1 files changed, 344 insertions, 0 deletions

diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
new file mode 100644
index 000000000000..ccb6207276e3
--- /dev/null
+++ b/mm/kasan/generic.c
@@ -0,0 +1,344 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file contains core generic KASAN 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.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#define DISABLE_BRANCH_PROFILING
+
+#include <linux/export.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/kasan.h>
+#include <linux/kernel.h>
+#include <linux/kmemleak.h>
+#include <linux/linkage.h>
+#include <linux/memblock.h>
+#include <linux/memory.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/printk.h>
+#include <linux/sched.h>
+#include <linux/sched/task_stack.h>
+#include <linux/slab.h>
+#include <linux/stacktrace.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/vmalloc.h>
+#include <linux/bug.h>
+
+#include "kasan.h"
+#include "../slab.h"
+
+/*
+ * All functions below always inlined so compiler could
+ * perform better optimizations in each of __asan_loadX/__assn_storeX
+ * depending on memory access size X.
+ */
+
+static __always_inline bool memory_is_poisoned_1(unsigned long addr)
+{
+        s8 shadow_value = *(s8 *)kasan_mem_to_shadow((void *)addr);
+
+        if (unlikely(shadow_value)) {
+                s8 last_accessible_byte = addr & KASAN_SHADOW_MASK;
+                return unlikely(last_accessible_byte >= shadow_value);
+        }
+
+        return false;
+}
+
+static __always_inline bool memory_is_poisoned_2_4_8(unsigned long addr,
+                                                unsigned long size)
+{
+        u8 *shadow_addr = (u8 *)kasan_mem_to_shadow((void *)addr);
+
+        /*
+         * Access crosses 8(shadow size)-byte boundary. Such access maps
+         * into 2 shadow bytes, so we need to check them both.
+         */
+        if (unlikely(((addr + size - 1) & KASAN_SHADOW_MASK) < size - 1))
+                return *shadow_addr || memory_is_poisoned_1(addr + size - 1);
+
+        return memory_is_poisoned_1(addr + size - 1);
+}
+
+static __always_inline bool memory_is_poisoned_16(unsigned long addr)
+{
+        u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
+
+        /* Unaligned 16-bytes access maps into 3 shadow bytes. */
+        if (unlikely(!IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE)))
+                return *shadow_addr || memory_is_poisoned_1(addr + 15);
+
+        return *shadow_addr;
+}
+
+static __always_inline unsigned long bytes_is_nonzero(const u8 *start,
+                                        size_t size)
+{
+        while (size) {
+                if (unlikely(*start))
+                        return (unsigned long)start;
+                start++;
+                size--;
+        }
+
+        return 0;
+}
+
+static __always_inline unsigned long memory_is_nonzero(const void *start,
+                                                const void *end)
+{
+        unsigned int words;
+        unsigned long ret;
+        unsigned int prefix = (unsigned long)start % 8;
+
+        if (end - start <= 16)
+                return bytes_is_nonzero(start, end - start);
+
+        if (prefix) {
+                prefix = 8 - prefix;
+                ret = bytes_is_nonzero(start, prefix);
+                if (unlikely(ret))
+                        return ret;
+                start += prefix;
+        }
+
+        words = (end - start) / 8;
+        while (words) {
+                if (unlikely(*(u64 *)start))
+                        return bytes_is_nonzero(start, 8);
+                start += 8;
+                words--;
+        }
+
+        return bytes_is_nonzero(start, (end - start) % 8);
+}
+
+static __always_inline bool memory_is_poisoned_n(unsigned long addr,
+                                                size_t size)
+{
+        unsigned long ret;
+
+        ret = memory_is_nonzero(kasan_mem_to_shadow((void *)addr),
+                        kasan_mem_to_shadow((void *)addr + size - 1) + 1);
+
+        if (unlikely(ret)) {
+                unsigned long last_byte = addr + size - 1;
+                s8 *last_shadow = (s8 *)kasan_mem_to_shadow((void *)last_byte);
+
+                if (unlikely(ret != (unsigned long)last_shadow ||
+                        ((long)(last_byte & KASAN_SHADOW_MASK) >= *last_shadow)))
+                        return true;
+        }
+        return false;
+}
+
+static __always_inline bool memory_is_poisoned(unsigned long addr, size_t size)
+{
+        if (__builtin_constant_p(size)) {
+                switch (size) {
+                case 1:
+                        return memory_is_poisoned_1(addr);
+                case 2:
+                case 4:
+                case 8:
+                        return memory_is_poisoned_2_4_8(addr, size);
+                case 16:
+                        return memory_is_poisoned_16(addr);
+                default:
+                        BUILD_BUG();
+                }
+        }
+
+        return memory_is_poisoned_n(addr, size);
+}
+
+static __always_inline void check_memory_region_inline(unsigned long addr,
+                                                size_t size, bool write,
+                                                unsigned long ret_ip)
+{
+        if (unlikely(size == 0))
+                return;
+
+        if (unlikely((void *)addr <
+                kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
+                kasan_report(addr, size, write, ret_ip);
+                return;
+        }
+
+        if (likely(!memory_is_poisoned(addr, size)))
+                return;
+
+        kasan_report(addr, size, write, ret_ip);
+}
+
+void check_memory_region(unsigned long addr, size_t size, bool write,
+                                unsigned long ret_ip)
+{
+        check_memory_region_inline(addr, size, write, ret_ip);
+}
+
+void kasan_cache_shrink(struct kmem_cache *cache)
+{
+        quarantine_remove_cache(cache);
+}
+
+void kasan_cache_shutdown(struct kmem_cache *cache)
+{
+        if (!__kmem_cache_empty(cache))
+                quarantine_remove_cache(cache);
+}
+
+static void register_global(struct kasan_global *global)
+{
+        size_t aligned_size = round_up(global->size, KASAN_SHADOW_SCALE_SIZE);
+
+        kasan_unpoison_shadow(global->beg, global->size);
+
+        kasan_poison_shadow(global->beg + aligned_size,
+                global->size_with_redzone - aligned_size,
+                KASAN_GLOBAL_REDZONE);
+}
+
+void __asan_register_globals(struct kasan_global *globals, size_t size)
+{
+        int i;
+
+        for (i = 0; i < size; i++)
+                register_global(&globals[i]);
+}
+EXPORT_SYMBOL(__asan_register_globals);
+
+void __asan_unregister_globals(struct kasan_global *globals, size_t size)
+{
+}
+EXPORT_SYMBOL(__asan_unregister_globals);
+
+#define DEFINE_ASAN_LOAD_STORE(size)                                    \
+        void __asan_load##size(unsigned long addr)                      \
+        {                                                               \
+                check_memory_region_inline(addr, size, false, _RET_IP_);\
+        }                                                               \
+        EXPORT_SYMBOL(__asan_load##size);                               \
+        __alias(__asan_load##size)                                      \
+        void __asan_load##size##_noabort(unsigned long);                \
+        EXPORT_SYMBOL(__asan_load##size##_noabort);                     \
+        void __asan_store##size(unsigned long addr)                     \
+        {                                                               \
+                check_memory_region_inline(addr, size, true, _RET_IP_); \
+        }                                                               \
+        EXPORT_SYMBOL(__asan_store##size);                              \
+        __alias(__asan_store##size)                                     \
+        void __asan_store##size##_noabort(unsigned long);               \
+        EXPORT_SYMBOL(__asan_store##size##_noabort)
+
+DEFINE_ASAN_LOAD_STORE(1);
+DEFINE_ASAN_LOAD_STORE(2);
+DEFINE_ASAN_LOAD_STORE(4);
+DEFINE_ASAN_LOAD_STORE(8);
+DEFINE_ASAN_LOAD_STORE(16);
+
+void __asan_loadN(unsigned long addr, size_t size)
+{
+        check_memory_region(addr, size, false, _RET_IP_);
+}
+EXPORT_SYMBOL(__asan_loadN);
+
+__alias(__asan_loadN)
+void __asan_loadN_noabort(unsigned long, size_t);
+EXPORT_SYMBOL(__asan_loadN_noabort);
+
+void __asan_storeN(unsigned long addr, size_t size)
+{
+        check_memory_region(addr, size, true, _RET_IP_);
+}
+EXPORT_SYMBOL(__asan_storeN);
+
+__alias(__asan_storeN)
+void __asan_storeN_noabort(unsigned long, size_t);
+EXPORT_SYMBOL(__asan_storeN_noabort);
+
+/* to shut up compiler complaints */
+void __asan_handle_no_return(void) {}
+EXPORT_SYMBOL(__asan_handle_no_return);
+
+/* Emitted by compiler to poison large objects when they go out of scope. */
+void __asan_poison_stack_memory(const void *addr, size_t size)
+{
+        /*
+         * Addr is KASAN_SHADOW_SCALE_SIZE-aligned and the object is surrounded
+         * by redzones, so we simply round up size to simplify logic.
+         */
+        kasan_poison_shadow(addr, round_up(size, KASAN_SHADOW_SCALE_SIZE),
+                            KASAN_USE_AFTER_SCOPE);
+}
+EXPORT_SYMBOL(__asan_poison_stack_memory);
+
+/* Emitted by compiler to unpoison large objects when they go into scope. */
+void __asan_unpoison_stack_memory(const void *addr, size_t size)
+{
+        kasan_unpoison_shadow(addr, size);
+}
+EXPORT_SYMBOL(__asan_unpoison_stack_memory);
+
+/* Emitted by compiler to poison alloca()ed objects. */
+void __asan_alloca_poison(unsigned long addr, size_t size)
+{
+        size_t rounded_up_size = round_up(size, KASAN_SHADOW_SCALE_SIZE);
+        size_t padding_size = round_up(size, KASAN_ALLOCA_REDZONE_SIZE) -
+                        rounded_up_size;
+        size_t rounded_down_size = round_down(size, KASAN_SHADOW_SCALE_SIZE);
+
+        const void *left_redzone = (const void *)(addr -
+                        KASAN_ALLOCA_REDZONE_SIZE);
+        const void *right_redzone = (const void *)(addr + rounded_up_size);
+
+        WARN_ON(!IS_ALIGNED(addr, KASAN_ALLOCA_REDZONE_SIZE));
+
+        kasan_unpoison_shadow((const void *)(addr + rounded_down_size),
+                              size - rounded_down_size);
+        kasan_poison_shadow(left_redzone, KASAN_ALLOCA_REDZONE_SIZE,
+                        KASAN_ALLOCA_LEFT);
+        kasan_poison_shadow(right_redzone,
+                        padding_size + KASAN_ALLOCA_REDZONE_SIZE,
+                        KASAN_ALLOCA_RIGHT);
+}
+EXPORT_SYMBOL(__asan_alloca_poison);
+
+/* Emitted by compiler to unpoison alloca()ed areas when the stack unwinds. */
+void __asan_allocas_unpoison(const void *stack_top, const void *stack_bottom)
+{
+        if (unlikely(!stack_top || stack_top > stack_bottom))
+                return;
+
+        kasan_unpoison_shadow(stack_top, stack_bottom - stack_top);
+}
+EXPORT_SYMBOL(__asan_allocas_unpoison);
+
+/* Emitted by the compiler to [un]poison local variables. */
+#define DEFINE_ASAN_SET_SHADOW(byte) \
+        void __asan_set_shadow_##byte(const void *addr, size_t size)    \
+        {                                                               \
+                __memset((void *)addr, 0x##byte, size);                 \
+        }                                                               \
+        EXPORT_SYMBOL(__asan_set_shadow_##byte)
+
+DEFINE_ASAN_SET_SHADOW(00);
+DEFINE_ASAN_SET_SHADOW(f1);
+DEFINE_ASAN_SET_SHADOW(f2);
+DEFINE_ASAN_SET_SHADOW(f3);
+DEFINE_ASAN_SET_SHADOW(f5);
+DEFINE_ASAN_SET_SHADOW(f8);