1 files changed, 73 insertions, 199 deletions

diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 5c169aa688fd..ca9418fe9232 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -1,5 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
- * This file contains error reporting code.
+ * This file contains common generic and tag-based KASAN error reporting code.
  *
  * Copyright (c) 2014 Samsung Electronics Co., Ltd.
  * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
@@ -39,129 +40,43 @@
 #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 unsigned long kasan_flags;
 
-static bool addr_has_shadow(struct kasan_access_info *info)
-{
-	return (info->access_addr >=
-		kasan_shadow_to_mem((void *)KASAN_SHADOW_START));
-}
+#define KASAN_BIT_REPORTED	0
+#define KASAN_BIT_MULTI_SHOT	1
 
-static const char *get_shadow_bug_type(struct kasan_access_info *info)
+bool kasan_save_enable_multi_shot(void)
 {
-	const char *bug_type = "unknown-crash";
-	u8 *shadow_addr;
-
-	info->first_bad_addr = find_first_bad_addr(info->access_addr,
-						info->access_size);
-
-	shadow_addr = (u8 *)kasan_mem_to_shadow(info->first_bad_addr);
-
-	/*
-	 * If shadow byte value is in [0, KASAN_SHADOW_SCALE_SIZE) we can look
-	 * at the next shadow byte to determine the type of the bad access.
-	 */
-	if (*shadow_addr > 0 && *shadow_addr <= KASAN_SHADOW_SCALE_SIZE - 1)
-		shadow_addr++;
-
-	switch (*shadow_addr) {
-	case 0 ... KASAN_SHADOW_SCALE_SIZE - 1:
-		/*
-		 * In theory it's still possible to see these shadow values
-		 * due to a data race in the kernel code.
-		 */
-		bug_type = "out-of-bounds";
-		break;
-	case KASAN_PAGE_REDZONE:
-	case KASAN_KMALLOC_REDZONE:
-		bug_type = "slab-out-of-bounds";
-		break;
-	case KASAN_GLOBAL_REDZONE:
-		bug_type = "global-out-of-bounds";
-		break;
-	case KASAN_STACK_LEFT:
-	case KASAN_STACK_MID:
-	case KASAN_STACK_RIGHT:
-	case KASAN_STACK_PARTIAL:
-		bug_type = "stack-out-of-bounds";
-		break;
-	case KASAN_FREE_PAGE:
-	case KASAN_KMALLOC_FREE:
-		bug_type = "use-after-free";
-		break;
-	case KASAN_USE_AFTER_SCOPE:
-		bug_type = "use-after-scope";
-		break;
-	case KASAN_ALLOCA_LEFT:
-	case KASAN_ALLOCA_RIGHT:
-		bug_type = "alloca-out-of-bounds";
-		break;
-	}
-
-	return bug_type;
+	return test_and_set_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags);
 }
+EXPORT_SYMBOL_GPL(kasan_save_enable_multi_shot);
 
-static const char *get_wild_bug_type(struct kasan_access_info *info)
+void kasan_restore_multi_shot(bool enabled)
 {
-	const char *bug_type = "unknown-crash";
-
-	if ((unsigned long)info->access_addr < PAGE_SIZE)
-		bug_type = "null-ptr-deref";
-	else if ((unsigned long)info->access_addr < TASK_SIZE)
-		bug_type = "user-memory-access";
-	else
-		bug_type = "wild-memory-access";
-
-	return bug_type;
+	if (!enabled)
+		clear_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags);
 }
+EXPORT_SYMBOL_GPL(kasan_restore_multi_shot);
 
-static const char *get_bug_type(struct kasan_access_info *info)
+static int __init kasan_set_multi_shot(char *str)
 {
-	if (addr_has_shadow(info))
-		return get_shadow_bug_type(info);
-	return get_wild_bug_type(info);
+	set_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags);
+	return 1;
 }
+__setup("kasan_multi_shot", kasan_set_multi_shot);
 
 static void print_error_description(struct kasan_access_info *info)
 {
-	const char *bug_type = get_bug_type(info);
-
 	pr_err("BUG: KASAN: %s in %pS\n",
-		bug_type, (void *)info->ip);
+		get_bug_type(info), (void *)info->ip);
 	pr_err("%s of size %zu at addr %px by task %s/%d\n",
 		info->is_write ? "Write" : "Read", info->access_size,
 		info->access_addr, current->comm, task_pid_nr(current));
 }
 
-static inline bool kernel_or_module_addr(const void *addr)
-{
-	if (addr >= (void *)_stext && addr < (void *)_end)
-		return true;
-	if (is_module_address((unsigned long)addr))
-		return true;
-	return false;
-}
-
-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 DEFINE_SPINLOCK(report_lock);
 
-static void kasan_start_report(unsigned long *flags)
+static void start_report(unsigned long *flags)
 {
 	/*
 	 * Make sure we don't end up in loop.
@@ -171,7 +86,7 @@ static void kasan_start_report(unsigned long *flags)
 	pr_err("==================================================================\n");
 }
 
-static void kasan_end_report(unsigned long *flags)
+static void end_report(unsigned long *flags)
 {
 	pr_err("==================================================================\n");
 	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
@@ -249,6 +164,22 @@ static void describe_object(struct kmem_cache *cache, void *object,
 	describe_object_addr(cache, object, addr);
 }
 
+static inline bool kernel_or_module_addr(const void *addr)
+{
+	if (addr >= (void *)_stext && addr < (void *)_end)
+		return true;
+	if (is_module_address((unsigned long)addr))
+		return true;
+	return false;
+}
+
+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(void *addr)
 {
 	struct page *page = addr_to_page(addr);
@@ -326,126 +257,69 @@ static void print_shadow_for_address(const void *addr)
 	}
 }
 
+static bool report_enabled(void)
+{
+	if (current->kasan_depth)
+		return false;
+	if (test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags))
+		return true;
+	return !test_and_set_bit(KASAN_BIT_REPORTED, &kasan_flags);
+}
+
 void kasan_report_invalid_free(void *object, unsigned long ip)
 {
 	unsigned long flags;
 
-	kasan_start_report(&flags);
+	start_report(&flags);
 	pr_err("BUG: KASAN: double-free or invalid-free in %pS\n", (void *)ip);
+	print_tags(get_tag(object), reset_tag(object));
+	object = reset_tag(object);
 	pr_err("\n");
 	print_address_description(object);
 	pr_err("\n");
 	print_shadow_for_address(object);
-	kasan_end_report(&flags);
-}
-
-static void kasan_report_error(struct kasan_access_info *info)
-{
-	unsigned long flags;
-
-	kasan_start_report(&flags);
-
-	print_error_description(info);
-	pr_err("\n");
-
-	if (!addr_has_shadow(info)) {
-		dump_stack();
-	} else {
-		print_address_description((void *)info->access_addr);
-		pr_err("\n");
-		print_shadow_for_address(info->first_bad_addr);
-	}
-
-	kasan_end_report(&flags);
-}
-
-static unsigned long kasan_flags;
-
-#define KASAN_BIT_REPORTED	0
-#define KASAN_BIT_MULTI_SHOT	1
-
-bool kasan_save_enable_multi_shot(void)
-{
-	return test_and_set_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags);
-}
-EXPORT_SYMBOL_GPL(kasan_save_enable_multi_shot);
-
-void kasan_restore_multi_shot(bool enabled)
-{
-	if (!enabled)
-		clear_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags);
-}
-EXPORT_SYMBOL_GPL(kasan_restore_multi_shot);
-
-static int __init kasan_set_multi_shot(char *str)
-{
-	set_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags);
-	return 1;
-}
-__setup("kasan_multi_shot", kasan_set_multi_shot);
-
-static inline bool kasan_report_enabled(void)
-{
-	if (current->kasan_depth)
-		return false;
-	if (test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags))
-		return true;
-	return !test_and_set_bit(KASAN_BIT_REPORTED, &kasan_flags);
+	end_report(&flags);
 }
 
 void kasan_report(unsigned long addr, size_t size,
 		bool is_write, unsigned long ip)
 {
 	struct kasan_access_info info;
+	void *tagged_addr;
+	void *untagged_addr;
+	unsigned long flags;
 
-	if (likely(!kasan_report_enabled()))
+	if (likely(!report_enabled()))
 		return;
 
 	disable_trace_on_warning();
 
-	info.access_addr = (void *)addr;
-	info.first_bad_addr = (void *)addr;
+	tagged_addr = (void *)addr;
+	untagged_addr = reset_tag(tagged_addr);
+
+	info.access_addr = tagged_addr;
+	if (addr_has_shadow(untagged_addr))
+		info.first_bad_addr = find_first_bad_addr(tagged_addr, size);
+	else
+		info.first_bad_addr = untagged_addr;
 	info.access_size = size;
 	info.is_write = is_write;
 	info.ip = ip;
 
-	kasan_report_error(&info);
-}
+	start_report(&flags);
 
+	print_error_description(&info);
+	if (addr_has_shadow(untagged_addr))
+		print_tags(get_tag(tagged_addr), info.first_bad_addr);
+	pr_err("\n");
 
-#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);
+	if (addr_has_shadow(untagged_addr)) {
+		print_address_description(untagged_addr);
+		pr_err("\n");
+		print_shadow_for_address(info.first_bad_addr);
+	} else {
+		dump_stack();
+	}
 
-void __asan_report_store_n_noabort(unsigned long addr, size_t size)
-{
-	kasan_report(addr, size, true, _RET_IP_);
+	end_report(&flags);
 }
-EXPORT_SYMBOL(__asan_report_store_n_noabort);