Thread (8 messages) 8 messages, 3 authors, 2021-06-28

Re: [PATCH v4 2/3] kasan: integrate the common part of two KASAN tag-based modes

From: Marco Elver <elver@google.com>
Date: 2021-06-28 06:00:27
Also in: linux-mediatek, linux-mm, lkml

On Sat, 26 Jun 2021 at 12:09, Kuan-Ying Lee [off-list ref] wrote:
1. Move kasan_get_free_track() and kasan_set_free_info()
   into tags.c and combine these two functions for
   SW_TAGS and HW_TAGS kasan mode.
2. Move kasan_get_bug_type() to report_tags.c and
   make this function compatible for SW_TAGS and
   HW_TAGS kasan mode.

Signed-off-by: Kuan-Ying Lee <redacted>
Suggested-by: Marco Elver <elver@google.com>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Marco Elver <elver@google.com>

quoted hunk ↗ jump to hunk
---
 mm/kasan/Makefile         |  4 +--
 mm/kasan/hw_tags.c        | 22 ---------------
 mm/kasan/report_hw_tags.c |  5 ----
 mm/kasan/report_sw_tags.c | 43 ----------------------------
 mm/kasan/report_tags.c    | 51 +++++++++++++++++++++++++++++++++
 mm/kasan/sw_tags.c        | 41 ---------------------------
 mm/kasan/tags.c           | 59 +++++++++++++++++++++++++++++++++++++++
 7 files changed, 112 insertions(+), 113 deletions(-)
 create mode 100644 mm/kasan/report_tags.c
 create mode 100644 mm/kasan/tags.c
diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile
index 9fe39a66388a..adcd9acaef61 100644
--- a/mm/kasan/Makefile
+++ b/mm/kasan/Makefile
@@ -37,5 +37,5 @@ CFLAGS_sw_tags.o := $(CC_FLAGS_KASAN_RUNTIME)

 obj-$(CONFIG_KASAN) := common.o report.o
 obj-$(CONFIG_KASAN_GENERIC) += init.o generic.o report_generic.o shadow.o quarantine.o
-obj-$(CONFIG_KASAN_HW_TAGS) += hw_tags.o report_hw_tags.o
-obj-$(CONFIG_KASAN_SW_TAGS) += init.o report_sw_tags.o shadow.o sw_tags.o
+obj-$(CONFIG_KASAN_HW_TAGS) += hw_tags.o report_hw_tags.o tags.o report_tags.o
+obj-$(CONFIG_KASAN_SW_TAGS) += init.o report_sw_tags.o shadow.o sw_tags.o tags.o report_tags.o
diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c
index ed5e5b833d61..4ea8c368b5b8 100644
--- a/mm/kasan/hw_tags.c
+++ b/mm/kasan/hw_tags.c
@@ -216,28 +216,6 @@ void __init kasan_init_hw_tags(void)
        pr_info("KernelAddressSanitizer initialized\n");
 }

-void kasan_set_free_info(struct kmem_cache *cache,
-                               void *object, u8 tag)
-{
-       struct kasan_alloc_meta *alloc_meta;
-
-       alloc_meta = kasan_get_alloc_meta(cache, object);
-       if (alloc_meta)
-               kasan_set_track(&alloc_meta->free_track[0], GFP_NOWAIT);
-}
-
-struct kasan_track *kasan_get_free_track(struct kmem_cache *cache,
-                               void *object, u8 tag)
-{
-       struct kasan_alloc_meta *alloc_meta;
-
-       alloc_meta = kasan_get_alloc_meta(cache, object);
-       if (!alloc_meta)
-               return NULL;
-
-       return &alloc_meta->free_track[0];
-}
-
 void kasan_alloc_pages(struct page *page, unsigned int order, gfp_t flags)
 {
        /*
diff --git a/mm/kasan/report_hw_tags.c b/mm/kasan/report_hw_tags.c
index 42b2168755d6..5dbbbb930e7a 100644
--- a/mm/kasan/report_hw_tags.c
+++ b/mm/kasan/report_hw_tags.c
@@ -15,11 +15,6 @@

 #include "kasan.h"

-const char *kasan_get_bug_type(struct kasan_access_info *info)
-{
-       return "invalid-access";
-}
-
 void *kasan_find_first_bad_addr(void *addr, size_t size)
 {
        return kasan_reset_tag(addr);
diff --git a/mm/kasan/report_sw_tags.c b/mm/kasan/report_sw_tags.c
index 821a14a19a92..d2298c357834 100644
--- a/mm/kasan/report_sw_tags.c
+++ b/mm/kasan/report_sw_tags.c
@@ -29,49 +29,6 @@
 #include "kasan.h"
 #include "../slab.h"

-const char *kasan_get_bug_type(struct kasan_access_info *info)
-{
-#ifdef CONFIG_KASAN_TAGS_IDENTIFY
-       struct kasan_alloc_meta *alloc_meta;
-       struct kmem_cache *cache;
-       struct page *page;
-       const void *addr;
-       void *object;
-       u8 tag;
-       int i;
-
-       tag = get_tag(info->access_addr);
-       addr = kasan_reset_tag(info->access_addr);
-       page = kasan_addr_to_page(addr);
-       if (page && PageSlab(page)) {
-               cache = page->slab_cache;
-               object = nearest_obj(cache, page, (void *)addr);
-               alloc_meta = kasan_get_alloc_meta(cache, object);
-
-               if (alloc_meta) {
-                       for (i = 0; i < KASAN_NR_FREE_STACKS; i++) {
-                               if (alloc_meta->free_pointer_tag[i] == tag)
-                                       return "use-after-free";
-                       }
-               }
-               return "out-of-bounds";
-       }
-
-#endif
-       /*
-        * If access_size is a negative number, then it has reason to be
-        * defined as out-of-bounds bug type.
-        *
-        * Casting negative numbers to size_t would indeed turn up as
-        * a large size_t and its value will be larger than ULONG_MAX/2,
-        * so that this can qualify as out-of-bounds.
-        */
-       if (info->access_addr + info->access_size < info->access_addr)
-               return "out-of-bounds";
-
-       return "invalid-access";
-}
-
 void *kasan_find_first_bad_addr(void *addr, size_t size)
 {
        u8 tag = get_tag(addr);
diff --git a/mm/kasan/report_tags.c b/mm/kasan/report_tags.c
new file mode 100644
index 000000000000..8a319fc16dab
--- /dev/null
+++ b/mm/kasan/report_tags.c
@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd.
+ * Copyright (c) 2020 Google, Inc.
+ */
+
+#include "kasan.h"
+#include "../slab.h"
+
+const char *kasan_get_bug_type(struct kasan_access_info *info)
+{
+#ifdef CONFIG_KASAN_TAGS_IDENTIFY
+       struct kasan_alloc_meta *alloc_meta;
+       struct kmem_cache *cache;
+       struct page *page;
+       const void *addr;
+       void *object;
+       u8 tag;
+       int i;
+
+       tag = get_tag(info->access_addr);
+       addr = kasan_reset_tag(info->access_addr);
+       page = kasan_addr_to_page(addr);
+       if (page && PageSlab(page)) {
+               cache = page->slab_cache;
+               object = nearest_obj(cache, page, (void *)addr);
+               alloc_meta = kasan_get_alloc_meta(cache, object);
+
+               if (alloc_meta) {
+                       for (i = 0; i < KASAN_NR_FREE_STACKS; i++) {
+                               if (alloc_meta->free_pointer_tag[i] == tag)
+                                       return "use-after-free";
+                       }
+               }
+               return "out-of-bounds";
+       }
+#endif
+
+       /*
+        * If access_size is a negative number, then it has reason to be
+        * defined as out-of-bounds bug type.
+        *
+        * Casting negative numbers to size_t would indeed turn up as
+        * a large size_t and its value will be larger than ULONG_MAX/2,
+        * so that this can qualify as out-of-bounds.
+        */
+       if (info->access_addr + info->access_size < info->access_addr)
+               return "out-of-bounds";
+
+       return "invalid-access";
+}
diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c
index dd05e6c801fa..bd3f540feb47 100644
--- a/mm/kasan/sw_tags.c
+++ b/mm/kasan/sw_tags.c
@@ -167,47 +167,6 @@ void __hwasan_tag_memory(unsigned long addr, u8 tag, unsigned long size)
 }
 EXPORT_SYMBOL(__hwasan_tag_memory);

-void kasan_set_free_info(struct kmem_cache *cache,
-                               void *object, u8 tag)
-{
-       struct kasan_alloc_meta *alloc_meta;
-       u8 idx = 0;
-
-       alloc_meta = kasan_get_alloc_meta(cache, object);
-       if (!alloc_meta)
-               return;
-
-#ifdef CONFIG_KASAN_TAGS_IDENTIFY
-       idx = alloc_meta->free_track_idx;
-       alloc_meta->free_pointer_tag[idx] = tag;
-       alloc_meta->free_track_idx = (idx + 1) % KASAN_NR_FREE_STACKS;
-#endif
-
-       kasan_set_track(&alloc_meta->free_track[idx], GFP_NOWAIT);
-}
-
-struct kasan_track *kasan_get_free_track(struct kmem_cache *cache,
-                               void *object, u8 tag)
-{
-       struct kasan_alloc_meta *alloc_meta;
-       int i = 0;
-
-       alloc_meta = kasan_get_alloc_meta(cache, object);
-       if (!alloc_meta)
-               return NULL;
-
-#ifdef CONFIG_KASAN_TAGS_IDENTIFY
-       for (i = 0; i < KASAN_NR_FREE_STACKS; i++) {
-               if (alloc_meta->free_pointer_tag[i] == tag)
-                       break;
-       }
-       if (i == KASAN_NR_FREE_STACKS)
-               i = alloc_meta->free_track_idx;
-#endif
-
-       return &alloc_meta->free_track[i];
-}
-
 void kasan_tag_mismatch(unsigned long addr, unsigned long access_info,
                        unsigned long ret_ip)
 {
diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c
new file mode 100644
index 000000000000..8f48b9502a17
--- /dev/null
+++ b/mm/kasan/tags.c
@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file contains common tag-based KASAN code.
+ *
+ * Copyright (c) 2018 Google, Inc.
+ * Copyright (c) 2020 Google, Inc.
+ */
+
+#include <linux/init.h>
+#include <linux/kasan.h>
+#include <linux/kernel.h>
+#include <linux/memory.h>
+#include <linux/mm.h>
+#include <linux/static_key.h>
+#include <linux/string.h>
+#include <linux/types.h>
+
+#include "kasan.h"
+
+void kasan_set_free_info(struct kmem_cache *cache,
+                               void *object, u8 tag)
+{
+       struct kasan_alloc_meta *alloc_meta;
+       u8 idx = 0;
+
+       alloc_meta = kasan_get_alloc_meta(cache, object);
+       if (!alloc_meta)
+               return;
+
+#ifdef CONFIG_KASAN_TAGS_IDENTIFY
+       idx = alloc_meta->free_track_idx;
+       alloc_meta->free_pointer_tag[idx] = tag;
+       alloc_meta->free_track_idx = (idx + 1) % KASAN_NR_FREE_STACKS;
+#endif
+
+       kasan_set_track(&alloc_meta->free_track[idx], GFP_NOWAIT);
+}
+
+struct kasan_track *kasan_get_free_track(struct kmem_cache *cache,
+                               void *object, u8 tag)
+{
+       struct kasan_alloc_meta *alloc_meta;
+       int i = 0;
+
+       alloc_meta = kasan_get_alloc_meta(cache, object);
+       if (!alloc_meta)
+               return NULL;
+
+#ifdef CONFIG_KASAN_TAGS_IDENTIFY
+       for (i = 0; i < KASAN_NR_FREE_STACKS; i++) {
+               if (alloc_meta->free_pointer_tag[i] == tag)
+                       break;
+       }
+       if (i == KASAN_NR_FREE_STACKS)
+               i = alloc_meta->free_track_idx;
+#endif
+
+       return &alloc_meta->free_track[i];
+}
--
2.18.0

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