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![Andrey Ryabinin](/assets/img/avatar_default.png)
Update my email address. Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
269 lines
7.3 KiB
C
269 lines
7.3 KiB
C
/*
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* This file contains 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 <ryabinin.a.a@gmail.com>
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*
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* Some of code borrowed from https://github.com/xairy/linux by
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* Andrey Konovalov <adech.fo@gmail.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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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/slab.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 <asm/sections.h>
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#include "kasan.h"
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#include "../slab.h"
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/* Shadow layout customization. */
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#define SHADOW_BYTES_PER_BLOCK 1
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#define SHADOW_BLOCKS_PER_ROW 16
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#define SHADOW_BYTES_PER_ROW (SHADOW_BLOCKS_PER_ROW * SHADOW_BYTES_PER_BLOCK)
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#define SHADOW_ROWS_AROUND_ADDR 2
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static const void *find_first_bad_addr(const void *addr, size_t size)
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{
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u8 shadow_val = *(u8 *)kasan_mem_to_shadow(addr);
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const void *first_bad_addr = addr;
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while (!shadow_val && first_bad_addr < addr + size) {
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first_bad_addr += KASAN_SHADOW_SCALE_SIZE;
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shadow_val = *(u8 *)kasan_mem_to_shadow(first_bad_addr);
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}
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return first_bad_addr;
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}
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static void print_error_description(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_val;
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info->first_bad_addr = find_first_bad_addr(info->access_addr,
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info->access_size);
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shadow_val = *(u8 *)kasan_mem_to_shadow(info->first_bad_addr);
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switch (shadow_val) {
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case KASAN_FREE_PAGE:
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case KASAN_KMALLOC_FREE:
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bug_type = "use after free";
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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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case KASAN_GLOBAL_REDZONE:
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case 0 ... KASAN_SHADOW_SCALE_SIZE - 1:
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bug_type = "out of bounds access";
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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 = "out of bounds on stack";
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break;
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}
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pr_err("BUG: KASan: %s in %pS at addr %p\n",
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bug_type, (void *)info->ip,
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info->access_addr);
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pr_err("%s of size %zu by task %s/%d\n",
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info->is_write ? "Write" : "Read",
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info->access_size, current->comm, task_pid_nr(current));
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}
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static inline bool kernel_or_module_addr(const void *addr)
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{
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return (addr >= (void *)_stext && addr < (void *)_end)
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|| (addr >= (void *)MODULES_VADDR
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&& addr < (void *)MODULES_END);
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}
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static inline bool init_task_stack_addr(const void *addr)
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{
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return addr >= (void *)&init_thread_union.stack &&
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(addr <= (void *)&init_thread_union.stack +
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sizeof(init_thread_union.stack));
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}
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static void print_address_description(struct kasan_access_info *info)
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{
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const void *addr = info->access_addr;
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if ((addr >= (void *)PAGE_OFFSET) &&
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(addr < high_memory)) {
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struct page *page = virt_to_head_page(addr);
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if (PageSlab(page)) {
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void *object;
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struct kmem_cache *cache = page->slab_cache;
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void *last_object;
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object = virt_to_obj(cache, page_address(page), addr);
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last_object = page_address(page) +
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page->objects * cache->size;
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if (unlikely(object > last_object))
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object = last_object; /* we hit into padding */
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object_err(cache, page, object,
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"kasan: bad access detected");
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return;
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}
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dump_page(page, "kasan: bad access detected");
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}
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if (kernel_or_module_addr(addr)) {
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if (!init_task_stack_addr(addr))
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pr_err("Address belongs to variable %pS\n", addr);
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}
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dump_stack();
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}
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static bool row_is_guilty(const void *row, const void *guilty)
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{
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return (row <= guilty) && (guilty < row + SHADOW_BYTES_PER_ROW);
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}
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static int shadow_pointer_offset(const void *row, const void *shadow)
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{
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/* The length of ">ff00ff00ff00ff00: " is
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* 3 + (BITS_PER_LONG/8)*2 chars.
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*/
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return 3 + (BITS_PER_LONG/8)*2 + (shadow - row)*2 +
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(shadow - row) / SHADOW_BYTES_PER_BLOCK + 1;
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}
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static void print_shadow_for_address(const void *addr)
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{
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int i;
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const void *shadow = kasan_mem_to_shadow(addr);
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const void *shadow_row;
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shadow_row = (void *)round_down((unsigned long)shadow,
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SHADOW_BYTES_PER_ROW)
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- SHADOW_ROWS_AROUND_ADDR * SHADOW_BYTES_PER_ROW;
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pr_err("Memory state around the buggy address:\n");
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for (i = -SHADOW_ROWS_AROUND_ADDR; i <= SHADOW_ROWS_AROUND_ADDR; i++) {
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const void *kaddr = kasan_shadow_to_mem(shadow_row);
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char buffer[4 + (BITS_PER_LONG/8)*2];
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snprintf(buffer, sizeof(buffer),
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(i == 0) ? ">%p: " : " %p: ", kaddr);
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kasan_disable_current();
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print_hex_dump(KERN_ERR, buffer,
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DUMP_PREFIX_NONE, SHADOW_BYTES_PER_ROW, 1,
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shadow_row, SHADOW_BYTES_PER_ROW, 0);
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kasan_enable_current();
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if (row_is_guilty(shadow_row, shadow))
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pr_err("%*c\n",
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shadow_pointer_offset(shadow_row, shadow),
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'^');
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shadow_row += SHADOW_BYTES_PER_ROW;
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}
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}
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static DEFINE_SPINLOCK(report_lock);
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void kasan_report_error(struct kasan_access_info *info)
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{
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unsigned long flags;
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spin_lock_irqsave(&report_lock, flags);
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pr_err("================================="
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"=================================\n");
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print_error_description(info);
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print_address_description(info);
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print_shadow_for_address(info->first_bad_addr);
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pr_err("================================="
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"=================================\n");
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spin_unlock_irqrestore(&report_lock, flags);
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}
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void kasan_report_user_access(struct kasan_access_info *info)
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{
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unsigned long flags;
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spin_lock_irqsave(&report_lock, flags);
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pr_err("================================="
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"=================================\n");
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pr_err("BUG: KASan: user-memory-access on address %p\n",
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info->access_addr);
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pr_err("%s of size %zu by task %s/%d\n",
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info->is_write ? "Write" : "Read",
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info->access_size, current->comm, task_pid_nr(current));
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dump_stack();
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pr_err("================================="
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"=================================\n");
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spin_unlock_irqrestore(&report_lock, flags);
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}
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void kasan_report(unsigned long addr, size_t size,
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bool is_write, unsigned long ip)
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{
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struct kasan_access_info info;
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if (likely(!kasan_enabled()))
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return;
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info.access_addr = (void *)addr;
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info.access_size = size;
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info.is_write = is_write;
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info.ip = ip;
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kasan_report_error(&info);
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}
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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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