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327 lines
8.5 KiB
327 lines
8.5 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* This file contains generic KASAN specific error reporting code. |
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* |
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* Copyright (c) 2014 Samsung Electronics Co., Ltd. |
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* Author: Andrey Ryabinin <[email protected]> |
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* |
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* Some code borrowed from https://github.com/xairy/kasan-prototype by |
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* Andrey Konovalov <[email protected]> |
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*/ |
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#include <linux/bitops.h> |
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#include <linux/ftrace.h> |
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#include <linux/init.h> |
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#include <linux/kernel.h> |
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#include <linux/mm.h> |
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#include <linux/printk.h> |
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#include <linux/sched.h> |
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#include <linux/sched/task_stack.h> |
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#include <linux/slab.h> |
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#include <linux/stackdepot.h> |
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#include <linux/stacktrace.h> |
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#include <linux/string.h> |
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#include <linux/types.h> |
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#include <linux/kasan.h> |
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#include <linux/module.h> |
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#include <asm/sections.h> |
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#include "kasan.h" |
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#include "../slab.h" |
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void *kasan_find_first_bad_addr(void *addr, size_t size) |
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{ |
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void *p = addr; |
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while (p < addr + size && !(*(u8 *)kasan_mem_to_shadow(p))) |
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p += KASAN_GRANULE_SIZE; |
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return p; |
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} |
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static const char *get_shadow_bug_type(struct kasan_access_info *info) |
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{ |
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const char *bug_type = "unknown-crash"; |
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u8 *shadow_addr; |
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shadow_addr = (u8 *)kasan_mem_to_shadow(info->first_bad_addr); |
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/* |
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* If shadow byte value is in [0, KASAN_GRANULE_SIZE) we can look |
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* at the next shadow byte to determine the type of the bad access. |
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*/ |
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if (*shadow_addr > 0 && *shadow_addr <= KASAN_GRANULE_SIZE - 1) |
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shadow_addr++; |
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switch (*shadow_addr) { |
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case 0 ... KASAN_GRANULE_SIZE - 1: |
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/* |
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* In theory it's still possible to see these shadow values |
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* due to a data race in the kernel code. |
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*/ |
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bug_type = "out-of-bounds"; |
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break; |
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case KASAN_PAGE_REDZONE: |
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case KASAN_KMALLOC_REDZONE: |
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bug_type = "slab-out-of-bounds"; |
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break; |
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case KASAN_GLOBAL_REDZONE: |
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bug_type = "global-out-of-bounds"; |
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break; |
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case KASAN_STACK_LEFT: |
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case KASAN_STACK_MID: |
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case KASAN_STACK_RIGHT: |
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case KASAN_STACK_PARTIAL: |
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bug_type = "stack-out-of-bounds"; |
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break; |
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case KASAN_FREE_PAGE: |
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case KASAN_KMALLOC_FREE: |
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case KASAN_KMALLOC_FREETRACK: |
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bug_type = "use-after-free"; |
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break; |
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case KASAN_ALLOCA_LEFT: |
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case KASAN_ALLOCA_RIGHT: |
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bug_type = "alloca-out-of-bounds"; |
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break; |
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case KASAN_VMALLOC_INVALID: |
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bug_type = "vmalloc-out-of-bounds"; |
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break; |
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} |
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return bug_type; |
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} |
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static const char *get_wild_bug_type(struct kasan_access_info *info) |
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{ |
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const char *bug_type = "unknown-crash"; |
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if ((unsigned long)info->access_addr < PAGE_SIZE) |
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bug_type = "null-ptr-deref"; |
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else if ((unsigned long)info->access_addr < TASK_SIZE) |
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bug_type = "user-memory-access"; |
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else |
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bug_type = "wild-memory-access"; |
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return bug_type; |
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} |
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const char *kasan_get_bug_type(struct kasan_access_info *info) |
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{ |
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/* |
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* If access_size is a negative number, then it has reason to be |
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* defined as out-of-bounds bug type. |
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* |
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* Casting negative numbers to size_t would indeed turn up as |
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* a large size_t and its value will be larger than ULONG_MAX/2, |
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* so that this can qualify as out-of-bounds. |
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*/ |
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if (info->access_addr + info->access_size < info->access_addr) |
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return "out-of-bounds"; |
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if (addr_has_metadata(info->access_addr)) |
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return get_shadow_bug_type(info); |
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return get_wild_bug_type(info); |
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} |
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void kasan_metadata_fetch_row(char *buffer, void *row) |
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{ |
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memcpy(buffer, kasan_mem_to_shadow(row), META_BYTES_PER_ROW); |
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} |
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#ifdef CONFIG_KASAN_STACK |
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static bool __must_check tokenize_frame_descr(const char **frame_descr, |
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char *token, size_t max_tok_len, |
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unsigned long *value) |
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{ |
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const char *sep = strchr(*frame_descr, ' '); |
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if (sep == NULL) |
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sep = *frame_descr + strlen(*frame_descr); |
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if (token != NULL) { |
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const size_t tok_len = sep - *frame_descr; |
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if (tok_len + 1 > max_tok_len) { |
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pr_err("KASAN internal error: frame description too long: %s\n", |
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*frame_descr); |
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return false; |
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} |
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/* Copy token (+ 1 byte for '\0'). */ |
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strlcpy(token, *frame_descr, tok_len + 1); |
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} |
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/* Advance frame_descr past separator. */ |
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*frame_descr = sep + 1; |
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if (value != NULL && kstrtoul(token, 10, value)) { |
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pr_err("KASAN internal error: not a valid number: %s\n", token); |
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return false; |
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} |
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return true; |
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} |
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static void print_decoded_frame_descr(const char *frame_descr) |
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{ |
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/* |
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* We need to parse the following string: |
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* "n alloc_1 alloc_2 ... alloc_n" |
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* where alloc_i looks like |
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* "offset size len name" |
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* or "offset size len name:line". |
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*/ |
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char token[64]; |
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unsigned long num_objects; |
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if (!tokenize_frame_descr(&frame_descr, token, sizeof(token), |
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&num_objects)) |
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return; |
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pr_err("\n"); |
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pr_err("this frame has %lu %s:\n", num_objects, |
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num_objects == 1 ? "object" : "objects"); |
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while (num_objects--) { |
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unsigned long offset; |
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unsigned long size; |
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/* access offset */ |
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if (!tokenize_frame_descr(&frame_descr, token, sizeof(token), |
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&offset)) |
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return; |
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/* access size */ |
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if (!tokenize_frame_descr(&frame_descr, token, sizeof(token), |
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&size)) |
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return; |
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/* name length (unused) */ |
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if (!tokenize_frame_descr(&frame_descr, NULL, 0, NULL)) |
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return; |
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/* object name */ |
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if (!tokenize_frame_descr(&frame_descr, token, sizeof(token), |
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NULL)) |
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return; |
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/* Strip line number; without filename it's not very helpful. */ |
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strreplace(token, ':', '\0'); |
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/* Finally, print object information. */ |
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pr_err(" [%lu, %lu) '%s'", offset, offset + size, token); |
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} |
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} |
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static bool __must_check get_address_stack_frame_info(const void *addr, |
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unsigned long *offset, |
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const char **frame_descr, |
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const void **frame_pc) |
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{ |
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unsigned long aligned_addr; |
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unsigned long mem_ptr; |
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const u8 *shadow_bottom; |
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const u8 *shadow_ptr; |
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const unsigned long *frame; |
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BUILD_BUG_ON(IS_ENABLED(CONFIG_STACK_GROWSUP)); |
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/* |
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* NOTE: We currently only support printing frame information for |
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* accesses to the task's own stack. |
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*/ |
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if (!object_is_on_stack(addr)) |
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return false; |
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aligned_addr = round_down((unsigned long)addr, sizeof(long)); |
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mem_ptr = round_down(aligned_addr, KASAN_GRANULE_SIZE); |
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shadow_ptr = kasan_mem_to_shadow((void *)aligned_addr); |
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shadow_bottom = kasan_mem_to_shadow(end_of_stack(current)); |
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while (shadow_ptr >= shadow_bottom && *shadow_ptr != KASAN_STACK_LEFT) { |
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shadow_ptr--; |
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mem_ptr -= KASAN_GRANULE_SIZE; |
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} |
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while (shadow_ptr >= shadow_bottom && *shadow_ptr == KASAN_STACK_LEFT) { |
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shadow_ptr--; |
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mem_ptr -= KASAN_GRANULE_SIZE; |
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} |
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if (shadow_ptr < shadow_bottom) |
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return false; |
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frame = (const unsigned long *)(mem_ptr + KASAN_GRANULE_SIZE); |
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if (frame[0] != KASAN_CURRENT_STACK_FRAME_MAGIC) { |
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pr_err("KASAN internal error: frame info validation failed; invalid marker: %lu\n", |
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frame[0]); |
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return false; |
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} |
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*offset = (unsigned long)addr - (unsigned long)frame; |
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*frame_descr = (const char *)frame[1]; |
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*frame_pc = (void *)frame[2]; |
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return true; |
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} |
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void kasan_print_address_stack_frame(const void *addr) |
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{ |
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unsigned long offset; |
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const char *frame_descr; |
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const void *frame_pc; |
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if (!get_address_stack_frame_info(addr, &offset, &frame_descr, |
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&frame_pc)) |
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return; |
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/* |
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* get_address_stack_frame_info only returns true if the given addr is |
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* on the current task's stack. |
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*/ |
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pr_err("\n"); |
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pr_err("addr %px is located in stack of task %s/%d at offset %lu in frame:\n", |
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addr, current->comm, task_pid_nr(current), offset); |
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pr_err(" %pS\n", frame_pc); |
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if (!frame_descr) |
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return; |
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print_decoded_frame_descr(frame_descr); |
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} |
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#endif /* CONFIG_KASAN_STACK */ |
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#define DEFINE_ASAN_REPORT_LOAD(size) \ |
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void __asan_report_load##size##_noabort(unsigned long addr) \ |
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{ \ |
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kasan_report(addr, size, false, _RET_IP_); \ |
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} \ |
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EXPORT_SYMBOL(__asan_report_load##size##_noabort) |
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#define DEFINE_ASAN_REPORT_STORE(size) \ |
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void __asan_report_store##size##_noabort(unsigned long addr) \ |
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{ \ |
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kasan_report(addr, size, true, _RET_IP_); \ |
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} \ |
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EXPORT_SYMBOL(__asan_report_store##size##_noabort) |
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DEFINE_ASAN_REPORT_LOAD(1); |
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DEFINE_ASAN_REPORT_LOAD(2); |
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DEFINE_ASAN_REPORT_LOAD(4); |
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DEFINE_ASAN_REPORT_LOAD(8); |
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DEFINE_ASAN_REPORT_LOAD(16); |
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DEFINE_ASAN_REPORT_STORE(1); |
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DEFINE_ASAN_REPORT_STORE(2); |
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DEFINE_ASAN_REPORT_STORE(4); |
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DEFINE_ASAN_REPORT_STORE(8); |
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DEFINE_ASAN_REPORT_STORE(16); |
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void __asan_report_load_n_noabort(unsigned long addr, size_t size) |
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{ |
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kasan_report(addr, size, false, _RET_IP_); |
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} |
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EXPORT_SYMBOL(__asan_report_load_n_noabort); |
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void __asan_report_store_n_noabort(unsigned long addr, size_t size) |
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{ |
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kasan_report(addr, size, true, _RET_IP_); |
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} |
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EXPORT_SYMBOL(__asan_report_store_n_noabort);
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