linux-kernel - [PATCH v2 2/2] mm, kasan: add a ksize() test

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Date:	Wed, 13 Apr 2016 13:20:10 +0200
From:	Alexander Potapenko <glider@...gle.com>
To:	adech.fo@...il.com, dvyukov@...gle.com, cl@...ux.com,
	akpm@...ux-foundation.org, ryabinin.a.a@...il.com, kcc@...gle.com
Cc:	kasan-dev@...glegroups.com, linux-kernel@...r.kernel.org,
	linux-mm@...ck.org
Subject: [PATCH v2 2/2] mm, kasan: add a ksize() test

Add a test that makes sure ksize() unpoisons the whole chunk.

Signed-off-by: Alexander Potapenko <glider@...gle.com>
---
v2: - splitted v1 into two patches
---
 lib/test_kasan.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 82169fb..48e5a0b 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -344,6 +344,25 @@ static noinline void __init kasan_stack_oob(void)
 	*(volatile char *)p;
 }
 
+static noinline void __init ksize_unpoisons_memory(void)
+{
+	char *ptr;
+	size_t size = 123, real_size = size;
+
+	pr_info("ksize() unpoisons the whole allocated chunk\n");
+	ptr = kmalloc(size, GFP_KERNEL);
+	if (!ptr) {
+		pr_err("Allocation failed\n");
+		return;
+	}
+	real_size = ksize(ptr);
+	/* This access doesn't trigger an error. */
+	ptr[size] = 'x';
+	/* This one does. */
+	ptr[real_size] = 'y';
+	kfree(ptr);
+}
+
 static int __init kmalloc_tests_init(void)
 {
 	kmalloc_oob_right();
@@ -367,6 +386,7 @@ static int __init kmalloc_tests_init(void)
 	kmem_cache_oob();
 	kasan_stack_oob();
 	kasan_global_oob();
+	ksize_unpoisons_memory();
 	return -EAGAIN;
 }
 
-- 
2.8.0.rc3.226.g39d4020