[PATCH v11 16/24] kasan: split out generic_report.c from report.c

Andrey Konovalov
2018-11-19T17:27:27Z

This patch moves generic KASAN specific error reporting routines to
generic_report.c without any functional changes, leaving common error
reporting code in report.c to be later reused by tag-based KASAN.

Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
mm/kasan/Makefile | 4 +-
mm/kasan/generic_report.c | 158 +++++++++++++++++++++++++
mm/kasan/kasan.h | 7 ++
mm/kasan/report.c | 234 +++++++++-----------------------------
mm/kasan/tags_report.c | 39 +++++++
5 files changed, 257 insertions(+), 185 deletions(-)
create mode 100644 mm/kasan/generic_report.c
create mode 100644 mm/kasan/tags_report.c

diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile
index 68ba1822f003..0a14fcff70ed 100644
--- a/mm/kasan/Makefile
+++ b/mm/kasan/Makefile
@@ -14,5 +14,5 @@ CFLAGS_generic.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector)
CFLAGS_tags.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector)

obj-$(CONFIG_KASAN) := common.o init.o report.o
-obj-$(CONFIG_KASAN_GENERIC) += generic.o quarantine.o
-obj-$(CONFIG_KASAN_SW_TAGS) += tags.o
+obj-$(CONFIG_KASAN_GENERIC) += generic.o generic_report.o quarantine.o
+obj-$(CONFIG_KASAN_SW_TAGS) += tags.o tags_report.o
diff --git a/mm/kasan/generic_report.c b/mm/kasan/generic_report.c
new file mode 100644
index 000000000000..5201d1770700
--- /dev/null
+++ b/mm/kasan/generic_report.c
@@ -0,0 +1,158 @@
+/*
+ * This file contains generic KASAN specific error reporting code.
+ *
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd.
+ * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
+ *
+ * Some code borrowed from https://github.com/xairy/kasan-prototype by
+ * Andrey Konovalov <andreyknvl@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/bitops.h>
+#include <linux/ftrace.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/printk.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/stackdepot.h>
+#include <linux/stacktrace.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/kasan.h>
+#include <linux/module.h>
+
+#include <asm/sections.h>
+
+#include "kasan.h"
+#include "../slab.h"
+
+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 const char *get_shadow_bug_type(struct kasan_access_info *info)
+{
+ 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;
+}
+
+static const char *get_wild_bug_type(struct kasan_access_info *info)
+{
+ 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;
+}
+
+const char *get_bug_type(struct kasan_access_info *info)
+{
+ if (addr_has_shadow(info->access_addr))
+ return get_shadow_bug_type(info);
+ return get_wild_bug_type(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);
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 6e42f46522c0..6e808dbc31e8 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -109,11 +109,18 @@ static inline const void *kasan_shadow_to_mem(const void *shadow_addr)
<< KASAN_SHADOW_SCALE_SHIFT);
}

+static inline bool addr_has_shadow(const void *addr)
+{
+ return (addr >= kasan_shadow_to_mem((void *)KASAN_SHADOW_START));
+}
+
void kasan_poison_shadow(const void *address, size_t size, u8 value);

void check_memory_region(unsigned long addr, size_t size, bool write,
unsigned long ret_ip);

+const char *get_bug_type(struct kasan_access_info *info);
+
void kasan_report(unsigned long addr, size_t size,
bool is_write, unsigned long ip);
void kasan_report_invalid_free(void *object, unsigned long ip);
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 5c169aa688fd..64a74f334c45 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -1,5 +1,5 @@
/*
- * 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>
@@ -39,103 +39,34 @@
#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)
+static void print_error_description(struct kasan_access_info *info,
+ const char *bug_type)
{
- const char *bug_type = get_bug_type(info);
-
pr_err("BUG: KASAN: %s in %pS\n",
bug_type, (void *)info->ip);
pr_err("%s of size %zu at addr %px by task %s/%d\n",
@@ -143,25 +74,9 @@ static void print_error_description(struct kasan_access_info *info)
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);
@@ -326,29 +257,38 @@ 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);
pr_err("\n");
print_address_description(object);
pr_err("\n");
print_shadow_for_address(object);
- kasan_end_report(&flags);
+ end_report(&flags);
}

static void kasan_report_error(struct kasan_access_info *info)
{
unsigned long flags;

- kasan_start_report(&flags);
+ start_report(&flags);

- print_error_description(info);
+ print_error_description(info, get_bug_type(info));
pr_err("\n");

- if (!addr_has_shadow(info)) {
+ if (!addr_has_shadow(info->access_addr)) {
dump_stack();
} else {
print_address_description((void *)info->access_addr);
@@ -356,41 +296,7 @@ static void kasan_report_error(struct kasan_access_info *info)
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,
@@ -398,7 +304,7 @@ void kasan_report(unsigned long addr, size_t size,
{
struct kasan_access_info info;

- if (likely(!kasan_report_enabled()))
+ if (likely(!report_enabled()))
return;

disable_trace_on_warning();
@@ -411,41 +317,3 @@ void kasan_report(unsigned long addr, size_t size,

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);
diff --git a/mm/kasan/tags_report.c b/mm/kasan/tags_report.c
new file mode 100644
index 000000000000..8af15e87d3bc
--- /dev/null
+++ b/mm/kasan/tags_report.c
@@ -0,0 +1,39 @@
+/*
+ * This file contains tag-based KASAN specific error reporting code.
+ *
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd.
+ * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
+ *
+ * Some code borrowed from https://github.com/xairy/kasan-prototype by
+ * Andrey Konovalov <andreyknvl@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/bitops.h>
+#include <linux/ftrace.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/printk.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/stackdepot.h>
+#include <linux/stacktrace.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/kasan.h>
+#include <linux/module.h>
+
+#include <asm/sections.h>
+
+#include "kasan.h"
+#include "../slab.h"
+
+const char *get_bug_type(struct kasan_access_info *info)
+{
+ return "invalid-access";
+}
--
2.19.1.1215.g8438c0b245-goog