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From: Andrey Konovalov <andreyknvl@google.com>
To: "Andrey Ryabinin" <aryabinin@virtuozzo.com>,
	"Alexander Potapenko" <glider@google.com>,
	"Dmitry Vyukov" <dvyukov@google.com>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"Catalin Marinas" <catalin.marinas@arm.com>,
	"Will Deacon" <will.deacon@arm.com>,
	"Christopher Li" <sparse@chrisli.org>,
	"Christoph Lameter" <cl@linux.com>,
	"Pekka Enberg" <penberg@kernel.org>,
	"David Rientjes" <rientjes@google.com>,
	"Joonsoo Kim" <iamjoonsoo.kim@lge.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Masahiro Yamada" <yamada.masahiro@socionext.com>,
	"Michal Marek" <michal.lkml@markovi.net>,
	"Andrey Konovalov" <andreyknvl@google.com>,
	"Mark Rutland" <mark.rutland@arm.com>,
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	"Yury Norov" <ynorov@caviumnetworks.com>,
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	kasan-dev@googlegroups.com, linux-doc@vger.kernel.org,
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Cc: Kostya Serebryany <kcc@google.com>,
	Evgeniy Stepanov <eugenis@google.com>,
	Lee Smith <Lee.Smith@arm.com>,
	Ramana Radhakrishnan <Ramana.Radhakrishnan@arm.com>,
	Jacob Bramley <Jacob.Bramley@arm.com>,
	Ruben Ayrapetyan <Ruben.Ayrapetyan@arm.com>,
	Kees Cook <keescook@google.com>, Jann Horn <jannh@google.com>,
	Mark Brand <markbrand@google.com>,
	Chintan Pandya <cpandya@codeaurora.org>
Subject: [PATCH v1 12/16] khwasan: add bug reporting routines
Date: Tue,  8 May 2018 19:20:58 +0200	[thread overview]
Message-ID: <0474f59eee0b14a7e72264efa2fcff276f03839f.1525798754.git.andreyknvl@google.com> (raw)
In-Reply-To: <cover.1525798753.git.andreyknvl@google.com>
In-Reply-To: <cover.1525798753.git.andreyknvl@google.com>

This commit adds rountines, that print KHWASAN error reports. Those are
quite similar to KASAN, the difference is:

1. The way KHWASAN finds the first bad shadow cell (with a mismatching
   tag). KHWASAN compares memory tags from the shadow memory to the pointer
   tag.

2. KHWASAN reports all bugs with the "KASAN: invalid-access" header. This
   is done, so various external tools that already parse the kernel logs
   looking for KASAN reports wouldn't need to be changed.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 include/linux/kasan.h     |  3 +++
 mm/kasan/kasan.h          |  7 +++++
 mm/kasan/kasan_report.c   |  7 ++---
 mm/kasan/khwasan_report.c | 21 +++++++++++++++
 mm/kasan/report.c         | 57 +++++++++++++++++++++------------------
 5 files changed, 64 insertions(+), 31 deletions(-)

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index d7624b879d86..e209027f3b52 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -161,6 +161,9 @@ void *khwasan_set_tag(const void *addr, u8 tag);
 u8 khwasan_get_tag(const void *addr);
 void *khwasan_reset_tag(const void *ptr);
 
+void kasan_report(unsigned long addr, size_t size,
+			bool write, unsigned long ip);
+
 #else /* CONFIG_KASAN_HW */
 
 static inline void khwasan_init(void) { }
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index a76aee9e095f..620941d1e84f 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -128,8 +128,15 @@ void kasan_poison_shadow(const void *address, size_t size, u8 value);
 void check_memory_region(unsigned long addr, size_t size, bool write,
 				unsigned long ret_ip);
 
+void *find_first_bad_addr(void *addr, size_t size);
 const char *get_bug_type(struct kasan_access_info *info);
 
+#ifdef CONFIG_KASAN_HW
+void print_tags(u8 addr_tag, const void *addr);
+#else
+static inline void print_tags(u8 addr_tag, const void *addr) { }
+#endif
+
 void kasan_report(unsigned long addr, size_t size,
 		bool is_write, unsigned long ip);
 void kasan_report_invalid_free(void *object, unsigned long ip);
diff --git a/mm/kasan/kasan_report.c b/mm/kasan/kasan_report.c
index 2d8decbecbd5..fdf2d77e3125 100644
--- a/mm/kasan/kasan_report.c
+++ b/mm/kasan/kasan_report.c
@@ -33,10 +33,10 @@
 #include "kasan.h"
 #include "../slab.h"
 
-static const void *find_first_bad_addr(const void *addr, size_t size)
+void *find_first_bad_addr(void *addr, size_t size)
 {
 	u8 shadow_val = *(u8 *)kasan_mem_to_shadow(addr);
-	const void *first_bad_addr = addr;
+	void *first_bad_addr = addr;
 
 	while (!shadow_val && first_bad_addr < addr + size) {
 		first_bad_addr += KASAN_SHADOW_SCALE_SIZE;
@@ -50,9 +50,6 @@ static const char *get_shadow_bug_type(struct kasan_access_info *info)
 	const char *bug_type = "unknown-crash";
 	u8 *shadow_addr;
 
-	info->first_bad_addr = find_first_bad_addr(info->access_addr,
-						info->access_size);
-
 	shadow_addr = (u8 *)kasan_mem_to_shadow(info->first_bad_addr);
 
 	/*
diff --git a/mm/kasan/khwasan_report.c b/mm/kasan/khwasan_report.c
index 2edbc3c76be5..51238b404b08 100644
--- a/mm/kasan/khwasan_report.c
+++ b/mm/kasan/khwasan_report.c
@@ -37,3 +37,24 @@ const char *get_bug_type(struct kasan_access_info *info)
 {
 	return "invalid-access";
 }
+
+void *find_first_bad_addr(void *addr, size_t size)
+{
+	u8 tag = get_tag(addr);
+	void *untagged_addr = reset_tag(addr);
+	u8 *shadow = (u8 *)kasan_mem_to_shadow(untagged_addr);
+	void *first_bad_addr = untagged_addr;
+
+	while (*shadow == tag && first_bad_addr < untagged_addr + size) {
+		first_bad_addr += KASAN_SHADOW_SCALE_SIZE;
+		shadow = (u8 *)kasan_mem_to_shadow(first_bad_addr);
+	}
+	return first_bad_addr;
+}
+
+void print_tags(u8 addr_tag, const void *addr)
+{
+	u8 *shadow = (u8 *)kasan_mem_to_shadow(addr);
+
+	pr_err("Pointer tag: [%02x], memory tag: [%02x]\n", addr_tag, *shadow);
+}
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 155247a6f8a8..e031c78f2e52 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -64,11 +64,10 @@ static int __init kasan_set_multi_shot(char *str)
 }
 __setup("kasan_multi_shot", kasan_set_multi_shot);
 
-static void print_error_description(struct kasan_access_info *info,
-					const char *bug_type)
+static void print_error_description(struct kasan_access_info *info)
 {
 	pr_err("BUG: KASAN: %s in %pS\n",
-		bug_type, (void *)info->ip);
+		get_bug_type(info), (void *)info->ip);
 	pr_err("%s of size %zu at addr %px by task %s/%d\n",
 		info->is_write ? "Write" : "Read", info->access_size,
 		info->access_addr, current->comm, task_pid_nr(current));
@@ -272,6 +271,8 @@ void kasan_report_invalid_free(void *object, unsigned long ip)
 
 	start_report(&flags);
 	pr_err("BUG: KASAN: double-free or invalid-free in %pS\n", (void *)ip);
+	print_tags(get_tag(object), reset_tag(object));
+	object = reset_tag(object);
 	pr_err("\n");
 	print_address_description(object);
 	pr_err("\n");
@@ -279,41 +280,45 @@ void kasan_report_invalid_free(void *object, unsigned long ip)
 	end_report(&flags);
 }
 
-static void kasan_report_error(struct kasan_access_info *info)
-{
-	unsigned long flags;
-
-	start_report(&flags);
-
-	print_error_description(info, get_bug_type(info));
-	pr_err("\n");
-
-	if (!addr_has_shadow(info->access_addr)) {
-		dump_stack();
-	} else {
-		print_address_description((void *)info->access_addr);
-		pr_err("\n");
-		print_shadow_for_address(info->first_bad_addr);
-	}
-
-	end_report(&flags);
-}
-
 void kasan_report(unsigned long addr, size_t size,
 		bool is_write, unsigned long ip)
 {
 	struct kasan_access_info info;
+	void *tagged_addr;
+	void *untagged_addr;
+	unsigned long flags;
 
 	if (likely(!report_enabled()))
 		return;
 
 	disable_trace_on_warning();
 
-	info.access_addr = (void *)addr;
-	info.first_bad_addr = (void *)addr;
+	tagged_addr = (void *)addr;
+	untagged_addr = reset_tag(tagged_addr);
+
+	info.access_addr = tagged_addr;
+	if (addr_has_shadow(untagged_addr))
+		info.first_bad_addr = find_first_bad_addr(tagged_addr, size);
+	else
+		info.first_bad_addr = untagged_addr;
 	info.access_size = size;
 	info.is_write = is_write;
 	info.ip = ip;
 
-	kasan_report_error(&info);
+	start_report(&flags);
+
+	print_error_description(&info);
+	if (addr_has_shadow(untagged_addr))
+		print_tags(get_tag(tagged_addr), info.first_bad_addr);
+	pr_err("\n");
+
+	if (addr_has_shadow(untagged_addr)) {
+		print_address_description(untagged_addr);
+		pr_err("\n");
+		print_shadow_for_address(info.first_bad_addr);
+	} else {
+		dump_stack();
+	}
+
+	end_report(&flags);
 }
-- 
2.17.0.441.gb46fe60e1d-goog

  parent reply	other threads:[~2018-05-08 17:20 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-08 17:20 [PATCH v1 00/16] khwasan: kernel hardware assisted address sanitizer Andrey Konovalov
2018-05-08 17:20 ` [PATCH v1 01/16] khwasan, mm: change kasan hooks signatures Andrey Konovalov
2018-05-14 16:56   ` Andrey Ryabinin
2018-05-08 17:20 ` [PATCH v1 02/16] khwasan: move common kasan and khwasan code to common.c Andrey Konovalov
2018-05-15 13:28   ` Andrey Ryabinin
2018-05-08 17:20 ` [PATCH v1 03/16] khwasan: add CONFIG_KASAN_GENERIC and CONFIG_KASAN_HW Andrey Konovalov
2018-05-14 16:57   ` Andrey Ryabinin
2018-05-08 17:20 ` [PATCH v1 04/16] khwasan, arm64: adjust shadow size for CONFIG_KASAN_HW Andrey Konovalov
2018-05-08 17:20 ` [PATCH v1 05/16] khwasan: initialize shadow to 0xff Andrey Konovalov
2018-05-08 17:20 ` [PATCH v1 06/16] khwasan, arm64: untag virt address in __kimg_to_phys Andrey Konovalov
2018-05-08 17:20 ` [PATCH v1 07/16] khwasan, arm64: fix up fault handling logic Andrey Konovalov
2018-05-08 17:20 ` [PATCH v1 08/16] khwasan: add tag related helper functions Andrey Konovalov
2018-05-14 16:58   ` Andrey Ryabinin
2018-05-08 17:20 ` [PATCH v1 09/16] khwasan, arm64: enable top byte ignore for the kernel Andrey Konovalov
2018-05-08 17:20 ` [PATCH v1 10/16] khwasan, mm: perform untagged pointers comparison in krealloc Andrey Konovalov
2018-05-08 17:20 ` [PATCH v1 11/16] khwasan: split out kasan_report.c from report.c Andrey Konovalov
2018-05-08 17:20 ` Andrey Konovalov [this message]
2018-05-08 17:20 ` [PATCH v1 13/16] khwasan: add hooks implementation Andrey Konovalov
2018-05-15 13:13   ` Andrey Ryabinin
2018-05-08 17:21 ` [PATCH v1 14/16] khwasan, arm64: add brk handler for inline instrumentation Andrey Konovalov
2018-05-08 17:21 ` [PATCH v1 15/16] khwasan, mm, arm64: tag non slab memory allocated via pagealloc Andrey Konovalov
2018-05-15 14:06   ` Andrey Ryabinin
2018-05-08 17:21 ` [PATCH v1 16/16] khwasan: update kasan documentation Andrey Konovalov
2018-05-09  5:26   ` Mike Rapoport
2018-05-09 12:13     ` Andrey Konovalov

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