kasan: add hardware tag-based mode for arm64

Don't mention "GNU General Public License version 2" text explicitly, as it's already covered by the SPDX-License-Identifier.

Signed-off-by Andrey Konovalov <[email protected]>

Signed-off-by Vincenzo Frascino <[email protected]>

Reviewed-by Marco Elver <[email protected]>

---
Change-Id: If0a2690042a2aa0fca70cea601ae9aabe72fa233

---
 mm/kasan/common.c         |  5 -----
 mm/kasan/generic.c        |  5 -----
 mm/kasan/generic_report.c |  5 -----
 mm/kasan/init.c           |  5 -----
 mm/kasan/quarantine.c     | 10 ----------
 mm/kasan/report.c         |  5 -----
 mm/kasan/tags.c           |  5 -----
 mm/kasan/tags_report.c    |  5 -----
 8 files changed, 45 deletions(-)

mm/kasan/common.c +0 -5

index 950fd372a07e..33d863f55db1 100644
@@ -7,11 +7,6 @@
  *
  * Some code borrowed from https://github.com/xairy/kasan-prototype by
  *        Andrey Konovalov <[email protected]>
- *
- * 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/export.h>

mm/kasan/generic.c +0 -5

index 248264b9cb76..37ccfadd3263 100644
@@ -7,11 +7,6 @@
  *
  * Some code borrowed from https://github.com/xairy/kasan-prototype by
  *        Andrey Konovalov <[email protected]>
- *
- * 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

mm/kasan/generic_report.c +0 -5

index a38c7a9e192a..6bb3f66992df 100644
@@ -7,11 +7,6 @@
  *
  * Some code borrowed from https://github.com/xairy/kasan-prototype by
  *        Andrey Konovalov <[email protected]>
- *
- * 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>

mm/kasan/init.c +0 -5

index fe6be0be1f76..9ce8cc5b8621 100644
@@ -4,11 +4,6 @@
  *
  * Copyright (c) 2015 Samsung Electronics Co., Ltd.
  * Author: Andrey Ryabinin <[email protected]>
- *
- * 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/memblock.h>

mm/kasan/quarantine.c +0 -10

index 4c5375810449..580ff5610fc1 100644
@@ -6,16 +6,6 @@
  * Copyright (C) 2016 Google, Inc.
  *
  * Based on code by Dmitry Chernenkov.
- *
- * 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.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
  */
 
 #include <linux/gfp.h>

mm/kasan/report.c +0 -5

index 00a53f1355ae..d500923abc8b 100644
@@ -7,11 +7,6 @@
  *
  * Some code borrowed from https://github.com/xairy/kasan-prototype by
  *        Andrey Konovalov <[email protected]>
- *
- * 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>

mm/kasan/tags.c +0 -5

index e02a36a51f42..5c8b08a25715 100644
@@ -4,11 +4,6 @@
  *
  * Copyright (c) 2018 Google, Inc.
  * Author: Andrey Konovalov <[email protected]>
- *
- * 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

mm/kasan/tags_report.c +0 -6

index bee43717d6f0..5f183501b871 100644
@@ -7,11 +7,6 @@
  *
  * Some code borrowed from https://github.com/xairy/kasan-prototype by
  *        Andrey Konovalov <[email protected]>
- *
- * 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>
--

2.29.2.222.g5d2a92d10f8-goog

Currently only generic KASAN mode supports vmalloc, reflect that in the config.

Signed-off-by Andrey Konovalov <[email protected]>

Signed-off-by Vincenzo Frascino <[email protected]>

Reviewed-by Marco Elver <[email protected]>

---
Change-Id: I1889e5b3bed28cc5d607802fb6ae43ba461c0dc1

---
 lib/Kconfig.kasan | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

lib/Kconfig.kasan +1 -2

index 542a9c18398e..8f0742a0f23e 100644
@@ -155,7 +155,7 @@ config KASAN_SW_TAGS_IDENTIFY
 
 config KASAN_VMALLOC
        bool "Back mappings in vmalloc space with real shadow memory"
-       depends on HAVE_ARCH_KASAN_VMALLOC
+       depends on KASAN_GENERIC && HAVE_ARCH_KASAN_VMALLOC
        help
          By default, the shadow region for vmalloc space is the read-only
          zero page. This means that KASAN cannot detect errors involving
--

2.29.2.222.g5d2a92d10f8-goog

This is a preparatory commit for the upcoming addition of a new hardware tag-based (MTE-based) KASAN mode.

Group all vmalloc-related function declarations in include/linux/kasan.h, and their implementations in mm/kasan/common.c.

No functional changes.

Signed-off-by Andrey Konovalov <[email protected]>

Signed-off-by Vincenzo Frascino <[email protected]>

Reviewed-by Marco Elver <[email protected]>

---
Change-Id: Ie20b6c689203cd6de4fd7f2c465ec081c00c5f15

---
 include/linux/kasan.h | 41 +++++++++++++----------
 mm/kasan/common.c     | 78 ++++++++++++++++++++++---------------------
 2 files changed, 63 insertions(+), 56 deletions(-)

include/linux/kasan.h +23 -18

index 30d343b4a40a..59538e795df4 100644
@@ -75,19 +75,6 @@ struct kasan_cache {
        int free_meta_offset;
 };
 
-/*
- * These functions provide a special case to support backing module
- * allocations with real shadow memory. With KASAN vmalloc, the special
- * case is unnecessary, as the work is handled in the generic case.
- */
-#ifndef CONFIG_KASAN_VMALLOC
-int kasan_module_alloc(void *addr, size_t size);
-void kasan_free_shadow(const struct vm_struct *vm);
-#else
-static inline int kasan_module_alloc(void *addr, size_t size) { return 0; }
-static inline void kasan_free_shadow(const struct vm_struct *vm) {}
-#endif
-
 int kasan_add_zero_shadow(void *start, unsigned long size);
 void kasan_remove_zero_shadow(void *start, unsigned long size);
 

@@ -156,9 +143,6 @@ static inline bool kasan_slab_free(struct kmem_cache *s, void *object,
        return false;
 }
 
-static inline int kasan_module_alloc(void *addr, size_t size) { return 0; }
-static inline void kasan_free_shadow(const struct vm_struct *vm) {}
-
 static inline int kasan_add_zero_shadow(void *start, unsigned long size)
 {
        return 0;

@@ -211,13 +195,16 @@ static inline void *kasan_reset_tag(const void *addr)
 #endif /* CONFIG_KASAN_SW_TAGS */
 
 #ifdef CONFIG_KASAN_VMALLOC
+
 int kasan_populate_vmalloc(unsigned long addr, unsigned long size);
 void kasan_poison_vmalloc(const void *start, unsigned long size);
 void kasan_unpoison_vmalloc(const void *start, unsigned long size);
 void kasan_release_vmalloc(unsigned long start, unsigned long end,
                           unsigned long free_region_start,
                           unsigned long free_region_end);
-#else
+
+#else /* CONFIG_KASAN_VMALLOC */
+
 static inline int kasan_populate_vmalloc(unsigned long start,
                                        unsigned long size)
 {

@@ -232,7 +219,25 @@ static inline void kasan_release_vmalloc(unsigned long start,
                                         unsigned long end,
                                         unsigned long free_region_start,
                                         unsigned long free_region_end) {}
-#endif
+
+#endif /* CONFIG_KASAN_VMALLOC */
+
+#if defined(CONFIG_KASAN) && !defined(CONFIG_KASAN_VMALLOC)
+
+/*
+ * These functions provide a special case to support backing module
+ * allocations with real shadow memory. With KASAN vmalloc, the special
+ * case is unnecessary, as the work is handled in the generic case.
+ */
+int kasan_module_alloc(void *addr, size_t size);
+void kasan_free_shadow(const struct vm_struct *vm);
+
+#else /* CONFIG_KASAN && !CONFIG_KASAN_VMALLOC */
+
+static inline int kasan_module_alloc(void *addr, size_t size) { return 0; }
+static inline void kasan_free_shadow(const struct vm_struct *vm) {}
+
+#endif /* CONFIG_KASAN && !CONFIG_KASAN_VMALLOC */
 
 #ifdef CONFIG_KASAN_INLINE
 void kasan_non_canonical_hook(unsigned long addr);

mm/kasan/common.c +40 -39

index 33d863f55db1..89e5ef9417a7 100644
@@ -536,44 +536,6 @@ void kasan_kfree_large(void *ptr, unsigned long ip)
        /* The object will be poisoned by page_alloc. */
 }
 
-#ifndef CONFIG_KASAN_VMALLOC
-int kasan_module_alloc(void *addr, size_t size)
-{
-       void *ret;
-       size_t scaled_size;
-       size_t shadow_size;
-       unsigned long shadow_start;
-
-       shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
-       scaled_size = (size + KASAN_SHADOW_MASK) >> KASAN_SHADOW_SCALE_SHIFT;
-       shadow_size = round_up(scaled_size, PAGE_SIZE);
-
-       if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
-               return -EINVAL;
-
-       ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
-                       shadow_start + shadow_size,
-                       GFP_KERNEL,
-                       PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
-                       __builtin_return_address(0));
-
-       if (ret) {
-               __memset(ret, KASAN_SHADOW_INIT, shadow_size);
-               find_vm_area(addr)->flags |= VM_KASAN;
-               kmemleak_ignore(ret);
-               return 0;
-       }
-
-       return -ENOMEM;
-}
-
-void kasan_free_shadow(const struct vm_struct *vm)
-{
-       if (vm->flags & VM_KASAN)
-               vfree(kasan_mem_to_shadow(vm->addr));
-}
-#endif
-
 #ifdef CONFIG_MEMORY_HOTPLUG
 static bool shadow_mapped(unsigned long addr)
 {

@@ -685,6 +647,7 @@ core_initcall(kasan_memhotplug_init);
 #endif
 
 #ifdef CONFIG_KASAN_VMALLOC
+
 static int kasan_populate_vmalloc_pte(pte_t *ptep, unsigned long addr,
                                      void *unused)
 {

@@ -923,4 +886,43 @@ void kasan_release_vmalloc(unsigned long start, unsigned long end,
                                       (unsigned long)shadow_end);
        }
 }
+
+#else /* CONFIG_KASAN_VMALLOC */
+
+int kasan_module_alloc(void *addr, size_t size)
+{
+       void *ret;
+       size_t scaled_size;
+       size_t shadow_size;
+       unsigned long shadow_start;
+
+       shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
+       scaled_size = (size + KASAN_SHADOW_MASK) >> KASAN_SHADOW_SCALE_SHIFT;
+       shadow_size = round_up(scaled_size, PAGE_SIZE);
+
+       if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
+               return -EINVAL;
+
+       ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
+                       shadow_start + shadow_size,
+                       GFP_KERNEL,
+                       PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
+                       __builtin_return_address(0));
+
+       if (ret) {
+               __memset(ret, KASAN_SHADOW_INIT, shadow_size);
+               find_vm_area(addr)->flags |= VM_KASAN;
+               kmemleak_ignore(ret);
+               return 0;
+       }
+
+       return -ENOMEM;
+}
+
+void kasan_free_shadow(const struct vm_struct *vm)
+{
+       if (vm->flags & VM_KASAN)
+               vfree(kasan_mem_to_shadow(vm->addr));
+}
+
 #endif
--

2.29.2.222.g5d2a92d10f8-goog

This is a preparatory commit for the upcoming addition of a new hardware tag-based (MTE-based) KASAN mode.

Group shadow-related KASAN function declarations and only define them for the two existing software modes.

No functional changes for software modes.

Signed-off-by Andrey Konovalov <[email protected]>

Signed-off-by Vincenzo Frascino <[email protected]>

Reviewed-by Marco Elver <[email protected]>

---
Change-Id: I864be75a88b91b443c55e9c2042865e15703e164

---
 include/linux/kasan.h | 47 ++++++++++++++++++++++++++++---------------
 1 file changed, 31 insertions(+), 16 deletions(-)

include/linux/kasan.h +31 -17

index 59538e795df4..26f2ab92e7ca 100644
@@ -11,7 +11,6 @@ struct task_struct;
 
 #ifdef CONFIG_KASAN
 
-#include <linux/pgtable.h>
 #include <asm/kasan.h>
 
 /* kasan_data struct is used in KUnit tests for KASAN expected failures */

@@ -20,6 +19,20 @@ struct kunit_kasan_expectation {
        bool report_found;
 };
 
+#endif
+
+#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
+
+#include <linux/pgtable.h>
+
+/* Software KASAN implementations use shadow memory. */
+
+#ifdef CONFIG_KASAN_SW_TAGS
+#define KASAN_SHADOW_INIT 0xFF
+#else
+#define KASAN_SHADOW_INIT 0
+#endif
+
 extern unsigned char kasan_early_shadow_page[PAGE_SIZE];
 extern pte_t kasan_early_shadow_pte[PTRS_PER_PTE];
 extern pmd_t kasan_early_shadow_pmd[PTRS_PER_PMD];

@@ -35,6 +48,23 @@ static inline void *kasan_mem_to_shadow(const void *addr)
                + KASAN_SHADOW_OFFSET;
 }
 
+int kasan_add_zero_shadow(void *start, unsigned long size);
+void kasan_remove_zero_shadow(void *start, unsigned long size);
+
+#else /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
+
+static inline int kasan_add_zero_shadow(void *start, unsigned long size)
+{
+       return 0;
+}
+static inline void kasan_remove_zero_shadow(void *start,
+                                       unsigned long size)
+{}
+
+#endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
+
+#ifdef CONFIG_KASAN
+
 /* Enable reporting bugs after kasan_disable_current() */
 extern void kasan_enable_current(void);
 

@@ -75,9 +105,6 @@ struct kasan_cache {
        int free_meta_offset;
 };
 
-int kasan_add_zero_shadow(void *start, unsigned long size);
-void kasan_remove_zero_shadow(void *start, unsigned long size);
-
 size_t __ksize(const void *);
 static inline void kasan_unpoison_slab(const void *ptr)
 {

@@ -143,14 +170,6 @@ static inline bool kasan_slab_free(struct kmem_cache *s, void *object,
        return false;
 }
 
-static inline int kasan_add_zero_shadow(void *start, unsigned long size)
-{
-       return 0;
-}
-static inline void kasan_remove_zero_shadow(void *start,
-                                       unsigned long size)
-{}
-
 static inline void kasan_unpoison_slab(const void *ptr) { }
 static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; }
 

@@ -158,8 +177,6 @@ static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; }
 
 #ifdef CONFIG_KASAN_GENERIC
 
-#define KASAN_SHADOW_INIT 0
-
 void kasan_cache_shrink(struct kmem_cache *cache);
 void kasan_cache_shutdown(struct kmem_cache *cache);
 void kasan_record_aux_stack(void *ptr);

@@ -174,8 +191,6 @@ static inline void kasan_record_aux_stack(void *ptr) {}
 
 #ifdef CONFIG_KASAN_SW_TAGS
 
-#define KASAN_SHADOW_INIT 0xFF
-
 void kasan_init_tags(void);
 
 void *kasan_reset_tag(const void *addr);
--

2.29.2.222.g5d2a92d10f8-goog

This is a preparatory commit for the upcoming addition of a new hardware tag-based (MTE-based) KASAN mode.

The new mode won't be using shadow memory, but will reuse the same functions. Rename kasan_unpoison_shadow to kasan_unpoison_memory, and kasan_poison_shadow to kasan_poison_memory.

No functional changes.

Signed-off-by Andrey Konovalov <[email protected]>

Signed-off-by Vincenzo Frascino <[email protected]>

Reviewed-by Marco Elver <[email protected]>

---
Change-Id: Ia359f32815242c4704e49a5f1639ca2d2f8cba69

---
 include/linux/kasan.h |  6 +++---
 kernel/fork.c         |  4 ++--
 mm/kasan/common.c     | 38 +++++++++++++++++++-------------------
 mm/kasan/generic.c    | 12 ++++++------
 mm/kasan/kasan.h      |  2 +-
 mm/kasan/tags.c       |  2 +-
 mm/slab_common.c      |  2 +-
 7 files changed, 33 insertions(+), 33 deletions(-)

include/linux/kasan.h +3 -3

index 26f2ab92e7ca..f6435b9f889c 100644
@@ -71,7 +71,7 @@ extern void kasan_enable_current(void);
 /* Disable reporting bugs for current task */
 extern void kasan_disable_current(void);
 
-void kasan_unpoison_shadow(const void *address, size_t size);
+void kasan_unpoison_memory(const void *address, size_t size);
 
 void kasan_unpoison_task_stack(struct task_struct *task);
 

@@ -108,7 +108,7 @@ struct kasan_cache {
 size_t __ksize(const void *);
 static inline void kasan_unpoison_slab(const void *ptr)
 {
-       kasan_unpoison_shadow(ptr, __ksize(ptr));
+       kasan_unpoison_memory(ptr, __ksize(ptr));
 }
 size_t kasan_metadata_size(struct kmem_cache *cache);
 

@@ -117,7 +117,7 @@ void kasan_restore_multi_shot(bool enabled);
 
 #else /* CONFIG_KASAN */
 
-static inline void kasan_unpoison_shadow(const void *address, size_t size) {}
+static inline void kasan_unpoison_memory(const void *address, size_t size) {}
 
 static inline void kasan_unpoison_task_stack(struct task_struct *task) {}
 

kernel/fork.c +2 -2

index 6d266388d380..1c905e4290ab 100644
@@ -225,8 +225,8 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
                if (!s)
                        continue;
 
-               /* Clear the KASAN shadow of the stack. */
-               kasan_unpoison_shadow(s->addr, THREAD_SIZE);
+               /* Mark stack accessible for KASAN. */
+               kasan_unpoison_memory(s->addr, THREAD_SIZE);
 
                /* Clear stale pointers from reused stack. */
                memset(s->addr, 0, THREAD_SIZE);

mm/kasan/common.c +19 -19

index 89e5ef9417a7..a4b73fa0dd7e 100644
@@ -108,7 +108,7 @@ void *memcpy(void *dest, const void *src, size_t len)
  * Poisons the shadow memory for 'size' bytes starting from 'addr'.
  * Memory addresses should be aligned to KASAN_SHADOW_SCALE_SIZE.
  */
-void kasan_poison_shadow(const void *address, size_t size, u8 value)
+void kasan_poison_memory(const void *address, size_t size, u8 value)
 {
        void *shadow_start, *shadow_end;
 

@@ -125,7 +125,7 @@ void kasan_poison_shadow(const void *address, size_t size, u8 value)
        __memset(shadow_start, value, shadow_end - shadow_start);
 }
 
-void kasan_unpoison_shadow(const void *address, size_t size)
+void kasan_unpoison_memory(const void *address, size_t size)
 {
        u8 tag = get_tag(address);
 

@@ -136,7 +136,7 @@ void kasan_unpoison_shadow(const void *address, size_t size)
         */
        address = reset_tag(address);
 
-       kasan_poison_shadow(address, size, tag);
+       kasan_poison_memory(address, size, tag);
 
        if (size & KASAN_SHADOW_MASK) {
                u8 *shadow = (u8 *)kasan_mem_to_shadow(address + size);

@@ -153,7 +153,7 @@ static void __kasan_unpoison_stack(struct task_struct *task, const void *sp)
        void *base = task_stack_page(task);
        size_t size = sp - base;
 
-       kasan_unpoison_shadow(base, size);
+       kasan_unpoison_memory(base, size);
 }
 
 /* Unpoison the entire stack for a task. */

@@ -172,7 +172,7 @@ asmlinkage void kasan_unpoison_task_stack_below(const void *watermark)
         */
        void *base = (void *)((unsigned long)watermark & ~(THREAD_SIZE - 1));
 
-       kasan_unpoison_shadow(base, watermark - base);
+       kasan_unpoison_memory(base, watermark - base);
 }
 
 void kasan_alloc_pages(struct page *page, unsigned int order)

@@ -186,13 +186,13 @@ void kasan_alloc_pages(struct page *page, unsigned int order)
        tag = random_tag();
        for (i = 0; i < (1 << order); i++)
                page_kasan_tag_set(page + i, tag);
-       kasan_unpoison_shadow(page_address(page), PAGE_SIZE << order);
+       kasan_unpoison_memory(page_address(page), PAGE_SIZE << order);
 }
 
 void kasan_free_pages(struct page *page, unsigned int order)
 {
        if (likely(!PageHighMem(page)))
-               kasan_poison_shadow(page_address(page),
+               kasan_poison_memory(page_address(page),
                                PAGE_SIZE << order,
                                KASAN_FREE_PAGE);
 }

@@ -284,18 +284,18 @@ void kasan_poison_slab(struct page *page)
 
        for (i = 0; i < compound_nr(page); i++)
                page_kasan_tag_reset(page + i);
-       kasan_poison_shadow(page_address(page), page_size(page),
+       kasan_poison_memory(page_address(page), page_size(page),
                        KASAN_KMALLOC_REDZONE);
 }
 
 void kasan_unpoison_object_data(struct kmem_cache *cache, void *object)
 {
-       kasan_unpoison_shadow(object, cache->object_size);
+       kasan_unpoison_memory(object, cache->object_size);
 }
 
 void kasan_poison_object_data(struct kmem_cache *cache, void *object)
 {
-       kasan_poison_shadow(object,
+       kasan_poison_memory(object,
                        round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE),
                        KASAN_KMALLOC_REDZONE);
 }

@@ -408,7 +408,7 @@ static bool __kasan_slab_free(struct kmem_cache *cache, void *object,
        }
 
        rounded_up_size = round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE);
-       kasan_poison_shadow(object, rounded_up_size, KASAN_KMALLOC_FREE);
+       kasan_poison_memory(object, rounded_up_size, KASAN_KMALLOC_FREE);
 
        if ((IS_ENABLED(CONFIG_KASAN_GENERIC) && !quarantine) ||
                        unlikely(!(cache->flags & SLAB_KASAN)))

@@ -448,8 +448,8 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object,
                tag = assign_tag(cache, object, false, keep_tag);
 
        /* Tag is ignored in set_tag without CONFIG_KASAN_SW_TAGS */
-       kasan_unpoison_shadow(set_tag(object, tag), size);
-       kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
+       kasan_unpoison_memory(set_tag(object, tag), size);
+       kasan_poison_memory((void *)redzone_start, redzone_end - redzone_start,
                KASAN_KMALLOC_REDZONE);
 
        if (cache->flags & SLAB_KASAN)

@@ -489,8 +489,8 @@ void * __must_check kasan_kmalloc_large(const void *ptr, size_t size,
                                KASAN_SHADOW_SCALE_SIZE);
        redzone_end = (unsigned long)ptr + page_size(page);
 
-       kasan_unpoison_shadow(ptr, size);
-       kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
+       kasan_unpoison_memory(ptr, size);
+       kasan_poison_memory((void *)redzone_start, redzone_end - redzone_start,
                KASAN_PAGE_REDZONE);
 
        return (void *)ptr;

@@ -523,7 +523,7 @@ void kasan_poison_kfree(void *ptr, unsigned long ip)
                        kasan_report_invalid_free(ptr, ip);
                        return;
                }
-               kasan_poison_shadow(ptr, page_size(page), KASAN_FREE_PAGE);
+               kasan_poison_memory(ptr, page_size(page), KASAN_FREE_PAGE);
        } else {
                __kasan_slab_free(page->slab_cache, ptr, ip, false);
        }

@@ -709,7 +709,7 @@ int kasan_populate_vmalloc(unsigned long addr, unsigned long size)
         * // vmalloc() allocates memory
         * // let a = area->addr
         * // we reach kasan_populate_vmalloc
-        * // and call kasan_unpoison_shadow:
+        * // and call kasan_unpoison_memory:
         * STORE shadow(a), unpoison_val
         * ...
         * STORE shadow(a+99), unpoison_val     x = LOAD p

@@ -744,7 +744,7 @@ void kasan_poison_vmalloc(const void *start, unsigned long size)
                return;
 
        size = round_up(size, KASAN_SHADOW_SCALE_SIZE);
-       kasan_poison_shadow(start, size, KASAN_VMALLOC_INVALID);
+       kasan_poison_memory(start, size, KASAN_VMALLOC_INVALID);
 }
 
 void kasan_unpoison_vmalloc(const void *start, unsigned long size)

@@ -752,7 +752,7 @@ void kasan_unpoison_vmalloc(const void *start, unsigned long size)
        if (!is_vmalloc_or_module_addr(start))
                return;
 
-       kasan_unpoison_shadow(start, size);
+       kasan_unpoison_memory(start, size);
 }
 
 static int kasan_depopulate_vmalloc_pte(pte_t *ptep, unsigned long addr,

mm/kasan/generic.c +6 -6

index 37ccfadd3263..7006157c674b 100644
@@ -202,9 +202,9 @@ 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_unpoison_memory(global->beg, global->size);
 
-       kasan_poison_shadow(global->beg + aligned_size,
+       kasan_poison_memory(global->beg + aligned_size,
                global->size_with_redzone - aligned_size,
                KASAN_GLOBAL_REDZONE);
 }

@@ -285,11 +285,11 @@ void __asan_alloca_poison(unsigned long addr, size_t size)
 
        WARN_ON(!IS_ALIGNED(addr, KASAN_ALLOCA_REDZONE_SIZE));
 
-       kasan_unpoison_shadow((const void *)(addr + rounded_down_size),
+       kasan_unpoison_memory((const void *)(addr + rounded_down_size),
                              size - rounded_down_size);
-       kasan_poison_shadow(left_redzone, KASAN_ALLOCA_REDZONE_SIZE,
+       kasan_poison_memory(left_redzone, KASAN_ALLOCA_REDZONE_SIZE,
                        KASAN_ALLOCA_LEFT);
-       kasan_poison_shadow(right_redzone,
+       kasan_poison_memory(right_redzone,
                        padding_size + KASAN_ALLOCA_REDZONE_SIZE,
                        KASAN_ALLOCA_RIGHT);
 }

@@ -301,7 +301,7 @@ 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);
+       kasan_unpoison_memory(stack_top, stack_bottom - stack_top);
 }
 EXPORT_SYMBOL(__asan_allocas_unpoison);
 

mm/kasan/kasan.h +1 -1

index ac499456740f..03450d3b31f7 100644
@@ -150,7 +150,7 @@ 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 kasan_poison_memory(const void *address, size_t size, u8 value);
 
 /**
  * check_memory_region - Check memory region, and report if invalid access.

mm/kasan/tags.c +1 -1

index 5c8b08a25715..4bdd7dbd6647 100644
@@ -153,7 +153,7 @@ EXPORT_SYMBOL(__hwasan_storeN_noabort);
 
 void __hwasan_tag_memory(unsigned long addr, u8 tag, unsigned long size)
 {
-       kasan_poison_shadow((void *)addr, size, tag);
+       kasan_poison_memory((void *)addr, size, tag);
 }
 EXPORT_SYMBOL(__hwasan_tag_memory);
 

mm/slab_common.c +1 -2

index f9ccd5dc13f3..53d0f8bb57ea 100644
@@ -1176,7 +1176,7 @@ size_t ksize(const void *objp)
         * We assume that ksize callers could use whole allocated area,
         * so we need to unpoison this area.
         */
-       kasan_unpoison_shadow(objp, size);
+       kasan_unpoison_memory(objp, size);
        return size;
 }
 EXPORT_SYMBOL(ksize);
--

2.29.2.222.g5d2a92d10f8-goog

This is a preparatory commit for the upcoming addition of a new hardware tag-based (MTE-based) KASAN mode.

The new mode won't be using shadow memory, but will still use the concept of memory granules. Each memory granule maps to a single metadata entry:
8 bytes per one shadow byte for generic mode, 16 bytes per one shadow byte for software tag-based mode, and 16 bytes per one allocation tag for hardware tag-based mode.

Rename KASAN_SHADOW_SCALE_SIZE to KASAN_GRANULE_SIZE, and KASAN_SHADOW_MASK to KASAN_GRANULE_MASK.

Also use MASK when used as a mask, otherwise use SIZE.

No functional changes.

Signed-off-by Andrey Konovalov <[email protected]>

Signed-off-by Vincenzo Frascino <[email protected]>

Reviewed-by Marco Elver <[email protected]>

---
Change-Id: Iac733e2248aa9d29f6fc425d8946ba07cca73ecf

---
 Documentation/dev-tools/kasan.rst |  2 +-
 lib/test_kasan.c                  |  2 +-
 lib/test_kasan_module.c           |  2 +-
 mm/kasan/common.c                 | 39 ++++++++++++++++---------------
 mm/kasan/generic.c                | 14 +++++------
 mm/kasan/generic_report.c         |  8 +++----
 mm/kasan/init.c                   |  8 +++----
 mm/kasan/kasan.h                  |  4 ++--
 mm/kasan/report.c                 | 10 ++++----
 mm/kasan/tags_report.c            |  2 +-
 10 files changed, 46 insertions(+), 45 deletions(-)

Documentation/dev-tools/kasan.rst +1 -1

index 2b68addaadcd..edca4be5e405 100644
@@ -264,7 +264,7 @@ Most mappings in vmalloc space are small, requiring less than a full
 page of shadow space. Allocating a full shadow page per mapping would
 therefore be wasteful. Furthermore, to ensure that different mappings
 use different shadow pages, mappings would have to be aligned to
-``KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE``.
+``KASAN_GRANULE_SIZE * PAGE_SIZE``.
 
 Instead, we share backing space across multiple mappings. We allocate
 a backing page when a mapping in vmalloc space uses a particular page

lib/test_kasan.c +1 -1

index 662f862702fc..2947274cc2d3 100644
@@ -25,7 +25,7 @@
 
 #include "../mm/kasan/kasan.h"
 
-#define OOB_TAG_OFF (IS_ENABLED(CONFIG_KASAN_GENERIC) ? 0 : KASAN_SHADOW_SCALE_SIZE)
+#define OOB_TAG_OFF (IS_ENABLED(CONFIG_KASAN_GENERIC) ? 0 : KASAN_GRANULE_SIZE)
 
 /*
  * We assign some test results to these globals to make sure the tests

lib/test_kasan_module.c +1 -1

index 2d68db6ae67b..fcb991c3aaf8 100644
@@ -15,7 +15,7 @@
 
 #include "../mm/kasan/kasan.h"
 
-#define OOB_TAG_OFF (IS_ENABLED(CONFIG_KASAN_GENERIC) ? 0 : KASAN_SHADOW_SCALE_SIZE)
+#define OOB_TAG_OFF (IS_ENABLED(CONFIG_KASAN_GENERIC) ? 0 : KASAN_GRANULE_SIZE)
 
 static noinline void __init copy_user_test(void)
 {

mm/kasan/common.c +20 -19

index a4b73fa0dd7e..f65c9f792f8f 100644
@@ -106,7 +106,7 @@ void *memcpy(void *dest, const void *src, size_t len)
 
 /*
  * Poisons the shadow memory for 'size' bytes starting from 'addr'.
- * Memory addresses should be aligned to KASAN_SHADOW_SCALE_SIZE.
+ * Memory addresses should be aligned to KASAN_GRANULE_SIZE.
  */
 void kasan_poison_memory(const void *address, size_t size, u8 value)
 {

@@ -138,13 +138,13 @@ void kasan_unpoison_memory(const void *address, size_t size)
 
        kasan_poison_memory(address, size, tag);
 
-       if (size & KASAN_SHADOW_MASK) {
+       if (size & KASAN_GRANULE_MASK) {
                u8 *shadow = (u8 *)kasan_mem_to_shadow(address + size);
 
                if (IS_ENABLED(CONFIG_KASAN_SW_TAGS))
                        *shadow = tag;
                else
-                       *shadow = size & KASAN_SHADOW_MASK;
+                       *shadow = size & KASAN_GRANULE_MASK;
        }
 }
 

@@ -296,7 +296,7 @@ void kasan_unpoison_object_data(struct kmem_cache *cache, void *object)
 void kasan_poison_object_data(struct kmem_cache *cache, void *object)
 {
        kasan_poison_memory(object,
-                       round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE),
+                       round_up(cache->object_size, KASAN_GRANULE_SIZE),
                        KASAN_KMALLOC_REDZONE);
 }
 

@@ -368,7 +368,7 @@ static inline bool shadow_invalid(u8 tag, s8 shadow_byte)
 {
        if (IS_ENABLED(CONFIG_KASAN_GENERIC))
                return shadow_byte < 0 ||
-                       shadow_byte >= KASAN_SHADOW_SCALE_SIZE;
+                       shadow_byte >= KASAN_GRANULE_SIZE;
 
        /* else CONFIG_KASAN_SW_TAGS: */
        if ((u8)shadow_byte == KASAN_TAG_INVALID)

@@ -407,7 +407,7 @@ static bool __kasan_slab_free(struct kmem_cache *cache, void *object,
                return true;
        }
 
-       rounded_up_size = round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE);
+       rounded_up_size = round_up(cache->object_size, KASAN_GRANULE_SIZE);
        kasan_poison_memory(object, rounded_up_size, KASAN_KMALLOC_FREE);
 
        if ((IS_ENABLED(CONFIG_KASAN_GENERIC) && !quarantine) ||

@@ -440,9 +440,9 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object,
                return NULL;
 
        redzone_start = round_up((unsigned long)(object + size),
-                               KASAN_SHADOW_SCALE_SIZE);
+                               KASAN_GRANULE_SIZE);
        redzone_end = round_up((unsigned long)object + cache->object_size,
-                               KASAN_SHADOW_SCALE_SIZE);
+                               KASAN_GRANULE_SIZE);
 
        if (IS_ENABLED(CONFIG_KASAN_SW_TAGS))
                tag = assign_tag(cache, object, false, keep_tag);

@@ -486,7 +486,7 @@ void * __must_check kasan_kmalloc_large(const void *ptr, size_t size,
 
        page = virt_to_page(ptr);
        redzone_start = round_up((unsigned long)(ptr + size),
-                               KASAN_SHADOW_SCALE_SIZE);
+                               KASAN_GRANULE_SIZE);
        redzone_end = (unsigned long)ptr + page_size(page);
 
        kasan_unpoison_memory(ptr, size);

@@ -584,8 +584,8 @@ static int __meminit kasan_mem_notifier(struct notifier_block *nb,
        shadow_size = nr_shadow_pages << PAGE_SHIFT;
        shadow_end = shadow_start + shadow_size;
 
-       if (WARN_ON(mem_data->nr_pages % KASAN_SHADOW_SCALE_SIZE) ||
-               WARN_ON(start_kaddr % (KASAN_SHADOW_SCALE_SIZE << PAGE_SHIFT)))
+       if (WARN_ON(mem_data->nr_pages % KASAN_GRANULE_SIZE) ||
+               WARN_ON(start_kaddr % (KASAN_GRANULE_SIZE << PAGE_SHIFT)))
                return NOTIFY_BAD;
 
        switch (action) {

@@ -743,7 +743,7 @@ void kasan_poison_vmalloc(const void *start, unsigned long size)
        if (!is_vmalloc_or_module_addr(start))
                return;
 
-       size = round_up(size, KASAN_SHADOW_SCALE_SIZE);
+       size = round_up(size, KASAN_GRANULE_SIZE);
        kasan_poison_memory(start, size, KASAN_VMALLOC_INVALID);
 }
 

@@ -856,22 +856,22 @@ void kasan_release_vmalloc(unsigned long start, unsigned long end,
        unsigned long region_start, region_end;
        unsigned long size;
 
-       region_start = ALIGN(start, PAGE_SIZE * KASAN_SHADOW_SCALE_SIZE);
-       region_end = ALIGN_DOWN(end, PAGE_SIZE * KASAN_SHADOW_SCALE_SIZE);
+       region_start = ALIGN(start, PAGE_SIZE * KASAN_GRANULE_SIZE);
+       region_end = ALIGN_DOWN(end, PAGE_SIZE * KASAN_GRANULE_SIZE);
 
        free_region_start = ALIGN(free_region_start,
-                                 PAGE_SIZE * KASAN_SHADOW_SCALE_SIZE);
+                                 PAGE_SIZE * KASAN_GRANULE_SIZE);
 
        if (start != region_start &&
            free_region_start < region_start)
-               region_start -= PAGE_SIZE * KASAN_SHADOW_SCALE_SIZE;
+               region_start -= PAGE_SIZE * KASAN_GRANULE_SIZE;
 
        free_region_end = ALIGN_DOWN(free_region_end,
-                                    PAGE_SIZE * KASAN_SHADOW_SCALE_SIZE);
+                                    PAGE_SIZE * KASAN_GRANULE_SIZE);
 
        if (end != region_end &&
            free_region_end > region_end)
-               region_end += PAGE_SIZE * KASAN_SHADOW_SCALE_SIZE;
+               region_end += PAGE_SIZE * KASAN_GRANULE_SIZE;
 
        shadow_start = kasan_mem_to_shadow((void *)region_start);
        shadow_end = kasan_mem_to_shadow((void *)region_end);

@@ -897,7 +897,8 @@ int kasan_module_alloc(void *addr, size_t size)
        unsigned long shadow_start;
 
        shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
-       scaled_size = (size + KASAN_SHADOW_MASK) >> KASAN_SHADOW_SCALE_SHIFT;
+       scaled_size = (size + KASAN_GRANULE_SIZE - 1) >>
+                               KASAN_SHADOW_SCALE_SHIFT;
        shadow_size = round_up(scaled_size, PAGE_SIZE);
 
        if (WARN_ON(!PAGE_ALIGNED(shadow_start)))

mm/kasan/generic.c +7 -7

index 7006157c674b..ec4417156943 100644
@@ -46,7 +46,7 @@ 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;
+               s8 last_accessible_byte = addr & KASAN_GRANULE_MASK;
                return unlikely(last_accessible_byte >= shadow_value);
        }
 

@@ -62,7 +62,7 @@ static __always_inline bool memory_is_poisoned_2_4_8(unsigned long 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))
+       if (unlikely(((addr + size - 1) & KASAN_GRANULE_MASK) < size - 1))
                return *shadow_addr || memory_is_poisoned_1(addr + size - 1);
 
        return memory_is_poisoned_1(addr + size - 1);

@@ -73,7 +73,7 @@ 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)))
+       if (unlikely(!IS_ALIGNED(addr, KASAN_GRANULE_SIZE)))
                return *shadow_addr || memory_is_poisoned_1(addr + 15);
 
        return *shadow_addr;

@@ -134,7 +134,7 @@ static __always_inline bool memory_is_poisoned_n(unsigned long addr,
                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)))
+                       ((long)(last_byte & KASAN_GRANULE_MASK) >= *last_shadow)))
                        return true;
        }
        return false;

@@ -200,7 +200,7 @@ void kasan_cache_shutdown(struct kmem_cache *cache)
 
 static void register_global(struct kasan_global *global)
 {
-       size_t aligned_size = round_up(global->size, KASAN_SHADOW_SCALE_SIZE);
+       size_t aligned_size = round_up(global->size, KASAN_GRANULE_SIZE);
 
        kasan_unpoison_memory(global->beg, global->size);
 

@@ -274,10 +274,10 @@ EXPORT_SYMBOL(__asan_handle_no_return);
 /* 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 rounded_up_size = round_up(size, KASAN_GRANULE_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);
+       size_t rounded_down_size = round_down(size, KASAN_GRANULE_SIZE);
 
        const void *left_redzone = (const void *)(addr -
                        KASAN_ALLOCA_REDZONE_SIZE);

mm/kasan/generic_report.c +4 -4

index 6bb3f66992df..7d5b9e5c7cfe 100644
@@ -34,7 +34,7 @@ void *find_first_bad_addr(void *addr, size_t size)
        void *p = addr;
 
        while (p < addr + size && !(*(u8 *)kasan_mem_to_shadow(p)))
-               p += KASAN_SHADOW_SCALE_SIZE;
+               p += KASAN_GRANULE_SIZE;
        return p;
 }
 

@@ -46,14 +46,14 @@ static const char *get_shadow_bug_type(struct kasan_access_info *info)
        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
+        * If shadow byte value is in [0, KASAN_GRANULE_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)
+       if (*shadow_addr > 0 && *shadow_addr <= KASAN_GRANULE_SIZE - 1)
                shadow_addr++;
 
        switch (*shadow_addr) {
-       case 0 ... KASAN_SHADOW_SCALE_SIZE - 1:
+       case 0 ... KASAN_GRANULE_SIZE - 1:
                /*
                 * In theory it's still possible to see these shadow values
                 * due to a data race in the kernel code.

mm/kasan/init.c +4 -4

index 9ce8cc5b8621..dfddd6c39fe6 100644
@@ -442,8 +442,8 @@ void kasan_remove_zero_shadow(void *start, unsigned long size)
        end = addr + (size >> KASAN_SHADOW_SCALE_SHIFT);
 
        if (WARN_ON((unsigned long)start %
-                       (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)) ||
-           WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)))
+                       (KASAN_GRANULE_SIZE * PAGE_SIZE)) ||
+           WARN_ON(size % (KASAN_GRANULE_SIZE * PAGE_SIZE)))
                return;
 
        for (; addr < end; addr = next) {

@@ -477,8 +477,8 @@ int kasan_add_zero_shadow(void *start, unsigned long size)
        shadow_end = shadow_start + (size >> KASAN_SHADOW_SCALE_SHIFT);
 
        if (WARN_ON((unsigned long)start %
-                       (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)) ||
-           WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)))
+                       (KASAN_GRANULE_SIZE * PAGE_SIZE)) ||
+           WARN_ON(size % (KASAN_GRANULE_SIZE * PAGE_SIZE)))
                return -EINVAL;
 
        ret = kasan_populate_early_shadow(shadow_start, shadow_end);

mm/kasan/kasan.h +2 -2

index 03450d3b31f7..c31e2c739301 100644
@@ -5,8 +5,8 @@
 #include <linux/kasan.h>
 #include <linux/stackdepot.h>
 
-#define KASAN_SHADOW_SCALE_SIZE (1UL << KASAN_SHADOW_SCALE_SHIFT)
-#define KASAN_SHADOW_MASK       (KASAN_SHADOW_SCALE_SIZE - 1)
+#define KASAN_GRANULE_SIZE     (1UL << KASAN_SHADOW_SCALE_SHIFT)
+#define KASAN_GRANULE_MASK     (KASAN_GRANULE_SIZE - 1)
 
 #define KASAN_TAG_KERNEL       0xFF /* native kernel pointers tag */
 #define KASAN_TAG_INVALID      0xFE /* inaccessible memory tag */

mm/kasan/report.c +5 -5

index d500923abc8b..7b8dcb799a78 100644
@@ -314,24 +314,24 @@ static bool __must_check get_address_stack_frame_info(const void *addr,
                return false;
 
        aligned_addr = round_down((unsigned long)addr, sizeof(long));
-       mem_ptr = round_down(aligned_addr, KASAN_SHADOW_SCALE_SIZE);
+       mem_ptr = round_down(aligned_addr, KASAN_GRANULE_SIZE);
        shadow_ptr = kasan_mem_to_shadow((void *)aligned_addr);
        shadow_bottom = kasan_mem_to_shadow(end_of_stack(current));
 
        while (shadow_ptr >= shadow_bottom && *shadow_ptr != KASAN_STACK_LEFT) {
                shadow_ptr--;
-               mem_ptr -= KASAN_SHADOW_SCALE_SIZE;
+               mem_ptr -= KASAN_GRANULE_SIZE;
        }
 
        while (shadow_ptr >= shadow_bottom && *shadow_ptr == KASAN_STACK_LEFT) {
                shadow_ptr--;
-               mem_ptr -= KASAN_SHADOW_SCALE_SIZE;
+               mem_ptr -= KASAN_GRANULE_SIZE;
        }
 
        if (shadow_ptr < shadow_bottom)
                return false;
 
-       frame = (const unsigned long *)(mem_ptr + KASAN_SHADOW_SCALE_SIZE);
+       frame = (const unsigned long *)(mem_ptr + KASAN_GRANULE_SIZE);
        if (frame[0] != KASAN_CURRENT_STACK_FRAME_MAGIC) {
                pr_err("KASAN internal error: frame info validation failed; invalid marker: %lu\n",
                       frame[0]);

@@ -599,6 +599,6 @@ void kasan_non_canonical_hook(unsigned long addr)
        else
                bug_type = "maybe wild-memory-access";
        pr_alert("KASAN: %s in range [0x%016lx-0x%016lx]\n", bug_type,
-                orig_addr, orig_addr + KASAN_SHADOW_MASK);
+                orig_addr, orig_addr + KASAN_GRANULE_SIZE - 1);
 }
 #endif

mm/kasan/tags_report.c +1 -2

index 5f183501b871..c87d5a343b4e 100644
@@ -76,7 +76,7 @@ void *find_first_bad_addr(void *addr, size_t size)
        void *end = p + size;
 
        while (p < end && tag == *(u8 *)kasan_mem_to_shadow(p))
-               p += KASAN_SHADOW_SCALE_SIZE;
+               p += KASAN_GRANULE_SIZE;
        return p;
 }
 
--

2.29.2.222.g5d2a92d10f8-goog

This is a preparatory commit for the upcoming addition of a new hardware tag-based (MTE-based) KASAN mode.

The new mode won't be using shadow memory, so only build init.c that contains shadow initialization code for software modes.

No functional changes for software modes.

Signed-off-by Andrey Konovalov <[email protected]>

Signed-off-by Vincenzo Frascino <[email protected]>

Reviewed-by Marco Elver <[email protected]>

---
Change-Id: I8d68c47345afc1dbedadde738f34a874dcae5080

---
 mm/kasan/Makefile | 6 +++---
 mm/kasan/init.c   | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

mm/kasan/Makefile +3 -3

index 370d970e5ab5..7cf685bb51bd 100644
@@ -29,6 +29,6 @@ CFLAGS_report.o := $(CC_FLAGS_KASAN_RUNTIME)
 CFLAGS_tags.o := $(CC_FLAGS_KASAN_RUNTIME)
 CFLAGS_tags_report.o := $(CC_FLAGS_KASAN_RUNTIME)
 
-obj-$(CONFIG_KASAN) := common.o init.o report.o
-obj-$(CONFIG_KASAN_GENERIC) += generic.o generic_report.o quarantine.o
-obj-$(CONFIG_KASAN_SW_TAGS) += tags.o tags_report.o
+obj-$(CONFIG_KASAN) := common.o report.o
+obj-$(CONFIG_KASAN_GENERIC) += init.o generic.o generic_report.o quarantine.o
+obj-$(CONFIG_KASAN_SW_TAGS) += init.o tags.o tags_report.o

mm/kasan/init.c +1 -2

index dfddd6c39fe6..1a71eaa8c5f9 100644
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * This file contains some kasan initialization code.
+ * This file contains KASAN shadow initialization code.
  *
  * Copyright (c) 2015 Samsung Electronics Co., Ltd.
  * Author: Andrey Ryabinin <[email protected]>
--

2.29.2.222.g5d2a92d10f8-goog

This is a preparatory commit for the upcoming addition of a new hardware tag-based (MTE-based) KASAN mode.

The new mode won't be using shadow memory. Move all shadow-related code to shadow.c, which is only enabled for software KASAN modes that use shadow memory.

No functional changes for software modes.

Signed-off-by Andrey Konovalov <[email protected]>

Signed-off-by Vincenzo Frascino <[email protected]>

Reviewed-by Marco Elver <[email protected]>

---
Change-Id: Ic1c32ce72d4649848e9e6a1f2c8dd269c77673f2

---
 mm/kasan/Makefile |   6 +-
 mm/kasan/common.c | 486 +-------------------------------------------
 mm/kasan/shadow.c | 505 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 510 insertions(+), 487 deletions(-)
 create mode 100644 mm/kasan/shadow.c

mm/kasan/Makefile +4 -2

index 7cf685bb51bd..7cc1031e1ef8 100644
@@ -10,6 +10,7 @@ CFLAGS_REMOVE_generic_report.o = $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_init.o = $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_quarantine.o = $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_report.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_shadow.o = $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_tags.o = $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_tags_report.o = $(CC_FLAGS_FTRACE)
 

@@ -26,9 +27,10 @@ CFLAGS_generic_report.o := $(CC_FLAGS_KASAN_RUNTIME)
 CFLAGS_init.o := $(CC_FLAGS_KASAN_RUNTIME)
 CFLAGS_quarantine.o := $(CC_FLAGS_KASAN_RUNTIME)
 CFLAGS_report.o := $(CC_FLAGS_KASAN_RUNTIME)
+CFLAGS_shadow.o := $(CC_FLAGS_KASAN_RUNTIME)
 CFLAGS_tags.o := $(CC_FLAGS_KASAN_RUNTIME)
 CFLAGS_tags_report.o := $(CC_FLAGS_KASAN_RUNTIME)
 
 obj-$(CONFIG_KASAN) := common.o report.o
-obj-$(CONFIG_KASAN_GENERIC) += init.o generic.o generic_report.o quarantine.o
-obj-$(CONFIG_KASAN_SW_TAGS) += init.o tags.o tags_report.o
+obj-$(CONFIG_KASAN_GENERIC) += init.o generic.o generic_report.o shadow.o quarantine.o
+obj-$(CONFIG_KASAN_SW_TAGS) += init.o shadow.o tags.o tags_report.o

mm/kasan/common.c +1 -485

index f65c9f792f8f..123abfb760d4 100644
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * This file contains common generic and tag-based KASAN code.
+ * This file contains common KASAN code.
  *
  * Copyright (c) 2014 Samsung Electronics Co., Ltd.
  * Author: Andrey Ryabinin <[email protected]>

@@ -13,7 +13,6 @@
 #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>

@@ -26,12 +25,8 @@
 #include <linux/stacktrace.h>
 #include <linux/string.h>
 #include <linux/types.h>
-#include <linux/vmalloc.h>
 #include <linux/bug.h>
 
-#include <asm/cacheflush.h>
-#include <asm/tlbflush.h>
-
 #include "kasan.h"
 #include "../slab.h"
 

@@ -61,93 +56,6 @@ void kasan_disable_current(void)
        current->kasan_depth--;
 }
 
-bool __kasan_check_read(const volatile void *p, unsigned int size)
-{
-       return check_memory_region((unsigned long)p, size, false, _RET_IP_);
-}
-EXPORT_SYMBOL(__kasan_check_read);
-
-bool __kasan_check_write(const volatile void *p, unsigned int size)
-{
-       return check_memory_region((unsigned long)p, size, true, _RET_IP_);
-}
-EXPORT_SYMBOL(__kasan_check_write);
-
-#undef memset
-void *memset(void *addr, int c, size_t len)
-{
-       if (!check_memory_region((unsigned long)addr, len, true, _RET_IP_))
-               return NULL;
-
-       return __memset(addr, c, len);
-}
-
-#ifdef __HAVE_ARCH_MEMMOVE
-#undef memmove
-void *memmove(void *dest, const void *src, size_t len)
-{
-       if (!check_memory_region((unsigned long)src, len, false, _RET_IP_) ||
-           !check_memory_region((unsigned long)dest, len, true, _RET_IP_))
-               return NULL;
-
-       return __memmove(dest, src, len);
-}
-#endif
-
-#undef memcpy
-void *memcpy(void *dest, const void *src, size_t len)
-{
-       if (!check_memory_region((unsigned long)src, len, false, _RET_IP_) ||
-           !check_memory_region((unsigned long)dest, len, true, _RET_IP_))
-               return NULL;
-
-       return __memcpy(dest, src, len);
-}
-
-/*
- * Poisons the shadow memory for 'size' bytes starting from 'addr'.
- * Memory addresses should be aligned to KASAN_GRANULE_SIZE.
- */
-void kasan_poison_memory(const void *address, size_t size, u8 value)
-{
-       void *shadow_start, *shadow_end;
-
-       /*
-        * Perform shadow offset calculation based on untagged address, as
-        * some of the callers (e.g. kasan_poison_object_data) pass tagged
-        * addresses to this function.
-        */
-       address = reset_tag(address);
-
-       shadow_start = kasan_mem_to_shadow(address);
-       shadow_end = kasan_mem_to_shadow(address + size);
-
-       __memset(shadow_start, value, shadow_end - shadow_start);
-}
-
-void kasan_unpoison_memory(const void *address, size_t size)
-{
-       u8 tag = get_tag(address);
-
-       /*
-        * Perform shadow offset calculation based on untagged address, as
-        * some of the callers (e.g. kasan_unpoison_object_data) pass tagged
-        * addresses to this function.
-        */
-       address = reset_tag(address);
-
-       kasan_poison_memory(address, size, tag);
-
-       if (size & KASAN_GRANULE_MASK) {
-               u8 *shadow = (u8 *)kasan_mem_to_shadow(address + size);
-
-               if (IS_ENABLED(CONFIG_KASAN_SW_TAGS))
-                       *shadow = tag;
-               else
-                       *shadow = size & KASAN_GRANULE_MASK;
-       }
-}
-
 static void __kasan_unpoison_stack(struct task_struct *task, const void *sp)
 {
        void *base = task_stack_page(task);

@@ -535,395 +443,3 @@ void kasan_kfree_large(void *ptr, unsigned long ip)
                kasan_report_invalid_free(ptr, ip);
        /* The object will be poisoned by page_alloc. */
 }
-
-#ifdef CONFIG_MEMORY_HOTPLUG
-static bool shadow_mapped(unsigned long addr)
-{
-       pgd_t *pgd = pgd_offset_k(addr);
-       p4d_t *p4d;
-       pud_t *pud;
-       pmd_t *pmd;
-       pte_t *pte;
-
-       if (pgd_none(*pgd))
-               return false;
-       p4d = p4d_offset(pgd, addr);
-       if (p4d_none(*p4d))
-               return false;
-       pud = pud_offset(p4d, addr);
-       if (pud_none(*pud))
-               return false;
-
-       /*
-        * We can't use pud_large() or pud_huge(), the first one is
-        * arch-specific, the last one depends on HUGETLB_PAGE.  So let's abuse
-        * pud_bad(), if pud is bad then it's bad because it's huge.
-        */
-       if (pud_bad(*pud))
-               return true;
-       pmd = pmd_offset(pud, addr);
-       if (pmd_none(*pmd))
-               return false;
-
-       if (pmd_bad(*pmd))
-               return true;
-       pte = pte_offset_kernel(pmd, addr);
-       return !pte_none(*pte);
-}
-
-static int __meminit kasan_mem_notifier(struct notifier_block *nb,
-                       unsigned long action, void *data)
-{
-       struct memory_notify *mem_data = data;
-       unsigned long nr_shadow_pages, start_kaddr, shadow_start;
-       unsigned long shadow_end, shadow_size;
-
-       nr_shadow_pages = mem_data->nr_pages >> KASAN_SHADOW_SCALE_SHIFT;
-       start_kaddr = (unsigned long)pfn_to_kaddr(mem_data->start_pfn);
-       shadow_start = (unsigned long)kasan_mem_to_shadow((void *)start_kaddr);
-       shadow_size = nr_shadow_pages << PAGE_SHIFT;
-       shadow_end = shadow_start + shadow_size;
-
-       if (WARN_ON(mem_data->nr_pages % KASAN_GRANULE_SIZE) ||
-               WARN_ON(start_kaddr % (KASAN_GRANULE_SIZE << PAGE_SHIFT)))
-               return NOTIFY_BAD;
-
-       switch (action) {
-       case MEM_GOING_ONLINE: {
-               void *ret;
-
-               /*
-                * If shadow is mapped already than it must have been mapped
-                * during the boot. This could happen if we onlining previously
-                * offlined memory.
-                */
-               if (shadow_mapped(shadow_start))
-                       return NOTIFY_OK;
-
-               ret = __vmalloc_node_range(shadow_size, PAGE_SIZE, shadow_start,
-                                       shadow_end, GFP_KERNEL,
-                                       PAGE_KERNEL, VM_NO_GUARD,
-                                       pfn_to_nid(mem_data->start_pfn),
-                                       __builtin_return_address(0));
-               if (!ret)
-                       return NOTIFY_BAD;
-
-               kmemleak_ignore(ret);
-               return NOTIFY_OK;
-       }
-       case MEM_CANCEL_ONLINE:
-       case MEM_OFFLINE: {
-               struct vm_struct *vm;
-
-               /*
-                * shadow_start was either mapped during boot by kasan_init()
-                * or during memory online by __vmalloc_node_range().
-                * In the latter case we can use vfree() to free shadow.
-                * Non-NULL result of the find_vm_area() will tell us if
-                * that was the second case.
-                *
-                * Currently it's not possible to free shadow mapped
-                * during boot by kasan_init(). It's because the code
-                * to do that hasn't been written yet. So we'll just
-                * leak the memory.
-                */
-               vm = find_vm_area((void *)shadow_start);
-               if (vm)
-                       vfree((void *)shadow_start);
-       }
-       }
-
-       return NOTIFY_OK;
-}
-
-static int __init kasan_memhotplug_init(void)
-{
-       hotplug_memory_notifier(kasan_mem_notifier, 0);
-
-       return 0;
-}
-
-core_initcall(kasan_memhotplug_init);
-#endif
-
-#ifdef CONFIG_KASAN_VMALLOC
-
-static int kasan_populate_vmalloc_pte(pte_t *ptep, unsigned long addr,
-                                     void *unused)
-{
-       unsigned long page;
-       pte_t pte;
-
-       if (likely(!pte_none(*ptep)))
-               return 0;
-
-       page = __get_free_page(GFP_KERNEL);
-       if (!page)
-               return -ENOMEM;
-
-       memset((void *)page, KASAN_VMALLOC_INVALID, PAGE_SIZE);
-       pte = pfn_pte(PFN_DOWN(__pa(page)), PAGE_KERNEL);
-
-       spin_lock(&init_mm.page_table_lock);
-       if (likely(pte_none(*ptep))) {
-               set_pte_at(&init_mm, addr, ptep, pte);
-               page = 0;
-       }
-       spin_unlock(&init_mm.page_table_lock);
-       if (page)
-               free_page(page);
-       return 0;
-}
-
-int kasan_populate_vmalloc(unsigned long addr, unsigned long size)
-{
-       unsigned long shadow_start, shadow_end;
-       int ret;
-
-       if (!is_vmalloc_or_module_addr((void *)addr))
-               return 0;
-
-       shadow_start = (unsigned long)kasan_mem_to_shadow((void *)addr);
-       shadow_start = ALIGN_DOWN(shadow_start, PAGE_SIZE);
-       shadow_end = (unsigned long)kasan_mem_to_shadow((void *)addr + size);
-       shadow_end = ALIGN(shadow_end, PAGE_SIZE);
-
-       ret = apply_to_page_range(&init_mm, shadow_start,
-                                 shadow_end - shadow_start,
-                                 kasan_populate_vmalloc_pte, NULL);
-       if (ret)
-               return ret;
-
-       flush_cache_vmap(shadow_start, shadow_end);
-
-       /*
-        * We need to be careful about inter-cpu effects here. Consider:
-        *
-        *   CPU#0                                CPU#1
-        * WRITE_ONCE(p, vmalloc(100));         while (x = READ_ONCE(p)) ;
-        *                                      p[99] = 1;
-        *
-        * With compiler instrumentation, that ends up looking like this:
-        *
-        *   CPU#0                                CPU#1
-        * // vmalloc() allocates memory
-        * // let a = area->addr
-        * // we reach kasan_populate_vmalloc
-        * // and call kasan_unpoison_memory:
-        * STORE shadow(a), unpoison_val
-        * ...
-        * STORE shadow(a+99), unpoison_val     x = LOAD p
-        * // rest of vmalloc process           <data dependency>
-        * STORE p, a                           LOAD shadow(x+99)
-        *
-        * If there is no barrier between the end of unpoisioning the shadow
-        * and the store of the result to p, the stores could be committed
-        * in a different order by CPU#0, and CPU#1 could erroneously observe
-        * poison in the shadow.
-        *
-        * We need some sort of barrier between the stores.
-        *
-        * In the vmalloc() case, this is provided by a smp_wmb() in
-        * clear_vm_uninitialized_flag(). In the per-cpu allocator and in
-        * get_vm_area() and friends, the caller gets shadow allocated but
-        * doesn't have any pages mapped into the virtual address space that
-        * has been reserved. Mapping those pages in will involve taking and
-        * releasing a page-table lock, which will provide the barrier.
-        */
-
-       return 0;
-}
-
-/*
- * Poison the shadow for a vmalloc region. Called as part of the
- * freeing process at the time the region is freed.
- */
-void kasan_poison_vmalloc(const void *start, unsigned long size)
-{
-       if (!is_vmalloc_or_module_addr(start))
-               return;
-
-       size = round_up(size, KASAN_GRANULE_SIZE);
-       kasan_poison_memory(start, size, KASAN_VMALLOC_INVALID);
-}
-
-void kasan_unpoison_vmalloc(const void *start, unsigned long size)
-{
-       if (!is_vmalloc_or_module_addr(start))
-               return;
-
-       kasan_unpoison_memory(start, size);
-}
-
-static int kasan_depopulate_vmalloc_pte(pte_t *ptep, unsigned long addr,
-                                       void *unused)
-{
-       unsigned long page;
-
-       page = (unsigned long)__va(pte_pfn(*ptep) << PAGE_SHIFT);
-
-       spin_lock(&init_mm.page_table_lock);
-
-       if (likely(!pte_none(*ptep))) {
-               pte_clear(&init_mm, addr, ptep);
-               free_page(page);
-       }
-       spin_unlock(&init_mm.page_table_lock);
-
-       return 0;
-}
-
-/*
- * Release the backing for the vmalloc region [start, end), which
- * lies within the free region [free_region_start, free_region_end).
- *
- * This can be run lazily, long after the region was freed. It runs
- * under vmap_area_lock, so it's not safe to interact with the vmalloc/vmap
- * infrastructure.
- *
- * How does this work?
- * -------------------
- *
- * We have a region that is page aligned, labelled as A.
- * That might not map onto the shadow in a way that is page-aligned:
- *
- *                    start                     end
- *                    v                         v
- * |????????|????????|AAAAAAAA|AA....AA|AAAAAAAA|????????| < vmalloc
- *  -------- -------- --------          -------- --------
- *      |        |       |                 |        |
- *      |        |       |         /-------/        |
- *      \-------\|/------/         |/---------------/
- *              |||                ||
- *             |??AAAAAA|AAAAAAAA|AA??????|                < shadow
- *                 (1)      (2)      (3)
- *
- * First we align the start upwards and the end downwards, so that the
- * shadow of the region aligns with shadow page boundaries. In the
- * example, this gives us the shadow page (2). This is the shadow entirely
- * covered by this allocation.
- *
- * Then we have the tricky bits. We want to know if we can free the
- * partially covered shadow pages - (1) and (3) in the example. For this,
- * we are given the start and end of the free region that contains this
- * allocation. Extending our previous example, we could have:
- *
- *  free_region_start                                    free_region_end
- *  |                 start                     end      |
- *  v                 v                         v        v
- * |FFFFFFFF|FFFFFFFF|AAAAAAAA|AA....AA|AAAAAAAA|FFFFFFFF| < vmalloc
- *  -------- -------- --------          -------- --------
- *      |        |       |                 |        |
- *      |        |       |         /-------/        |
- *      \-------\|/------/         |/---------------/
- *              |||                ||
- *             |FFAAAAAA|AAAAAAAA|AAF?????|                < shadow
- *                 (1)      (2)      (3)
- *
- * Once again, we align the start of the free region up, and the end of
- * the free region down so that the shadow is page aligned. So we can free
- * page (1) - we know no allocation currently uses anything in that page,
- * because all of it is in the vmalloc free region. But we cannot free
- * page (3), because we can't be sure that the rest of it is unused.
- *
- * We only consider pages that contain part of the original region for
- * freeing: we don't try to free other pages from the free region or we'd
- * end up trying to free huge chunks of virtual address space.
- *
- * Concurrency
- * -----------
- *
- * How do we know that we're not freeing a page that is simultaneously
- * being used for a fresh allocation in kasan_populate_vmalloc(_pte)?
- *
- * We _can_ have kasan_release_vmalloc and kasan_populate_vmalloc running
- * at the same time. While we run under free_vmap_area_lock, the population
- * code does not.
- *
- * free_vmap_area_lock instead operates to ensure that the larger range
- * [free_region_start, free_region_end) is safe: because __alloc_vmap_area and
- * the per-cpu region-finding algorithm both run under free_vmap_area_lock,
- * no space identified as free will become used while we are running. This
- * means that so long as we are careful with alignment and only free shadow
- * pages entirely covered by the free region, we will not run in to any
- * trouble - any simultaneous allocations will be for disjoint regions.
- */
-void kasan_release_vmalloc(unsigned long start, unsigned long end,
-                          unsigned long free_region_start,
-                          unsigned long free_region_end)
-{
-       void *shadow_start, *shadow_end;
-       unsigned long region_start, region_end;
-       unsigned long size;
-
-       region_start = ALIGN(start, PAGE_SIZE * KASAN_GRANULE_SIZE);
-       region_end = ALIGN_DOWN(end, PAGE_SIZE * KASAN_GRANULE_SIZE);
-
-       free_region_start = ALIGN(free_region_start,
-                                 PAGE_SIZE * KASAN_GRANULE_SIZE);
-
-       if (start != region_start &&
-           free_region_start < region_start)
-               region_start -= PAGE_SIZE * KASAN_GRANULE_SIZE;
-
-       free_region_end = ALIGN_DOWN(free_region_end,
-                                    PAGE_SIZE * KASAN_GRANULE_SIZE);
-
-       if (end != region_end &&
-           free_region_end > region_end)
-               region_end += PAGE_SIZE * KASAN_GRANULE_SIZE;
-
-       shadow_start = kasan_mem_to_shadow((void *)region_start);
-       shadow_end = kasan_mem_to_shadow((void *)region_end);
-
-       if (shadow_end > shadow_start) {
-               size = shadow_end - shadow_start;
-               apply_to_existing_page_range(&init_mm,
-                                            (unsigned long)shadow_start,
-                                            size, kasan_depopulate_vmalloc_pte,
-                                            NULL);
-               flush_tlb_kernel_range((unsigned long)shadow_start,
-                                      (unsigned long)shadow_end);
-       }
-}
-
-#else /* CONFIG_KASAN_VMALLOC */
-
-int kasan_module_alloc(void *addr, size_t size)
-{
-       void *ret;
-       size_t scaled_size;
-       size_t shadow_size;
-       unsigned long shadow_start;
-
-       shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
-       scaled_size = (size + KASAN_GRANULE_SIZE - 1) >>
-                               KASAN_SHADOW_SCALE_SHIFT;
-       shadow_size = round_up(scaled_size, PAGE_SIZE);
-
-       if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
-               return -EINVAL;
-
-       ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
-                       shadow_start + shadow_size,
-                       GFP_KERNEL,
-                       PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
-                       __builtin_return_address(0));
-
-       if (ret) {
-               __memset(ret, KASAN_SHADOW_INIT, shadow_size);
-               find_vm_area(addr)->flags |= VM_KASAN;
-               kmemleak_ignore(ret);
-               return 0;
-       }
-
-       return -ENOMEM;
-}
-
-void kasan_free_shadow(const struct vm_struct *vm)
-{
-       if (vm->flags & VM_KASAN)
-               vfree(kasan_mem_to_shadow(vm->addr));
-}
-
-#endif

mm/kasan/shadow.c new file +505 -1

new file mode 100644
index 000000000000..ca0cc4c31454
@@ -0,0 +1,505 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file contains KASAN runtime code that manages shadow memory for
+ * generic and software tag-based KASAN modes.
+ *
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd.
+ * Author: Andrey Ryabinin <[email protected]>
+ *
+ * Some code borrowed from https://github.com/xairy/kasan-prototype by
+ *        Andrey Konovalov <[email protected]>
+ */
+
+#include <linux/init.h>
+#include <linux/kasan.h>
+#include <linux/kernel.h>
+#include <linux/kmemleak.h>
+#include <linux/memory.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/vmalloc.h>
+
+#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
+
+#include "kasan.h"
+
+bool __kasan_check_read(const volatile void *p, unsigned int size)
+{
+       return check_memory_region((unsigned long)p, size, false, _RET_IP_);
+}
+EXPORT_SYMBOL(__kasan_check_read);
+
+bool __kasan_check_write(const volatile void *p, unsigned int size)
+{
+       return check_memory_region((unsigned long)p, size, true, _RET_IP_);
+}
+EXPORT_SYMBOL(__kasan_check_write);
+
+#undef memset
+void *memset(void *addr, int c, size_t len)
+{
+       if (!check_memory_region((unsigned long)addr, len, true, _RET_IP_))
+               return NULL;
+
+       return __memset(addr, c, len);
+}
+
+#ifdef __HAVE_ARCH_MEMMOVE
+#undef memmove
+void *memmove(void *dest, const void *src, size_t len)
+{
+       if (!check_memory_region((unsigned long)src, len, false, _RET_IP_) ||
+           !check_memory_region((unsigned long)dest, len, true, _RET_IP_))
+               return NULL;
+
+       return __memmove(dest, src, len);
+}
+#endif
+
+#undef memcpy
+void *memcpy(void *dest, const void *src, size_t len)
+{
+       if (!check_memory_region((unsigned long)src, len, false, _RET_IP_) ||
+           !check_memory_region((unsigned long)dest, len, true, _RET_IP_))
+               return NULL;
+
+       return __memcpy(dest, src, len);
+}
+
+/*
+ * Poisons the shadow memory for 'size' bytes starting from 'addr'.
+ * Memory addresses should be aligned to KASAN_GRANULE_SIZE.
+ */
+void kasan_poison_memory(const void *address, size_t size, u8 value)
+{
+       void *shadow_start, *shadow_end;
+
+       /*
+        * Perform shadow offset calculation based on untagged address, as
+        * some of the callers (e.g. kasan_poison_object_data) pass tagged
+        * addresses to this function.
+        */
+       address = reset_tag(address);
+
+       shadow_start = kasan_mem_to_shadow(address);
+       shadow_end = kasan_mem_to_shadow(address + size);
+
+       __memset(shadow_start, value, shadow_end - shadow_start);
+}
+
+void kasan_unpoison_memory(const void *address, size_t size)
+{
+       u8 tag = get_tag(address);
+
+       /*
+        * Perform shadow offset calculation based on untagged address, as
+        * some of the callers (e.g. kasan_unpoison_object_data) pass tagged
+        * addresses to this function.
+        */
+       address = reset_tag(address);
+
+       kasan_poison_memory(address, size, tag);
+
+       if (size & KASAN_GRANULE_MASK) {
+               u8 *shadow = (u8 *)kasan_mem_to_shadow(address + size);
+
+               if (IS_ENABLED(CONFIG_KASAN_SW_TAGS))
+                       *shadow = tag;
+               else
+                       *shadow = size & KASAN_GRANULE_MASK;
+       }
+}
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+static bool shadow_mapped(unsigned long addr)
+{
+       pgd_t *pgd = pgd_offset_k(addr);
+       p4d_t *p4d;
+       pud_t *pud;
+       pmd_t *pmd;
+       pte_t *pte;
+
+       if (pgd_none(*pgd))
+               return false;
+       p4d = p4d_offset(pgd, addr);
+       if (p4d_none(*p4d))
+               return false;
+       pud = pud_offset(p4d, addr);
+       if (pud_none(*pud))
+               return false;
+
+       /*
+        * We can't use pud_large() or pud_huge(), the first one is
+        * arch-specific, the last one depends on HUGETLB_PAGE.  So let's abuse
+        * pud_bad(), if pud is bad then it's bad because it's huge.
+        */
+       if (pud_bad(*pud))
+               return true;
+       pmd = pmd_offset(pud, addr);
+       if (pmd_none(*pmd))
+               return false;
+
+       if (pmd_bad(*pmd))
+               return true;
+       pte = pte_offset_kernel(pmd, addr);
+       return !pte_none(*pte);
+}
+
+static int __meminit kasan_mem_notifier(struct notifier_block *nb,
+                       unsigned long action, void *data)
+{
+       struct memory_notify *mem_data = data;
+       unsigned long nr_shadow_pages, start_kaddr, shadow_start;
+       unsigned long shadow_end, shadow_size;
+
+       nr_shadow_pages = mem_data->nr_pages >> KASAN_SHADOW_SCALE_SHIFT;
+       start_kaddr = (unsigned long)pfn_to_kaddr(mem_data->start_pfn);
+       shadow_start = (unsigned long)kasan_mem_to_shadow((void *)start_kaddr);
+       shadow_size = nr_shadow_pages << PAGE_SHIFT;
+       shadow_end = shadow_start + shadow_size;
+
+       if (WARN_ON(mem_data->nr_pages % KASAN_GRANULE_SIZE) ||
+               WARN_ON(start_kaddr % (KASAN_GRANULE_SIZE << PAGE_SHIFT)))
+               return NOTIFY_BAD;
+
+       switch (action) {
+       case MEM_GOING_ONLINE: {
+               void *ret;
+
+               /*
+                * If shadow is mapped already than it must have been mapped
+                * during the boot. This could happen if we onlining previously
+                * offlined memory.
+                */
+               if (shadow_mapped(shadow_start))
+                       return NOTIFY_OK;
+
+               ret = __vmalloc_node_range(shadow_size, PAGE_SIZE, shadow_start,
+                                       shadow_end, GFP_KERNEL,
+                                       PAGE_KERNEL, VM_NO_GUARD,
+                                       pfn_to_nid(mem_data->start_pfn),
+                                       __builtin_return_address(0));
+               if (!ret)
+                       return NOTIFY_BAD;
+
+               kmemleak_ignore(ret);
+               return NOTIFY_OK;
+       }
+       case MEM_CANCEL_ONLINE:
+       case MEM_OFFLINE: {
+               struct vm_struct *vm;
+
+               /*
+                * shadow_start was either mapped during boot by kasan_init()
+                * or during memory online by __vmalloc_node_range().
+                * In the latter case we can use vfree() to free shadow.
+                * Non-NULL result of the find_vm_area() will tell us if
+                * that was the second case.
+                *
+                * Currently it's not possible to free shadow mapped
+                * during boot by kasan_init(). It's because the code
+                * to do that hasn't been written yet. So we'll just
+                * leak the memory.
+                */
+               vm = find_vm_area((void *)shadow_start);
+               if (vm)
+                       vfree((void *)shadow_start);
+       }
+       }
+
+       return NOTIFY_OK;
+}
+
+static int __init kasan_memhotplug_init(void)
+{
+       hotplug_memory_notifier(kasan_mem_notifier, 0);
+
+       return 0;
+}
+
+core_initcall(kasan_memhotplug_init);
+#endif
+
+#ifdef CONFIG_KASAN_VMALLOC
+
+static int kasan_populate_vmalloc_pte(pte_t *ptep, unsigned long addr,
+                                     void *unused)
+{
+       unsigned long page;
+       pte_t pte;
+
+       if (likely(!pte_none(*ptep)))
+               return 0;
+
+       page = __get_free_page(GFP_KERNEL);
+       if (!page)
+               return -ENOMEM;
+
+       memset((void *)page, KASAN_VMALLOC_INVALID, PAGE_SIZE);
+       pte = pfn_pte(PFN_DOWN(__pa(page)), PAGE_KERNEL);
+
+       spin_lock(&init_mm.page_table_lock);
+       if (likely(pte_none(*ptep))) {
+               set_pte_at(&init_mm, addr, ptep, pte);
+               page = 0;
+       }
+       spin_unlock(&init_mm.page_table_lock);
+       if (page)
+               free_page(page);
+       return 0;
+}
+
+int kasan_populate_vmalloc(unsigned long addr, unsigned long size)
+{
+       unsigned long shadow_start, shadow_end;
+       int ret;
+
+       if (!is_vmalloc_or_module_addr((void *)addr))
+               return 0;
+
+       shadow_start = (unsigned long)kasan_mem_to_shadow((void *)addr);
+       shadow_start = ALIGN_DOWN(shadow_start, PAGE_SIZE);
+       shadow_end = (unsigned long)kasan_mem_to_shadow((void *)addr + size);
+       shadow_end = ALIGN(shadow_end, PAGE_SIZE);
+
+       ret = apply_to_page_range(&init_mm, shadow_start,
+                                 shadow_end - shadow_start,
+                                 kasan_populate_vmalloc_pte, NULL);
+       if (ret)
+               return ret;
+
+       flush_cache_vmap(shadow_start, shadow_end);
+
+       /*
+        * We need to be careful about inter-cpu effects here. Consider:
+        *
+        *   CPU#0                                CPU#1
+        * WRITE_ONCE(p, vmalloc(100));         while (x = READ_ONCE(p)) ;
+        *                                      p[99] = 1;
+        *
+        * With compiler instrumentation, that ends up looking like this:
+        *
+        *   CPU#0                                CPU#1
+        * // vmalloc() allocates memory
+        * // let a = area->addr
+        * // we reach kasan_populate_vmalloc
+        * // and call kasan_unpoison_memory:
+        * STORE shadow(a), unpoison_val
+        * ...
+        * STORE shadow(a+99), unpoison_val     x = LOAD p
+        * // rest of vmalloc process           <data dependency>
+        * STORE p, a                           LOAD shadow(x+99)
+        *
+        * If there is no barrier between the end of unpoisioning the shadow
+        * and the store of the result to p, the stores could be committed
+        * in a different order by CPU#0, and CPU#1 could erroneously observe
+        * poison in the shadow.
+        *
+        * We need some sort of barrier between the stores.
+        *
+        * In the vmalloc() case, this is provided by a smp_wmb() in
+        * clear_vm_uninitialized_flag(). In the per-cpu allocator and in
+        * get_vm_area() and friends, the caller gets shadow allocated but
+        * doesn't have any pages mapped into the virtual address space that
+        * has been reserved. Mapping those pages in will involve taking and
+        * releasing a page-table lock, which will provide the barrier.
+        */
+
+       return 0;
+}
+
+/*
+ * Poison the shadow for a vmalloc region. Called as part of the
+ * freeing process at the time the region is freed.
+ */
+void kasan_poison_vmalloc(const void *start, unsigned long size)
+{
+       if (!is_vmalloc_or_module_addr(start))
+               return;
+
+       size = round_up(size, KASAN_GRANULE_SIZE);
+       kasan_poison_memory(start, size, KASAN_VMALLOC_INVALID);
+}
+
+void kasan_unpoison_vmalloc(const void *start, unsigned long size)
+{
+       if (!is_vmalloc_or_module_addr(start))
+               return;
+
+       kasan_unpoison_memory(start, size);
+}
+
+static int kasan_depopulate_vmalloc_pte(pte_t *ptep, unsigned long addr,
+                                       void *unused)
+{
+       unsigned long page;
+
+       page = (unsigned long)__va(pte_pfn(*ptep) << PAGE_SHIFT);
+
+       spin_lock(&init_mm.page_table_lock);
+
+       if (likely(!pte_none(*ptep))) {
+               pte_clear(&init_mm, addr, ptep);
+               free_page(page);
+       }
+       spin_unlock(&init_mm.page_table_lock);
+
+       return 0;
+}
+
+/*
+ * Release the backing for the vmalloc region [start, end), which
+ * lies within the free region [free_region_start, free_region_end).
+ *
+ * This can be run lazily, long after the region was freed. It runs
+ * under vmap_area_lock, so it's not safe to interact with the vmalloc/vmap
+ * infrastructure.
+ *
+ * How does this work?
+ * -------------------
+ *
+ * We have a region that is page aligned, labelled as A.
+ * That might not map onto the shadow in a way that is page-aligned:
+ *
+ *                    start                     end
+ *                    v                         v
+ * |????????|????????|AAAAAAAA|AA....AA|AAAAAAAA|????????| < vmalloc
+ *  -------- -------- --------          -------- --------
+ *      |        |       |                 |        |
+ *      |        |       |         /-------/        |
+ *      \-------\|/------/         |/---------------/
+ *              |||                ||
+ *             |??AAAAAA|AAAAAAAA|AA??????|                < shadow
+ *                 (1)      (2)      (3)
+ *
+ * First we align the start upwards and the end downwards, so that the
+ * shadow of the region aligns with shadow page boundaries. In the
+ * example, this gives us the shadow page (2). This is the shadow entirely
+ * covered by this allocation.
+ *
+ * Then we have the tricky bits. We want to know if we can free the
+ * partially covered shadow pages - (1) and (3) in the example. For this,
+ * we are given the start and end of the free region that contains this
+ * allocation. Extending our previous example, we could have:
+ *
+ *  free_region_start                                    free_region_end
+ *  |                 start                     end      |
+ *  v                 v                         v        v
+ * |FFFFFFFF|FFFFFFFF|AAAAAAAA|AA....AA|AAAAAAAA|FFFFFFFF| < vmalloc
+ *  -------- -------- --------          -------- --------
+ *      |        |       |                 |        |
+ *      |        |       |         /-------/        |
+ *      \-------\|/------/         |/---------------/
+ *              |||                ||
+ *             |FFAAAAAA|AAAAAAAA|AAF?????|                < shadow
+ *                 (1)      (2)      (3)
+ *
+ * Once again, we align the start of the free region up, and the end of
+ * the free region down so that the shadow is page aligned. So we can free
+ * page (1) - we know no allocation currently uses anything in that page,
+ * because all of it is in the vmalloc free region. But we cannot free
+ * page (3), because we can't be sure that the rest of it is unused.
+ *
+ * We only consider pages that contain part of the original region for
+ * freeing: we don't try to free other pages from the free region or we'd
+ * end up trying to free huge chunks of virtual address space.
+ *
+ * Concurrency
+ * -----------
+ *
+ * How do we know that we're not freeing a page that is simultaneously
+ * being used for a fresh allocation in kasan_populate_vmalloc(_pte)?
+ *
+ * We _can_ have kasan_release_vmalloc and kasan_populate_vmalloc running
+ * at the same time. While we run under free_vmap_area_lock, the population
+ * code does not.
+ *
+ * free_vmap_area_lock instead operates to ensure that the larger range
+ * [free_region_start, free_region_end) is safe: because __alloc_vmap_area and
+ * the per-cpu region-finding algorithm both run under free_vmap_area_lock,
+ * no space identified as free will become used while we are running. This
+ * means that so long as we are careful with alignment and only free shadow
+ * pages entirely covered by the free region, we will not run in to any
+ * trouble - any simultaneous allocations will be for disjoint regions.
+ */
+void kasan_release_vmalloc(unsigned long start, unsigned long end,
+                          unsigned long free_region_start,
+                          unsigned long free_region_end)
+{
+       void *shadow_start, *shadow_end;
+       unsigned long region_start, region_end;
+       unsigned long size;
+
+       region_start = ALIGN(start, PAGE_SIZE * KASAN_GRANULE_SIZE);
+       region_end = ALIGN_DOWN(end, PAGE_SIZE * KASAN_GRANULE_SIZE);
+
+       free_region_start = ALIGN(free_region_start,
+                                 PAGE_SIZE * KASAN_GRANULE_SIZE);
+
+       if (start != region_start &&
+           free_region_start < region_start)
+               region_start -= PAGE_SIZE * KASAN_GRANULE_SIZE;
+
+       free_region_end = ALIGN_DOWN(free_region_end,
+                                    PAGE_SIZE * KASAN_GRANULE_SIZE);
+
+       if (end != region_end &&
+           free_region_end > region_end)
+               region_end += PAGE_SIZE * KASAN_GRANULE_SIZE;
+
+       shadow_start = kasan_mem_to_shadow((void *)region_start);
+       shadow_end = kasan_mem_to_shadow((void *)region_end);
+
+       if (shadow_end > shadow_start) {
+               size = shadow_end - shadow_start;
+               apply_to_existing_page_range(&init_mm,
+                                            (unsigned long)shadow_start,
+                                            size, kasan_depopulate_vmalloc_pte,
+                                            NULL);
+               flush_tlb_kernel_range((unsigned long)shadow_start,
+                                      (unsigned long)shadow_end);
+       }
+}
+
+#else /* CONFIG_KASAN_VMALLOC */
+
+int kasan_module_alloc(void *addr, size_t size)
+{
+       void *ret;
+       size_t scaled_size;
+       size_t shadow_size;
+       unsigned long shadow_start;
+
+       shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
+       scaled_size = (size + KASAN_GRANULE_SIZE - 1) >>
+                               KASAN_SHADOW_SCALE_SHIFT;
+       shadow_size = round_up(scaled_size, PAGE_SIZE);
+
+       if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
+               return -EINVAL;
+
+       ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
+                       shadow_start + shadow_size,
+                       GFP_KERNEL,
+                       PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
+                       __builtin_return_address(0));
+
+       if (ret) {
+               __memset(ret, KASAN_SHADOW_INIT, shadow_size);
+               find_vm_area(addr)->flags |= VM_KASAN;
+               kmemleak_ignore(ret);
+               return 0;
+       }
+
+       return -ENOMEM;
+}
+
+void kasan_free_shadow(const struct vm_struct *vm)
+{
+       if (vm->flags & VM_KASAN)
+               vfree(kasan_mem_to_shadow(vm->addr));
+}
+
+#endif
--

2.29.2.222.g5d2a92d10f8-goog