr_tag, const void *addr)
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2020-12-22 20:02:10 +00:00
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{
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u8 memory_tag = hw_get_mem_tag((void *)addr);
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pr_err("Pointer tag: [%02x], memory tag: [%02x]\n",
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addr_tag, memory_tag);
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}
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