Initial import

1 files changed, 269 insertions, 0 deletions

diff --git a/mm/kasan/report.c b/mm/kasan/report.c
new file mode 100644
index 000000000..680ceedf8
--- /dev/null
+++ b/mm/kasan/report.c
@@ -0,0 +1,269 @@
+/*
+ * This file contains error reporting code.
+ *
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd.
+ * Author: Andrey Ryabinin <a.ryabinin@samsung.com>
+ *
+ * Some of code borrowed from https://github.com/xairy/linux by
+ *        Andrey Konovalov <adech.fo@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/printk.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/stacktrace.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/kasan.h>
+
+#include <asm/sections.h>
+
+#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
+
+static const void *find_first_bad_addr(const void *addr, size_t size)
+{
+	u8 shadow_val = *(u8 *)kasan_mem_to_shadow(addr);
+	const void *first_bad_addr = addr;
+
+	while (!shadow_val && first_bad_addr < addr + size) {
+		first_bad_addr += KASAN_SHADOW_SCALE_SIZE;
+		shadow_val = *(u8 *)kasan_mem_to_shadow(first_bad_addr);
+	}
+	return first_bad_addr;
+}
+
+static void print_error_description(struct kasan_access_info *info)
+{
+	const char *bug_type = "unknown crash";
+	u8 shadow_val;
+
+	info->first_bad_addr = find_first_bad_addr(info->access_addr,
+						info->access_size);
+
+	shadow_val = *(u8 *)kasan_mem_to_shadow(info->first_bad_addr);
+
+	switch (shadow_val) {
+	case KASAN_FREE_PAGE:
+	case KASAN_KMALLOC_FREE:
+		bug_type = "use after free";
+		break;
+	case KASAN_PAGE_REDZONE:
+	case KASAN_KMALLOC_REDZONE:
+	case KASAN_GLOBAL_REDZONE:
+	case 0 ... KASAN_SHADOW_SCALE_SIZE - 1:
+		bug_type = "out of bounds access";
+		break;
+	case KASAN_STACK_LEFT:
+	case KASAN_STACK_MID:
+	case KASAN_STACK_RIGHT:
+	case KASAN_STACK_PARTIAL:
+		bug_type = "out of bounds on stack";
+		break;
+	}
+
+	pr_err("BUG: KASan: %s in %pS at addr %p\n",
+		bug_type, (void *)info->ip,
+		info->access_addr);
+	pr_err("%s of size %zu by task %s/%d\n",
+		info->is_write ? "Write" : "Read",
+		info->access_size, current->comm, task_pid_nr(current));
+}
+
+static inline bool kernel_or_module_addr(const void *addr)
+{
+	return (addr >= (void *)_stext && addr < (void *)_end)
+		|| (addr >= (void *)MODULES_VADDR
+			&& addr < (void *)MODULES_END);
+}
+
+static inline bool init_task_stack_addr(const void *addr)
+{
+	return addr >= (void *)&init_thread_union.stack &&
+		(addr <= (void *)&init_thread_union.stack +
+			sizeof(init_thread_union.stack));
+}
+
+static void print_address_description(struct kasan_access_info *info)
+{
+	const void *addr = info->access_addr;
+
+	if ((addr >= (void *)PAGE_OFFSET) &&
+		(addr < high_memory)) {
+		struct page *page = virt_to_head_page(addr);
+
+		if (PageSlab(page)) {
+			void *object;
+			struct kmem_cache *cache = page->slab_cache;
+			void *last_object;
+
+			object = virt_to_obj(cache, page_address(page), addr);
+			last_object = page_address(page) +
+				page->objects * cache->size;
+
+			if (unlikely(object > last_object))
+				object = last_object; /* we hit into padding */
+
+			object_err(cache, page, object,
+				"kasan: bad access detected");
+			return;
+		}
+		dump_page(page, "kasan: bad access detected");
+	}
+
+	if (kernel_or_module_addr(addr)) {
+		if (!init_task_stack_addr(addr))
+			pr_err("Address belongs to variable %pS\n", addr);
+	}
+
+	dump_stack();
+}
+
+static bool row_is_guilty(const void *row, const void *guilty)
+{
+	return (row <= guilty) && (guilty < row + SHADOW_BYTES_PER_ROW);
+}
+
+static int shadow_pointer_offset(const void *row, const void *shadow)
+{
+	/* The length of ">ff00ff00ff00ff00: " is
+	 *    3 + (BITS_PER_LONG/8)*2 chars.
+	 */
+	return 3 + (BITS_PER_LONG/8)*2 + (shadow - row)*2 +
+		(shadow - row) / SHADOW_BYTES_PER_BLOCK + 1;
+}
+
+static void print_shadow_for_address(const void *addr)
+{
+	int i;
+	const void *shadow = kasan_mem_to_shadow(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;
+
+	pr_err("Memory state around the buggy address:\n");
+
+	for (i = -SHADOW_ROWS_AROUND_ADDR; i <= SHADOW_ROWS_AROUND_ADDR; i++) {
+		const void *kaddr = kasan_shadow_to_mem(shadow_row);
+		char buffer[4 + (BITS_PER_LONG/8)*2];
+
+		snprintf(buffer, sizeof(buffer),
+			(i == 0) ? ">%p: " : " %p: ", kaddr);
+
+		kasan_disable_current();
+		print_hex_dump(KERN_ERR, buffer,
+			DUMP_PREFIX_NONE, SHADOW_BYTES_PER_ROW, 1,
+			shadow_row, SHADOW_BYTES_PER_ROW, 0);
+		kasan_enable_current();
+
+		if (row_is_guilty(shadow_row, shadow))
+			pr_err("%*c\n",
+				shadow_pointer_offset(shadow_row, shadow),
+				'^');
+
+		shadow_row += SHADOW_BYTES_PER_ROW;
+	}
+}
+
+static DEFINE_SPINLOCK(report_lock);
+
+void kasan_report_error(struct kasan_access_info *info)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&report_lock, flags);
+	pr_err("================================="
+		"=================================\n");
+	print_error_description(info);
+	print_address_description(info);
+	print_shadow_for_address(info->first_bad_addr);
+	pr_err("================================="
+		"=================================\n");
+	spin_unlock_irqrestore(&report_lock, flags);
+}
+
+void kasan_report_user_access(struct kasan_access_info *info)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&report_lock, flags);
+	pr_err("================================="
+		"=================================\n");
+	pr_err("BUG: KASan: user-memory-access on address %p\n",
+		info->access_addr);
+	pr_err("%s of size %zu by task %s/%d\n",
+		info->is_write ? "Write" : "Read",
+		info->access_size, current->comm, task_pid_nr(current));
+	dump_stack();
+	pr_err("================================="
+		"=================================\n");
+	spin_unlock_irqrestore(&report_lock, flags);
+}
+
+void kasan_report(unsigned long addr, size_t size,
+		bool is_write, unsigned long ip)
+{
+	struct kasan_access_info info;
+
+	if (likely(!kasan_enabled()))
+		return;
+
+	info.access_addr = (void *)addr;
+	info.access_size = size;
+	info.is_write = is_write;
+	info.ip = ip;
+	kasan_report_error(&info);
+}
+
+
+#define DEFINE_ASAN_REPORT_LOAD(size)                     \
+void __asan_report_load##size##_noabort(unsigned long addr) \
+{                                                         \
+	kasan_report(addr, size, false, _RET_IP_);	  \
+}                                                         \
+EXPORT_SYMBOL(__asan_report_load##size##_noabort)
+
+#define DEFINE_ASAN_REPORT_STORE(size)                     \
+void __asan_report_store##size##_noabort(unsigned long addr) \
+{                                                          \
+	kasan_report(addr, size, true, _RET_IP_);	   \
+}                                                          \
+EXPORT_SYMBOL(__asan_report_store##size##_noabort)
+
+DEFINE_ASAN_REPORT_LOAD(1);
+DEFINE_ASAN_REPORT_LOAD(2);
+DEFINE_ASAN_REPORT_LOAD(4);
+DEFINE_ASAN_REPORT_LOAD(8);
+DEFINE_ASAN_REPORT_LOAD(16);
+DEFINE_ASAN_REPORT_STORE(1);
+DEFINE_ASAN_REPORT_STORE(2);
+DEFINE_ASAN_REPORT_STORE(4);
+DEFINE_ASAN_REPORT_STORE(8);
+DEFINE_ASAN_REPORT_STORE(16);
+
+void __asan_report_load_n_noabort(unsigned long addr, size_t size)
+{
+	kasan_report(addr, size, false, _RET_IP_);
+}
+EXPORT_SYMBOL(__asan_report_load_n_noabort);
+
+void __asan_report_store_n_noabort(unsigned long addr, size_t size)
+{
+	kasan_report(addr, size, true, _RET_IP_);
+}
+EXPORT_SYMBOL(__asan_report_store_n_noabort);