diff mbox series

[v3,2/3] kasan: integrate the common part of two KASAN tag-based modes

Message ID 20210620114756.31304-3-Kuan-Ying.Lee@mediatek.com (mailing list archive)
State New, archived
Headers show
Series kasan: add memory corruption identification support for hw tag-based kasan | expand

Commit Message

Kuan-Ying Lee (李冠穎) June 20, 2021, 11:47 a.m. UTC 
1. Move kasan_get_free_track() and kasan_set_free_info()
   into tags.c
2. Move kasan_get_bug_type() to header file

Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
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>
---
 mm/kasan/Makefile         |  4 +--
 mm/kasan/hw_tags.c        | 22 ---------------
 mm/kasan/report_hw_tags.c |  6 +---
 mm/kasan/report_sw_tags.c | 46 +-----------------------------
 mm/kasan/report_tags.h    | 55 ++++++++++++++++++++++++++++++++++++
 mm/kasan/sw_tags.c        | 41 ---------------------------
 mm/kasan/tags.c           | 59 +++++++++++++++++++++++++++++++++++++++
 7 files changed, 118 insertions(+), 115 deletions(-)
 create mode 100644 mm/kasan/report_tags.h
 create mode 100644 mm/kasan/tags.c

Comments

Alexander Potapenko June 22, 2021, 9:27 a.m. UTC | #1 
> diff --git a/mm/kasan/report_tags.h b/mm/kasan/report_tags.h
> new file mode 100644
> index 000000000000..1cb872177904
> --- /dev/null
> +++ b/mm/kasan/report_tags.h
Why don't you make it a C file instead?

> +const char *kasan_get_bug_type(struct kasan_access_info *info)
If this function has to be in the header, it should be declared as
static inline.
But I don't think it has to be there in the first place.
Marco Elver June 22, 2021, 9:48 a.m. UTC | #2 
On Tue, 22 Jun 2021 at 11:28, Alexander Potapenko <glider@google.com> wrote:
>
> > diff --git a/mm/kasan/report_tags.h b/mm/kasan/report_tags.h
> > new file mode 100644
> > index 000000000000..1cb872177904
> > --- /dev/null
> > +++ b/mm/kasan/report_tags.h
> Why don't you make it a C file instead?

Yes, good point. report_{hw,sw}_tags.c essentially define it, but it's
called by report.c code.

I think I suggested to make it a header first because there were still
parts that were report_{hw,sw}_tags.c specific, and the helper
function would be used by those 2 to build their version of
kasan_get_bug_type(), but that doesn't seem to be the case anymore.

> > +const char *kasan_get_bug_type(struct kasan_access_info *info)
> If this function has to be in the header, it should be declared as
> static inline.
> But I don't think it has to be there in the first place.
Andrey Konovalov June 22, 2021, 1:54 p.m. UTC | #3 
On Sun, Jun 20, 2021 at 2:48 PM Kuan-Ying Lee
<Kuan-Ying.Lee@mediatek.com> wrote:
>
> 1. Move kasan_get_free_track() and kasan_set_free_info()
>    into tags.c

Please mention that the patch doesn't only move but also combines
these functions for SW_TAGS and HW_TAGS modes.

> --- /dev/null
> +++ b/mm/kasan/report_tags.h
> @@ -0,0 +1,55 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (c) 2014 Samsung Electronics Co., Ltd.
> + * Copyright (c) 2020 Google, Inc.
> + */
> +#ifndef __MM_KASAN_REPORT_TAGS_H
> +#define __MM_KASAN_REPORT_TAGS_H
> +
> +#include "kasan.h"
> +#include "../slab.h"
> +
> +const char *kasan_get_bug_type(struct kasan_access_info *info)

As mentioned by Alex, don't put this implementation into a header. Put
it into report_tags.c. The declaration is already in kasan.h.


> +{
> +#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";
> +}
Kuan-Ying Lee (李冠穎) June 23, 2021, 3:17 a.m. UTC | #4 
On Tue, 2021-06-22 at 16:54 +0300, Andrey Konovalov wrote:
> On Sun, Jun 20, 2021 at 2:48 PM Kuan-Ying Lee
> <Kuan-Ying.Lee@mediatek.com> wrote:
> > 
> > 1. Move kasan_get_free_track() and kasan_set_free_info()
> >    into tags.c
> 
> Please mention that the patch doesn't only move but also combines
> these functions for SW_TAGS and HW_TAGS modes.
> 

Got it.

> > --- /dev/null
> > +++ b/mm/kasan/report_tags.h
> > @@ -0,0 +1,55 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Copyright (c) 2014 Samsung Electronics Co., Ltd.
> > + * Copyright (c) 2020 Google, Inc.
> > + */
> > +#ifndef __MM_KASAN_REPORT_TAGS_H
> > +#define __MM_KASAN_REPORT_TAGS_H
> > +
> > +#include "kasan.h"
> > +#include "../slab.h"
> > +
> > +const char *kasan_get_bug_type(struct kasan_access_info *info)
> 
> As mentioned by Alex, don't put this implementation into a header.
> Put
> it into report_tags.c. The declaration is already in kasan.h.
> 

Ok. I will refactor in v4.
Thanks for suggestions.

> > +{
> > +#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 mbox series

Patch

diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile
index 9fe39a66388a..634de6c1da9b 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-$(CONFIG_KASAN_HW_TAGS) += hw_tags.o report_hw_tags.o tags.o
+obj-$(CONFIG_KASAN_SW_TAGS) += init.o report_sw_tags.o shadow.o sw_tags.o 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..ef5e7378f3aa 100644
--- a/mm/kasan/report_hw_tags.c
+++ b/mm/kasan/report_hw_tags.c
@@ -14,11 +14,7 @@ 
 #include <linux/types.h>
 
 #include "kasan.h"
-
-const char *kasan_get_bug_type(struct kasan_access_info *info)
-{
-	return "invalid-access";
-}
+#include "report_tags.h"
 
 void *kasan_find_first_bad_addr(void *addr, size_t size)
 {
diff --git a/mm/kasan/report_sw_tags.c b/mm/kasan/report_sw_tags.c
index 821a14a19a92..d965a170083e 100644
--- a/mm/kasan/report_sw_tags.c
+++ b/mm/kasan/report_sw_tags.c
@@ -26,51 +26,7 @@ 
 
 #include <asm/sections.h>
 
-#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";
-}
+#include "report_tags.h"
 
 void *kasan_find_first_bad_addr(void *addr, size_t size)
 {
diff --git a/mm/kasan/report_tags.h b/mm/kasan/report_tags.h
new file mode 100644
index 000000000000..1cb872177904
--- /dev/null
+++ b/mm/kasan/report_tags.h
@@ -0,0 +1,55 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd.
+ * Copyright (c) 2020 Google, Inc.
+ */
+#ifndef __MM_KASAN_REPORT_TAGS_H
+#define __MM_KASAN_REPORT_TAGS_H
+
+#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";
+}
+
+#endif
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];
+}